From 4a36bb92a5bbdc41965a6d2c6eae6cdca5983474 Mon Sep 17 00:00:00 2001 From: Tavian Barnes 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/expr.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) (limited to 'src/expr.c') 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; -- cgit v1.2.3