pythongh-103951: enable optimization for fast attribute access on module subclasses (pythonGH-126264)

Co-authored-by: Nicolas Tessore <[email protected]>

Author: 2 people

Misc/NEWS.d/next/Core_and_Builtins/2024-11-01-09-58-06.gh-issue-103951.6qduwj.rst

@@ -0,0 +1,2 @@
+Relax optimization requirements to allow fast attribute access to module
+subclasses.

Python/bytecodes.c

@@ -2132,7 +2132,7 @@ dummy_func(
 
         op(_CHECK_ATTR_MODULE, (dict_version/2, owner -- owner)) {
             PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
-            DEOPT_IF(!PyModule_CheckExact(owner_o));
+            DEOPT_IF(Py_TYPE(owner_o)->tp_getattro != PyModule_Type.tp_getattro);
             PyDictObject *dict = (PyDictObject *)((PyModuleObject *)owner_o)->md_dict;
             assert(dict != NULL);
             DEOPT_IF(dict->ma_keys->dk_version != dict_version);

Python/executor_cases.c.h

@@ -1219,7 +1219,7 @@ _Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *nam
         SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OTHER);
         fail = true;
     }
-    else if (PyModule_CheckExact(owner)) {
+    else if (Py_TYPE(owner)->tp_getattro == PyModule_Type.tp_getattro) {
         fail = specialize_module_load_attr(owner, instr, name);
     }
     else if (PyType_Check(owner)) {