Vladimir Marangozov' performance hack: copy f_builtins from ancestor

if the globals are the same.

Also, when creating a dummy builtins dictionary, add "None" to it,
just to be kind.

diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 03f54dd94747b349a8404f75b372d7337712dbc1..0b9604ae71ce0b525d19e55d035033f618aad5d2 100644 (file)
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -164,9 +164,16 @@ PyFrame_New(tstate, code, globals, locals)
                PyErr_BadInternalCall();
                return NULL;
        }
-       builtins = PyDict_GetItem(globals, builtin_object);
-       if (builtins != NULL && PyModule_Check(builtins))
-               builtins = PyModule_GetDict(builtins);
+       if (back == NULL || back->f_globals != globals) {
+               builtins = PyDict_GetItem(globals, builtin_object);
+               if (builtins != NULL && PyModule_Check(builtins))
+                       builtins = PyModule_GetDict(builtins);
+       }
+       else {
+               /* If we share the globals, we share the builtins.
+                  Save a lookup and a call. */
+               builtins = back->f_builtins;
+       }
        if (builtins != NULL && !PyDict_Check(builtins))
                builtins = NULL;
        if (free_list == NULL) {
@@ -194,9 +201,13 @@ PyFrame_New(tstate, code, globals, locals)
                _Py_NewReference(f);
        }
        if (builtins == NULL) {
+               /* No builtins!  Make up a minimal one. */
                builtins = PyDict_New();
                if (builtins == NULL)
                        return NULL;
+               /* Give them 'None', at least. */
+               if (PyDict_SetItemString(builtins, "None", Py_None) < 0)
+                       return NULL;
        }
        else
                Py_XINCREF(builtins);