From 6961c9a4c2fe8612db222bfd1693e38f7a43a2cd Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 29 Nov 2022 16:07:17 -0500
Subject: expr: Remove the synthetic flag

Only diagnostics cares about this, and we can just check if the pointers
are equal.
---
 src/opt.c | 5 -----
 1 file changed, 5 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index fa2e66c..f7f80d7 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -366,10 +366,6 @@ static struct bfs_expr *negate_expr(struct bfs_expr *rhs, char **argv) {
 		return NULL;
 	}
 
-	if (argv == &fake_not_arg) {
-		expr->synthetic = true;
-	}
-
 	expr->lhs = NULL;
 	expr->rhs = rhs;
 	return expr;
@@ -404,7 +400,6 @@ static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr
 		expr->eval_fn = eval_and;
 		expr->argv = &fake_and_arg;
 	}
-	expr->synthetic = true;
 
 	expr->lhs = negate_expr(expr->lhs, argv);
 	expr->rhs = negate_expr(expr->rhs, argv);
-- 
cgit v1.2.3


From 1d68b43f1554ee82b3ac5772534a5ecbd57855a7 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 30 Nov 2022 10:51:45 -0500
Subject: expr: Remove the singleton bfs_{true,false} expressions

---
 src/color.c |   4 +
 src/expr.h  |   5 -
 src/opt.c   |  68 ++++++++------
 src/parse.c | 306 +++++++++++++++++++++++++++++++++---------------------------
 4 files changed, 209 insertions(+), 174 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/color.c b/src/color.c
index 98fe9f2..94fcac8 100644
--- a/src/color.c
+++ b/src/color.c
@@ -877,6 +877,10 @@ static int cbuff(CFILE *cfile, const char *format, ...);
 
 /** Dump a parsed expression tree, for debugging. */
 static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
+	if (!expr) {
+		return dstrcat(&cfile->buffer, "(null)");
+	}
+
 	if (dstrcat(&cfile->buffer, "(") != 0) {
 		return -1;
 	}
diff --git a/src/expr.h b/src/expr.h
index 2de8958..e541d8e 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -202,11 +202,6 @@ struct bfs_expr {
 	};
 };
 
-/** Singleton true expression instance. */
-extern struct bfs_expr bfs_true;
-/** Singleton false expression instance. */
-extern struct bfs_expr bfs_false;
-
 /**
  * Create a new expression.
  */
diff --git a/src/opt.c b/src/opt.c
index f7f80d7..441c611 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -344,6 +344,13 @@ static void opt_warning(const struct opt_state *state, const struct bfs_expr *ex
 	}
 }
 
+/** Create a constant expression. */
+static struct bfs_expr *opt_const(bool value) {
+	static bfs_eval_fn *fns[] = {eval_false, eval_true};
+	static char *fake_args[] = {"-false", "-true"};
+	return bfs_expr_new(fns[value], 1, &fake_args[value]);
+}
+
 /** Extract a child expression, freeing the outer expression. */
 static struct bfs_expr *extract_child_expr(struct bfs_expr *expr, struct bfs_expr **child) {
 	struct bfs_expr *ret = *child;
@@ -457,14 +464,11 @@ static struct bfs_expr *optimize_not_expr(const struct opt_state *state, struct
 
 	int optlevel = state->ctx->optlevel;
 	if (optlevel >= 1) {
-		if (rhs == &bfs_true) {
-			opt_debug(state, 1, "constant propagation: %pe <==> %pe\n", expr, &bfs_false);
+		if (rhs->eval_fn == eval_true || rhs->eval_fn == eval_false) {
+			struct bfs_expr *ret = opt_const(rhs->eval_fn == eval_false);
+			opt_debug(state, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
 			bfs_expr_free(expr);
-			return &bfs_false;
-		} else if (rhs == &bfs_false) {
-			opt_debug(state, 1, "constant propagation: %pe <==> %pe\n", expr, &bfs_true);
-			bfs_expr_free(expr);
-			return &bfs_true;
+			return ret;
 		} else if (rhs->eval_fn == eval_not) {
 			opt_debug(state, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
 			return extract_child_expr(expr, &rhs->rhs);
@@ -514,17 +518,17 @@ static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct
 	const struct bfs_ctx *ctx = state->ctx;
 	int optlevel = ctx->optlevel;
 	if (optlevel >= 1) {
-		if (lhs == &bfs_true) {
+		if (lhs->eval_fn == eval_true) {
 			opt_debug(state, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
 			return extract_child_expr(expr, &expr->rhs);
-		} else if (rhs == &bfs_true) {
+		} else if (rhs->eval_fn == eval_true) {
 			opt_debug(state, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (lhs->always_false) {
 			opt_debug(state, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
 			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
-		} else if (lhs->always_true && rhs == &bfs_false) {
+		} else if (lhs->always_true && rhs->eval_fn == eval_false) {
 			bool debug = opt_debug(state, 1, "strength reduction: %pe <==> ", expr);
 			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
 			ret = negate_expr(ret, &fake_not_arg);
@@ -532,7 +536,7 @@ static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct
 				cfprintf(ctx->cerr, "%pe\n", ret);
 			}
 			return ret;
-		} else if (optlevel >= 2 && lhs->pure && rhs == &bfs_false) {
+		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_false) {
 			opt_debug(state, 2, "purity: %pe <==> %pe\n", expr, rhs);
 			opt_warning(state, expr->lhs, "The result of this expression is ignored.\n\n");
 			return extract_child_expr(expr, &expr->rhs);
@@ -589,13 +593,13 @@ static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct b
 			opt_debug(state, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
 			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
-		} else if (lhs == &bfs_false) {
+		} else if (lhs->eval_fn == eval_false) {
 			opt_debug(state, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
 			return extract_child_expr(expr, &expr->rhs);
-		} else if (rhs == &bfs_false) {
+		} else if (rhs->eval_fn == eval_false) {
 			opt_debug(state, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
-		} else if (lhs->always_false && rhs == &bfs_true) {
+		} else if (lhs->always_false && rhs->eval_fn == eval_true) {
 			bool debug = opt_debug(state, 1, "strength reduction: %pe <==> ", expr);
 			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
 			ret = negate_expr(ret, &fake_not_arg);
@@ -603,7 +607,7 @@ static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct b
 				cfprintf(ctx->cerr, "%pe\n", ret);
 			}
 			return ret;
-		} else if (optlevel >= 2 && lhs->pure && rhs == &bfs_true) {
+		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_true) {
 			opt_debug(state, 2, "purity: %pe <==> %pe\n", expr, rhs);
 			opt_warning(state, expr->lhs, "The result of this expression is ignored.\n\n");
 			return extract_child_expr(expr, &expr->rhs);
@@ -667,11 +671,12 @@ static struct bfs_expr *ignore_result(const struct opt_state *state, struct bfs_
 			}
 		}
 
-		if (optlevel >= 2 && expr->pure && expr != &bfs_false) {
-			opt_debug(state, 2, "ignored result: %pe --> %pe\n", expr, &bfs_false);
+		if (optlevel >= 2 && expr->pure && expr->eval_fn != eval_false) {
+			struct bfs_expr *ret = opt_const(false);
+			opt_debug(state, 2, "ignored result: %pe --> %pe\n", expr, ret);
 			opt_warning(state, expr, "The result of this expression is ignored.\n\n");
 			bfs_expr_free(expr);
-			expr = &bfs_false;
+			return ret;
 		}
 	}
 
@@ -693,8 +698,8 @@ static struct bfs_expr *optimize_comma_expr(const struct opt_state *state, struc
 			opt_debug(state, 1, "reachability: %pe <==> %pe\n", expr, lhs);
 			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
-		} else if ((lhs->always_true && rhs == &bfs_true)
-			   || (lhs->always_false && rhs == &bfs_false)) {
+		} else if ((lhs->always_true && rhs->eval_fn == eval_true)
+			   || (lhs->always_false && rhs->eval_fn == eval_false)) {
 			opt_debug(state, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (optlevel >= 2 && lhs->pure) {
@@ -835,11 +840,11 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 	state->facts_when_false = state->facts;
 
 	if (optlevel >= 2 && facts_are_impossible(&state->facts)) {
-		opt_debug(state, 2, "reachability: %pe --> %pe\n", expr, &bfs_false);
+		struct bfs_expr *ret = opt_const(false);
+		opt_debug(state, 2, "reachability: %pe --> %pe\n", expr, ret);
 		opt_warning(state, expr, "This expression is unreachable.\n\n");
 		bfs_expr_free(expr);
-		expr = &bfs_false;
-		goto done;
+		return ret;
 	}
 
 	if (!bfs_expr_has_children(expr) && !expr->pure) {
@@ -893,7 +898,7 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 	}
 
 	if (!expr) {
-		goto done;
+		return NULL;
 	}
 
 	if (bfs_expr_has_children(expr)) {
@@ -918,33 +923,34 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		set_facts_impossible(&state->facts_when_true);
 	}
 
-	if (optlevel < 2 || expr == &bfs_true || expr == &bfs_false) {
-		goto done;
+	if (optlevel < 2 || expr->eval_fn == eval_true || expr->eval_fn == eval_false) {
+		return expr;
 	}
 
 	if (facts_are_impossible(&state->facts_when_true)) {
 		if (expr->pure) {
-			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, &bfs_false);
+			struct bfs_expr *ret = opt_const(false);
 			opt_warning(state, expr, "This expression is always false.\n\n");
+			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, ret);
 			bfs_expr_free(expr);
-			expr = &bfs_false;
+			return ret;
 		} else {
 			expr->always_false = true;
 			expr->probability = 0.0;
 		}
 	} else if (facts_are_impossible(&state->facts_when_false)) {
 		if (expr->pure) {
-			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, &bfs_true);
+			struct bfs_expr *ret = opt_const(true);
+			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, ret);
 			opt_warning(state, expr, "This expression is always true.\n\n");
 			bfs_expr_free(expr);
-			expr = &bfs_true;
+			return ret;
 		} else {
 			expr->always_true = true;
 			expr->probability = 1.0;
 		}
 	}
 
-done:
 	return expr;
 }
 
diff --git a/src/parse.c b/src/parse.c
index 2136bb5..16132f3 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -73,45 +73,6 @@ static char *fake_true_arg = "-true";
 #define STAT_COST   1000.0
 #define PRINT_COST 20000.0
 
-struct bfs_expr bfs_true = {
-	.eval_fn = eval_true,
-	.argc = 1,
-	.argv = &fake_true_arg,
-	.pure = true,
-	.always_true = true,
-	.cost = FAST_COST,
-	.probability = 1.0,
-};
-
-struct bfs_expr bfs_false = {
-	.eval_fn = eval_false,
-	.argc = 1,
-	.argv = &fake_false_arg,
-	.pure = true,
-	.always_false = true,
-	.cost = FAST_COST,
-	.probability = 0.0,
-};
-
-void bfs_expr_free(struct bfs_expr *expr) {
-	if (!expr || expr == &bfs_true || expr == &bfs_false) {
-		return;
-	}
-
-	if (bfs_expr_has_children(expr)) {
-		bfs_expr_free(expr->rhs);
-		bfs_expr_free(expr->lhs);
-	} else if (expr->eval_fn == eval_exec) {
-		bfs_exec_free(expr->exec);
-	} else if (expr->eval_fn == eval_fprintf) {
-		bfs_printf_free(expr->printf);
-	} else if (expr->eval_fn == eval_regex) {
-		bfs_regfree(expr->regex);
-	}
-
-	free(expr);
-}
-
 struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	struct bfs_expr *expr = malloc(sizeof(*expr));
 	if (!expr) {
@@ -124,16 +85,29 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	expr->argv = argv;
 	expr->persistent_fds = 0;
 	expr->ephemeral_fds = 0;
-	expr->pure = false;
-	expr->always_true = false;
-	expr->always_false = false;
 	expr->cost = FAST_COST;
-	expr->probability = 0.5;
 	expr->evaluations = 0;
 	expr->successes = 0;
 	expr->elapsed.tv_sec = 0;
 	expr->elapsed.tv_nsec = 0;
 
+	if (eval_fn == eval_true) {
+		expr->pure = true;
+		expr->always_true = true;
+		expr->always_false = false;
+		expr->probability = 1.0;
+	} else if (eval_fn == eval_false) {
+		expr->pure = true;
+		expr->always_true = false;
+		expr->always_false = true;
+		expr->probability = 0.0;
+	} else {
+		expr->pure = false;
+		expr->always_true = false;
+		expr->always_false = false;
+		expr->probability = 0.5;
+	}
+
 	// Prevent bfs_expr_free() from freeing uninitialized pointers on error paths
 	if (bfs_expr_has_children(expr)) {
 		expr->lhs = NULL;
@@ -149,6 +123,37 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	return expr;
 }
 
+bool bfs_expr_has_children(const struct bfs_expr *expr) {
+	return expr->eval_fn == eval_and
+		|| expr->eval_fn == eval_or
+		|| expr->eval_fn == eval_not
+		|| expr->eval_fn == eval_comma;
+}
+
+bool bfs_expr_never_returns(const struct bfs_expr *expr) {
+	// Expressions that never return are vacuously both always true and always false
+	return expr->always_true && expr->always_false;
+}
+
+void bfs_expr_free(struct bfs_expr *expr) {
+	if (!expr) {
+		return;
+	}
+
+	if (bfs_expr_has_children(expr)) {
+		bfs_expr_free(expr->rhs);
+		bfs_expr_free(expr->lhs);
+	} else if (expr->eval_fn == eval_exec) {
+		bfs_exec_free(expr->exec);
+	} else if (expr->eval_fn == eval_fprintf) {
+		bfs_printf_free(expr->printf);
+	} else if (expr->eval_fn == eval_regex) {
+		bfs_regfree(expr->regex);
+	}
+
+	free(expr);
+}
+
 /**
  * Create a new unary expression.
  */
@@ -193,18 +198,6 @@ static struct bfs_expr *new_binary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *l
 	return expr;
 }
 
-bool bfs_expr_has_children(const struct bfs_expr *expr) {
-	return expr->eval_fn == eval_and
-		|| expr->eval_fn == eval_or
-		|| expr->eval_fn == eval_not
-		|| expr->eval_fn == eval_comma;
-}
-
-bool bfs_expr_never_returns(const struct bfs_expr *expr) {
-	// Expressions that never return are vacuously both always true and always false
-	return expr->always_true && expr->always_false;
-}
-
 /**
  * Set an expression to always return true.
  */
@@ -762,8 +755,8 @@ static bool looks_like_icmp(const char *str) {
  * Parse a single flag.
  */
 static struct bfs_expr *parse_flag(struct parser_state *state, size_t argc) {
-	parser_advance(state, T_FLAG, argc);
-	return &bfs_true;
+	char **argv = parser_advance(state, T_FLAG, argc);
+	return bfs_expr_new(eval_true, argc, argv);
 }
 
 /**
@@ -773,12 +766,26 @@ static struct bfs_expr *parse_nullary_flag(struct parser_state *state) {
 	return parse_flag(state, 1);
 }
 
+/**
+ * Parse a flag that takes a value.
+ */
+static struct bfs_expr *parse_unary_flag(struct parser_state *state) {
+	const char *arg = state->argv[0];
+	const char *value = state->argv[1];
+	if (!value) {
+		parse_error(state, "${cyn}%s${rs} needs a value.\n", arg);
+		return NULL;
+	}
+
+	return parse_flag(state, 2);
+}
+
 /**
  * Parse a single option.
  */
 static struct bfs_expr *parse_option(struct parser_state *state, size_t argc) {
-	parser_advance(state, T_OPTION, argc);
-	return &bfs_true;
+	char **argv = parser_advance(state, T_OPTION, argc);
+	return bfs_expr_new(eval_true, argc, argv);
 }
 
 /**
@@ -792,6 +799,13 @@ static struct bfs_expr *parse_nullary_option(struct parser_state *state) {
  * Parse an option that takes a value.
  */
 static struct bfs_expr *parse_unary_option(struct parser_state *state) {
+	const char *arg = state->argv[0];
+	const char *value = state->argv[1];
+	if (!value) {
+		parse_error(state, "${blu}%s${rs} needs a value.\n", arg);
+		return NULL;
+	}
+
 	return parse_option(state, 2);
 }
 
@@ -929,19 +943,16 @@ static bool parse_debug_flag(const char *flag, size_t len, const char *expected)
 static struct bfs_expr *parse_debug(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_ctx *ctx = state->ctx;
 
-	const char *arg = state->argv[0];
-	const char *flags = state->argv[1];
-	if (!flags) {
-		parse_error(state, "${cyn}%s${rs} needs a flag.\n\n", arg);
+	struct bfs_expr *expr = parse_unary_flag(state);
+	if (!expr) {
+		cfprintf(ctx->cerr, "\n");
 		debug_help(ctx->cerr);
 		return NULL;
 	}
 
-	parser_advance(state, T_FLAG, 1);
-
 	bool unrecognized = false;
 
-	for (const char *flag = flags, *next; flag; flag = next) {
+	for (const char *flag = expr->argv[1], *next; flag; flag = next) {
 		size_t len = strcspn(flag, ",");
 		if (flag[len]) {
 			next = flag + len + 1;
@@ -952,6 +963,7 @@ static struct bfs_expr *parse_debug(struct parser_state *state, int arg1, int ar
 		if (parse_debug_flag(flag, len, "help")) {
 			debug_help(ctx->cout);
 			state->just_info = true;
+			bfs_expr_free(expr);
 			return NULL;
 		} else if (parse_debug_flag(flag, len, "all")) {
 			ctx->debug = DEBUG_ALL;
@@ -969,7 +981,7 @@ static struct bfs_expr *parse_debug(struct parser_state *state, int arg1, int ar
 		if (DEBUG_ALL & i) {
 			ctx->debug |= i;
 		} else {
-			if (parse_warning(state, "Unrecognized debug flag ${bld}")) {
+			if (parse_expr_warning(state, expr, "Unrecognized debug flag ${bld}")) {
 				fwrite(flag, 1, len, stderr);
 				cfprintf(ctx->cerr, "${rs}.\n\n");
 				unrecognized = true;
@@ -982,27 +994,32 @@ static struct bfs_expr *parse_debug(struct parser_state *state, int arg1, int ar
 		cfprintf(ctx->cerr, "\n");
 	}
 
-	parser_advance(state, T_FLAG, 1);
-	return &bfs_true;
+	return expr;
 }
 
 /**
  * Parse -On.
  */
 static struct bfs_expr *parse_optlevel(struct parser_state *state, int arg1, int arg2) {
+	struct bfs_expr *expr = parse_nullary_flag(state);
+	if (!expr) {
+		return NULL;
+	}
+
 	int *optlevel = &state->ctx->optlevel;
 
-	if (strcmp(state->argv[0], "-Ofast") == 0) {
+	if (strcmp(expr->argv[0], "-Ofast") == 0) {
 		*optlevel = 4;
-	} else if (!parse_int(state, state->argv, state->argv[0] + 2, optlevel, IF_INT | IF_UNSIGNED)) {
+	} else if (!parse_int(state, expr->argv, expr->argv[0] + 2, optlevel, IF_INT | IF_UNSIGNED)) {
+		bfs_expr_free(expr);
 		return NULL;
 	}
 
 	if (*optlevel > 4) {
-		parse_warning(state, "${cyn}-O${bld}%s${rs} is the same as ${cyn}-O${bld}4${rs}.\n\n", state->argv[0] + 2);
+		parse_expr_warning(state, expr, "${cyn}-O${bld}%s${rs} is the same as ${cyn}-O${bld}4${rs}.\n\n", state->argv[0] + 2);
 	}
 
-	return parse_nullary_flag(state);
+	return expr;
 }
 
 /**
@@ -1203,12 +1220,18 @@ static struct bfs_expr *parse_capable(struct parser_state *state, int flag, int
  * Parse -(no)?color.
  */
 static struct bfs_expr *parse_color(struct parser_state *state, int color, int arg2) {
+	struct bfs_expr *expr = parse_nullary_option(state);
+	if (!expr) {
+		return NULL;
+	}
+
 	struct bfs_ctx *ctx = state->ctx;
 	struct colors *colors = ctx->colors;
 
 	if (color) {
 		if (!colors) {
-			parse_error(state, "%s.\n", strerror(ctx->colors_error));
+			parse_expr_error(state, expr, "%s.\n", strerror(ctx->colors_error));
+			bfs_expr_free(expr);
 			return NULL;
 		}
 
@@ -1221,15 +1244,14 @@ static struct bfs_expr *parse_color(struct parser_state *state, int color, int a
 		ctx->cerr->colors = NULL;
 	}
 
-	return parse_nullary_option(state);
+	return expr;
 }
 
 /**
  * Parse -{false,true}.
  */
 static struct bfs_expr *parse_const(struct parser_state *state, int value, int arg2) {
-	parser_advance(state, T_TEST, 1);
-	return value ? &bfs_true : &bfs_false;
+	return parse_nullary_test(state, value ? eval_true : eval_false);
 }
 
 /**
@@ -1295,20 +1317,20 @@ static struct bfs_expr *parse_depth_n(struct parser_state *state, int arg1, int
  * Parse -{min,max}depth N.
  */
 static struct bfs_expr *parse_depth_limit(struct parser_state *state, int is_min, int arg2) {
-	struct bfs_ctx *ctx = state->ctx;
-	const char *arg = state->argv[0];
-	const char *value = state->argv[1];
-	if (!value) {
-		parse_error(state, "${blu}%s${rs} needs a value.\n", arg);
+	struct bfs_expr *expr = parse_unary_option(state);
+	if (!expr) {
 		return NULL;
 	}
 
+	struct bfs_ctx *ctx = state->ctx;
 	int *depth = is_min ? &ctx->mindepth : &ctx->maxdepth;
-	if (!parse_int(state, &state->argv[1], value, depth, IF_INT | IF_UNSIGNED)) {
+	char **arg = &expr->argv[1];
+	if (!parse_int(state, arg, *arg, depth, IF_INT | IF_UNSIGNED)) {
+		bfs_expr_free(expr);
 		return NULL;
 	}
 
-	return parse_unary_option(state);
+	return expr;
 }
 
 /**
@@ -1398,33 +1420,30 @@ static struct bfs_expr *parse_exit(struct parser_state *state, int arg1, int arg
  * Parse -f PATH.
  */
 static struct bfs_expr *parse_f(struct parser_state *state, int arg1, int arg2) {
-	const char *path = state->argv[1];
-	if (!path) {
-		parse_error(state, "${cyn}-f${rs} requires a path.\n");
+	struct bfs_expr *expr = parse_unary_flag(state);
+	if (!expr) {
 		return NULL;
 	}
 
-	if (parse_root(state, path) != 0) {
+	if (parse_root(state, expr->argv[1]) != 0) {
+		bfs_expr_free(expr);
 		return NULL;
 	}
 
-	parser_advance(state, T_FLAG, 1);
-	parser_advance(state, T_PATH, 1);
-	return &bfs_true;
+	return expr;
 }
 
 /**
  * Parse -files0-from PATH.
  */
 static struct bfs_expr *parse_files0_from(struct parser_state *state, int arg1, int arg2) {
-	const char *arg = state->argv[0];
-	const char *from = state->argv[1];
-	if (!from) {
-		parse_error(state, "${blu}%s${rs} requires a path.\n", arg);
+	struct bfs_expr *expr = parse_unary_option(state);
+	if (!expr) {
 		return NULL;
 	}
 
-	state->files0_arg = parser_advance(state, T_OPTION, 1);
+	state->files0_arg = expr->argv;
+	const char *from = expr->argv[1];
 
 	FILE *file;
 	if (strcmp(from, "-") == 0) {
@@ -1433,27 +1452,24 @@ static struct bfs_expr *parse_files0_from(struct parser_state *state, int arg1,
 		file = xfopen(from, O_RDONLY | O_CLOEXEC);
 	}
 	if (!file) {
-		parse_error(state, "%m.\n");
-		return NULL;
+		parse_expr_error(state, expr, "%m.\n");
+		goto fail;
 	}
 
-	struct bfs_expr *expr = &bfs_true;
-
 	while (true) {
 		char *path = xgetdelim(file, '\0');
 		if (!path) {
 			if (errno) {
-				parse_error(state, "%m.\n");
-				expr = NULL;
+				goto fail;
+			} else {
+				break;
 			}
-			break;
 		}
 
 		int ret = parse_root(state, path);
 		free(path);
 		if (ret != 0) {
-			expr = NULL;
-			break;
+			goto fail;
 		}
 	}
 
@@ -1464,8 +1480,14 @@ static struct bfs_expr *parse_files0_from(struct parser_state *state, int arg1,
 	}
 
 	state->implicit_root = false;
-	parser_advance(state, T_OPTION, 1);
 	return expr;
+
+fail:
+	if (file && file != stdin) {
+		fclose(file);
+	}
+	bfs_expr_free(expr);
+	return NULL;
 }
 
 /**
@@ -1771,12 +1793,17 @@ static struct bfs_expr *parse_ls(struct parser_state *state, int arg1, int arg2)
  * Parse -mount.
  */
 static struct bfs_expr *parse_mount(struct parser_state *state, int arg1, int arg2) {
-	parse_warning(state, "In the future, ${blu}%s${rs} will skip mount points entirely, unlike\n", state->argv[0]);
+	struct bfs_expr *expr = parse_nullary_option(state);
+	if (!expr) {
+		return NULL;
+	}
+
+	parse_expr_warning(state, expr, "In the future, ${blu}%s${rs} will skip mount points entirely, unlike\n", expr->argv[0]);
 	bfs_warning(state->ctx, "${blu}-xdev${rs}, due to http://austingroupbugs.net/view.php?id=1133.\n\n");
 
 	state->ctx->flags |= BFTW_PRUNE_MOUNTS;
 	state->mount_arg = state->argv;
-	return parse_nullary_option(state);
+	return expr;
 }
 
 /**
@@ -1814,8 +1841,8 @@ static struct bfs_expr *parse_fnmatch(const struct parser_state *state, struct b
 	}
 	if (i % 2 != 0) {
 		parse_expr_warning(state, expr, "Unescaped trailing backslash.\n\n");
-		bfs_expr_free(expr);
-		return &bfs_false;
+		expr->eval_fn = eval_false;
+		return expr;
 	}
 
 	expr->cost = 400.0;
@@ -2009,8 +2036,7 @@ static struct bfs_expr *parse_nohidden(struct parser_state *state, int arg1, int
 		return NULL;
 	}
 
-	parser_advance(state, T_OPTION, 1);
-	return &bfs_true;
+	return parse_nullary_option(state);
 }
 
 /**
@@ -2430,16 +2456,14 @@ static struct bfs_expr *parse_regextype(struct parser_state *state, int arg1, in
 	struct bfs_ctx *ctx = state->ctx;
 	CFILE *cfile = ctx->cerr;
 
-	const char *arg = state->argv[0];
-	const char *type = state->argv[1];
-	if (!type) {
-		parse_error(state, "${blu}%s${rs} needs a value.\n\n", arg);
+	struct bfs_expr *expr = parse_unary_option(state);
+	if (!expr) {
+		cfprintf(cfile, "\n");
 		goto list_types;
 	}
 
-	parser_advance(state, T_OPTION, 1);
-
 	// See https://www.gnu.org/software/gnulib/manual/html_node/Predefined-Syntaxes.html
+	const char *type = expr->argv[1];
 	if (strcmp(type, "posix-basic") == 0
 	    || strcmp(type, "ed") == 0
 	    || strcmp(type, "sed") == 0) {
@@ -2457,12 +2481,11 @@ static struct bfs_expr *parse_regextype(struct parser_state *state, int arg1, in
 		cfile = ctx->cout;
 		goto list_types;
 	} else {
-		parse_error(state, "Unsupported regex type.\n\n");
+		parse_expr_error(state, expr, "Unsupported regex type.\n\n");
 		goto list_types;
 	}
 
-	parser_advance(state, T_OPTION, 1);
-	return &bfs_true;
+	return expr;
 
 list_types:
 	cfprintf(cfile, "Supported types are:\n\n");
@@ -2474,6 +2497,8 @@ list_types:
 	cfprintf(cfile, "  ${bld}grep${rs}:           Like ${grn}grep${rs}\n");
 #endif
 	cfprintf(cfile, "  ${bld}sed${rs}:            Like ${grn}sed${rs} (same as ${bld}posix-basic${rs})\n");
+
+	bfs_expr_free(expr);
 	return NULL;
 }
 
@@ -2516,15 +2541,13 @@ static struct bfs_expr *parse_search_strategy(struct parser_state *state, int ar
 	struct bfs_ctx *ctx = state->ctx;
 	CFILE *cfile = ctx->cerr;
 
-	const char *flag = state->argv[0];
-	const char *arg = state->argv[1];
-	if (!arg) {
-		parse_error(state, "${cyn}%s${rs} needs an argument.\n\n", flag);
+	struct bfs_expr *expr = parse_unary_flag(state);
+	if (!expr) {
+		cfprintf(cfile, "\n");
 		goto list_strategies;
 	}
 
-	parser_advance(state, T_FLAG, 1);
-
+	const char *arg = expr->argv[1];
 	if (strcmp(arg, "bfs") == 0) {
 		ctx->strategy = BFTW_BFS;
 	} else if (strcmp(arg, "dfs") == 0) {
@@ -2538,12 +2561,11 @@ static struct bfs_expr *parse_search_strategy(struct parser_state *state, int ar
 		cfile = ctx->cout;
 		goto list_strategies;
 	} else {
-		parse_error(state, "Unrecognized search strategy.\n\n");
+		parse_expr_error(state, expr, "Unrecognized search strategy.\n\n");
 		goto list_strategies;
 	}
 
-	parser_advance(state, T_FLAG, 1);
-	return &bfs_true;
+	return expr;
 
 list_strategies:
 	cfprintf(cfile, "Supported search strategies:\n\n");
@@ -2551,6 +2573,8 @@ list_strategies:
 	cfprintf(cfile, "  ${bld}dfs${rs}: depth-first search\n");
 	cfprintf(cfile, "  ${bld}ids${rs}: iterative deepening search\n");
 	cfprintf(cfile, "  ${bld}eds${rs}: exponential deepening search\n");
+
+	bfs_expr_free(expr);
 	return NULL;
 }
 
@@ -3456,7 +3480,7 @@ static struct bfs_expr *parse_factor(struct parser_state *state) {
 			return NULL;
 		}
 
-		parser_advance(state, T_OPERATOR, 1);
+		char **argv = parser_advance(state, T_OPERATOR, 1);
 		state->excluding = true;
 
 		struct bfs_expr *factor = parse_factor(state);
@@ -3470,7 +3494,7 @@ static struct bfs_expr *parse_factor(struct parser_state *state) {
 			return NULL;
 		}
 
-		return &bfs_true;
+		return bfs_expr_new(eval_true, state->argv - argv, argv);
 	} else if (strcmp(arg, "!") == 0 || strcmp(arg, "-not") == 0) {
 		char **argv = parser_advance(state, T_OPERATOR, 1);
 
@@ -3612,12 +3636,14 @@ static struct bfs_expr *parse_whole_expr(struct parser_state *state) {
 		return NULL;
 	}
 
-	struct bfs_expr *expr = &bfs_true;
+	struct bfs_expr *expr;
 	if (state->argv[0]) {
 		expr = parse_expr(state);
-		if (!expr) {
-			return NULL;
-		}
+	} else {
+		expr = bfs_expr_new(eval_true, 1, &fake_true_arg);
+	}
+	if (!expr) {
+		return NULL;
 	}
 
 	if (state->argv[0]) {
@@ -3804,7 +3830,7 @@ void bfs_ctx_dump(const struct bfs_ctx *ctx, enum debug_flags flag) {
 
 	fputs("\n", stderr);
 
-	if (ctx->exclude != &bfs_false) {
+	if (ctx->exclude->eval_fn != eval_false) {
 		bfs_debug(ctx, flag, "(${red}-exclude${rs}\n");
 		dump_expr_multiline(ctx, flag, ctx->exclude, 1, 1);
 	}
@@ -3910,7 +3936,11 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 		ctx->strategy = BFTW_DFS;
 	}
 
-	ctx->exclude = &bfs_false;
+	ctx->exclude = bfs_expr_new(eval_false, 1, &fake_false_arg);
+	if (!ctx->exclude) {
+		goto fail;
+	}
+
 	ctx->expr = parse_whole_expr(&state);
 	if (!ctx->expr) {
 		if (state.just_info) {
-- 
cgit v1.2.3


From d1e532ed839c1b2be093c88006fcf4cd3d11805d Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Mon, 5 Dec 2022 14:18:53 -0500
Subject: expr: Rename bfs_expr_has_children() to _is_parent()

---
 src/color.c |  2 +-
 src/diag.c  |  2 +-
 src/eval.c  |  4 ++--
 src/expr.h  |  2 +-
 src/opt.c   |  6 +++---
 src/parse.c | 12 ++++++------
 6 files changed, 14 insertions(+), 14 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/color.c b/src/color.c
index 94fcac8..8d32c6c 100644
--- a/src/color.c
+++ b/src/color.c
@@ -888,7 +888,7 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 	const struct bfs_expr *lhs = NULL;
 	const struct bfs_expr *rhs = NULL;
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		lhs = expr->lhs;
 		rhs = expr->rhs;
 
diff --git a/src/diag.c b/src/diag.c
index c5e139e..a0c11f2 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -125,7 +125,7 @@ static bool highlight_expr_recursive(const struct bfs_ctx *ctx, const struct bfs
 		}
 	}
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		ret |= highlight_expr_recursive(ctx, expr->lhs, args);
 		ret |= highlight_expr_recursive(ctx, expr->rhs, args);
 	}
diff --git a/src/eval.c b/src/eval.c
index 4c9d807..e3257ce 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -387,7 +387,7 @@ static int eval_exec_finish(const struct bfs_expr *expr, const struct bfs_ctx *c
 			}
 			ret = -1;
 		}
-	} else if (bfs_expr_has_children(expr)) {
+	} else if (bfs_expr_is_parent(expr)) {
 		if (expr->lhs && eval_exec_finish(expr->lhs, ctx) != 0) {
 			ret = -1;
 		}
@@ -1557,7 +1557,7 @@ static bool eval_must_buffer(const struct bfs_expr *expr) {
 		return true;
 	}
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		if (expr->lhs && eval_must_buffer(expr->lhs)) {
 			return true;
 		}
diff --git a/src/expr.h b/src/expr.h
index e541d8e..a52007a 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -210,7 +210,7 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval, size_t argc, char **argv);
 /**
  * @return Whether the expression has child expressions.
  */
-bool bfs_expr_has_children(const struct bfs_expr *expr);
+bool bfs_expr_is_parent(const struct bfs_expr *expr);
 
 /**
  * @return Whether expr is known to always quit.
diff --git a/src/opt.c b/src/opt.c
index 441c611..56d4102 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -847,7 +847,7 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		return ret;
 	}
 
-	if (!bfs_expr_has_children(expr) && !expr->pure) {
+	if (!bfs_expr_is_parent(expr) && !expr->pure) {
 		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
 	}
 
@@ -901,7 +901,7 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		return NULL;
 	}
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		struct bfs_expr *lhs = expr->lhs;
 		struct bfs_expr *rhs = expr->rhs;
 		if (rhs) {
@@ -980,7 +980,7 @@ static bool reorder_expr(const struct opt_state *state, struct bfs_expr *expr, f
  *         Whether any subexpression was reordered.
  */
 static bool reorder_expr_recursive(const struct opt_state *state, struct bfs_expr *expr) {
-	if (!bfs_expr_has_children(expr)) {
+	if (!bfs_expr_is_parent(expr)) {
 		return false;
 	}
 
diff --git a/src/parse.c b/src/parse.c
index a858a4c..320e165 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -109,7 +109,7 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	}
 
 	// Prevent bfs_expr_free() from freeing uninitialized pointers on error paths
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		expr->lhs = NULL;
 		expr->rhs = NULL;
 	} else if (eval_fn == eval_exec) {
@@ -123,7 +123,7 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	return expr;
 }
 
-bool bfs_expr_has_children(const struct bfs_expr *expr) {
+bool bfs_expr_is_parent(const struct bfs_expr *expr) {
 	return expr->eval_fn == eval_and
 		|| expr->eval_fn == eval_or
 		|| expr->eval_fn == eval_not
@@ -140,7 +140,7 @@ void bfs_expr_free(struct bfs_expr *expr) {
 		return;
 	}
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		bfs_expr_free(expr->rhs);
 		bfs_expr_free(expr->lhs);
 	} else if (expr->eval_fn == eval_exec) {
@@ -166,7 +166,7 @@ static struct bfs_expr *new_unary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *rh
 
 	expr->lhs = NULL;
 	expr->rhs = rhs;
-	assert(bfs_expr_has_children(expr));
+	assert(bfs_expr_is_parent(expr));
 
 	expr->persistent_fds = rhs->persistent_fds;
 	expr->ephemeral_fds = rhs->ephemeral_fds;
@@ -186,7 +186,7 @@ static struct bfs_expr *new_binary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *l
 
 	expr->lhs = lhs;
 	expr->rhs = rhs;
-	assert(bfs_expr_has_children(expr));
+	assert(bfs_expr_is_parent(expr));
 
 	expr->persistent_fds = lhs->persistent_fds + rhs->persistent_fds;
 	if (lhs->ephemeral_fds > rhs->ephemeral_fds) {
@@ -3722,7 +3722,7 @@ static void dump_expr_multiline(const struct bfs_ctx *ctx, enum debug_flags flag
 		cfprintf(ctx->cerr, "  ");
 	}
 
-	if (bfs_expr_has_children(expr)) {
+	if (bfs_expr_is_parent(expr)) {
 		cfprintf(ctx->cerr, "(${red}%s${rs}\n", expr->argv[0]);
 		if (expr->lhs) {
 			dump_expr_multiline(ctx, flag, expr->lhs, indent + 1, 0);
-- 
cgit v1.2.3


From ededa3ed1cf0d02fcdb9a42d44d46a84fec1c58e Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 8 Dec 2022 16:43:29 -0500
Subject: opt: Pass a va_list to bfs_vwarning(), not bfs_warning()

Luckily none of the callers actually pass any arguments.
---
 src/opt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 56d4102..3250331 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -339,7 +339,7 @@ static void opt_warning(const struct opt_state *state, const struct bfs_expr *ex
 	if (bfs_expr_warning(state->ctx, expr)) {
 		va_list args;
 		va_start(args, format);
-		bfs_warning(state->ctx, format, args);
+		bfs_vwarning(state->ctx, format, args);
 		va_end(args);
 	}
 }
-- 
cgit v1.2.3


From fcbd5d315ec71e1890a2d8a0d7e4107bfbb7bca6 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 16:41:34 -0500
Subject: opt: Use a table to look up optimizer functions

---
 src/opt.c | 115 ++++++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 71 insertions(+), 44 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 3250331..6ec3414 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -746,19 +746,6 @@ static void infer_pred_facts(struct opt_state *state, enum pred_type pred) {
 	constrain_pred(&state->facts_when_false.preds[pred], false);
 }
 
-/** Infer data flow facts about an -{execut,read,writ}able expression. */
-static void infer_access_facts(struct opt_state *state, const struct bfs_expr *expr) {
-	if (expr->num & R_OK) {
-		infer_pred_facts(state, READABLE_PRED);
-	}
-	if (expr->num & W_OK) {
-		infer_pred_facts(state, WRITABLE_PRED);
-	}
-	if (expr->num & X_OK) {
-		infer_pred_facts(state, EXECUTABLE_PRED);
-	}
-}
-
 /** Infer data flow facts about an icmp-style ([+-]N) expression. */
 static void infer_icmp_facts(struct opt_state *state, const struct bfs_expr *expr, enum range_type type) {
 	struct range *range_when_true = &state->facts_when_true.ranges[type];
@@ -786,8 +773,22 @@ static void infer_icmp_facts(struct opt_state *state, const struct bfs_expr *exp
 	}
 }
 
-/** Infer data flow facts about a -gid expression. */
-static void infer_gid_facts(struct opt_state *state, const struct bfs_expr *expr) {
+/** Optimize -{execut,read,writ}able. */
+static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr *expr) {
+	if (expr->num & R_OK) {
+		infer_pred_facts(state, READABLE_PRED);
+	}
+	if (expr->num & W_OK) {
+		infer_pred_facts(state, WRITABLE_PRED);
+	}
+	if (expr->num & X_OK) {
+		infer_pred_facts(state, EXECUTABLE_PRED);
+	}
+	return expr;
+}
+
+/** Optimize -gid. */
+static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
 	infer_icmp_facts(state, expr, GID_RANGE);
 
 	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
@@ -798,10 +799,12 @@ static void infer_gid_facts(struct opt_state *state, const struct bfs_expr *expr
 			constrain_pred(&state->facts_when_true.preds[NOGROUP_PRED], nogroup);
 		}
 	}
+
+	return expr;
 }
 
-/** Infer data flow facts about a -uid expression. */
-static void infer_uid_facts(struct opt_state *state, const struct bfs_expr *expr) {
+/** Optimize -uid. */
+static struct bfs_expr *optimize_uid(struct opt_state *state, struct bfs_expr *expr) {
 	infer_icmp_facts(state, expr, UID_RANGE);
 
 	struct range *range = &state->facts_when_true.ranges[UID_RANGE];
@@ -812,25 +815,68 @@ static void infer_uid_facts(struct opt_state *state, const struct bfs_expr *expr
 			constrain_pred(&state->facts_when_true.preds[NOUSER_PRED], nouser);
 		}
 	}
+
+	return expr;
 }
 
-/** Infer data flow facts about a -samefile expression. */
-static void infer_samefile_facts(struct opt_state *state, const struct bfs_expr *expr) {
+/** Optimize -samefile. */
+static struct bfs_expr *optimize_samefile(struct opt_state *state, struct bfs_expr *expr) {
 	struct range *range_when_true = &state->facts_when_true.ranges[INUM_RANGE];
 	constrain_min(range_when_true, expr->ino);
 	constrain_max(range_when_true, expr->ino);
+	return expr;
 }
 
-/** Infer data flow facts about a -type expression. */
-static void infer_type_facts(struct opt_state *state, const struct bfs_expr *expr) {
+/** Optimize -type. */
+static struct bfs_expr *optimize_type(struct opt_state *state, struct bfs_expr *expr) {
 	state->facts_when_true.types &= expr->num;
 	state->facts_when_false.types &= ~expr->num;
+	return expr;
 }
 
-/** Infer data flow facts about an -xtype expression. */
-static void infer_xtype_facts(struct opt_state *state, const struct bfs_expr *expr) {
+/** Optimize -xtype. */
+static struct bfs_expr *optimize_xtype(struct opt_state *state, struct bfs_expr *expr) {
 	state->facts_when_true.xtypes &= expr->num;
 	state->facts_when_false.xtypes &= ~expr->num;
+	return expr;
+}
+
+/** Signature for custom optimizer functions. */
+typedef struct bfs_expr *bfs_opt_fn(struct opt_state *state, struct bfs_expr *expr);
+
+/** Table of custom optimizer functions. */
+static const struct {
+	/** The evaluation function this optimizer applies to. */
+	bfs_eval_fn *eval_fn;
+	/** The corresponding optimizer function. */
+	bfs_opt_fn *opt_fn;
+} opt_fns[] = {
+	// Primaries
+	{eval_access,   optimize_access},
+	{eval_gid,      optimize_gid},
+	{eval_samefile, optimize_samefile},
+	{eval_type,     optimize_type},
+	{eval_uid,      optimize_uid},
+	{eval_xtype,    optimize_xtype},
+
+	// Operators
+	{eval_and,   optimize_and_expr_recursive},
+	{eval_comma, optimize_comma_expr_recursive},
+	{eval_not,   optimize_not_expr_recursive},
+	{eval_or,    optimize_or_expr_recursive},
+};
+
+/**
+ * Look up the appropriate optimizer for an expression and call it.
+ */
+static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs_expr *expr) {
+	for (size_t i = 0; i < BFS_COUNTOF(opt_fns); ++i) {
+		if (opt_fns[i].eval_fn == expr->eval_fn) {
+			return opt_fns[i].opt_fn(state, expr);
+		}
+	}
+
+	return expr;
 }
 
 static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
@@ -851,9 +897,7 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
 	}
 
-	if (expr->eval_fn == eval_access) {
-		infer_access_facts(state, expr);
-	} else if (expr->eval_fn == eval_acl) {
+	if (expr->eval_fn == eval_acl) {
 		infer_pred_facts(state, ACL_PRED);
 	} else if (expr->eval_fn == eval_capable) {
 		infer_pred_facts(state, CAPABLE_PRED);
@@ -861,8 +905,6 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		infer_icmp_facts(state, expr, DEPTH_RANGE);
 	} else if (expr->eval_fn == eval_empty) {
 		infer_pred_facts(state, EMPTY_PRED);
-	} else if (expr->eval_fn == eval_gid) {
-		infer_gid_facts(state, expr);
 	} else if (expr->eval_fn == eval_hidden) {
 		infer_pred_facts(state, HIDDEN_PRED);
 	} else if (expr->eval_fn == eval_inum) {
@@ -873,30 +915,15 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		infer_pred_facts(state, NOGROUP_PRED);
 	} else if (expr->eval_fn == eval_nouser) {
 		infer_pred_facts(state, NOUSER_PRED);
-	} else if (expr->eval_fn == eval_samefile) {
-		infer_samefile_facts(state, expr);
 	} else if (expr->eval_fn == eval_size) {
 		infer_icmp_facts(state, expr, SIZE_RANGE);
 	} else if (expr->eval_fn == eval_sparse) {
 		infer_pred_facts(state, SPARSE_PRED);
-	} else if (expr->eval_fn == eval_type) {
-		infer_type_facts(state, expr);
-	} else if (expr->eval_fn == eval_uid) {
-		infer_uid_facts(state, expr);
 	} else if (expr->eval_fn == eval_xattr) {
 		infer_pred_facts(state, XATTR_PRED);
-	} else if (expr->eval_fn == eval_xtype) {
-		infer_xtype_facts(state, expr);
-	} else if (expr->eval_fn == eval_not) {
-		expr = optimize_not_expr_recursive(state, expr);
-	} else if (expr->eval_fn == eval_and) {
-		expr = optimize_and_expr_recursive(state, expr);
-	} else if (expr->eval_fn == eval_or) {
-		expr = optimize_or_expr_recursive(state, expr);
-	} else if (expr->eval_fn == eval_comma) {
-		expr = optimize_comma_expr_recursive(state, expr);
 	}
 
+	expr = optimize_expr_lookup(state, expr);
 	if (!expr) {
 		return NULL;
 	}
-- 
cgit v1.2.3


From 0c0dbcbcdf04e55c2805eb71aecd968ea2ffe1a0 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 16:47:28 -0500
Subject: opt: Use a table for simple predicates

---
 src/opt.c | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 6ec3414..a33ffea 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -841,6 +841,25 @@ static struct bfs_expr *optimize_xtype(struct opt_state *state, struct bfs_expr
 	return expr;
 }
 
+/**
+ * Table of simple predicates.
+ */
+static const struct {
+	/** The evaluation function this optimizer applies to. */
+	bfs_eval_fn *eval_fn;
+	/** The corresponding predicate. */
+	enum pred_type pred;
+} opt_preds[] = {
+	{eval_acl,         ACL_PRED},
+	{eval_capable, CAPABLE_PRED},
+	{eval_empty,     EMPTY_PRED},
+	{eval_hidden,   HIDDEN_PRED},
+	{eval_nogroup, NOGROUP_PRED},
+	{eval_nouser,   NOUSER_PRED},
+	{eval_sparse,   SPARSE_PRED},
+	{eval_xattr,     XATTR_PRED},
+};
+
 /** Signature for custom optimizer functions. */
 typedef struct bfs_expr *bfs_opt_fn(struct opt_state *state, struct bfs_expr *expr);
 
@@ -870,6 +889,13 @@ static const struct {
  * Look up the appropriate optimizer for an expression and call it.
  */
 static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs_expr *expr) {
+	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
+		if (opt_preds[i].eval_fn == expr->eval_fn) {
+			infer_pred_facts(state, opt_preds[i].pred);
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_fns); ++i) {
 		if (opt_fns[i].eval_fn == expr->eval_fn) {
 			return opt_fns[i].opt_fn(state, expr);
@@ -897,30 +923,14 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
 	}
 
-	if (expr->eval_fn == eval_acl) {
-		infer_pred_facts(state, ACL_PRED);
-	} else if (expr->eval_fn == eval_capable) {
-		infer_pred_facts(state, CAPABLE_PRED);
-	} else if (expr->eval_fn == eval_depth) {
+	if (expr->eval_fn == eval_depth) {
 		infer_icmp_facts(state, expr, DEPTH_RANGE);
-	} else if (expr->eval_fn == eval_empty) {
-		infer_pred_facts(state, EMPTY_PRED);
-	} else if (expr->eval_fn == eval_hidden) {
-		infer_pred_facts(state, HIDDEN_PRED);
 	} else if (expr->eval_fn == eval_inum) {
 		infer_icmp_facts(state, expr, INUM_RANGE);
 	} else if (expr->eval_fn == eval_links) {
 		infer_icmp_facts(state, expr, LINKS_RANGE);
-	} else if (expr->eval_fn == eval_nogroup) {
-		infer_pred_facts(state, NOGROUP_PRED);
-	} else if (expr->eval_fn == eval_nouser) {
-		infer_pred_facts(state, NOUSER_PRED);
 	} else if (expr->eval_fn == eval_size) {
 		infer_icmp_facts(state, expr, SIZE_RANGE);
-	} else if (expr->eval_fn == eval_sparse) {
-		infer_pred_facts(state, SPARSE_PRED);
-	} else if (expr->eval_fn == eval_xattr) {
-		infer_pred_facts(state, XATTR_PRED);
 	}
 
 	expr = optimize_expr_lookup(state, expr);
-- 
cgit v1.2.3


From b922add3a5597020a0ad5357b5fc390b3fae709f Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 16:51:33 -0500
Subject: opt: Use a table for simple range comparisons

---
 src/opt.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index a33ffea..50fcd20 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -789,8 +789,6 @@ static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr
 
 /** Optimize -gid. */
 static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
-	infer_icmp_facts(state, expr, GID_RANGE);
-
 	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
 	if (range->min == range->max) {
 		gid_t gid = range->min;
@@ -805,8 +803,6 @@ static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *e
 
 /** Optimize -uid. */
 static struct bfs_expr *optimize_uid(struct opt_state *state, struct bfs_expr *expr) {
-	infer_icmp_facts(state, expr, UID_RANGE);
-
 	struct range *range = &state->facts_when_true.ranges[UID_RANGE];
 	if (range->min == range->max) {
 		uid_t uid = range->min;
@@ -860,6 +856,23 @@ static const struct {
 	{eval_xattr,     XATTR_PRED},
 };
 
+/**
+ * Table of simple range comparisons.
+ */
+static const struct {
+	/** The evaluation function this optimizer applies to. */
+	bfs_eval_fn *eval_fn;
+	/** The corresponding range. */
+	enum range_type range;
+} opt_ranges[] = {
+	{eval_depth, DEPTH_RANGE},
+	{eval_gid,     GID_RANGE},
+	{eval_inum,   INUM_RANGE},
+	{eval_links, LINKS_RANGE},
+	{eval_size,   SIZE_RANGE},
+	{eval_uid,     UID_RANGE},
+};
+
 /** Signature for custom optimizer functions. */
 typedef struct bfs_expr *bfs_opt_fn(struct opt_state *state, struct bfs_expr *expr);
 
@@ -896,6 +909,13 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 		}
 	}
 
+	for (size_t i = 0; i < BFS_COUNTOF(opt_ranges); ++i) {
+		if (opt_ranges[i].eval_fn == expr->eval_fn) {
+			infer_icmp_facts(state, expr, opt_ranges[i].range);
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_fns); ++i) {
 		if (opt_fns[i].eval_fn == expr->eval_fn) {
 			return opt_fns[i].opt_fn(state, expr);
@@ -923,16 +943,6 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
 	}
 
-	if (expr->eval_fn == eval_depth) {
-		infer_icmp_facts(state, expr, DEPTH_RANGE);
-	} else if (expr->eval_fn == eval_inum) {
-		infer_icmp_facts(state, expr, INUM_RANGE);
-	} else if (expr->eval_fn == eval_links) {
-		infer_icmp_facts(state, expr, LINKS_RANGE);
-	} else if (expr->eval_fn == eval_size) {
-		infer_icmp_facts(state, expr, SIZE_RANGE);
-	}
-
 	expr = optimize_expr_lookup(state, expr);
 	if (!expr) {
 		return NULL;
-- 
cgit v1.2.3


From 693b5f60dc9787d9237920cc0c87fe0e010194ee Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 16:59:49 -0500
Subject: opt: Move purity out of the parser

---
 src/opt.c   | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/parse.c | 27 ++-------------------------
 2 files changed, 64 insertions(+), 25 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 50fcd20..934a4b4 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -787,6 +787,18 @@ static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr
 	return expr;
 }
 
+/** Optimize -empty. */
+static struct bfs_expr *optimize_empty(struct opt_state *state, struct bfs_expr *expr) {
+	if (state->ctx->optlevel >= 4) {
+		// Since -empty attempts to open and read directories, it may
+		// have side effects such as reporting permission errors, and
+		// thus shouldn't be re-ordered without aggressive optimizations
+		expr->pure = true;
+	}
+
+	return expr;
+}
+
 /** Optimize -gid. */
 static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
 	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
@@ -832,11 +844,53 @@ static struct bfs_expr *optimize_type(struct opt_state *state, struct bfs_expr *
 
 /** Optimize -xtype. */
 static struct bfs_expr *optimize_xtype(struct opt_state *state, struct bfs_expr *expr) {
+	if (state->ctx->optlevel >= 4) {
+		// Since -xtype dereferences symbolic links, it may have side
+		// effects such as reporting permission errors, and thus
+		// shouldn't be re-ordered without aggressive optimizations
+		expr->pure = true;
+	}
+
 	state->facts_when_true.xtypes &= expr->num;
 	state->facts_when_false.xtypes &= ~expr->num;
 	return expr;
 }
 
+/**
+ * Table of pure expressions.
+ */
+static bfs_eval_fn *const opt_pure[] = {
+	eval_access,
+	eval_acl,
+	eval_capable,
+	eval_depth,
+	eval_false,
+	eval_flags,
+	eval_fstype,
+	eval_gid,
+	eval_hidden,
+	eval_inum,
+	eval_links,
+	eval_lname,
+	eval_name,
+	eval_newer,
+	eval_nogroup,
+	eval_nouser,
+	eval_path,
+	eval_perm,
+	eval_regex,
+	eval_samefile,
+	eval_size,
+	eval_sparse,
+	eval_time,
+	eval_true,
+	eval_type,
+	eval_uid,
+	eval_used,
+	eval_xattr,
+	eval_xattrname,
+};
+
 /**
  * Table of simple predicates.
  */
@@ -885,6 +939,7 @@ static const struct {
 } opt_fns[] = {
 	// Primaries
 	{eval_access,   optimize_access},
+	{eval_empty,    optimize_empty},
 	{eval_gid,      optimize_gid},
 	{eval_samefile, optimize_samefile},
 	{eval_type,     optimize_type},
@@ -902,6 +957,13 @@ static const struct {
  * Look up the appropriate optimizer for an expression and call it.
  */
 static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs_expr *expr) {
+	for (size_t i = 0; i < BFS_COUNTOF(opt_pure); ++i) {
+		if (opt_pure[i] == expr->eval_fn) {
+			expr->pure = true;
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
 			infer_pred_facts(state, opt_preds[i].pred);
diff --git a/src/parse.c b/src/parse.c
index 51a9d0a..0b4224c 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -85,6 +85,7 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	expr->argv = argv;
 	expr->persistent_fds = 0;
 	expr->ephemeral_fds = 0;
+	expr->pure = false;
 	expr->cost = FAST_COST;
 	expr->evaluations = 0;
 	expr->successes = 0;
@@ -92,17 +93,14 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	expr->elapsed.tv_nsec = 0;
 
 	if (eval_fn == eval_true) {
-		expr->pure = true;
 		expr->always_true = true;
 		expr->always_false = false;
 		expr->probability = 1.0;
 	} else if (eval_fn == eval_false) {
-		expr->pure = true;
 		expr->always_true = false;
 		expr->always_false = true;
 		expr->probability = 0.0;
 	} else {
-		expr->pure = false;
 		expr->always_true = false;
 		expr->always_false = false;
 		expr->probability = 0.5;
@@ -814,11 +812,7 @@ static struct bfs_expr *parse_unary_option(struct parser_state *state) {
  */
 static struct bfs_expr *parse_test(struct parser_state *state, bfs_eval_fn *eval_fn, size_t argc) {
 	char **argv = parser_advance(state, T_TEST, argc);
-	struct bfs_expr *expr = bfs_expr_new(eval_fn, argc, argv);
-	if (expr) {
-		expr->pure = true;
-	}
-	return expr;
+	return bfs_expr_new(eval_fn, argc, argv);
 }
 
 /**
@@ -1344,16 +1338,7 @@ static struct bfs_expr *parse_empty(struct parser_state *state, int arg1, int ar
 
 	expr->cost = 2000.0;
 	expr->probability = 0.01;
-
-	if (state->ctx->optlevel < 4) {
-		// Since -empty attempts to open and read directories, it may
-		// have side effects such as reporting permission errors, and
-		// thus shouldn't be re-ordered without aggressive optimizations
-		expr->pure = false;
-	}
-
 	expr->ephemeral_fds = 1;
-
 	return expr;
 }
 
@@ -2030,7 +2015,6 @@ static struct bfs_expr *parse_nohidden(struct parser_state *state, int arg1, int
 	}
 
 	hidden->probability = 0.01;
-	hidden->pure = true;
 
 	if (parse_exclude(state, hidden) != 0) {
 		return NULL;
@@ -2766,13 +2750,6 @@ static struct bfs_expr *parse_type(struct parser_state *state, int x, int arg2)
 	expr->num = types;
 	expr->probability = probability;
 
-	if (x && state->ctx->optlevel < 4) {
-		// Since -xtype dereferences symbolic links, it may have side
-		// effects such as reporting permission errors, and thus
-		// shouldn't be re-ordered without aggressive optimizations
-		expr->pure = false;
-	}
-
 	return expr;
 
 fail:
-- 
cgit v1.2.3


From 60b51a3bda3f3fc220a2fa56de5f86c4bac35f2e Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 17:08:58 -0500
Subject: opt: Move always_{true,false} out of the parser

---
 src/opt.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/parse.c | 56 ++++++--------------------------------------------------
 2 files changed, 61 insertions(+), 50 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 934a4b4..c80d584 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -45,6 +45,7 @@
 #include "ctx.h"
 #include "diag.h"
 #include "eval.h"
+#include "exec.h"
 #include "expr.h"
 #include "pwcache.h"
 #include <assert.h>
@@ -799,6 +800,15 @@ static struct bfs_expr *optimize_empty(struct opt_state *state, struct bfs_expr
 	return expr;
 }
 
+/** Optimize -{exec,ok}{,dir}. */
+static struct bfs_expr *optimize_exec(struct opt_state *state, struct bfs_expr *expr) {
+	if (expr->exec->flags & BFS_EXEC_MULTI) {
+		expr->always_true = true;
+	}
+
+	return expr;
+}
+
 /** Optimize -gid. */
 static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
 	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
@@ -891,6 +901,34 @@ static bfs_eval_fn *const opt_pure[] = {
 	eval_xattrname,
 };
 
+/**
+ * Table of always-true expressions.
+ */
+static bfs_eval_fn *const opt_always_true[] = {
+	eval_fls,
+	eval_fprint,
+	eval_fprint0,
+	eval_fprintf,
+	eval_fprintx,
+	eval_prune,
+	eval_true,
+
+	// Non-returning
+	eval_exit,
+	eval_quit,
+};
+
+/**
+ * Table of always-false expressions.
+ */
+static bfs_eval_fn *const opt_always_false[] = {
+	eval_false,
+
+	// Non-returning
+	eval_exit,
+	eval_quit,
+};
+
 /**
  * Table of simple predicates.
  */
@@ -940,6 +978,7 @@ static const struct {
 	// Primaries
 	{eval_access,   optimize_access},
 	{eval_empty,    optimize_empty},
+	{eval_exec,     optimize_exec},
 	{eval_gid,      optimize_gid},
 	{eval_samefile, optimize_samefile},
 	{eval_type,     optimize_type},
@@ -964,6 +1003,20 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 		}
 	}
 
+	for (size_t i = 0; i < BFS_COUNTOF(opt_always_true); ++i) {
+		if (opt_always_true[i] == expr->eval_fn) {
+			expr->always_true = true;
+			break;
+		}
+	}
+
+	for (size_t i = 0; i < BFS_COUNTOF(opt_always_false); ++i) {
+		if (opt_always_false[i] == expr->eval_fn) {
+			expr->always_false = true;
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
 			infer_pred_facts(state, opt_preds[i].pred);
@@ -1026,9 +1079,11 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 	}
 
 	if (expr->always_true) {
+		expr->probability = 1.0;
 		set_facts_impossible(&state->facts_when_false);
 	}
 	if (expr->always_false) {
+		expr->probability = 0.0;
 		set_facts_impossible(&state->facts_when_true);
 	}
 
diff --git a/src/parse.c b/src/parse.c
index 0b4224c..5766237 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -86,26 +86,15 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	expr->persistent_fds = 0;
 	expr->ephemeral_fds = 0;
 	expr->pure = false;
+	expr->always_true = false;
+	expr->always_false = false;
 	expr->cost = FAST_COST;
+	expr->probability = 0.5;
 	expr->evaluations = 0;
 	expr->successes = 0;
 	expr->elapsed.tv_sec = 0;
 	expr->elapsed.tv_nsec = 0;
 
-	if (eval_fn == eval_true) {
-		expr->always_true = true;
-		expr->always_false = false;
-		expr->probability = 1.0;
-	} else if (eval_fn == eval_false) {
-		expr->always_true = false;
-		expr->always_false = true;
-		expr->probability = 0.0;
-	} else {
-		expr->always_true = false;
-		expr->always_false = false;
-		expr->probability = 0.5;
-	}
-
 	// Prevent bfs_expr_free() from freeing uninitialized pointers on error paths
 	if (bfs_expr_is_parent(expr)) {
 		expr->lhs = NULL;
@@ -196,21 +185,6 @@ static struct bfs_expr *new_binary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *l
 	return expr;
 }
 
-/**
- * Set an expression to always return true.
- */
-static void expr_set_always_true(struct bfs_expr *expr) {
-	expr->always_true = true;
-	expr->probability = 1.0;
-}
-
-/**
- * Set an expression to never return.
- */
-static void expr_set_never_returns(struct bfs_expr *expr) {
-	expr->always_true = expr->always_false = true;
-}
-
 /**
  * Color use flags.
  */
@@ -462,7 +436,6 @@ static bool parse_expr_warning(const struct parser_state *state, const struct bf
  * Fill in a "-print"-type expression.
  */
 static void init_print_expr(struct parser_state *state, struct bfs_expr *expr) {
-	expr_set_always_true(expr);
 	expr->cost = PRINT_COST;
 	expr->cfile = state->ctx->cout;
 	expr->path = NULL;
@@ -1359,9 +1332,7 @@ static struct bfs_expr *parse_exec(struct parser_state *state, int flags, int ar
 
 	expr->exec = execbuf;
 
-	if (execbuf->flags & BFS_EXEC_MULTI) {
-		expr_set_always_true(expr);
-	} else {
+	if (!(execbuf->flags & BFS_EXEC_MULTI)) {
 		expr->cost = 1000000.0;
 	}
 
@@ -1395,7 +1366,6 @@ static struct bfs_expr *parse_exit(struct parser_state *state, int arg1, int arg
 
 	struct bfs_expr *expr = parse_action(state, eval_exit, argc);
 	if (expr) {
-		expr_set_never_returns(expr);
 		expr->num = status;
 	}
 	return expr;
@@ -1525,7 +1495,6 @@ static struct bfs_expr *parse_fls(struct parser_state *state, int arg1, int arg2
 		goto fail;
 	}
 
-	expr_set_always_true(expr);
 	expr->cost = PRINT_COST;
 	return expr;
 
@@ -1540,7 +1509,6 @@ fail:
 static struct bfs_expr *parse_fprint(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(state, eval_fprint);
 	if (expr) {
-		expr_set_always_true(expr);
 		expr->cost = PRINT_COST;
 		if (expr_open(state, expr, expr->argv[1]) != 0) {
 			goto fail;
@@ -1559,7 +1527,6 @@ fail:
 static struct bfs_expr *parse_fprint0(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(state, eval_fprint0);
 	if (expr) {
-		expr_set_always_true(expr);
 		expr->cost = PRINT_COST;
 		if (expr_open(state, expr, expr->argv[1]) != 0) {
 			goto fail;
@@ -1595,8 +1562,6 @@ static struct bfs_expr *parse_fprintf(struct parser_state *state, int arg1, int
 		return NULL;
 	}
 
-	expr_set_always_true(expr);
-
 	expr->cost = PRINT_COST;
 
 	if (expr_open(state, expr, file) != 0) {
@@ -2373,23 +2338,14 @@ static struct bfs_expr *parse_printx(struct parser_state *state, int arg1, int a
  */
 static struct bfs_expr *parse_prune(struct parser_state *state, int arg1, int arg2) {
 	state->prune_arg = state->argv;
-
-	struct bfs_expr *expr = parse_nullary_action(state, eval_prune);
-	if (expr) {
-		expr_set_always_true(expr);
-	}
-	return expr;
+	return parse_nullary_action(state, eval_prune);
 }
 
 /**
  * Parse -quit.
  */
 static struct bfs_expr *parse_quit(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_nullary_action(state, eval_quit);
-	if (expr) {
-		expr_set_never_returns(expr);
-	}
-	return expr;
+	return parse_nullary_action(state, eval_quit);
 }
 
 /**
-- 
cgit v1.2.3


From cb3805257092cea2fa6d1fce8d2f99f6b01f44ed Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 17:17:06 -0500
Subject: opt: Move costs out of the parser

---
 src/opt.c   | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/parse.c | 54 +++---------------------------------------------------
 2 files changed, 57 insertions(+), 51 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index c80d584..1daf390 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -804,6 +804,8 @@ static struct bfs_expr *optimize_empty(struct opt_state *state, struct bfs_expr
 static struct bfs_expr *optimize_exec(struct opt_state *state, struct bfs_expr *expr) {
 	if (expr->exec->flags & BFS_EXEC_MULTI) {
 		expr->always_true = true;
+	} else {
+		expr->cost = 1000000.0;
 	}
 
 	return expr;
@@ -929,6 +931,50 @@ static bfs_eval_fn *const opt_always_false[] = {
 	eval_quit,
 };
 
+#define FAST_COST       40.0
+#define FNMATCH_COST   400.0
+#define STAT_COST     1000.0
+#define PRINT_COST   20000.0
+
+/**
+ * Table of expression costs.
+ */
+static const struct {
+	/** The evaluation function with this cost. */
+	bfs_eval_fn *eval_fn;
+	/** The matching cost. */
+	float cost;
+} opt_costs[] = {
+	{eval_access,    STAT_COST},
+	{eval_acl,       STAT_COST},
+	{eval_capable,   STAT_COST},
+	{eval_empty, 2 * STAT_COST}, // readdir() is worse than stat()
+	{eval_fls,      PRINT_COST},
+	{eval_fprint,   PRINT_COST},
+	{eval_fprint0,  PRINT_COST},
+	{eval_fprintf,  PRINT_COST},
+	{eval_fprintx,  PRINT_COST},
+	{eval_fstype,    STAT_COST},
+	{eval_gid,       STAT_COST},
+	{eval_inum,      STAT_COST},
+	{eval_links,     STAT_COST},
+	{eval_lname,  FNMATCH_COST},
+	{eval_name,   FNMATCH_COST},
+	{eval_newer,     STAT_COST},
+	{eval_nogroup,   STAT_COST},
+	{eval_nouser,    STAT_COST},
+	{eval_path,   FNMATCH_COST},
+	{eval_perm,      STAT_COST},
+	{eval_samefile,  STAT_COST},
+	{eval_size,      STAT_COST},
+	{eval_sparse,    STAT_COST},
+	{eval_time,      STAT_COST},
+	{eval_uid,       STAT_COST},
+	{eval_used,      STAT_COST},
+	{eval_xattr,     STAT_COST},
+	{eval_xattrname, STAT_COST},
+};
+
 /**
  * Table of simple predicates.
  */
@@ -1017,6 +1063,14 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 		}
 	}
 
+	expr->cost = FAST_COST;
+	for (size_t i = 0; i < BFS_COUNTOF(opt_costs); ++i) {
+		if (opt_costs[i].eval_fn == expr->eval_fn) {
+			expr->cost = opt_costs[i].cost;
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
 			infer_pred_facts(state, opt_preds[i].pred);
diff --git a/src/parse.c b/src/parse.c
index 5766237..eee185b 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -68,11 +68,6 @@ static char *fake_or_arg = "-o";
 static char *fake_print_arg = "-print";
 static char *fake_true_arg = "-true";
 
-// Cost estimation constants
-#define FAST_COST     40.0
-#define STAT_COST   1000.0
-#define PRINT_COST 20000.0
-
 struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	struct bfs_expr *expr = malloc(sizeof(*expr));
 	if (!expr) {
@@ -88,7 +83,7 @@ struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
 	expr->pure = false;
 	expr->always_true = false;
 	expr->always_false = false;
-	expr->cost = FAST_COST;
+	expr->cost = 0.0;
 	expr->probability = 0.5;
 	expr->evaluations = 0;
 	expr->successes = 0;
@@ -436,7 +431,6 @@ static bool parse_expr_warning(const struct parser_state *state, const struct bf
  * Fill in a "-print"-type expression.
  */
 static void init_print_expr(struct parser_state *state, struct bfs_expr *expr) {
-	expr->cost = PRINT_COST;
 	expr->cfile = state->ctx->cout;
 	expr->path = NULL;
 }
@@ -1021,7 +1015,6 @@ static struct bfs_expr *parse_access(struct parser_state *state, int flag, int a
 	}
 
 	expr->num = flag;
-	expr->cost = STAT_COST;
 
 	switch (flag) {
 	case R_OK:
@@ -1045,7 +1038,6 @@ static struct bfs_expr *parse_acl(struct parser_state *state, int flag, int arg2
 #if BFS_CAN_CHECK_ACL
 	struct bfs_expr *expr = parse_nullary_test(state, eval_acl);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = 0.00002;
 	}
 	return expr;
@@ -1069,7 +1061,6 @@ static struct bfs_expr *parse_newer(struct parser_state *state, int field, int a
 		goto fail;
 	}
 
-	expr->cost = STAT_COST;
 	expr->reftime = sb.mtime;
 	expr->stat_field = field;
 	return expr;
@@ -1088,7 +1079,6 @@ static struct bfs_expr *parse_min(struct parser_state *state, int field, int arg
 		return NULL;
 	}
 
-	expr->cost = STAT_COST;
 	expr->reftime = state->now;
 	expr->stat_field = field;
 	expr->time_unit = BFS_MINUTES;
@@ -1104,7 +1094,6 @@ static struct bfs_expr *parse_time(struct parser_state *state, int field, int ar
 		return NULL;
 	}
 
-	expr->cost = STAT_COST;
 	expr->reftime = state->now;
 	expr->stat_field = field;
 
@@ -1173,7 +1162,6 @@ static struct bfs_expr *parse_capable(struct parser_state *state, int flag, int
 #if BFS_CAN_CHECK_CAPABILITIES
 	struct bfs_expr *expr = parse_nullary_test(state, eval_capable);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = 0.000002;
 	}
 	return expr;
@@ -1309,7 +1297,6 @@ static struct bfs_expr *parse_empty(struct parser_state *state, int arg1, int ar
 		return NULL;
 	}
 
-	expr->cost = 2000.0;
 	expr->probability = 0.01;
 	expr->ephemeral_fds = 1;
 	return expr;
@@ -1332,10 +1319,6 @@ static struct bfs_expr *parse_exec(struct parser_state *state, int flags, int ar
 
 	expr->exec = execbuf;
 
-	if (!(execbuf->flags & BFS_EXEC_MULTI)) {
-		expr->cost = 1000000.0;
-	}
-
 	expr->ephemeral_fds = 2;
 	if (execbuf->flags & BFS_EXEC_CHDIR) {
 		if (execbuf->flags & BFS_EXEC_MULTI) {
@@ -1495,7 +1478,6 @@ static struct bfs_expr *parse_fls(struct parser_state *state, int arg1, int arg2
 		goto fail;
 	}
 
-	expr->cost = PRINT_COST;
 	return expr;
 
 fail:
@@ -1509,7 +1491,6 @@ fail:
 static struct bfs_expr *parse_fprint(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(state, eval_fprint);
 	if (expr) {
-		expr->cost = PRINT_COST;
 		if (expr_open(state, expr, expr->argv[1]) != 0) {
 			goto fail;
 		}
@@ -1527,7 +1508,6 @@ fail:
 static struct bfs_expr *parse_fprint0(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(state, eval_fprint0);
 	if (expr) {
-		expr->cost = PRINT_COST;
 		if (expr_open(state, expr, expr->argv[1]) != 0) {
 			goto fail;
 		}
@@ -1562,8 +1542,6 @@ static struct bfs_expr *parse_fprintf(struct parser_state *state, int arg1, int
 		return NULL;
 	}
 
-	expr->cost = PRINT_COST;
-
 	if (expr_open(state, expr, file) != 0) {
 		goto fail;
 	}
@@ -1594,7 +1572,6 @@ static struct bfs_expr *parse_fstype(struct parser_state *state, int arg1, int a
 		return NULL;
 	}
 
-	expr->cost = STAT_COST;
 	return expr;
 }
 
@@ -1623,7 +1600,6 @@ static struct bfs_expr *parse_group(struct parser_state *state, int arg1, int ar
 		goto fail;
 	}
 
-	expr->cost = STAT_COST;
 	return expr;
 
 fail:
@@ -1643,11 +1619,7 @@ static struct bfs_expr *parse_unique(struct parser_state *state, int arg1, int a
  * Parse -used N.
  */
 static struct bfs_expr *parse_used(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_test_icmp(state, eval_used);
-	if (expr) {
-		expr->cost = STAT_COST;
-	}
-	return expr;
+	return parse_test_icmp(state, eval_used);
 }
 
 /**
@@ -1675,7 +1647,6 @@ static struct bfs_expr *parse_user(struct parser_state *state, int arg1, int arg
 		goto fail;
 	}
 
-	expr->cost = STAT_COST;
 	return expr;
 
 fail:
@@ -1708,7 +1679,6 @@ static struct bfs_expr *parse_ignore_races(struct parser_state *state, int ignor
 static struct bfs_expr *parse_inum(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_test_icmp(state, eval_inum);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = expr->int_cmp == BFS_INT_EQUAL ? 0.01 : 0.50;
 	}
 	return expr;
@@ -1720,7 +1690,6 @@ static struct bfs_expr *parse_inum(struct parser_state *state, int arg1, int arg
 static struct bfs_expr *parse_links(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_test_icmp(state, eval_links);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = bfs_expr_cmp(expr, 1) ? 0.99 : 0.01;
 	}
 	return expr;
@@ -1795,8 +1764,6 @@ static struct bfs_expr *parse_fnmatch(const struct parser_state *state, struct b
 		return expr;
 	}
 
-	expr->cost = 400.0;
-
 	if (strchr(pattern, '*')) {
 		expr->probability = 0.5;
 	} else {
@@ -1942,8 +1909,6 @@ static struct bfs_expr *parse_newerxy(struct parser_state *state, int arg1, int
 		expr->reftime = *reftime;
 	}
 
-	expr->cost = STAT_COST;
-
 	return expr;
 
 fail:
@@ -1960,7 +1925,6 @@ static struct bfs_expr *parse_nogroup(struct parser_state *state, int arg1, int
 		return NULL;
 	}
 
-	expr->cost = STAT_COST;
 	expr->probability = 0.01;
 
 	// Who knows how many FDs getgrgid_r() needs?  Probably at least one for
@@ -2006,7 +1970,6 @@ static struct bfs_expr *parse_nouser(struct parser_state *state, int arg1, int a
 		return NULL;
 	}
 
-	expr->cost = STAT_COST;
 	expr->probability = 0.01;
 
 	// Who knows how many FDs getpwuid_r() needs?  Probably at least one for
@@ -2272,8 +2235,6 @@ static struct bfs_expr *parse_perm(struct parser_state *state, int field, int ar
 		goto fail;
 	}
 
-	expr->cost = STAT_COST;
-
 	return expr;
 
 fail:
@@ -2468,7 +2429,6 @@ static struct bfs_expr *parse_samefile(struct parser_state *state, int arg1, int
 	expr->dev = sb.dev;
 	expr->ino = sb.ino;
 
-	expr->cost = STAT_COST;
 	expr->probability = 0.01;
 
 	return expr;
@@ -2531,7 +2491,6 @@ static struct bfs_expr *parse_since(struct parser_state *state, int field, int a
 		goto fail;
 	}
 
-	expr->cost = STAT_COST;
 	expr->stat_field = field;
 	return expr;
 
@@ -2589,7 +2548,6 @@ static struct bfs_expr *parse_size(struct parser_state *state, int arg1, int arg
 		goto bad_unit;
 	}
 
-	expr->cost = STAT_COST;
 	expr->probability = expr->int_cmp == BFS_INT_EQUAL ? 0.01 : 0.50;
 
 	return expr;
@@ -2605,11 +2563,7 @@ fail:
  * Parse -sparse.
  */
 static struct bfs_expr *parse_sparse(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_nullary_test(state, eval_sparse);
-	if (expr) {
-		expr->cost = STAT_COST;
-	}
-	return expr;
+	return parse_nullary_test(state, eval_sparse);
 }
 
 /**
@@ -2728,7 +2682,6 @@ static struct bfs_expr *parse_xattr(struct parser_state *state, int arg1, int ar
 #if BFS_CAN_CHECK_XATTRS
 	struct bfs_expr *expr = parse_nullary_test(state, eval_xattr);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = 0.01;
 	}
 	return expr;
@@ -2745,7 +2698,6 @@ static struct bfs_expr *parse_xattrname(struct parser_state *state, int arg1, in
 #if BFS_CAN_CHECK_XATTRS
 	struct bfs_expr *expr = parse_unary_test(state, eval_xattrname);
 	if (expr) {
-		expr->cost = STAT_COST;
 		expr->probability = 0.01;
 	}
 	return expr;
-- 
cgit v1.2.3


From 220fb782da63fd648dedb02a7c43c837792b3d4a Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Tue, 24 Jan 2023 17:23:18 -0500
Subject: opt: Move probabilities out of the parser

---
 src/opt.c   | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/parse.c | 149 ++++++++++++------------------------------------------------
 2 files changed, 161 insertions(+), 120 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 1daf390..e76e216 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -54,6 +54,7 @@
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 
 static char *fake_and_arg = "-a";
@@ -776,15 +777,23 @@ static void infer_icmp_facts(struct opt_state *state, const struct bfs_expr *exp
 
 /** Optimize -{execut,read,writ}able. */
 static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr *expr) {
+	expr->probability = 1.0;
+
 	if (expr->num & R_OK) {
 		infer_pred_facts(state, READABLE_PRED);
+		expr->probability *= 0.99;
 	}
+
 	if (expr->num & W_OK) {
 		infer_pred_facts(state, WRITABLE_PRED);
+		expr->probability *= 0.8;
 	}
+
 	if (expr->num & X_OK) {
 		infer_pred_facts(state, EXECUTABLE_PRED);
+		expr->probability *= 0.2;
 	}
+
 	return expr;
 }
 
@@ -811,6 +820,17 @@ static struct bfs_expr *optimize_exec(struct opt_state *state, struct bfs_expr *
 	return expr;
 }
 
+/** Optimize -name/-lname/-path. */
+static struct bfs_expr *optimize_fnmatch(struct opt_state *state, struct bfs_expr *expr) {
+	if (strchr(expr->argv[1], '*')) {
+		expr->probability = 0.5;
+	} else {
+		expr->probability = 0.1;
+	}
+
+	return expr;
+}
+
 /** Optimize -gid. */
 static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
 	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
@@ -825,6 +845,30 @@ static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *e
 	return expr;
 }
 
+/** Optimize -inum. */
+static struct bfs_expr *optimize_inum(struct opt_state *state, struct bfs_expr *expr) {
+	struct range *range = &state->facts_when_true.ranges[INUM_RANGE];
+	if (range->min == range->max) {
+		expr->probability = 0.01;
+	} else {
+		expr->probability = 0.5;
+	}
+
+	return expr;
+}
+
+/** Optimize -links. */
+static struct bfs_expr *optimize_links(struct opt_state *state, struct bfs_expr *expr) {
+	struct range *range = &state->facts_when_true.ranges[LINKS_RANGE];
+	if (1 >= range->min && 1 <= range->max) {
+		expr->probability = 0.99;
+	} else {
+		expr->probability = 0.5;
+	}
+
+	return expr;
+}
+
 /** Optimize -uid. */
 static struct bfs_expr *optimize_uid(struct opt_state *state, struct bfs_expr *expr) {
 	struct range *range = &state->facts_when_true.ranges[UID_RANGE];
@@ -847,10 +891,59 @@ static struct bfs_expr *optimize_samefile(struct opt_state *state, struct bfs_ex
 	return expr;
 }
 
+/** Optimize -size. */
+static struct bfs_expr *optimize_size(struct opt_state *state, struct bfs_expr *expr) {
+	struct range *range = &state->facts_when_true.ranges[SIZE_RANGE];
+	if (range->min == range->max) {
+		expr->probability = 0.01;
+	} else {
+		expr->probability = 0.5;
+	}
+
+	return expr;
+}
+
+/** Estimate probability for -x?type. */
+static void estimate_type_probability(struct bfs_expr *expr) {
+	unsigned int types = expr->num;
+
+	expr->probability = 0.0;
+	if (types & (1 << BFS_BLK)) {
+		expr->probability += 0.00000721183;
+	}
+	if (types & (1 << BFS_CHR)) {
+		expr->probability += 0.0000499855;
+	}
+	if (types & (1 << BFS_DIR)) {
+		expr->probability += 0.114475;
+	}
+	if (types & (1 << BFS_DOOR)) {
+		expr->probability += 0.000001;
+	}
+	if (types & (1 << BFS_FIFO)) {
+		expr->probability += 0.00000248684;
+	}
+	if (types & (1 << BFS_REG)) {
+		expr->probability += 0.859772;
+	}
+	if (types & (1 << BFS_LNK)) {
+		expr->probability += 0.0256816;
+	}
+	if (types & (1 << BFS_SOCK)) {
+		expr->probability += 0.0000116881;
+	}
+	if (types & (1 << BFS_WHT)) {
+		expr->probability += 0.000001;
+	}
+}
+
 /** Optimize -type. */
 static struct bfs_expr *optimize_type(struct opt_state *state, struct bfs_expr *expr) {
 	state->facts_when_true.types &= expr->num;
 	state->facts_when_false.types &= ~expr->num;
+
+	estimate_type_probability(expr);
+
 	return expr;
 }
 
@@ -865,6 +958,9 @@ static struct bfs_expr *optimize_xtype(struct opt_state *state, struct bfs_expr
 
 	state->facts_when_true.xtypes &= expr->num;
 	state->facts_when_false.xtypes &= ~expr->num;
+
+	estimate_type_probability(expr);
+
 	return expr;
 }
 
@@ -975,6 +1071,29 @@ static const struct {
 	{eval_xattrname, STAT_COST},
 };
 
+/**
+ * Table of expression probabilities.
+ */
+static const struct {
+	/** The evaluation function with this cost. */
+	bfs_eval_fn *eval_fn;
+	/** The matching probability. */
+	float probability;
+} opt_probs[] = {
+	{eval_acl,       0.00002},
+	{eval_capable,   0.000002},
+	{eval_empty,     0.01},
+	{eval_false,     0.0},
+	{eval_hidden,    0.01},
+	{eval_nogroup,   0.01},
+	{eval_nouser,    0.01},
+	{eval_samefile,  0.01},
+	{eval_true,      1.0},
+	{eval_xattr,     0.01},
+	{eval_xattrname, 0.01},
+};
+
+
 /**
  * Table of simple predicates.
  */
@@ -1026,7 +1145,13 @@ static const struct {
 	{eval_empty,    optimize_empty},
 	{eval_exec,     optimize_exec},
 	{eval_gid,      optimize_gid},
+	{eval_inum,     optimize_inum},
+	{eval_links,    optimize_links},
+	{eval_lname,    optimize_fnmatch},
+	{eval_name,     optimize_fnmatch},
+	{eval_path,     optimize_fnmatch},
 	{eval_samefile, optimize_samefile},
+	{eval_size,     optimize_size},
 	{eval_type,     optimize_type},
 	{eval_uid,      optimize_uid},
 	{eval_xtype,    optimize_xtype},
@@ -1071,6 +1196,13 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 		}
 	}
 
+	for (size_t i = 0; i < BFS_COUNTOF(opt_probs); ++i) {
+		if (opt_probs[i].eval_fn == expr->eval_fn) {
+			expr->probability = opt_probs[i].probability;
+			break;
+		}
+	}
+
 	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
 			infer_pred_facts(state, opt_preds[i].pred);
diff --git a/src/parse.c b/src/parse.c
index eee185b..f2582e0 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -1010,24 +1010,9 @@ static struct bfs_expr *parse_xargs_safe(struct parser_state *state, int arg1, i
  */
 static struct bfs_expr *parse_access(struct parser_state *state, int flag, int arg2) {
 	struct bfs_expr *expr = parse_nullary_test(state, eval_access);
-	if (!expr) {
-		return NULL;
-	}
-
-	expr->num = flag;
-
-	switch (flag) {
-	case R_OK:
-		expr->probability = 0.99;
-		break;
-	case W_OK:
-		expr->probability = 0.8;
-		break;
-	case X_OK:
-		expr->probability = 0.2;
-		break;
+	if (expr) {
+		expr->num = flag;
 	}
-
 	return expr;
 }
 
@@ -1036,11 +1021,7 @@ static struct bfs_expr *parse_access(struct parser_state *state, int flag, int a
  */
 static struct bfs_expr *parse_acl(struct parser_state *state, int flag, int arg2) {
 #if BFS_CAN_CHECK_ACL
-	struct bfs_expr *expr = parse_nullary_test(state, eval_acl);
-	if (expr) {
-		expr->probability = 0.00002;
-	}
-	return expr;
+	return parse_nullary_test(state, eval_acl);
 #else
 	parse_error(state, "Missing platform support.\n");
 	return NULL;
@@ -1160,11 +1141,7 @@ fail:
  */
 static struct bfs_expr *parse_capable(struct parser_state *state, int flag, int arg2) {
 #if BFS_CAN_CHECK_CAPABILITIES
-	struct bfs_expr *expr = parse_nullary_test(state, eval_capable);
-	if (expr) {
-		expr->probability = 0.000002;
-	}
-	return expr;
+	return parse_nullary_test(state, eval_capable);
 #else
 	parse_error(state, "Missing platform support.\n");
 	return NULL;
@@ -1293,12 +1270,9 @@ static struct bfs_expr *parse_depth_limit(struct parser_state *state, int is_min
  */
 static struct bfs_expr *parse_empty(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_nullary_test(state, eval_empty);
-	if (!expr) {
-		return NULL;
+	if (expr) {
+		expr->ephemeral_fds = 1;
 	}
-
-	expr->probability = 0.01;
-	expr->ephemeral_fds = 1;
 	return expr;
 }
 
@@ -1658,11 +1632,7 @@ fail:
  * Parse -hidden.
  */
 static struct bfs_expr *parse_hidden(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_nullary_test(state, eval_hidden);
-	if (expr) {
-		expr->probability = 0.01;
-	}
-	return expr;
+	return parse_nullary_test(state, eval_hidden);
 }
 
 /**
@@ -1677,22 +1647,14 @@ static struct bfs_expr *parse_ignore_races(struct parser_state *state, int ignor
  * Parse -inum N.
  */
 static struct bfs_expr *parse_inum(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_test_icmp(state, eval_inum);
-	if (expr) {
-		expr->probability = expr->int_cmp == BFS_INT_EQUAL ? 0.01 : 0.50;
-	}
-	return expr;
+	return parse_test_icmp(state, eval_inum);
 }
 
 /**
  * Parse -links N.
  */
 static struct bfs_expr *parse_links(struct parser_state *state, int arg1, int arg2) {
-	struct bfs_expr *expr = parse_test_icmp(state, eval_links);
-	if (expr) {
-		expr->probability = bfs_expr_cmp(expr, 1) ? 0.99 : 0.01;
-	}
-	return expr;
+	return parse_test_icmp(state, eval_links);
 }
 
 /**
@@ -1764,12 +1726,6 @@ static struct bfs_expr *parse_fnmatch(const struct parser_state *state, struct b
 		return expr;
 	}
 
-	if (strchr(pattern, '*')) {
-		expr->probability = 0.5;
-	} else {
-		expr->probability = 0.1;
-	}
-
 	return expr;
 }
 
@@ -1921,16 +1877,11 @@ fail:
  */
 static struct bfs_expr *parse_nogroup(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_nullary_test(state, eval_nogroup);
-	if (!expr) {
-		return NULL;
+	if (expr) {
+		// Who knows how many FDs getgrgid_r() needs?  Probably at least
+		// one for /etc/group
+		expr->ephemeral_fds = 1;
 	}
-
-	expr->probability = 0.01;
-
-	// Who knows how many FDs getgrgid_r() needs?  Probably at least one for
-	// /etc/group
-	expr->ephemeral_fds = 1;
-
 	return expr;
 }
 
@@ -1943,8 +1894,6 @@ static struct bfs_expr *parse_nohidden(struct parser_state *state, int arg1, int
 		return NULL;
 	}
 
-	hidden->probability = 0.01;
-
 	if (parse_exclude(state, hidden) != 0) {
 		return NULL;
 	}
@@ -1966,16 +1915,11 @@ static struct bfs_expr *parse_noleaf(struct parser_state *state, int arg1, int a
  */
 static struct bfs_expr *parse_nouser(struct parser_state *state, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_nullary_test(state, eval_nouser);
-	if (!expr) {
-		return NULL;
+	if (expr) {
+		// Who knows how many FDs getpwuid_r() needs?  Probably at least
+		// one for /etc/passwd
+		expr->ephemeral_fds = 1;
 	}
-
-	expr->probability = 0.01;
-
-	// Who knows how many FDs getpwuid_r() needs?  Probably at least one for
-	// /etc/passwd
-	expr->ephemeral_fds = 1;
-
 	return expr;
 }
 
@@ -2428,9 +2372,6 @@ static struct bfs_expr *parse_samefile(struct parser_state *state, int arg1, int
 
 	expr->dev = sb.dev;
 	expr->ino = sb.ino;
-
-	expr->probability = 0.01;
-
 	return expr;
 }
 
@@ -2548,8 +2489,6 @@ static struct bfs_expr *parse_size(struct parser_state *state, int arg1, int arg
 		goto bad_unit;
 	}
 
-	expr->probability = expr->int_cmp == BFS_INT_EQUAL ? 0.01 : 0.50;
-
 	return expr;
 
 bad_unit:
@@ -2584,50 +2523,37 @@ static struct bfs_expr *parse_type(struct parser_state *state, int x, int arg2)
 		return NULL;
 	}
 
-	unsigned int types = 0;
-	float probability = 0.0;
+	expr->num = 0;
 
 	const char *c = expr->argv[1];
 	while (true) {
-		enum bfs_type type;
-		float type_prob;
-
 		switch (*c) {
 		case 'b':
-			type = BFS_BLK;
-			type_prob = 0.00000721183;
+			expr->num |= 1 << BFS_BLK;
 			break;
 		case 'c':
-			type = BFS_CHR;
-			type_prob = 0.0000499855;
+			expr->num |= 1 << BFS_CHR;
 			break;
 		case 'd':
-			type = BFS_DIR;
-			type_prob = 0.114475;
+			expr->num |= 1 << BFS_DIR;
 			break;
 		case 'D':
-			type = BFS_DOOR;
-			type_prob = 0.000001;
+			expr->num |= 1 << BFS_DOOR;
 			break;
 		case 'p':
-			type = BFS_FIFO;
-			type_prob = 0.00000248684;
+			expr->num |= 1 << BFS_FIFO;
 			break;
 		case 'f':
-			type = BFS_REG;
-			type_prob = 0.859772;
+			expr->num |= 1 << BFS_REG;
 			break;
 		case 'l':
-			type = BFS_LNK;
-			type_prob = 0.0256816;
+			expr->num |= 1 << BFS_LNK;
 			break;
 		case 's':
-			type = BFS_SOCK;
-			type_prob = 0.0000116881;
+			expr->num |= 1 << BFS_SOCK;
 			break;
 		case 'w':
-			type = BFS_WHT;
-			type_prob = 0.000001;
+			expr->num |= 1 << BFS_WHT;
 			break;
 
 		case '\0':
@@ -2639,12 +2565,6 @@ static struct bfs_expr *parse_type(struct parser_state *state, int x, int arg2)
 			goto fail;
 		}
 
-		unsigned int flag = 1 << type;
-		if (!(types & flag)) {
-			types |= flag;
-			probability += type_prob;
-		}
-
 		++c;
 		if (*c == '\0') {
 			break;
@@ -2657,9 +2577,6 @@ static struct bfs_expr *parse_type(struct parser_state *state, int x, int arg2)
 		}
 	}
 
-	expr->num = types;
-	expr->probability = probability;
-
 	return expr;
 
 fail:
@@ -2680,11 +2597,7 @@ static struct bfs_expr *parse_warn(struct parser_state *state, int warn, int arg
  */
 static struct bfs_expr *parse_xattr(struct parser_state *state, int arg1, int arg2) {
 #if BFS_CAN_CHECK_XATTRS
-	struct bfs_expr *expr = parse_nullary_test(state, eval_xattr);
-	if (expr) {
-		expr->probability = 0.01;
-	}
-	return expr;
+	return parse_nullary_test(state, eval_xattr);
 #else
 	parse_error(state, "Missing platform support.\n");
 	return NULL;
@@ -2696,11 +2609,7 @@ static struct bfs_expr *parse_xattr(struct parser_state *state, int arg1, int ar
  */
 static struct bfs_expr *parse_xattrname(struct parser_state *state, int arg1, int arg2) {
 #if BFS_CAN_CHECK_XATTRS
-	struct bfs_expr *expr = parse_unary_test(state, eval_xattrname);
-	if (expr) {
-		expr->probability = 0.01;
-	}
-	return expr;
+	return parse_unary_test(state, eval_xattrname);
 #else
 	parse_error(state, "Missing platform support.\n");
 	return NULL;
-- 
cgit v1.2.3


From 9463fdd30d392c98de7b5712d30dfbaeada40e99 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 25 Jan 2023 16:14:11 -0500
Subject: Replace license boilerplate with SPDX tags

And while I'm at it, remove years from copyright declarations.

Link: https://spdx.dev/about/
Link: https://daniel.haxx.se/blog/2023/01/08/copyright-without-years/
---
 LICENSE              | 33 +++++++++++++++++++++------------
 Makefile             | 17 ++---------------
 completions/bfs.bash | 21 ++++-----------------
 src/bar.c            | 17 ++---------------
 src/bar.h            | 17 ++---------------
 src/bfstd.c          | 17 ++---------------
 src/bfstd.h          | 17 ++---------------
 src/bftw.c           | 17 ++---------------
 src/bftw.h           | 17 ++---------------
 src/color.c          | 17 ++---------------
 src/color.h          | 17 ++---------------
 src/config.h         | 17 ++---------------
 src/ctx.c            | 17 ++---------------
 src/ctx.h            | 17 ++---------------
 src/darray.c         | 17 ++---------------
 src/darray.h         | 17 ++---------------
 src/diag.c           | 17 ++---------------
 src/diag.h           | 17 ++---------------
 src/dir.c            | 17 ++---------------
 src/dir.h            | 17 ++---------------
 src/dstring.c        | 17 ++---------------
 src/dstring.h        | 17 ++---------------
 src/eval.c           | 17 ++---------------
 src/eval.h           | 17 ++---------------
 src/exec.c           | 17 ++---------------
 src/exec.h           | 17 ++---------------
 src/expr.h           | 17 ++---------------
 src/fsade.c          | 17 ++---------------
 src/fsade.h          | 17 ++---------------
 src/main.c           | 17 ++---------------
 src/mtab.c           | 17 ++---------------
 src/mtab.h           | 17 ++---------------
 src/opt.c            | 17 ++---------------
 src/opt.h            | 17 ++---------------
 src/parse.c          | 17 ++---------------
 src/parse.h          | 17 ++---------------
 src/printf.c         | 17 ++---------------
 src/printf.h         | 17 ++---------------
 src/pwcache.c        | 17 ++---------------
 src/pwcache.h        | 17 ++---------------
 src/stat.c           | 17 ++---------------
 src/stat.h           | 17 ++---------------
 src/trie.c           | 17 ++---------------
 src/trie.h           | 17 ++---------------
 src/typo.c           | 17 ++---------------
 src/typo.h           | 17 ++---------------
 src/xregex.c         | 17 ++---------------
 src/xregex.h         | 18 ++----------------
 src/xspawn.c         | 17 ++---------------
 src/xspawn.h         | 17 ++---------------
 src/xtime.c          | 17 ++---------------
 src/xtime.h          | 17 ++---------------
 tests/bfstd.c        | 17 ++---------------
 tests/find-color.sh  | 17 ++---------------
 tests/ls-color.sh    | 17 ++---------------
 tests/mksock.c       | 17 ++---------------
 tests/tests.sh       | 17 ++---------------
 tests/trie.c         | 17 ++---------------
 tests/xtimegm.c      | 17 ++---------------
 tests/xtouch.c       | 17 ++---------------
 60 files changed, 141 insertions(+), 900 deletions(-)

(limited to 'src/opt.c')

diff --git a/LICENSE b/LICENSE
index 069b145..290e3d3 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,12 +1,21 @@
-Copyright (C) 2015-2021 Tavian Barnes <tavianator@tavianator.com>
-
-Permission to use, copy, modify, and/or distribute this software for any
-purpose with or without fee is hereby granted.
-
-THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+Copyright © 2015-2023 Tavian Barnes <tavianator@tavianator.com> and the bfs contributors
+
+Permission to use, copy, modify, and/or distribute this software for any purpose with or
+without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT
+SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR
+ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
+
+---
+
+bfs is licensed under the Zero Clause BSD License.  Individual files contain the following
+tag instead of the full license text:
+
+    SPDX-License-Identifier: 0BSD
+
+This enables machine processing of license information based on the SPDX License
+Identifiers that are available here: https://spdx.org/licenses/
diff --git a/Makefile b/Makefile
index b39a88a..0247b47 100644
--- a/Makefile
+++ b/Makefile
@@ -1,18 +1,5 @@
-############################################################################
-# bfs                                                                      #
-# Copyright (C) 2015-2023 Tavian Barnes <tavianator@tavianator.com>        #
-#                                                                          #
-# Permission to use, copy, modify, and/or distribute this software for any #
-# purpose with or without fee is hereby granted.                           #
-#                                                                          #
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES #
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         #
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  #
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   #
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    #
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  #
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           #
-############################################################################
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
 
 ifneq ($(wildcard .git),)
 VERSION := $(shell git describe --always 2>/dev/null)
diff --git a/completions/bfs.bash b/completions/bfs.bash
index f734ab1..2f52e8d 100644
--- a/completions/bfs.bash
+++ b/completions/bfs.bash
@@ -1,21 +1,8 @@
-# bash completion script for bfs
+# Copyright © Benjamin Mundt <benMundt@ibm.com>
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
 
-############################################################################
-# bfs                                                                      #
-# Copyright (C) 2020 Benjamin Mundt <benMundt@ibm.com>                     #
-# Copyright (C) 2021 Tavian Barnes <tavianator@tavianator.com>             #
-#                                                                          #
-# Permission to use, copy, modify, and/or distribute this software for any #
-# purpose with or without fee is hereby granted.                           #
-#                                                                          #
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES #
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         #
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  #
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   #
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    #
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  #
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           #
-############################################################################
+# bash completion script for bfs
 
 _bfs() {
     local cur prev words cword
diff --git a/src/bar.c b/src/bar.c
index 37d33c8..bd5d381 100644
--- a/src/bar.c
+++ b/src/bar.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "bar.h"
 #include "bfstd.h"
diff --git a/src/bar.h b/src/bar.h
index 3e509d6..20d92a9 100644
--- a/src/bar.h
+++ b/src/bar.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A terminal status bar.
diff --git a/src/bfstd.c b/src/bfstd.c
index 3a37250..437e9c9 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "bfstd.h"
 #include "config.h"
diff --git a/src/bfstd.h b/src/bfstd.h
index 79307cc..0e11b66 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Standard library wrappers and polyfills.
diff --git a/src/bftw.c b/src/bftw.c
index 5f3ebde..9feca79 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * The bftw() implementation consists of the following components:
diff --git a/src/bftw.h b/src/bftw.h
index c458e1b..77697ed 100644
--- a/src/bftw.h
+++ b/src/bftw.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2021 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A file-walking API based on nftw().
diff --git a/src/color.c b/src/color.c
index 7c16ec5..589e631 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "color.h"
 #include "bfstd.h"
diff --git a/src/color.h b/src/color.h
index 5b350cc..737c34b 100644
--- a/src/color.h
+++ b/src/color.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2021 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Utilities for colored output on ANSI terminals.
diff --git a/src/config.h b/src/config.h
index 810f913..5ae9c82 100644
--- a/src/config.h
+++ b/src/config.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Configuration and feature/platform detection.
diff --git a/src/ctx.c b/src/ctx.c
index 0403299..ff4a2a7 100644
--- a/src/ctx.c
+++ b/src/ctx.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "ctx.h"
 #include "color.h"
diff --git a/src/ctx.h b/src/ctx.h
index 6755d02..4c748b7 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * bfs execution context.
diff --git a/src/darray.c b/src/darray.c
index 6585d30..42b8397 100644
--- a/src/darray.c
+++ b/src/darray.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "darray.h"
 #include <stdlib.h>
diff --git a/src/darray.h b/src/darray.h
index 4464381..cc6cc42 100644
--- a/src/darray.h
+++ b/src/darray.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A dynamic array library.
diff --git a/src/diag.c b/src/diag.c
index b02473a..53db98e 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "diag.h"
 #include "bfstd.h"
diff --git a/src/diag.h b/src/diag.h
index 8d0b19f..2952e30 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Formatters for diagnostic messages.
diff --git a/src/dir.c b/src/dir.c
index 2081cc5..3d18eb2 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2021-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "dir.h"
 #include "bfstd.h"
diff --git a/src/dir.h b/src/dir.h
index 69344c6..01eaaba 100644
--- a/src/dir.h
+++ b/src/dir.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2021 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Directories and their contents.
diff --git a/src/dstring.c b/src/dstring.c
index f344d09..9112e54 100644
--- a/src/dstring.c
+++ b/src/dstring.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "dstring.h"
 #include <assert.h>
diff --git a/src/dstring.h b/src/dstring.h
index df20a04..ee3b345 100644
--- a/src/dstring.h
+++ b/src/dstring.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016-2020 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A dynamic string library.
diff --git a/src/eval.c b/src/eval.c
index d297af1..53ce605 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Implementation of all the primary expressions.
diff --git a/src/eval.h b/src/eval.h
index a50dc4e..3d70319 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * The evaluation functions that implement primary expressions like -name,
diff --git a/src/exec.c b/src/exec.c
index 8630469..6bde1c1 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "exec.h"
 #include "bfstd.h"
diff --git a/src/exec.h b/src/exec.h
index a3e3c71..9d4192d 100644
--- a/src/exec.h
+++ b/src/exec.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2020 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Implementation of -exec/-execdir/-ok/-okdir.
diff --git a/src/expr.h b/src/expr.h
index a52007a..1628cac 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * The expression tree representation.
diff --git a/src/fsade.c b/src/fsade.c
index 45969d1..a61a6b8 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2021 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "fsade.h"
 #include "config.h"
diff --git a/src/fsade.h b/src/fsade.h
index f45c6fd..9bef892 100644
--- a/src/fsade.h
+++ b/src/fsade.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2020 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A facade over (file)system features that are (un)implemented differently
diff --git a/src/main.c b/src/main.c
index fbddbe5..4f99580 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * - main(): the entry point for bfs(1), a breadth-first version of find(1)
diff --git a/src/mtab.c b/src/mtab.c
index 07d7a53..ae6dfd2 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2020 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "mtab.h"
 #include "bfstd.h"
diff --git a/src/mtab.h b/src/mtab.h
index 807539d..5dfdf6c 100644
--- a/src/mtab.h
+++ b/src/mtab.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2020 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A facade over platform-specific APIs for enumerating mounted filesystems.
diff --git a/src/opt.c b/src/opt.c
index e76e216..5505b7b 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * The expression optimizer.  Different optimization levels are supported:
diff --git a/src/opt.h b/src/opt.h
index 5f8180d..28cadb9 100644
--- a/src/opt.h
+++ b/src/opt.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Optimization.
diff --git a/src/parse.c b/src/parse.c
index f2582e0..30bf56d 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * The command line parser.  Expressions are parsed by recursive descent, with a
diff --git a/src/parse.h b/src/parse.h
index 7e29a03..6895c9f 100644
--- a/src/parse.h
+++ b/src/parse.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * bfs command line parsing.
diff --git a/src/printf.c b/src/printf.c
index 7c0c8db..1b4f2d4 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "printf.h"
 #include "bfstd.h"
diff --git a/src/printf.h b/src/printf.h
index a8c5f2a..2bff087 100644
--- a/src/printf.h
+++ b/src/printf.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2017-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Implementation of -printf/-fprintf.
diff --git a/src/pwcache.c b/src/pwcache.c
index 868ec8f..5026dee 100644
--- a/src/pwcache.c
+++ b/src/pwcache.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "pwcache.h"
 #include "darray.h"
diff --git a/src/pwcache.h b/src/pwcache.h
index f1ca0bf..b6c0b67 100644
--- a/src/pwcache.h
+++ b/src/pwcache.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A caching wrapper for /etc/{passwd,group}.
diff --git a/src/stat.c b/src/stat.c
index 94dedef..aaa5eac 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2018-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "stat.h"
 #include "bfstd.h"
diff --git a/src/stat.h b/src/stat.h
index 44cbfad..7a70146 100644
--- a/src/stat.h
+++ b/src/stat.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2018-2019 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A facade over the stat() API that unifies some details that diverge between
diff --git a/src/trie.c b/src/trie.c
index 08a99b5..77c43cc 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * This is an implementation of a "qp trie," as documented at
diff --git a/src/trie.h b/src/trie.h
index 2ede6ea..03ee64d 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #ifndef BFS_TRIE_H
 #define BFS_TRIE_H
diff --git a/src/typo.c b/src/typo.c
index c16cab4..305711d 100644
--- a/src/typo.c
+++ b/src/typo.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "typo.h"
 #include <limits.h>
diff --git a/src/typo.h b/src/typo.h
index 0347aae..13eaa67 100644
--- a/src/typo.h
+++ b/src/typo.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2016 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #ifndef BFS_TYPO_H
 #define BFS_TYPO_H
diff --git a/src/xregex.c b/src/xregex.c
index 6f0e5a1..5f5480f 100644
--- a/src/xregex.c
+++ b/src/xregex.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2022 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "xregex.h"
 #include "config.h"
diff --git a/src/xregex.h b/src/xregex.h
index b2f56a5..998a2b0 100644
--- a/src/xregex.h
+++ b/src/xregex.h
@@ -1,19 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2022 Tavian Barnes <tavianator@tavianator.com> and bfs     *
- * contributors                                                             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com> and the bfs contributors
+// SPDX-License-Identifier: 0BSD
 
 #ifndef BFS_XREGEX_H
 #define BFS_XREGEX_H
diff --git a/src/xspawn.c b/src/xspawn.c
index f76267b..a30c264 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2018-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "xspawn.h"
 #include "bfstd.h"
diff --git a/src/xspawn.h b/src/xspawn.h
index cd6a42e..3dbf5d2 100644
--- a/src/xspawn.h
+++ b/src/xspawn.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2018-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * A process-spawning library inspired by posix_spawn().
diff --git a/src/xtime.c b/src/xtime.c
index 079d42a..82690d0 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "xtime.h"
 #include <errno.h>
diff --git a/src/xtime.h b/src/xtime.h
index b49cd04..75d1f4e 100644
--- a/src/xtime.h
+++ b/src/xtime.h
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * Date/time handling.
diff --git a/tests/bfstd.c b/tests/bfstd.c
index 4a8181b..8c61072 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2022 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "../src/bfstd.h"
 #include <stdio.h>
diff --git a/tests/find-color.sh b/tests/find-color.sh
index ecdd5af..47de2a2 100755
--- a/tests/find-color.sh
+++ b/tests/find-color.sh
@@ -1,20 +1,7 @@
 #!/usr/bin/env bash
 
-############################################################################
-# bfs                                                                      #
-# Copyright (C) 2019 Tavian Barnes <tavianator@tavianator.com>             #
-#                                                                          #
-# Permission to use, copy, modify, and/or distribute this software for any #
-# purpose with or without fee is hereby granted.                           #
-#                                                                          #
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES #
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         #
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  #
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   #
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    #
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  #
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           #
-############################################################################
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
 
 set -e
 
diff --git a/tests/ls-color.sh b/tests/ls-color.sh
index c82a58d..6d33f53 100755
--- a/tests/ls-color.sh
+++ b/tests/ls-color.sh
@@ -1,20 +1,7 @@
 #!/usr/bin/env bash
 
-############################################################################
-# bfs                                                                      #
-# Copyright (C) 2019 Tavian Barnes <tavianator@tavianator.com>             #
-#                                                                          #
-# Permission to use, copy, modify, and/or distribute this software for any #
-# purpose with or without fee is hereby granted.                           #
-#                                                                          #
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES #
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         #
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  #
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   #
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    #
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  #
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           #
-############################################################################
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
 
 # Prints the "ground truth" coloring of a path using ls
 
diff --git a/tests/mksock.c b/tests/mksock.c
index 5068bc8..05edbeb 100644
--- a/tests/mksock.c
+++ b/tests/mksock.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2019 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 /**
  * There's no standard Unix utility that creates a socket file, so this small
diff --git a/tests/tests.sh b/tests/tests.sh
index e57db4e..98d332c 100755
--- a/tests/tests.sh
+++ b/tests/tests.sh
@@ -1,20 +1,7 @@
 #!/usr/bin/env bash
 
-############################################################################
-# bfs                                                                      #
-# Copyright (C) 2015-2022 Tavian Barnes <tavianator@tavianator.com>        #
-#                                                                          #
-# Permission to use, copy, modify, and/or distribute this software for any #
-# purpose with or without fee is hereby granted.                           #
-#                                                                          #
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES #
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         #
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  #
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   #
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    #
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  #
-# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           #
-############################################################################
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
 
 set -euP
 umask 022
diff --git a/tests/trie.c b/tests/trie.c
index 88e92da..c2af18a 100644
--- a/tests/trie.c
+++ b/tests/trie.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020-2022 Tavian Barnes <tavianator@tavianator.com>        *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #undef NDEBUG
 
diff --git a/tests/xtimegm.c b/tests/xtimegm.c
index d774b9e..bab64ba 100644
--- a/tests/xtimegm.c
+++ b/tests/xtimegm.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2020 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "../src/xtime.h"
 #include <stdbool.h>
diff --git a/tests/xtouch.c b/tests/xtouch.c
index 9a91ec7..506c73d 100644
--- a/tests/xtouch.c
+++ b/tests/xtouch.c
@@ -1,18 +1,5 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2022 Tavian Barnes <tavianator@tavianator.com>             *
- *                                                                          *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted.                           *
- *                                                                          *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
- ****************************************************************************/
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
 
 #include "../src/bfstd.h"
 #include "../src/xtime.h"
-- 
cgit v1.2.3


From 8368e139c176dcde3b125f4a180ff868729b1862 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 10 May 2023 15:42:54 -0400
Subject: config: s/BFS_COUNTOF/countof/

---
 src/config.h |  2 +-
 src/fsade.c  |  2 +-
 src/opt.c    | 16 ++++++++--------
 tests/trie.c |  2 +-
 4 files changed, 11 insertions(+), 11 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/config.h b/src/config.h
index e17f90b..60bc930 100644
--- a/src/config.h
+++ b/src/config.h
@@ -134,7 +134,7 @@
 /**
  * Get the length of an array.
  */
-#define BFS_COUNTOF(array) (sizeof(array) / sizeof(0[array]))
+#define countof(array) (sizeof(array) / sizeof(0[array]))
 
 // Lower bound on BFS_FLEX_SIZEOF()
 #define BFS_FLEX_LB(type, member, length) (offsetof(type, member) + sizeof(((type *)NULL)->member[0]) * (length))
diff --git a/src/fsade.c b/src/fsade.c
index aefbb75..4d67940 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -201,7 +201,7 @@ int bfs_check_acl(const struct BFTW *ftwbuf) {
 	const char *path = fake_at(ftwbuf);
 
 	int ret = -1, error = 0;
-	for (size_t i = 0; i < BFS_COUNTOF(acl_types) && ret <= 0; ++i) {
+	for (size_t i = 0; i < countof(acl_types) && ret <= 0; ++i) {
 		acl_type_t type = acl_types[i];
 
 		if (type == ACL_TYPE_DEFAULT && ftwbuf->type != BFS_DIR) {
diff --git a/src/opt.c b/src/opt.c
index 5505b7b..731dd10 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1154,21 +1154,21 @@ static const struct {
  * Look up the appropriate optimizer for an expression and call it.
  */
 static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs_expr *expr) {
-	for (size_t i = 0; i < BFS_COUNTOF(opt_pure); ++i) {
+	for (size_t i = 0; i < countof(opt_pure); ++i) {
 		if (opt_pure[i] == expr->eval_fn) {
 			expr->pure = true;
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_always_true); ++i) {
+	for (size_t i = 0; i < countof(opt_always_true); ++i) {
 		if (opt_always_true[i] == expr->eval_fn) {
 			expr->always_true = true;
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_always_false); ++i) {
+	for (size_t i = 0; i < countof(opt_always_false); ++i) {
 		if (opt_always_false[i] == expr->eval_fn) {
 			expr->always_false = true;
 			break;
@@ -1176,35 +1176,35 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 	}
 
 	expr->cost = FAST_COST;
-	for (size_t i = 0; i < BFS_COUNTOF(opt_costs); ++i) {
+	for (size_t i = 0; i < countof(opt_costs); ++i) {
 		if (opt_costs[i].eval_fn == expr->eval_fn) {
 			expr->cost = opt_costs[i].cost;
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_probs); ++i) {
+	for (size_t i = 0; i < countof(opt_probs); ++i) {
 		if (opt_probs[i].eval_fn == expr->eval_fn) {
 			expr->probability = opt_probs[i].probability;
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_preds); ++i) {
+	for (size_t i = 0; i < countof(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
 			infer_pred_facts(state, opt_preds[i].pred);
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_ranges); ++i) {
+	for (size_t i = 0; i < countof(opt_ranges); ++i) {
 		if (opt_ranges[i].eval_fn == expr->eval_fn) {
 			infer_icmp_facts(state, expr, opt_ranges[i].range);
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < BFS_COUNTOF(opt_fns); ++i) {
+	for (size_t i = 0; i < countof(opt_fns); ++i) {
 		if (opt_fns[i].eval_fn == expr->eval_fn) {
 			return opt_fns[i].opt_fn(state, expr);
 		}
diff --git a/tests/trie.c b/tests/trie.c
index c2af18a..ced14d4 100644
--- a/tests/trie.c
+++ b/tests/trie.c
@@ -38,7 +38,7 @@ const char *keys[] = {
 	">>>",
 };
 
-const size_t nkeys = BFS_COUNTOF(keys);
+const size_t nkeys = countof(keys);
 
 int main(void) {
 	struct trie trie;
-- 
cgit v1.2.3


From 59f87eed2b930af2f31fd1d1fb2589f80f426ee0 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 11 May 2023 10:12:35 -0400
Subject: config: Provide <stdalign.h> and <stdbool.h>

In anticipation of C23, since those headers won't be necessary any more.
---
 src/bfstd.c     | 1 -
 src/bfstd.h     | 2 +-
 src/bftw.c      | 1 -
 src/color.c     | 1 -
 src/color.h     | 1 -
 src/config.h    | 6 +++++-
 src/ctx.h       | 2 +-
 src/diag.h      | 1 -
 src/dir.c       | 2 --
 src/eval.h      | 2 +-
 src/exec.c      | 1 -
 src/expr.h      | 2 +-
 src/fsade.h     | 1 -
 src/main.c      | 2 +-
 src/mtab.c      | 1 -
 src/mtab.h      | 2 +-
 src/opt.c       | 1 -
 src/parse.c     | 1 -
 src/printf.c    | 1 -
 src/pwcache.c   | 2 +-
 src/stat.c      | 1 -
 src/trie.c      | 1 -
 src/trie.h      | 1 -
 src/xspawn.c    | 1 -
 src/xtime.c     | 2 +-
 tests/xtimegm.c | 2 +-
 tests/xtouch.c  | 2 +-
 27 files changed, 15 insertions(+), 28 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/bfstd.c b/src/bfstd.c
index 1dc322b..932f2c4 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -9,7 +9,6 @@
 #include <fcntl.h>
 #include <langinfo.h>
 #include <nl_types.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/bfstd.h b/src/bfstd.h
index 028e4e6..e4fd1f1 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -8,7 +8,7 @@
 #ifndef BFS_BFSTD_H
 #define BFS_BFSTD_H
 
-#include <stdbool.h>
+#include "config.h"
 #include <stddef.h>
 
 // #include <errno.h>
diff --git a/src/bftw.c b/src/bftw.c
index 56701a7..14805de 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -28,7 +28,6 @@
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
diff --git a/src/color.c b/src/color.c
index 589e631..eeadf98 100644
--- a/src/color.c
+++ b/src/color.c
@@ -15,7 +15,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/color.h b/src/color.h
index 737c34b..3db2b07 100644
--- a/src/color.h
+++ b/src/color.h
@@ -10,7 +10,6 @@
 
 #include "config.h"
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stdio.h>
 
 /**
diff --git a/src/config.h b/src/config.h
index 229bafb..4408feb 100644
--- a/src/config.h
+++ b/src/config.h
@@ -8,9 +8,13 @@
 #ifndef BFS_CONFIG_H
 #define BFS_CONFIG_H
 
-#include <stdbool.h>
 #include <stddef.h>
 
+#if __STDC_VERSION__ < 202311L
+#  include <stdalign.h>
+#  include <stdbool.h>
+#endif
+
 // bfs packaging configuration
 
 #ifndef BFS_COMMAND
diff --git a/src/ctx.h b/src/ctx.h
index 4c748b7..0dc9f08 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -9,8 +9,8 @@
 #define BFS_CTX_H
 
 #include "bftw.h"
+#include "config.h"
 #include "trie.h"
-#include <stdbool.h>
 #include <stddef.h>
 #include <sys/resource.h>
 #include <time.h>
diff --git a/src/diag.h b/src/diag.h
index 2952e30..987d4b4 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -11,7 +11,6 @@
 #include "ctx.h"
 #include "config.h"
 #include <stdarg.h>
-#include <stdbool.h>
 
 struct bfs_expr;
 
diff --git a/src/dir.c b/src/dir.c
index eb6e3e0..30db5df 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -8,8 +8,6 @@
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <stdalign.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
diff --git a/src/eval.h b/src/eval.h
index 3d70319..bdb9440 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -9,7 +9,7 @@
 #ifndef BFS_EVAL_H
 #define BFS_EVAL_H
 
-#include <stdbool.h>
+#include "config.h"
 
 struct bfs_ctx;
 struct bfs_expr;
diff --git a/src/exec.c b/src/exec.c
index 6bde1c1..7f22d36 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -14,7 +14,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/expr.h b/src/expr.h
index 1628cac..356689d 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -9,9 +9,9 @@
 #define BFS_EXPR_H
 
 #include "color.h"
+#include "config.h"
 #include "eval.h"
 #include "stat.h"
-#include <stdbool.h>
 #include <stddef.h>
 #include <sys/types.h>
 #include <time.h>
diff --git a/src/fsade.h b/src/fsade.h
index 557da26..0d9ecaf 100644
--- a/src/fsade.h
+++ b/src/fsade.h
@@ -10,7 +10,6 @@
 #define BFS_FSADE_H
 
 #include "config.h"
-#include <stdbool.h>
 
 #define BFS_CAN_CHECK_ACL BFS_USE_SYS_ACL_H
 
diff --git a/src/main.c b/src/main.c
index 4f99580..24a5035 100644
--- a/src/main.c
+++ b/src/main.c
@@ -40,13 +40,13 @@
  */
 
 #include "bfstd.h"
+#include "config.h"
 #include "ctx.h"
 #include "eval.h"
 #include "parse.h"
 #include <errno.h>
 #include <fcntl.h>
 #include <locale.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
diff --git a/src/mtab.c b/src/mtab.c
index 27f1743..1d1ad94 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -9,7 +9,6 @@
 #include "trie.h"
 #include <errno.h>
 #include <fcntl.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
diff --git a/src/mtab.h b/src/mtab.h
index 5dfdf6c..ca4372c 100644
--- a/src/mtab.h
+++ b/src/mtab.h
@@ -8,7 +8,7 @@
 #ifndef BFS_MTAB_H
 #define BFS_MTAB_H
 
-#include <stdbool.h>
+#include "config.h"
 
 struct bfs_stat;
 
diff --git a/src/opt.c b/src/opt.c
index 731dd10..4ce9425 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -39,7 +39,6 @@
 #include <errno.h>
 #include <limits.h>
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/src/parse.c b/src/parse.c
index 15f38a4..55f1e74 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -37,7 +37,6 @@
 #include <limits.h>
 #include <pwd.h>
 #include <stdarg.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/printf.c b/src/printf.c
index 454fbee..9ccc216 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -20,7 +20,6 @@
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
-#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/src/pwcache.c b/src/pwcache.c
index 5026dee..f52e4e1 100644
--- a/src/pwcache.c
+++ b/src/pwcache.c
@@ -2,12 +2,12 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "pwcache.h"
+#include "config.h"
 #include "darray.h"
 #include "trie.h"
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/src/stat.c b/src/stat.c
index f3d9046..7973d71 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -7,7 +7,6 @@
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <stdbool.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
diff --git a/src/trie.c b/src/trie.c
index bfe97e6..e0e00ff 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -86,7 +86,6 @@
 #include "list.h"
 #include <assert.h>
 #include <limits.h>
-#include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/trie.h b/src/trie.h
index 58974aa..6bd211e 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -5,7 +5,6 @@
 #define BFS_TRIE_H
 
 #include "config.h"
-#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 
diff --git a/src/xspawn.c b/src/xspawn.c
index a6d18a3..00fb76e 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -7,7 +7,6 @@
 #include "list.h"
 #include <errno.h>
 #include <fcntl.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/resource.h>
diff --git a/src/xtime.c b/src/xtime.c
index 82690d0..406d694 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -2,9 +2,9 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "xtime.h"
+#include "config.h"
 #include <errno.h>
 #include <limits.h>
-#include <stdbool.h>
 #include <stdlib.h>
 #include <sys/time.h>
 #include <time.h>
diff --git a/tests/xtimegm.c b/tests/xtimegm.c
index bab64ba..b2479b7 100644
--- a/tests/xtimegm.c
+++ b/tests/xtimegm.c
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "../src/xtime.h"
-#include <stdbool.h>
+#include "../src/config.h"
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/tests/xtouch.c b/tests/xtouch.c
index 7e29547..50416ba 100644
--- a/tests/xtouch.c
+++ b/tests/xtouch.c
@@ -2,10 +2,10 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "../src/bfstd.h"
+#include "../src/config.h"
 #include "../src/xtime.h"
 #include <errno.h>
 #include <fcntl.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-- 
cgit v1.2.3


From 526133c11eb9a26a4cffb20bcd10bcbb36d940de Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 18 May 2023 16:44:30 -0400
Subject: Switch from assert() to bfs_assert()/bfs_verify()

---
 src/bfstd.c   |   3 +-
 src/bftw.c    |  28 ++++++++--------
 src/color.c   |   5 ++-
 src/diag.c    |   3 +-
 src/dir.c     |   4 +--
 src/eval.c    |  11 +++----
 src/exec.c    |   7 ++--
 src/opt.c     |  13 ++++----
 src/parse.c   |   7 ++--
 src/printf.c  |   5 ++-
 src/trie.c    |  33 ++++++++++---------
 src/xregex.c  |   4 +--
 tests/bfstd.c |  13 ++++----
 tests/bit.c   | 100 +++++++++++++++++++++++++++++-----------------------------
 tests/trie.c  |  56 ++++++++++++++++----------------
 15 files changed, 140 insertions(+), 152 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/bfstd.c b/src/bfstd.c
index 91383a2..37f5276 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -5,7 +5,6 @@
 #include "config.h"
 #include "diag.h"
 #include "xregex.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <langinfo.h>
@@ -393,7 +392,7 @@ void close_quietly(int fd) {
 int xclose(int fd) {
 	int ret = close(fd);
 	if (ret != 0) {
-		assert(errno != EBADF);
+		bfs_verify(errno != EBADF);
 	}
 	return ret;
 }
diff --git a/src/bftw.c b/src/bftw.c
index 14805de..6ec5cfa 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -19,13 +19,13 @@
 #include "bftw.h"
 #include "bfstd.h"
 #include "config.h"
+#include "diag.h"
 #include "dir.h"
 #include "dstring.h"
 #include "list.h"
 #include "mtab.h"
 #include "stat.h"
 #include "trie.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -114,7 +114,7 @@ static void bftw_cache_remove(struct bftw_cache *cache, struct bftw_file *file)
 
 /** Close a bftw_file. */
 static void bftw_file_close(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(file->fd >= 0);
+	bfs_assert(file->fd >= 0);
 
 	if (LIST_ATTACHED(cache, file, lru)) {
 		bftw_cache_remove(cache, file);
@@ -137,7 +137,7 @@ static int bftw_cache_pop(struct bftw_cache *cache) {
 
 /** Add a bftw_file to the cache. */
 static int bftw_cache_add(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(file->fd >= 0);
+	bfs_assert(file->fd >= 0);
 
 	if (cache->capacity == 0 && bftw_cache_pop(cache) != 0) {
 		bftw_file_close(cache, file);
@@ -145,7 +145,7 @@ static int bftw_cache_add(struct bftw_cache *cache, struct bftw_file *file) {
 		return -1;
 	}
 
-	assert(cache->capacity > 0);
+	bfs_assert(cache->capacity > 0);
 	--cache->capacity;
 
 	LIST_INSERT(cache, cache->target, file, lru);
@@ -169,9 +169,9 @@ static size_t bftw_child_nameoff(const struct bftw_file *parent) {
 
 /** Destroy a cache. */
 static void bftw_cache_destroy(struct bftw_cache *cache) {
-	assert(!cache->head);
-	assert(!cache->tail);
-	assert(!cache->target);
+	bfs_assert(!cache->head);
+	bfs_assert(!cache->tail);
+	bfs_assert(!cache->target);
 }
 
 /** Create a new bftw_file. */
@@ -230,7 +230,7 @@ static struct bftw_file *bftw_file_new(struct bftw_file *parent, const char *nam
  *         The opened file descriptor, or negative on error.
  */
 static int bftw_file_openat(struct bftw_cache *cache, struct bftw_file *file, struct bftw_file *base, const char *at_path) {
-	assert(file->fd < 0);
+	bfs_assert(file->fd < 0);
 
 	int at_fd = AT_FDCWD;
 	if (base) {
@@ -332,7 +332,7 @@ static struct bfs_dir *bftw_file_opendir(struct bftw_cache *cache, struct bftw_f
 
 /** Free a bftw_file. */
 static void bftw_file_free(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(file->refcount == 0);
+	bfs_assert(file->refcount == 0);
 
 	if (file->fd >= 0) {
 		bftw_file_close(cache, file);
@@ -770,7 +770,7 @@ static enum bftw_action bftw_call_back(struct bftw_state *state, const char *nam
 
 /** Pop a directory to read from the queue. */
 static bool bftw_pop_dir(struct bftw_state *state) {
-	assert(!state->file);
+	bfs_assert(!state->file);
 
 	if (!state->dirs.head) {
 		return false;
@@ -787,7 +787,7 @@ static bool bftw_pop_dir(struct bftw_state *state) {
 
 /** Pop a file to visit from the queue. */
 static bool bftw_pop_file(struct bftw_state *state) {
-	assert(!state->file);
+	bfs_assert(!state->file);
 
 	state->file = state->files.head;
 	if (state->file) {
@@ -802,8 +802,8 @@ static bool bftw_pop_file(struct bftw_state *state) {
  * Open the current directory.
  */
 static int bftw_opendir(struct bftw_state *state) {
-	assert(!state->dir);
-	assert(!state->de);
+	bfs_assert(!state->dir);
+	bfs_assert(!state->de);
 
 	state->direrror = 0;
 
@@ -863,7 +863,7 @@ static int bftw_gc(struct bftw_state *state, enum bftw_gc_flags flags) {
 
 	if (state->dir) {
 		struct bftw_file *file = state->file;
-		assert(file && file->fd >= 0);
+		bfs_assert(file && file->fd >= 0);
 
 		if (file->refcount > 1) {
 			// Keep the fd around if any subdirectories exist
diff --git a/src/color.c b/src/color.c
index 43ea9a4..a723084 100644
--- a/src/color.c
+++ b/src/color.c
@@ -12,7 +12,6 @@
 #include "fsade.h"
 #include "stat.h"
 #include "trie.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
@@ -699,7 +698,7 @@ static int print_colored(CFILE *cfile, const char *esc, const char *str, size_t
 /** Find the offset of the first broken path component. */
 static ssize_t first_broken_offset(const char *path, const struct BFTW *ftwbuf, enum bfs_stat_flags flags, size_t max) {
 	ssize_t ret = max;
-	assert(ret >= 0);
+	bfs_assert(ret >= 0);
 
 	if (bftw_type(ftwbuf, flags) != BFS_ERROR) {
 		goto out;
@@ -1100,7 +1099,7 @@ static int cbuff(CFILE *cfile, const char *format, ...) {
 }
 
 int cvfprintf(CFILE *cfile, const char *format, va_list args) {
-	assert(dstrlen(cfile->buffer) == 0);
+	bfs_assert(dstrlen(cfile->buffer) == 0);
 
 	int ret = -1;
 	if (cvbuff(cfile, format, args) == 0) {
diff --git a/src/diag.c b/src/diag.c
index d7ffaa6..04e3678 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -6,7 +6,6 @@
 #include "ctx.h"
 #include "color.h"
 #include "expr.h"
-#include <assert.h>
 #include <errno.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -117,7 +116,7 @@ static bool highlight_expr_recursive(const struct bfs_ctx *ctx, const struct bfs
 	for (size_t i = 0; i < ctx->argc; ++i) {
 		if (&ctx->argv[i] == expr->argv) {
 			for (size_t j = 0; j < expr->argc; ++j) {
-				assert(i + j < ctx->argc);
+				bfs_assert(i + j < ctx->argc);
 				args[i + j] = true;
 				ret = true;
 			}
diff --git a/src/dir.c b/src/dir.c
index 6739f10..d9ee63b 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -4,7 +4,7 @@
 #include "dir.h"
 #include "bfstd.h"
 #include "config.h"
-#include <assert.h>
+#include "diag.h"
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -249,7 +249,7 @@ int bfs_closedir(struct bfs_dir *dir) {
 	int ret = xclose(dir->fd);
 #else
 	int ret = closedir(dir->dir);
-	assert(ret == 0 || errno != EBADF);
+	bfs_verify(ret == 0 || errno != EBADF);
 #endif
 	free(dir);
 	return ret;
diff --git a/src/eval.c b/src/eval.c
index 6cad3a9..342debd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -26,7 +26,6 @@
 #include "trie.h"
 #include "xregex.h"
 #include "xtime.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ -990,7 +989,7 @@ static bool eval_expr(struct bfs_expr *expr, struct bfs_eval *state) {
 		}
 	}
 
-	assert(!state->quit);
+	bfs_assert(!state->quit);
 
 	bool ret = expr->eval_fn(expr, state);
 
@@ -1006,10 +1005,10 @@ static bool eval_expr(struct bfs_expr *expr, struct bfs_eval *state) {
 	}
 
 	if (bfs_expr_never_returns(expr)) {
-		assert(state->quit);
+		bfs_assert(state->quit);
 	} else if (!state->quit) {
-		assert(!expr->always_true || ret);
-		assert(!expr->always_false || !ret);
+		bfs_assert(!expr->always_true || ret);
+		bfs_assert(!expr->always_false || !ret);
 	}
 
 	return ret;
@@ -1511,7 +1510,7 @@ static void dump_bftw_flags(enum bftw_flags flags) {
 	DEBUG_FLAG(flags, BFTW_SORT);
 	DEBUG_FLAG(flags, BFTW_BUFFER);
 
-	assert(!flags);
+	bfs_assert(flags == 0, "Missing bftw flag 0x%X", flags);
 }
 
 /**
diff --git a/src/exec.c b/src/exec.c
index 7f22d36..5912ad6 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -10,7 +10,6 @@
 #include "diag.h"
 #include "dstring.h"
 #include "xspawn.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
@@ -276,12 +275,12 @@ static void bfs_exec_free_arg(char *arg, const char *tmpl) {
 
 /** Open a file to use as the working directory. */
 static int bfs_exec_openwd(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
-	assert(execbuf->wd_fd < 0);
-	assert(!execbuf->wd_path);
+	bfs_assert(execbuf->wd_fd < 0);
+	bfs_assert(!execbuf->wd_path);
 
 	if (ftwbuf->at_fd != AT_FDCWD) {
 		// Rely on at_fd being the immediate parent
-		assert(xbaseoff(ftwbuf->at_path) == 0);
+		bfs_assert(xbaseoff(ftwbuf->at_path) == 0);
 
 		execbuf->wd_fd = ftwbuf->at_fd;
 		if (!(execbuf->flags & BFS_EXEC_MULTI)) {
diff --git a/src/opt.c b/src/opt.c
index 4ce9425..4699af4 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -35,7 +35,6 @@
 #include "exec.h"
 #include "expr.h"
 #include "pwcache.h"
-#include <assert.h>
 #include <errno.h>
 #include <limits.h>
 #include <stdarg.h>
@@ -308,7 +307,7 @@ struct opt_state {
 /** Log an optimization. */
 BFS_FORMATTER(3, 4)
 static bool opt_debug(const struct opt_state *state, int level, const char *format, ...) {
-	assert(state->ctx->optlevel >= level);
+	bfs_assert(state->ctx->optlevel >= level);
 
 	if (bfs_debug(state->ctx, DEBUG_OPT, "${cyn}-O%d${rs}: ", level)) {
 		va_list args;
@@ -387,7 +386,7 @@ static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr
 		has_parent = false;
 	}
 
-	assert(expr->eval_fn == eval_and || expr->eval_fn == eval_or);
+	bfs_assert(expr->eval_fn == eval_and || expr->eval_fn == eval_or);
 	if (expr->eval_fn == eval_and) {
 		expr->eval_fn = eval_or;
 		expr->argv = &fake_or_arg;
@@ -446,7 +445,7 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
  * Optimize a negation.
  */
 static struct bfs_expr *optimize_not_expr(const struct opt_state *state, struct bfs_expr *expr) {
-	assert(expr->eval_fn == eval_not);
+	bfs_assert(expr->eval_fn == eval_not);
 
 	struct bfs_expr *rhs = expr->rhs;
 
@@ -498,7 +497,7 @@ fail:
 
 /** Optimize a conjunction. */
 static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct bfs_expr *expr) {
-	assert(expr->eval_fn == eval_and);
+	bfs_assert(expr->eval_fn == eval_and);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
@@ -569,7 +568,7 @@ fail:
 
 /** Optimize a disjunction. */
 static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct bfs_expr *expr) {
-	assert(expr->eval_fn == eval_or);
+	bfs_assert(expr->eval_fn == eval_or);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
@@ -673,7 +672,7 @@ static struct bfs_expr *ignore_result(const struct opt_state *state, struct bfs_
 
 /** Optimize a comma expression. */
 static struct bfs_expr *optimize_comma_expr(const struct opt_state *state, struct bfs_expr *expr) {
-	assert(expr->eval_fn == eval_comma);
+	bfs_assert(expr->eval_fn == eval_comma);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
diff --git a/src/parse.c b/src/parse.c
index 807892c..1a04e68 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -29,7 +29,6 @@
 #include "xregex.h"
 #include "xspawn.h"
 #include "xtime.h"
-#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ -134,7 +133,7 @@ static struct bfs_expr *new_unary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *rh
 
 	expr->lhs = NULL;
 	expr->rhs = rhs;
-	assert(bfs_expr_is_parent(expr));
+	bfs_assert(bfs_expr_is_parent(expr));
 
 	expr->persistent_fds = rhs->persistent_fds;
 	expr->ephemeral_fds = rhs->ephemeral_fds;
@@ -154,7 +153,7 @@ static struct bfs_expr *new_binary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *l
 
 	expr->lhs = lhs;
 	expr->rhs = rhs;
-	assert(bfs_expr_is_parent(expr));
+	bfs_assert(bfs_expr_is_parent(expr));
 
 	expr->persistent_fds = lhs->persistent_fds + rhs->persistent_fds;
 	if (lhs->ephemeral_fds > rhs->ephemeral_fds) {
@@ -263,7 +262,7 @@ static void init_highlight(const struct bfs_ctx *ctx, bool *args) {
 static void highlight_args(const struct bfs_ctx *ctx, char **argv, size_t argc, bool *args) {
 	size_t i = argv - ctx->argv;
 	for (size_t j = 0; j < argc; ++j) {
-		assert(i + j < ctx->argc);
+		bfs_assert(i + j < ctx->argc);
 		args[i + j] = true;
 	}
 }
diff --git a/src/printf.c b/src/printf.c
index 9ccc216..6520d2d 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -16,7 +16,6 @@
 #include "pwcache.h"
 #include "stat.h"
 #include "xtime.h"
-#include <assert.h>
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
@@ -74,7 +73,7 @@ static bool should_color(CFILE *cfile, const struct bfs_printf *directive) {
 #define BFS_PRINTF_BUF(buf, format, ...) \
 	char buf[256]; \
 	int ret = snprintf(buf, sizeof(buf), format, __VA_ARGS__); \
-	assert(ret >= 0 && (size_t)ret < sizeof(buf)); \
+	bfs_assert(ret >= 0 && (size_t)ret < sizeof(buf)); \
 	(void)ret
 
 /**
@@ -190,7 +189,7 @@ static int bfs_printf_strftime(CFILE *cfile, const struct bfs_printf *directive,
 		break;
 	}
 
-	assert(ret >= 0 && (size_t)ret < sizeof(buf));
+	bfs_assert(ret >= 0 && (size_t)ret < sizeof(buf));
 	(void)ret;
 
 	return dyn_fprintf(cfile->file, directive, buf);
diff --git a/src/trie.c b/src/trie.c
index a2921de..8543eb1 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -86,7 +86,6 @@
 #include "config.h"
 #include "diag.h"
 #include "list.h"
-#include <assert.h>
 #include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -139,27 +138,27 @@ static bool trie_is_leaf(uintptr_t ptr) {
 
 /** Decode a pointer to a leaf. */
 static struct trie_leaf *trie_decode_leaf(uintptr_t ptr) {
-	assert(trie_is_leaf(ptr));
+	bfs_assert(trie_is_leaf(ptr));
 	return (struct trie_leaf *)(ptr ^ 1);
 }
 
 /** Encode a pointer to a leaf. */
 static uintptr_t trie_encode_leaf(const struct trie_leaf *leaf) {
 	uintptr_t ptr = (uintptr_t)leaf ^ 1;
-	assert(trie_is_leaf(ptr));
+	bfs_assert(trie_is_leaf(ptr));
 	return ptr;
 }
 
 /** Decode a pointer to an internal node. */
 static struct trie_node *trie_decode_node(uintptr_t ptr) {
-	assert(!trie_is_leaf(ptr));
+	bfs_assert(!trie_is_leaf(ptr));
 	return (struct trie_node *)ptr;
 }
 
 /** Encode a pointer to an internal node. */
 static uintptr_t trie_encode_node(const struct trie_node *node) {
 	uintptr_t ptr = (uintptr_t)node;
-	assert(!trie_is_leaf(ptr));
+	bfs_assert(!trie_is_leaf(ptr));
 	return ptr;
 }
 
@@ -341,9 +340,9 @@ static void trie_leaf_free(struct trie *trie, struct trie_leaf *leaf) {
 /** Compute the size of a trie node with a certain number of children. */
 static size_t trie_node_size(unsigned int size) {
 	// Empty nodes aren't supported
-	assert(size > 0);
+	bfs_assert(size > 0);
 	// Node size must be a power of two
-	assert(has_single_bit(size));
+	bfs_assert(has_single_bit(size));
 
 	return flex_sizeof(struct trie_node, children, size);
 }
@@ -435,7 +434,7 @@ static struct trie_leaf *trie_node_insert(struct trie *trie, uintptr_t *ptr, str
 	unsigned int bit = 1U << nibble;
 
 	// The child must not already be present
-	assert(!(node->bitmap & bit));
+	bfs_assert(!(node->bitmap & bit));
 	node->bitmap |= bit;
 
 	unsigned int target = count_ones(node->bitmap & (bit - 1));
@@ -474,7 +473,7 @@ static struct trie_leaf *trie_node_insert(struct trie *trie, uintptr_t *ptr, str
 static uintptr_t *trie_jump(uintptr_t *ptr, const char *key, size_t *offset) {
 	// We only ever need to jump to leaf nodes, since internal nodes are
 	// guaranteed to be within OFFSET_MAX anyway
-	assert(trie_is_leaf(*ptr));
+	bfs_assert(trie_is_leaf(*ptr));
 
 	struct trie_node *node = malloc(trie_node_size(1));
 	if (!node) {
@@ -512,7 +511,7 @@ static uintptr_t *trie_jump(uintptr_t *ptr, const char *key, size_t *offset) {
 static struct trie_leaf *trie_split(struct trie *trie, uintptr_t *ptr, struct trie_leaf *leaf, struct trie_leaf *rep, size_t offset, size_t mismatch) {
 	unsigned char key_nibble = trie_key_nibble(leaf->key, mismatch);
 	unsigned char rep_nibble = trie_key_nibble(rep->key, mismatch);
-	assert(key_nibble != rep_nibble);
+	bfs_assert(key_nibble != rep_nibble);
 
 	struct trie_node *node = malloc(trie_node_size(2));
 	if (!node) {
@@ -570,11 +569,11 @@ static struct trie_leaf *trie_insert_mem_impl(struct trie *trie, const void *key
 		unsigned char nibble = trie_key_nibble(key, offset);
 		unsigned int bit = 1U << nibble;
 		if (node->bitmap & bit) {
-			assert(offset < mismatch);
+			bfs_assert(offset < mismatch);
 			unsigned int index = count_ones(node->bitmap & (bit - 1));
 			ptr = &node->children[index];
 		} else {
-			assert(offset == mismatch);
+			bfs_assert(offset == mismatch);
 			return trie_node_insert(trie, ptr, leaf, nibble);
 		}
 	}
@@ -600,7 +599,7 @@ static void trie_free_singletons(struct trie *trie, uintptr_t ptr) {
 		struct trie_node *node = trie_decode_node(ptr);
 
 		// Make sure the bitmap is a power of two, i.e. it has just one child
-		assert(has_single_bit(node->bitmap));
+		bfs_assert(has_single_bit(node->bitmap));
 
 		ptr = node->children[0];
 		free(node);
@@ -651,12 +650,12 @@ static void trie_remove_impl(struct trie *trie, struct trie_leaf *leaf) {
 	while (!trie_is_leaf(*child)) {
 		struct trie_node *node = trie_decode_node(*child);
 		offset += node->offset;
-		assert((offset >> 1) < leaf->length);
+		bfs_assert((offset >> 1) < leaf->length);
 
 		unsigned char nibble = trie_key_nibble(leaf->key, offset);
 		unsigned int bit = 1U << nibble;
 		unsigned int bitmap = node->bitmap;
-		assert(bitmap & bit);
+		bfs_assert(bitmap & bit);
 		unsigned int index = count_ones(bitmap & (bit - 1));
 
 		// Advance the parent pointer, unless this node had only one child
@@ -669,7 +668,7 @@ static void trie_remove_impl(struct trie *trie, struct trie_leaf *leaf) {
 		child = &node->children[index];
 	}
 
-	assert(trie_decode_leaf(*child) == leaf);
+	bfs_assert(trie_decode_leaf(*child) == leaf);
 
 	if (!parent) {
 		trie_free_singletons(trie, trie->root);
@@ -683,7 +682,7 @@ static void trie_remove_impl(struct trie *trie, struct trie_leaf *leaf) {
 
 	node->bitmap ^= child_bit;
 	unsigned int parent_size = count_ones(node->bitmap);
-	assert(parent_size > 0);
+	bfs_assert(parent_size > 0);
 	if (parent_size == 1 && trie_collapse_node(parent, node, child_index) == 0) {
 		return;
 	}
diff --git a/src/xregex.c b/src/xregex.c
index a7153b7..1143f23 100644
--- a/src/xregex.c
+++ b/src/xregex.c
@@ -3,7 +3,7 @@
 
 #include "xregex.h"
 #include "config.h"
-#include <assert.h>
+#include "diag.h"
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
@@ -140,7 +140,7 @@ int bfs_regcomp(struct bfs_regex **preg, const char *pattern, enum bfs_regex_typ
 		syntax = ONIG_SYNTAX_GREP;
 		break;
 	}
-	assert(syntax);
+	bfs_assert(syntax);
 
 	OnigOptionType options = syntax->options;
 	if (flags & BFS_REGEX_ICASE) {
diff --git a/tests/bfstd.c b/tests/bfstd.c
index a986a23..1812a00 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -1,10 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
-#undef NDEBUG
 #include "../src/bfstd.h"
 #include "../src/config.h"
-#include <assert.h>
+#include "../src/diag.h"
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -39,11 +38,11 @@ int main(void) {
 		alignas(64) int foo;
 		int bar[];
 	};
-	assert(flex_sizeof(struct flexible, bar, 0) >= sizeof(struct flexible));
-	assert(flex_sizeof(struct flexible, bar, 16) % alignof(struct flexible) == 0);
-	assert(flex_sizeof(struct flexible, bar, SIZE_MAX / sizeof(int) + 1)
-	       == align_floor(alignof(struct flexible), SIZE_MAX));
-	assert(flex_sizeof_impl(8, 16, 4, 4, 1) == 16);
+	bfs_verify(flex_sizeof(struct flexible, bar, 0) >= sizeof(struct flexible));
+	bfs_verify(flex_sizeof(struct flexible, bar, 16) % alignof(struct flexible) == 0);
+	bfs_verify(flex_sizeof(struct flexible, bar, SIZE_MAX / sizeof(int) + 1)
+	           == align_floor(alignof(struct flexible), SIZE_MAX));
+	bfs_verify(flex_sizeof_impl(8, 16, 4, 4, 1) == 16);
 
 	// From man 3p basename
 	check_base_dir("usr", ".", "usr");
diff --git a/tests/bit.c b/tests/bit.c
index 7a7b0f3..cb339f4 100644
--- a/tests/bit.c
+++ b/tests/bit.c
@@ -1,11 +1,8 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
-#undef NDEBUG
-
 #include "../src/bit.h"
 #include "../src/diag.h"
-#include <assert.h>
 #include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -54,68 +51,71 @@ bfs_static_assert(UINTMAX_MAX == UWIDTH_MAX(UINTMAX_WIDTH));
 bfs_static_assert(INTMAX_MIN == IWIDTH_MIN(INTMAX_WIDTH));
 bfs_static_assert(INTMAX_MAX == IWIDTH_MAX(INTMAX_WIDTH));
 
+#define verify_eq(a, b) \
+	bfs_verify((a) == (b), "(0x%jX) %s != %s (0x%jX)", (uintmax_t)(a), #a, #b, (uintmax_t)(b))
+
 int main(void) {
-	assert(bswap((uint8_t)0x12) == 0x12);
-	assert(bswap((uint16_t)0x1234) == 0x3412);
-	assert(bswap((uint32_t)0x12345678) == 0x78563412);
-	assert(bswap((uint64_t)0x1234567812345678) == 0x7856341278563412);
-
-	assert(count_ones(0x0) == 0);
-	assert(count_ones(0x1) == 1);
-	assert(count_ones(0x2) == 1);
-	assert(count_ones(0x3) == 2);
-	assert(count_ones(0x137F) == 10);
-
-	assert(count_zeros(0) == INT_WIDTH);
-	assert(count_zeros(0L) == LONG_WIDTH);
-	assert(count_zeros(0LL) == LLONG_WIDTH);
-	assert(count_zeros((uint8_t)0) == 8);
-	assert(count_zeros((uint16_t)0) == 16);
-	assert(count_zeros((uint32_t)0) == 32);
-	assert(count_zeros((uint64_t)0) == 64);
-
-	assert(rotate_left((uint8_t)0xA1, 4) == 0x1A);
-	assert(rotate_left((uint16_t)0x1234, 12) == 0x4123);
-	assert(rotate_left((uint32_t)0x12345678, 20) == 0x67812345);
-	assert(rotate_left((uint32_t)0x12345678, 0) == 0x12345678);
-
-	assert(rotate_right((uint8_t)0xA1, 4) == 0x1A);
-	assert(rotate_right((uint16_t)0x1234, 12) == 0x2341);
-	assert(rotate_right((uint32_t)0x12345678, 20) == 0x45678123);
-	assert(rotate_right((uint32_t)0x12345678, 0) == 0x12345678);
+	verify_eq(bswap((uint8_t)0x12), 0x12);
+	verify_eq(bswap((uint16_t)0x1234), 0x3412);
+	verify_eq(bswap((uint32_t)0x12345678), 0x78563412);
+	verify_eq(bswap((uint64_t)0x1234567812345678), 0x7856341278563412);
+
+	verify_eq(count_ones(0x0), 0);
+	verify_eq(count_ones(0x1), 1);
+	verify_eq(count_ones(0x2), 1);
+	verify_eq(count_ones(0x3), 2);
+	verify_eq(count_ones(0x137F), 10);
+
+	verify_eq(count_zeros(0), INT_WIDTH);
+	verify_eq(count_zeros(0L), LONG_WIDTH);
+	verify_eq(count_zeros(0LL), LLONG_WIDTH);
+	verify_eq(count_zeros((uint8_t)0), 8);
+	verify_eq(count_zeros((uint16_t)0), 16);
+	verify_eq(count_zeros((uint32_t)0), 32);
+	verify_eq(count_zeros((uint64_t)0), 64);
+
+	verify_eq(rotate_left((uint8_t)0xA1, 4), 0x1A);
+	verify_eq(rotate_left((uint16_t)0x1234, 12), 0x4123);
+	verify_eq(rotate_left((uint32_t)0x12345678, 20), 0x67812345);
+	verify_eq(rotate_left((uint32_t)0x12345678, 0), 0x12345678);
+
+	verify_eq(rotate_right((uint8_t)0xA1, 4), 0x1A);
+	verify_eq(rotate_right((uint16_t)0x1234, 12), 0x2341);
+	verify_eq(rotate_right((uint32_t)0x12345678, 20), 0x45678123);
+	verify_eq(rotate_right((uint32_t)0x12345678, 0), 0x12345678);
 
 	for (int i = 0; i < 16; ++i) {
 		uint16_t n = (uint16_t)1 << i;
 		for (int j = i; j < 16; ++j) {
 			uint16_t m = (uint16_t)1 << j;
 			uint16_t nm = n | m;
-			assert(count_ones(nm) == 1 + (n != m));
-			assert(count_zeros(nm) == 15 - (n != m));
-			assert(leading_zeros(nm) == 15 - j);
-			assert(trailing_zeros(nm) == i);
-			assert(first_leading_one(nm) == j + 1);
-			assert(first_trailing_one(nm) == i + 1);
-			assert(bit_width(nm) == j + 1);
-			assert(bit_floor(nm) == m);
+			verify_eq(count_ones(nm), 1 + (n != m));
+			verify_eq(count_zeros(nm), 15 - (n != m));
+			verify_eq(leading_zeros(nm), 15 - j);
+			verify_eq(trailing_zeros(nm), i);
+			verify_eq(first_leading_one(nm), j + 1);
+			verify_eq(first_trailing_one(nm), i + 1);
+			verify_eq(bit_width(nm), j + 1);
+			verify_eq(bit_floor(nm), m);
 			if (n == m) {
-				assert(bit_ceil(nm) == m);
-				assert(has_single_bit(nm));
+				verify_eq(bit_ceil(nm), m);
+				bfs_verify(has_single_bit(nm));
 			} else {
 				if (j < 15) {
-					assert(bit_ceil(nm) == (m << 1));
+					verify_eq(bit_ceil(nm), (m << 1));
 				}
-				assert(!has_single_bit(nm));
+				bfs_verify(!has_single_bit(nm));
 			}
 		}
 	}
 
-	assert(leading_zeros((uint16_t)0) == 16);
-	assert(trailing_zeros((uint16_t)0) == 16);
-	assert(first_leading_one(0) == 0);
-	assert(first_trailing_one(0) == 0);
-	assert(bit_width(0) == 0);
-	assert(bit_floor(0) == 0);
-	assert(bit_ceil(0) == 1);
+	verify_eq(leading_zeros((uint16_t)0), 16);
+	verify_eq(trailing_zeros((uint16_t)0), 16);
+	verify_eq(first_leading_one(0), 0);
+	verify_eq(first_trailing_one(0), 0);
+	verify_eq(bit_width(0), 0);
+	verify_eq(bit_floor(0), 0);
+	verify_eq(bit_ceil(0), 1);
 
 	return EXIT_SUCCESS;
 }
diff --git a/tests/trie.c b/tests/trie.c
index ced14d4..e687f96 100644
--- a/tests/trie.c
+++ b/tests/trie.c
@@ -1,11 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
-#undef NDEBUG
-
 #include "../src/trie.h"
 #include "../src/config.h"
-#include <assert.h>
+#include "../src/diag.h"
 #include <stdlib.h>
 #include <string.h>
 
@@ -45,7 +43,7 @@ int main(void) {
 	trie_init(&trie);
 
 	for (size_t i = 0; i < nkeys; ++i) {
-		assert(!trie_find_str(&trie, keys[i]));
+		bfs_verify(!trie_find_str(&trie, keys[i]));
 
 		const char *prefix = NULL;
 		for (size_t j = 0; j < i; ++j) {
@@ -58,38 +56,38 @@ int main(void) {
 
 		struct trie_leaf *leaf = trie_find_prefix(&trie, keys[i]);
 		if (prefix) {
-			assert(leaf);
-			assert(strcmp(prefix, leaf->key) == 0);
+			bfs_verify(leaf);
+			bfs_verify(strcmp(prefix, leaf->key) == 0);
 		} else {
-			assert(!leaf);
+			bfs_verify(!leaf);
 		}
 
 		leaf = trie_insert_str(&trie, keys[i]);
-		assert(leaf);
-		assert(strcmp(keys[i], leaf->key) == 0);
-		assert(leaf->length == strlen(keys[i]) + 1);
+		bfs_verify(leaf);
+		bfs_verify(strcmp(keys[i], leaf->key) == 0);
+		bfs_verify(leaf->length == strlen(keys[i]) + 1);
 	}
 
 	{
 		size_t i = 0;
 		TRIE_FOR_EACH(&trie, leaf) {
-			assert(leaf == trie_find_str(&trie, keys[i]));
-			assert(!leaf->prev || leaf->prev->next == leaf);
-			assert(!leaf->next || leaf->next->prev == leaf);
+			bfs_verify(leaf == trie_find_str(&trie, keys[i]));
+			bfs_verify(!leaf->prev || leaf->prev->next == leaf);
+			bfs_verify(!leaf->next || leaf->next->prev == leaf);
 			++i;
 		}
-		assert(i == nkeys);
+		bfs_verify(i == nkeys);
 	}
 
 	for (size_t i = 0; i < nkeys; ++i) {
 		struct trie_leaf *leaf = trie_find_str(&trie, keys[i]);
-		assert(leaf);
-		assert(strcmp(keys[i], leaf->key) == 0);
-		assert(leaf->length == strlen(keys[i]) + 1);
+		bfs_verify(leaf);
+		bfs_verify(strcmp(keys[i], leaf->key) == 0);
+		bfs_verify(leaf->length == strlen(keys[i]) + 1);
 
 		trie_remove(&trie, leaf);
 		leaf = trie_find_str(&trie, keys[i]);
-		assert(!leaf);
+		bfs_verify(!leaf);
 
 		const char *postfix = NULL;
 		for (size_t j = i + 1; j < nkeys; ++j) {
@@ -102,33 +100,33 @@ int main(void) {
 
 		leaf = trie_find_postfix(&trie, keys[i]);
 		if (postfix) {
-			assert(leaf);
-			assert(strcmp(postfix, leaf->key) == 0);
+			bfs_verify(leaf);
+			bfs_verify(strcmp(postfix, leaf->key) == 0);
 		} else {
-			assert(!leaf);
+			bfs_verify(!leaf);
 		}
 	}
 
 	TRIE_FOR_EACH(&trie, leaf) {
-		assert(false);
+		bfs_verify(false);
 	}
 
 	// This tests the "jump" node handling on 32-bit platforms
 	size_t longsize = 1 << 20;
 	char *longstr = malloc(longsize);
-	assert(longstr);
+	bfs_verify(longstr);
 
 	memset(longstr, 0xAC, longsize);
-	assert(!trie_find_mem(&trie, longstr, longsize));
-	assert(trie_insert_mem(&trie, longstr, longsize));
+	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
+	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
 	memset(longstr + longsize/2, 0xAB, longsize/2);
-	assert(!trie_find_mem(&trie, longstr, longsize));
-	assert(trie_insert_mem(&trie, longstr, longsize));
+	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
+	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
 	memset(longstr, 0xAA, longsize/2);
-	assert(!trie_find_mem(&trie, longstr, longsize));
-	assert(trie_insert_mem(&trie, longstr, longsize));
+	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
+	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
 	free(longstr);
 	trie_destroy(&trie);
-- 
cgit v1.2.3


From a5550d478234efbb89d1c23ae3234bed626a47f6 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Fri, 16 Jun 2023 10:21:53 -0400
Subject: opt: Wait until purity is computed to update facts_when_impure

Since we moved purity out of the parser, side-effect detection has been
unnecessarily pessimistic due to this bug.  The fix restores warnings in
cases like

    $ bfs -false
    bfs: warning: This command won't do anything.

Fixes: 693b5f60dc9787d9237920cc0c87fe0e010194ee
---
 src/opt.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 4699af4..14de081 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1225,10 +1225,6 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 		return ret;
 	}
 
-	if (!bfs_expr_is_parent(expr) && !expr->pure) {
-		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
-	}
-
 	expr = optimize_expr_lookup(state, expr);
 	if (!expr) {
 		return NULL;
@@ -1247,6 +1243,8 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 				expr->ephemeral_fds = lhs->ephemeral_fds;
 			}
 		}
+	} else if (!expr->pure) {
+		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
 	}
 
 	if (expr->always_true) {
-- 
cgit v1.2.3


From 52de184ba28551734e1cb13233588504ab5f62ec Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 27 Sep 2023 12:11:15 -0400
Subject: Formatting fixes

---
 src/color.c     |  6 +++---
 src/ctx.c       |  1 -
 src/darray.c    |  4 ++--
 src/diag.c      |  8 ++++----
 src/diag.h      |  2 +-
 src/dstring.c   |  4 ++--
 src/eval.c      | 15 +++++++--------
 src/exec.c      | 16 ++++++++--------
 src/fsade.c     |  6 +++---
 src/ioq.c       |  2 +-
 src/opt.c       | 11 +++++------
 src/opt.h       |  1 -
 src/parse.c     | 45 ++++++++++++++++++++++-----------------------
 src/printf.c    | 46 +++++++++++++++++++++++-----------------------
 src/pwcache.c   |  1 -
 src/stat.c      |  2 +-
 src/trie.c      |  2 +-
 src/trie.h      |  4 ++--
 src/xregex.c    |  2 +-
 src/xspawn.c    |  2 +-
 src/xtime.c     | 12 ++++++------
 tests/bfstd.c   |  2 +-
 tests/mksock.c  |  2 +-
 tests/trie.c    |  4 ++--
 tests/xtimegm.c |  6 +++---
 25 files changed, 100 insertions(+), 106 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/color.c b/src/color.c
index 8d0b995..788d35d 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1143,11 +1143,11 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 	if (verbose) {
 		double rate = 0.0, time = 0.0;
 		if (expr->evaluations) {
-			rate = 100.0*expr->successes/expr->evaluations;
-			time = (1.0e9*expr->elapsed.tv_sec + expr->elapsed.tv_nsec)/expr->evaluations;
+			rate = 100.0 * expr->successes / expr->evaluations;
+			time = (1.0e9 * expr->elapsed.tv_sec + expr->elapsed.tv_nsec) / expr->evaluations;
 		}
 		if (cbuff(cfile, " [${ylw}%zu${rs}/${ylw}%zu${rs}=${ylw}%g%%${rs}; ${ylw}%gns${rs}]",
-		          expr->successes, expr->evaluations, rate, time)) {
+			    expr->successes, expr->evaluations, rate, time)) {
 			return -1;
 		}
 	}
diff --git a/src/ctx.c b/src/ctx.c
index 3a44e68..9a24a33 100644
--- a/src/ctx.c
+++ b/src/ctx.c
@@ -168,7 +168,6 @@ void bfs_ctx_flush(const struct bfs_ctx *ctx) {
 		} else if (cfile == ctx->cout) {
 			bfs_error(ctx, "(standard output): %m.\n");
 		}
-
 	}
 
 	// Flush the user/group caches, in case the executed command edits the
diff --git a/src/darray.c b/src/darray.c
index 42b8397..3e66a55 100644
--- a/src/darray.c
+++ b/src/darray.c
@@ -55,7 +55,7 @@ void *darray_push(void *da, const void *item, size_t size) {
 	size_t i = header->length++;
 	if (i >= capacity) {
 		capacity *= 2;
-		header = realloc(header, sizeof(*header) + capacity*size);
+		header = realloc(header, sizeof(*header) + capacity * size);
 		if (!header) {
 			// This failure will be detected by darray_check()
 			return da;
@@ -64,7 +64,7 @@ void *darray_push(void *da, const void *item, size_t size) {
 	}
 
 	char *data = darray_data(header);
-	memcpy(data + i*size, item, size);
+	memcpy(data + i * size, item, size);
 	return data;
 }
 
diff --git a/src/diag.c b/src/diag.c
index fa9db39..fa66525 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -4,9 +4,9 @@
 #include "diag.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "ctx.h"
 #include "color.h"
 #include "config.h"
+#include "ctx.h"
 #include "dstring.h"
 #include "expr.h"
 #include <errno.h>
@@ -31,14 +31,14 @@ void bfs_perror(const struct bfs_ctx *ctx, const char *str) {
 	bfs_error(ctx, "%s: %m.\n", str);
 }
 
-void bfs_error(const struct bfs_ctx *ctx, const char *format, ...)  {
+void bfs_error(const struct bfs_ctx *ctx, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
 	bfs_verror(ctx, format, args);
 	va_end(args);
 }
 
-bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...)  {
+bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
 	bool ret = bfs_vwarning(ctx, format, args);
@@ -46,7 +46,7 @@ bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...)  {
 	return ret;
 }
 
-bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...)  {
+bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
 	bool ret = bfs_vdebug(ctx, flag, format, args);
diff --git a/src/diag.h b/src/diag.h
index e019db0..fea8847 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -8,8 +8,8 @@
 #ifndef BFS_DIAG_H
 #define BFS_DIAG_H
 
-#include "ctx.h"
 #include "config.h"
+#include "ctx.h"
 #include <stdarg.h>
 
 /**
diff --git a/src/dstring.c b/src/dstring.c
index ef4e733..f947741 100644
--- a/src/dstring.c
+++ b/src/dstring.c
@@ -169,7 +169,7 @@ char *dstrprintf(const char *format, ...) {
 
 char *dstrvprintf(const char *format, va_list args) {
 	// Guess a capacity to try to avoid reallocating
-	dchar *str = dstralloc(2*strlen(format));
+	dchar *str = dstralloc(2 * strlen(format));
 	if (!str) {
 		return NULL;
 	}
@@ -195,7 +195,7 @@ int dstrcatf(dchar **str, const char *format, ...) {
 int dstrvcatf(dchar **str, const char *format, va_list args) {
 	// Guess a capacity to try to avoid calling vsnprintf() twice
 	size_t len = dstrlen(*str);
-	dstreserve(str, len + 2*strlen(format));
+	dstreserve(str, len + 2 * strlen(format));
 	size_t cap = dstrheader(*str)->capacity;
 
 	va_list copy;
diff --git a/src/eval.c b/src/eval.c
index 3550751..9f4896a 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -239,7 +239,7 @@ bool eval_time(const struct bfs_expr *expr, struct bfs_eval *state) {
 	time_t diff = timespec_diff(&expr->reftime, time);
 	switch (expr->time_unit) {
 	case BFS_DAYS:
-		diff /= 60*24;
+		diff /= 60 * 24;
 		fallthru;
 	case BFS_MINUTES:
 		diff /= 60;
@@ -271,7 +271,7 @@ bool eval_used(const struct bfs_expr *expr, struct bfs_eval *state) {
 		return false;
 	}
 
-	long long day_seconds = 60*60*24;
+	long long day_seconds = 60 * 60 * 24;
 	diff = (diff + day_seconds - 1) / day_seconds;
 	return bfs_expr_cmp(expr, diff);
 }
@@ -685,7 +685,7 @@ bool eval_fls(const struct bfs_expr *expr, struct bfs_eval *state) {
 
 	uintmax_t ino = statbuf->ino;
 	uintmax_t block_size = ctx->posixly_correct ? 512 : 1024;
-	uintmax_t blocks = ((uintmax_t)statbuf->blocks*BFS_STAT_BLKSIZE + block_size - 1)/block_size;
+	uintmax_t blocks = ((uintmax_t)statbuf->blocks * BFS_STAT_BLKSIZE + block_size - 1) / block_size;
 	char mode[11];
 	xstrmode(statbuf->mode, mode);
 	char acl = bfs_check_acl(ftwbuf) > 0 ? '+' : ' ';
@@ -721,8 +721,8 @@ bool eval_fls(const struct bfs_expr *expr, struct bfs_eval *state) {
 
 	time_t time = statbuf->mtime.tv_sec;
 	time_t now = ctx->now.tv_sec;
-	time_t six_months_ago = now - 6*30*24*60*60;
-	time_t tomorrow = now + 24*60*60;
+	time_t six_months_ago = now - 6 * 30 * 24 * 60 * 60;
+	time_t tomorrow = now + 24 * 60 * 60;
 	struct tm tm;
 	if (xlocaltime(&time, &tm) != 0) {
 		goto error;
@@ -823,7 +823,6 @@ bool eval_fprintx(const struct bfs_expr *expr, struct bfs_eval *state) {
 		++path;
 	}
 
-
 	if (fputc('\n', file) == EOF) {
 		goto error;
 	}
@@ -905,7 +904,7 @@ bool eval_size(const struct bfs_expr *expr, struct bfs_eval *state) {
 	};
 
 	off_t scale = scales[expr->size_unit];
-	off_t size = (statbuf->size + scale - 1)/scale; // Round up
+	off_t size = (statbuf->size + scale - 1) / scale; // Round up
 	return bfs_expr_cmp(expr, size);
 }
 
@@ -918,7 +917,7 @@ bool eval_sparse(const struct bfs_expr *expr, struct bfs_eval *state) {
 		return false;
 	}
 
-	blkcnt_t expected = (statbuf->size + BFS_STAT_BLKSIZE - 1)/BFS_STAT_BLKSIZE;
+	blkcnt_t expected = (statbuf->size + BFS_STAT_BLKSIZE - 1) / BFS_STAT_BLKSIZE;
 	return statbuf->blocks < expected;
 }
 
diff --git a/src/exec.c b/src/exec.c
index 7b55522..0e0d585 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -5,9 +5,9 @@
 #include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
-#include "ctx.h"
 #include "color.h"
 #include "config.h"
+#include "ctx.h"
 #include "diag.h"
 #include "dstring.h"
 #include "xspawn.h"
@@ -348,7 +348,7 @@ static int bfs_exec_spawn(const struct bfs_exec *execbuf) {
 
 	if (execbuf->flags & BFS_EXEC_MULTI) {
 		bfs_exec_debug(execbuf, "Executing '%s' ... [%zu arguments] (size %zu)\n",
-		               execbuf->argv[0], execbuf->argc - 1, execbuf->arg_size);
+			execbuf->argv[0], execbuf->argc - 1, execbuf->arg_size);
 	} else {
 		bfs_exec_debug(execbuf, "Executing '%s' ... [%zu arguments]\n", execbuf->argv[0], execbuf->argc - 1);
 	}
@@ -471,7 +471,7 @@ static bool bfs_exec_args_remain(const struct bfs_exec *execbuf) {
 static size_t bfs_exec_estimate_max(const struct bfs_exec *execbuf) {
 	size_t min = execbuf->arg_min;
 	size_t max = execbuf->arg_max;
-	return min + (max - min)/2;
+	return min + (max - min) / 2;
 }
 
 /** Update the ARG_MAX lower bound from a successful execution. */
@@ -486,7 +486,7 @@ static void bfs_exec_update_min(struct bfs_exec *execbuf) {
 
 		size_t estimate = bfs_exec_estimate_max(execbuf);
 		bfs_exec_debug(execbuf, "ARG_MAX between [%zu, %zu], trying %zu\n",
-		               execbuf->arg_min, execbuf->arg_max, estimate);
+			execbuf->arg_min, execbuf->arg_max, estimate);
 	}
 }
 
@@ -502,7 +502,7 @@ static size_t bfs_exec_update_max(struct bfs_exec *execbuf) {
 
 	// Trim a fraction off the max size to avoid repeated failures near the
 	// top end of the working range
-	size -= size/16;
+	size -= size / 16;
 	if (size < execbuf->arg_max) {
 		execbuf->arg_max = size;
 
@@ -515,7 +515,7 @@ static size_t bfs_exec_update_max(struct bfs_exec *execbuf) {
 	// Binary search for a more precise bound
 	size_t estimate = bfs_exec_estimate_max(execbuf);
 	bfs_exec_debug(execbuf, "ARG_MAX between [%zu, %zu], trying %zu\n",
-	               execbuf->arg_min, execbuf->arg_max, estimate);
+		execbuf->arg_min, execbuf->arg_max, estimate);
 	return estimate;
 }
 
@@ -589,7 +589,7 @@ static bool bfs_exec_would_overflow(const struct bfs_exec *execbuf, const char *
 	size_t next_size = execbuf->arg_size + bfs_exec_arg_size(arg);
 	if (next_size > arg_max) {
 		bfs_exec_debug(execbuf, "Command size (%zu) would exceed maximum (%zu), executing buffered command\n",
-		               next_size, arg_max);
+			next_size, arg_max);
 		return true;
 	}
 
@@ -601,7 +601,7 @@ static int bfs_exec_push(struct bfs_exec *execbuf, char *arg) {
 	execbuf->argv[execbuf->argc] = arg;
 
 	if (execbuf->argc + 1 >= execbuf->argv_cap) {
-		size_t cap = 2*execbuf->argv_cap;
+		size_t cap = 2 * execbuf->argv_cap;
 		char **argv = realloc(execbuf->argv, sizeof_array(char *, cap));
 		if (!argv) {
 			return -1;
diff --git a/src/fsade.c b/src/fsade.c
index 8dec5a8..cbff47b 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -3,9 +3,9 @@
 
 #include "fsade.h"
 #include "atomic.h"
-#include "config.h"
 #include "bfstd.h"
 #include "bftw.h"
+#include "config.h"
 #include "dir.h"
 #include "dstring.h"
 #include "sanity.h"
@@ -292,7 +292,7 @@ int bfs_check_xattrs(const struct BFTW *ftwbuf) {
 	ssize_t len;
 
 #if BFS_USE_SYS_EXTATTR_H
-	ssize_t (*extattr_list)(const char *, int, void*, size_t) =
+	ssize_t (*extattr_list)(const char *, int, void *, size_t) =
 		ftwbuf->type == BFS_LNK ? extattr_list_link : extattr_list_file;
 
 	len = extattr_list(path, EXTATTR_NAMESPACE_SYSTEM, NULL, 0);
@@ -331,7 +331,7 @@ int bfs_check_xattr_named(const struct BFTW *ftwbuf, const char *name) {
 	ssize_t len;
 
 #if BFS_USE_SYS_EXTATTR_H
-	ssize_t (*extattr_get)(const char *, int, const char *, void*, size_t) =
+	ssize_t (*extattr_get)(const char *, int, const char *, void *, size_t) =
 		ftwbuf->type == BFS_LNK ? extattr_get_link : extattr_get_file;
 
 	len = extattr_get(path, EXTATTR_NAMESPACE_SYSTEM, name, NULL, 0);
diff --git a/src/ioq.c b/src/ioq.c
index f7ca8c6..d3ba2de 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -9,8 +9,8 @@
 #include "config.h"
 #include "diag.h"
 #include "dir.h"
-#include "thread.h"
 #include "sanity.h"
+#include "thread.h"
 #include <assert.h>
 #include <errno.h>
 #include <pthread.h>
diff --git a/src/opt.c b/src/opt.c
index 14de081..77c2798 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -535,8 +535,8 @@ static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct
 	expr->pure = lhs->pure && rhs->pure;
 	expr->always_true = lhs->always_true && rhs->always_true;
 	expr->always_false = lhs->always_false || rhs->always_false;
-	expr->cost = lhs->cost + lhs->probability*rhs->cost;
-	expr->probability = lhs->probability*rhs->probability;
+	expr->cost = lhs->cost + lhs->probability * rhs->cost;
+	expr->probability = lhs->probability * rhs->probability;
 
 	return expr;
 }
@@ -606,8 +606,8 @@ static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct b
 	expr->pure = lhs->pure && rhs->pure;
 	expr->always_true = lhs->always_true || rhs->always_true;
 	expr->always_false = lhs->always_false && rhs->always_false;
-	expr->cost = lhs->cost + (1 - lhs->probability)*rhs->cost;
-	expr->probability = lhs->probability + rhs->probability - lhs->probability*rhs->probability;
+	expr->cost = lhs->cost + (1 - lhs->probability) * rhs->cost;
+	expr->probability = lhs->probability + rhs->probability - lhs->probability * rhs->probability;
 
 	return expr;
 }
@@ -1078,7 +1078,6 @@ static const struct {
 	{eval_xattrname, 0.01},
 };
 
-
 /**
  * Table of simple predicates.
  */
@@ -1331,7 +1330,7 @@ static bool reorder_expr_recursive(const struct opt_state *state, struct bfs_exp
 	if (expr->eval_fn == eval_and || expr->eval_fn == eval_or) {
 		if (lhs->pure && rhs->pure) {
 			float rhs_prob = expr->eval_fn == eval_and ? rhs->probability : 1.0 - rhs->probability;
-			float swapped_cost = rhs->cost + rhs_prob*lhs->cost;
+			float swapped_cost = rhs->cost + rhs_prob * lhs->cost;
 			ret |= reorder_expr(state, expr, swapped_cost);
 		}
 	}
diff --git a/src/opt.h b/src/opt.h
index 28cadb9..4aac129 100644
--- a/src/opt.h
+++ b/src/opt.h
@@ -21,4 +21,3 @@ struct bfs_ctx;
 int bfs_optimize(struct bfs_ctx *ctx);
 
 #endif // BFS_OPT_H
-
diff --git a/src/parse.c b/src/parse.c
index 3416d9e..7766a7b 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -41,8 +41,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/time.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
@@ -1797,10 +1797,10 @@ static int parse_reftime(const struct parser_state *state, struct bfs_expr *expr
 #else
 	int gmtoff = -timezone;
 #endif
-	int tz_hour = gmtoff/3600;
-	int tz_min = (labs(gmtoff)/60)%60;
+	int tz_hour = gmtoff / 3600;
+	int tz_min = (labs(gmtoff) / 60) % 60;
 	fprintf(stderr, "  - %04d-%02d-%02dT%02d:%02d:%02d%+03d:%02d\n",
-	        year, month, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, tz_hour, tz_min);
+		year, month, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, tz_hour, tz_min);
 
 	if (xgmtime(&state->now.tv_sec, &tm) != 0) {
 		parse_perror(state, "xgmtime()");
@@ -1832,8 +1832,8 @@ static struct bfs_expr *parse_newerxy(struct parser_state *state, int arg1, int
 	expr->stat_field = parse_newerxy_field(arg[6]);
 	if (!expr->stat_field) {
 		parse_expr_error(state, expr,
-		                 "For ${blu}-newer${bld}XY${rs}, ${bld}X${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, or ${bld}B${rs}, not ${err}%c${rs}.\n",
-		                 arg[6]);
+			"For ${blu}-newer${bld}XY${rs}, ${bld}X${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, or ${bld}B${rs}, not ${err}%c${rs}.\n",
+			arg[6]);
 		goto fail;
 	}
 
@@ -1845,8 +1845,8 @@ static struct bfs_expr *parse_newerxy(struct parser_state *state, int arg1, int
 		enum bfs_stat_field field = parse_newerxy_field(arg[7]);
 		if (!field) {
 			parse_expr_error(state, expr,
-			                 "For ${blu}-newer${bld}XY${rs}, ${bld}Y${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, ${bld}B${rs}, or ${bld}t${rs}, not ${err}%c${rs}.\n",
-			                 arg[7]);
+				"For ${blu}-newer${bld}XY${rs}, ${bld}Y${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, ${bld}B${rs}, or ${bld}t${rs}, not ${err}%c${rs}.\n",
+				arg[7]);
 			goto fail;
 		}
 
@@ -1855,7 +1855,6 @@ static struct bfs_expr *parse_newerxy(struct parser_state *state, int arg1, int
 			goto fail;
 		}
 
-
 		const struct timespec *reftime = bfs_stat_time(&sb, field);
 		if (!reftime) {
 			parse_expr_error(state, expr, "Couldn't get file %s.\n", bfs_stat_field_name(field));
@@ -1905,7 +1904,7 @@ static struct bfs_expr *parse_nohidden(struct parser_state *state, int arg1, int
  */
 static struct bfs_expr *parse_noleaf(struct parser_state *state, int arg1, int arg2) {
 	parse_warning(state, "${ex}%s${rs} does not apply the optimization that ${blu}%s${rs} inhibits.\n\n",
-	              BFS_COMMAND, state->argv[0]);
+		BFS_COMMAND, state->argv[0]);
 	return parse_nullary_option(state);
 }
 
@@ -2730,12 +2729,12 @@ static struct bfs_expr *parse_help(struct parser_state *state, int arg1, int arg
 	}
 
 	cfprintf(cout, "Usage: ${ex}%s${rs} [${cyn}flags${rs}...] [${mag}paths${rs}...] [${blu}expression${rs}...]\n\n",
-		 state->command);
+		state->command);
 
 	cfprintf(cout, "${ex}%s${rs} is compatible with ${ex}find${rs}, with some extensions. "
-		       "${cyn}Flags${rs} (${cyn}-H${rs}/${cyn}-L${rs}/${cyn}-P${rs} etc.), ${mag}paths${rs},\n"
-		       "and ${blu}expressions${rs} may be freely mixed in any order.\n\n",
-		 BFS_COMMAND);
+	               "${cyn}Flags${rs} (${cyn}-H${rs}/${cyn}-L${rs}/${cyn}-P${rs} etc.), ${mag}paths${rs},\n"
+	               "and ${blu}expressions${rs} may be freely mixed in any order.\n\n",
+		BFS_COMMAND);
 
 	cfprintf(cout, "${bld}Flags:${rs}\n\n");
 
@@ -2807,7 +2806,7 @@ static struct bfs_expr *parse_help(struct parser_state *state, int arg1, int arg
 	cfprintf(cout, "  ${blu}-ignore_readdir_race${rs}\n");
 	cfprintf(cout, "  ${blu}-noignore_readdir_race${rs}\n");
 	cfprintf(cout, "      Whether to report an error if ${ex}%s${rs} detects that the file tree is modified\n",
-	         BFS_COMMAND);
+		BFS_COMMAND);
 	cfprintf(cout, "      during the search (default: ${blu}-noignore_readdir_race${rs})\n");
 	cfprintf(cout, "  ${blu}-maxdepth${rs} ${bld}N${rs}\n");
 	cfprintf(cout, "  ${blu}-mindepth${rs} ${bld}N${rs}\n");
@@ -3462,14 +3461,14 @@ static struct bfs_expr *parse_whole_expr(struct parser_state *state) {
 
 	if (state->mount_arg && state->xdev_arg) {
 		parse_conflict_warning(state, state->mount_arg, 1, state->xdev_arg, 1,
-		                       "${blu}%s${rs} is redundant in the presence of ${blu}%s${rs}.\n\n",
-		                       state->xdev_arg[0], state->mount_arg[0]);
+			"${blu}%s${rs} is redundant in the presence of ${blu}%s${rs}.\n\n",
+			state->xdev_arg[0], state->mount_arg[0]);
 	}
 
 	if (state->ctx->warn && state->depth_arg && state->prune_arg) {
 		parse_conflict_warning(state, state->depth_arg, 1, state->prune_arg, 1,
-		                       "${blu}%s${rs} does not work in the presence of ${blu}%s${rs}.\n",
-		                       state->prune_arg[0], state->depth_arg[0]);
+			"${blu}%s${rs} does not work in the presence of ${blu}%s${rs}.\n",
+			state->prune_arg[0], state->depth_arg[0]);
 
 		if (state->interactive) {
 			bfs_warning(state->ctx, "Do you want to continue? ");
@@ -3483,8 +3482,8 @@ static struct bfs_expr *parse_whole_expr(struct parser_state *state) {
 
 	if (state->ok_expr && state->files0_stdin_arg) {
 		parse_conflict_error(state, state->ok_expr->argv, state->ok_expr->argc, state->files0_stdin_arg, 2,
-		                     "${blu}%s${rs} conflicts with ${blu}%s${rs} ${bld}%s${rs}.\n",
-		                     state->ok_expr->argv[0], state->files0_stdin_arg[0], state->files0_stdin_arg[1]);
+			"${blu}%s${rs} conflicts with ${blu}%s${rs} ${bld}%s${rs}.\n",
+			state->ok_expr->argv[0], state->files0_stdin_arg[0], state->files0_stdin_arg[1]);
 		goto fail;
 	}
 
@@ -3644,7 +3643,7 @@ void bfs_ctx_dump(const struct bfs_ctx *ctx, enum debug_flags flag) {
 static void dump_costs(const struct bfs_ctx *ctx) {
 	const struct bfs_expr *expr = ctx->expr;
 	bfs_debug(ctx, DEBUG_COST, "       Cost: ~${ylw}%g${rs}\n", expr->cost);
-	bfs_debug(ctx, DEBUG_COST, "Probability: ~${ylw}%g%%${rs}\n", 100.0*expr->probability);
+	bfs_debug(ctx, DEBUG_COST, "Probability: ~${ylw}%g%%${rs}\n", 100.0 * expr->probability);
 }
 
 struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
@@ -3654,7 +3653,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 		goto fail;
 	}
 
-	static char* default_argv[] = {BFS_COMMAND, NULL};
+	static char *default_argv[] = {BFS_COMMAND, NULL};
 	if (argc < 1) {
 		argc = 1;
 		argv = default_argv;
diff --git a/src/printf.c b/src/printf.c
index 5de5a28..98bcb0f 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -113,14 +113,14 @@ static int bfs_printf_ctime(CFILE *cfile, const struct bfs_printf *directive, co
 	}
 
 	BFS_PRINTF_BUF(buf, "%s %s %2d %.2d:%.2d:%.2d.%09ld0 %4d",
-	               days[tm.tm_wday],
-	               months[tm.tm_mon],
-	               tm.tm_mday,
-	               tm.tm_hour,
-	               tm.tm_min,
-	               tm.tm_sec,
-	               (long)ts->tv_nsec,
-	               1900 + tm.tm_year);
+		days[tm.tm_wday],
+		months[tm.tm_mon],
+		tm.tm_mday,
+		tm.tm_hour,
+		tm.tm_min,
+		tm.tm_sec,
+		(long)ts->tv_nsec,
+		1900 + tm.tm_year);
 
 	return dyn_fprintf(cfile->file, directive, buf);
 }
@@ -152,19 +152,19 @@ static int bfs_printf_strftime(CFILE *cfile, const struct bfs_printf *directive,
 		break;
 	case '+':
 		ret = snprintf(buf, sizeof(buf), "%4d-%.2d-%.2d+%.2d:%.2d:%.2d.%09ld0",
-		               1900 + tm.tm_year,
-		               tm.tm_mon + 1,
-		               tm.tm_mday,
-		               tm.tm_hour,
-		               tm.tm_min,
-		               tm.tm_sec,
-		               (long)ts->tv_nsec);
+			1900 + tm.tm_year,
+			tm.tm_mon + 1,
+			tm.tm_mday,
+			tm.tm_hour,
+			tm.tm_min,
+			tm.tm_sec,
+			(long)ts->tv_nsec);
 		break;
 	case 'k':
 		ret = snprintf(buf, sizeof(buf), "%2d", tm.tm_hour);
 		break;
 	case 'l':
-		ret = snprintf(buf, sizeof(buf), "%2d", (tm.tm_hour + 11)%12 + 1);
+		ret = snprintf(buf, sizeof(buf), "%2d", (tm.tm_hour + 11) % 12 + 1);
 		break;
 	case 's':
 		ret = snprintf(buf, sizeof(buf), "%lld", (long long)ts->tv_sec);
@@ -174,10 +174,10 @@ static int bfs_printf_strftime(CFILE *cfile, const struct bfs_printf *directive,
 		break;
 	case 'T':
 		ret = snprintf(buf, sizeof(buf), "%.2d:%.2d:%.2d.%09ld0",
-			       tm.tm_hour,
-			       tm.tm_min,
-			       tm.tm_sec,
-			       (long)ts->tv_nsec);
+			tm.tm_hour,
+			tm.tm_min,
+			tm.tm_sec,
+			(long)ts->tv_nsec);
 		break;
 
 	// POSIX strftime() features
@@ -202,7 +202,7 @@ static int bfs_printf_b(CFILE *cfile, const struct bfs_printf *directive, const
 		return -1;
 	}
 
-	uintmax_t blocks = ((uintmax_t)statbuf->blocks*BFS_STAT_BLKSIZE + 511)/512;
+	uintmax_t blocks = ((uintmax_t)statbuf->blocks * BFS_STAT_BLKSIZE + 511) / 512;
 	BFS_PRINTF_BUF(buf, "%ju", blocks);
 	return dyn_fprintf(cfile->file, directive, buf);
 }
@@ -338,7 +338,7 @@ static int bfs_printf_k(CFILE *cfile, const struct bfs_printf *directive, const
 		return -1;
 	}
 
-	uintmax_t blocks = ((uintmax_t)statbuf->blocks*BFS_STAT_BLKSIZE + 1023)/1024;
+	uintmax_t blocks = ((uintmax_t)statbuf->blocks * BFS_STAT_BLKSIZE + 1023) / 1024;
 	BFS_PRINTF_BUF(buf, "%ju", blocks);
 	return dyn_fprintf(cfile->file, directive, buf);
 }
@@ -452,7 +452,7 @@ static int bfs_printf_S(CFILE *cfile, const struct bfs_printf *directive, const
 	if (statbuf->size == 0 && statbuf->blocks == 0) {
 		sparsity = 1.0;
 	} else {
-		sparsity = (double)BFS_STAT_BLKSIZE*statbuf->blocks/statbuf->size;
+		sparsity = (double)BFS_STAT_BLKSIZE * statbuf->blocks / statbuf->size;
 	}
 	return dyn_fprintf(cfile->file, directive, sparsity);
 }
diff --git a/src/pwcache.c b/src/pwcache.c
index 0e2f5c1..c728ba9 100644
--- a/src/pwcache.c
+++ b/src/pwcache.c
@@ -4,7 +4,6 @@
 #include "pwcache.h"
 #include "alloc.h"
 #include "config.h"
-#include "darray.h"
 #include "trie.h"
 #include <errno.h>
 #include <grp.h>
diff --git a/src/stat.c b/src/stat.c
index e8f48ee..d7387c6 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -10,8 +10,8 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
-#include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 
 #if defined(STATX_BASIC_STATS) && (!__ANDROID__ || __ANDROID_API__ >= 30)
 #  define BFS_HAS_LIBC_STATX true
diff --git a/src/trie.c b/src/trie.c
index 77aa2d0..55544e6 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -700,7 +700,7 @@ static void trie_remove_impl(struct trie *trie, struct trie_leaf *leaf) {
 	}
 
 	if (child_index < parent_size) {
-		memmove(child, child + 1, (parent_size - child_index)*sizeof(*child));
+		memmove(child, child + 1, (parent_size - child_index) * sizeof(*child));
 	}
 
 	if (has_single_bit(parent_size)) {
diff --git a/src/trie.h b/src/trie.h
index 2f51db5..02088f1 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -4,8 +4,8 @@
 #ifndef BFS_TRIE_H
 #define BFS_TRIE_H
 
-#include "config.h"
 #include "alloc.h"
+#include "config.h"
 #include "list.h"
 #include <stddef.h>
 #include <stdint.h>
@@ -143,6 +143,6 @@ void trie_destroy(struct trie *trie);
  * Iterate over the leaves of a trie.
  */
 #define for_trie(leaf, trie) \
-	for_list(struct trie_leaf, leaf, trie)
+	for_list (struct trie_leaf, leaf, trie)
 
 #endif // BFS_TRIE_H
diff --git a/src/xregex.c b/src/xregex.c
index beb6676..b9c04bf 100644
--- a/src/xregex.c
+++ b/src/xregex.c
@@ -5,8 +5,8 @@
 #include "alloc.h"
 #include "config.h"
 #include "diag.h"
-#include "thread.h"
 #include "sanity.h"
+#include "thread.h"
 #include <errno.h>
 #include <pthread.h>
 #include <stdlib.h>
diff --git a/src/xspawn.c b/src/xspawn.c
index 80bafef..7fb63e0 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -187,7 +187,7 @@ fail:
 
 	// In case of a write error, the parent will still see that we exited
 	// unsuccessfully, but won't know why
-	(void) xwrite(pipefd[1], &error, sizeof(error));
+	(void)xwrite(pipefd[1], &error, sizeof(error));
 
 	xclose(pipefd[1]);
 	_Exit(127);
diff --git a/src/xtime.c b/src/xtime.c
index 79dafad..e90bdb1 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -81,7 +81,7 @@ static int safe_add(int *value, int delta) {
 
 static int floor_div(int n, int d) {
 	int a = n < 0;
-	return (n + a)/d - a;
+	return (n + a) / d - a;
 }
 
 static int wrap(int *value, int max, int *next) {
@@ -93,7 +93,7 @@ static int wrap(int *value, int max, int *next) {
 static int month_length(int year, int month) {
 	static const int month_lengths[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 	int ret = month_lengths[month];
-	if (month == 1 && year%4 == 0 && (year%100 != 0 || (year + 300)%400 == 0)) {
+	if (month == 1 && year % 4 == 0 && (year % 100 != 0 || (year + 300) % 400 == 0)) {
 		++ret;
 	}
 	return ret;
@@ -156,13 +156,13 @@ int xtimegm(struct tm *tm, time_t *timep) {
 		leap_days = floor_div(tm->tm_year + 3, 4) - floor_div(tm->tm_year + 99, 100) + floor_div(tm->tm_year + 299, 400) - 17;
 	}
 
-	long long epoch_days = 365LL*(tm->tm_year - 70) + leap_days + tm->tm_yday;
-	tm->tm_wday = (epoch_days + 4)%7;
+	long long epoch_days = 365LL * (tm->tm_year - 70) + leap_days + tm->tm_yday;
+	tm->tm_wday = (epoch_days + 4) % 7;
 	if (tm->tm_wday < 0) {
 		tm->tm_wday += 7;
 	}
 
-	long long epoch_time = tm->tm_sec + 60*(tm->tm_min + 60*(tm->tm_hour + 24*epoch_days));
+	long long epoch_time = tm->tm_sec + 60 * (tm->tm_min + 60 * (tm->tm_hour + 24 * epoch_days));
 	*timep = (time_t)epoch_time;
 	if ((long long)*timep != epoch_time) {
 		goto overflow;
@@ -296,7 +296,7 @@ end:
 			goto error;
 		}
 
-		int offset = 60*tz_hour + tz_min;
+		int offset = 60 * tz_hour + tz_min;
 		if (tz_negative) {
 			result->tv_sec -= offset;
 		} else {
diff --git a/tests/bfstd.c b/tests/bfstd.c
index 83964e5..33b3792 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -7,8 +7,8 @@
 #include <errno.h>
 #include <langinfo.h>
 #include <locale.h>
-#include <stdio.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/tests/mksock.c b/tests/mksock.c
index 42ef322..7023b4f 100644
--- a/tests/mksock.c
+++ b/tests/mksock.c
@@ -9,8 +9,8 @@
 #include "../src/bfstd.h"
 #include <errno.h>
 #include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>
diff --git a/tests/trie.c b/tests/trie.c
index 6ea94a2..656fd85 100644
--- a/tests/trie.c
+++ b/tests/trie.c
@@ -120,11 +120,11 @@ int main(void) {
 	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
 	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
-	memset(longstr + longsize/2, 0xAB, longsize/2);
+	memset(longstr + longsize / 2, 0xAB, longsize / 2);
 	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
 	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
-	memset(longstr, 0xAA, longsize/2);
+	memset(longstr, 0xAA, longsize / 2);
 	bfs_verify(!trie_find_mem(&trie, longstr, longsize));
 	bfs_verify(trie_insert_mem(&trie, longstr, longsize));
 
diff --git a/tests/xtimegm.c b/tests/xtimegm.c
index b2479b7..973b2eb 100644
--- a/tests/xtimegm.c
+++ b/tests/xtimegm.c
@@ -42,9 +42,9 @@ static bool tm_equal(const struct tm *tma, const struct tm *tmb) {
 
 static void tm_print(FILE *file, const struct tm *tm) {
 	fprintf(file, "Y%d M%d D%d  h%d m%d s%d  wd%d yd%d%s\n",
-	        tm->tm_year, tm->tm_mon, tm->tm_mday,
-	        tm->tm_hour, tm->tm_min, tm->tm_sec,
-	        tm->tm_wday, tm->tm_yday,
+		tm->tm_year, tm->tm_mon, tm->tm_mday,
+		tm->tm_hour, tm->tm_min, tm->tm_sec,
+		tm->tm_wday, tm->tm_yday,
 		tm->tm_isdst ? (tm->tm_isdst < 0 ? " (DST?)" : " (DST)") : "");
 }
 
-- 
cgit v1.2.3


From 026e8fbd248561396752552efa3cc04e0ac832b7 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 9 Nov 2023 12:59:20 -0500
Subject: config: s/BFS_FORMATTER/attr_format/

---
 src/bar.c     |  2 +-
 src/color.c   |  4 ++--
 src/color.h   |  4 ++--
 src/config.h  |  4 ++--
 src/diag.h    | 14 +++++++-------
 src/dstring.h |  8 ++++----
 src/eval.c    |  2 +-
 src/exec.c    |  2 +-
 src/opt.c     |  4 ++--
 src/parse.c   | 14 +++++++-------
 10 files changed, 29 insertions(+), 29 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/bar.c b/src/bar.c
index 57cc4dd..2e50dbe 100644
--- a/src/bar.c
+++ b/src/bar.c
@@ -127,7 +127,7 @@ static void reset_before_death_by(int sig) {
 }
 
 /** printf() to the status bar with a single write(). */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static int bfs_bar_printf(struct bfs_bar *bar, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
diff --git a/src/color.c b/src/color.c
index fbb5edf..7644ca3 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1105,7 +1105,7 @@ static int print_link_target(CFILE *cfile, const struct BFTW *ftwbuf) {
 }
 
 /** Format some colored output to the buffer. */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static int cbuff(CFILE *cfile, const char *format, ...);
 
 /** Dump a parsed expression tree, for debugging. */
@@ -1177,7 +1177,7 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 	return 0;
 }
 
-BFS_FORMATTER(2, 0)
+attr_format(2, 0)
 static int cvbuff(CFILE *cfile, const char *format, va_list args) {
 	const struct colors *colors = cfile->colors;
 	int error = errno;
diff --git a/src/color.h b/src/color.h
index b118f77..8a81573 100644
--- a/src/color.h
+++ b/src/color.h
@@ -100,13 +100,13 @@ int cfclose(CFILE *cfile);
  * @return
  *         0 on success, -1 on failure.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 int cfprintf(CFILE *cfile, const char *format, ...);
 
 /**
  * cfprintf() variant that takes a va_list.
  */
-BFS_FORMATTER(2, 0)
+attr_format(2, 0)
 int cvfprintf(CFILE *cfile, const char *format, va_list args);
 
 #endif // BFS_COLOR_H
diff --git a/src/config.h b/src/config.h
index e11941a..f19677c 100644
--- a/src/config.h
+++ b/src/config.h
@@ -188,9 +188,9 @@
  * Adds compiler warnings for bad printf()-style function calls, if supported.
  */
 #if __has_attribute(format)
-#  define BFS_FORMATTER(fmt, args) __attribute__((format(printf, fmt, args)))
+#  define attr_format(fmt, args) __attribute__((format(printf, fmt, args)))
 #else
-#  define BFS_FORMATTER(fmt, args)
+#  define attr_format(fmt, args)
 #endif
 
 /**
diff --git a/src/diag.h b/src/diag.h
index 838a794..8c7ed57 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -44,7 +44,7 @@ struct bfs_loc {
 /**
  * Print a message to standard error and abort.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...);
 
 /**
@@ -121,7 +121,7 @@ void bfs_perror(const struct bfs_ctx *ctx, const char *str);
 /**
  * Shorthand for printing error messages.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -129,7 +129,7 @@ void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a warning was printed.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -137,25 +137,25 @@ bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a debug message was printed.
  */
-BFS_FORMATTER(3, 4)
+attr_format(3, 4)
 bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...);
 
 /**
  * bfs_error() variant that takes a va_list.
  */
-BFS_FORMATTER(2, 0)
+attr_format(2, 0)
 void bfs_verror(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_warning() variant that takes a va_list.
  */
-BFS_FORMATTER(2, 0)
+attr_format(2, 0)
 bool bfs_vwarning(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_debug() variant that takes a va_list.
  */
-BFS_FORMATTER(3, 0)
+attr_format(3, 0)
 bool bfs_vdebug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, va_list args);
 
 /**
diff --git a/src/dstring.h b/src/dstring.h
index 6496a4f..fd98df8 100644
--- a/src/dstring.h
+++ b/src/dstring.h
@@ -230,7 +230,7 @@ int dstrxcpy(dchar **dest, const char *str, size_t len);
  * @return
  *         The created string, or NULL on failure.
  */
-BFS_FORMATTER(1, 2)
+attr_format(1, 2)
 char *dstrprintf(const char *format, ...);
 
 /**
@@ -243,7 +243,7 @@ char *dstrprintf(const char *format, ...);
  * @return
  *         The created string, or NULL on failure.
  */
-BFS_FORMATTER(1, 0)
+attr_format(1, 0)
 char *dstrvprintf(const char *format, va_list args);
 
 /**
@@ -258,7 +258,7 @@ char *dstrvprintf(const char *format, va_list args);
  * @return
  *         0 on success, -1 on failure.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 int dstrcatf(dchar **str, const char *format, ...);
 
 /**
@@ -273,7 +273,7 @@ int dstrcatf(dchar **str, const char *format, ...);
  * @return
  *         0 on success, -1 on failure.
  */
-BFS_FORMATTER(2, 0)
+attr_format(2, 0)
 int dstrvcatf(dchar **str, const char *format, va_list args);
 
 /**
diff --git a/src/eval.c b/src/eval.c
index b511eba..eb4a0ca 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -58,7 +58,7 @@ struct bfs_eval {
 /**
  * Print an error message.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static void eval_error(struct bfs_eval *state, const char *format, ...) {
 	// By POSIX, any errors should be accompanied by a non-zero exit status
 	*state->ret = EXIT_FAILURE;
diff --git a/src/exec.c b/src/exec.c
index f0730d2..ba82439 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -22,7 +22,7 @@
 #include <unistd.h>
 
 /** Print some debugging info. */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static void bfs_exec_debug(const struct bfs_exec *execbuf, const char *format, ...) {
 	const struct bfs_ctx *ctx = execbuf->ctx;
 
diff --git a/src/opt.c b/src/opt.c
index 77c2798..5da73d8 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -305,7 +305,7 @@ struct opt_state {
 };
 
 /** Log an optimization. */
-BFS_FORMATTER(3, 4)
+attr_format(3, 4)
 static bool opt_debug(const struct opt_state *state, int level, const char *format, ...) {
 	bfs_assert(state->ctx->optlevel >= level);
 
@@ -321,7 +321,7 @@ static bool opt_debug(const struct opt_state *state, int level, const char *form
 }
 
 /** Warn about an expression. */
-BFS_FORMATTER(3, 4)
+attr_format(3, 4)
 static void opt_warning(const struct opt_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	if (bfs_expr_warning(state->ctx, expr)) {
 		va_list args;
diff --git a/src/parse.c b/src/parse.c
index d21ab40..d3938fc 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -247,7 +247,7 @@ static void highlight_args(const struct bfs_ctx *ctx, char **argv, size_t argc,
 /**
  * Print an error message during parsing.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static void parse_error(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -267,7 +267,7 @@ static void parse_error(const struct parser_state *state, const char *format, ..
 /**
  * Print an error about some command line arguments.
  */
-BFS_FORMATTER(4, 5)
+attr_format(4, 5)
 static void parse_argv_error(const struct parser_state *state, char **argv, size_t argc, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -287,7 +287,7 @@ static void parse_argv_error(const struct parser_state *state, char **argv, size
 /**
  * Print an error about conflicting command line arguments.
  */
-BFS_FORMATTER(6, 7)
+attr_format(6, 7)
 static void parse_conflict_error(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -308,7 +308,7 @@ static void parse_conflict_error(const struct parser_state *state, char **argv1,
 /**
  * Print an error about an expression.
  */
-BFS_FORMATTER(3, 4)
+attr_format(3, 4)
 static void parse_expr_error(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -325,7 +325,7 @@ static void parse_expr_error(const struct parser_state *state, const struct bfs_
 /**
  * Print a warning message during parsing.
  */
-BFS_FORMATTER(2, 3)
+attr_format(2, 3)
 static bool parse_warning(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -348,7 +348,7 @@ static bool parse_warning(const struct parser_state *state, const char *format,
 /**
  * Print a warning about conflicting command line arguments.
  */
-BFS_FORMATTER(6, 7)
+attr_format(6, 7)
 static bool parse_conflict_warning(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -372,7 +372,7 @@ static bool parse_conflict_warning(const struct parser_state *state, char **argv
 /**
  * Print a warning about an expression.
  */
-BFS_FORMATTER(3, 4)
+attr_format(3, 4)
 static bool parse_expr_warning(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
-- 
cgit v1.2.3


From 5b38f658ee42bef05cecb6cadec65b25d9e94993 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 16 Nov 2023 12:25:09 -0500
Subject: config: New variadic attr(...) macro

---
 src/alloc.c   |  2 +-
 src/alloc.h   | 10 ++++----
 src/bar.c     |  2 +-
 src/color.c   |  4 ++--
 src/color.h   |  4 ++--
 src/config.h  | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/diag.h    | 37 ++++++++++++------------------
 src/dstring.h | 18 +++++++--------
 src/eval.c    |  2 +-
 src/exec.c    |  2 +-
 src/fsade.c   |  6 ++---
 src/ioq.c     |  4 ++--
 src/mtab.c    |  2 +-
 src/opt.c     |  4 ++--
 src/parse.c   | 14 +++++------
 src/trie.c    |  2 +-
 src/xspawn.c  |  2 +-
 17 files changed, 127 insertions(+), 62 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/alloc.c b/src/alloc.c
index 467f0f0..b65d0c5 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -176,7 +176,7 @@ void arena_init(struct arena *arena, size_t align, size_t size) {
 }
 
 /** Allocate a new slab. */
-attr_cold
+attr(cold)
 static int slab_alloc(struct arena *arena) {
 	// Make the initial allocation size ~4K
 	size_t size = 4096;
diff --git a/src/alloc.h b/src/alloc.h
index 7132470..f21ddb9 100644
--- a/src/alloc.h
+++ b/src/alloc.h
@@ -114,8 +114,7 @@ static inline size_t flex_size(size_t align, size_t min, size_t offset, size_t s
  * @return
  *         The allocated memory, or NULL on failure.
  */
-attr_malloc(free, 1)
-attr_aligned_alloc(1, 2)
+attr(malloc(free, 1), aligned_alloc(1, 2))
 void *alloc(size_t align, size_t size);
 
 /**
@@ -128,8 +127,7 @@ void *alloc(size_t align, size_t size);
  * @return
  *         The allocated memory, or NULL on failure.
  */
-attr_malloc(free, 1)
-attr_aligned_alloc(1, 2)
+attr(malloc(free, 1), aligned_alloc(1, 2))
 void *zalloc(size_t align, size_t size);
 
 /** Allocate memory for the given type. */
@@ -252,7 +250,7 @@ void arena_free(struct arena *arena, void *ptr);
 /**
  * Allocate an object out of the arena.
  */
-attr_malloc(arena_free, 2)
+attr(malloc(arena_free, 2))
 void *arena_alloc(struct arena *arena);
 
 /**
@@ -334,7 +332,7 @@ void varena_free(struct varena *varena, void *ptr, size_t count);
  * @return
  *         The allocated struct, or NULL on failure.
  */
-attr_malloc(varena_free, 2)
+attr(malloc(varena_free, 2))
 void *varena_alloc(struct varena *varena, size_t count);
 
 /**
diff --git a/src/bar.c b/src/bar.c
index 2e50dbe..babadc3 100644
--- a/src/bar.c
+++ b/src/bar.c
@@ -127,7 +127,7 @@ static void reset_before_death_by(int sig) {
 }
 
 /** printf() to the status bar with a single write(). */
-attr_format(2, 3)
+attr(format(2, 3))
 static int bfs_bar_printf(struct bfs_bar *bar, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
diff --git a/src/color.c b/src/color.c
index 05ba1a3..4c2c8ca 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1105,7 +1105,7 @@ static int print_link_target(CFILE *cfile, const struct BFTW *ftwbuf) {
 }
 
 /** Format some colored output to the buffer. */
-attr_format(2, 3)
+attr(format(2, 3))
 static int cbuff(CFILE *cfile, const char *format, ...);
 
 /** Dump a parsed expression tree, for debugging. */
@@ -1177,7 +1177,7 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 	return 0;
 }
 
-attr_format(2, 0)
+attr(format(2, 0))
 static int cvbuff(CFILE *cfile, const char *format, va_list args) {
 	const struct colors *colors = cfile->colors;
 	int error = errno;
diff --git a/src/color.h b/src/color.h
index 8a81573..81f0e2a 100644
--- a/src/color.h
+++ b/src/color.h
@@ -100,13 +100,13 @@ int cfclose(CFILE *cfile);
  * @return
  *         0 on success, -1 on failure.
  */
-attr_format(2, 3)
+attr(format(2, 3))
 int cfprintf(CFILE *cfile, const char *format, ...);
 
 /**
  * cfprintf() variant that takes a va_list.
  */
-attr_format(2, 0)
+attr(format(2, 0))
 int cvfprintf(CFILE *cfile, const char *format, va_list args);
 
 #endif // BFS_COLOR_H
diff --git a/src/config.h b/src/config.h
index 9f95674..aa03552 100644
--- a/src/config.h
+++ b/src/config.h
@@ -301,4 +301,78 @@ typedef long double max_align_t;
 #  define attr_target_clones(...)
 #endif
 
+/**
+ * Shorthand for multiple attributes at once. attr(a, b(c), d) is equivalent to
+ *
+ *     attr_a
+ *     attr_b(c)
+ *     attr_d
+ */
+#define attr(...) \
+	attr__(attr_##__VA_ARGS__, none, none, none, none, none, none, none, none, none)
+
+/**
+ * attr() helper.  For exposition, pretend we support only 2 args, instead of 9.
+ * There are a few cases:
+ *
+ *     attr()
+ *         => attr__(attr_, none, none)
+ *         => attr_                =>
+ *            attr_none            =>
+ *            attr_too_many_none() =>
+ *
+ *     attr(a)
+ *         => attr__(attr_a, none, none)
+ *         => attr_a               => __attribute__((a))
+ *            attr_none            =>
+ *            attr_too_many_none() =>
+ *
+ *     attr(a, b(c))
+ *         => attr__(attr_a, b(c), none, none)
+ *         => attr_a                   => __attribute__((a))
+ *            attr_b(c)                => __attribute__((b(c)))
+ *            attr_too_many_none(none) =>
+ *
+ *     attr(a, b(c), d)
+ *         => attr__(attr_a, b(c), d, none, none)
+ *         => attr_a                      => __attribute__((a))
+ *            attr_b(c)                   => __attribute__((b(c)))
+ *            attr_too_many_d(none, none) => error
+ *
+ * Some attribute names are the same as standard library functions, e.g. printf.
+ * Standard libraries are permitted to define these functions as macros, like
+ *
+ *     #define printf(...) __builtin_printf(__VA_ARGS__)
+ *
+ * The token paste in
+ *
+ *     #define attr(...) attr__(attr_##__VA_ARGS__, none, none)
+ *
+ * is necessary to prevent macro expansion before evaluating attr__().
+ * Otherwise, we could get
+ *
+ *     attr(printf(1, 2))
+ *         => attr__(__builtin_printf(1, 2), none, none)
+ *         => attr____builtin_printf(1, 2)
+ *         => error
+ */
+#define attr__(a1, a2, a3, a4, a5, a6, a7, a8, a9, none, ...) \
+	a1 \
+	attr_##a2 \
+	attr_##a3 \
+	attr_##a4 \
+	attr_##a5 \
+	attr_##a6 \
+	attr_##a7 \
+	attr_##a8 \
+	attr_##a9 \
+	attr_too_many_##none(__VA_ARGS__)
+
+// Ignore `attr_none` from expanding 1-9 argument attr(a1, a2, ...)
+#define attr_none
+// Ignore `attr_` from expanding 0-argument attr()
+#define attr_
+// Only trigger an error on more than 9 arguments
+#define attr_too_many_none(...)
+
 #endif // BFS_CONFIG_H
diff --git a/src/diag.h b/src/diag.h
index 981419e..aa6a44f 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -44,8 +44,7 @@ struct bfs_loc {
 /**
  * Print a message to standard error and abort.
  */
-attr_cold
-attr_format(2, 3)
+attr(cold, format(2, 3))
 noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...);
 
 /**
@@ -117,14 +116,13 @@ const char *debug_flag_name(enum debug_flags flag);
 /**
  * Like perror(), but decorated like bfs_error().
  */
-attr_cold
+attr(cold)
 void bfs_perror(const struct bfs_ctx *ctx, const char *str);
 
 /**
  * Shorthand for printing error messages.
  */
-attr_cold
-attr_format(2, 3)
+attr(cold, format(2, 3))
 void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -132,8 +130,7 @@ void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a warning was printed.
  */
-attr_cold
-attr_format(2, 3)
+attr(cold, format(2, 3))
 bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -141,71 +138,67 @@ bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a debug message was printed.
  */
-attr_cold
-attr_format(3, 4)
+attr(cold, format(3, 4))
 bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...);
 
 /**
  * bfs_error() variant that takes a va_list.
  */
-attr_cold
-attr_format(2, 0)
+attr(cold, format(2, 0))
 void bfs_verror(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_warning() variant that takes a va_list.
  */
-attr_cold
-attr_format(2, 0)
+attr(cold, format(2, 0))
 bool bfs_vwarning(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_debug() variant that takes a va_list.
  */
-attr_cold
-attr_format(3, 0)
+attr(cold, format(3, 0))
 bool bfs_vdebug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, va_list args);
 
 /**
  * Print the error message prefix.
  */
-attr_cold
+attr(cold)
 void bfs_error_prefix(const struct bfs_ctx *ctx);
 
 /**
  * Print the warning message prefix.
  */
-attr_cold
+attr(cold)
 bool bfs_warning_prefix(const struct bfs_ctx *ctx);
 
 /**
  * Print the debug message prefix.
  */
-attr_cold
+attr(cold)
 bool bfs_debug_prefix(const struct bfs_ctx *ctx, enum debug_flags flag);
 
 /**
  * Highlight parts of the command line in an error message.
  */
-attr_cold
+attr(cold)
 void bfs_argv_error(const struct bfs_ctx *ctx, const bool args[]);
 
 /**
  * Highlight parts of an expression in an error message.
  */
-attr_cold
+attr(cold)
 void bfs_expr_error(const struct bfs_ctx *ctx, const struct bfs_expr *expr);
 
 /**
  * Highlight parts of the command line in a warning message.
  */
-attr_cold
+attr(cold)
 bool bfs_argv_warning(const struct bfs_ctx *ctx, const bool args[]);
 
 /**
  * Highlight parts of an expression in a warning message.
  */
-attr_cold
+attr(cold)
 bool bfs_expr_warning(const struct bfs_ctx *ctx, const struct bfs_expr *expr);
 
 #endif // BFS_DIAG_H
diff --git a/src/dstring.h b/src/dstring.h
index 2a94438..1be1185 100644
--- a/src/dstring.h
+++ b/src/dstring.h
@@ -41,7 +41,7 @@ void dstrfree(dchar *dstr);
  * @param cap
  *         The initial capacity of the string.
  */
-attr_malloc(dstrfree, 1)
+attr(malloc(dstrfree, 1))
 dchar *dstralloc(size_t cap);
 
 /**
@@ -50,7 +50,7 @@ dchar *dstralloc(size_t cap);
  * @param str
  *         The NUL-terminated string to copy.
  */
-attr_malloc(dstrfree, 1)
+attr(malloc(dstrfree, 1))
 dchar *dstrdup(const char *str);
 
 /**
@@ -61,7 +61,7 @@ dchar *dstrdup(const char *str);
  * @param n
  *         The maximum number of characters to copy from str.
  */
-attr_malloc(dstrfree, 1)
+attr(malloc(dstrfree, 1))
 dchar *dstrndup(const char *str, size_t n);
 
 /**
@@ -70,7 +70,7 @@ dchar *dstrndup(const char *str, size_t n);
  * @param dstr
  *         The dynamic string to copy.
  */
-attr_malloc(dstrfree, 1)
+attr(malloc(dstrfree, 1))
 dchar *dstrddup(const dchar *dstr);
 
 /**
@@ -81,7 +81,7 @@ dchar *dstrddup(const dchar *dstr);
  * @param len
  *         The length of the string, which may include internal NUL bytes.
  */
-attr_malloc(dstrfree, 1)
+attr(malloc(dstrfree, 1))
 dchar *dstrxdup(const char *str, size_t len);
 
 /**
@@ -243,7 +243,7 @@ int dstrxcpy(dchar **dest, const char *str, size_t len);
  * @return
  *         The created string, or NULL on failure.
  */
-attr_format(1, 2)
+attr(format(1, 2))
 char *dstrprintf(const char *format, ...);
 
 /**
@@ -256,7 +256,7 @@ char *dstrprintf(const char *format, ...);
  * @return
  *         The created string, or NULL on failure.
  */
-attr_format(1, 0)
+attr(format(1, 0))
 char *dstrvprintf(const char *format, va_list args);
 
 /**
@@ -271,7 +271,7 @@ char *dstrvprintf(const char *format, va_list args);
  * @return
  *         0 on success, -1 on failure.
  */
-attr_format(2, 3)
+attr(format(2, 3))
 int dstrcatf(dchar **str, const char *format, ...);
 
 /**
@@ -286,7 +286,7 @@ int dstrcatf(dchar **str, const char *format, ...);
  * @return
  *         0 on success, -1 on failure.
  */
-attr_format(2, 0)
+attr(format(2, 0))
 int dstrvcatf(dchar **str, const char *format, va_list args);
 
 /**
diff --git a/src/eval.c b/src/eval.c
index a990fd4..859ad7e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -57,7 +57,7 @@ struct bfs_eval {
 /**
  * Print an error message.
  */
-attr_format(2, 3)
+attr(format(2, 3))
 static void eval_error(struct bfs_eval *state, const char *format, ...) {
 	// By POSIX, any errors should be accompanied by a non-zero exit status
 	*state->ret = EXIT_FAILURE;
diff --git a/src/exec.c b/src/exec.c
index 90b3598..ba2fec8 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -22,7 +22,7 @@
 #include <unistd.h>
 
 /** Print some debugging info. */
-attr_format(2, 3)
+attr(format(2, 3))
 static void bfs_exec_debug(const struct bfs_exec *execbuf, const char *format, ...) {
 	const struct bfs_ctx *ctx = execbuf->ctx;
 
diff --git a/src/fsade.c b/src/fsade.c
index 4d22d99..a48eeb0 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -32,7 +32,7 @@
  * Many of the APIs used here don't have *at() variants, but we can try to
  * emulate something similar if /proc/self/fd is available.
  */
-attr_maybe_unused
+attr(maybe_unused)
 static const char *fake_at(const struct BFTW *ftwbuf) {
 	static atomic int proc_works = -1;
 
@@ -66,7 +66,7 @@ fail:
 	return ftwbuf->path;
 }
 
-attr_maybe_unused
+attr(maybe_unused)
 static void free_fake_at(const struct BFTW *ftwbuf, const char *path) {
 	if (path != ftwbuf->path) {
 		dstrfree((dchar *)path);
@@ -76,7 +76,7 @@ static void free_fake_at(const struct BFTW *ftwbuf, const char *path) {
 /**
  * Check if an error was caused by the absence of support or data for a feature.
  */
-attr_maybe_unused
+attr(maybe_unused)
 static bool is_absence_error(int error) {
 	// If the OS doesn't support the feature, it's obviously not enabled for
 	// any files
diff --git a/src/ioq.c b/src/ioq.c
index bd8d111..2739338 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -273,7 +273,7 @@ static struct ioq_monitor *ioq_slot_monitor(struct ioqq *ioqq, ioq_slot *slot) {
 }
 
 /** Atomically wait for a slot to change. */
-attr_noinline
+attr(noinline)
 static uintptr_t ioq_slot_wait(struct ioqq *ioqq, ioq_slot *slot, uintptr_t value) {
 	struct ioq_monitor *monitor = ioq_slot_monitor(ioqq, slot);
 	mutex_lock(&monitor->mutex);
@@ -303,7 +303,7 @@ done:
 }
 
 /** Wake up any threads waiting on a slot. */
-attr_noinline
+attr(noinline)
 static void ioq_slot_wake(struct ioqq *ioqq, ioq_slot *slot) {
 	struct ioq_monitor *monitor = ioq_slot_monitor(ioqq, slot);
 
diff --git a/src/mtab.c b/src/mtab.c
index 082150c..cc726a2 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -61,7 +61,7 @@ struct bfs_mtab {
 /**
  * Add an entry to the mount table.
  */
-attr_maybe_unused
+attr(maybe_unused)
 static int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *type) {
 	struct bfs_mount *mount = RESERVE(struct bfs_mount, &mtab->mounts, &mtab->nmounts);
 	if (!mount) {
diff --git a/src/opt.c b/src/opt.c
index 5da73d8..3ee5e81 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -305,7 +305,7 @@ struct opt_state {
 };
 
 /** Log an optimization. */
-attr_format(3, 4)
+attr(format(3, 4))
 static bool opt_debug(const struct opt_state *state, int level, const char *format, ...) {
 	bfs_assert(state->ctx->optlevel >= level);
 
@@ -321,7 +321,7 @@ static bool opt_debug(const struct opt_state *state, int level, const char *form
 }
 
 /** Warn about an expression. */
-attr_format(3, 4)
+attr(format(3, 4))
 static void opt_warning(const struct opt_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	if (bfs_expr_warning(state->ctx, expr)) {
 		va_list args;
diff --git a/src/parse.c b/src/parse.c
index 778fc68..35d22fb 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -246,7 +246,7 @@ static void highlight_args(const struct bfs_ctx *ctx, char **argv, size_t argc,
 /**
  * Print an error message during parsing.
  */
-attr_format(2, 3)
+attr(format(2, 3))
 static void parse_error(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -266,7 +266,7 @@ static void parse_error(const struct parser_state *state, const char *format, ..
 /**
  * Print an error about some command line arguments.
  */
-attr_format(4, 5)
+attr(format(4, 5))
 static void parse_argv_error(const struct parser_state *state, char **argv, size_t argc, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -286,7 +286,7 @@ static void parse_argv_error(const struct parser_state *state, char **argv, size
 /**
  * Print an error about conflicting command line arguments.
  */
-attr_format(6, 7)
+attr(format(6, 7))
 static void parse_conflict_error(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -307,7 +307,7 @@ static void parse_conflict_error(const struct parser_state *state, char **argv1,
 /**
  * Print an error about an expression.
  */
-attr_format(3, 4)
+attr(format(3, 4))
 static void parse_expr_error(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -324,7 +324,7 @@ static void parse_expr_error(const struct parser_state *state, const struct bfs_
 /**
  * Print a warning message during parsing.
  */
-attr_format(2, 3)
+attr(format(2, 3))
 static bool parse_warning(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -347,7 +347,7 @@ static bool parse_warning(const struct parser_state *state, const char *format,
 /**
  * Print a warning about conflicting command line arguments.
  */
-attr_format(6, 7)
+attr(format(6, 7))
 static bool parse_conflict_warning(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -371,7 +371,7 @@ static bool parse_conflict_warning(const struct parser_state *state, char **argv
 /**
  * Print a warning about an expression.
  */
-attr_format(3, 4)
+attr(format(3, 4))
 static bool parse_expr_warning(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
diff --git a/src/trie.c b/src/trie.c
index cf55cee..bd5300d 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -95,7 +95,7 @@
 bfs_static_assert(CHAR_WIDTH == 8);
 
 #if __i386__ || __x86_64__
-#  define trie_clones attr_target_clones("popcnt", "default")
+#  define trie_clones attr(target_clones("popcnt", "default"))
 #else
 #  define trie_clones
 #endif
diff --git a/src/xspawn.c b/src/xspawn.c
index 03287c3..40115a1 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -83,7 +83,7 @@ int bfs_spawn_destroy(struct bfs_spawn *ctx) {
 
 #if _POSIX_SPAWN > 0
 /** Set some posix_spawnattr flags. */
-attr_maybe_unused
+attr(maybe_unused)
 static int bfs_spawn_addflags(struct bfs_spawn *ctx, short flags) {
 	short prev;
 	errno = posix_spawnattr_getflags(&ctx->attr, &prev);
-- 
cgit v1.2.3


From a85fc263a89fb89bc8b2a8166747660a177b1773 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 22 Nov 2023 09:33:49 -0500
Subject: config: s/attr_format/attr_printf/

---
 src/bar.c     |  2 +-
 src/color.c   |  4 ++--
 src/color.h   |  4 ++--
 src/config.h  |  4 ++--
 src/diag.h    | 14 +++++++-------
 src/dstring.h |  8 ++++----
 src/eval.c    |  2 +-
 src/exec.c    |  2 +-
 src/opt.c     |  4 ++--
 src/parse.c   | 14 +++++++-------
 10 files changed, 29 insertions(+), 29 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/bar.c b/src/bar.c
index babadc3..8ab4112 100644
--- a/src/bar.c
+++ b/src/bar.c
@@ -127,7 +127,7 @@ static void reset_before_death_by(int sig) {
 }
 
 /** printf() to the status bar with a single write(). */
-attr(format(2, 3))
+attr(printf(2, 3))
 static int bfs_bar_printf(struct bfs_bar *bar, const char *format, ...) {
 	va_list args;
 	va_start(args, format);
diff --git a/src/color.c b/src/color.c
index 4c2c8ca..5247cbf 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1105,7 +1105,7 @@ static int print_link_target(CFILE *cfile, const struct BFTW *ftwbuf) {
 }
 
 /** Format some colored output to the buffer. */
-attr(format(2, 3))
+attr(printf(2, 3))
 static int cbuff(CFILE *cfile, const char *format, ...);
 
 /** Dump a parsed expression tree, for debugging. */
@@ -1177,7 +1177,7 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 	return 0;
 }
 
-attr(format(2, 0))
+attr(printf(2, 0))
 static int cvbuff(CFILE *cfile, const char *format, va_list args) {
 	const struct colors *colors = cfile->colors;
 	int error = errno;
diff --git a/src/color.h b/src/color.h
index 81f0e2a..760aa9d 100644
--- a/src/color.h
+++ b/src/color.h
@@ -100,13 +100,13 @@ int cfclose(CFILE *cfile);
  * @return
  *         0 on success, -1 on failure.
  */
-attr(format(2, 3))
+attr(printf(2, 3))
 int cfprintf(CFILE *cfile, const char *format, ...);
 
 /**
  * cfprintf() variant that takes a va_list.
  */
-attr(format(2, 0))
+attr(printf(2, 0))
 int cvfprintf(CFILE *cfile, const char *format, va_list args);
 
 #endif // BFS_COLOR_H
diff --git a/src/config.h b/src/config.h
index aa03552..46f1efe 100644
--- a/src/config.h
+++ b/src/config.h
@@ -240,9 +240,9 @@ typedef long double max_align_t;
  * Adds compiler warnings for bad printf()-style function calls, if supported.
  */
 #if __has_attribute(format)
-#  define attr_format(fmt, args) __attribute__((format(printf, fmt, args)))
+#  define attr_printf(fmt, args) __attribute__((format(printf, fmt, args)))
 #else
-#  define attr_format(fmt, args)
+#  define attr_printf(fmt, args)
 #endif
 
 /**
diff --git a/src/diag.h b/src/diag.h
index aa6a44f..791c065 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -44,7 +44,7 @@ struct bfs_loc {
 /**
  * Print a message to standard error and abort.
  */
-attr(cold, format(2, 3))
+attr(cold, printf(2, 3))
 noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...);
 
 /**
@@ -122,7 +122,7 @@ void bfs_perror(const struct bfs_ctx *ctx, const char *str);
 /**
  * Shorthand for printing error messages.
  */
-attr(cold, format(2, 3))
+attr(cold, printf(2, 3))
 void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -130,7 +130,7 @@ void bfs_error(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a warning was printed.
  */
-attr(cold, format(2, 3))
+attr(cold, printf(2, 3))
 bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
 
 /**
@@ -138,25 +138,25 @@ bool bfs_warning(const struct bfs_ctx *ctx, const char *format, ...);
  *
  * @return Whether a debug message was printed.
  */
-attr(cold, format(3, 4))
+attr(cold, printf(3, 4))
 bool bfs_debug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, ...);
 
 /**
  * bfs_error() variant that takes a va_list.
  */
-attr(cold, format(2, 0))
+attr(cold, printf(2, 0))
 void bfs_verror(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_warning() variant that takes a va_list.
  */
-attr(cold, format(2, 0))
+attr(cold, printf(2, 0))
 bool bfs_vwarning(const struct bfs_ctx *ctx, const char *format, va_list args);
 
 /**
  * bfs_debug() variant that takes a va_list.
  */
-attr(cold, format(3, 0))
+attr(cold, printf(3, 0))
 bool bfs_vdebug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *format, va_list args);
 
 /**
diff --git a/src/dstring.h b/src/dstring.h
index 1be1185..6006199 100644
--- a/src/dstring.h
+++ b/src/dstring.h
@@ -243,7 +243,7 @@ int dstrxcpy(dchar **dest, const char *str, size_t len);
  * @return
  *         The created string, or NULL on failure.
  */
-attr(format(1, 2))
+attr(printf(1, 2))
 char *dstrprintf(const char *format, ...);
 
 /**
@@ -256,7 +256,7 @@ char *dstrprintf(const char *format, ...);
  * @return
  *         The created string, or NULL on failure.
  */
-attr(format(1, 0))
+attr(printf(1, 0))
 char *dstrvprintf(const char *format, va_list args);
 
 /**
@@ -271,7 +271,7 @@ char *dstrvprintf(const char *format, va_list args);
  * @return
  *         0 on success, -1 on failure.
  */
-attr(format(2, 3))
+attr(printf(2, 3))
 int dstrcatf(dchar **str, const char *format, ...);
 
 /**
@@ -286,7 +286,7 @@ int dstrcatf(dchar **str, const char *format, ...);
  * @return
  *         0 on success, -1 on failure.
  */
-attr(format(2, 0))
+attr(printf(2, 0))
 int dstrvcatf(dchar **str, const char *format, va_list args);
 
 /**
diff --git a/src/eval.c b/src/eval.c
index 859ad7e..372fcf5 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -57,7 +57,7 @@ struct bfs_eval {
 /**
  * Print an error message.
  */
-attr(format(2, 3))
+attr(printf(2, 3))
 static void eval_error(struct bfs_eval *state, const char *format, ...) {
 	// By POSIX, any errors should be accompanied by a non-zero exit status
 	*state->ret = EXIT_FAILURE;
diff --git a/src/exec.c b/src/exec.c
index ba2fec8..60bfd28 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -22,7 +22,7 @@
 #include <unistd.h>
 
 /** Print some debugging info. */
-attr(format(2, 3))
+attr(printf(2, 3))
 static void bfs_exec_debug(const struct bfs_exec *execbuf, const char *format, ...) {
 	const struct bfs_ctx *ctx = execbuf->ctx;
 
diff --git a/src/opt.c b/src/opt.c
index 3ee5e81..ddcd1ab 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -305,7 +305,7 @@ struct opt_state {
 };
 
 /** Log an optimization. */
-attr(format(3, 4))
+attr(printf(3, 4))
 static bool opt_debug(const struct opt_state *state, int level, const char *format, ...) {
 	bfs_assert(state->ctx->optlevel >= level);
 
@@ -321,7 +321,7 @@ static bool opt_debug(const struct opt_state *state, int level, const char *form
 }
 
 /** Warn about an expression. */
-attr(format(3, 4))
+attr(printf(3, 4))
 static void opt_warning(const struct opt_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	if (bfs_expr_warning(state->ctx, expr)) {
 		va_list args;
diff --git a/src/parse.c b/src/parse.c
index 35d22fb..8d9c3f0 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -246,7 +246,7 @@ static void highlight_args(const struct bfs_ctx *ctx, char **argv, size_t argc,
 /**
  * Print an error message during parsing.
  */
-attr(format(2, 3))
+attr(printf(2, 3))
 static void parse_error(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -266,7 +266,7 @@ static void parse_error(const struct parser_state *state, const char *format, ..
 /**
  * Print an error about some command line arguments.
  */
-attr(format(4, 5))
+attr(printf(4, 5))
 static void parse_argv_error(const struct parser_state *state, char **argv, size_t argc, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -286,7 +286,7 @@ static void parse_argv_error(const struct parser_state *state, char **argv, size
 /**
  * Print an error about conflicting command line arguments.
  */
-attr(format(6, 7))
+attr(printf(6, 7))
 static void parse_conflict_error(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -307,7 +307,7 @@ static void parse_conflict_error(const struct parser_state *state, char **argv1,
 /**
  * Print an error about an expression.
  */
-attr(format(3, 4))
+attr(printf(3, 4))
 static void parse_expr_error(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -324,7 +324,7 @@ static void parse_expr_error(const struct parser_state *state, const struct bfs_
 /**
  * Print a warning message during parsing.
  */
-attr(format(2, 3))
+attr(printf(2, 3))
 static bool parse_warning(const struct parser_state *state, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -347,7 +347,7 @@ static bool parse_warning(const struct parser_state *state, const char *format,
 /**
  * Print a warning about conflicting command line arguments.
  */
-attr(format(6, 7))
+attr(printf(6, 7))
 static bool parse_conflict_warning(const struct parser_state *state, char **argv1, size_t argc1, char **argv2, size_t argc2, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
@@ -371,7 +371,7 @@ static bool parse_conflict_warning(const struct parser_state *state, char **argv
 /**
  * Print a warning about an expression.
  */
-attr(format(3, 4))
+attr(printf(3, 4))
 static bool parse_expr_warning(const struct parser_state *state, const struct bfs_expr *expr, const char *format, ...) {
 	int error = errno;
 	const struct bfs_ctx *ctx = state->ctx;
-- 
cgit v1.2.3


From c60d93493f958cde1769a90058dac719ae1efa8c Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sat, 29 Jul 2023 14:44:26 -0400
Subject: opt: Use more standard terminology for data flow domains

---
 src/opt.c | 592 +++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 294 insertions(+), 298 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index ddcd1ab..a989670 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -6,14 +6,13 @@
  *
  * -O1: basic logical simplifications, like folding (-true -and -foo) to -foo.
  *
- * -O2: dead code elimination and data flow analysis.  struct opt_facts is used
+ * -O2: dead code elimination and data flow analysis.  struct df_domain is used
  * to record data flow facts that are true at various points of evaluation.
- * Specifically, struct opt_facts records the facts that must be true before an
- * expression is evaluated (state->facts), and those that must be true after the
- * expression is evaluated, given that it returns true (state->facts_when_true)
- * or false (state->facts_when_true).  Additionally, state->facts_when_impure
- * records the possible data flow facts before any expressions with side effects
- * are evaluated.
+ * Specifically, struct df_domain records the state before an expression is
+ * evaluated (opt->before), and after an expression returns true
+ * (opt->after_true) or false (opt->after_false).  Additionally, opt->impure
+ * records the possible state before any expression with side effects is
+ * evaluated.
  *
  * -O3: expression re-ordering to reduce expected cost.  In an expression like
  * (-foo -and -bar), if both -foo and -bar are pure (no side effects), they can
@@ -22,8 +21,8 @@
  * -bar is likely to return false.
  *
  * -O4/-Ofast: aggressive optimizations that may affect correctness in corner
- * cases.  The main effect is to use facts_when_impure to determine if any side-
- * effects are reachable at all, and skipping the traversal if not.
+ * cases.  The main effect is to use impure to determine if any side-effects are
+ * reachable at all, and skipping the traversal if not.
  */
 
 #include "opt.h"
@@ -46,16 +45,58 @@ static char *fake_and_arg = "-a";
 static char *fake_or_arg = "-o";
 static char *fake_not_arg = "!";
 
+/**
+ * The data flow domain for predicates.
+ */
+enum df_pred {
+	/** The bottom state (unreachable). */
+	PRED_BOTTOM = 0,
+	/** The predicate is known to be false. */
+	PRED_FALSE = 1 << false,
+	/** The predicate is known to be true. */
+	PRED_TRUE = 1 << true,
+	/** The top state (unknown). */
+	PRED_TOP = PRED_FALSE | PRED_TRUE,
+};
+
+/** Make a predicate known. */
+static void constrain_pred(enum df_pred *pred, bool value) {
+	*pred &= 1 << value;
+}
+
+/** Compute the join (union) of two predicates. */
+static void pred_join(enum df_pred *dest, enum df_pred src) {
+	*dest |= src;
+}
+
 /**
  * A contrained integer range.
  */
-struct range {
+struct df_range {
 	/** The (inclusive) minimum value. */
 	long long min;
 	/** The (inclusive) maximum value. */
 	long long max;
 };
 
+/** Initialize an empty range. */
+static void range_init_bottom(struct df_range *range) {
+	range->min = LLONG_MAX;
+	range->max = LLONG_MIN;
+}
+
+/** Check if a range is empty. */
+static bool range_is_bottom(const struct df_range *range) {
+	return range->min > range->max;
+}
+
+/** Initialize a full range. */
+static void range_init_top(struct df_range *range) {
+	// All ranges we currently track are non-negative
+	range->min = 0;
+	range->max = LLONG_MAX;
+}
+
 /** Compute the minimum of two values. */
 static long long min_value(long long a, long long b) {
 	if (a < b) {
@@ -75,17 +116,17 @@ static long long max_value(long long a, long long b) {
 }
 
 /** Constrain the minimum of a range. */
-static void constrain_min(struct range *range, long long value) {
+static void constrain_min(struct df_range *range, long long value) {
 	range->min = max_value(range->min, value);
 }
 
 /** Contrain the maximum of a range. */
-static void constrain_max(struct range *range, long long value) {
+static void constrain_max(struct df_range *range, long long value) {
 	range->max = min_value(range->max, value);
 }
 
 /** Remove a single value from a range. */
-static void range_remove(struct range *range, long long value) {
+static void range_remove(struct df_range *range, long long value) {
 	if (range->min == value) {
 		if (range->min == LLONG_MAX) {
 			range->max = LLONG_MIN;
@@ -104,20 +145,9 @@ static void range_remove(struct range *range, long long value) {
 }
 
 /** Compute the union of two ranges. */
-static void range_union(struct range *result, const struct range *lhs, const struct range *rhs) {
-	result->min = min_value(lhs->min, rhs->min);
-	result->max = max_value(lhs->max, rhs->max);
-}
-
-/** Check if a range contains no values. */
-static bool range_is_impossible(const struct range *range) {
-	return range->min > range->max;
-}
-
-/** Set a range to contain no values. */
-static void set_range_impossible(struct range *range) {
-	range->min = LLONG_MAX;
-	range->max = LLONG_MIN;
+static void range_join(struct df_range *dest, const struct df_range *src) {
+	dest->min = min_value(dest->min, src->min);
+	dest->max = max_value(dest->max, src->max);
 }
 
 /**
@@ -140,42 +170,6 @@ enum range_type {
 	RANGE_TYPES,
 };
 
-/**
- * A possibly-known value of a predicate.
- */
-enum known_pred {
-	/** The state is impossible to reach. */
-	PRED_IMPOSSIBLE = -2,
-	/** The value of the predicate is not known. */
-	PRED_UNKNOWN = -1,
-	/** The predicate is known to be false. */
-	PRED_FALSE = false,
-	/** The predicate is known to be true. */
-	PRED_TRUE = true,
-};
-
-/** Make a predicate known. */
-static void constrain_pred(enum known_pred *pred, bool value) {
-	if (*pred == PRED_UNKNOWN) {
-		*pred = value;
-	} else if (*pred == !value) {
-		*pred = PRED_IMPOSSIBLE;
-	}
-}
-
-/** Compute the union of two known predicates. */
-static enum known_pred pred_union(enum known_pred lhs, enum known_pred rhs) {
-	if (lhs == PRED_IMPOSSIBLE) {
-		return rhs;
-	} else if (rhs == PRED_IMPOSSIBLE) {
-		return lhs;
-	} else if (lhs == rhs) {
-		return lhs;
-	} else {
-		return PRED_UNKNOWN;
-	}
-}
-
 /**
  * Types of predicates we track.
  */
@@ -207,14 +201,14 @@ enum pred_type {
 };
 
 /**
- * Data flow facts about an evaluation point.
+ * The data flow analysis domain.
  */
-struct opt_facts {
-	/** The value ranges we track. */
-	struct range ranges[RANGE_TYPES];
-
+struct df_domain {
 	/** The predicates we track. */
-	enum known_pred preds[PRED_TYPES];
+	enum df_pred preds[PRED_TYPES];
+
+	/** The value ranges we track. */
+	struct df_range ranges[RANGE_TYPES];
 
 	/** Bitmask of possible file types. */
 	unsigned int types;
@@ -222,97 +216,101 @@ struct opt_facts {
 	unsigned int xtypes;
 };
 
-/** Initialize some data flow facts. */
-static void facts_init(struct opt_facts *facts) {
-	for (int i = 0; i < RANGE_TYPES; ++i) {
-		struct range *range = &facts->ranges[i];
-		range->min = 0; // All ranges we currently track are non-negative
-		range->max = LLONG_MAX;
-	}
-
+/** Set a data flow value to bottom. */
+static void df_init_bottom(struct df_domain *value) {
 	for (int i = 0; i < PRED_TYPES; ++i) {
-		facts->preds[i] = PRED_UNKNOWN;
+		value->preds[i] = PRED_BOTTOM;
 	}
 
-	facts->types = ~0;
-	facts->xtypes = ~0;
-}
-
-/** Compute the union of two fact sets. */
-static void facts_union(struct opt_facts *result, const struct opt_facts *lhs, const struct opt_facts *rhs) {
 	for (int i = 0; i < RANGE_TYPES; ++i) {
-		range_union(&result->ranges[i], &lhs->ranges[i], &rhs->ranges[i]);
+		range_init_bottom(&value->ranges[i]);
 	}
 
-	for (int i = 0; i < PRED_TYPES; ++i) {
-		result->preds[i] = pred_union(lhs->preds[i], rhs->preds[i]);
-	}
-
-	result->types = lhs->types | rhs->types;
-	result->xtypes = lhs->xtypes | rhs->xtypes;
+	value->types = 0;
+	value->xtypes = 0;
 }
 
 /** Determine whether a fact set is impossible. */
-static bool facts_are_impossible(const struct opt_facts *facts) {
+static bool df_is_bottom(const struct df_domain *value) {
 	for (int i = 0; i < RANGE_TYPES; ++i) {
-		if (range_is_impossible(&facts->ranges[i])) {
+		if (range_is_bottom(&value->ranges[i])) {
 			return true;
 		}
 	}
 
 	for (int i = 0; i < PRED_TYPES; ++i) {
-		if (facts->preds[i] == PRED_IMPOSSIBLE) {
+		if (value->preds[i] == PRED_BOTTOM) {
 			return true;
 		}
 	}
 
-	if (!facts->types || !facts->xtypes) {
+	if (!value->types || !value->xtypes) {
 		return true;
 	}
 
 	return false;
 }
 
-/** Set some facts to be impossible. */
-static void set_facts_impossible(struct opt_facts *facts) {
+/** Initialize some data flow value. */
+static void df_init_top(struct df_domain *value) {
+	for (int i = 0; i < PRED_TYPES; ++i) {
+		value->preds[i] = PRED_TOP;
+	}
+
 	for (int i = 0; i < RANGE_TYPES; ++i) {
-		set_range_impossible(&facts->ranges[i]);
+		range_init_top(&value->ranges[i]);
 	}
 
+	value->types = ~0;
+	value->xtypes = ~0;
+}
+
+/** Compute the union of two fact sets. */
+static void df_join(struct df_domain *dest, const struct df_domain *src) {
 	for (int i = 0; i < PRED_TYPES; ++i) {
-		facts->preds[i] = PRED_IMPOSSIBLE;
+		pred_join(&dest->preds[i], src->preds[i]);
 	}
 
-	facts->types = 0;
-	facts->xtypes = 0;
+	for (int i = 0; i < RANGE_TYPES; ++i) {
+		range_join(&dest->ranges[i], &src->ranges[i]);
+	}
+
+	dest->types |= src->types;
+	dest->xtypes |= src->xtypes;
 }
 
 /**
  * Optimizer state.
  */
-struct opt_state {
+struct bfs_opt {
 	/** The context we're optimizing. */
 	const struct bfs_ctx *ctx;
 
-	/** Data flow facts before this expression is evaluated. */
-	struct opt_facts facts;
-	/** Data flow facts after this expression returns true. */
-	struct opt_facts facts_when_true;
-	/** Data flow facts after this expression returns false. */
-	struct opt_facts facts_when_false;
-	/** Data flow facts before any side-effecting expressions are evaluated. */
-	struct opt_facts *facts_when_impure;
+	/** Data flow state before this expression is evaluated. */
+	struct df_domain before;
+	/** Data flow state after this expression returns true. */
+	struct df_domain after_true;
+	/** Data flow state after this expression returns false. */
+	struct df_domain after_false;
+	/** Data flow state before any side-effecting expressions are evaluated. */
+	struct df_domain *impure;
 };
 
+/** Constrain the value of a predicate. */
+static void opt_constrain_pred(struct bfs_opt *opt, enum pred_type type, bool value) {
+	constrain_pred(&opt->after_true.preds[type], value);
+	constrain_pred(&opt->after_false.preds[type], !value);
+}
+
 /** Log an optimization. */
 attr(printf(3, 4))
-static bool opt_debug(const struct opt_state *state, int level, const char *format, ...) {
-	bfs_assert(state->ctx->optlevel >= level);
+static bool opt_debug(const struct bfs_opt *opt, int level, const char *format, ...) {
+	bfs_assert(opt->ctx->optlevel >= level);
 
-	if (bfs_debug(state->ctx, DEBUG_OPT, "${cyn}-O%d${rs}: ", level)) {
+	if (bfs_debug(opt->ctx, DEBUG_OPT, "${cyn}-O%d${rs}: ", level)) {
 		va_list args;
 		va_start(args, format);
-		cvfprintf(state->ctx->cerr, format, args);
+		cvfprintf(opt->ctx->cerr, format, args);
 		va_end(args);
 		return true;
 	} else {
@@ -322,11 +320,11 @@ static bool opt_debug(const struct opt_state *state, int level, const char *form
 
 /** Warn about an expression. */
 attr(printf(3, 4))
-static void opt_warning(const struct opt_state *state, const struct bfs_expr *expr, const char *format, ...) {
-	if (bfs_expr_warning(state->ctx, expr)) {
+static void opt_warning(const struct bfs_opt *opt, const struct bfs_expr *expr, const char *format, ...) {
+	if (bfs_expr_warning(opt->ctx, expr)) {
 		va_list args;
 		va_start(args, format);
-		bfs_vwarning(state->ctx, format, args);
+		bfs_vwarning(opt->ctx, format, args);
 		va_end(args);
 	}
 }
@@ -365,15 +363,15 @@ static struct bfs_expr *negate_expr(struct bfs_expr *rhs, char **argv) {
 	return expr;
 }
 
-static struct bfs_expr *optimize_not_expr(const struct opt_state *state, struct bfs_expr *expr);
-static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct bfs_expr *expr);
-static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct bfs_expr *expr);
+static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
+static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
+static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
 
 /**
  * Apply De Morgan's laws.
  */
-static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr *expr, char **argv) {
-	bool debug = opt_debug(state, 1, "De Morgan's laws: %pe ", expr);
+static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *expr, char **argv) {
+	bool debug = opt_debug(opt, 1, "De Morgan's laws: %pe ", expr);
 
 	struct bfs_expr *parent = negate_expr(expr, argv);
 	if (!parent) {
@@ -403,14 +401,14 @@ static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr
 	}
 
 	if (debug) {
-		cfprintf(state->ctx->cerr, "<==> %pe\n", parent);
+		cfprintf(opt->ctx->cerr, "<==> %pe\n", parent);
 	}
 
 	if (expr->lhs->eval_fn == eval_not) {
-		expr->lhs = optimize_not_expr(state, expr->lhs);
+		expr->lhs = optimize_not_expr(opt, expr->lhs);
 	}
 	if (expr->rhs->eval_fn == eval_not) {
-		expr->rhs = optimize_not_expr(state, expr->rhs);
+		expr->rhs = optimize_not_expr(opt, expr->rhs);
 	}
 	if (!expr->lhs || !expr->rhs) {
 		bfs_expr_free(parent);
@@ -418,9 +416,9 @@ static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr
 	}
 
 	if (expr->eval_fn == eval_and) {
-		expr = optimize_and_expr(state, expr);
+		expr = optimize_and_expr(opt, expr);
 	} else {
-		expr = optimize_or_expr(state, expr);
+		expr = optimize_or_expr(opt, expr);
 	}
 	if (has_parent) {
 		parent->rhs = expr;
@@ -433,38 +431,38 @@ static struct bfs_expr *de_morgan(const struct opt_state *state, struct bfs_expr
 	}
 
 	if (has_parent) {
-		parent = optimize_not_expr(state, parent);
+		parent = optimize_not_expr(opt, parent);
 	}
 	return parent;
 }
 
 /** Optimize an expression recursively. */
-static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct bfs_expr *expr);
+static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr);
 
 /**
  * Optimize a negation.
  */
-static struct bfs_expr *optimize_not_expr(const struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
 	bfs_assert(expr->eval_fn == eval_not);
 
 	struct bfs_expr *rhs = expr->rhs;
 
-	int optlevel = state->ctx->optlevel;
+	int optlevel = opt->ctx->optlevel;
 	if (optlevel >= 1) {
 		if (rhs->eval_fn == eval_true || rhs->eval_fn == eval_false) {
 			struct bfs_expr *ret = opt_const(rhs->eval_fn == eval_false);
-			opt_debug(state, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
+			opt_debug(opt, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
 			bfs_expr_free(expr);
 			return ret;
 		} else if (rhs->eval_fn == eval_not) {
-			opt_debug(state, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
+			opt_debug(opt, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
 			return extract_child_expr(expr, &rhs->rhs);
 		} else if (bfs_expr_never_returns(rhs)) {
-			opt_debug(state, 1, "reachability: %pe <==> %pe\n", expr, rhs);
+			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, rhs);
 			return extract_child_expr(expr, &expr->rhs);
 		} else if ((rhs->eval_fn == eval_and || rhs->eval_fn == eval_or)
 			   && (rhs->lhs->eval_fn == eval_not || rhs->rhs->eval_fn == eval_not)) {
-			return de_morgan(state, expr, expr->argv);
+			return de_morgan(opt, expr, expr->argv);
 		}
 	}
 
@@ -478,17 +476,17 @@ static struct bfs_expr *optimize_not_expr(const struct opt_state *state, struct
 }
 
 /** Optimize a negation recursively. */
-static struct bfs_expr *optimize_not_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
-	struct opt_state rhs_state = *state;
+static struct bfs_expr *optimize_not_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct bfs_opt rhs_state = *opt;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
 		goto fail;
 	}
 
-	state->facts_when_true = rhs_state.facts_when_false;
-	state->facts_when_false = rhs_state.facts_when_true;
+	opt->after_true = rhs_state.after_false;
+	opt->after_false = rhs_state.after_true;
 
-	return optimize_not_expr(state, expr);
+	return optimize_not_expr(opt, expr);
 
 fail:
 	bfs_expr_free(expr);
@@ -496,27 +494,27 @@ fail:
 }
 
 /** Optimize a conjunction. */
-static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
 	bfs_assert(expr->eval_fn == eval_and);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
 
-	const struct bfs_ctx *ctx = state->ctx;
+	const struct bfs_ctx *ctx = opt->ctx;
 	int optlevel = ctx->optlevel;
 	if (optlevel >= 1) {
 		if (lhs->eval_fn == eval_true) {
-			opt_debug(state, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
+			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
 			return extract_child_expr(expr, &expr->rhs);
 		} else if (rhs->eval_fn == eval_true) {
-			opt_debug(state, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
+			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (lhs->always_false) {
-			opt_debug(state, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
-			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
+			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
+			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (lhs->always_true && rhs->eval_fn == eval_false) {
-			bool debug = opt_debug(state, 1, "strength reduction: %pe <==> ", expr);
+			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
 			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
 			ret = negate_expr(ret, &fake_not_arg);
 			if (debug && ret) {
@@ -524,11 +522,11 @@ static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct
 			}
 			return ret;
 		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_false) {
-			opt_debug(state, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(state, expr->lhs, "The result of this expression is ignored.\n\n");
+			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
+			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
 			return extract_child_expr(expr, &expr->rhs);
 		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
-			return de_morgan(state, expr, expr->lhs->argv);
+			return de_morgan(opt, expr, expr->lhs->argv);
 		}
 	}
 
@@ -542,24 +540,25 @@ static struct bfs_expr *optimize_and_expr(const struct opt_state *state, struct
 }
 
 /** Optimize a conjunction recursively. */
-static struct bfs_expr *optimize_and_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
-	struct opt_state lhs_state = *state;
+static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
 		goto fail;
 	}
 
-	struct opt_state rhs_state = *state;
-	rhs_state.facts = lhs_state.facts_when_true;
+	struct bfs_opt rhs_state = *opt;
+	rhs_state.before = lhs_state.after_true;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
 		goto fail;
 	}
 
-	state->facts_when_true = rhs_state.facts_when_true;
-	facts_union(&state->facts_when_false, &lhs_state.facts_when_false, &rhs_state.facts_when_false);
+	opt->after_true = rhs_state.after_true;
+	opt->after_false = lhs_state.after_false;
+	df_join(&opt->after_false, &rhs_state.after_false);
 
-	return optimize_and_expr(state, expr);
+	return optimize_and_expr(opt, expr);
 
 fail:
 	bfs_expr_free(expr);
@@ -567,27 +566,27 @@ fail:
 }
 
 /** Optimize a disjunction. */
-static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
 	bfs_assert(expr->eval_fn == eval_or);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
 
-	const struct bfs_ctx *ctx = state->ctx;
+	const struct bfs_ctx *ctx = opt->ctx;
 	int optlevel = ctx->optlevel;
 	if (optlevel >= 1) {
 		if (lhs->always_true) {
-			opt_debug(state, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
-			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
+			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
+			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (lhs->eval_fn == eval_false) {
-			opt_debug(state, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
+			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
 			return extract_child_expr(expr, &expr->rhs);
 		} else if (rhs->eval_fn == eval_false) {
-			opt_debug(state, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
+			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (lhs->always_false && rhs->eval_fn == eval_true) {
-			bool debug = opt_debug(state, 1, "strength reduction: %pe <==> ", expr);
+			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
 			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
 			ret = negate_expr(ret, &fake_not_arg);
 			if (debug && ret) {
@@ -595,11 +594,11 @@ static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct b
 			}
 			return ret;
 		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_true) {
-			opt_debug(state, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(state, expr->lhs, "The result of this expression is ignored.\n\n");
+			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
+			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
 			return extract_child_expr(expr, &expr->rhs);
 		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
-			return de_morgan(state, expr, expr->lhs->argv);
+			return de_morgan(opt, expr, expr->lhs->argv);
 		}
 	}
 
@@ -613,24 +612,25 @@ static struct bfs_expr *optimize_or_expr(const struct opt_state *state, struct b
 }
 
 /** Optimize a disjunction recursively. */
-static struct bfs_expr *optimize_or_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
-	struct opt_state lhs_state = *state;
+static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
 		goto fail;
 	}
 
-	struct opt_state rhs_state = *state;
-	rhs_state.facts = lhs_state.facts_when_false;
+	struct bfs_opt rhs_state = *opt;
+	rhs_state.before = lhs_state.after_false;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
 		goto fail;
 	}
 
-	facts_union(&state->facts_when_true, &lhs_state.facts_when_true, &rhs_state.facts_when_true);
-	state->facts_when_false = rhs_state.facts_when_false;
+	opt->after_false = rhs_state.after_false;
+	opt->after_true = lhs_state.after_true;
+	df_join(&opt->after_true, &rhs_state.after_true);
 
-	return optimize_or_expr(state, expr);
+	return optimize_or_expr(opt, expr);
 
 fail:
 	bfs_expr_free(expr);
@@ -638,20 +638,20 @@ fail:
 }
 
 /** Optimize an expression in an ignored-result context. */
-static struct bfs_expr *ignore_result(const struct opt_state *state, struct bfs_expr *expr) {
-	int optlevel = state->ctx->optlevel;
+static struct bfs_expr *ignore_result(const struct bfs_opt *opt, struct bfs_expr *expr) {
+	int optlevel = opt->ctx->optlevel;
 
 	if (optlevel >= 1) {
 		while (true) {
 			if (expr->eval_fn == eval_not) {
-				opt_debug(state, 1, "ignored result: %pe --> %pe\n", expr, expr->rhs);
-				opt_warning(state, expr, "The result of this expression is ignored.\n\n");
+				opt_debug(opt, 1, "ignored result: %pe --> %pe\n", expr, expr->rhs);
+				opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
 				expr = extract_child_expr(expr, &expr->rhs);
 			} else if (optlevel >= 2
 			           && (expr->eval_fn == eval_and || expr->eval_fn == eval_or || expr->eval_fn == eval_comma)
 			           && expr->rhs->pure) {
-				opt_debug(state, 2, "ignored result: %pe --> %pe\n", expr, expr->lhs);
-				opt_warning(state, expr->rhs, "The result of this expression is ignored.\n\n");
+				opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, expr->lhs);
+				opt_warning(opt, expr->rhs, "The result of this expression is ignored.\n\n");
 				expr = extract_child_expr(expr, &expr->lhs);
 			} else {
 				break;
@@ -660,8 +660,8 @@ static struct bfs_expr *ignore_result(const struct opt_state *state, struct bfs_
 
 		if (optlevel >= 2 && expr->pure && expr->eval_fn != eval_false) {
 			struct bfs_expr *ret = opt_const(false);
-			opt_debug(state, 2, "ignored result: %pe --> %pe\n", expr, ret);
-			opt_warning(state, expr, "The result of this expression is ignored.\n\n");
+			opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, ret);
+			opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
 			bfs_expr_free(expr);
 			return ret;
 		}
@@ -671,27 +671,27 @@ static struct bfs_expr *ignore_result(const struct opt_state *state, struct bfs_
 }
 
 /** Optimize a comma expression. */
-static struct bfs_expr *optimize_comma_expr(const struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_comma_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
 	bfs_assert(expr->eval_fn == eval_comma);
 
 	struct bfs_expr *lhs = expr->lhs;
 	struct bfs_expr *rhs = expr->rhs;
 
-	int optlevel = state->ctx->optlevel;
+	int optlevel = opt->ctx->optlevel;
 	if (optlevel >= 1) {
-		lhs = expr->lhs = ignore_result(state, lhs);
+		lhs = expr->lhs = ignore_result(opt, lhs);
 
 		if (bfs_expr_never_returns(lhs)) {
-			opt_debug(state, 1, "reachability: %pe <==> %pe\n", expr, lhs);
-			opt_warning(state, expr->rhs, "This expression is unreachable.\n\n");
+			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, lhs);
+			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
 			return extract_child_expr(expr, &expr->lhs);
 		} else if ((lhs->always_true && rhs->eval_fn == eval_true)
 			   || (lhs->always_false && rhs->eval_fn == eval_false)) {
-			opt_debug(state, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
+			opt_debug(opt, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
 			return extract_child_expr(expr, &expr->lhs);
 		} else if (optlevel >= 2 && lhs->pure) {
-			opt_debug(state, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(state, expr->lhs, "The result of this expression is ignored.\n\n");
+			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
+			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
 			return extract_child_expr(expr, &expr->rhs);
 		}
 	}
@@ -706,76 +706,72 @@ static struct bfs_expr *optimize_comma_expr(const struct opt_state *state, struc
 }
 
 /** Optimize a comma expression recursively. */
-static struct bfs_expr *optimize_comma_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
-	struct opt_state lhs_state = *state;
+static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
 		goto fail;
 	}
 
-	struct opt_state rhs_state = *state;
-	facts_union(&rhs_state.facts, &lhs_state.facts_when_true, &lhs_state.facts_when_false);
+	struct bfs_opt rhs_state = *opt;
+	rhs_state.before = lhs_state.after_true;
+	df_join(&rhs_state.before, &lhs_state.after_false);
+
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
 		goto fail;
 	}
 
-	return optimize_comma_expr(state, expr);
+	return optimize_comma_expr(opt, expr);
 
 fail:
 	bfs_expr_free(expr);
 	return NULL;
 }
 
-/** Infer data flow facts about a predicate. */
-static void infer_pred_facts(struct opt_state *state, enum pred_type pred) {
-	constrain_pred(&state->facts_when_true.preds[pred], true);
-	constrain_pred(&state->facts_when_false.preds[pred], false);
-}
-
-/** Infer data flow facts about an icmp-style ([+-]N) expression. */
-static void infer_icmp_facts(struct opt_state *state, const struct bfs_expr *expr, enum range_type type) {
-	struct range *range_when_true = &state->facts_when_true.ranges[type];
-	struct range *range_when_false = &state->facts_when_false.ranges[type];
+/** Optimize an icmp-style ([+-]N) expression. */
+static void optimize_icmp(struct bfs_opt *opt, const struct bfs_expr *expr, enum range_type type) {
+	struct df_range *true_range = &opt->after_true.ranges[type];
+	struct df_range *false_range = &opt->after_false.ranges[type];
 	long long value = expr->num;
 
 	switch (expr->int_cmp) {
 	case BFS_INT_EQUAL:
-		constrain_min(range_when_true, value);
-		constrain_max(range_when_true, value);
-		range_remove(range_when_false, value);
+		constrain_min(true_range, value);
+		constrain_max(true_range, value);
+		range_remove(false_range, value);
 		break;
 
 	case BFS_INT_LESS:
-		constrain_min(range_when_false, value);
-		constrain_max(range_when_true, value);
-		range_remove(range_when_true, value);
+		constrain_min(false_range, value);
+		constrain_max(true_range, value);
+		range_remove(true_range, value);
 		break;
 
 	case BFS_INT_GREATER:
-		constrain_max(range_when_false, value);
-		constrain_min(range_when_true, value);
-		range_remove(range_when_true, value);
+		constrain_max(false_range, value);
+		constrain_min(true_range, value);
+		range_remove(true_range, value);
 		break;
 	}
 }
 
 /** Optimize -{execut,read,writ}able. */
-static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_access(struct bfs_opt *opt, struct bfs_expr *expr) {
 	expr->probability = 1.0;
 
 	if (expr->num & R_OK) {
-		infer_pred_facts(state, READABLE_PRED);
+		opt_constrain_pred(opt, READABLE_PRED, true);
 		expr->probability *= 0.99;
 	}
 
 	if (expr->num & W_OK) {
-		infer_pred_facts(state, WRITABLE_PRED);
+		opt_constrain_pred(opt, WRITABLE_PRED, true);
 		expr->probability *= 0.8;
 	}
 
 	if (expr->num & X_OK) {
-		infer_pred_facts(state, EXECUTABLE_PRED);
+		opt_constrain_pred(opt, EXECUTABLE_PRED, true);
 		expr->probability *= 0.2;
 	}
 
@@ -783,8 +779,8 @@ static struct bfs_expr *optimize_access(struct opt_state *state, struct bfs_expr
 }
 
 /** Optimize -empty. */
-static struct bfs_expr *optimize_empty(struct opt_state *state, struct bfs_expr *expr) {
-	if (state->ctx->optlevel >= 4) {
+static struct bfs_expr *optimize_empty(struct bfs_opt *opt, struct bfs_expr *expr) {
+	if (opt->ctx->optlevel >= 4) {
 		// Since -empty attempts to open and read directories, it may
 		// have side effects such as reporting permission errors, and
 		// thus shouldn't be re-ordered without aggressive optimizations
@@ -795,7 +791,7 @@ static struct bfs_expr *optimize_empty(struct opt_state *state, struct bfs_expr
 }
 
 /** Optimize -{exec,ok}{,dir}. */
-static struct bfs_expr *optimize_exec(struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_exec(struct bfs_opt *opt, struct bfs_expr *expr) {
 	if (expr->exec->flags & BFS_EXEC_MULTI) {
 		expr->always_true = true;
 	} else {
@@ -806,7 +802,7 @@ static struct bfs_expr *optimize_exec(struct opt_state *state, struct bfs_expr *
 }
 
 /** Optimize -name/-lname/-path. */
-static struct bfs_expr *optimize_fnmatch(struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_fnmatch(struct bfs_opt *opt, struct bfs_expr *expr) {
 	if (strchr(expr->argv[1], '*')) {
 		expr->probability = 0.5;
 	} else {
@@ -817,13 +813,13 @@ static struct bfs_expr *optimize_fnmatch(struct opt_state *state, struct bfs_exp
 }
 
 /** Optimize -gid. */
-static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range = &state->facts_when_true.ranges[GID_RANGE];
+static struct bfs_expr *optimize_gid(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[GID_RANGE];
 	if (range->min == range->max) {
 		gid_t gid = range->min;
-		bool nogroup = !bfs_getgrgid(state->ctx->groups, gid);
+		bool nogroup = !bfs_getgrgid(opt->ctx->groups, gid);
 		if (errno == 0) {
-			constrain_pred(&state->facts_when_true.preds[NOGROUP_PRED], nogroup);
+			opt_constrain_pred(opt, NOGROUP_PRED, nogroup);
 		}
 	}
 
@@ -831,8 +827,8 @@ static struct bfs_expr *optimize_gid(struct opt_state *state, struct bfs_expr *e
 }
 
 /** Optimize -inum. */
-static struct bfs_expr *optimize_inum(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range = &state->facts_when_true.ranges[INUM_RANGE];
+static struct bfs_expr *optimize_inum(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[INUM_RANGE];
 	if (range->min == range->max) {
 		expr->probability = 0.01;
 	} else {
@@ -843,8 +839,8 @@ static struct bfs_expr *optimize_inum(struct opt_state *state, struct bfs_expr *
 }
 
 /** Optimize -links. */
-static struct bfs_expr *optimize_links(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range = &state->facts_when_true.ranges[LINKS_RANGE];
+static struct bfs_expr *optimize_links(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[LINKS_RANGE];
 	if (1 >= range->min && 1 <= range->max) {
 		expr->probability = 0.99;
 	} else {
@@ -855,13 +851,13 @@ static struct bfs_expr *optimize_links(struct opt_state *state, struct bfs_expr
 }
 
 /** Optimize -uid. */
-static struct bfs_expr *optimize_uid(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range = &state->facts_when_true.ranges[UID_RANGE];
+static struct bfs_expr *optimize_uid(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[UID_RANGE];
 	if (range->min == range->max) {
 		uid_t uid = range->min;
-		bool nouser = !bfs_getpwuid(state->ctx->users, uid);
+		bool nouser = !bfs_getpwuid(opt->ctx->users, uid);
 		if (errno == 0) {
-			constrain_pred(&state->facts_when_true.preds[NOUSER_PRED], nouser);
+			opt_constrain_pred(opt, NOUSER_PRED, nouser);
 		}
 	}
 
@@ -869,16 +865,16 @@ static struct bfs_expr *optimize_uid(struct opt_state *state, struct bfs_expr *e
 }
 
 /** Optimize -samefile. */
-static struct bfs_expr *optimize_samefile(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range_when_true = &state->facts_when_true.ranges[INUM_RANGE];
-	constrain_min(range_when_true, expr->ino);
-	constrain_max(range_when_true, expr->ino);
+static struct bfs_expr *optimize_samefile(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[INUM_RANGE];
+	constrain_min(range, expr->ino);
+	constrain_max(range, expr->ino);
 	return expr;
 }
 
 /** Optimize -size. */
-static struct bfs_expr *optimize_size(struct opt_state *state, struct bfs_expr *expr) {
-	struct range *range = &state->facts_when_true.ranges[SIZE_RANGE];
+static struct bfs_expr *optimize_size(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_range *range = &opt->after_true.ranges[SIZE_RANGE];
 	if (range->min == range->max) {
 		expr->probability = 0.01;
 	} else {
@@ -923,9 +919,9 @@ static void estimate_type_probability(struct bfs_expr *expr) {
 }
 
 /** Optimize -type. */
-static struct bfs_expr *optimize_type(struct opt_state *state, struct bfs_expr *expr) {
-	state->facts_when_true.types &= expr->num;
-	state->facts_when_false.types &= ~expr->num;
+static struct bfs_expr *optimize_type(struct bfs_opt *opt, struct bfs_expr *expr) {
+	opt->after_true.types &= expr->num;
+	opt->after_false.types &= ~expr->num;
 
 	estimate_type_probability(expr);
 
@@ -933,16 +929,16 @@ static struct bfs_expr *optimize_type(struct opt_state *state, struct bfs_expr *
 }
 
 /** Optimize -xtype. */
-static struct bfs_expr *optimize_xtype(struct opt_state *state, struct bfs_expr *expr) {
-	if (state->ctx->optlevel >= 4) {
+static struct bfs_expr *optimize_xtype(struct bfs_opt *opt, struct bfs_expr *expr) {
+	if (opt->ctx->optlevel >= 4) {
 		// Since -xtype dereferences symbolic links, it may have side
 		// effects such as reporting permission errors, and thus
 		// shouldn't be re-ordered without aggressive optimizations
 		expr->pure = true;
 	}
 
-	state->facts_when_true.xtypes &= expr->num;
-	state->facts_when_false.xtypes &= ~expr->num;
+	opt->after_true.xtypes &= expr->num;
+	opt->after_false.xtypes &= ~expr->num;
 
 	estimate_type_probability(expr);
 
@@ -1115,7 +1111,7 @@ static const struct {
 };
 
 /** Signature for custom optimizer functions. */
-typedef struct bfs_expr *bfs_opt_fn(struct opt_state *state, struct bfs_expr *expr);
+typedef struct bfs_expr *bfs_opt_fn(struct bfs_opt *opt, struct bfs_expr *expr);
 
 /** Table of custom optimizer functions. */
 static const struct {
@@ -1150,7 +1146,7 @@ static const struct {
 /**
  * Look up the appropriate optimizer for an expression and call it.
  */
-static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs_expr *expr) {
+static struct bfs_expr *optimize_expr_lookup(struct bfs_opt *opt, struct bfs_expr *expr) {
 	for (size_t i = 0; i < countof(opt_pure); ++i) {
 		if (opt_pure[i] == expr->eval_fn) {
 			expr->pure = true;
@@ -1189,42 +1185,42 @@ static struct bfs_expr *optimize_expr_lookup(struct opt_state *state, struct bfs
 
 	for (size_t i = 0; i < countof(opt_preds); ++i) {
 		if (opt_preds[i].eval_fn == expr->eval_fn) {
-			infer_pred_facts(state, opt_preds[i].pred);
+			opt_constrain_pred(opt, opt_preds[i].pred, true);
 			break;
 		}
 	}
 
 	for (size_t i = 0; i < countof(opt_ranges); ++i) {
 		if (opt_ranges[i].eval_fn == expr->eval_fn) {
-			infer_icmp_facts(state, expr, opt_ranges[i].range);
+			optimize_icmp(opt, expr, opt_ranges[i].range);
 			break;
 		}
 	}
 
 	for (size_t i = 0; i < countof(opt_fns); ++i) {
 		if (opt_fns[i].eval_fn == expr->eval_fn) {
-			return opt_fns[i].opt_fn(state, expr);
+			return opt_fns[i].opt_fn(opt, expr);
 		}
 	}
 
 	return expr;
 }
 
-static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct bfs_expr *expr) {
-	int optlevel = state->ctx->optlevel;
+static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
+	int optlevel = opt->ctx->optlevel;
 
-	state->facts_when_true = state->facts;
-	state->facts_when_false = state->facts;
+	opt->after_true = opt->before;
+	opt->after_false = opt->before;
 
-	if (optlevel >= 2 && facts_are_impossible(&state->facts)) {
+	if (optlevel >= 2 && df_is_bottom(&opt->before)) {
 		struct bfs_expr *ret = opt_const(false);
-		opt_debug(state, 2, "reachability: %pe --> %pe\n", expr, ret);
-		opt_warning(state, expr, "This expression is unreachable.\n\n");
+		opt_debug(opt, 2, "reachability: %pe --> %pe\n", expr, ret);
+		opt_warning(opt, expr, "This expression is unreachable.\n\n");
 		bfs_expr_free(expr);
 		return ret;
 	}
 
-	expr = optimize_expr_lookup(state, expr);
+	expr = optimize_expr_lookup(opt, expr);
 	if (!expr) {
 		return NULL;
 	}
@@ -1243,38 +1239,38 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 			}
 		}
 	} else if (!expr->pure) {
-		facts_union(state->facts_when_impure, state->facts_when_impure, &state->facts);
+		df_join(opt->impure, &opt->before);
 	}
 
 	if (expr->always_true) {
 		expr->probability = 1.0;
-		set_facts_impossible(&state->facts_when_false);
+		df_init_bottom(&opt->after_false);
 	}
 	if (expr->always_false) {
 		expr->probability = 0.0;
-		set_facts_impossible(&state->facts_when_true);
+		df_init_bottom(&opt->after_true);
 	}
 
 	if (optlevel < 2 || expr->eval_fn == eval_true || expr->eval_fn == eval_false) {
 		return expr;
 	}
 
-	if (facts_are_impossible(&state->facts_when_true)) {
+	if (df_is_bottom(&opt->after_true)) {
 		if (expr->pure) {
 			struct bfs_expr *ret = opt_const(false);
-			opt_warning(state, expr, "This expression is always false.\n\n");
-			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, ret);
+			opt_warning(opt, expr, "This expression is always false.\n\n");
+			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
 			bfs_expr_free(expr);
 			return ret;
 		} else {
 			expr->always_false = true;
 			expr->probability = 0.0;
 		}
-	} else if (facts_are_impossible(&state->facts_when_false)) {
+	} else if (df_is_bottom(&opt->after_false)) {
 		if (expr->pure) {
 			struct bfs_expr *ret = opt_const(true);
-			opt_debug(state, 2, "data flow: %pe --> %pe\n", expr, ret);
-			opt_warning(state, expr, "This expression is always true.\n\n");
+			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
+			opt_warning(opt, expr, "This expression is always true.\n\n");
 			bfs_expr_free(expr);
 			return ret;
 		} else {
@@ -1287,14 +1283,14 @@ static struct bfs_expr *optimize_expr_recursive(struct opt_state *state, struct
 }
 
 /** Swap the children of a binary expression if it would reduce the cost. */
-static bool reorder_expr(const struct opt_state *state, struct bfs_expr *expr, float swapped_cost) {
+static bool reorder_expr(const struct bfs_opt *opt, struct bfs_expr *expr, float swapped_cost) {
 	if (swapped_cost < expr->cost) {
-		bool debug = opt_debug(state, 3, "cost: %pe <==> ", expr);
+		bool debug = opt_debug(opt, 3, "cost: %pe <==> ", expr);
 		struct bfs_expr *lhs = expr->lhs;
 		expr->lhs = expr->rhs;
 		expr->rhs = lhs;
 		if (debug) {
-			cfprintf(state->ctx->cerr, "%pe (~${ylw}%g${rs} --> ~${ylw}%g${rs})\n", expr, expr->cost, swapped_cost);
+			cfprintf(opt->ctx->cerr, "%pe (~${ylw}%g${rs} --> ~${ylw}%g${rs})\n", expr, expr->cost, swapped_cost);
 		}
 		expr->cost = swapped_cost;
 		return true;
@@ -1311,7 +1307,7 @@ static bool reorder_expr(const struct opt_state *state, struct bfs_expr *expr, f
  * @return
  *         Whether any subexpression was reordered.
  */
-static bool reorder_expr_recursive(const struct opt_state *state, struct bfs_expr *expr) {
+static bool reorder_expr_recursive(const struct bfs_opt *opt, struct bfs_expr *expr) {
 	if (!bfs_expr_is_parent(expr)) {
 		return false;
 	}
@@ -1321,17 +1317,17 @@ static bool reorder_expr_recursive(const struct opt_state *state, struct bfs_exp
 
 	bool ret = false;
 	if (lhs) {
-		ret |= reorder_expr_recursive(state, lhs);
+		ret |= reorder_expr_recursive(opt, lhs);
 	}
 	if (rhs) {
-		ret |= reorder_expr_recursive(state, rhs);
+		ret |= reorder_expr_recursive(opt, rhs);
 	}
 
 	if (expr->eval_fn == eval_and || expr->eval_fn == eval_or) {
 		if (lhs->pure && rhs->pure) {
 			float rhs_prob = expr->eval_fn == eval_and ? rhs->probability : 1.0 - rhs->probability;
 			float swapped_cost = rhs->cost + rhs_prob * lhs->cost;
-			ret |= reorder_expr(state, expr, swapped_cost);
+			ret |= reorder_expr(opt, expr, swapped_cost);
 		}
 	}
 
@@ -1341,18 +1337,18 @@ static bool reorder_expr_recursive(const struct opt_state *state, struct bfs_exp
 /**
  * Optimize a top-level expression.
  */
-static struct bfs_expr *optimize_expr(struct opt_state *state, struct bfs_expr *expr) {
-	struct opt_facts saved_impure = *state->facts_when_impure;
+static struct bfs_expr *optimize_expr(struct bfs_opt *opt, struct bfs_expr *expr) {
+	struct df_domain saved_impure = *opt->impure;
 
-	expr = optimize_expr_recursive(state, expr);
+	expr = optimize_expr_recursive(opt, expr);
 	if (!expr) {
 		return NULL;
 	}
 
-	if (state->ctx->optlevel >= 3 && reorder_expr_recursive(state, expr)) {
+	if (opt->ctx->optlevel >= 3 && reorder_expr_recursive(opt, expr)) {
 		// Re-do optimizations to account for the new ordering
-		*state->facts_when_impure = saved_impure;
-		expr = optimize_expr_recursive(state, expr);
+		*opt->impure = saved_impure;
+		expr = optimize_expr_recursive(opt, expr);
 		if (!expr) {
 			return NULL;
 		}
@@ -1364,41 +1360,41 @@ static struct bfs_expr *optimize_expr(struct opt_state *state, struct bfs_expr *
 int bfs_optimize(struct bfs_ctx *ctx) {
 	bfs_ctx_dump(ctx, DEBUG_OPT);
 
-	struct opt_facts facts_when_impure;
-	set_facts_impossible(&facts_when_impure);
+	struct df_domain impure;
+	df_init_bottom(&impure);
 
-	struct opt_state state = {
+	struct bfs_opt opt = {
 		.ctx = ctx,
-		.facts_when_impure = &facts_when_impure,
+		.impure = &impure,
 	};
-	facts_init(&state.facts);
+	df_init_top(&opt.before);
 
-	ctx->exclude = optimize_expr(&state, ctx->exclude);
+	ctx->exclude = optimize_expr(&opt, ctx->exclude);
 	if (!ctx->exclude) {
 		return -1;
 	}
 
 	// Only non-excluded files are evaluated
-	state.facts = state.facts_when_false;
+	opt.before = opt.after_false;
 
-	struct range *depth = &state.facts.ranges[DEPTH_RANGE];
+	struct df_range *depth = &opt.before.ranges[DEPTH_RANGE];
 	constrain_min(depth, ctx->mindepth);
 	constrain_max(depth, ctx->maxdepth);
 
-	ctx->expr = optimize_expr(&state, ctx->expr);
+	ctx->expr = optimize_expr(&opt, ctx->expr);
 	if (!ctx->expr) {
 		return -1;
 	}
 
-	ctx->expr = ignore_result(&state, ctx->expr);
+	ctx->expr = ignore_result(&opt, ctx->expr);
 
-	if (facts_are_impossible(&facts_when_impure)) {
+	if (df_is_bottom(&impure)) {
 		bfs_warning(ctx, "This command won't do anything.\n\n");
 	}
 
-	const struct range *depth_when_impure = &facts_when_impure.ranges[DEPTH_RANGE];
-	long long mindepth = depth_when_impure->min;
-	long long maxdepth = depth_when_impure->max;
+	const struct df_range *impure_depth = &impure.ranges[DEPTH_RANGE];
+	long long mindepth = impure_depth->min;
+	long long maxdepth = impure_depth->max;
 
 	int optlevel = ctx->optlevel;
 
@@ -1407,7 +1403,7 @@ int bfs_optimize(struct bfs_ctx *ctx) {
 			mindepth = INT_MAX;
 		}
 		ctx->mindepth = mindepth;
-		opt_debug(&state, 2, "data flow: mindepth --> %d\n", ctx->mindepth);
+		opt_debug(&opt, 2, "data flow: mindepth --> %d\n", ctx->mindepth);
 	}
 
 	if (optlevel >= 4 && maxdepth < ctx->maxdepth) {
@@ -1415,7 +1411,7 @@ int bfs_optimize(struct bfs_ctx *ctx) {
 			maxdepth = INT_MIN;
 		}
 		ctx->maxdepth = maxdepth;
-		opt_debug(&state, 4, "data flow: maxdepth --> %d\n", ctx->maxdepth);
+		opt_debug(&opt, 4, "data flow: maxdepth --> %d\n", ctx->maxdepth);
 	}
 
 	return 0;
-- 
cgit v1.2.3


From 70092ae5c8f83a99fbc98dc8e2ca2eaab676a5a8 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 20 Dec 2023 20:18:35 -0500
Subject: expr: Arena-allocate expressions

---
 src/ctx.c   |  11 +-
 src/ctx.h   |   6 ++
 src/expr.c  |  22 ++--
 src/expr.h  |  19 +++-
 src/opt.c   | 113 +++++++-------------
 src/parse.c | 340 +++++++++++++++++++++++-------------------------------------
 6 files changed, 210 insertions(+), 301 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/ctx.c b/src/ctx.c
index f5dc465..a3c5140 100644
--- a/src/ctx.c
+++ b/src/ctx.c
@@ -22,6 +22,9 @@ struct bfs_ctx *bfs_ctx_new(void) {
 		return NULL;
 	}
 
+	SLIST_INIT(&ctx->expr_list);
+	ARENA_INIT(&ctx->expr_arena, struct bfs_expr);
+
 	ctx->maxdepth = INT_MAX;
 	ctx->flags = BFTW_RECOVER;
 	ctx->strategy = BFTW_BFS;
@@ -202,9 +205,6 @@ int bfs_ctx_free(struct bfs_ctx *ctx) {
 		CFILE *cout = ctx->cout;
 		CFILE *cerr = ctx->cerr;
 
-		bfs_expr_free(ctx->exclude);
-		bfs_expr_free(ctx->expr);
-
 		bfs_mtab_free(ctx->mtab);
 
 		bfs_groups_free(ctx->groups);
@@ -241,6 +241,11 @@ int bfs_ctx_free(struct bfs_ctx *ctx) {
 
 		free_colors(ctx->colors);
 
+		for_slist (struct bfs_expr, expr, &ctx->expr_list) {
+			bfs_expr_clear(expr);
+		}
+		arena_destroy(&ctx->expr_arena);
+
 		for (size_t i = 0; i < ctx->npaths; ++i) {
 			free((char *)ctx->paths[i]);
 		}
diff --git a/src/ctx.h b/src/ctx.h
index 75891da..aa91f2c 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -8,9 +8,11 @@
 #ifndef BFS_CTX_H
 #define BFS_CTX_H
 
+#include "alloc.h"
 #include "bftw.h"
 #include "config.h"
 #include "diag.h"
+#include "expr.h"
 #include "trie.h"
 #include <stddef.h>
 #include <sys/resource.h>
@@ -34,6 +36,10 @@ struct bfs_ctx {
 	struct bfs_expr *expr;
 	/** An expression for files to filter out. */
 	struct bfs_expr *exclude;
+	/** A list of allocated expressions. */
+	struct bfs_exprs expr_list;
+	/** bfs_expr arena. */
+	struct arena expr_arena;
 
 	/** -mindepth option. */
 	int mindepth;
diff --git a/src/expr.c b/src/expr.c
index 380038c..2002fc7 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3,24 +3,27 @@
 
 #include "expr.h"
 #include "alloc.h"
+#include "ctx.h"
 #include "eval.h"
 #include "exec.h"
 #include "printf.h"
 #include "xregex.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
-struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval_fn, size_t argc, char **argv) {
-	struct bfs_expr *expr = ZALLOC(struct bfs_expr);
+struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t argc, char **argv) {
+	struct bfs_expr *expr = arena_alloc(&ctx->expr_arena);
 	if (!expr) {
-		perror("zalloc()");
 		return NULL;
 	}
 
+	memset(expr, 0, sizeof(*expr));
 	expr->eval_fn = eval_fn;
 	expr->argc = argc;
 	expr->argv = argv;
 	expr->probability = 0.5;
+	SLIST_PREPEND(&ctx->expr_list, expr);
 	return expr;
 }
 
@@ -36,21 +39,12 @@ bool bfs_expr_never_returns(const struct bfs_expr *expr) {
 	return expr->always_true && expr->always_false;
 }
 
-void bfs_expr_free(struct bfs_expr *expr) {
-	if (!expr) {
-		return;
-	}
-
-	if (bfs_expr_is_parent(expr)) {
-		bfs_expr_free(expr->rhs);
-		bfs_expr_free(expr->lhs);
-	} else if (expr->eval_fn == eval_exec) {
+void bfs_expr_clear(struct bfs_expr *expr) {
+	if (expr->eval_fn == eval_exec) {
 		bfs_exec_free(expr->exec);
 	} else if (expr->eval_fn == eval_fprintf) {
 		bfs_printf_free(expr->printf);
 	} else if (expr->eval_fn == eval_regex) {
 		bfs_regfree(expr->regex);
 	}
-
-	free(expr);
 }
diff --git a/src/expr.h b/src/expr.h
index 95118b9..290f1f8 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -74,10 +74,21 @@ enum bfs_size_unit {
 	BFS_PB,
 };
 
+/**
+ * A linked list of expressions.
+ */
+struct bfs_exprs {
+	struct bfs_expr *head;
+	struct bfs_expr **tail;
+};
+
 /**
  * A command line expression.
  */
 struct bfs_expr {
+	/** The next allocated expression. */
+	struct bfs_expr *next;
+
 	/** The function that evaluates this expression. */
 	bfs_eval_fn *eval_fn;
 
@@ -199,10 +210,12 @@ struct bfs_expr {
 	};
 };
 
+struct bfs_ctx;
+
 /**
  * Create a new expression.
  */
-struct bfs_expr *bfs_expr_new(bfs_eval_fn *eval, size_t argc, char **argv);
+struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval, size_t argc, char **argv);
 
 /**
  * @return Whether the expression has child expressions.
@@ -220,8 +233,8 @@ bool bfs_expr_never_returns(const struct bfs_expr *expr);
 bool bfs_expr_cmp(const struct bfs_expr *expr, long long n);
 
 /**
- * Free an expression tree.
+ * Free any resources owned by an expression.
  */
-void bfs_expr_free(struct bfs_expr *expr);
+void bfs_expr_clear(struct bfs_expr *expr);
 
 #endif // BFS_EXPR_H
diff --git a/src/opt.c b/src/opt.c
index a989670..1dc985a 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -284,7 +284,7 @@ static void df_join(struct df_domain *dest, const struct df_domain *src) {
  */
 struct bfs_opt {
 	/** The context we're optimizing. */
-	const struct bfs_ctx *ctx;
+	struct bfs_ctx *ctx;
 
 	/** Data flow state before this expression is evaluated. */
 	struct df_domain before;
@@ -330,31 +330,22 @@ static void opt_warning(const struct bfs_opt *opt, const struct bfs_expr *expr,
 }
 
 /** Create a constant expression. */
-static struct bfs_expr *opt_const(bool value) {
+static struct bfs_expr *opt_const(const struct bfs_opt *opt, bool value) {
 	static bfs_eval_fn *fns[] = {eval_false, eval_true};
 	static char *fake_args[] = {"-false", "-true"};
-	return bfs_expr_new(fns[value], 1, &fake_args[value]);
-}
-
-/** Extract a child expression, freeing the outer expression. */
-static struct bfs_expr *extract_child_expr(struct bfs_expr *expr, struct bfs_expr **child) {
-	struct bfs_expr *ret = *child;
-	*child = NULL;
-	bfs_expr_free(expr);
-	return ret;
+	return bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value]);
 }
 
 /**
  * Negate an expression.
  */
-static struct bfs_expr *negate_expr(struct bfs_expr *rhs, char **argv) {
+static struct bfs_expr *negate_expr(const struct bfs_opt *opt, struct bfs_expr *rhs, char **argv) {
 	if (rhs->eval_fn == eval_not) {
-		return extract_child_expr(rhs, &rhs->rhs);
+		return rhs->rhs;
 	}
 
-	struct bfs_expr *expr = bfs_expr_new(eval_not, 1, argv);
+	struct bfs_expr *expr = bfs_expr_new(opt->ctx, eval_not, 1, argv);
 	if (!expr) {
-		bfs_expr_free(rhs);
 		return NULL;
 	}
 
@@ -373,7 +364,7 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
 static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *expr, char **argv) {
 	bool debug = opt_debug(opt, 1, "De Morgan's laws: %pe ", expr);
 
-	struct bfs_expr *parent = negate_expr(expr, argv);
+	struct bfs_expr *parent = negate_expr(opt, expr, argv);
 	if (!parent) {
 		return NULL;
 	}
@@ -393,10 +384,9 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
 		expr->argv = &fake_and_arg;
 	}
 
-	expr->lhs = negate_expr(expr->lhs, argv);
-	expr->rhs = negate_expr(expr->rhs, argv);
+	expr->lhs = negate_expr(opt, expr->lhs, argv);
+	expr->rhs = negate_expr(opt, expr->rhs, argv);
 	if (!expr->lhs || !expr->rhs) {
-		bfs_expr_free(parent);
 		return NULL;
 	}
 
@@ -411,7 +401,6 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
 		expr->rhs = optimize_not_expr(opt, expr->rhs);
 	}
 	if (!expr->lhs || !expr->rhs) {
-		bfs_expr_free(parent);
 		return NULL;
 	}
 
@@ -426,7 +415,6 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
 		parent = expr;
 	}
 	if (!expr) {
-		bfs_expr_free(parent);
 		return NULL;
 	}
 
@@ -450,16 +438,15 @@ static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_
 	int optlevel = opt->ctx->optlevel;
 	if (optlevel >= 1) {
 		if (rhs->eval_fn == eval_true || rhs->eval_fn == eval_false) {
-			struct bfs_expr *ret = opt_const(rhs->eval_fn == eval_false);
+			struct bfs_expr *ret = opt_const(opt, rhs->eval_fn == eval_false);
 			opt_debug(opt, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
-			bfs_expr_free(expr);
 			return ret;
 		} else if (rhs->eval_fn == eval_not) {
 			opt_debug(opt, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
-			return extract_child_expr(expr, &rhs->rhs);
+			return rhs->rhs;
 		} else if (bfs_expr_never_returns(rhs)) {
 			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, rhs);
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		} else if ((rhs->eval_fn == eval_and || rhs->eval_fn == eval_or)
 			   && (rhs->lhs->eval_fn == eval_not || rhs->rhs->eval_fn == eval_not)) {
 			return de_morgan(opt, expr, expr->argv);
@@ -480,17 +467,13 @@ static struct bfs_expr *optimize_not_expr_recursive(struct bfs_opt *opt, struct
 	struct bfs_opt rhs_state = *opt;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
-		goto fail;
+		return NULL;
 	}
 
 	opt->after_true = rhs_state.after_false;
 	opt->after_false = rhs_state.after_true;
 
 	return optimize_not_expr(opt, expr);
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /** Optimize a conjunction. */
@@ -505,18 +488,18 @@ static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_
 	if (optlevel >= 1) {
 		if (lhs->eval_fn == eval_true) {
 			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		} else if (rhs->eval_fn == eval_true) {
 			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if (lhs->always_false) {
 			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
 			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if (lhs->always_true && rhs->eval_fn == eval_false) {
 			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
-			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
-			ret = negate_expr(ret, &fake_not_arg);
+			struct bfs_expr *ret = expr->lhs;
+			ret = negate_expr(opt, ret, &fake_not_arg);
 			if (debug && ret) {
 				cfprintf(ctx->cerr, "%pe\n", ret);
 			}
@@ -524,7 +507,7 @@ static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_
 		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_false) {
 			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
 			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
 			return de_morgan(opt, expr, expr->lhs->argv);
 		}
@@ -544,14 +527,14 @@ static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct
 	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
-		goto fail;
+		return NULL;
 	}
 
 	struct bfs_opt rhs_state = *opt;
 	rhs_state.before = lhs_state.after_true;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
-		goto fail;
+		return NULL;
 	}
 
 	opt->after_true = rhs_state.after_true;
@@ -559,10 +542,6 @@ static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct
 	df_join(&opt->after_false, &rhs_state.after_false);
 
 	return optimize_and_expr(opt, expr);
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /** Optimize a disjunction. */
@@ -578,17 +557,17 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
 		if (lhs->always_true) {
 			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
 			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if (lhs->eval_fn == eval_false) {
 			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		} else if (rhs->eval_fn == eval_false) {
 			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if (lhs->always_false && rhs->eval_fn == eval_true) {
 			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
-			struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
-			ret = negate_expr(ret, &fake_not_arg);
+			struct bfs_expr *ret = expr->lhs;
+			ret = negate_expr(opt, ret, &fake_not_arg);
 			if (debug && ret) {
 				cfprintf(ctx->cerr, "%pe\n", ret);
 			}
@@ -596,7 +575,7 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
 		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_true) {
 			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
 			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
 			return de_morgan(opt, expr, expr->lhs->argv);
 		}
@@ -616,14 +595,14 @@ static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct b
 	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
-		goto fail;
+		return NULL;
 	}
 
 	struct bfs_opt rhs_state = *opt;
 	rhs_state.before = lhs_state.after_false;
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
-		goto fail;
+		return NULL;
 	}
 
 	opt->after_false = rhs_state.after_false;
@@ -631,10 +610,6 @@ static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct b
 	df_join(&opt->after_true, &rhs_state.after_true);
 
 	return optimize_or_expr(opt, expr);
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /** Optimize an expression in an ignored-result context. */
@@ -646,23 +621,22 @@ static struct bfs_expr *ignore_result(const struct bfs_opt *opt, struct bfs_expr
 			if (expr->eval_fn == eval_not) {
 				opt_debug(opt, 1, "ignored result: %pe --> %pe\n", expr, expr->rhs);
 				opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
-				expr = extract_child_expr(expr, &expr->rhs);
+				expr = expr->rhs;
 			} else if (optlevel >= 2
 			           && (expr->eval_fn == eval_and || expr->eval_fn == eval_or || expr->eval_fn == eval_comma)
 			           && expr->rhs->pure) {
 				opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, expr->lhs);
 				opt_warning(opt, expr->rhs, "The result of this expression is ignored.\n\n");
-				expr = extract_child_expr(expr, &expr->lhs);
+				expr = expr->lhs;
 			} else {
 				break;
 			}
 		}
 
 		if (optlevel >= 2 && expr->pure && expr->eval_fn != eval_false) {
-			struct bfs_expr *ret = opt_const(false);
+			struct bfs_expr *ret = opt_const(opt, false);
 			opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, ret);
 			opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
-			bfs_expr_free(expr);
 			return ret;
 		}
 	}
@@ -684,15 +658,15 @@ static struct bfs_expr *optimize_comma_expr(const struct bfs_opt *opt, struct bf
 		if (bfs_expr_never_returns(lhs)) {
 			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, lhs);
 			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if ((lhs->always_true && rhs->eval_fn == eval_true)
 			   || (lhs->always_false && rhs->eval_fn == eval_false)) {
 			opt_debug(opt, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
-			return extract_child_expr(expr, &expr->lhs);
+			return expr->lhs;
 		} else if (optlevel >= 2 && lhs->pure) {
 			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
 			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return extract_child_expr(expr, &expr->rhs);
+			return expr->rhs;
 		}
 	}
 
@@ -710,7 +684,7 @@ static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struc
 	struct bfs_opt lhs_state = *opt;
 	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
 	if (!expr->lhs) {
-		goto fail;
+		return NULL;
 	}
 
 	struct bfs_opt rhs_state = *opt;
@@ -719,14 +693,10 @@ static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struc
 
 	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
 	if (!expr->rhs) {
-		goto fail;
+		return NULL;
 	}
 
 	return optimize_comma_expr(opt, expr);
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /** Optimize an icmp-style ([+-]N) expression. */
@@ -1213,10 +1183,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
 	opt->after_false = opt->before;
 
 	if (optlevel >= 2 && df_is_bottom(&opt->before)) {
-		struct bfs_expr *ret = opt_const(false);
+		struct bfs_expr *ret = opt_const(opt, false);
 		opt_debug(opt, 2, "reachability: %pe --> %pe\n", expr, ret);
 		opt_warning(opt, expr, "This expression is unreachable.\n\n");
-		bfs_expr_free(expr);
 		return ret;
 	}
 
@@ -1257,10 +1226,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
 
 	if (df_is_bottom(&opt->after_true)) {
 		if (expr->pure) {
-			struct bfs_expr *ret = opt_const(false);
+			struct bfs_expr *ret = opt_const(opt, false);
 			opt_warning(opt, expr, "This expression is always false.\n\n");
 			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
-			bfs_expr_free(expr);
 			return ret;
 		} else {
 			expr->always_false = true;
@@ -1268,10 +1236,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
 		}
 	} else if (df_is_bottom(&opt->after_false)) {
 		if (expr->pure) {
-			struct bfs_expr *ret = opt_const(true);
+			struct bfs_expr *ret = opt_const(opt, true);
 			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
 			opt_warning(opt, expr, "This expression is always true.\n\n");
-			bfs_expr_free(expr);
 			return ret;
 		} else {
 			expr->always_true = true;
diff --git a/src/parse.c b/src/parse.c
index 18a1064..17fe8ad 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -54,50 +54,6 @@ static char *fake_or_arg = "-o";
 static char *fake_print_arg = "-print";
 static char *fake_true_arg = "-true";
 
-/**
- * Create a new unary expression.
- */
-static struct bfs_expr *new_unary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *rhs, char **argv) {
-	struct bfs_expr *expr = bfs_expr_new(eval_fn, 1, argv);
-	if (!expr) {
-		bfs_expr_free(rhs);
-		return NULL;
-	}
-
-	expr->lhs = NULL;
-	expr->rhs = rhs;
-	bfs_assert(bfs_expr_is_parent(expr));
-
-	expr->persistent_fds = rhs->persistent_fds;
-	expr->ephemeral_fds = rhs->ephemeral_fds;
-	return expr;
-}
-
-/**
- * Create a new binary expression.
- */
-static struct bfs_expr *new_binary_expr(bfs_eval_fn *eval_fn, struct bfs_expr *lhs, struct bfs_expr *rhs, char **argv) {
-	struct bfs_expr *expr = bfs_expr_new(eval_fn, 1, argv);
-	if (!expr) {
-		bfs_expr_free(rhs);
-		bfs_expr_free(lhs);
-		return NULL;
-	}
-
-	expr->lhs = lhs;
-	expr->rhs = rhs;
-	bfs_assert(bfs_expr_is_parent(expr));
-
-	expr->persistent_fds = lhs->persistent_fds + rhs->persistent_fds;
-	if (lhs->ephemeral_fds > rhs->ephemeral_fds) {
-		expr->ephemeral_fds = lhs->ephemeral_fds;
-	} else {
-		expr->ephemeral_fds = rhs->ephemeral_fds;
-	}
-
-	return expr;
-}
-
 /**
  * Color use flags.
  */
@@ -343,6 +299,58 @@ static bool parse_expr_warning(const struct bfs_parser *parser, const struct bfs
 	return ret;
 }
 
+/**
+ * Allocate a new expression.
+ */
+static struct bfs_expr *parse_new_expr(const struct bfs_parser *parser, bfs_eval_fn *eval_fn, size_t argc, char **argv) {
+	struct bfs_expr *expr = bfs_expr_new(parser->ctx, eval_fn, argc, argv);
+	if (!expr) {
+		parse_perror(parser, "bfs_expr_new()");
+	}
+	return expr;
+}
+
+/**
+ * Create a new unary expression.
+ */
+static struct bfs_expr *new_unary_expr(const struct bfs_parser *parser, bfs_eval_fn *eval_fn, struct bfs_expr *rhs, char **argv) {
+	struct bfs_expr *expr = parse_new_expr(parser, eval_fn, 1, argv);
+	if (!expr) {
+		return NULL;
+	}
+
+	expr->lhs = NULL;
+	expr->rhs = rhs;
+	bfs_assert(bfs_expr_is_parent(expr));
+
+	expr->persistent_fds = rhs->persistent_fds;
+	expr->ephemeral_fds = rhs->ephemeral_fds;
+	return expr;
+}
+
+/**
+ * Create a new binary expression.
+ */
+static struct bfs_expr *new_binary_expr(const struct bfs_parser *parser, bfs_eval_fn *eval_fn, struct bfs_expr *lhs, struct bfs_expr *rhs, char **argv) {
+	struct bfs_expr *expr = parse_new_expr(parser, eval_fn, 1, argv);
+	if (!expr) {
+		return NULL;
+	}
+
+	expr->lhs = lhs;
+	expr->rhs = rhs;
+	bfs_assert(bfs_expr_is_parent(expr));
+
+	expr->persistent_fds = lhs->persistent_fds + rhs->persistent_fds;
+	if (lhs->ephemeral_fds > rhs->ephemeral_fds) {
+		expr->ephemeral_fds = lhs->ephemeral_fds;
+	} else {
+		expr->ephemeral_fds = rhs->ephemeral_fds;
+	}
+
+	return expr;
+}
+
 /**
  * Fill in a "-print"-type expression.
  */
@@ -645,7 +653,7 @@ static bool looks_like_icmp(const char *str) {
  */
 static struct bfs_expr *parse_flag(struct bfs_parser *parser, size_t argc) {
 	char **argv = parser_advance(parser, T_FLAG, argc);
-	return bfs_expr_new(eval_true, argc, argv);
+	return parse_new_expr(parser, eval_true, argc, argv);
 }
 
 /**
@@ -674,7 +682,7 @@ static struct bfs_expr *parse_unary_flag(struct bfs_parser *parser) {
  */
 static struct bfs_expr *parse_option(struct bfs_parser *parser, size_t argc) {
 	char **argv = parser_advance(parser, T_OPTION, argc);
-	return bfs_expr_new(eval_true, argc, argv);
+	return parse_new_expr(parser, eval_true, argc, argv);
 }
 
 /**
@@ -703,7 +711,7 @@ static struct bfs_expr *parse_unary_option(struct bfs_parser *parser) {
  */
 static struct bfs_expr *parse_test(struct bfs_parser *parser, bfs_eval_fn *eval_fn, size_t argc) {
 	char **argv = parser_advance(parser, T_TEST, argc);
-	return bfs_expr_new(eval_fn, argc, argv);
+	return parse_new_expr(parser, eval_fn, argc, argv);
 }
 
 /**
@@ -742,7 +750,7 @@ static struct bfs_expr *parse_action(struct bfs_parser *parser, bfs_eval_fn *eva
 		parser->implicit_print = false;
 	}
 
-	return bfs_expr_new(eval_fn, argc, argv);
+	return parse_new_expr(parser, eval_fn, argc, argv);
 }
 
 /**
@@ -771,7 +779,7 @@ static struct bfs_expr *parse_unary_action(struct bfs_parser *parser, bfs_eval_f
  */
 static int parse_exclude(struct bfs_parser *parser, struct bfs_expr *expr) {
 	struct bfs_ctx *ctx = parser->ctx;
-	ctx->exclude = new_binary_expr(eval_or, ctx->exclude, expr, &fake_or_arg);
+	ctx->exclude = new_binary_expr(parser, eval_or, ctx->exclude, expr, &fake_or_arg);
 	if (ctx->exclude) {
 		return 0;
 	} else {
@@ -789,7 +797,6 @@ static struct bfs_expr *parse_test_icmp(struct bfs_parser *parser, bfs_eval_fn *
 	}
 
 	if (!parse_icmp(parser, expr, 0)) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -848,7 +855,6 @@ static struct bfs_expr *parse_debug(struct bfs_parser *parser, int arg1, int arg
 		if (parse_debug_flag(flag, len, "help")) {
 			debug_help(ctx->cout);
 			parser->just_info = true;
-			bfs_expr_free(expr);
 			return NULL;
 		} else if (parse_debug_flag(flag, len, "all")) {
 			ctx->debug = DEBUG_ALL;
@@ -896,7 +902,6 @@ static struct bfs_expr *parse_optlevel(struct bfs_parser *parser, int arg1, int
 	if (strcmp(expr->argv[0], "-Ofast") == 0) {
 		*optlevel = 4;
 	} else if (!parse_int(parser, expr->argv, expr->argv[0] + 2, optlevel, IF_INT | IF_UNSIGNED)) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -963,16 +968,12 @@ static struct bfs_expr *parse_newer(struct bfs_parser *parser, int field, int ar
 
 	struct bfs_stat sb;
 	if (stat_arg(parser, &expr->argv[1], &sb) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	expr->reftime = sb.mtime;
 	expr->stat_field = field;
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1004,7 +1005,7 @@ static struct bfs_expr *parse_time(struct bfs_parser *parser, int field, int arg
 
 	const char *tail = parse_icmp(parser, expr, IF_PARTIAL_OK);
 	if (!tail) {
-		goto fail;
+		return NULL;
 	}
 
 	if (!*tail) {
@@ -1033,7 +1034,7 @@ static struct bfs_expr *parse_time(struct bfs_parser *parser, int field, int arg
 			break;
 		default:
 			parse_expr_error(parser, expr, "Unknown time unit ${bld}%c${rs}.\n", *tail);
-			goto fail;
+			return NULL;
 		}
 
 		expr->num += time;
@@ -1044,20 +1045,16 @@ static struct bfs_expr *parse_time(struct bfs_parser *parser, int field, int arg
 
 		tail = parse_int(parser, &expr->argv[1], tail, &time, IF_PARTIAL_OK | IF_LONG_LONG | IF_UNSIGNED);
 		if (!tail) {
-			goto fail;
+			return NULL;
 		}
 		if (!*tail) {
 			parse_expr_error(parser, expr, "Missing time unit.\n");
-			goto fail;
+			return NULL;
 		}
 	}
 
 	expr->time_unit = BFS_SECONDS;
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1087,7 +1084,6 @@ static struct bfs_expr *parse_color(struct bfs_parser *parser, int color, int ar
 	if (color) {
 		if (!colors) {
 			parse_expr_error(parser, expr, "Error parsing $$LS_COLORS: %s.\n", xstrerror(ctx->colors_error));
-			bfs_expr_free(expr);
 			return NULL;
 		}
 
@@ -1182,7 +1178,6 @@ static struct bfs_expr *parse_depth_limit(struct bfs_parser *parser, int is_min,
 	int *depth = is_min ? &ctx->mindepth : &ctx->maxdepth;
 	char **arg = &expr->argv[1];
 	if (!parse_int(parser, arg, *arg, depth, IF_INT | IF_UNSIGNED)) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -1235,7 +1230,7 @@ static struct bfs_expr *parse_exec(struct bfs_parser *parser, int flags, int arg
 				} else {
 					parse_perror(parser, "strndup()");
 				}
-				goto fail;
+				return NULL;
 			}
 
 			path = strchr(path, ':');
@@ -1257,10 +1252,6 @@ static struct bfs_expr *parse_exec(struct bfs_parser *parser, int flags, int arg
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1292,7 +1283,6 @@ static struct bfs_expr *parse_f(struct bfs_parser *parser, int arg1, int arg2) {
 	}
 
 	if (parse_root(parser, expr->argv[1]) != 0) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -1318,7 +1308,7 @@ static struct bfs_expr *parse_files0_from(struct bfs_parser *parser, int arg1, i
 	}
 	if (!file) {
 		parse_expr_error(parser, expr, "%m.\n");
-		goto fail;
+		return NULL;
 	}
 
 	while (true) {
@@ -1348,10 +1338,9 @@ static struct bfs_expr *parse_files0_from(struct bfs_parser *parser, int arg1, i
 	return expr;
 
 fail:
-	if (file && file != stdin) {
+	if (file != stdin) {
 		fclose(file);
 	}
-	bfs_expr_free(expr);
 	return NULL;
 }
 
@@ -1385,7 +1374,6 @@ static struct bfs_expr *parse_flags(struct bfs_parser *parser, int arg1, int arg
 		} else {
 			parse_expr_error(parser, expr, "Invalid flags.\n");
 		}
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -1398,18 +1386,14 @@ static struct bfs_expr *parse_flags(struct bfs_parser *parser, int arg1, int arg
 static struct bfs_expr *parse_fls(struct bfs_parser *parser, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(parser, eval_fls);
 	if (!expr) {
-		goto fail;
+		return NULL;
 	}
 
 	if (expr_open(parser, expr, expr->argv[1]) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1417,16 +1401,15 @@ fail:
  */
 static struct bfs_expr *parse_fprint(struct bfs_parser *parser, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(parser, eval_fprint);
-	if (expr) {
-		if (expr_open(parser, expr, expr->argv[1]) != 0) {
-			goto fail;
-		}
+	if (!expr) {
+		return NULL;
 	}
-	return expr;
 
-fail:
-	bfs_expr_free(expr);
-	return NULL;
+	if (expr_open(parser, expr, expr->argv[1]) != 0) {
+		return NULL;
+	}
+
+	return expr;
 }
 
 /**
@@ -1434,16 +1417,15 @@ fail:
  */
 static struct bfs_expr *parse_fprint0(struct bfs_parser *parser, int arg1, int arg2) {
 	struct bfs_expr *expr = parse_unary_action(parser, eval_fprint0);
-	if (expr) {
-		if (expr_open(parser, expr, expr->argv[1]) != 0) {
-			goto fail;
-		}
+	if (!expr) {
+		return NULL;
 	}
-	return expr;
 
-fail:
-	bfs_expr_free(expr);
-	return NULL;
+	if (expr_open(parser, expr, expr->argv[1]) != 0) {
+		return NULL;
+	}
+
+	return expr;
 }
 
 /**
@@ -1470,18 +1452,14 @@ static struct bfs_expr *parse_fprintf(struct bfs_parser *parser, int arg1, int a
 	}
 
 	if (expr_open(parser, expr, file) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	if (bfs_printf_parse(parser->ctx, expr, format) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1495,7 +1473,6 @@ static struct bfs_expr *parse_fstype(struct bfs_parser *parser, int arg1, int ar
 
 	if (!bfs_ctx_mtab(parser->ctx)) {
 		parse_expr_error(parser, expr, "Couldn't parse the mount table: %m.\n");
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -1517,21 +1494,17 @@ static struct bfs_expr *parse_group(struct bfs_parser *parser, int arg1, int arg
 		expr->int_cmp = BFS_INT_EQUAL;
 	} else if (looks_like_icmp(expr->argv[1])) {
 		if (!parse_icmp(parser, expr, 0)) {
-			goto fail;
+			return NULL;
 		}
 	} else if (errno) {
 		parse_expr_error(parser, expr, "%m.\n");
-		goto fail;
+		return NULL;
 	} else {
 		parse_expr_error(parser, expr, "No such group.\n");
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1564,21 +1537,17 @@ static struct bfs_expr *parse_user(struct bfs_parser *parser, int arg1, int arg2
 		expr->int_cmp = BFS_INT_EQUAL;
 	} else if (looks_like_icmp(expr->argv[1])) {
 		if (!parse_icmp(parser, expr, 0)) {
-			goto fail;
+			return NULL;
 		}
 	} else if (errno) {
 		parse_expr_error(parser, expr, "%m.\n");
-		goto fail;
+		return NULL;
 	} else {
 		parse_expr_error(parser, expr, "No such user.\n");
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1614,13 +1583,11 @@ static struct bfs_expr *parse_jobs(struct bfs_parser *parser, int arg1, int arg2
 
 	unsigned int n;
 	if (!parse_int(parser, expr->argv, expr->argv[0] + 2, &n, IF_INT | IF_UNSIGNED)) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
 	if (n == 0) {
 		parse_expr_error(parser, expr, "${bld}0${rs} is not enough threads.\n");
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -1680,7 +1647,6 @@ static struct bfs_expr *parse_fnmatch(const struct bfs_parser *parser, struct bf
 		expr->fnm_flags = FNM_CASEFOLD;
 #else
 		parse_expr_error(parser, expr, "Missing platform support.\n");
-		bfs_expr_free(expr);
 		return NULL;
 #endif
 	} else {
@@ -1811,7 +1777,7 @@ static struct bfs_expr *parse_newerxy(struct bfs_parser *parser, int arg1, int a
 
 	struct bfs_expr *expr = parse_unary_test(parser, eval_newer);
 	if (!expr) {
-		goto fail;
+		return NULL;
 	}
 
 	expr->stat_field = parse_newerxy_field(arg[6]);
@@ -1819,12 +1785,12 @@ static struct bfs_expr *parse_newerxy(struct bfs_parser *parser, int arg1, int a
 		parse_expr_error(parser, expr,
 			"For ${blu}-newer${bld}XY${rs}, ${bld}X${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, or ${bld}B${rs}, not ${err}%c${rs}.\n",
 			arg[6]);
-		goto fail;
+		return NULL;
 	}
 
 	if (arg[7] == 't') {
 		if (parse_reftime(parser, expr) != 0) {
-			goto fail;
+			return NULL;
 		}
 	} else {
 		enum bfs_stat_field field = parse_newerxy_field(arg[7]);
@@ -1832,28 +1798,24 @@ static struct bfs_expr *parse_newerxy(struct bfs_parser *parser, int arg1, int a
 			parse_expr_error(parser, expr,
 				"For ${blu}-newer${bld}XY${rs}, ${bld}Y${rs} should be ${bld}a${rs}, ${bld}c${rs}, ${bld}m${rs}, ${bld}B${rs}, or ${bld}t${rs}, not ${err}%c${rs}.\n",
 				arg[7]);
-			goto fail;
+			return NULL;
 		}
 
 		struct bfs_stat sb;
 		if (stat_arg(parser, &expr->argv[1], &sb) != 0) {
-			goto fail;
+			return NULL;
 		}
 
 		const struct timespec *reftime = bfs_stat_time(&sb, field);
 		if (!reftime) {
 			parse_expr_error(parser, expr, "Couldn't get file %s.\n", bfs_stat_field_name(field));
-			goto fail;
+			return NULL;
 		}
 
 		expr->reftime = *reftime;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -1872,7 +1834,7 @@ static struct bfs_expr *parse_nogroup(struct bfs_parser *parser, int arg1, int a
  * Parse -nohidden.
  */
 static struct bfs_expr *parse_nohidden(struct bfs_parser *parser, int arg1, int arg2) {
-	struct bfs_expr *hidden = bfs_expr_new(eval_hidden, 1, &fake_hidden_arg);
+	struct bfs_expr *hidden = parse_new_expr(parser, eval_hidden, 1, &fake_hidden_arg);
 	if (!hidden) {
 		return NULL;
 	}
@@ -2158,14 +2120,10 @@ static struct bfs_expr *parse_perm(struct bfs_parser *parser, int field, int arg
 	}
 
 	if (parse_mode(parser, mode, expr) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -2202,7 +2160,6 @@ static struct bfs_expr *parse_printf(struct bfs_parser *parser, int arg1, int ar
 	init_print_expr(parser, expr);
 
 	if (bfs_printf_parse(parser->ctx, expr, expr->argv[1]) != 0) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -2241,31 +2198,26 @@ static struct bfs_expr *parse_quit(struct bfs_parser *parser, int arg1, int arg2
 static struct bfs_expr *parse_regex(struct bfs_parser *parser, int flags, int arg2) {
 	struct bfs_expr *expr = parse_unary_test(parser, eval_regex);
 	if (!expr) {
-		goto fail;
+		return NULL;
 	}
 
 	if (bfs_regcomp(&expr->regex, expr->argv[1], parser->regex_type, flags) != 0) {
-		if (!expr->regex) {
+		if (expr->regex) {
+			char *str = bfs_regerror(expr->regex);
+			if (str) {
+				parse_expr_error(parser, expr, "%s.\n", str);
+				free(str);
+			} else {
+				parse_perror(parser, "bfs_regerror()");
+			}
+		} else {
 			parse_perror(parser, "bfs_regcomp()");
-			goto fail;
 		}
 
-		char *str = bfs_regerror(expr->regex);
-		if (!str) {
-			parse_perror(parser, "bfs_regerror()");
-			goto fail;
-		}
-
-		parse_expr_error(parser, expr, "%s.\n", str);
-		free(str);
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -2324,8 +2276,6 @@ list_types:
 	cfprintf(cfile, "  ${bld}grep${rs}:           Like ${grn}grep${rs}\n");
 #endif
 	cfprintf(cfile, "  ${bld}sed${rs}:            Like ${grn}sed${rs} (same as ${bld}posix-basic${rs})\n");
-
-	bfs_expr_free(expr);
 	return NULL;
 }
 
@@ -2348,7 +2298,6 @@ static struct bfs_expr *parse_samefile(struct bfs_parser *parser, int arg1, int
 
 	struct bfs_stat sb;
 	if (stat_arg(parser, &expr->argv[1], &sb) != 0) {
-		bfs_expr_free(expr);
 		return NULL;
 	}
 
@@ -2396,8 +2345,6 @@ list_strategies:
 	cfprintf(cfile, "  ${bld}dfs${rs}: depth-first search\n");
 	cfprintf(cfile, "  ${bld}ids${rs}: iterative deepening search\n");
 	cfprintf(cfile, "  ${bld}eds${rs}: exponential deepening search\n");
-
-	bfs_expr_free(expr);
 	return NULL;
 }
 
@@ -2411,15 +2358,11 @@ static struct bfs_expr *parse_since(struct bfs_parser *parser, int field, int ar
 	}
 
 	if (parse_reftime(parser, expr) != 0) {
-		goto fail;
+		return NULL;
 	}
 
 	expr->stat_field = field;
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -2433,7 +2376,7 @@ static struct bfs_expr *parse_size(struct bfs_parser *parser, int arg1, int arg2
 
 	const char *unit = parse_icmp(parser, expr, IF_PARTIAL_OK);
 	if (!unit) {
-		goto fail;
+		return NULL;
 	}
 
 	if (strlen(unit) > 1) {
@@ -2468,16 +2411,12 @@ static struct bfs_expr *parse_size(struct bfs_parser *parser, int arg1, int arg2
 		break;
 
 	default:
-		goto bad_unit;
+	bad_unit:
+		parse_expr_error(parser, expr, "Expected a size unit (one of ${bld}cwbkMGTP${rs}); found ${err}%pq${rs}.\n", unit);
+		return NULL;
 	}
 
 	return expr;
-
-bad_unit:
-	parse_expr_error(parser, expr, "Expected a size unit (one of ${bld}cwbkMGTP${rs}); found ${err}%pq${rs}.\n", unit);
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -2543,11 +2482,11 @@ static struct bfs_expr *parse_type(struct bfs_parser *parser, int x, int arg2) {
 
 		case '\0':
 			parse_expr_error(parser, expr, "Expected a type flag.\n");
-			goto fail;
+			return NULL;
 
 		default:
 			parse_expr_error(parser, expr, "Unknown type flag ${err}%c${rs}; expected one of [${bld}bcdpflsD${rs}].\n", *c);
-			goto fail;
+			return NULL;
 		}
 
 		++c;
@@ -2558,15 +2497,11 @@ static struct bfs_expr *parse_type(struct bfs_parser *parser, int x, int arg2) {
 			continue;
 		} else {
 			parse_expr_error(parser, expr, "Types must be comma-separated.\n");
-			goto fail;
+			return NULL;
 		}
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 /**
@@ -3244,14 +3179,12 @@ static struct bfs_expr *parse_factor(struct bfs_parser *parser) {
 		}
 
 		if (skip_paths(parser) != 0) {
-			bfs_expr_free(expr);
 			return NULL;
 		}
 
 		arg = parser->argv[0];
 		if (!arg || strcmp(arg, ")") != 0) {
 			parse_argv_error(parser, parser->last_arg, 1, "Expected a ${red})${rs}.\n");
-			bfs_expr_free(expr);
 			return NULL;
 		}
 
@@ -3277,7 +3210,7 @@ static struct bfs_expr *parse_factor(struct bfs_parser *parser) {
 			return NULL;
 		}
 
-		return bfs_expr_new(eval_true, parser->argv - argv, argv);
+		return parse_new_expr(parser, eval_true, parser->argv - argv, argv);
 	} else if (strcmp(arg, "!") == 0 || strcmp(arg, "-not") == 0) {
 		char **argv = parser_advance(parser, T_OPERATOR, 1);
 
@@ -3286,7 +3219,7 @@ static struct bfs_expr *parse_factor(struct bfs_parser *parser) {
 			return NULL;
 		}
 
-		return new_unary_expr(eval_not, factor, argv);
+		return new_unary_expr(parser, eval_not, factor, argv);
 	} else {
 		return parse_primary(parser);
 	}
@@ -3303,7 +3236,6 @@ static struct bfs_expr *parse_term(struct bfs_parser *parser) {
 
 	while (term) {
 		if (skip_paths(parser) != 0) {
-			bfs_expr_free(term);
 			return NULL;
 		}
 
@@ -3326,11 +3258,10 @@ static struct bfs_expr *parse_term(struct bfs_parser *parser) {
 		struct bfs_expr *lhs = term;
 		struct bfs_expr *rhs = parse_factor(parser);
 		if (!rhs) {
-			bfs_expr_free(lhs);
 			return NULL;
 		}
 
-		term = new_binary_expr(eval_and, lhs, rhs, argv);
+		term = new_binary_expr(parser, eval_and, lhs, rhs, argv);
 	}
 
 	return term;
@@ -3346,7 +3277,6 @@ static struct bfs_expr *parse_clause(struct bfs_parser *parser) {
 
 	while (clause) {
 		if (skip_paths(parser) != 0) {
-			bfs_expr_free(clause);
 			return NULL;
 		}
 
@@ -3364,11 +3294,10 @@ static struct bfs_expr *parse_clause(struct bfs_parser *parser) {
 		struct bfs_expr *lhs = clause;
 		struct bfs_expr *rhs = parse_term(parser);
 		if (!rhs) {
-			bfs_expr_free(lhs);
 			return NULL;
 		}
 
-		clause = new_binary_expr(eval_or, lhs, rhs, argv);
+		clause = new_binary_expr(parser, eval_or, lhs, rhs, argv);
 	}
 
 	return clause;
@@ -3383,7 +3312,6 @@ static struct bfs_expr *parse_expr(struct bfs_parser *parser) {
 
 	while (expr) {
 		if (skip_paths(parser) != 0) {
-			bfs_expr_free(expr);
 			return NULL;
 		}
 
@@ -3401,11 +3329,10 @@ static struct bfs_expr *parse_expr(struct bfs_parser *parser) {
 		struct bfs_expr *lhs = expr;
 		struct bfs_expr *rhs = parse_clause(parser);
 		if (!rhs) {
-			bfs_expr_free(lhs);
 			return NULL;
 		}
 
-		expr = new_binary_expr(eval_comma, lhs, rhs, argv);
+		expr = new_binary_expr(parser, eval_comma, lhs, rhs, argv);
 	}
 
 	return expr;
@@ -3423,7 +3350,7 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
 	if (parser->argv[0]) {
 		expr = parse_expr(parser);
 	} else {
-		expr = bfs_expr_new(eval_true, 1, &fake_true_arg);
+		expr = parse_new_expr(parser, eval_true, 1, &fake_true_arg);
 	}
 	if (!expr) {
 		return NULL;
@@ -3431,19 +3358,19 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
 
 	if (parser->argv[0]) {
 		parse_error(parser, "Unexpected argument.\n");
-		goto fail;
+		return NULL;
 	}
 
 	if (parser->implicit_print) {
-		struct bfs_expr *print = bfs_expr_new(eval_fprint, 1, &fake_print_arg);
+		struct bfs_expr *print = parse_new_expr(parser, eval_fprint, 1, &fake_print_arg);
 		if (!print) {
-			goto fail;
+			return NULL;
 		}
 		init_print_expr(parser, print);
 
-		expr = new_binary_expr(eval_and, expr, print, &fake_and_arg);
+		expr = new_binary_expr(parser, eval_and, expr, print, &fake_and_arg);
 		if (!expr) {
-			goto fail;
+			return NULL;
 		}
 	}
 
@@ -3461,7 +3388,7 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
 		if (parser->interactive) {
 			bfs_warning(parser->ctx, "Do you want to continue? ");
 			if (ynprompt() == 0) {
-				goto fail;
+				return NULL;
 			}
 		}
 
@@ -3472,14 +3399,10 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
 		parse_conflict_error(parser, parser->ok_expr->argv, parser->ok_expr->argc, parser->files0_stdin_arg, 2,
 			"${blu}%s${rs} conflicts with ${blu}%s${rs} ${bld}%s${rs}.\n",
 			parser->ok_expr->argv[0], parser->files0_stdin_arg[0], parser->files0_stdin_arg[1]);
-		goto fail;
+		return NULL;
 	}
 
 	return expr;
-
-fail:
-	bfs_expr_free(expr);
-	return NULL;
 }
 
 static const char *bftw_strategy_name(enum bftw_strategy strategy) {
@@ -3637,7 +3560,7 @@ static void dump_costs(const struct bfs_ctx *ctx) {
 struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 	struct bfs_ctx *ctx = bfs_ctx_new();
 	if (!ctx) {
-		perror("bfs_new_ctx()");
+		perror("bfs_ctx_new()");
 		goto fail;
 	}
 
@@ -3715,7 +3638,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 		.now = ctx->now,
 	};
 
-	ctx->exclude = bfs_expr_new(eval_false, 1, &fake_false_arg);
+	ctx->exclude = parse_new_expr(&parser, eval_false, 1, &fake_false_arg);
 	if (!ctx->exclude) {
 		goto fail;
 	}
@@ -3734,6 +3657,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 	}
 
 	if (bfs_optimize(ctx) != 0) {
+		bfs_perror(ctx, "bfs_optimize()");
 		goto fail;
 	}
 
-- 
cgit v1.2.3


From 4a36bb92a5bbdc41965a6d2c6eae6cdca5983474 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sun, 7 Jan 2024 12:19:17 -0500
Subject: expr: Make expressions variadic

Rather than only unary/binary expressions, we now support an arbitrary
number of children.  The optimizer has been re-written almost completely
and now supports optimal reordering of longer expression chains, rather
than just arm-swapping.

Fixes #85.
---
 src/color.c |   39 +-
 src/ctx.c   |    2 +-
 src/diag.c  |    5 +-
 src/eval.c  |   55 +-
 src/expr.c  |   37 +-
 src/expr.h  |   28 +-
 src/opt.c   | 2468 +++++++++++++++++++++++++++++++++++++++--------------------
 src/parse.c |   73 +-
 8 files changed, 1768 insertions(+), 939 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/color.c b/src/color.c
index 5247cbf..1f10c04 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1109,7 +1109,11 @@ attr(printf(2, 3))
 static int cbuff(CFILE *cfile, const char *format, ...);
 
 /** Dump a parsed expression tree, for debugging. */
-static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
+static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose, int depth) {
+	if (depth >= 2) {
+		return dstrcat(&cfile->buffer, "(...)");
+	}
+
 	if (!expr) {
 		return dstrcat(&cfile->buffer, "(null)");
 	}
@@ -1118,13 +1122,7 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 		return -1;
 	}
 
-	const struct bfs_expr *lhs = NULL;
-	const struct bfs_expr *rhs = NULL;
-
 	if (bfs_expr_is_parent(expr)) {
-		lhs = expr->lhs;
-		rhs = expr->rhs;
-
 		if (cbuff(cfile, "${red}%pq${rs}", expr->argv[0]) < 0) {
 			return -1;
 		}
@@ -1152,21 +1150,20 @@ static int print_expr(CFILE *cfile, const struct bfs_expr *expr, bool verbose) {
 		}
 	}
 
-	if (lhs) {
-		if (dstrcat(&cfile->buffer, " ") != 0) {
-			return -1;
-		}
-		if (print_expr(cfile, lhs, verbose) != 0) {
-			return -1;
-		}
-	}
-
-	if (rhs) {
+	int count = 0;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
 		if (dstrcat(&cfile->buffer, " ") != 0) {
 			return -1;
 		}
-		if (print_expr(cfile, rhs, verbose) != 0) {
-			return -1;
+		if (++count >= 3) {
+			if (dstrcat(&cfile->buffer, "...") != 0) {
+				return -1;
+			}
+			break;
+		} else {
+			if (print_expr(cfile, child, verbose, depth + 1) != 0) {
+				return -1;
+			}
 		}
 	}
 
@@ -1276,12 +1273,12 @@ static int cvbuff(CFILE *cfile, const char *format, va_list args) {
 					break;
 
 				case 'e':
-					if (print_expr(cfile, va_arg(args, const struct bfs_expr *), false) != 0) {
+					if (print_expr(cfile, va_arg(args, const struct bfs_expr *), false, 0) != 0) {
 						return -1;
 					}
 					break;
 				case 'E':
-					if (print_expr(cfile, va_arg(args, const struct bfs_expr *), true) != 0) {
+					if (print_expr(cfile, va_arg(args, const struct bfs_expr *), true, 0) != 0) {
 						return -1;
 					}
 					break;
diff --git a/src/ctx.c b/src/ctx.c
index a3c5140..1f3e72e 100644
--- a/src/ctx.c
+++ b/src/ctx.c
@@ -241,7 +241,7 @@ int bfs_ctx_free(struct bfs_ctx *ctx) {
 
 		free_colors(ctx->colors);
 
-		for_slist (struct bfs_expr, expr, &ctx->expr_list) {
+		for_slist (struct bfs_expr, expr, &ctx->expr_list, freelist) {
 			bfs_expr_clear(expr);
 		}
 		arena_destroy(&ctx->expr_arena);
diff --git a/src/diag.c b/src/diag.c
index bf2343d..efa7ebd 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -158,9 +158,8 @@ static bool highlight_expr_recursive(const struct bfs_ctx *ctx, const struct bfs
 		}
 	}
 
-	if (bfs_expr_is_parent(expr)) {
-		ret |= highlight_expr_recursive(ctx, expr->lhs, args);
-		ret |= highlight_expr_recursive(ctx, expr->rhs, args);
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		ret |= highlight_expr_recursive(ctx, child, args);
 	}
 
 	return ret;
diff --git a/src/eval.c b/src/eval.c
index 372fcf5..49c4aff 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -372,11 +372,10 @@ static int eval_exec_finish(const struct bfs_expr *expr, const struct bfs_ctx *c
 			}
 			ret = -1;
 		}
-	} else if (bfs_expr_is_parent(expr)) {
-		if (expr->lhs && eval_exec_finish(expr->lhs, ctx) != 0) {
-			ret = -1;
-		}
-		if (expr->rhs && eval_exec_finish(expr->rhs, ctx) != 0) {
+	}
+
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (eval_exec_finish(child, ctx) != 0) {
 			ret = -1;
 		}
 	}
@@ -1045,50 +1044,48 @@ static bool eval_expr(struct bfs_expr *expr, struct bfs_eval *state) {
  * Evaluate a negation.
  */
 bool eval_not(const struct bfs_expr *expr, struct bfs_eval *state) {
-	return !eval_expr(expr->rhs, state);
+	return !eval_expr(bfs_expr_children(expr), state);
 }
 
 /**
  * Evaluate a conjunction.
  */
 bool eval_and(const struct bfs_expr *expr, struct bfs_eval *state) {
-	if (!eval_expr(expr->lhs, state)) {
-		return false;
-	}
-
-	if (state->quit) {
-		return false;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (!eval_expr(child, state) || state->quit) {
+			return false;
+		}
 	}
 
-	return eval_expr(expr->rhs, state);
+	return true;
 }
 
 /**
  * Evaluate a disjunction.
  */
 bool eval_or(const struct bfs_expr *expr, struct bfs_eval *state) {
-	if (eval_expr(expr->lhs, state)) {
-		return true;
-	}
-
-	if (state->quit) {
-		return false;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (eval_expr(child, state) || state->quit) {
+			return true;
+		}
 	}
 
-	return eval_expr(expr->rhs, state);
+	return false;
 }
 
 /**
  * Evaluate the comma operator.
  */
 bool eval_comma(const struct bfs_expr *expr, struct bfs_eval *state) {
-	eval_expr(expr->lhs, state);
-
-	if (state->quit) {
-		return false;
+	bool ret;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		ret = eval_expr(child, state);
+		if (state->quit) {
+			break;
+		}
 	}
 
-	return eval_expr(expr->rhs, state);
+	return ret;
 }
 
 /** Update the status bar. */
@@ -1571,12 +1568,8 @@ static bool eval_must_buffer(const struct bfs_expr *expr) {
 		return true;
 	}
 
-	if (bfs_expr_is_parent(expr)) {
-		if (expr->lhs && eval_must_buffer(expr->lhs)) {
-			return true;
-		}
-
-		if (expr->rhs && eval_must_buffer(expr->rhs)) {
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (eval_must_buffer(child)) {
 			return true;
 		}
 	}
diff --git a/src/expr.c b/src/expr.c
index 2002fc7..3e0033f 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -23,7 +23,12 @@ struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t
 	expr->argc = argc;
 	expr->argv = argv;
 	expr->probability = 0.5;
-	SLIST_PREPEND(&ctx->expr_list, expr);
+	SLIST_PREPEND(&ctx->expr_list, expr, freelist);
+
+	if (bfs_expr_is_parent(expr)) {
+		SLIST_INIT(&expr->children);
+	}
+
 	return expr;
 }
 
@@ -34,6 +39,36 @@ bool bfs_expr_is_parent(const struct bfs_expr *expr) {
 		|| expr->eval_fn == eval_comma;
 }
 
+struct bfs_expr *bfs_expr_children(const struct bfs_expr *expr) {
+	if (bfs_expr_is_parent(expr)) {
+		return expr->children.head;
+	} else {
+		return NULL;
+	}
+}
+
+void bfs_expr_append(struct bfs_expr *expr, struct bfs_expr *child) {
+	bfs_assert(bfs_expr_is_parent(expr));
+
+	SLIST_APPEND(&expr->children, child);
+
+	if (!child->pure) {
+		expr->pure = false;
+	}
+
+	expr->persistent_fds += child->persistent_fds;
+	if (expr->ephemeral_fds < child->ephemeral_fds) {
+		expr->ephemeral_fds = child->ephemeral_fds;
+	}
+}
+
+void bfs_expr_extend(struct bfs_expr *expr, struct bfs_exprs *children) {
+	while (!SLIST_EMPTY(children)) {
+		struct bfs_expr *child = SLIST_POP(children);
+		bfs_expr_append(expr, child);
+	}
+}
+
 bool bfs_expr_never_returns(const struct bfs_expr *expr) {
 	// Expressions that never return are vacuously both always true and always false
 	return expr->always_true && expr->always_false;
diff --git a/src/expr.h b/src/expr.h
index 290f1f8..4d607a4 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -86,8 +86,10 @@ struct bfs_exprs {
  * A command line expression.
  */
 struct bfs_expr {
-	/** The next allocated expression. */
+	/** This expression's next sibling, if any. */
 	struct bfs_expr *next;
+	/** The next allocated expression. */
+	struct { struct bfs_expr *next; } freelist;
 
 	/** The function that evaluates this expression. */
 	bfs_eval_fn *eval_fn;
@@ -123,12 +125,7 @@ struct bfs_expr {
 	/** Auxilliary data for the evaluation function. */
 	union {
 		/** Child expressions. */
-		struct {
-			/** The left hand side of the expression. */
-			struct bfs_expr *lhs;
-			/** The right hand side of the expression. */
-			struct bfs_expr *rhs;
-		};
+		struct bfs_exprs children;
 
 		/** Integer comparisons. */
 		struct {
@@ -218,10 +215,25 @@ struct bfs_ctx;
 struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval, size_t argc, char **argv);
 
 /**
- * @return Whether the expression has child expressions.
+ * @return Whether this type of expression has children.
  */
 bool bfs_expr_is_parent(const struct bfs_expr *expr);
 
+/**
+ * @return The first child of this expression, or NULL if it has none.
+ */
+struct bfs_expr *bfs_expr_children(const struct bfs_expr *expr);
+
+/**
+ * Add a child to an expression.
+ */
+void bfs_expr_append(struct bfs_expr *expr, struct bfs_expr *child);
+
+/**
+ * Add a list of children to an expression.
+ */
+void bfs_expr_extend(struct bfs_expr *expr, struct bfs_exprs *children);
+
 /**
  * @return Whether expr is known to always quit.
  */
diff --git a/src/opt.c b/src/opt.c
index 1dc985a..7203c61 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -21,11 +21,12 @@
  * -bar is likely to return false.
  *
  * -O4/-Ofast: aggressive optimizations that may affect correctness in corner
- * cases.  The main effect is to use impure to determine if any side-effects are
- * reachable at all, and skipping the traversal if not.
+ * cases.  The main effect is to use opt->impure to determine if any side-
+ * effects are reachable at all, skipping the traversal if not.
  */
 
 #include "opt.h"
+#include "bit.h"
 #include "color.h"
 #include "config.h"
 #include "ctx.h"
@@ -33,6 +34,7 @@
 #include "eval.h"
 #include "exec.h"
 #include "expr.h"
+#include "list.h"
 #include "pwcache.h"
 #include <errno.h>
 #include <limits.h>
@@ -41,9 +43,9 @@
 #include <string.h>
 #include <unistd.h>
 
-static char *fake_and_arg = "-a";
-static char *fake_or_arg = "-o";
-static char *fake_not_arg = "!";
+static char *fake_and_arg = "-and";
+static char *fake_or_arg = "-or";
+static char *fake_not_arg = "-not";
 
 /**
  * The data flow domain for predicates.
@@ -69,6 +71,70 @@ static void pred_join(enum df_pred *dest, enum df_pred src) {
 	*dest |= src;
 }
 
+/**
+ * Types of predicates we track.
+ */
+enum pred_type {
+	/** -readable */
+	READABLE_PRED,
+	/** -writable */
+	WRITABLE_PRED,
+	/** -executable */
+	EXECUTABLE_PRED,
+	/** -acl */
+	ACL_PRED,
+	/** -capable */
+	CAPABLE_PRED,
+	/** -empty */
+	EMPTY_PRED,
+	/** -hidden */
+	HIDDEN_PRED,
+	/** -nogroup */
+	NOGROUP_PRED,
+	/** -nouser */
+	NOUSER_PRED,
+	/** -sparse */
+	SPARSE_PRED,
+	/** -xattr */
+	XATTR_PRED,
+	/** The number of pred_types. */
+	PRED_TYPES,
+};
+
+/** Get the name of a predicate type. */
+static const char *pred_type_name(enum pred_type type) {
+	switch (type) {
+	case READABLE_PRED:
+		return "-readable";
+	case WRITABLE_PRED:
+		return "-writable";
+	case EXECUTABLE_PRED:
+		return "-executable";
+	case ACL_PRED:
+		return "-acl";
+	case CAPABLE_PRED:
+		return "-capable";
+	case EMPTY_PRED:
+		return "-empty";
+	case HIDDEN_PRED:
+		return "-hidden";
+	case NOGROUP_PRED:
+		return "-nogroup";
+	case NOUSER_PRED:
+		return "-nouser";
+	case SPARSE_PRED:
+		return "-sparse";
+	case XATTR_PRED:
+		return "-xattr";
+
+	case PRED_TYPES:
+		break;
+	}
+
+	bfs_bug("Unknown predicate %d", (int)type);
+	return "???";
+}
+
 /**
  * A contrained integer range.
  */
@@ -97,6 +163,11 @@ static void range_init_top(struct df_range *range) {
 	range->max = LLONG_MAX;
 }
 
+/** Check for an infinite range. */
+static bool range_is_top(const struct df_range *range) {
+	return range->min == 0 && range->max == LLONG_MAX;
+}
+
 /** Compute the minimum of two values. */
 static long long min_value(long long a, long long b) {
 	if (a < b) {
@@ -170,35 +241,29 @@ enum range_type {
 	RANGE_TYPES,
 };
 
-/**
- * Types of predicates we track.
- */
-enum pred_type {
-	/** -readable */
-	READABLE_PRED,
-	/** -writable */
-	WRITABLE_PRED,
-	/** -executable */
-	EXECUTABLE_PRED,
-	/** -acl */
-	ACL_PRED,
-	/** -capable */
-	CAPABLE_PRED,
-	/** -empty */
-	EMPTY_PRED,
-	/** -hidden */
-	HIDDEN_PRED,
-	/** -nogroup */
-	NOGROUP_PRED,
-	/** -nouser */
-	NOUSER_PRED,
-	/** -sparse */
-	SPARSE_PRED,
-	/** -xattr */
-	XATTR_PRED,
-	/** The number of pred_types. */
-	PRED_TYPES,
-};
+/** Get the name of a range type. */
+static const char *range_type_name(enum range_type type) {
+	switch (type) {
+	case DEPTH_RANGE:
+		return "-depth";
+	case GID_RANGE:
+		return "-gid";
+	case INUM_RANGE:
+		return "-inum";
+	case LINKS_RANGE:
+		return "-links";
+	case SIZE_RANGE:
+		return "-size";
+	case UID_RANGE:
+		return "-uid";
+
+	case RANGE_TYPES:
+		break;
+	}
+
+	bfs_bug("Unknown range %d", (int)type);
+	return "???";
+}
 
 /**
  * The data flow analysis domain.
@@ -210,9 +275,9 @@ struct df_domain {
 	/** The value ranges we track. */
 	struct df_range ranges[RANGE_TYPES];
 
-	/** Bitmask of possible file types. */
+	/** Bitmask of possible -types. */
 	unsigned int types;
-	/** Bitmask of possible link target types. */
+	/** Bitmask of possible -xtypes. */
 	unsigned int xtypes;
 };
 
@@ -265,6 +330,31 @@ static void df_init_top(struct df_domain *value) {
 	value->xtypes = ~0;
 }
 
+/** Check for the top element. */
+static bool df_is_top(const struct df_domain *value) {
+        for (int i = 0; i < PRED_TYPES; ++i) {
+                if (value->preds[i] != PRED_TOP) {
+                        return false;
+                }
+        }
+
+        for (int i = 0; i < RANGE_TYPES; ++i) {
+                if (!range_is_top(&value->ranges[i])) {
+                        return false;
+                }
+        }
+
+        if (value->types != ~0U) {
+                return false;
+        }
+
+        if (value->xtypes != ~0U) {
+                return false;
+        }
+
+        return true;
+}
+
 /** Compute the union of two fact sets. */
 static void df_join(struct df_domain *dest, const struct df_domain *src) {
 	for (int i = 0; i < PRED_TYPES; ++i) {
@@ -285,6 +375,15 @@ static void df_join(struct df_domain *dest, const struct df_domain *src) {
 struct bfs_opt {
 	/** The context we're optimizing. */
 	struct bfs_ctx *ctx;
+	/** Optimization level (ctx->optlevel). */
+	int level;
+	/** Recursion depth. */
+	int depth;
+
+	/** Whether to produce warnings. */
+	bool warn;
+	/** Whether the result of this expression is ignored. */
+	bool ignore_result;
 
 	/** Data flow state before this expression is evaluated. */
 	struct df_domain before;
@@ -296,18 +395,14 @@ struct bfs_opt {
 	struct df_domain *impure;
 };
 
-/** Constrain the value of a predicate. */
-static void opt_constrain_pred(struct bfs_opt *opt, enum pred_type type, bool value) {
-	constrain_pred(&opt->after_true.preds[type], value);
-	constrain_pred(&opt->after_false.preds[type], !value);
-}
-
 /** Log an optimization. */
-attr(printf(3, 4))
-static bool opt_debug(const struct bfs_opt *opt, int level, const char *format, ...) {
-	bfs_assert(opt->ctx->optlevel >= level);
+attr(printf(2, 3))
+static bool opt_debug(struct bfs_opt *opt, const char *format, ...) {
+	if (bfs_debug_prefix(opt->ctx, DEBUG_OPT)) {
+		for (int i = 0; i < opt->depth; ++i) {
+			cfprintf(opt->ctx->cerr, "│ ");
+		}
 
-	if (bfs_debug(opt->ctx, DEBUG_OPT, "${cyn}-O%d${rs}: ", level)) {
 		va_list args;
 		va_start(args, format);
 		cvfprintf(opt->ctx->cerr, format, args);
@@ -318,450 +413,577 @@ static bool opt_debug(const struct bfs_opt *opt, int level, const char *format,
 	}
 }
 
-/** Warn about an expression. */
-attr(printf(3, 4))
-static void opt_warning(const struct bfs_opt *opt, const struct bfs_expr *expr, const char *format, ...) {
-	if (bfs_expr_warning(opt->ctx, expr)) {
+/** Log a recursive call. */
+attr(printf(2, 3))
+static bool opt_enter(struct bfs_opt *opt, const char *format, ...) {
+	int depth = opt->depth;
+	if (depth > 0) {
+		--opt->depth;
+	}
+
+	bool debug = opt_debug(opt, "%s", depth > 0 ? "├─╮ " : "");
+	if (debug) {
 		va_list args;
 		va_start(args, format);
-		bfs_vwarning(opt->ctx, format, args);
+		cvfprintf(opt->ctx->cerr, format, args);
 		va_end(args);
 	}
-}
 
-/** Create a constant expression. */
-static struct bfs_expr *opt_const(const struct bfs_opt *opt, bool value) {
-	static bfs_eval_fn *fns[] = {eval_false, eval_true};
-	static char *fake_args[] = {"-false", "-true"};
-	return bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value]);
+	opt->depth = depth + 1;
+	return debug;
 }
 
-/**
- * Negate an expression.
- */
-static struct bfs_expr *negate_expr(const struct bfs_opt *opt, struct bfs_expr *rhs, char **argv) {
-	if (rhs->eval_fn == eval_not) {
-		return rhs->rhs;
-	}
+/** Log a recursive return. */
+attr(printf(2, 3))
+static bool opt_leave(struct bfs_opt *opt, const char *format, ...) {
+	bool debug = false;
+	int depth = opt->depth;
 
-	struct bfs_expr *expr = bfs_expr_new(opt->ctx, eval_not, 1, argv);
-	if (!expr) {
-		return NULL;
+	if (format) {
+		if (depth > 1) {
+			opt->depth -= 2;
+		}
+
+		debug = opt_debug(opt, "%s", depth > 1 ? "├─╯ " : "");
+		if (debug) {
+			va_list args;
+			va_start(args, format);
+			cvfprintf(opt->ctx->cerr, format, args);
+			va_end(args);
+		}
 	}
 
-	expr->lhs = NULL;
-	expr->rhs = rhs;
-	return expr;
+	opt->depth = depth - 1;
+	return debug;
 }
 
-static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
-static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
-static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_expr *expr);
-
-/**
- * Apply De Morgan's laws.
- */
-static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *expr, char **argv) {
-	bool debug = opt_debug(opt, 1, "De Morgan's laws: %pe ", expr);
-
-	struct bfs_expr *parent = negate_expr(opt, expr, argv);
-	if (!parent) {
-		return NULL;
+/** Log a shallow visit. */
+attr(printf(2, 3))
+static bool opt_visit(struct bfs_opt *opt, const char *format, ...) {
+	int depth = opt->depth;
+	if (depth > 0) {
+		--opt->depth;
 	}
 
-	bool has_parent = true;
-	if (parent->eval_fn != eval_not) {
-		expr = parent;
-		has_parent = false;
+	bool debug = opt_debug(opt, "%s", depth > 0 ? "├─◯ " : "");
+	if (debug) {
+		va_list args;
+		va_start(args, format);
+		cvfprintf(opt->ctx->cerr, format, args);
+		va_end(args);
 	}
 
-	bfs_assert(expr->eval_fn == eval_and || expr->eval_fn == eval_or);
-	if (expr->eval_fn == eval_and) {
-		expr->eval_fn = eval_or;
-		expr->argv = &fake_or_arg;
-	} else {
-		expr->eval_fn = eval_and;
-		expr->argv = &fake_and_arg;
-	}
+	opt->depth = depth;
+	return debug;
+}
 
-	expr->lhs = negate_expr(opt, expr->lhs, argv);
-	expr->rhs = negate_expr(opt, expr->rhs, argv);
-	if (!expr->lhs || !expr->rhs) {
-		return NULL;
+/** Log the deletion of an expression. */
+attr(printf(2, 3))
+static bool opt_delete(struct bfs_opt *opt, const char *format, ...) {
+	int depth = opt->depth;
+
+	if (depth > 0) {
+		--opt->depth;
 	}
 
+	bool debug = opt_debug(opt, "%s", depth > 0 ? "├─✘ " : "");
 	if (debug) {
-		cfprintf(opt->ctx->cerr, "<==> %pe\n", parent);
+		va_list args;
+		va_start(args, format);
+		cvfprintf(opt->ctx->cerr, format, args);
+		va_end(args);
 	}
 
-	if (expr->lhs->eval_fn == eval_not) {
-		expr->lhs = optimize_not_expr(opt, expr->lhs);
-	}
-	if (expr->rhs->eval_fn == eval_not) {
-		expr->rhs = optimize_not_expr(opt, expr->rhs);
-	}
-	if (!expr->lhs || !expr->rhs) {
-		return NULL;
-	}
+	opt->depth = depth;
+	return debug;
+}
 
-	if (expr->eval_fn == eval_and) {
-		expr = optimize_and_expr(opt, expr);
-	} else {
-		expr = optimize_or_expr(opt, expr);
+typedef bool dump_fn(struct bfs_opt *opt, const char *format, ...);
+
+/** Print a df_pred. */
+static void pred_dump(dump_fn *dump, struct bfs_opt *opt, const struct df_domain *value, enum pred_type type) {
+	dump(opt, "${blu}%s${rs}: ", pred_type_name(type));
+
+	FILE *file = opt->ctx->cerr->file;
+	switch (value->preds[type]) {
+	case PRED_BOTTOM:
+		fprintf(file, "⊥\n");
+		break;
+	case PRED_TOP:
+		fprintf(file, "⊤\n");
+		break;
+	case PRED_TRUE:
+		fprintf(file, "true\n");
+		break;
+	case PRED_FALSE:
+		fprintf(file, "false\n");
+		break;
 	}
-	if (has_parent) {
-		parent->rhs = expr;
+}
+
+/** Print a df_range. */
+static void range_dump(dump_fn *dump, struct bfs_opt *opt, const struct df_domain *value, enum range_type type) {
+	dump(opt, "${blu}%s${rs}: ", range_type_name(type));
+
+	FILE *file = opt->ctx->cerr->file;
+	const struct df_range *range = &value->ranges[type];
+	if (range_is_bottom(range)) {
+		fprintf(file, "⊥\n");
+	} else if (range_is_top(range)) {
+		fprintf(file, "⊤\n");
+	} else if (range->min == range->max) {
+		fprintf(file, "%lld\n", range->min);
 	} else {
-		parent = expr;
-	}
-	if (!expr) {
-		return NULL;
+		if (range->min == LLONG_MIN) {
+			fprintf(file, "(-∞, ");
+		} else {
+			fprintf(file, "[%lld, ", range->min);
+		}
+		if (range->max == LLONG_MAX) {
+			fprintf(file, "∞)\n");
+		} else {
+			fprintf(file, "%lld]\n", range->max);
+		}
 	}
+}
 
-	if (has_parent) {
-		parent = optimize_not_expr(opt, parent);
+/** Print a set of types. */
+static void types_dump(dump_fn *dump, struct bfs_opt *opt, const char *name, unsigned int types) {
+	dump(opt, "${blu}%s${rs}: ", name);
+
+	FILE *file = opt->ctx->cerr->file;
+	if (types == 0) {
+		fprintf(file, " ⊥\n");
+	} else if (types == ~0U) {
+		fprintf(file, " ⊤\n");
+	} else if (count_ones(types) < count_ones(~types)) {
+		fprintf(file, " 0x%X\n", types);
+	} else {
+		fprintf(file, "~0x%X\n", ~types);
 	}
-	return parent;
 }
 
-/** Optimize an expression recursively. */
-static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr);
+/** Calculate the number of lines of df_dump() output. */
+static int df_dump_lines(const struct df_domain *value) {
+	int lines = 0;
 
-/**
- * Optimize a negation.
- */
-static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	bfs_assert(expr->eval_fn == eval_not);
-
-	struct bfs_expr *rhs = expr->rhs;
-
-	int optlevel = opt->ctx->optlevel;
-	if (optlevel >= 1) {
-		if (rhs->eval_fn == eval_true || rhs->eval_fn == eval_false) {
-			struct bfs_expr *ret = opt_const(opt, rhs->eval_fn == eval_false);
-			opt_debug(opt, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
-			return ret;
-		} else if (rhs->eval_fn == eval_not) {
-			opt_debug(opt, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
-			return rhs->rhs;
-		} else if (bfs_expr_never_returns(rhs)) {
-			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, rhs);
-			return expr->rhs;
-		} else if ((rhs->eval_fn == eval_and || rhs->eval_fn == eval_or)
-			   && (rhs->lhs->eval_fn == eval_not || rhs->rhs->eval_fn == eval_not)) {
-			return de_morgan(opt, expr, expr->argv);
-		}
+	for (int i = 0; i < PRED_TYPES; ++i) {
+		lines += value->preds[i] != PRED_TOP;
 	}
 
-	expr->pure = rhs->pure;
-	expr->always_true = rhs->always_false;
-	expr->always_false = rhs->always_true;
-	expr->cost = rhs->cost;
-	expr->probability = 1.0 - rhs->probability;
+	for (int i = 0; i < RANGE_TYPES; ++i) {
+		lines += !range_is_top(&value->ranges[i]);
+	}
 
-	return expr;
+	lines += value->types != ~0U;
+	lines += value->xtypes != ~0U;
+
+	return lines;
 }
 
-/** Optimize a negation recursively. */
-static struct bfs_expr *optimize_not_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct bfs_opt rhs_state = *opt;
-	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
-	if (!expr->rhs) {
-		return NULL;
+/** Get the right debugging function for a df_dump() line. */
+static dump_fn *df_dump_line(int lines, int *line) {
+	++*line;
+
+	if (lines == 1) {
+		return opt_visit;
+	} else if (*line == 1) {
+		return opt_enter;
+	} else if (*line == lines) {
+		return opt_leave;
+	} else {
+		return opt_debug;
 	}
+}
 
-	opt->after_true = rhs_state.after_false;
-	opt->after_false = rhs_state.after_true;
-
-	return optimize_not_expr(opt, expr);
-}
-
-/** Optimize a conjunction. */
-static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	bfs_assert(expr->eval_fn == eval_and);
-
-	struct bfs_expr *lhs = expr->lhs;
-	struct bfs_expr *rhs = expr->rhs;
-
-	const struct bfs_ctx *ctx = opt->ctx;
-	int optlevel = ctx->optlevel;
-	if (optlevel >= 1) {
-		if (lhs->eval_fn == eval_true) {
-			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
-			return expr->rhs;
-		} else if (rhs->eval_fn == eval_true) {
-			opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
-			return expr->lhs;
-		} else if (lhs->always_false) {
-			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
-			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return expr->lhs;
-		} else if (lhs->always_true && rhs->eval_fn == eval_false) {
-			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
-			struct bfs_expr *ret = expr->lhs;
-			ret = negate_expr(opt, ret, &fake_not_arg);
-			if (debug && ret) {
-				cfprintf(ctx->cerr, "%pe\n", ret);
-			}
-			return ret;
-		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_false) {
-			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return expr->rhs;
-		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
-			return de_morgan(opt, expr, expr->lhs->argv);
-		}
+/** Print a data flow value. */
+static void df_dump(struct bfs_opt *opt, const char *str, const struct df_domain *value) {
+	if (df_is_bottom(value)) {
+		opt_debug(opt, "%s: ⊥\n", str);
+		return;
+	} else if (df_is_top(value)) {
+		opt_debug(opt, "%s: ⊤\n", str);
+		return;
 	}
 
-	expr->pure = lhs->pure && rhs->pure;
-	expr->always_true = lhs->always_true && rhs->always_true;
-	expr->always_false = lhs->always_false || rhs->always_false;
-	expr->cost = lhs->cost + lhs->probability * rhs->cost;
-	expr->probability = lhs->probability * rhs->probability;
+	if (!opt_debug(opt, "%s:\n", str)) {
+		return;
+	}
 
-	return expr;
-}
+	int lines = df_dump_lines(value);
+	int line = 0;
 
-/** Optimize a conjunction recursively. */
-static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct bfs_opt lhs_state = *opt;
-	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
-	if (!expr->lhs) {
-		return NULL;
+	for (int i = 0; i < PRED_TYPES; ++i) {
+		if (value->preds[i] != PRED_TOP) {
+			pred_dump(df_dump_line(lines, &line), opt, value, i);
+		}
 	}
 
-	struct bfs_opt rhs_state = *opt;
-	rhs_state.before = lhs_state.after_true;
-	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
-	if (!expr->rhs) {
-		return NULL;
+	for (int i = 0; i < RANGE_TYPES; ++i) {
+		if (!range_is_top(&value->ranges[i])) {
+			range_dump(df_dump_line(lines, &line), opt, value, i);
+		}
 	}
 
-	opt->after_true = rhs_state.after_true;
-	opt->after_false = lhs_state.after_false;
-	df_join(&opt->after_false, &rhs_state.after_false);
-
-	return optimize_and_expr(opt, expr);
-}
-
-/** Optimize a disjunction. */
-static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	bfs_assert(expr->eval_fn == eval_or);
-
-	struct bfs_expr *lhs = expr->lhs;
-	struct bfs_expr *rhs = expr->rhs;
-
-	const struct bfs_ctx *ctx = opt->ctx;
-	int optlevel = ctx->optlevel;
-	if (optlevel >= 1) {
-		if (lhs->always_true) {
-			opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
-			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return expr->lhs;
-		} else if (lhs->eval_fn == eval_false) {
-			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
-			return expr->rhs;
-		} else if (rhs->eval_fn == eval_false) {
-			opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
-			return expr->lhs;
-		} else if (lhs->always_false && rhs->eval_fn == eval_true) {
-			bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
-			struct bfs_expr *ret = expr->lhs;
-			ret = negate_expr(opt, ret, &fake_not_arg);
-			if (debug && ret) {
-				cfprintf(ctx->cerr, "%pe\n", ret);
-			}
-			return ret;
-		} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_true) {
-			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return expr->rhs;
-		} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
-			return de_morgan(opt, expr, expr->lhs->argv);
-		}
+	if (value->types != ~0U) {
+		types_dump(df_dump_line(lines, &line), opt, "-type", value->types);
 	}
 
-	expr->pure = lhs->pure && rhs->pure;
-	expr->always_true = lhs->always_true || rhs->always_true;
-	expr->always_false = lhs->always_false && rhs->always_false;
-	expr->cost = lhs->cost + (1 - lhs->probability) * rhs->cost;
-	expr->probability = lhs->probability + rhs->probability - lhs->probability * rhs->probability;
+	if (value->xtypes != ~0U) {
+		types_dump(df_dump_line(lines, &line), opt, "-xtype", value->xtypes);
+	}
+}
 
-	return expr;
+/** Check if an expression is constant. */
+static bool is_const(const struct bfs_expr *expr) {
+	return expr->eval_fn == eval_true || expr->eval_fn == eval_false;
 }
 
-/** Optimize a disjunction recursively. */
-static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct bfs_opt lhs_state = *opt;
-	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
-	if (!expr->lhs) {
-		return NULL;
+/** Warn about an expression. */
+attr(printf(3, 4))
+static void opt_warning(const struct bfs_opt *opt, const struct bfs_expr *expr, const char *format, ...) {
+	if (!opt->warn) {
+		return;
 	}
 
-	struct bfs_opt rhs_state = *opt;
-	rhs_state.before = lhs_state.after_false;
-	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
-	if (!expr->rhs) {
-		return NULL;
+	if (bfs_expr_is_parent(expr) || is_const(expr)) {
+		return;
 	}
 
-	opt->after_false = rhs_state.after_false;
-	opt->after_true = lhs_state.after_true;
-	df_join(&opt->after_true, &rhs_state.after_true);
-
-	return optimize_or_expr(opt, expr);
+	if (bfs_expr_warning(opt->ctx, expr)) {
+		va_list args;
+		va_start(args, format);
+		bfs_vwarning(opt->ctx, format, args);
+		va_end(args);
+	}
 }
 
-/** Optimize an expression in an ignored-result context. */
-static struct bfs_expr *ignore_result(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	int optlevel = opt->ctx->optlevel;
+/** Remove and return an expression's children. */
+static void foster_children(struct bfs_expr *expr, struct bfs_exprs *children) {
+	bfs_assert(bfs_expr_is_parent(expr));
 
-	if (optlevel >= 1) {
-		while (true) {
-			if (expr->eval_fn == eval_not) {
-				opt_debug(opt, 1, "ignored result: %pe --> %pe\n", expr, expr->rhs);
-				opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
-				expr = expr->rhs;
-			} else if (optlevel >= 2
-			           && (expr->eval_fn == eval_and || expr->eval_fn == eval_or || expr->eval_fn == eval_comma)
-			           && expr->rhs->pure) {
-				opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, expr->lhs);
-				opt_warning(opt, expr->rhs, "The result of this expression is ignored.\n\n");
-				expr = expr->lhs;
-			} else {
-				break;
-			}
-		}
+	SLIST_INIT(children);
+	SLIST_EXTEND(children, &expr->children);
 
-		if (optlevel >= 2 && expr->pure && expr->eval_fn != eval_false) {
-			struct bfs_expr *ret = opt_const(opt, false);
-			opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, ret);
-			opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
-			return ret;
-		}
-	}
+	expr->persistent_fds = 0;
+	expr->ephemeral_fds = 0;
+	expr->pure = true;
+}
 
-	return expr;
+/** Return an expression's only child. */
+static struct bfs_expr *only_child(struct bfs_expr *expr) {
+	bfs_assert(bfs_expr_is_parent(expr));
+	struct bfs_expr *child = bfs_expr_children(expr);
+	bfs_assert(child && !child->next);
+	return child;
 }
 
-/** Optimize a comma expression. */
-static struct bfs_expr *optimize_comma_expr(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	bfs_assert(expr->eval_fn == eval_comma);
+/** Foster an expression's only child. */
+static struct bfs_expr *foster_only_child(struct bfs_expr *expr) {
+	struct bfs_expr *child = only_child(expr);
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+	return child;
+}
 
-	struct bfs_expr *lhs = expr->lhs;
-	struct bfs_expr *rhs = expr->rhs;
-
-	int optlevel = opt->ctx->optlevel;
-	if (optlevel >= 1) {
-		lhs = expr->lhs = ignore_result(opt, lhs);
-
-		if (bfs_expr_never_returns(lhs)) {
-			opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, lhs);
-			opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
-			return expr->lhs;
-		} else if ((lhs->always_true && rhs->eval_fn == eval_true)
-			   || (lhs->always_false && rhs->eval_fn == eval_false)) {
-			opt_debug(opt, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
-			return expr->lhs;
-		} else if (optlevel >= 2 && lhs->pure) {
-			opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
-			opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
-			return expr->rhs;
+/** An expression visitor. */
+struct visitor;
+
+/** An expression-visiting function. */
+typedef struct bfs_expr *visit_fn(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor);
+
+/** An entry in a visitor lookup table. */
+struct visitor_table {
+	/** The evaluation function to match on. */
+	bfs_eval_fn *eval_fn;
+	/** The visitor function. */
+	visit_fn *visit;
+};
+
+/** Look up a visitor in a table. */
+static visit_fn *look_up_visitor(const struct bfs_expr *expr, const struct visitor_table table[]) {
+	for (size_t i = 0; table[i].eval_fn; ++i) {
+		if (expr->eval_fn == table[i].eval_fn) {
+			return table[i].visit;
 		}
 	}
 
-	expr->pure = lhs->pure && rhs->pure;
-	expr->always_true = bfs_expr_never_returns(lhs) || rhs->always_true;
-	expr->always_false = bfs_expr_never_returns(lhs) || rhs->always_false;
-	expr->cost = lhs->cost + rhs->cost;
-	expr->probability = rhs->probability;
-
-	return expr;
+	return NULL;
 }
 
-/** Optimize a comma expression recursively. */
-static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct bfs_opt lhs_state = *opt;
-	expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
-	if (!expr->lhs) {
-		return NULL;
-	}
+struct visitor {
+	/** The name of this visitor. */
+	const char *name;
+
+	/** A function to call before visiting children. */
+	visit_fn *enter;
+	/** The default visitor. */
+	visit_fn *visit;
+	/** A function to call after visiting children. */
+	visit_fn *leave;
+
+	/** A visitor lookup table. */
+	struct visitor_table table[];
+};
 
-	struct bfs_opt rhs_state = *opt;
-	rhs_state.before = lhs_state.after_true;
-	df_join(&rhs_state.before, &lhs_state.after_false);
+/** Recursive visitor implementation. */
+static struct bfs_expr *visit_deep(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor);
 
-	expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
-	if (!expr->rhs) {
+/** Visit a negation. */
+static struct bfs_expr *visit_not(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_expr *rhs = foster_only_child(expr);
+
+	struct bfs_opt nested = *opt;
+	rhs = visit_deep(&nested, rhs, visitor);
+	if (!rhs) {
 		return NULL;
 	}
 
-	return optimize_comma_expr(opt, expr);
+	opt->after_true = nested.after_false;
+	opt->after_false = nested.after_true;
+
+	bfs_expr_append(expr, rhs);
+	return expr;
 }
 
-/** Optimize an icmp-style ([+-]N) expression. */
-static void optimize_icmp(struct bfs_opt *opt, const struct bfs_expr *expr, enum range_type type) {
-	struct df_range *true_range = &opt->after_true.ranges[type];
-	struct df_range *false_range = &opt->after_false.ranges[type];
-	long long value = expr->num;
+/** Visit a conjunction. */
+static struct bfs_expr *visit_and(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
 
-	switch (expr->int_cmp) {
-	case BFS_INT_EQUAL:
-		constrain_min(true_range, value);
-		constrain_max(true_range, value);
-		range_remove(false_range, value);
-		break;
+	// Base case (-and) == (-true)
+	df_init_bottom(&opt->after_false);
+	struct bfs_opt nested = *opt;
 
-	case BFS_INT_LESS:
-		constrain_min(false_range, value);
-		constrain_max(true_range, value);
-		range_remove(true_range, value);
-		break;
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
 
-	case BFS_INT_GREATER:
-		constrain_max(false_range, value);
-		constrain_min(true_range, value);
-		range_remove(true_range, value);
-		break;
-	}
-}
+		if (SLIST_EMPTY(&children)) {
+			nested.ignore_result = opt->ignore_result;
+		} else {
+			nested.ignore_result = false;
+		}
 
-/** Optimize -{execut,read,writ}able. */
-static struct bfs_expr *optimize_access(struct bfs_opt *opt, struct bfs_expr *expr) {
-	expr->probability = 1.0;
+		child = visit_deep(&nested, child, visitor);
+		if (!child) {
+			return NULL;
+		}
 
-	if (expr->num & R_OK) {
-		opt_constrain_pred(opt, READABLE_PRED, true);
-		expr->probability *= 0.99;
-	}
+		df_join(&opt->after_false, &nested.after_false);
+		nested.before = nested.after_true;
 
-	if (expr->num & W_OK) {
-		opt_constrain_pred(opt, WRITABLE_PRED, true);
-		expr->probability *= 0.8;
+		bfs_expr_append(expr, child);
 	}
 
-	if (expr->num & X_OK) {
-		opt_constrain_pred(opt, EXECUTABLE_PRED, true);
-		expr->probability *= 0.2;
-	}
+	opt->after_true = nested.after_true;
 
 	return expr;
 }
 
-/** Optimize -empty. */
-static struct bfs_expr *optimize_empty(struct bfs_opt *opt, struct bfs_expr *expr) {
-	if (opt->ctx->optlevel >= 4) {
-		// Since -empty attempts to open and read directories, it may
-		// have side effects such as reporting permission errors, and
-		// thus shouldn't be re-ordered without aggressive optimizations
-		expr->pure = true;
-	}
+/** Visit a disjunction. */
+static struct bfs_expr *visit_or(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
 
-	return expr;
-}
+	// Base case (-or) == (-false)
+	df_init_bottom(&opt->after_true);
+	struct bfs_opt nested = *opt;
 
-/** Optimize -{exec,ok}{,dir}. */
-static struct bfs_expr *optimize_exec(struct bfs_opt *opt, struct bfs_expr *expr) {
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
+
+		if (SLIST_EMPTY(&children)) {
+			nested.ignore_result = opt->ignore_result;
+		} else {
+			nested.ignore_result = false;
+		}
+
+		child = visit_deep(&nested, child, visitor);
+		if (!child) {
+			return NULL;
+		}
+
+		df_join(&opt->after_true, &nested.after_true);
+		nested.before = nested.after_false;
+
+		bfs_expr_append(expr, child);
+	}
+
+	opt->after_false = nested.after_false;
+
+	return expr;
+}
+
+/** Visit a comma expression. */
+static struct bfs_expr *visit_comma(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	struct bfs_opt nested = *opt;
+
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
+
+		if (SLIST_EMPTY(&children)) {
+			nested.ignore_result = opt->ignore_result;
+		} else {
+			nested.ignore_result = true;
+		}
+
+		child = visit_deep(&nested, child, visitor);
+		if (!child) {
+			return NULL;
+		}
+
+		nested.before = nested.after_true;
+		df_join(&nested.before, &nested.after_false);
+
+		bfs_expr_append(expr, child);
+	}
+
+	opt->after_true = nested.after_true;
+	opt->after_false = nested.after_false;
+
+	return expr;
+}
+
+/** Default enter() function. */
+static struct bfs_expr *visit_enter(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	opt_enter(opt, "%pe\n", expr);
+	opt->after_true = opt->before;
+	opt->after_false = opt->before;
+	return expr;
+}
+
+/** Default leave() function. */
+static struct bfs_expr *visit_leave(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	opt_leave(opt, "%pe\n", expr);
+	return expr;
+}
+
+static struct bfs_expr *visit_deep(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	bool entered = false;
+
+	visit_fn *enter = visitor->enter ? visitor->enter : visit_enter;
+	visit_fn *leave = visitor->leave ? visitor->leave : visit_leave;
+
+	static const struct visitor_table table[] = {
+		{eval_not, visit_not},
+		{eval_and, visit_and},
+		{eval_or, visit_or},
+		{eval_comma, visit_comma},
+		{NULL, NULL},
+	};
+	visit_fn *recursive = look_up_visitor(expr, table);
+	if (recursive) {
+		if (!entered) {
+			expr = enter(opt, expr, visitor);
+			if (!expr) {
+				return NULL;
+			}
+			entered = true;
+		}
+
+		expr = recursive(opt, expr, visitor);
+		if (!expr) {
+			return NULL;
+		}
+	}
+
+	visit_fn *general = visitor->visit;
+	if (general) {
+		if (!entered) {
+			expr = enter(opt, expr, visitor);
+			if (!expr) {
+				return NULL;
+			}
+			entered = true;
+		}
+
+		expr = general(opt, expr, visitor);
+		if (!expr) {
+			return NULL;
+		}
+	}
+
+	visit_fn *specific = look_up_visitor(expr, visitor->table);
+	if (specific) {
+		if (!entered) {
+			expr = enter(opt, expr, visitor);
+			if (!expr) {
+				return NULL;
+			}
+			entered = true;
+		}
+
+		expr = specific(opt, expr, visitor);
+		if (!expr) {
+			return NULL;
+		}
+	}
+
+	if (entered) {
+		expr = leave(opt, expr, visitor);
+	} else {
+		opt_visit(opt, "%pe\n", expr);
+	}
+
+	return expr;
+}
+
+/** Visit an expression recursively. */
+static struct bfs_expr *visit(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	opt_enter(opt, "%s()\n", visitor->name);
+	expr = visit_deep(opt, expr, visitor);
+	opt_leave(opt, "\n");
+	return expr;
+}
+
+/** Visit an expression non-recursively. */
+static struct bfs_expr *visit_shallow(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	visit_fn *general = visitor->visit;
+	if (expr && general) {
+		expr = general(opt, expr, visitor);
+	}
+
+	visit_fn *specific = look_up_visitor(expr, visitor->table);
+	if (expr && specific) {
+		expr = specific(opt, expr, visitor);
+	}
+
+	return expr;
+}
+
+/** Annotate -{execut,read,writ}able. */
+static struct bfs_expr *annotate_access(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	expr->probability = 1.0;
+	if (expr->num & R_OK) {
+		expr->probability *= 0.99;
+	}
+	if (expr->num & W_OK) {
+		expr->probability *= 0.8;
+	}
+	if (expr->num & X_OK) {
+		expr->probability *= 0.2;
+	}
+
+	return expr;
+}
+
+/** Annotate -empty. */
+static struct bfs_expr *annotate_empty(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (opt->level >= 4) {
+		// Since -empty attempts to open and read directories, it may
+		// have side effects such as reporting permission errors, and
+		// thus shouldn't be re-ordered without aggressive optimizations
+		expr->pure = true;
+	}
+
+	return expr;
+}
+
+/** Annotate -exec. */
+static struct bfs_expr *annotate_exec(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	if (expr->exec->flags & BFS_EXEC_MULTI) {
 		expr->always_true = true;
 	} else {
@@ -771,33 +993,650 @@ static struct bfs_expr *optimize_exec(struct bfs_opt *opt, struct bfs_expr *expr
 	return expr;
 }
 
-/** Optimize -name/-lname/-path. */
-static struct bfs_expr *optimize_fnmatch(struct bfs_opt *opt, struct bfs_expr *expr) {
-	if (strchr(expr->argv[1], '*')) {
+/** Annotate -name/-lname/-path. */
+static struct bfs_expr *annotate_fnmatch(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (expr->literal) {
+		expr->probability = 0.1;
+	} else {
 		expr->probability = 0.5;
+	}
+
+	return expr;
+}
+
+/** Estimate probability for -x?type. */
+static void estimate_type_probability(struct bfs_expr *expr) {
+	unsigned int types = expr->num;
+
+	expr->probability = 0.0;
+	if (types & (1 << BFS_BLK)) {
+		expr->probability += 0.00000721183;
+	}
+	if (types & (1 << BFS_CHR)) {
+		expr->probability += 0.0000499855;
+	}
+	if (types & (1 << BFS_DIR)) {
+		expr->probability += 0.114475;
+	}
+	if (types & (1 << BFS_DOOR)) {
+		expr->probability += 0.000001;
+	}
+	if (types & (1 << BFS_FIFO)) {
+		expr->probability += 0.00000248684;
+	}
+	if (types & (1 << BFS_REG)) {
+		expr->probability += 0.859772;
+	}
+	if (types & (1 << BFS_LNK)) {
+		expr->probability += 0.0256816;
+	}
+	if (types & (1 << BFS_SOCK)) {
+		expr->probability += 0.0000116881;
+	}
+	if (types & (1 << BFS_WHT)) {
+		expr->probability += 0.000001;
+	}
+}
+
+/** Annotate -type. */
+static struct bfs_expr *annotate_type(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	estimate_type_probability(expr);
+	return expr;
+}
+
+/** Annotate -xtype. */
+static struct bfs_expr *annotate_xtype(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (opt->level >= 4) {
+		// Since -xtype dereferences symbolic links, it may have side
+		// effects such as reporting permission errors, and thus
+		// shouldn't be re-ordered without aggressive optimizations
+		expr->pure = true;
+	}
+
+	estimate_type_probability(expr);
+	return expr;
+}
+
+/** Annotate a negation. */
+static struct bfs_expr *annotate_not(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_expr *rhs = only_child(expr);
+	expr->pure = rhs->pure;
+	expr->always_true = rhs->always_false;
+	expr->always_false = rhs->always_true;
+	expr->cost = rhs->cost;
+	expr->probability = 1.0 - rhs->probability;
+	return expr;
+}
+
+/** Annotate a conjunction. */
+static struct bfs_expr *annotate_and(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	expr->pure = true;
+	expr->always_true = true;
+	expr->always_false = false;
+	expr->cost = 0.0;
+	expr->probability = 1.0;
+
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		expr->pure &= child->pure;
+		expr->always_true &= child->always_true;
+		expr->always_false |= child->always_false;
+		expr->cost += expr->probability * child->cost;
+		expr->probability *= child->probability;
+	}
+
+	return expr;
+}
+
+/** Annotate a disjunction. */
+static struct bfs_expr *annotate_or(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	expr->pure = true;
+	expr->always_true = false;
+	expr->always_false = true;
+	expr->cost = 0.0;
+
+	float false_prob = 1.0;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		expr->pure &= child->pure;
+		expr->always_true |= child->always_true;
+		expr->always_false &= child->always_false;
+		expr->cost += false_prob * child->cost;
+		false_prob *= (1.0 - child->probability);
+	}
+	expr->probability = 1.0 - false_prob;
+
+	return expr;
+}
+
+/** Annotate a comma expression. */
+static struct bfs_expr *annotate_comma(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	expr->pure = true;
+	expr->cost = 0.0;
+
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		expr->pure &= child->pure;
+		expr->always_true = child->always_true;
+		expr->always_false = child->always_false;
+		expr->cost += child->cost;
+		expr->probability = child->probability;
+	}
+
+	return expr;
+}
+
+/** Annotate an arbitrary expression. */
+static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	/** Table of pure expressions. */
+	static bfs_eval_fn *const pure[] = {
+		eval_access,
+		eval_acl,
+		eval_capable,
+		eval_depth,
+		eval_false,
+		eval_flags,
+		eval_fstype,
+		eval_gid,
+		eval_hidden,
+		eval_inum,
+		eval_links,
+		eval_lname,
+		eval_name,
+		eval_newer,
+		eval_nogroup,
+		eval_nouser,
+		eval_path,
+		eval_perm,
+		eval_regex,
+		eval_samefile,
+		eval_size,
+		eval_sparse,
+		eval_time,
+		eval_true,
+		eval_type,
+		eval_uid,
+		eval_used,
+		eval_xattr,
+		eval_xattrname,
+	};
+
+	expr->pure = false;
+	for (size_t i = 0; i < countof(pure); ++i) {
+		if (expr->eval_fn == pure[i]) {
+			expr->pure = true;
+			break;
+		}
+	}
+
+	/** Table of always-true expressions. */
+	static bfs_eval_fn *const always_true[] = {
+		eval_fls,
+		eval_fprint,
+		eval_fprint0,
+		eval_fprintf,
+		eval_fprintx,
+		eval_prune,
+		eval_true,
+		// Non-returning
+		eval_exit,
+		eval_quit,
+	};
+
+	expr->always_true = false;
+	for (size_t i = 0; i < countof(always_true); ++i) {
+		if (expr->eval_fn == always_true[i]) {
+			expr->always_true = true;
+			break;
+		}
+	}
+
+	/** Table of always-false expressions. */
+	static bfs_eval_fn *const always_false[] = {
+		eval_false,
+		// Non-returning
+		eval_exit,
+		eval_quit,
+	};
+
+	expr->always_false = false;
+	for (size_t i = 0; i < countof(always_false); ++i) {
+		if (expr->eval_fn == always_false[i]) {
+			expr->always_false = true;
+			break;
+		}
+	}
+
+#define FAST_COST       40.0
+#define FNMATCH_COST   400.0
+#define STAT_COST     1000.0
+#define PRINT_COST   20000.0
+
+	/** Table of expression costs. */
+	static const struct {
+		bfs_eval_fn *eval_fn;
+		float cost;
+	} costs[] = {
+		{eval_access,    STAT_COST},
+		{eval_acl,       STAT_COST},
+		{eval_capable,   STAT_COST},
+		{eval_empty, 2 * STAT_COST}, // readdir() is worse than stat()
+		{eval_fls,      PRINT_COST},
+		{eval_fprint,   PRINT_COST},
+		{eval_fprint0,  PRINT_COST},
+		{eval_fprintf,  PRINT_COST},
+		{eval_fprintx,  PRINT_COST},
+		{eval_fstype,    STAT_COST},
+		{eval_gid,       STAT_COST},
+		{eval_inum,      STAT_COST},
+		{eval_links,     STAT_COST},
+		{eval_lname,  FNMATCH_COST},
+		{eval_name,   FNMATCH_COST},
+		{eval_newer,     STAT_COST},
+		{eval_nogroup,   STAT_COST},
+		{eval_nouser,    STAT_COST},
+		{eval_path,   FNMATCH_COST},
+		{eval_perm,      STAT_COST},
+		{eval_samefile,  STAT_COST},
+		{eval_size,      STAT_COST},
+		{eval_sparse,    STAT_COST},
+		{eval_time,      STAT_COST},
+		{eval_uid,       STAT_COST},
+		{eval_used,      STAT_COST},
+		{eval_xattr,     STAT_COST},
+		{eval_xattrname, STAT_COST},
+	};
+
+	expr->cost = FAST_COST;
+	for (size_t i = 0; i < countof(costs); ++i) {
+		if (expr->eval_fn == costs[i].eval_fn) {
+			expr->cost = costs[i].cost;
+			break;
+		}
+	}
+
+	/** Table of expression probabilities. */
+	static const struct {
+		/** The evaluation function with this cost. */
+		bfs_eval_fn *eval_fn;
+		/** The matching probability. */
+		float probability;
+	} probs[] = {
+		{eval_acl,       0.00002},
+		{eval_capable,   0.000002},
+		{eval_empty,     0.01},
+		{eval_false,     0.0},
+		{eval_hidden,    0.01},
+		{eval_nogroup,   0.01},
+		{eval_nouser,    0.01},
+		{eval_samefile,  0.01},
+		{eval_true,      1.0},
+		{eval_xattr,     0.01},
+		{eval_xattrname, 0.01},
+	};
+
+	expr->probability = 0.5;
+	for (size_t i = 0; i < countof(probs); ++i) {
+		if (expr->eval_fn == probs[i].eval_fn) {
+			expr->probability = probs[i].probability;
+			break;
+		}
+	}
+
+	return expr;
+}
+
+/**
+ * Annotating visitor.
+ */
+static const struct visitor annotate = {
+	.name = "annotate",
+	.visit = annotate_visit,
+	.table = {
+		{eval_access, annotate_access},
+		{eval_empty, annotate_empty},
+		{eval_exec, annotate_exec},
+		{eval_lname, annotate_fnmatch},
+		{eval_name, annotate_fnmatch},
+		{eval_path, annotate_fnmatch},
+		{eval_type, annotate_type},
+		{eval_xtype, annotate_xtype},
+
+		{eval_not, annotate_not},
+		{eval_and, annotate_and},
+		{eval_or, annotate_or},
+		{eval_comma, annotate_comma},
+
+		{NULL, NULL},
+	},
+};
+
+/** Create a constant expression. */
+static struct bfs_expr *opt_const(struct bfs_opt *opt, bool value) {
+	static bfs_eval_fn *const fns[] = {eval_false, eval_true};
+	static char *fake_args[] = {"-false", "-true"};
+
+	struct bfs_expr *expr = bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value]);
+	return visit_shallow(opt, expr, &annotate);
+}
+
+/** Negate an expression, keeping it canonical. */
+static struct bfs_expr *negate_expr(struct bfs_opt *opt, struct bfs_expr *expr, char **argv) {
+	if (expr->eval_fn == eval_not) {
+		return only_child(expr);
+	} else if (expr->eval_fn == eval_true) {
+		return opt_const(opt, false);
+	} else if (expr->eval_fn == eval_false) {
+		return opt_const(opt, true);
+	}
+
+	struct bfs_expr *ret = bfs_expr_new(opt->ctx, eval_not, 1, argv);
+	if (!ret) {
+		return NULL;
+	}
+
+	bfs_expr_append(ret, expr);
+	return visit_shallow(opt, ret, &annotate);
+}
+
+/** Sink negations into a conjunction/disjunction using De Morgan's laws. */
+static struct bfs_expr *sink_not_andor(struct bfs_opt *opt, struct bfs_expr *expr) {
+	opt_debug(opt, "De Morgan's laws\n");
+
+	char **argv = expr->argv;
+	expr = only_child(expr);
+	opt_enter(opt, "%pe\n", expr);
+
+	if (expr->eval_fn == eval_and) {
+		expr->eval_fn = eval_or;
+		expr->argv = &fake_or_arg;
 	} else {
-		expr->probability = 0.1;
+		bfs_assert(expr->eval_fn == eval_or);
+		expr->eval_fn = eval_and;
+		expr->argv = &fake_and_arg;
+	}
+
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	struct bfs_expr *child;
+	while ((child = SLIST_POP(&children))) {
+		opt_enter(opt, "%pe\n", child);
+
+		child = negate_expr(opt, child, argv);
+		if (!child) {
+			return NULL;
+		}
+
+		opt_leave(opt, "%pe\n", child);
+		bfs_expr_append(expr, child);
+	}
+
+	opt_leave(opt, "%pe\n", expr);
+	return visit_shallow(opt, expr, &annotate);
+}
+
+/** Sink a negation into a comma expression. */
+static struct bfs_expr *sink_not_comma(struct bfs_opt *opt, struct bfs_expr *expr) {
+	bfs_assert(expr->eval_fn == eval_comma);
+
+	opt_enter(opt, "%pe\n", expr);
+
+	char **argv = expr->argv;
+	expr = only_child(expr);
+
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	struct bfs_expr *child;
+	while ((child = SLIST_POP(&children))) {
+		if (SLIST_EMPTY(&children)) {
+			opt_enter(opt, "%pe\n", child);
+			opt_debug(opt, "sink\n");
+
+			child = negate_expr(opt, child, argv);
+			if (!child) {
+				return NULL;
+			}
+
+			opt_leave(opt, "%pe\n", child);
+		} else {
+			opt_visit(opt, "%pe\n", child);
+		}
+
+		bfs_expr_append(expr, child);
+	}
+
+	opt_leave(opt, "%pe\n", expr);
+	return visit_shallow(opt, expr, &annotate);
+}
+
+/** Canonicalize a negation. */
+static struct bfs_expr *canonicalize_not(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_expr *rhs = only_child(expr);
+
+	if (rhs->eval_fn == eval_not) {
+		opt_debug(opt, "double negation\n");
+		rhs = only_child(expr);
+		return only_child(rhs);
+	} else if (rhs->eval_fn == eval_and || rhs->eval_fn == eval_or) {
+		return sink_not_andor(opt, expr);
+	} else if (rhs->eval_fn == eval_comma) {
+		return sink_not_comma(opt, expr);
+	} else if (is_const(rhs)) {
+		opt_debug(opt, "constant propagation\n");
+		return opt_const(opt, rhs->eval_fn == eval_false);
+	} else {
+		return expr;
+	}
+}
+
+/** Canonicalize an associative operator. */
+static struct bfs_expr *canonicalize_assoc(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	struct bfs_exprs flat;
+	SLIST_INIT(&flat);
+
+	struct bfs_expr *child;
+	while ((child = SLIST_POP(&children))) {
+		if (child->eval_fn == expr->eval_fn) {
+			struct bfs_expr *head = SLIST_HEAD(&child->children);
+			struct bfs_expr *tail = SLIST_TAIL(&child->children);
+
+			if (!head) {
+				opt_delete(opt, "%pe [empty]\n", child);
+			} else {
+				opt_enter(opt, "%pe\n", child);
+				opt_debug(opt, "associativity\n");
+				if (head == tail) {
+					opt_leave(opt, "%pe\n", head);
+				} else if (head->next == tail) {
+					opt_leave(opt, "%pe %pe\n", head, tail);
+				} else {
+					opt_leave(opt, "%pe ... %pe\n", head, tail);
+				}
+			}
+
+			SLIST_EXTEND(&flat, &child->children);
+		} else {
+			opt_visit(opt, "%pe\n", child);
+			SLIST_APPEND(&flat, child);
+		}
+	}
+
+	bfs_expr_extend(expr, &flat);
+
+	return visit_shallow(opt, expr, &annotate);
+}
+
+/**
+ * Canonicalizing visitor.
+ */
+static const struct visitor canonicalize = {
+	.name = "canonicalize",
+	.table = {
+		{eval_not, canonicalize_not},
+		{eval_and, canonicalize_assoc},
+		{eval_or, canonicalize_assoc},
+		{eval_comma, canonicalize_assoc},
+		{NULL, NULL},
+	},
+};
+
+/** Calculate the cost of an ordered pair of expressions. */
+static float expr_cost(const struct bfs_expr *parent, const struct bfs_expr *lhs, const struct bfs_expr *rhs) {
+	// https://cs.stackexchange.com/a/66921/21004
+	float prob = lhs->probability;
+	if (parent->eval_fn == eval_or) {
+		prob = 1.0 - prob;
+	}
+	return lhs->cost + prob * rhs->cost;
+}
+
+/** Sort a block of expressions. */
+static void sort_exprs(struct bfs_opt *opt, struct bfs_expr *parent, struct bfs_exprs *exprs) {
+	if (!exprs->head || !exprs->head->next) {
+		return;
+	}
+
+	struct bfs_exprs left, right;
+	SLIST_INIT(&left);
+	SLIST_INIT(&right);
+
+	// Split
+	for (struct bfs_expr *hare = exprs->head; hare && (hare = hare->next); hare = hare->next) {
+		struct bfs_expr *tortoise = SLIST_POP(exprs);
+		SLIST_APPEND(&left, tortoise);
+	}
+	SLIST_EXTEND(&right, exprs);
+
+	// Recurse
+	sort_exprs(opt, parent, &left);
+	sort_exprs(opt, parent, &right);
+
+	// Merge
+	while (!SLIST_EMPTY(&left) && !SLIST_EMPTY(&right)) {
+		struct bfs_expr *lhs = left.head;
+		struct bfs_expr *rhs = right.head;
+
+		float cost = expr_cost(parent, lhs, rhs);
+		float swapped = expr_cost(parent, rhs, lhs);
+
+		if (cost <= swapped) {
+			SLIST_POP(&left);
+			SLIST_APPEND(exprs, lhs);
+		} else {
+			opt_enter(opt, "%pe %pe [${ylw}%g${rs}]\n", lhs, rhs, cost);
+			SLIST_POP(&right);
+			SLIST_APPEND(exprs, rhs);
+			opt_leave(opt, "%pe %pe [${ylw}%g${rs}]\n", rhs, lhs, swapped);
+		}
+	}
+	SLIST_EXTEND(exprs, &left);
+	SLIST_EXTEND(exprs, &right);
+}
+
+/** Reorder children to reduce cost. */
+static struct bfs_expr *reorder_andor(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	// Split into blocks of consecutive pure/impure expressions, and sort
+	// the pure blocks
+	struct bfs_exprs pure;
+	SLIST_INIT(&pure);
+
+	struct bfs_expr *child;
+	while ((child = SLIST_POP(&children))) {
+		if (child->pure) {
+			SLIST_APPEND(&pure, child);
+		} else {
+			sort_exprs(opt, expr, &pure);
+			bfs_expr_extend(expr, &pure);
+			bfs_expr_append(expr, child);
+		}
+	}
+	sort_exprs(opt, expr, &pure);
+	bfs_expr_extend(expr, &pure);
+
+	return visit_shallow(opt, expr, &annotate);
+}
+
+/**
+ * Reordering visitor.
+ */
+static const struct visitor reorder = {
+	.name = "reorder",
+	.table = {
+		{eval_and, reorder_andor},
+		{eval_or, reorder_andor},
+		{NULL, NULL},
+	},
+};
+
+/** Transfer function for simple predicates. */
+static void data_flow_pred(struct bfs_opt *opt, enum pred_type pred, bool value) {
+	constrain_pred(&opt->after_true.preds[pred], value);
+	constrain_pred(&opt->after_false.preds[pred], !value);
+}
+
+/** Transfer function for icmp-style ([+-]N) expressions. */
+static void data_flow_icmp(struct bfs_opt *opt, const struct bfs_expr *expr, enum range_type type) {
+	struct df_range *true_range = &opt->after_true.ranges[type];
+	struct df_range *false_range = &opt->after_false.ranges[type];
+	long long value = expr->num;
+
+	switch (expr->int_cmp) {
+	case BFS_INT_EQUAL:
+		constrain_min(true_range, value);
+		constrain_max(true_range, value);
+		range_remove(false_range, value);
+		break;
+
+	case BFS_INT_LESS:
+		constrain_min(false_range, value);
+		constrain_max(true_range, value);
+		range_remove(true_range, value);
+		break;
+
+	case BFS_INT_GREATER:
+		constrain_max(false_range, value);
+		constrain_min(true_range, value);
+		range_remove(true_range, value);
+		break;
+	}
+}
+
+/** Transfer function for -{execut,read,writ}able. */
+static struct bfs_expr *data_flow_access(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (expr->num & R_OK) {
+		data_flow_pred(opt, READABLE_PRED, true);
+	}
+	if (expr->num & W_OK) {
+		data_flow_pred(opt, WRITABLE_PRED, true);
+	}
+	if (expr->num & X_OK) {
+		data_flow_pred(opt, EXECUTABLE_PRED, true);
 	}
 
 	return expr;
 }
 
-/** Optimize -gid. */
-static struct bfs_expr *optimize_gid(struct bfs_opt *opt, struct bfs_expr *expr) {
+/** Transfer function for -gid. */
+static struct bfs_expr *data_flow_gid(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	struct df_range *range = &opt->after_true.ranges[GID_RANGE];
 	if (range->min == range->max) {
 		gid_t gid = range->min;
 		bool nogroup = !bfs_getgrgid(opt->ctx->groups, gid);
 		if (errno == 0) {
-			opt_constrain_pred(opt, NOGROUP_PRED, nogroup);
+			data_flow_pred(opt, NOGROUP_PRED, nogroup);
 		}
 	}
 
 	return expr;
 }
 
-/** Optimize -inum. */
-static struct bfs_expr *optimize_inum(struct bfs_opt *opt, struct bfs_expr *expr) {
+/** Transfer function for -inum. */
+static struct bfs_expr *data_flow_inum(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	struct df_range *range = &opt->after_true.ranges[INUM_RANGE];
 	if (range->min == range->max) {
 		expr->probability = 0.01;
@@ -808,8 +1647,8 @@ static struct bfs_expr *optimize_inum(struct bfs_opt *opt, struct bfs_expr *expr
 	return expr;
 }
 
-/** Optimize -links. */
-static struct bfs_expr *optimize_links(struct bfs_opt *opt, struct bfs_expr *expr) {
+/** Transfer function for -links. */
+static struct bfs_expr *data_flow_links(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	struct df_range *range = &opt->after_true.ranges[LINKS_RANGE];
 	if (1 >= range->min && 1 <= range->max) {
 		expr->probability = 0.99;
@@ -820,30 +1659,20 @@ static struct bfs_expr *optimize_links(struct bfs_opt *opt, struct bfs_expr *exp
 	return expr;
 }
 
-/** Optimize -uid. */
-static struct bfs_expr *optimize_uid(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct df_range *range = &opt->after_true.ranges[UID_RANGE];
-	if (range->min == range->max) {
-		uid_t uid = range->min;
-		bool nouser = !bfs_getpwuid(opt->ctx->users, uid);
-		if (errno == 0) {
-			opt_constrain_pred(opt, NOUSER_PRED, nouser);
-		}
-	}
+/** Transfer function for -samefile. */
+static struct bfs_expr *data_flow_samefile(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct df_range *true_range = &opt->after_true.ranges[INUM_RANGE];
+	constrain_min(true_range, expr->ino);
+	constrain_max(true_range, expr->ino);
 
-	return expr;
-}
+	struct df_range *false_range = &opt->after_false.ranges[INUM_RANGE];
+	range_remove(false_range, expr->ino);
 
-/** Optimize -samefile. */
-static struct bfs_expr *optimize_samefile(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct df_range *range = &opt->after_true.ranges[INUM_RANGE];
-	constrain_min(range, expr->ino);
-	constrain_max(range, expr->ino);
 	return expr;
 }
 
-/** Optimize -size. */
-static struct bfs_expr *optimize_size(struct bfs_opt *opt, struct bfs_expr *expr) {
+/** Transfer function for -size. */
+static struct bfs_expr *data_flow_size(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	struct df_range *range = &opt->after_true.ranges[SIZE_RANGE];
 	if (range->min == range->max) {
 		expr->probability = 0.01;
@@ -854,473 +1683,449 @@ static struct bfs_expr *optimize_size(struct bfs_opt *opt, struct bfs_expr *expr
 	return expr;
 }
 
-/** Estimate probability for -x?type. */
-static void estimate_type_probability(struct bfs_expr *expr) {
-	unsigned int types = expr->num;
-
-	expr->probability = 0.0;
-	if (types & (1 << BFS_BLK)) {
-		expr->probability += 0.00000721183;
-	}
-	if (types & (1 << BFS_CHR)) {
-		expr->probability += 0.0000499855;
-	}
-	if (types & (1 << BFS_DIR)) {
-		expr->probability += 0.114475;
-	}
-	if (types & (1 << BFS_DOOR)) {
-		expr->probability += 0.000001;
-	}
-	if (types & (1 << BFS_FIFO)) {
-		expr->probability += 0.00000248684;
-	}
-	if (types & (1 << BFS_REG)) {
-		expr->probability += 0.859772;
-	}
-	if (types & (1 << BFS_LNK)) {
-		expr->probability += 0.0256816;
-	}
-	if (types & (1 << BFS_SOCK)) {
-		expr->probability += 0.0000116881;
-	}
-	if (types & (1 << BFS_WHT)) {
-		expr->probability += 0.000001;
-	}
-}
-
-/** Optimize -type. */
-static struct bfs_expr *optimize_type(struct bfs_opt *opt, struct bfs_expr *expr) {
+/** Transfer function for -type. */
+static struct bfs_expr *data_flow_type(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	opt->after_true.types &= expr->num;
 	opt->after_false.types &= ~expr->num;
-
-	estimate_type_probability(expr);
-
 	return expr;
 }
 
-/** Optimize -xtype. */
-static struct bfs_expr *optimize_xtype(struct bfs_opt *opt, struct bfs_expr *expr) {
-	if (opt->ctx->optlevel >= 4) {
-		// Since -xtype dereferences symbolic links, it may have side
-		// effects such as reporting permission errors, and thus
-		// shouldn't be re-ordered without aggressive optimizations
-		expr->pure = true;
+/** Transfer function for -uid. */
+static struct bfs_expr *data_flow_uid(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct df_range *range = &opt->after_true.ranges[UID_RANGE];
+	if (range->min == range->max) {
+		uid_t uid = range->min;
+		bool nouser = !bfs_getpwuid(opt->ctx->users, uid);
+		if (errno == 0) {
+			data_flow_pred(opt, NOUSER_PRED, nouser);
+		}
 	}
 
+	return expr;
+}
+
+/** Transfer function for -xtype. */
+static struct bfs_expr *data_flow_xtype(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
 	opt->after_true.xtypes &= expr->num;
 	opt->after_false.xtypes &= ~expr->num;
-
-	estimate_type_probability(expr);
-
 	return expr;
 }
 
-/**
- * Table of pure expressions.
- */
-static bfs_eval_fn *const opt_pure[] = {
-	eval_access,
-	eval_acl,
-	eval_capable,
-	eval_depth,
-	eval_false,
-	eval_flags,
-	eval_fstype,
-	eval_gid,
-	eval_hidden,
-	eval_inum,
-	eval_links,
-	eval_lname,
-	eval_name,
-	eval_newer,
-	eval_nogroup,
-	eval_nouser,
-	eval_path,
-	eval_perm,
-	eval_regex,
-	eval_samefile,
-	eval_size,
-	eval_sparse,
-	eval_time,
-	eval_true,
-	eval_type,
-	eval_uid,
-	eval_used,
-	eval_xattr,
-	eval_xattrname,
-};
-
-/**
- * Table of always-true expressions.
- */
-static bfs_eval_fn *const opt_always_true[] = {
-	eval_fls,
-	eval_fprint,
-	eval_fprint0,
-	eval_fprintf,
-	eval_fprintx,
-	eval_prune,
-	eval_true,
-
-	// Non-returning
-	eval_exit,
-	eval_quit,
-};
-
-/**
- * Table of always-false expressions.
- */
-static bfs_eval_fn *const opt_always_false[] = {
-	eval_false,
-
-	// Non-returning
-	eval_exit,
-	eval_quit,
-};
-
-#define FAST_COST       40.0
-#define FNMATCH_COST   400.0
-#define STAT_COST     1000.0
-#define PRINT_COST   20000.0
-
-/**
- * Table of expression costs.
- */
-static const struct {
-	/** The evaluation function with this cost. */
-	bfs_eval_fn *eval_fn;
-	/** The matching cost. */
-	float cost;
-} opt_costs[] = {
-	{eval_access,    STAT_COST},
-	{eval_acl,       STAT_COST},
-	{eval_capable,   STAT_COST},
-	{eval_empty, 2 * STAT_COST}, // readdir() is worse than stat()
-	{eval_fls,      PRINT_COST},
-	{eval_fprint,   PRINT_COST},
-	{eval_fprint0,  PRINT_COST},
-	{eval_fprintf,  PRINT_COST},
-	{eval_fprintx,  PRINT_COST},
-	{eval_fstype,    STAT_COST},
-	{eval_gid,       STAT_COST},
-	{eval_inum,      STAT_COST},
-	{eval_links,     STAT_COST},
-	{eval_lname,  FNMATCH_COST},
-	{eval_name,   FNMATCH_COST},
-	{eval_newer,     STAT_COST},
-	{eval_nogroup,   STAT_COST},
-	{eval_nouser,    STAT_COST},
-	{eval_path,   FNMATCH_COST},
-	{eval_perm,      STAT_COST},
-	{eval_samefile,  STAT_COST},
-	{eval_size,      STAT_COST},
-	{eval_sparse,    STAT_COST},
-	{eval_time,      STAT_COST},
-	{eval_uid,       STAT_COST},
-	{eval_used,      STAT_COST},
-	{eval_xattr,     STAT_COST},
-	{eval_xattrname, STAT_COST},
-};
-
-/**
- * Table of expression probabilities.
- */
-static const struct {
-	/** The evaluation function with this cost. */
-	bfs_eval_fn *eval_fn;
-	/** The matching probability. */
-	float probability;
-} opt_probs[] = {
-	{eval_acl,       0.00002},
-	{eval_capable,   0.000002},
-	{eval_empty,     0.01},
-	{eval_false,     0.0},
-	{eval_hidden,    0.01},
-	{eval_nogroup,   0.01},
-	{eval_nouser,    0.01},
-	{eval_samefile,  0.01},
-	{eval_true,      1.0},
-	{eval_xattr,     0.01},
-	{eval_xattrname, 0.01},
-};
+/** Data flow visitor entry. */
+static struct bfs_expr *data_flow_enter(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	visit_enter(opt, expr, visitor);
 
-/**
- * Table of simple predicates.
- */
-static const struct {
-	/** The evaluation function this optimizer applies to. */
-	bfs_eval_fn *eval_fn;
-	/** The corresponding predicate. */
-	enum pred_type pred;
-} opt_preds[] = {
-	{eval_acl,         ACL_PRED},
-	{eval_capable, CAPABLE_PRED},
-	{eval_empty,     EMPTY_PRED},
-	{eval_hidden,   HIDDEN_PRED},
-	{eval_nogroup, NOGROUP_PRED},
-	{eval_nouser,   NOUSER_PRED},
-	{eval_sparse,   SPARSE_PRED},
-	{eval_xattr,     XATTR_PRED},
-};
+	df_dump(opt, "before", &opt->before);
 
-/**
- * Table of simple range comparisons.
- */
-static const struct {
-	/** The evaluation function this optimizer applies to. */
-	bfs_eval_fn *eval_fn;
-	/** The corresponding range. */
-	enum range_type range;
-} opt_ranges[] = {
-	{eval_depth, DEPTH_RANGE},
-	{eval_gid,     GID_RANGE},
-	{eval_inum,   INUM_RANGE},
-	{eval_links, LINKS_RANGE},
-	{eval_size,   SIZE_RANGE},
-	{eval_uid,     UID_RANGE},
-};
+	if (!bfs_expr_is_parent(expr) && !expr->pure) {
+		df_join(opt->impure, &opt->before);
+		df_dump(opt, "impure", opt->impure);
+	}
 
-/** Signature for custom optimizer functions. */
-typedef struct bfs_expr *bfs_opt_fn(struct bfs_opt *opt, struct bfs_expr *expr);
+	return expr;
+}
 
-/** Table of custom optimizer functions. */
-static const struct {
-	/** The evaluation function this optimizer applies to. */
-	bfs_eval_fn *eval_fn;
-	/** The corresponding optimizer function. */
-	bfs_opt_fn *opt_fn;
-} opt_fns[] = {
-	// Primaries
-	{eval_access,   optimize_access},
-	{eval_empty,    optimize_empty},
-	{eval_exec,     optimize_exec},
-	{eval_gid,      optimize_gid},
-	{eval_inum,     optimize_inum},
-	{eval_links,    optimize_links},
-	{eval_lname,    optimize_fnmatch},
-	{eval_name,     optimize_fnmatch},
-	{eval_path,     optimize_fnmatch},
-	{eval_samefile, optimize_samefile},
-	{eval_size,     optimize_size},
-	{eval_type,     optimize_type},
-	{eval_uid,      optimize_uid},
-	{eval_xtype,    optimize_xtype},
-
-	// Operators
-	{eval_and,   optimize_and_expr_recursive},
-	{eval_comma, optimize_comma_expr_recursive},
-	{eval_not,   optimize_not_expr_recursive},
-	{eval_or,    optimize_or_expr_recursive},
-};
+/** Data flow visitor exit. */
+static struct bfs_expr *data_flow_leave(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (expr->always_true) {
+		expr->probability = 1.0;
+		df_init_bottom(&opt->after_false);
+	}
 
-/**
- * Look up the appropriate optimizer for an expression and call it.
- */
-static struct bfs_expr *optimize_expr_lookup(struct bfs_opt *opt, struct bfs_expr *expr) {
-	for (size_t i = 0; i < countof(opt_pure); ++i) {
-		if (opt_pure[i] == expr->eval_fn) {
-			expr->pure = true;
-			break;
-		}
+	if (expr->always_false) {
+		expr->probability = 0.0;
+		df_init_bottom(&opt->after_true);
 	}
 
-	for (size_t i = 0; i < countof(opt_always_true); ++i) {
-		if (opt_always_true[i] == expr->eval_fn) {
+	df_dump(opt, "after true", &opt->after_true);
+	df_dump(opt, "after false", &opt->after_false);
+
+	if (df_is_bottom(&opt->after_false)) {
+		if (!expr->pure) {
 			expr->always_true = true;
-			break;
+			expr->probability = 0.0;
+		} else if (expr->eval_fn != eval_true) {
+			opt_warning(opt, expr, "This expression is always true.\n\n");
+			opt_debug(opt, "pure, always true\n");
+			expr = opt_const(opt, true);
+			if (!expr) {
+				return NULL;
+			}
 		}
 	}
 
-	for (size_t i = 0; i < countof(opt_always_false); ++i) {
-		if (opt_always_false[i] == expr->eval_fn) {
+	if (df_is_bottom(&opt->after_true)) {
+		if (!expr->pure) {
 			expr->always_false = true;
-			break;
+			expr->probability = 0.0;
+		} else if (expr->eval_fn != eval_false) {
+			opt_warning(opt, expr, "This expression is always false.\n\n");
+			opt_debug(opt, "pure, always false\n");
+			expr = opt_const(opt, false);
+			if (!expr) {
+				return NULL;
+			}
 		}
 	}
 
-	expr->cost = FAST_COST;
-	for (size_t i = 0; i < countof(opt_costs); ++i) {
-		if (opt_costs[i].eval_fn == expr->eval_fn) {
-			expr->cost = opt_costs[i].cost;
-			break;
+	return visit_leave(opt, expr, visitor);
+}
+
+/** Data flow visitor function. */
+static struct bfs_expr *data_flow_visit(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (opt->ignore_result && expr->pure) {
+		opt_debug(opt, "ignored result\n");
+		opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
+		expr = opt_const(opt, false);
+		if (!expr) {
+			return NULL;
 		}
 	}
 
-	for (size_t i = 0; i < countof(opt_probs); ++i) {
-		if (opt_probs[i].eval_fn == expr->eval_fn) {
-			expr->probability = opt_probs[i].probability;
-			break;
+	if (df_is_bottom(&opt->before)) {
+		opt_debug(opt, "unreachable\n");
+		opt_warning(opt, expr, "This expression is unreachable.\n\n");
+		expr = opt_const(opt, false);
+		if (!expr) {
+			return NULL;
 		}
 	}
 
-	for (size_t i = 0; i < countof(opt_preds); ++i) {
-		if (opt_preds[i].eval_fn == expr->eval_fn) {
-			opt_constrain_pred(opt, opt_preds[i].pred, true);
+	/** Table of simple predicates. */
+	static const struct {
+		bfs_eval_fn *eval_fn;
+		enum pred_type pred;
+	} preds[] = {
+		{eval_acl,         ACL_PRED},
+		{eval_capable, CAPABLE_PRED},
+		{eval_empty,     EMPTY_PRED},
+		{eval_hidden,   HIDDEN_PRED},
+		{eval_nogroup, NOGROUP_PRED},
+		{eval_nouser,   NOUSER_PRED},
+		{eval_sparse,   SPARSE_PRED},
+		{eval_xattr,     XATTR_PRED},
+	};
+
+	for (size_t i = 0; i < countof(preds); ++i) {
+		if (preds[i].eval_fn == expr->eval_fn) {
+			data_flow_pred(opt, preds[i].pred, true);
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < countof(opt_ranges); ++i) {
-		if (opt_ranges[i].eval_fn == expr->eval_fn) {
-			optimize_icmp(opt, expr, opt_ranges[i].range);
+	/** Table of simple range comparisons. */
+	static const struct {
+		bfs_eval_fn *eval_fn;
+		enum range_type range;
+	} ranges[] = {
+		{eval_depth, DEPTH_RANGE},
+		{eval_gid,     GID_RANGE},
+		{eval_inum,   INUM_RANGE},
+		{eval_links, LINKS_RANGE},
+		{eval_size,   SIZE_RANGE},
+		{eval_uid,     UID_RANGE},
+	};
+
+	for (size_t i = 0; i < countof(ranges); ++i) {
+		if (ranges[i].eval_fn == expr->eval_fn) {
+			data_flow_icmp(opt, expr, ranges[i].range);
 			break;
 		}
 	}
 
-	for (size_t i = 0; i < countof(opt_fns); ++i) {
-		if (opt_fns[i].eval_fn == expr->eval_fn) {
-			return opt_fns[i].opt_fn(opt, expr);
-		}
+	return expr;
+}
+
+/**
+ * Data flow visitor.
+ */
+static const struct visitor data_flow = {
+	.name = "data_flow",
+	.enter = data_flow_enter,
+	.visit = data_flow_visit,
+	.leave = data_flow_leave,
+	.table = {
+		{eval_access, data_flow_access},
+		{eval_gid, data_flow_gid},
+		{eval_inum, data_flow_inum},
+		{eval_links, data_flow_links},
+		{eval_samefile, data_flow_samefile},
+		{eval_size, data_flow_size},
+		{eval_type, data_flow_type},
+		{eval_uid, data_flow_uid},
+		{eval_xtype, data_flow_xtype},
+		{NULL, NULL},
+	},
+};
+
+/** Simplify a negation. */
+static struct bfs_expr *simplify_not(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	if (opt->ignore_result) {
+		opt_debug(opt, "ignored result\n");
+		expr = only_child(expr);
 	}
 
 	return expr;
 }
 
-static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_expr *expr) {
-	int optlevel = opt->ctx->optlevel;
+/** Lift negations out of a conjunction/disjunction using De Morgan's laws. */
+static struct bfs_expr *lift_andor_not(struct bfs_opt *opt, struct bfs_expr *expr) {
+	// Only lift negations if it would reduce the number of (-not) expressions
+	size_t added = 0, removed = 0;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (child->eval_fn == eval_not) {
+			++removed;
+		} else {
+			++added;
+		}
+	}
+	if (added >= removed) {
+		return visit_shallow(opt, expr, &annotate);
+	}
 
-	opt->after_true = opt->before;
-	opt->after_false = opt->before;
+	opt_debug(opt, "De Morgan's laws\n");
 
-	if (optlevel >= 2 && df_is_bottom(&opt->before)) {
-		struct bfs_expr *ret = opt_const(opt, false);
-		opt_debug(opt, 2, "reachability: %pe --> %pe\n", expr, ret);
-		opt_warning(opt, expr, "This expression is unreachable.\n\n");
-		return ret;
+	if (expr->eval_fn == eval_and) {
+		expr->eval_fn = eval_or;
+		expr->argv = &fake_or_arg;
+	} else {
+		bfs_assert(expr->eval_fn == eval_or);
+		expr->eval_fn = eval_and;
+		expr->argv = &fake_and_arg;
+	}
+
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	struct bfs_expr *child;
+	while ((child = SLIST_POP(&children))) {
+		opt_enter(opt, "%pe\n", child);
+
+		child = negate_expr(opt, child, &fake_not_arg);
+		if (!child) {
+			return NULL;
+		}
+
+		opt_leave(opt, "%pe\n", child);
+		bfs_expr_append(expr, child);
 	}
 
-	expr = optimize_expr_lookup(opt, expr);
-	if (!expr) {
+	expr = visit_shallow(opt, expr, &annotate);
+	return negate_expr(opt, expr, &fake_not_arg);
+}
+
+/** Get the first ignorable expression in a conjunction/disjunction. */
+static struct bfs_expr *first_ignorable(struct bfs_opt *opt, struct bfs_expr *expr) {
+	if (opt->level < 2 || !opt->ignore_result) {
 		return NULL;
 	}
 
-	if (bfs_expr_is_parent(expr)) {
-		struct bfs_expr *lhs = expr->lhs;
-		struct bfs_expr *rhs = expr->rhs;
-		if (rhs) {
-			expr->persistent_fds = rhs->persistent_fds;
-			expr->ephemeral_fds = rhs->ephemeral_fds;
+	struct bfs_expr *ret = NULL;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		if (!child->pure) {
+			ret = NULL;
+		} else if (!ret) {
+			ret = child;
+		}
+	}
+
+	return ret;
+}
+
+/** Simplify a conjunction. */
+static struct bfs_expr *simplify_and(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_expr *ignorable = first_ignorable(opt, expr);
+	bool ignore = false;
+
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
+
+		if (child == ignorable) {
+			ignore = true;
+		}
+
+		if (ignore) {
+			opt_delete(opt, "%pe [ignored result]\n", child);
+			opt_warning(opt, child, "The result of this expression is ignored.\n\n");
+			continue;
+		}
+
+		if (child->eval_fn == eval_true) {
+			opt_delete(opt, "%pe [conjunction elimination]\n", child);
+			continue;
 		}
-		if (lhs) {
-			expr->persistent_fds += lhs->persistent_fds;
-			if (lhs->ephemeral_fds > expr->ephemeral_fds) {
-				expr->ephemeral_fds = lhs->ephemeral_fds;
+
+		opt_visit(opt, "%pe\n", child);
+		bfs_expr_append(expr, child);
+
+		if (child->always_false) {
+			while ((child = SLIST_POP(&children))) {
+				opt_delete(opt, "%pe [short-circuit]\n", child);
 			}
 		}
-	} else if (!expr->pure) {
-		df_join(opt->impure, &opt->before);
 	}
 
-	if (expr->always_true) {
-		expr->probability = 1.0;
-		df_init_bottom(&opt->after_false);
-	}
-	if (expr->always_false) {
-		expr->probability = 0.0;
-		df_init_bottom(&opt->after_true);
+	struct bfs_expr *child = bfs_expr_children(expr);
+	if (!child) {
+		opt_debug(opt, "nullary identity\n");
+		return opt_const(opt, true);
+	} else if (!child->next) {
+		opt_debug(opt, "unary identity\n");
+		return only_child(expr);
 	}
 
-	if (optlevel < 2 || expr->eval_fn == eval_true || expr->eval_fn == eval_false) {
-		return expr;
-	}
+	return lift_andor_not(opt, expr);
+}
 
-	if (df_is_bottom(&opt->after_true)) {
-		if (expr->pure) {
-			struct bfs_expr *ret = opt_const(opt, false);
-			opt_warning(opt, expr, "This expression is always false.\n\n");
-			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
-			return ret;
-		} else {
-			expr->always_false = true;
-			expr->probability = 0.0;
+/** Simplify a disjunction. */
+static struct bfs_expr *simplify_or(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_expr *ignorable = first_ignorable(opt, expr);
+	bool ignore = false;
+
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
+
+		if (child == ignorable) {
+			ignore = true;
 		}
-	} else if (df_is_bottom(&opt->after_false)) {
-		if (expr->pure) {
-			struct bfs_expr *ret = opt_const(opt, true);
-			opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
-			opt_warning(opt, expr, "This expression is always true.\n\n");
-			return ret;
-		} else {
-			expr->always_true = true;
-			expr->probability = 1.0;
+
+		if (ignore) {
+			opt_delete(opt, "%pe [ignored result]\n", child);
+			opt_warning(opt, child, "The result of this expression is ignored.\n\n");
+			continue;
 		}
-	}
 
-	return expr;
-}
+		if (child->eval_fn == eval_false) {
+			opt_delete(opt, "%pe [disjunctive syllogism]\n", child);
+			continue;
+		}
 
-/** Swap the children of a binary expression if it would reduce the cost. */
-static bool reorder_expr(const struct bfs_opt *opt, struct bfs_expr *expr, float swapped_cost) {
-	if (swapped_cost < expr->cost) {
-		bool debug = opt_debug(opt, 3, "cost: %pe <==> ", expr);
-		struct bfs_expr *lhs = expr->lhs;
-		expr->lhs = expr->rhs;
-		expr->rhs = lhs;
-		if (debug) {
-			cfprintf(opt->ctx->cerr, "%pe (~${ylw}%g${rs} --> ~${ylw}%g${rs})\n", expr, expr->cost, swapped_cost);
+		opt_visit(opt, "%pe\n", child);
+		bfs_expr_append(expr, child);
+
+		if (child->always_true) {
+			while ((child = SLIST_POP(&children))) {
+				opt_delete(opt, "%pe [short-circuit]\n", child);
+			}
 		}
-		expr->cost = swapped_cost;
-		return true;
-	} else {
-		return false;
 	}
-}
 
-/**
- * Recursively reorder sub-expressions to reduce the overall cost.
- *
- * @param expr
- *         The expression to optimize.
- * @return
- *         Whether any subexpression was reordered.
- */
-static bool reorder_expr_recursive(const struct bfs_opt *opt, struct bfs_expr *expr) {
-	if (!bfs_expr_is_parent(expr)) {
-		return false;
+	struct bfs_expr *child = bfs_expr_children(expr);
+	if (!child) {
+		opt_debug(opt, "nullary identity\n");
+		return opt_const(opt, false);
+	} else if (!child->next) {
+		opt_debug(opt, "unary identity\n");
+		return only_child(expr);
 	}
 
-	struct bfs_expr *lhs = expr->lhs;
-	struct bfs_expr *rhs = expr->rhs;
+	return lift_andor_not(opt, expr);
+}
 
-	bool ret = false;
-	if (lhs) {
-		ret |= reorder_expr_recursive(opt, lhs);
-	}
-	if (rhs) {
-		ret |= reorder_expr_recursive(opt, rhs);
-	}
+/** Simplify a comma expression. */
+static struct bfs_expr *simplify_comma(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	struct bfs_exprs children;
+	foster_children(expr, &children);
+
+	while (!SLIST_EMPTY(&children)) {
+		struct bfs_expr *child = SLIST_POP(&children);
 
-	if (expr->eval_fn == eval_and || expr->eval_fn == eval_or) {
-		if (lhs->pure && rhs->pure) {
-			float rhs_prob = expr->eval_fn == eval_and ? rhs->probability : 1.0 - rhs->probability;
-			float swapped_cost = rhs->cost + rhs_prob * lhs->cost;
-			ret |= reorder_expr(opt, expr, swapped_cost);
+		if (opt->level >= 2 && child->pure && !SLIST_EMPTY(&children)) {
+			opt_delete(opt, "%pe [ignored result]\n", child);
+			opt_warning(opt, child, "The result of this expression is ignored.\n\n");
+			continue;
 		}
+
+		opt_visit(opt, "%pe\n", child);
+		bfs_expr_append(expr, child);
 	}
 
-	return ret;
+	struct bfs_expr *child = bfs_expr_children(expr);
+	if (child && !child->next) {
+		opt_debug(opt, "unary identity\n");
+		return only_child(expr);
+	}
+
+	return expr;
 }
 
 /**
- * Optimize a top-level expression.
+ * Logical simplification visitor.
  */
-static struct bfs_expr *optimize_expr(struct bfs_opt *opt, struct bfs_expr *expr) {
-	struct df_domain saved_impure = *opt->impure;
+static const struct visitor simplify = {
+	.name = "simplify",
+	.table = {
+		{eval_not, simplify_not},
+		{eval_and, simplify_and},
+		{eval_or, simplify_or},
+		{eval_comma, simplify_comma},
+		{NULL, NULL},
+	},
+};
 
-	expr = optimize_expr_recursive(opt, expr);
-	if (!expr) {
-		return NULL;
-	}
+/** Optimize an expression. */
+static struct bfs_expr *optimize(struct bfs_opt *opt, struct bfs_expr *expr) {
+	opt_enter(opt, "pass 0:\n");
+	expr = visit(opt, expr, &annotate);
+	opt_leave(opt, NULL);
+
+	/** Table of optimization passes. */
+	static const struct {
+		/** Minimum optlevel for this pass. */
+		int level;
+		/** The visitor for this pass. */
+		const struct visitor *visitor;
+	} passes[] = {
+		{1, &canonicalize},
+		{3, &reorder},
+		{2, &data_flow},
+		{1, &simplify},
+	};
 
-	if (opt->ctx->optlevel >= 3 && reorder_expr_recursive(opt, expr)) {
-		// Re-do optimizations to account for the new ordering
-		*opt->impure = saved_impure;
-		expr = optimize_expr_recursive(opt, expr);
-		if (!expr) {
-			return NULL;
+	struct df_domain impure;
+
+	for (int i = 0; i < 3; ++i) {
+		struct bfs_opt nested = *opt;
+		nested.impure = &impure;
+		impure = *opt->impure;
+
+		opt_enter(&nested, "pass %d:\n", i + 1);
+
+		for (size_t j = 0; j < countof(passes); ++j) {
+			if (opt->level < passes[j].level) {
+				continue;
+			}
+
+			// Skip reordering the first time through the passes, to
+			// make warnings more understandable
+			if (passes[j].visitor == &reorder) {
+				if (i == 0) {
+					continue;
+				} else {
+					nested.warn = false;
+				}
+			}
+
+			expr = visit(&nested, expr, passes[j].visitor);
+			if (!expr) {
+				return NULL;
+			}
+		}
+
+		opt_leave(&nested, NULL);
+
+		if (!bfs_expr_is_parent(expr)) {
+			break;
 		}
 	}
 
+	*opt->impure = impure;
 	return expr;
 }
 
@@ -1332,30 +2137,37 @@ int bfs_optimize(struct bfs_ctx *ctx) {
 
 	struct bfs_opt opt = {
 		.ctx = ctx,
+		.level = ctx->optlevel,
+		.depth = 0,
+		.warn = ctx->warn,
+		.ignore_result = false,
 		.impure = &impure,
 	};
 	df_init_top(&opt.before);
 
-	ctx->exclude = optimize_expr(&opt, ctx->exclude);
+	ctx->exclude = optimize(&opt, ctx->exclude);
 	if (!ctx->exclude) {
 		return -1;
 	}
 
 	// Only non-excluded files are evaluated
 	opt.before = opt.after_false;
+	opt.ignore_result = true;
 
 	struct df_range *depth = &opt.before.ranges[DEPTH_RANGE];
-	constrain_min(depth, ctx->mindepth);
-	constrain_max(depth, ctx->maxdepth);
+	if (ctx->mindepth > 0) {
+		constrain_min(depth, ctx->mindepth);
+	}
+	if (ctx->maxdepth < INT_MAX) {
+		constrain_max(depth, ctx->maxdepth);
+	}
 
-	ctx->expr = optimize_expr(&opt, ctx->expr);
+	ctx->expr = optimize(&opt, ctx->expr);
 	if (!ctx->expr) {
 		return -1;
 	}
 
-	ctx->expr = ignore_result(&opt, ctx->expr);
-
-	if (df_is_bottom(&impure)) {
+	if (opt.level >= 2 && df_is_bottom(&impure)) {
 		bfs_warning(ctx, "This command won't do anything.\n\n");
 	}
 
@@ -1363,23 +2175,27 @@ int bfs_optimize(struct bfs_ctx *ctx) {
 	long long mindepth = impure_depth->min;
 	long long maxdepth = impure_depth->max;
 
-	int optlevel = ctx->optlevel;
+	opt_enter(&opt, "post-process:\n");
 
-	if (optlevel >= 2 && mindepth > ctx->mindepth) {
+	if (opt.level >= 2 && mindepth > ctx->mindepth) {
 		if (mindepth > INT_MAX) {
 			mindepth = INT_MAX;
 		}
+		opt_enter(&opt, "${blu}-mindepth${rs} ${bld}%d${rs}\n", ctx->mindepth);
 		ctx->mindepth = mindepth;
-		opt_debug(&opt, 2, "data flow: mindepth --> %d\n", ctx->mindepth);
+		opt_leave(&opt, "${blu}-mindepth${rs} ${bld}%d${rs}\n", ctx->mindepth);
 	}
 
-	if (optlevel >= 4 && maxdepth < ctx->maxdepth) {
+	if (opt.level >= 4 && maxdepth < ctx->maxdepth) {
 		if (maxdepth < INT_MIN) {
 			maxdepth = INT_MIN;
 		}
+		opt_enter(&opt, "${blu}-maxdepth${rs} ${bld}%d${rs}\n", ctx->maxdepth);
 		ctx->maxdepth = maxdepth;
-		opt_debug(&opt, 4, "data flow: maxdepth --> %d\n", ctx->maxdepth);
+		opt_leave(&opt, "${blu}-maxdepth${rs} ${bld}%d${rs}\n", ctx->maxdepth);
 	}
 
+	opt_leave(&opt, NULL);
+
 	return 0;
 }
diff --git a/src/parse.c b/src/parse.c
index 17fe8ad..4212196 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -21,6 +21,7 @@
 #include "exec.h"
 #include "expr.h"
 #include "fsade.h"
+#include "list.h"
 #include "opt.h"
 #include "printf.h"
 #include "pwcache.h"
@@ -47,10 +48,9 @@
 #include <unistd.h>
 
 // Strings printed by -D tree for "fake" expressions
-static char *fake_and_arg = "-a";
-static char *fake_false_arg = "-false";
+static char *fake_and_arg = "-and";
 static char *fake_hidden_arg = "-hidden";
-static char *fake_or_arg = "-o";
+static char *fake_or_arg = "-or";
 static char *fake_print_arg = "-print";
 static char *fake_true_arg = "-true";
 
@@ -319,12 +319,8 @@ static struct bfs_expr *new_unary_expr(const struct bfs_parser *parser, bfs_eval
 		return NULL;
 	}
 
-	expr->lhs = NULL;
-	expr->rhs = rhs;
 	bfs_assert(bfs_expr_is_parent(expr));
-
-	expr->persistent_fds = rhs->persistent_fds;
-	expr->ephemeral_fds = rhs->ephemeral_fds;
+	bfs_expr_append(expr, rhs);
 	return expr;
 }
 
@@ -337,17 +333,9 @@ static struct bfs_expr *new_binary_expr(const struct bfs_parser *parser, bfs_eva
 		return NULL;
 	}
 
-	expr->lhs = lhs;
-	expr->rhs = rhs;
 	bfs_assert(bfs_expr_is_parent(expr));
-
-	expr->persistent_fds = lhs->persistent_fds + rhs->persistent_fds;
-	if (lhs->ephemeral_fds > rhs->ephemeral_fds) {
-		expr->ephemeral_fds = lhs->ephemeral_fds;
-	} else {
-		expr->ephemeral_fds = rhs->ephemeral_fds;
-	}
-
+	bfs_expr_append(expr, lhs);
+	bfs_expr_append(expr, rhs);
 	return expr;
 }
 
@@ -774,19 +762,6 @@ static struct bfs_expr *parse_unary_action(struct bfs_parser *parser, bfs_eval_f
 	return parse_action(parser, eval_fn, 2);
 }
 
-/**
- * Add an expression to the exclusions.
- */
-static int parse_exclude(struct bfs_parser *parser, struct bfs_expr *expr) {
-	struct bfs_ctx *ctx = parser->ctx;
-	ctx->exclude = new_binary_expr(parser, eval_or, ctx->exclude, expr, &fake_or_arg);
-	if (ctx->exclude) {
-		return 0;
-	} else {
-		return -1;
-	}
-}
-
 /**
  * Parse a test expression with integer data and a comparison flag.
  */
@@ -1839,10 +1814,7 @@ static struct bfs_expr *parse_nohidden(struct bfs_parser *parser, int arg1, int
 		return NULL;
 	}
 
-	if (parse_exclude(parser, hidden) != 0) {
-		return NULL;
-	}
-
+	bfs_expr_append(parser->ctx->exclude, hidden);
 	return parse_nullary_option(parser);
 }
 
@@ -3206,10 +3178,7 @@ static struct bfs_expr *parse_factor(struct bfs_parser *parser) {
 
 		parser->excluding = false;
 
-		if (parse_exclude(parser, factor) != 0) {
-			return NULL;
-		}
-
+		bfs_expr_append(parser->ctx->exclude, factor);
 		return parse_new_expr(parser, eval_true, parser->argv - argv, argv);
 	} else if (strcmp(arg, "!") == 0 || strcmp(arg, "-not") == 0) {
 		char **argv = parser_advance(parser, T_OPERATOR, 1);
@@ -3428,19 +3397,29 @@ static void dump_expr_multiline(const struct bfs_ctx *ctx, enum debug_flags flag
 		cfprintf(ctx->cerr, "  ");
 	}
 
+	bool close = true;
+
 	if (bfs_expr_is_parent(expr)) {
-		cfprintf(ctx->cerr, "(${red}%s${rs}\n", expr->argv[0]);
-		if (expr->lhs) {
-			dump_expr_multiline(ctx, flag, expr->lhs, indent + 1, 0);
+		if (SLIST_EMPTY(&expr->children)) {
+			cfprintf(ctx->cerr, "(${red}%s${rs}", expr->argv[0]);
+			++rparens;
+		} else {
+			cfprintf(ctx->cerr, "(${red}%s${rs}\n", expr->argv[0]);
+			for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+				int parens = child->next ? 0 : rparens + 1;
+				dump_expr_multiline(ctx, flag, child, indent + 1, parens);
+			}
+			close = false;
 		}
-		dump_expr_multiline(ctx, flag, expr->rhs, indent + 1, rparens + 1);
 	} else {
 		if (flag == DEBUG_RATES) {
 			cfprintf(ctx->cerr, "%pE", expr);
 		} else {
 			cfprintf(ctx->cerr, "%pe", expr);
 		}
+	}
 
+	if (close) {
 		for (int i = 0; i < rparens; ++i) {
 			cfprintf(ctx->cerr, ")");
 		}
@@ -3540,10 +3519,8 @@ void bfs_ctx_dump(const struct bfs_ctx *ctx, enum debug_flags flag) {
 
 	fputs("\n", stderr);
 
-	if (ctx->exclude->eval_fn != eval_false) {
-		bfs_debug(ctx, flag, "(${red}-exclude${rs}\n");
-		dump_expr_multiline(ctx, flag, ctx->exclude, 1, 1);
-	}
+	bfs_debug(ctx, flag, "(${red}-exclude${rs}\n");
+	dump_expr_multiline(ctx, flag, ctx->exclude, 1, 1);
 
 	dump_expr_multiline(ctx, flag, ctx->expr, 0, 0);
 }
@@ -3638,7 +3615,7 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 		.now = ctx->now,
 	};
 
-	ctx->exclude = parse_new_expr(&parser, eval_false, 1, &fake_false_arg);
+	ctx->exclude = parse_new_expr(&parser, eval_or, 1, &fake_or_arg);
 	if (!ctx->exclude) {
 		goto fail;
 	}
-- 
cgit v1.2.3


From a726c7128ab5c6fffeb6844f3d819ada0369e6a8 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 31 Jan 2024 19:51:51 -0500
Subject: opt: Charge eval_flags() for a stat() call

---
 src/opt.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index 7203c61..28a2255 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1218,6 +1218,7 @@ static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *exp
 		{eval_acl,       STAT_COST},
 		{eval_capable,   STAT_COST},
 		{eval_empty, 2 * STAT_COST}, // readdir() is worse than stat()
+		{eval_flags,     STAT_COST},
 		{eval_fls,      PRINT_COST},
 		{eval_fprint,   PRINT_COST},
 		{eval_fprint0,  PRINT_COST},
-- 
cgit v1.2.3


From 5f0958fa57770e13b8696b8ee6fc87890333d90b Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Mon, 5 Feb 2024 15:13:38 -0500
Subject: opt: Enable BFTW_STAT when profitable

---
 src/expr.h |  2 ++
 src/opt.c  | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)

(limited to 'src/opt.c')

diff --git a/src/expr.h b/src/expr.h
index 4d607a4..349e052 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -110,6 +110,8 @@ struct bfs_expr {
 	bool always_true;
 	/** Whether this expression always evaluates to false. */
 	bool always_false;
+	/** Whether this expression uses stat(). */
+	bool calls_stat;
 
 	/** Estimated cost. */
 	float cost;
diff --git a/src/opt.c b/src/opt.c
index 28a2255..74145ac 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1004,6 +1004,13 @@ static struct bfs_expr *annotate_fnmatch(struct bfs_opt *opt, struct bfs_expr *e
 	return expr;
 }
 
+/** Annotate -f?print. */
+static struct bfs_expr *annotate_fprint(struct bfs_opt *opt, struct bfs_expr *expr, const struct visitor *visitor) {
+	const struct colors *colors = expr->cfile->colors;
+	expr->calls_stat = colors && colors_need_stat(colors);
+	return expr;
+}
+
 /** Estimate probability for -x?type. */
 static void estimate_type_probability(struct bfs_expr *expr) {
 	unsigned int types = expr->num;
@@ -1204,6 +1211,38 @@ static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *exp
 		}
 	}
 
+	/** Table of stat-calling primaries. */
+	static bfs_eval_fn *const calls_stat[] = {
+		eval_empty,
+		eval_flags,
+		eval_fls,
+		eval_fprintf,
+		eval_fstype,
+		eval_gid,
+		eval_inum,
+		eval_links,
+		eval_newer,
+		eval_nogroup,
+		eval_nouser,
+		eval_perm,
+		eval_samefile,
+		eval_size,
+		eval_sparse,
+		eval_time,
+		eval_uid,
+		eval_used,
+		eval_xattr,
+		eval_xattrname,
+	};
+
+	expr->calls_stat = false;
+	for (size_t i = 0; i < countof(calls_stat); ++i) {
+		if (expr->eval_fn == calls_stat[i]) {
+			expr->calls_stat = true;
+			break;
+		}
+	}
+
 #define FAST_COST       40.0
 #define FNMATCH_COST   400.0
 #define STAT_COST     1000.0
@@ -1294,6 +1333,7 @@ static const struct visitor annotate = {
 		{eval_access, annotate_access},
 		{eval_empty, annotate_empty},
 		{eval_exec, annotate_exec},
+		{eval_fprint, annotate_fprint},
 		{eval_lname, annotate_fnmatch},
 		{eval_name, annotate_fnmatch},
 		{eval_path, annotate_fnmatch},
@@ -2130,6 +2170,43 @@ static struct bfs_expr *optimize(struct bfs_opt *opt, struct bfs_expr *expr) {
 	return expr;
 }
 
+/** Estimate the odds of an expression calling stat(). */
+static float expr_stat_odds(struct bfs_expr *expr) {
+	if (expr->calls_stat) {
+		return 1.0;
+	}
+
+	float nostat_odds = 1.0;
+	float reached_odds = 1.0;
+	for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) {
+		float child_odds = expr_stat_odds(child);
+		nostat_odds *= 1.0 - reached_odds * child_odds;
+
+		if (expr->eval_fn == eval_and) {
+			reached_odds *= child->probability;
+		} else if (expr->eval_fn == eval_or) {
+			reached_odds *= 1.0 - child->probability;
+		}
+	}
+
+	return 1.0 - nostat_odds;
+}
+
+/** Estimate the odds of calling stat(). */
+static float estimate_stat_odds(struct bfs_ctx *ctx) {
+	if (ctx->unique) {
+		return 1.0;
+	}
+
+	float nostat_odds = 1.0 - expr_stat_odds(ctx->exclude);
+
+	float reached_odds = 1.0 - ctx->exclude->probability;
+	float expr_odds = expr_stat_odds(ctx->expr);
+	nostat_odds *= 1.0 - reached_odds * expr_odds;
+
+	return 1.0 - nostat_odds;
+}
+
 int bfs_optimize(struct bfs_ctx *ctx) {
 	bfs_ctx_dump(ctx, DEBUG_OPT);
 
@@ -2196,6 +2273,20 @@ int bfs_optimize(struct bfs_ctx *ctx) {
 		opt_leave(&opt, "${blu}-maxdepth${rs} ${bld}%d${rs}\n", ctx->maxdepth);
 	}
 
+	if (opt.level >= 3) {
+		// bfs_eval() can do lazy stat() calls, but only on one thread.
+		float lazy_cost = estimate_stat_odds(ctx);
+		// bftw() can do eager stat() calls in parallel
+		float eager_cost = 1.0 / ctx->threads;
+
+		if (eager_cost <= lazy_cost) {
+			opt_enter(&opt, "lazy stat cost: ${ylw}%g${rs}\n", lazy_cost);
+			ctx->flags |= BFTW_STAT;
+			opt_leave(&opt, "eager stat cost: ${ylw}%g${rs}\n", eager_cost);
+		}
+
+	}
+
 	opt_leave(&opt, NULL);
 
 	return 0;
-- 
cgit v1.2.3


From 2c3ef3a06ee1f951f6d68be6d0d3f6a1822b05b7 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Mon, 11 Mar 2024 09:51:03 -0400
Subject: Re-run include-what-you-use

---
 src/alloc.h    | 1 +
 src/bfstd.c    | 6 +++---
 src/bftw.c     | 1 +
 src/color.h    | 1 -
 src/ctx.c      | 1 +
 src/ctx.h      | 2 ++
 src/diag.c     | 2 +-
 src/dir.h      | 4 ++--
 src/dstring.c  | 2 ++
 src/eval.c     | 4 ++--
 src/expr.c     | 4 ++--
 src/expr.h     | 1 -
 src/ioq.c      | 5 +++--
 src/main.c     | 1 +
 src/opt.c      | 3 ++-
 src/parse.c    | 3 +--
 src/printf.c   | 3 ++-
 src/trie.c     | 2 --
 src/trie.h     | 1 -
 src/xspawn.c   | 1 -
 src/xtime.c    | 1 -
 tests/alloc.c  | 1 +
 tests/bfstd.c  | 3 ---
 tests/bit.c    | 2 +-
 tests/ioq.c    | 2 ++
 tests/main.c   | 3 ---
 tests/xtime.c  | 4 ++--
 tests/xtouch.c | 1 +
 28 files changed, 33 insertions(+), 32 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/alloc.h b/src/alloc.h
index 60dd738..ae055bc 100644
--- a/src/alloc.h
+++ b/src/alloc.h
@@ -10,6 +10,7 @@
 
 #include "config.h"
 #include <errno.h>
+#include <stddef.h>
 #include <stdlib.h>
 
 /** Check if a size is properly aligned. */
diff --git a/src/bfstd.c b/src/bfstd.c
index ce4aa49..c6c2e7f 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -2,18 +2,19 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "bfstd.h"
-#include "bit.h"
 #include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include "thread.h"
 #include "xregex.h"
-#include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <langinfo.h>
+#include <limits.h>
 #include <locale.h>
 #include <nl_types.h>
+#include <pthread.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -24,7 +25,6 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <wchar.h>
-#include <wctype.h>
 
 #if BFS_USE_SYS_SYSMACROS_H
 #  include <sys/sysmacros.h>
diff --git a/src/bftw.c b/src/bftw.c
index 6f52299..50b8b02 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -35,6 +35,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 
 /** Initialize a bftw_stat cache. */
 static void bftw_stat_init(struct bftw_stat *bufs, struct bfs_stat *stat_buf, struct bfs_stat *lstat_buf) {
diff --git a/src/color.h b/src/color.h
index 85633a4..e3e7973 100644
--- a/src/color.h
+++ b/src/color.h
@@ -10,7 +10,6 @@
 
 #include "config.h"
 #include "dstring.h"
-#include <stdarg.h>
 #include <stdio.h>
 
 /**
diff --git a/src/ctx.c b/src/ctx.c
index 6c84f75..f5b28c7 100644
--- a/src/ctx.c
+++ b/src/ctx.c
@@ -6,6 +6,7 @@
 #include "color.h"
 #include "diag.h"
 #include "expr.h"
+#include "list.h"
 #include "mtab.h"
 #include "pwcache.h"
 #include "stat.h"
diff --git a/src/ctx.h b/src/ctx.h
index aa91f2c..e14db21 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -18,6 +18,8 @@
 #include <sys/resource.h>
 #include <time.h>
 
+struct CFILE;
+
 /**
  * The execution context for bfs.
  */
diff --git a/src/diag.c b/src/diag.c
index 656fa89..cb27b92 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -11,8 +11,8 @@
 #include "expr.h"
 #include <errno.h>
 #include <stdarg.h>
+#include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 
 /** bfs_diagf() implementation. */
 attr(printf(2, 0))
diff --git a/src/dir.h b/src/dir.h
index b11d454..18d907e 100644
--- a/src/dir.h
+++ b/src/dir.h
@@ -8,8 +8,6 @@
 #ifndef BFS_DIR_H
 #define BFS_DIR_H
 
-#include "alloc.h"
-#include "config.h"
 #include <sys/types.h>
 
 /**
@@ -78,6 +76,8 @@ struct bfs_dirent {
  */
 struct bfs_dir *bfs_allocdir(void);
 
+struct arena;
+
 /**
  * Initialize an arena for directories.
  *
diff --git a/src/dstring.c b/src/dstring.c
index bc18308..10b0fad 100644
--- a/src/dstring.c
+++ b/src/dstring.c
@@ -7,6 +7,8 @@
 #include "config.h"
 #include "diag.h"
 #include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/eval.c b/src/eval.c
index 1711001..9e55964 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -25,7 +25,6 @@
 #include "stat.h"
 #include "trie.h"
 #include "xregex.h"
-#include "xtime.h"
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ -36,8 +35,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <sys/resource.h>
-#include <sys/stat.h>
+#include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
 #include <wchar.h>
diff --git a/src/expr.c b/src/expr.c
index 3e0033f..5784220 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4,12 +4,12 @@
 #include "expr.h"
 #include "alloc.h"
 #include "ctx.h"
+#include "diag.h"
 #include "eval.h"
 #include "exec.h"
+#include "list.h"
 #include "printf.h"
 #include "xregex.h"
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 struct bfs_expr *bfs_expr_new(struct bfs_ctx *ctx, bfs_eval_fn *eval_fn, size_t argc, char **argv) {
diff --git a/src/expr.h b/src/expr.h
index 957b04a..75cb5fd 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -12,7 +12,6 @@
 #include "config.h"
 #include "eval.h"
 #include "stat.h"
-#include <stddef.h>
 #include <sys/types.h>
 #include <time.h>
 
diff --git a/src/ioq.c b/src/ioq.c
index 00c3b86..37eed7d 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -126,13 +126,14 @@
 #include "config.h"
 #include "diag.h"
 #include "dir.h"
-#include "sanity.h"
 #include "stat.h"
 #include "thread.h"
-#include <assert.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <pthread.h>
+#include <stdint.h>
 #include <stdlib.h>
+#include <sys/stat.h>
 
 #if BFS_USE_LIBURING
 #  include <liburing.h>
diff --git a/src/main.c b/src/main.c
index 16a2576..e120f03 100644
--- a/src/main.c
+++ b/src/main.c
@@ -48,6 +48,7 @@
 #include "bfstd.h"
 #include "config.h"
 #include "ctx.h"
+#include "diag.h"
 #include "eval.h"
 #include "parse.h"
 #include <errno.h>
diff --git a/src/opt.c b/src/opt.c
index 74145ac..76965de 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -26,11 +26,13 @@
  */
 
 #include "opt.h"
+#include "bftw.h"
 #include "bit.h"
 #include "color.h"
 #include "config.h"
 #include "ctx.h"
 #include "diag.h"
+#include "dir.h"
 #include "eval.h"
 #include "exec.h"
 #include "expr.h"
@@ -40,7 +42,6 @@
 #include <limits.h>
 #include <stdarg.h>
 #include <stdio.h>
-#include <string.h>
 #include <unistd.h>
 
 static char *fake_and_arg = "-and";
diff --git a/src/parse.c b/src/parse.c
index b26a50f..3b7386d 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -42,8 +42,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
-#include <sys/time.h>
-#include <sys/wait.h>
+#include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
 
diff --git a/src/printf.c b/src/printf.c
index 34ed606..487f039 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: 0BSD
 
 #include "printf.h"
+#include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
 #include "color.h"
@@ -14,10 +15,10 @@
 #include "mtab.h"
 #include "pwcache.h"
 #include "stat.h"
-#include "xtime.h"
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
+#include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/src/trie.c b/src/trie.c
index bd5300d..1ffb23a 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -87,9 +87,7 @@
 #include "config.h"
 #include "diag.h"
 #include "list.h"
-#include <limits.h>
 #include <stdint.h>
-#include <stdlib.h>
 #include <string.h>
 
 bfs_static_assert(CHAR_WIDTH == 8);
diff --git a/src/trie.h b/src/trie.h
index 02088f1..4288d76 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -5,7 +5,6 @@
 #define BFS_TRIE_H
 
 #include "alloc.h"
-#include "config.h"
 #include "list.h"
 #include <stddef.h>
 #include <stdint.h>
diff --git a/src/xspawn.c b/src/xspawn.c
index 8d6108b..6a94d3d 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -12,7 +12,6 @@
 #include <string.h>
 #include <sys/resource.h>
 #include <sys/types.h>
-#include <sys/wait.h>
 #include <unistd.h>
 
 #if BFS_USE_PATHS_H
diff --git a/src/xtime.c b/src/xtime.c
index 05f0e1a..5b259ab 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -7,7 +7,6 @@
 #include "diag.h"
 #include <errno.h>
 #include <limits.h>
-#include <stdlib.h>
 #include <sys/time.h>
 #include <time.h>
 #include <unistd.h>
diff --git a/tests/alloc.c b/tests/alloc.c
index 4ce23d4..9f08111 100644
--- a/tests/alloc.c
+++ b/tests/alloc.c
@@ -3,6 +3,7 @@
 
 #include "tests.h"
 #include "../src/alloc.h"
+#include "../src/config.h"
 #include "../src/diag.h"
 #include <errno.h>
 #include <stdlib.h>
diff --git a/tests/bfstd.c b/tests/bfstd.c
index 0ded5de..26abdb6 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -7,9 +7,6 @@
 #include "../src/diag.h"
 #include <errno.h>
 #include <langinfo.h>
-#include <locale.h>
-#include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/tests/bit.c b/tests/bit.c
index b944748..3d66ce3 100644
--- a/tests/bit.c
+++ b/tests/bit.c
@@ -3,10 +3,10 @@
 
 #include "tests.h"
 #include "../src/bit.h"
+#include "../src/config.h"
 #include "../src/diag.h"
 #include <limits.h>
 #include <stdint.h>
-#include <stdlib.h>
 
 bfs_static_assert(UMAX_WIDTH(0x1) == 1);
 bfs_static_assert(UMAX_WIDTH(0x3) == 2);
diff --git a/tests/ioq.c b/tests/ioq.c
index 56e1886..1ce8f75 100644
--- a/tests/ioq.c
+++ b/tests/ioq.c
@@ -4,10 +4,12 @@
 #include "tests.h"
 #include "../src/ioq.h"
 #include "../src/bfstd.h"
+#include "../src/config.h"
 #include "../src/diag.h"
 #include "../src/dir.h"
 #include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
 
 /**
  * Test for blocking within ioq_slot_push().
diff --git a/tests/main.c b/tests/main.c
index 38438b2..8849e8c 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -6,11 +6,8 @@
  */
 
 #include "tests.h"
-#include "../src/bfstd.h"
 #include "../src/color.h"
 #include "../src/config.h"
-#include "../src/diag.h"
-#include <errno.h>
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/tests/xtime.c b/tests/xtime.c
index 3f1fec2..c8dc00b 100644
--- a/tests/xtime.c
+++ b/tests/xtime.c
@@ -5,10 +5,10 @@
 #include "../src/xtime.h"
 #include "../src/bfstd.h"
 #include "../src/config.h"
+#include "../src/diag.h"
 #include <errno.h>
+#include <limits.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <time.h>
 
 static bool tm_equal(const struct tm *tma, const struct tm *tmb) {
diff --git a/tests/xtouch.c b/tests/xtouch.c
index 8c5c5f3..fad272f 100644
--- a/tests/xtouch.c
+++ b/tests/xtouch.c
@@ -11,6 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <time.h>
 #include <unistd.h>
 
-- 
cgit v1.2.3


From 912d2b94cf6ff0871c07325af5ed520a2bc97722 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 20 Mar 2024 10:44:34 -0400
Subject: Implement -limit N

Closes: https://github.com/tavianator/bfs/issues/133
---
 completions/bfs.bash              |  3 +--
 completions/bfs.fish              |  1 +
 completions/bfs.zsh               |  1 +
 docs/USAGE.md                     | 34 ++++++++++++++++++++++++++++++++++
 docs/bfs.1                        |  5 +++++
 src/eval.c                        | 13 +++++++++++++
 src/eval.h                        |  1 +
 src/opt.c                         |  1 +
 src/parse.c                       | 38 +++++++++++++++++++++++++++++++++++++-
 tests/bfs/limit.out               |  4 ++++
 tests/bfs/limit.sh                |  1 +
 tests/bfs/limit_0.sh              |  1 +
 tests/bfs/limit_implicit_print.sh |  1 +
 tests/bfs/limit_incomplete.sh     |  1 +
 tests/bfs/limit_one.sh            |  1 +
 15 files changed, 103 insertions(+), 3 deletions(-)
 create mode 100644 tests/bfs/limit.out
 create mode 100644 tests/bfs/limit.sh
 create mode 100644 tests/bfs/limit_0.sh
 create mode 100644 tests/bfs/limit_implicit_print.sh
 create mode 100644 tests/bfs/limit_incomplete.sh
 create mode 100644 tests/bfs/limit_one.sh

(limited to 'src/opt.c')

diff --git a/completions/bfs.bash b/completions/bfs.bash
index 2f52e8d..db582da 100644
--- a/completions/bfs.bash
+++ b/completions/bfs.bash
@@ -37,6 +37,7 @@ _bfs() {
         -ipath
         -iregex
         -iwholename
+        -limit
         -links
         -lname
         -maxdepth
@@ -94,8 +95,6 @@ _bfs() {
         -depth
         -follow
         -ignore_readdir_race
-        -maxdepth
-        -mindepth
         -mount
         -nocolor
         -noignore_readdir_race
diff --git a/completions/bfs.fish b/completions/bfs.fish
index 3f399e7..1303639 100644
--- a/completions/bfs.fish
+++ b/completions/bfs.fish
@@ -133,6 +133,7 @@ complete -c bfs -o fls -d "Like -ls, but write to specified file" -F
 complete -c bfs -o fprint -d "Like -print, but write to specified file" -F
 complete -c bfs -o fprint0 -d "Like -print0, but write to specified file" -F
 complete -c bfs -o fprintf -d "Like -printf, but write to specified file" -F
+complete -c bfs -o limit -d "Limit the number of results" -x
 complete -c bfs -o ls -d "List files like ls -dils"
 complete -c bfs -o print -d "Print the path to the found file"
 complete -c bfs -o print0 -d "Like -print, but use the null character as a separator rather than newlines"
diff --git a/completions/bfs.zsh b/completions/bfs.zsh
index 3d7dc3a..51b5029 100644
--- a/completions/bfs.zsh
+++ b/completions/bfs.zsh
@@ -133,6 +133,7 @@ args=(
     '*-fprint0[print the path to the found file using null character as separator, but write to FILE instead of standard output]:output file:_files'
     '*-fprintf[print according to format string, but write to FILE instead of standard output]:output file:_files:output format'
 
+    '*-limit[quit after N results]:maximum result count'
     '*-ls[list files like ls -dils]'
     '*-print[print the path to the found file]'
     '*-print0[print the path to the found file using null character as separator]'
diff --git a/docs/USAGE.md b/docs/USAGE.md
index 3efdee0..071c95b 100644
--- a/docs/USAGE.md
+++ b/docs/USAGE.md
@@ -130,6 +130,40 @@ Unlike `-prune`, `-exclude` even works in combination with `-depth`/`-delete`.
 
 ---
 
+### `-limit`
+
+The `-limit N` action makes `bfs` quit once it gets evaluated `N` times.
+Placing it after an action like `-print` limits the number of results that get printed, for example:
+
+```console
+$ bfs -s -type f -name '*.txt'
+./1.txt
+./2.txt
+./3.txt
+./4.txt
+$ bfs -s -type f -name '*.txt' -print -limit 2
+./1.txt
+./2.txt
+```
+
+This is similar to
+
+```console
+$ bfs -s -type f -name '*.txt' | head -n2
+```
+
+but more powerful because you can apply separate limits to different expressions:
+
+```console
+$ bfs \( -name '*.txt' -print -limit 3 -o -name '*.log' -print -limit 4 \) -limit 5
+[At most 3 .txt files, at most 4 .log files, and at most 5 in total]
+```
+
+and more efficient because it will quit immediately.
+When piping to `head`, `bfs` will only quit *after* it tries to output too many results.
+
+---
+
 ### `-hidden`/`-nohidden`
 
 `-hidden` matches "hidden" files (dotfiles).
diff --git a/docs/bfs.1 b/docs/bfs.1
index 2ecb891..3a4f15a 100644
--- a/docs/bfs.1
+++ b/docs/bfs.1
@@ -725,6 +725,11 @@ but write to
 instead of standard output.
 .RE
 .TP
+\fB\-limit \fIN\fR
+Quit once this action is evaluated
+.I N
+times.
+.TP
 .B \-ls
 List files like
 .B ls
diff --git a/src/eval.c b/src/eval.c
index 9e55964..2f06858 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -840,6 +840,19 @@ error:
 	return true;
 }
 
+/**
+ * -limit action.
+ */
+bool eval_limit(const struct bfs_expr *expr, struct bfs_eval *state) {
+	long long evals = expr->evaluations + 1;
+	if (evals >= expr->num) {
+		state->action = BFTW_STOP;
+		state->quit = true;
+	}
+
+	return true;
+}
+
 /**
  * -prune action.
  */
diff --git a/src/eval.h b/src/eval.h
index 98bbc08..f7f6c77 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -88,6 +88,7 @@ bool eval_fprint(const struct bfs_expr *expr, struct bfs_eval *state);
 bool eval_fprint0(const struct bfs_expr *expr, struct bfs_eval *state);
 bool eval_fprintf(const struct bfs_expr *expr, struct bfs_eval *state);
 bool eval_fprintx(const struct bfs_expr *expr, struct bfs_eval *state);
+bool eval_limit(const struct bfs_expr *expr, struct bfs_eval *state);
 bool eval_prune(const struct bfs_expr *expr, struct bfs_eval *state);
 bool eval_quit(const struct bfs_expr *expr, struct bfs_eval *state);
 
diff --git a/src/opt.c b/src/opt.c
index 76965de..a470d25 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1181,6 +1181,7 @@ static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *exp
 		eval_fprint0,
 		eval_fprintf,
 		eval_fprintx,
+		eval_limit,
 		eval_prune,
 		eval_true,
 		// Non-returning
diff --git a/src/parse.c b/src/parse.c
index 3b7386d..2dfcab2 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -97,6 +97,8 @@ struct bfs_parser {
 	char **last_arg;
 	/** A "-depth"-type argument, if any. */
 	char **depth_arg;
+	/** A "-limit" argument, if any. */
+	char **limit_arg;
 	/** A "-prune" argument, if any. */
 	char **prune_arg;
 	/** A "-mount" argument, if any. */
@@ -733,7 +735,7 @@ static struct bfs_expr *parse_action(struct bfs_parser *parser, bfs_eval_fn *eva
 		return NULL;
 	}
 
-	if (eval_fn != eval_prune && eval_fn != eval_quit) {
+	if (eval_fn != eval_limit && eval_fn != eval_prune && eval_fn != eval_quit) {
 		parser->implicit_print = false;
 	}
 
@@ -1569,6 +1571,29 @@ static struct bfs_expr *parse_jobs(struct bfs_parser *parser, int arg1, int arg2
 	return expr;
 }
 
+/**
+ * Parse -limit N.
+ */
+static struct bfs_expr *parse_limit(struct bfs_parser *parser, int arg1, int arg2) {
+	struct bfs_expr *expr = parse_unary_action(parser, eval_limit);
+	if (!expr) {
+		return NULL;
+	}
+
+	char **arg = &expr->argv[1];
+	if (!parse_int(parser, arg, *arg, &expr->num, IF_LONG_LONG)) {
+		return NULL;
+	}
+
+	if (expr->num <= 0) {
+		parse_expr_error(parser, expr, "The ${blu}%s${rs} must be at least ${bld}1${rs}.\n", expr->argv[0]);
+		return NULL;
+	}
+
+	parser->limit_arg = expr->argv;
+	return expr;
+}
+
 /**
  * Parse -links N.
  */
@@ -2845,6 +2870,8 @@ static struct bfs_expr *parse_help(struct bfs_parser *parser, int arg1, int arg2
 	cfprintf(cout, "  ${blu}-fprintf${rs} ${bld}FILE${rs} ${bld}FORMAT${rs}\n");
 	cfprintf(cout, "      Like ${blu}-ls${rs}/${blu}-print${rs}/${blu}-print0${rs}/${blu}-printf${rs}, but write to ${bld}FILE${rs} instead of standard\n"
 	               "      output\n");
+	cfprintf(cout, "  ${blu}-limit${rs} ${bld}N${rs}\n");
+	cfprintf(cout, "      Quit after this action is evaluated ${bld}N${rs} times\n");
 	cfprintf(cout, "  ${blu}-ls${rs}\n");
 	cfprintf(cout, "      List files like ${ex}ls${rs} ${bld}-dils${rs}\n");
 	cfprintf(cout, "  ${blu}-print${rs}\n");
@@ -2968,6 +2995,7 @@ static const struct table_entry parse_table[] = {
 	{"-iregex", T_TEST, parse_regex, BFS_REGEX_ICASE},
 	{"-iwholename", T_TEST, parse_path, true},
 	{"-j", T_FLAG, parse_jobs, 0, 0, true},
+	{"-limit", T_ACTION, parse_limit},
 	{"-links", T_TEST, parse_links},
 	{"-lname", T_TEST, parse_lname, false},
 	{"-ls", T_ACTION, parse_ls},
@@ -3330,6 +3358,14 @@ static struct bfs_expr *parse_whole_expr(struct bfs_parser *parser) {
 	}
 
 	if (parser->implicit_print) {
+		char **limit = parser->limit_arg;
+		if (limit) {
+			parse_argv_error(parser, parser->limit_arg, 2,
+				"With ${blu}%s${rs}, you must specify an action explicitly; for example, ${blu}-print${rs} ${blu}%s${rs} ${bld}%s${rs}.\n",
+				limit[0], limit[0], limit[1]);
+			return NULL;
+		}
+
 		struct bfs_expr *print = parse_new_expr(parser, eval_fprint, 1, &fake_print_arg);
 		if (!print) {
 			return NULL;
diff --git a/tests/bfs/limit.out b/tests/bfs/limit.out
new file mode 100644
index 0000000..ea94276
--- /dev/null
+++ b/tests/bfs/limit.out
@@ -0,0 +1,4 @@
+basic/a
+basic/b
+basic/c/d
+basic/e/f
diff --git a/tests/bfs/limit.sh b/tests/bfs/limit.sh
new file mode 100644
index 0000000..84b605f
--- /dev/null
+++ b/tests/bfs/limit.sh
@@ -0,0 +1 @@
+bfs_diff -s basic -type f -print -limit 4
diff --git a/tests/bfs/limit_0.sh b/tests/bfs/limit_0.sh
new file mode 100644
index 0000000..3ce26de
--- /dev/null
+++ b/tests/bfs/limit_0.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit 0
diff --git a/tests/bfs/limit_implicit_print.sh b/tests/bfs/limit_implicit_print.sh
new file mode 100644
index 0000000..cdb059d
--- /dev/null
+++ b/tests/bfs/limit_implicit_print.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -type f -limit 1
diff --git a/tests/bfs/limit_incomplete.sh b/tests/bfs/limit_incomplete.sh
new file mode 100644
index 0000000..2d1e842
--- /dev/null
+++ b/tests/bfs/limit_incomplete.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit
diff --git a/tests/bfs/limit_one.sh b/tests/bfs/limit_one.sh
new file mode 100644
index 0000000..3f8181c
--- /dev/null
+++ b/tests/bfs/limit_one.sh
@@ -0,0 +1 @@
+! invoke_bfs basic -print -limit one
-- 
cgit v1.2.3


From c643e1dd27e633c67589b622a06582bbb6fb5cf6 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Fri, 22 Mar 2024 14:06:04 -0400
Subject: Fix some -Wpedantic warnings

---
 src/config.h |  6 ++----
 src/opt.c    | 12 ++++++------
 2 files changed, 8 insertions(+), 10 deletions(-)

(limited to 'src/opt.c')

diff --git a/src/config.h b/src/config.h
index 45422a2..892f24c 100644
--- a/src/config.h
+++ b/src/config.h
@@ -192,9 +192,7 @@ typedef long double max_align_t;
 /**
  * Silence warnings about switch/case fall-throughs.
  */
-#if __has_c_attribute(fallthrough)
-#  define fallthru [[fallthrough]]
-#elif __has_attribute(fallthrough)
+#if __has_attribute(fallthrough)
 #  define fallthru __attribute__((fallthrough))
 #else
 #  define fallthru ((void)0)
@@ -309,7 +307,7 @@ typedef long double max_align_t;
  *     attr_d
  */
 #define attr(...) \
-	attr__(attr_##__VA_ARGS__, none, none, none, none, none, none, none, none, none)
+	attr__(attr_##__VA_ARGS__, none, none, none, none, none, none, none, none, none, )
 
 /**
  * attr() helper.  For exposition, pretend we support only 2 args, instead of 9.
diff --git a/src/opt.c b/src/opt.c
index a470d25..b74b4e1 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -724,7 +724,7 @@ struct visitor {
 	visit_fn *leave;
 
 	/** A visitor lookup table. */
-	struct visitor_table table[];
+	const struct visitor_table *table;
 };
 
 /** Recursive visitor implementation. */
@@ -1331,7 +1331,7 @@ static struct bfs_expr *annotate_visit(struct bfs_opt *opt, struct bfs_expr *exp
 static const struct visitor annotate = {
 	.name = "annotate",
 	.visit = annotate_visit,
-	.table = {
+	.table = (const struct visitor_table[]) {
 		{eval_access, annotate_access},
 		{eval_empty, annotate_empty},
 		{eval_exec, annotate_exec},
@@ -1516,7 +1516,7 @@ static struct bfs_expr *canonicalize_assoc(struct bfs_opt *opt, struct bfs_expr
  */
 static const struct visitor canonicalize = {
 	.name = "canonicalize",
-	.table = {
+	.table = (const struct visitor_table[]) {
 		{eval_not, canonicalize_not},
 		{eval_and, canonicalize_assoc},
 		{eval_or, canonicalize_assoc},
@@ -1609,7 +1609,7 @@ static struct bfs_expr *reorder_andor(struct bfs_opt *opt, struct bfs_expr *expr
  */
 static const struct visitor reorder = {
 	.name = "reorder",
-	.table = {
+	.table = (const struct visitor_table[]) {
 		{eval_and, reorder_andor},
 		{eval_or, reorder_andor},
 		{NULL, NULL},
@@ -1887,7 +1887,7 @@ static const struct visitor data_flow = {
 	.enter = data_flow_enter,
 	.visit = data_flow_visit,
 	.leave = data_flow_leave,
-	.table = {
+	.table = (const struct visitor_table[]) {
 		{eval_access, data_flow_access},
 		{eval_gid, data_flow_gid},
 		{eval_inum, data_flow_inum},
@@ -2103,7 +2103,7 @@ static struct bfs_expr *simplify_comma(struct bfs_opt *opt, struct bfs_expr *exp
  */
 static const struct visitor simplify = {
 	.name = "simplify",
-	.table = {
+	.table = (const struct visitor_table[]) {
 		{eval_not, simplify_not},
 		{eval_and, simplify_and},
 		{eval_or, simplify_or},
-- 
cgit v1.2.3


From c66379749f423413913b406609dfe9311ba6e555 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Thu, 18 Apr 2024 14:53:56 -0400
Subject: Rename config.h to prelude.h

---
 src/alloc.c    |   2 +-
 src/alloc.h    |   2 +-
 src/bar.c      |   2 +-
 src/bfstd.c    |   2 +-
 src/bfstd.h    |   2 +-
 src/bftw.c     |   2 +-
 src/bit.h      |   2 +-
 src/color.c    |   2 +-
 src/color.h    |   2 +-
 src/config.h   | 377 ---------------------------------------------------------
 src/ctx.h      |   2 +-
 src/diag.c     |   2 +-
 src/diag.h     |   2 +-
 src/dir.c      |   2 +-
 src/dstring.c  |   2 +-
 src/dstring.h  |   2 +-
 src/eval.c     |   2 +-
 src/eval.h     |   2 +-
 src/exec.c     |   2 +-
 src/expr.h     |   2 +-
 src/fsade.c    |   2 +-
 src/fsade.h    |   2 +-
 src/ioq.c      |   2 +-
 src/ioq.h      |   2 +-
 src/main.c     |   4 +-
 src/mtab.c     |   2 +-
 src/mtab.h     |   2 +-
 src/opt.c      |   2 +-
 src/parse.c    |   2 +-
 src/prelude.h  | 377 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/printf.c   |   2 +-
 src/pwcache.c  |   2 +-
 src/sanity.h   |   2 +-
 src/stat.c     |   2 +-
 src/stat.h     |   2 +-
 src/thread.c   |   2 +-
 src/thread.h   |   2 +-
 src/trie.c     |   2 +-
 src/xregex.c   |   2 +-
 src/xspawn.c   |   2 +-
 src/xspawn.h   |   2 +-
 src/xtime.c    |   2 +-
 tests/alloc.c  |   2 +-
 tests/bfstd.c  |   2 +-
 tests/bit.c    |   2 +-
 tests/ioq.c    |   2 +-
 tests/main.c   |   2 +-
 tests/tests.h  |   2 +-
 tests/trie.c   |   2 +-
 tests/xspawn.c |   2 +-
 tests/xtime.c  |   2 +-
 tests/xtouch.c |   2 +-
 52 files changed, 428 insertions(+), 428 deletions(-)
 delete mode 100644 src/config.h
 create mode 100644 src/prelude.h

(limited to 'src/opt.c')

diff --git a/src/alloc.c b/src/alloc.c
index b65d0c5..ec8608f 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "alloc.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include <errno.h>
diff --git a/src/alloc.h b/src/alloc.h
index ae055bc..095134a 100644
--- a/src/alloc.h
+++ b/src/alloc.h
@@ -8,7 +8,7 @@
 #ifndef BFS_ALLOC_H
 #define BFS_ALLOC_H
 
-#include "config.h"
+#include "prelude.h"
 #include <errno.h>
 #include <stddef.h>
 #include <stdlib.h>
diff --git a/src/bar.c b/src/bar.c
index 8ab4112..184d9a0 100644
--- a/src/bar.c
+++ b/src/bar.c
@@ -1,11 +1,11 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "bar.h"
 #include "atomic.h"
 #include "bfstd.h"
 #include "bit.h"
-#include "config.h"
 #include "dstring.h"
 #include <errno.h>
 #include <fcntl.h>
diff --git a/src/bfstd.c b/src/bfstd.c
index 2499f00..e1b4804 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "bfstd.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include "thread.h"
diff --git a/src/bfstd.h b/src/bfstd.h
index fc22971..42f5d5b 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -8,7 +8,7 @@
 #ifndef BFS_BFSTD_H
 #define BFS_BFSTD_H
 
-#include "config.h"
+#include "prelude.h"
 #include "sanity.h"
 #include <stddef.h>
 
diff --git a/src/bftw.c b/src/bftw.c
index 6130c44..c4d3c17 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -18,10 +18,10 @@
  *   various helper functions to take fewer parameters.
  */
 
+#include "prelude.h"
 #include "bftw.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include "dir.h"
 #include "dstring.h"
diff --git a/src/bit.h b/src/bit.h
index 69df21e..17cfbcf 100644
--- a/src/bit.h
+++ b/src/bit.h
@@ -8,7 +8,7 @@
 #ifndef BFS_BIT_H
 #define BFS_BIT_H
 
-#include "config.h"
+#include "prelude.h"
 #include <limits.h>
 #include <stdint.h>
 
diff --git a/src/color.c b/src/color.c
index 8c32a68..f004bf2 100644
--- a/src/color.c
+++ b/src/color.c
@@ -1,11 +1,11 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "color.h"
 #include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
-#include "config.h"
 #include "diag.h"
 #include "dir.h"
 #include "dstring.h"
diff --git a/src/color.h b/src/color.h
index e3e7973..3278cd6 100644
--- a/src/color.h
+++ b/src/color.h
@@ -8,7 +8,7 @@
 #ifndef BFS_COLOR_H
 #define BFS_COLOR_H
 
-#include "config.h"
+#include "prelude.h"
 #include "dstring.h"
 #include <stdio.h>
 
diff --git a/src/config.h b/src/config.h
deleted file mode 100644
index 2eff1fc..0000000
--- a/src/config.h
+++ /dev/null
@@ -1,377 +0,0 @@
-// Copyright © Tavian Barnes <tavianator@tavianator.com>
-// SPDX-License-Identifier: 0BSD
-
-/**
- * Configuration and feature/platform detection.
- */
-
-#ifndef BFS_CONFIG_H
-#define BFS_CONFIG_H
-
-// Possible __STDC_VERSION__ values
-
-#define C95 199409L
-#define C99 199901L
-#define C11 201112L
-#define C17 201710L
-#define C23 202311L
-
-#include <stddef.h>
-
-#if __STDC_VERSION__ < C23
-#  include <stdalign.h>
-#  include <stdbool.h>
-#  include <stdnoreturn.h>
-#endif
-
-// bfs packaging configuration
-
-#ifndef BFS_COMMAND
-#  define BFS_COMMAND "bfs"
-#endif
-#ifndef BFS_HOMEPAGE
-#  define BFS_HOMEPAGE "https://tavianator.com/projects/bfs.html"
-#endif
-
-// This is a symbol instead of a literal so we don't have to rebuild everything
-// when the version number changes
-extern const char bfs_version[];
-
-// Check for system headers
-
-#ifdef __has_include
-
-#if __has_include(<mntent.h>)
-#  define BFS_HAS_MNTENT_H true
-#endif
-#if __has_include(<paths.h>)
-#  define BFS_HAS_PATHS_H true
-#endif
-#if __has_include(<sys/acl.h>)
-#  define BFS_HAS_SYS_ACL_H true
-#endif
-#if __has_include(<sys/capability.h>)
-#  define BFS_HAS_SYS_CAPABILITY_H true
-#endif
-#if __has_include(<sys/extattr.h>)
-#  define BFS_HAS_SYS_EXTATTR_H true
-#endif
-#if __has_include(<sys/mkdev.h>)
-#  define BFS_HAS_SYS_MKDEV_H true
-#endif
-#if __has_include(<sys/param.h>)
-#  define BFS_HAS_SYS_PARAM_H true
-#endif
-#if __has_include(<sys/sysmacros.h>)
-#  define BFS_HAS_SYS_SYSMACROS_H true
-#endif
-#if __has_include(<sys/xattr.h>)
-#  define BFS_HAS_SYS_XATTR_H true
-#endif
-#if __has_include(<threads.h>)
-#  define BFS_HAS_THREADS_H true
-#endif
-#if __has_include(<util.h>)
-#  define BFS_HAS_UTIL_H true
-#endif
-
-#else // !__has_include
-
-#define BFS_HAS_MNTENT_H __GLIBC__
-#define BFS_HAS_PATHS_H true
-#define BFS_HAS_SYS_ACL_H true
-#define BFS_HAS_SYS_CAPABILITY_H __linux__
-#define BFS_HAS_SYS_EXTATTR_H __FreeBSD__
-#define BFS_HAS_SYS_MKDEV_H false
-#define BFS_HAS_SYS_PARAM_H true
-#define BFS_HAS_SYS_SYSMACROS_H __GLIBC__
-#define BFS_HAS_SYS_XATTR_H __linux__
-#define BFS_HAS_THREADS_H (!__STDC_NO_THREADS__)
-#define BFS_HAS_UTIL_H __NetBSD__
-
-#endif // !__has_include
-
-#ifndef BFS_USE_MNTENT_H
-#  define BFS_USE_MNTENT_H BFS_HAS_MNTENT_H
-#endif
-#ifndef BFS_USE_PATHS_H
-#  define BFS_USE_PATHS_H BFS_HAS_PATHS_H
-#endif
-#ifndef BFS_USE_SYS_ACL_H
-#  define BFS_USE_SYS_ACL_H (BFS_HAS_SYS_ACL_H && !__illumos__ && (!__linux__ || BFS_USE_LIBACL))
-#endif
-#ifndef BFS_USE_SYS_CAPABILITY_H
-#  define BFS_USE_SYS_CAPABILITY_H (BFS_HAS_SYS_CAPABILITY_H && !__FreeBSD__ && (!__linux__ || BFS_USE_LIBCAP))
-#endif
-#ifndef BFS_USE_SYS_EXTATTR_H
-#  define BFS_USE_SYS_EXTATTR_H (BFS_HAS_SYS_EXTATTR_H && !__DragonFly__)
-#endif
-#ifndef BFS_USE_SYS_MKDEV_H
-#  define BFS_USE_SYS_MKDEV_H BFS_HAS_SYS_MKDEV_H
-#endif
-#ifndef BFS_USE_SYS_PARAM_H
-#  define BFS_USE_SYS_PARAM_H BFS_HAS_SYS_PARAM_H
-#endif
-#ifndef BFS_USE_SYS_SYSMACROS_H
-#  define BFS_USE_SYS_SYSMACROS_H BFS_HAS_SYS_SYSMACROS_H
-#endif
-#ifndef BFS_USE_SYS_XATTR_H
-#  define BFS_USE_SYS_XATTR_H BFS_HAS_SYS_XATTR_H
-#endif
-#ifndef BFS_USE_THREADS_H
-#  define BFS_USE_THREADS_H BFS_HAS_THREADS_H
-#endif
-#ifndef BFS_USE_UTIL_H
-#  define BFS_USE_UTIL_H BFS_HAS_UTIL_H
-#endif
-
-// Stub out feature detection on old/incompatible compilers
-
-#ifndef __has_feature
-#  define __has_feature(feat) false
-#endif
-
-#ifndef __has_c_attribute
-#  define __has_c_attribute(attr) false
-#endif
-
-#ifndef __has_attribute
-#  define __has_attribute(attr) false
-#endif
-
-// Platform detection
-
-// Get the definition of BSD if available
-#if BFS_USE_SYS_PARAM_H
-#  include <sys/param.h>
-#endif
-
-#ifndef __GLIBC_PREREQ
-#  define __GLIBC_PREREQ(maj, min) false
-#endif
-
-#ifndef __NetBSD_Prereq__
-#  define __NetBSD_Prereq__(maj, min, patch) false
-#endif
-
-// Fundamental utilities
-
-/**
- * Get the length of an array.
- */
-#define countof(array) (sizeof(array) / sizeof(0[array]))
-
-/**
- * False sharing/destructive interference/largest cache line size.
- */
-#ifdef __GCC_DESTRUCTIVE_SIZE
-#  define FALSE_SHARING_SIZE __GCC_DESTRUCTIVE_SIZE
-#else
-#  define FALSE_SHARING_SIZE 64
-#endif
-
-/**
- * True sharing/constructive interference/smallest cache line size.
- */
-#ifdef __GCC_CONSTRUCTIVE_SIZE
-#  define TRUE_SHARING_SIZE __GCC_CONSTRUCTIVE_SIZE
-#else
-#  define TRUE_SHARING_SIZE 64
-#endif
-
-/**
- * Alignment specifier that avoids false sharing.
- */
-#define cache_align alignas(FALSE_SHARING_SIZE)
-
-#if __COSMOPOLITAN__
-typedef long double max_align_t;
-#endif
-
-// Wrappers for attributes
-
-/**
- * Silence warnings about switch/case fall-throughs.
- */
-#if __has_attribute(fallthrough)
-#  define fallthru __attribute__((fallthrough))
-#else
-#  define fallthru ((void)0)
-#endif
-
-/**
- * Silence warnings about unused declarations.
- */
-#if __has_attribute(unused)
-#  define attr_maybe_unused __attribute__((unused))
-#else
-#  define attr_maybe_unused
-#endif
-
-/**
- * Warn if a value is unused.
- */
-#if __has_attribute(warn_unused_result)
-#  define attr_nodiscard __attribute__((warn_unused_result))
-#else
-#  define attr_nodiscard
-#endif
-
-/**
- * Hint to avoid inlining a function.
- */
-#if __has_attribute(noinline)
-#  define attr_noinline __attribute__((noinline))
-#else
-#  define attr_noinline
-#endif
-
-/**
- * Hint that a function is unlikely to be called.
- */
-#if __has_attribute(cold)
-#  define attr_cold attr_noinline __attribute__((cold))
-#else
-#  define attr_cold attr_noinline
-#endif
-
-/**
- * Adds compiler warnings for bad printf()-style function calls, if supported.
- */
-#if __has_attribute(format)
-#  define attr_printf(fmt, args) __attribute__((format(printf, fmt, args)))
-#else
-#  define attr_printf(fmt, args)
-#endif
-
-/**
- * Annotates allocator-like functions.
- */
-#if __has_attribute(malloc)
-#  if __GNUC__ >= 11 && !__OPTIMIZE__ // malloc(deallocator) disables inlining on GCC
-#    define attr_malloc(...) attr_nodiscard __attribute__((malloc(__VA_ARGS__)))
-#  else
-#    define attr_malloc(...) attr_nodiscard __attribute__((malloc))
-#  endif
-#else
-#  define attr_malloc(...) attr_nodiscard
-#endif
-
-/**
- * Specifies that a function returns allocations with a given alignment.
- */
-#if __has_attribute(alloc_align)
-#  define attr_alloc_align(param) __attribute__((alloc_align(param)))
-#else
-#  define attr_alloc_align(param)
-#endif
-
-/**
- * Specifies that a function returns allocations with a given size.
- */
-#if __has_attribute(alloc_size)
-#  define attr_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
-#else
-#  define attr_alloc_size(...)
-#endif
-
-/**
- * Shorthand for attr_alloc_align() and attr_alloc_size().
- */
-#define attr_aligned_alloc(align, ...) \
-	attr_alloc_align(align) \
-	attr_alloc_size(__VA_ARGS__)
-
-/**
- * Check if function multiversioning via GNU indirect functions (ifunc) is supported.
- */
-#ifndef BFS_USE_TARGET_CLONES
-#  if __has_attribute(target_clones) && (__GLIBC__ || __FreeBSD__)
-#    define BFS_USE_TARGET_CLONES true
-#  endif
-#endif
-
-/**
- * Apply the target_clones attribute, if available.
- */
-#if BFS_USE_TARGET_CLONES
-#  define attr_target_clones(...) __attribute__((target_clones(__VA_ARGS__)))
-#else
-#  define attr_target_clones(...)
-#endif
-
-/**
- * Shorthand for multiple attributes at once. attr(a, b(c), d) is equivalent to
- *
- *     attr_a
- *     attr_b(c)
- *     attr_d
- */
-#define attr(...) \
-	attr__(attr_##__VA_ARGS__, none, none, none, none, none, none, none, none, none, )
-
-/**
- * attr() helper.  For exposition, pretend we support only 2 args, instead of 9.
- * There are a few cases:
- *
- *     attr()
- *         => attr__(attr_, none, none)
- *         => attr_                =>
- *            attr_none            =>
- *            attr_too_many_none() =>
- *
- *     attr(a)
- *         => attr__(attr_a, none, none)
- *         => attr_a               => __attribute__((a))
- *            attr_none            =>
- *            attr_too_many_none() =>
- *
- *     attr(a, b(c))
- *         => attr__(attr_a, b(c), none, none)
- *         => attr_a                   => __attribute__((a))
- *            attr_b(c)                => __attribute__((b(c)))
- *            attr_too_many_none(none) =>
- *
- *     attr(a, b(c), d)
- *         => attr__(attr_a, b(c), d, none, none)
- *         => attr_a                      => __attribute__((a))
- *            attr_b(c)                   => __attribute__((b(c)))
- *            attr_too_many_d(none, none) => error
- *
- * Some attribute names are the same as standard library functions, e.g. printf.
- * Standard libraries are permitted to define these functions as macros, like
- *
- *     #define printf(...) __builtin_printf(__VA_ARGS__)
- *
- * The token paste in
- *
- *     #define attr(...) attr__(attr_##__VA_ARGS__, none, none)
- *
- * is necessary to prevent macro expansion before evaluating attr__().
- * Otherwise, we could get
- *
- *     attr(printf(1, 2))
- *         => attr__(__builtin_printf(1, 2), none, none)
- *         => attr____builtin_printf(1, 2)
- *         => error
- */
-#define attr__(a1, a2, a3, a4, a5, a6, a7, a8, a9, none, ...) \
-	a1 \
-	attr_##a2 \
-	attr_##a3 \
-	attr_##a4 \
-	attr_##a5 \
-	attr_##a6 \
-	attr_##a7 \
-	attr_##a8 \
-	attr_##a9 \
-	attr_too_many_##none(__VA_ARGS__)
-
-// Ignore `attr_none` from expanding 1-9 argument attr(a1, a2, ...)
-#define attr_none
-// Ignore `attr_` from expanding 0-argument attr()
-#define attr_
-// Only trigger an error on more than 9 arguments
-#define attr_too_many_none(...)
-
-#endif // BFS_CONFIG_H
diff --git a/src/ctx.h b/src/ctx.h
index e14db21..fc3020c 100644
--- a/src/ctx.h
+++ b/src/ctx.h
@@ -8,9 +8,9 @@
 #ifndef BFS_CTX_H
 #define BFS_CTX_H
 
+#include "prelude.h"
 #include "alloc.h"
 #include "bftw.h"
-#include "config.h"
 #include "diag.h"
 #include "expr.h"
 #include "trie.h"
diff --git a/src/diag.c b/src/diag.c
index cb27b92..deb6f26 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -1,11 +1,11 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "diag.h"
 #include "alloc.h"
 #include "bfstd.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "dstring.h"
 #include "expr.h"
diff --git a/src/diag.h b/src/diag.h
index 4054c48..2b13609 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -8,7 +8,7 @@
 #ifndef BFS_DIAG_H
 #define BFS_DIAG_H
 
-#include "config.h"
+#include "prelude.h"
 #include <stdarg.h>
 
 /**
diff --git a/src/dir.c b/src/dir.c
index 98518f2..53c9be3 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "dir.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include "trie.h"
diff --git a/src/dstring.c b/src/dstring.c
index 10b0fad..913dda8 100644
--- a/src/dstring.c
+++ b/src/dstring.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "dstring.h"
 #include "alloc.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include <stdarg.h>
 #include <stddef.h>
diff --git a/src/dstring.h b/src/dstring.h
index 6006199..9ea7eb9 100644
--- a/src/dstring.h
+++ b/src/dstring.h
@@ -8,8 +8,8 @@
 #ifndef BFS_DSTRING_H
 #define BFS_DSTRING_H
 
+#include "prelude.h"
 #include "bfstd.h"
-#include "config.h"
 #include <stdarg.h>
 #include <stddef.h>
 
diff --git a/src/eval.c b/src/eval.c
index d0112c2..b103912 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5,12 +5,12 @@
  * Implementation of all the primary expressions.
  */
 
+#include "prelude.h"
 #include "eval.h"
 #include "bar.h"
 #include "bfstd.h"
 #include "bftw.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "dir.h"
diff --git a/src/eval.h b/src/eval.h
index ae43628..4dd7996 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -9,7 +9,7 @@
 #ifndef BFS_EVAL_H
 #define BFS_EVAL_H
 
-#include "config.h"
+#include "prelude.h"
 
 struct bfs_ctx;
 struct bfs_expr;
diff --git a/src/exec.c b/src/exec.c
index 60bfd28..e782d49 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -1,12 +1,12 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "exec.h"
 #include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "dstring.h"
diff --git a/src/expr.h b/src/expr.h
index 75cb5fd..7bcace7 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -8,8 +8,8 @@
 #ifndef BFS_EXPR_H
 #define BFS_EXPR_H
 
+#include "prelude.h"
 #include "color.h"
-#include "config.h"
 #include "eval.h"
 #include "stat.h"
 #include <sys/types.h>
diff --git a/src/fsade.c b/src/fsade.c
index 0810c7f..34a4d57 100644
--- a/src/fsade.c
+++ b/src/fsade.c
@@ -1,11 +1,11 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "fsade.h"
 #include "atomic.h"
 #include "bfstd.h"
 #include "bftw.h"
-#include "config.h"
 #include "dir.h"
 #include "dstring.h"
 #include "sanity.h"
diff --git a/src/fsade.h b/src/fsade.h
index 1f1dbfc..6300852 100644
--- a/src/fsade.h
+++ b/src/fsade.h
@@ -9,7 +9,7 @@
 #ifndef BFS_FSADE_H
 #define BFS_FSADE_H
 
-#include "config.h"
+#include "prelude.h"
 
 #define BFS_CAN_CHECK_ACL BFS_USE_SYS_ACL_H
 
diff --git a/src/ioq.c b/src/ioq.c
index b936681..189bdac 100644
--- a/src/ioq.c
+++ b/src/ioq.c
@@ -118,12 +118,12 @@
  * [1]: https://arxiv.org/abs/2201.02179
  */
 
+#include "prelude.h"
 #include "ioq.h"
 #include "alloc.h"
 #include "atomic.h"
 #include "bfstd.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include "dir.h"
 #include "stat.h"
diff --git a/src/ioq.h b/src/ioq.h
index 818eea6..d8e1573 100644
--- a/src/ioq.h
+++ b/src/ioq.h
@@ -8,7 +8,7 @@
 #ifndef BFS_IOQ_H
 #define BFS_IOQ_H
 
-#include "config.h"
+#include "prelude.h"
 #include "dir.h"
 #include "stat.h"
 #include <stddef.h>
diff --git a/src/main.c b/src/main.c
index e120f03..9d8b206 100644
--- a/src/main.c
+++ b/src/main.c
@@ -26,7 +26,7 @@
  *     - bit.h         (bit manipulation)
  *     - bfstd.[ch]    (standard library wrappers/polyfills)
  *     - color.[ch]    (for pretty terminal colors)
- *     - config.h      (configuration and feature/platform detection)
+ *     - prelude.h     (configuration and feature/platform detection)
  *     - diag.[ch]     (formats diagnostic messages)
  *     - dir.[ch]      (a directory API facade)
  *     - dstring.[ch]  (a dynamic string library)
@@ -45,8 +45,8 @@
  *     - xtime.[ch]    (date/time handling utilities)
  */
 
+#include "prelude.h"
 #include "bfstd.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "eval.h"
diff --git a/src/mtab.c b/src/mtab.c
index 86ae151..7905d14 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "mtab.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "stat.h"
 #include "trie.h"
 #include <errno.h>
diff --git a/src/mtab.h b/src/mtab.h
index d99d78f..67290c2 100644
--- a/src/mtab.h
+++ b/src/mtab.h
@@ -8,7 +8,7 @@
 #ifndef BFS_MTAB_H
 #define BFS_MTAB_H
 
-#include "config.h"
+#include "prelude.h"
 
 struct bfs_stat;
 
diff --git a/src/opt.c b/src/opt.c
index b74b4e1..ffc795b 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -25,11 +25,11 @@
  * effects are reachable at all, skipping the traversal if not.
  */
 
+#include "prelude.h"
 #include "opt.h"
 #include "bftw.h"
 #include "bit.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "dir.h"
diff --git a/src/parse.c b/src/parse.c
index a3e32fe..c2ae58f 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -8,12 +8,12 @@
  * flags like always-true options, and skipping over paths wherever they appear.
  */
 
+#include "prelude.h"
 #include "parse.h"
 #include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "dir.h"
diff --git a/src/prelude.h b/src/prelude.h
new file mode 100644
index 0000000..c3a0752
--- /dev/null
+++ b/src/prelude.h
@@ -0,0 +1,377 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+/**
+ * Configuration and feature/platform detection.
+ */
+
+#ifndef BFS_PRELUDE_H
+#define BFS_PRELUDE_H
+
+// Possible __STDC_VERSION__ values
+
+#define C95 199409L
+#define C99 199901L
+#define C11 201112L
+#define C17 201710L
+#define C23 202311L
+
+#include <stddef.h>
+
+#if __STDC_VERSION__ < C23
+#  include <stdalign.h>
+#  include <stdbool.h>
+#  include <stdnoreturn.h>
+#endif
+
+// bfs packaging configuration
+
+#ifndef BFS_COMMAND
+#  define BFS_COMMAND "bfs"
+#endif
+#ifndef BFS_HOMEPAGE
+#  define BFS_HOMEPAGE "https://tavianator.com/projects/bfs.html"
+#endif
+
+// This is a symbol instead of a literal so we don't have to rebuild everything
+// when the version number changes
+extern const char bfs_version[];
+
+// Check for system headers
+
+#ifdef __has_include
+
+#if __has_include(<mntent.h>)
+#  define BFS_HAS_MNTENT_H true
+#endif
+#if __has_include(<paths.h>)
+#  define BFS_HAS_PATHS_H true
+#endif
+#if __has_include(<sys/acl.h>)
+#  define BFS_HAS_SYS_ACL_H true
+#endif
+#if __has_include(<sys/capability.h>)
+#  define BFS_HAS_SYS_CAPABILITY_H true
+#endif
+#if __has_include(<sys/extattr.h>)
+#  define BFS_HAS_SYS_EXTATTR_H true
+#endif
+#if __has_include(<sys/mkdev.h>)
+#  define BFS_HAS_SYS_MKDEV_H true
+#endif
+#if __has_include(<sys/param.h>)
+#  define BFS_HAS_SYS_PARAM_H true
+#endif
+#if __has_include(<sys/sysmacros.h>)
+#  define BFS_HAS_SYS_SYSMACROS_H true
+#endif
+#if __has_include(<sys/xattr.h>)
+#  define BFS_HAS_SYS_XATTR_H true
+#endif
+#if __has_include(<threads.h>)
+#  define BFS_HAS_THREADS_H true
+#endif
+#if __has_include(<util.h>)
+#  define BFS_HAS_UTIL_H true
+#endif
+
+#else // !__has_include
+
+#define BFS_HAS_MNTENT_H __GLIBC__
+#define BFS_HAS_PATHS_H true
+#define BFS_HAS_SYS_ACL_H true
+#define BFS_HAS_SYS_CAPABILITY_H __linux__
+#define BFS_HAS_SYS_EXTATTR_H __FreeBSD__
+#define BFS_HAS_SYS_MKDEV_H false
+#define BFS_HAS_SYS_PARAM_H true
+#define BFS_HAS_SYS_SYSMACROS_H __GLIBC__
+#define BFS_HAS_SYS_XATTR_H __linux__
+#define BFS_HAS_THREADS_H (!__STDC_NO_THREADS__)
+#define BFS_HAS_UTIL_H __NetBSD__
+
+#endif // !__has_include
+
+#ifndef BFS_USE_MNTENT_H
+#  define BFS_USE_MNTENT_H BFS_HAS_MNTENT_H
+#endif
+#ifndef BFS_USE_PATHS_H
+#  define BFS_USE_PATHS_H BFS_HAS_PATHS_H
+#endif
+#ifndef BFS_USE_SYS_ACL_H
+#  define BFS_USE_SYS_ACL_H (BFS_HAS_SYS_ACL_H && !__illumos__ && (!__linux__ || BFS_USE_LIBACL))
+#endif
+#ifndef BFS_USE_SYS_CAPABILITY_H
+#  define BFS_USE_SYS_CAPABILITY_H (BFS_HAS_SYS_CAPABILITY_H && !__FreeBSD__ && (!__linux__ || BFS_USE_LIBCAP))
+#endif
+#ifndef BFS_USE_SYS_EXTATTR_H
+#  define BFS_USE_SYS_EXTATTR_H (BFS_HAS_SYS_EXTATTR_H && !__DragonFly__)
+#endif
+#ifndef BFS_USE_SYS_MKDEV_H
+#  define BFS_USE_SYS_MKDEV_H BFS_HAS_SYS_MKDEV_H
+#endif
+#ifndef BFS_USE_SYS_PARAM_H
+#  define BFS_USE_SYS_PARAM_H BFS_HAS_SYS_PARAM_H
+#endif
+#ifndef BFS_USE_SYS_SYSMACROS_H
+#  define BFS_USE_SYS_SYSMACROS_H BFS_HAS_SYS_SYSMACROS_H
+#endif
+#ifndef BFS_USE_SYS_XATTR_H
+#  define BFS_USE_SYS_XATTR_H BFS_HAS_SYS_XATTR_H
+#endif
+#ifndef BFS_USE_THREADS_H
+#  define BFS_USE_THREADS_H BFS_HAS_THREADS_H
+#endif
+#ifndef BFS_USE_UTIL_H
+#  define BFS_USE_UTIL_H BFS_HAS_UTIL_H
+#endif
+
+// Stub out feature detection on old/incompatible compilers
+
+#ifndef __has_feature
+#  define __has_feature(feat) false
+#endif
+
+#ifndef __has_c_attribute
+#  define __has_c_attribute(attr) false
+#endif
+
+#ifndef __has_attribute
+#  define __has_attribute(attr) false
+#endif
+
+// Platform detection
+
+// Get the definition of BSD if available
+#if BFS_USE_SYS_PARAM_H
+#  include <sys/param.h>
+#endif
+
+#ifndef __GLIBC_PREREQ
+#  define __GLIBC_PREREQ(maj, min) false
+#endif
+
+#ifndef __NetBSD_Prereq__
+#  define __NetBSD_Prereq__(maj, min, patch) false
+#endif
+
+// Fundamental utilities
+
+/**
+ * Get the length of an array.
+ */
+#define countof(array) (sizeof(array) / sizeof(0[array]))
+
+/**
+ * False sharing/destructive interference/largest cache line size.
+ */
+#ifdef __GCC_DESTRUCTIVE_SIZE
+#  define FALSE_SHARING_SIZE __GCC_DESTRUCTIVE_SIZE
+#else
+#  define FALSE_SHARING_SIZE 64
+#endif
+
+/**
+ * True sharing/constructive interference/smallest cache line size.
+ */
+#ifdef __GCC_CONSTRUCTIVE_SIZE
+#  define TRUE_SHARING_SIZE __GCC_CONSTRUCTIVE_SIZE
+#else
+#  define TRUE_SHARING_SIZE 64
+#endif
+
+/**
+ * Alignment specifier that avoids false sharing.
+ */
+#define cache_align alignas(FALSE_SHARING_SIZE)
+
+#if __COSMOPOLITAN__
+typedef long double max_align_t;
+#endif
+
+// Wrappers for attributes
+
+/**
+ * Silence warnings about switch/case fall-throughs.
+ */
+#if __has_attribute(fallthrough)
+#  define fallthru __attribute__((fallthrough))
+#else
+#  define fallthru ((void)0)
+#endif
+
+/**
+ * Silence warnings about unused declarations.
+ */
+#if __has_attribute(unused)
+#  define attr_maybe_unused __attribute__((unused))
+#else
+#  define attr_maybe_unused
+#endif
+
+/**
+ * Warn if a value is unused.
+ */
+#if __has_attribute(warn_unused_result)
+#  define attr_nodiscard __attribute__((warn_unused_result))
+#else
+#  define attr_nodiscard
+#endif
+
+/**
+ * Hint to avoid inlining a function.
+ */
+#if __has_attribute(noinline)
+#  define attr_noinline __attribute__((noinline))
+#else
+#  define attr_noinline
+#endif
+
+/**
+ * Hint that a function is unlikely to be called.
+ */
+#if __has_attribute(cold)
+#  define attr_cold attr_noinline __attribute__((cold))
+#else
+#  define attr_cold attr_noinline
+#endif
+
+/**
+ * Adds compiler warnings for bad printf()-style function calls, if supported.
+ */
+#if __has_attribute(format)
+#  define attr_printf(fmt, args) __attribute__((format(printf, fmt, args)))
+#else
+#  define attr_printf(fmt, args)
+#endif
+
+/**
+ * Annotates allocator-like functions.
+ */
+#if __has_attribute(malloc)
+#  if __GNUC__ >= 11 && !__OPTIMIZE__ // malloc(deallocator) disables inlining on GCC
+#    define attr_malloc(...) attr_nodiscard __attribute__((malloc(__VA_ARGS__)))
+#  else
+#    define attr_malloc(...) attr_nodiscard __attribute__((malloc))
+#  endif
+#else
+#  define attr_malloc(...) attr_nodiscard
+#endif
+
+/**
+ * Specifies that a function returns allocations with a given alignment.
+ */
+#if __has_attribute(alloc_align)
+#  define attr_alloc_align(param) __attribute__((alloc_align(param)))
+#else
+#  define attr_alloc_align(param)
+#endif
+
+/**
+ * Specifies that a function returns allocations with a given size.
+ */
+#if __has_attribute(alloc_size)
+#  define attr_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
+#else
+#  define attr_alloc_size(...)
+#endif
+
+/**
+ * Shorthand for attr_alloc_align() and attr_alloc_size().
+ */
+#define attr_aligned_alloc(align, ...) \
+	attr_alloc_align(align) \
+	attr_alloc_size(__VA_ARGS__)
+
+/**
+ * Check if function multiversioning via GNU indirect functions (ifunc) is supported.
+ */
+#ifndef BFS_USE_TARGET_CLONES
+#  if __has_attribute(target_clones) && (__GLIBC__ || __FreeBSD__)
+#    define BFS_USE_TARGET_CLONES true
+#  endif
+#endif
+
+/**
+ * Apply the target_clones attribute, if available.
+ */
+#if BFS_USE_TARGET_CLONES
+#  define attr_target_clones(...) __attribute__((target_clones(__VA_ARGS__)))
+#else
+#  define attr_target_clones(...)
+#endif
+
+/**
+ * Shorthand for multiple attributes at once. attr(a, b(c), d) is equivalent to
+ *
+ *     attr_a
+ *     attr_b(c)
+ *     attr_d
+ */
+#define attr(...) \
+	attr__(attr_##__VA_ARGS__, none, none, none, none, none, none, none, none, none, )
+
+/**
+ * attr() helper.  For exposition, pretend we support only 2 args, instead of 9.
+ * There are a few cases:
+ *
+ *     attr()
+ *         => attr__(attr_, none, none)
+ *         => attr_                =>
+ *            attr_none            =>
+ *            attr_too_many_none() =>
+ *
+ *     attr(a)
+ *         => attr__(attr_a, none, none)
+ *         => attr_a               => __attribute__((a))
+ *            attr_none            =>
+ *            attr_too_many_none() =>
+ *
+ *     attr(a, b(c))
+ *         => attr__(attr_a, b(c), none, none)
+ *         => attr_a                   => __attribute__((a))
+ *            attr_b(c)                => __attribute__((b(c)))
+ *            attr_too_many_none(none) =>
+ *
+ *     attr(a, b(c), d)
+ *         => attr__(attr_a, b(c), d, none, none)
+ *         => attr_a                      => __attribute__((a))
+ *            attr_b(c)                   => __attribute__((b(c)))
+ *            attr_too_many_d(none, none) => error
+ *
+ * Some attribute names are the same as standard library functions, e.g. printf.
+ * Standard libraries are permitted to define these functions as macros, like
+ *
+ *     #define printf(...) __builtin_printf(__VA_ARGS__)
+ *
+ * The token paste in
+ *
+ *     #define attr(...) attr__(attr_##__VA_ARGS__, none, none)
+ *
+ * is necessary to prevent macro expansion before evaluating attr__().
+ * Otherwise, we could get
+ *
+ *     attr(printf(1, 2))
+ *         => attr__(__builtin_printf(1, 2), none, none)
+ *         => attr____builtin_printf(1, 2)
+ *         => error
+ */
+#define attr__(a1, a2, a3, a4, a5, a6, a7, a8, a9, none, ...) \
+	a1 \
+	attr_##a2 \
+	attr_##a3 \
+	attr_##a4 \
+	attr_##a5 \
+	attr_##a6 \
+	attr_##a7 \
+	attr_##a8 \
+	attr_##a9 \
+	attr_too_many_##none(__VA_ARGS__)
+
+// Ignore `attr_none` from expanding 1-9 argument attr(a1, a2, ...)
+#define attr_none
+// Ignore `attr_` from expanding 0-argument attr()
+#define attr_
+// Only trigger an error on more than 9 arguments
+#define attr_too_many_none(...)
+
+#endif // BFS_PRELUDE_H
diff --git a/src/printf.c b/src/printf.c
index 3b8269e..4df399b 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -1,12 +1,12 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "printf.h"
 #include "alloc.h"
 #include "bfstd.h"
 #include "bftw.h"
 #include "color.h"
-#include "config.h"
 #include "ctx.h"
 #include "diag.h"
 #include "dir.h"
diff --git a/src/pwcache.c b/src/pwcache.c
index 79437d8..af8c237 100644
--- a/src/pwcache.c
+++ b/src/pwcache.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "pwcache.h"
 #include "alloc.h"
-#include "config.h"
 #include "trie.h"
 #include <errno.h>
 #include <grp.h>
diff --git a/src/sanity.h b/src/sanity.h
index 423e6ff..e168b8f 100644
--- a/src/sanity.h
+++ b/src/sanity.h
@@ -8,7 +8,7 @@
 #ifndef BFS_SANITY_H
 #define BFS_SANITY_H
 
-#include "config.h"
+#include "prelude.h"
 #include <stddef.h>
 
 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
diff --git a/src/stat.c b/src/stat.c
index 2f2743b..eca5bab 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "stat.h"
 #include "atomic.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include <errno.h>
diff --git a/src/stat.h b/src/stat.h
index 856a2ca..1fdd263 100644
--- a/src/stat.h
+++ b/src/stat.h
@@ -12,7 +12,7 @@
 #ifndef BFS_STAT_H
 #define BFS_STAT_H
 
-#include "config.h"
+#include "prelude.h"
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <time.h>
diff --git a/src/thread.c b/src/thread.c
index 200d8c3..3793896 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "thread.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include <errno.h>
 #include <pthread.h>
diff --git a/src/thread.h b/src/thread.h
index 8174fe4..db11bd8 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -8,7 +8,7 @@
 #ifndef BFS_THREAD_H
 #define BFS_THREAD_H
 
-#include "config.h"
+#include "prelude.h"
 #include <pthread.h>
 
 #if __STDC_VERSION__ < C23 && !defined(thread_local)
diff --git a/src/trie.c b/src/trie.c
index f275064..808953e 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -81,10 +81,10 @@
  * and insert intermediate singleton "jump" nodes when necessary.
  */
 
+#include "prelude.h"
 #include "trie.h"
 #include "alloc.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include "list.h"
 #include <stdint.h>
diff --git a/src/xregex.c b/src/xregex.c
index 3df27f0..c2711bc 100644
--- a/src/xregex.c
+++ b/src/xregex.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "xregex.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include "sanity.h"
 #include "thread.h"
diff --git a/src/xspawn.c b/src/xspawn.c
index 347625d..113d7ec 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "xspawn.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "list.h"
 #include <errno.h>
 #include <fcntl.h>
diff --git a/src/xspawn.h b/src/xspawn.h
index a20cbd0..6a8f54a 100644
--- a/src/xspawn.h
+++ b/src/xspawn.h
@@ -8,7 +8,7 @@
 #ifndef BFS_XSPAWN_H
 #define BFS_XSPAWN_H
 
-#include "config.h"
+#include "prelude.h"
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <unistd.h>
diff --git a/src/xtime.c b/src/xtime.c
index bcf6dd3..91ed915 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "xtime.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include <errno.h>
 #include <limits.h>
diff --git a/tests/alloc.c b/tests/alloc.c
index 54b84ba..6c0defd 100644
--- a/tests/alloc.c
+++ b/tests/alloc.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "alloc.h"
-#include "config.h"
 #include "diag.h"
 #include <errno.h>
 #include <stdlib.h>
diff --git a/tests/bfstd.c b/tests/bfstd.c
index 5e408ca..07b68b0 100644
--- a/tests/bfstd.c
+++ b/tests/bfstd.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include <errno.h>
 #include <langinfo.h>
diff --git a/tests/bit.c b/tests/bit.c
index b444e50..674d1b2 100644
--- a/tests/bit.c
+++ b/tests/bit.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "bit.h"
-#include "config.h"
 #include "diag.h"
 #include <limits.h>
 #include <stdint.h>
diff --git a/tests/ioq.c b/tests/ioq.c
index a69f2bf..ef5ee3b 100644
--- a/tests/ioq.c
+++ b/tests/ioq.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "ioq.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include "dir.h"
 #include <errno.h>
diff --git a/tests/main.c b/tests/main.c
index 281c417..429772b 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -5,10 +5,10 @@
  * Entry point for unit tests.
  */
 
+#include "prelude.h"
 #include "tests.h"
 #include "bfstd.h"
 #include "color.h"
-#include "config.h"
 #include <errno.h>
 #include <locale.h>
 #include <stdio.h>
diff --git a/tests/tests.h b/tests/tests.h
index d61ffd7..9078938 100644
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -8,7 +8,7 @@
 #ifndef BFS_TESTS_H
 #define BFS_TESTS_H
 
-#include "config.h"
+#include "prelude.h"
 #include "diag.h"
 
 /** Unit test function type. */
diff --git a/tests/trie.c b/tests/trie.c
index 2a6eb48..4667322 100644
--- a/tests/trie.c
+++ b/tests/trie.c
@@ -1,9 +1,9 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "trie.h"
-#include "config.h"
 #include "diag.h"
 #include <stdlib.h>
 #include <string.h>
diff --git a/tests/xspawn.c b/tests/xspawn.c
index fd8362e..7362aa5 100644
--- a/tests/xspawn.c
+++ b/tests/xspawn.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "alloc.h"
 #include "bfstd.h"
-#include "config.h"
 #include "dstring.h"
 #include "xspawn.h"
 #include <stdlib.h>
diff --git a/tests/xtime.c b/tests/xtime.c
index fd7aa0f..a7c63d2 100644
--- a/tests/xtime.c
+++ b/tests/xtime.c
@@ -1,10 +1,10 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "tests.h"
 #include "xtime.h"
 #include "bfstd.h"
-#include "config.h"
 #include "diag.h"
 #include <errno.h>
 #include <limits.h>
diff --git a/tests/xtouch.c b/tests/xtouch.c
index b1daec7..82d749d 100644
--- a/tests/xtouch.c
+++ b/tests/xtouch.c
@@ -1,8 +1,8 @@
 // Copyright © Tavian Barnes <tavianator@tavianator.com>
 // SPDX-License-Identifier: 0BSD
 
+#include "prelude.h"
 #include "bfstd.h"
-#include "config.h"
 #include "sanity.h"
 #include "xtime.h"
 #include <errno.h>
-- 
cgit v1.2.3


From 4a802da8d598c6fe3317e186b64a0b020cc96f01 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 24 Apr 2024 11:36:51 -0400
Subject: opt: Add missing NULL check in visit_shallow()

visit_shallow() should propagate NULL, but look_up_visitor()
dereferences expr to know which visitor to return.
---
 src/opt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'src/opt.c')

diff --git a/src/opt.c b/src/opt.c
index ffc795b..883d598 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -947,8 +947,12 @@ static struct bfs_expr *visit_shallow(struct bfs_opt *opt, struct bfs_expr *expr
 		expr = general(opt, expr, visitor);
 	}
 
+	if (!expr) {
+		return NULL;
+	}
+
 	visit_fn *specific = look_up_visitor(expr, visitor->table);
-	if (expr && specific) {
+	if (specific) {
 		expr = specific(opt, expr, visitor);
 	}
 
-- 
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