diff options
Diffstat (limited to 'src/opt.c')
| -rw-r--r-- | src/opt.c | 64 |
1 files changed, 46 insertions, 18 deletions
@@ -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" @@ -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); } @@ -1084,7 +1088,7 @@ static struct bfs_expr *annotate_and(struct bfs_opt *opt, struct bfs_expr *expr, expr->cost = 0.0; expr->probability = 1.0; - for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) { + for_expr (child, expr) { expr->pure &= child->pure; expr->always_true &= child->always_true; expr->always_false |= child->always_false; @@ -1103,7 +1107,7 @@ static struct bfs_expr *annotate_or(struct bfs_opt *opt, struct bfs_expr *expr, expr->cost = 0.0; float false_prob = 1.0; - for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) { + for_expr (child, expr) { expr->pure &= child->pure; expr->always_true |= child->always_true; expr->always_false &= child->always_false; @@ -1120,7 +1124,7 @@ static struct bfs_expr *annotate_comma(struct bfs_opt *opt, struct bfs_expr *exp expr->pure = true; expr->cost = 0.0; - for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) { + for_expr (child, expr) { expr->pure &= child->pure; expr->always_true = child->always_true; expr->always_false = child->always_false; @@ -1786,7 +1790,7 @@ static struct bfs_expr *data_flow_leave(struct bfs_opt *opt, struct bfs_expr *ex if (df_is_bottom(&opt->after_false)) { if (!expr->pure) { expr->always_true = true; - expr->probability = 0.0; + expr->probability = 1.0; } 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"); @@ -1915,7 +1919,7 @@ static struct bfs_expr *simplify_not(struct bfs_opt *opt, struct bfs_expr *expr, 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) { + for_expr (child, expr) { if (child->eval_fn == eval_not) { ++removed; } else { @@ -1964,7 +1968,7 @@ static struct bfs_expr *first_ignorable(struct bfs_opt *opt, struct bfs_expr *ex } struct bfs_expr *ret = NULL; - for (struct bfs_expr *child = bfs_expr_children(expr); child; child = child->next) { + for_expr (child, expr) { if (!child->pure) { ret = NULL; } else if (!ret) { @@ -2172,17 +2176,20 @@ 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) { +/** An expression predicate. */ +typedef bool expr_pred(const struct bfs_expr *expr); + +/** Estimate the odds that a matching expression will be evaluated. */ +static float estimate_odds(const struct bfs_expr *expr, expr_pred *pred) { + if (pred(expr)) { return 1.0; } - float nostat_odds = 1.0; + float nonmatch_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; + for_expr (child, expr) { + float child_odds = estimate_odds(child, pred); + nonmatch_odds *= 1.0 - reached_odds * child_odds; if (expr->eval_fn == eval_and) { reached_odds *= child->probability; @@ -2191,7 +2198,12 @@ static float expr_stat_odds(struct bfs_expr *expr) { } } - return 1.0 - nostat_odds; + return 1.0 - nonmatch_odds; +} + +/** Whether an expression calls stat(). */ +static bool calls_stat(const struct bfs_expr *expr) { + return expr->calls_stat; } /** Estimate the odds of calling stat(). */ @@ -2200,15 +2212,20 @@ static float estimate_stat_odds(struct bfs_ctx *ctx) { return 1.0; } - float nostat_odds = 1.0 - expr_stat_odds(ctx->exclude); + float nostat_odds = 1.0 - estimate_odds(ctx->exclude, calls_stat); float reached_odds = 1.0 - ctx->exclude->probability; - float expr_odds = expr_stat_odds(ctx->expr); + float expr_odds = estimate_odds(ctx->expr, calls_stat); nostat_odds *= 1.0 - reached_odds * expr_odds; return 1.0 - nostat_odds; } +/** Matches -(exec|ok) ... \; */ +static bool single_exec(const struct bfs_expr *expr) { + return expr->eval_fn == eval_exec && !(expr->exec->flags & BFS_EXEC_MULTI); +} + int bfs_optimize(struct bfs_ctx *ctx) { bfs_ctx_dump(ctx, DEBUG_OPT); @@ -2287,6 +2304,17 @@ int bfs_optimize(struct bfs_ctx *ctx) { opt_leave(&opt, "eager stat cost: ${ylw}%g${rs}\n", eager_cost); } +#ifndef POSIX_SPAWN_SETRLIMIT + // If bfs_spawn_setrlimit() would force us to use fork() over + // posix_spawn(), the extra cost may outweigh the benefit of a + // higher RLIMIT_NOFILE + float single_exec_odds = estimate_odds(ctx->expr, single_exec); + if (single_exec_odds >= 0.5) { + opt_enter(&opt, "single ${blu}-exec${rs} odds: ${ylw}%g${rs}\n", single_exec_odds); + ctx->raise_nofile = false; + opt_leave(&opt, "not raising RLIMIT_NOFILE\n"); + } +#endif } opt_leave(&opt, NULL); |