ext/pdo: Convert _pdo_dbh_t query_stmt_zval to a zend_object pointer (php#17742)

This saves 8 bytes

Author: Girgias

ext/pdo/pdo_dbh.c

@@ -1248,7 +1248,7 @@ PHP_METHOD(PDO, query)
 		}
 		/* something broke */
 		dbh->query_stmt = stmt;
-		ZVAL_OBJ(&dbh->query_stmt_zval, Z_OBJ_P(return_value));
+		dbh->query_stmt_obj = Z_OBJ_P(return_value);
 		GC_DELREF(stmt->database_object_handle);
 		stmt->database_object_handle = NULL;
 		PDO_HANDLE_STMT_ERR();
@@ -1468,7 +1468,8 @@ static void dbh_free(pdo_dbh_t *dbh, bool free_persistent)
 	int i;
 
 	if (dbh->query_stmt) {
-		zval_ptr_dtor(&dbh->query_stmt_zval);
+		OBJ_RELEASE(dbh->query_stmt_obj);
+		dbh->query_stmt_obj = NULL;
 		dbh->query_stmt = NULL;
 	}
 

ext/pdo/php_pdo_driver.h

@@ -499,7 +499,7 @@ struct _pdo_dbh_t {
 	 * This will allow us to report the correct error message
 	 * when PDO::query() fails */
 	pdo_stmt_t *query_stmt;
-	zval query_stmt_zval;
+	zend_object *query_stmt_obj;
 
 	/* defaults for fetches */
 	enum pdo_fetch_type default_fetch_type;

ext/pdo/php_pdo_error.h

@@ -26,7 +26,8 @@ PDO_API void pdo_handle_error(pdo_dbh_t *dbh, pdo_stmt_t *stmt);
 	memcpy(dbh->error_code, PDO_ERR_NONE, sizeof(PDO_ERR_NONE)); \
 	if (dbh->query_stmt) { \
 		dbh->query_stmt = NULL; \
-		zval_ptr_dtor(&dbh->query_stmt_zval); \
+		OBJ_RELEASE(dbh->query_stmt_obj); \
+		dbh->query_stmt_obj = NULL; \
 	} \
 } while (0)
 #define PDO_STMT_CLEAR_ERR() do { \