Stop copying internal functions into each thread (php#10517)

* Stop copying internal functions into each thread

It seems we don't copy internal methods for a long time, so this
shouldn't be a problem. We had to copy functions in PHP-5 times, but it
seems we just forgot to remove this.

It's possible that some third-part extensions (e.g. profilers, tracers,
debuggers) modify internal functions. After this change that may cause
race conditions in ZTS build (but we already jave the same behavior for
internal methods). Observer API should provide necesssary functionality
to avoid shared structures modification.

* Remove unused function

Author: dstogov

Zend/zend.c

@@ -674,69 +674,6 @@ static void auto_global_dtor(zval *zv) /* {{{ */
 /* }}} */
 
 #ifdef ZTS
-static void function_copy_ctor(zval *zv) /* {{{ */
-{
-	zend_function *old_func = Z_FUNC_P(zv);
-	zend_function *func;
-
-	if (old_func->type == ZEND_USER_FUNCTION) {
-		ZEND_ASSERT(old_func->op_array.fn_flags & ZEND_ACC_IMMUTABLE);
-		return;
-	}
-	func = pemalloc(sizeof(zend_internal_function), 1);
-	Z_FUNC_P(zv) = func;
-	memcpy(func, old_func, sizeof(zend_internal_function));
-	function_add_ref(func);
-	if ((old_func->common.fn_flags & (ZEND_ACC_HAS_RETURN_TYPE|ZEND_ACC_HAS_TYPE_HINTS))
-	 && old_func->common.arg_info) {
-		uint32_t i;
-		uint32_t num_args = old_func->common.num_args + 1;
-		zend_arg_info *arg_info = old_func->common.arg_info - 1;
-		zend_arg_info *new_arg_info;
-
-		if (old_func->common.fn_flags & ZEND_ACC_VARIADIC) {
-			num_args++;
-		}
-		new_arg_info = pemalloc(sizeof(zend_arg_info) * num_args, 1);
-		memcpy(new_arg_info, arg_info, sizeof(zend_arg_info) * num_args);
-		for (i = 0 ; i < num_args; i++) {
-			if (ZEND_TYPE_HAS_LIST(arg_info[i].type)) {
-				zend_type_list *old_list = ZEND_TYPE_LIST(arg_info[i].type);
-				zend_type_list *new_list = pemalloc(ZEND_TYPE_LIST_SIZE(old_list->num_types), 1);
-				memcpy(new_list, old_list, ZEND_TYPE_LIST_SIZE(old_list->num_types));
-				ZEND_TYPE_SET_PTR(new_arg_info[i].type, new_list);
-
-				zend_type *list_type;
-				ZEND_TYPE_LIST_FOREACH(new_list, list_type) {
-					zend_string *name = zend_string_dup(ZEND_TYPE_NAME(*list_type), 1);
-					ZEND_TYPE_SET_PTR(*list_type, name);
-				} ZEND_TYPE_LIST_FOREACH_END();
-			} else if (ZEND_TYPE_HAS_NAME(arg_info[i].type)) {
-				zend_string *name = zend_string_dup(ZEND_TYPE_NAME(arg_info[i].type), 1);
-				ZEND_TYPE_SET_PTR(new_arg_info[i].type, name);
-			}
-		}
-		func->common.arg_info = new_arg_info + 1;
-	}
-	if (old_func->common.attributes) {
-		zend_attribute *old_attr;
-
-		func->common.attributes = NULL;
-
-		ZEND_HASH_PACKED_FOREACH_PTR(old_func->common.attributes, old_attr) {
-			uint32_t i;
-			zend_attribute *attr;
-
-			attr = zend_add_attribute(&func->common.attributes, old_attr->name, old_attr->argc, old_attr->flags, old_attr->offset, old_attr->lineno);
-
-			for (i = 0 ; i < old_attr->argc; i++) {
-				ZVAL_DUP(&attr->args[i].value, &old_attr->args[i].value);
-			}
-		} ZEND_HASH_FOREACH_END();
-	}
-}
-/* }}} */
-
 static void auto_global_copy_ctor(zval *zv) /* {{{ */
 {
 	zend_auto_global *old_ag = (zend_auto_global *) Z_PTR_P(zv);
@@ -756,7 +693,8 @@ static void compiler_globals_ctor(zend_compiler_globals *compiler_globals) /* {{
 
 	compiler_globals->function_table = (HashTable *) malloc(sizeof(HashTable));
 	zend_hash_init(compiler_globals->function_table, 1024, NULL, ZEND_FUNCTION_DTOR, 1);
-	zend_hash_copy(compiler_globals->function_table, global_function_table, function_copy_ctor);
+	zend_hash_copy(compiler_globals->function_table, global_function_table, NULL);
+	compiler_globals->copied_functions_count = zend_hash_num_elements(compiler_globals->function_table);
 
 	compiler_globals->class_table = (HashTable *) malloc(sizeof(HashTable));
 	zend_hash_init(compiler_globals->class_table, 64, NULL, ZEND_CLASS_DTOR, 1);
@@ -790,6 +728,21 @@ static void compiler_globals_ctor(zend_compiler_globals *compiler_globals) /* {{
 static void compiler_globals_dtor(zend_compiler_globals *compiler_globals) /* {{{ */
 {
 	if (compiler_globals->function_table != GLOBAL_FUNCTION_TABLE) {
+		uint32_t n = compiler_globals->copied_functions_count;
+
+	    /* Prevent destruction of functions copied from the main process context */
+		if (zend_hash_num_elements(compiler_globals->function_table) <= n) {
+			compiler_globals->function_table->nNumUsed = 0;
+		} else {
+			Bucket *p = compiler_globals->function_table->arData;
+
+			compiler_globals->function_table->nNumOfElements -= n;
+			while (n != 0) {
+				ZVAL_UNDEF(&p->val);
+				p++;
+				n--;
+			}
+		}
 		zend_hash_destroy(compiler_globals->function_table);
 		free(compiler_globals->function_table);
 	}

Zend/zend_globals.h

@@ -144,6 +144,9 @@ struct _zend_compiler_globals {
 	uint32_t rtd_key_counter;
 
 	zend_stack short_circuiting_opnums;
+#ifdef ZTS
+	uint32_t copied_functions_count;
+#endif
 };