Use iteration instead of recursion

diff --git a/Zend/zend_ast.c b/Zend/zend_ast.c
index e4ffbed60751d6be9a22b766f57719b26327a1ec..aae042f8206b3494f619e76e1acde641e3361257 100644 (file)
--- a/Zend/zend_ast.c
+++ b/Zend/zend_ast.c
@@ -754,7 +754,9 @@ ZEND_API zend_ast_ref * ZEND_FASTCALL zend_ast_copy(zend_ast *ast)
        return ref;
 }
 
-ZEND_API void ZEND_FASTCALL zend_ast_destroy(zend_ast *ast) {
+ZEND_API void ZEND_FASTCALL zend_ast_destroy(zend_ast *ast)
+{
+tail_call:
        if (!ast) {
                return;
        }
@@ -762,17 +764,23 @@ ZEND_API void ZEND_FASTCALL zend_ast_destroy(zend_ast *ast) {
        if (EXPECTED(ast->kind >= ZEND_AST_VAR)) {
                uint32_t i, children = zend_ast_get_num_children(ast);
 
-               for (i = 0; i < children; i++) {
+               for (i = 1; i < children; i++) {
                        zend_ast_destroy(ast->child[i]);
                }
+               ast = ast->child[0];
+               goto tail_call;
        } else if (EXPECTED(ast->kind == ZEND_AST_ZVAL)) {
                zval_ptr_dtor_nogc(zend_ast_get_zval(ast));
        } else if (EXPECTED(zend_ast_is_list(ast))) {
                zend_ast_list *list = zend_ast_get_list(ast);
-               uint32_t i;
+               if (list->children) {
+                       uint32_t i;
 
-               for (i = 0; i < list->children; i++) {
-                       zend_ast_destroy(list->child[i]);
+                       for (i = 1; i < list->children; i++) {
+                               zend_ast_destroy(list->child[i]);
+                       }
+                       ast = list->child[0];
+                       goto tail_call;
                }
        } else if (EXPECTED(ast->kind == ZEND_AST_CONSTANT)) {
                zend_string_release(zend_ast_get_constant_name(ast));
@@ -788,7 +796,8 @@ ZEND_API void ZEND_FASTCALL zend_ast_destroy(zend_ast *ast) {
                zend_ast_destroy(decl->child[0]);
                zend_ast_destroy(decl->child[1]);
                zend_ast_destroy(decl->child[2]);
-               zend_ast_destroy(decl->child[3]);
+               ast = decl->child[3];
+               goto tail_call;
        }
 }