gh-100288: Specialise LOAD_ATTR_METHOD for managed dictionaries (GH-100289)

1 files changed, 25 insertions, 0 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index c0b625b..c2f6a7a 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2718,6 +2718,31 @@ dummy_func(
         }
 
         // error: LOAD_ATTR has irregular stack effect
+        inst(LOAD_ATTR_METHOD_MANAGED_DICT) {
+            assert(cframe.use_tracing == 0);
+            PyObject *self = TOP();
+            PyTypeObject *self_cls = Py_TYPE(self);
+            _PyLoadMethodCache *cache = (_PyLoadMethodCache *)next_instr;
+            uint32_t type_version = read_u32(cache->type_version);
+            assert(type_version != 0);
+            DEOPT_IF(self_cls->tp_version_tag != type_version, LOAD_ATTR)
+            assert(self_cls->tp_flags & Py_TPFLAGS_MANAGED_DICT);
+            PyDictOrValues dorv = *_PyObject_DictOrValuesPointer(self);
+            DEOPT_IF(_PyDictOrValues_IsValues(dorv), LOAD_ATTR);
+            PyObject *dict = _PyDictOrValues_GetDict(dorv);
+            PyDictKeysObject *keys = (dict == NULL) ? NULL : ((PyDictObject *)dict)->ma_keys;
+            // Note: cache->keys_version can be 0 when dict is NULL.
+            DEOPT_IF(keys != NULL && keys->dk_version != read_u32(cache->keys_version), LOAD_ATTR);
+            STAT_INC(LOAD_ATTR, hit);
+            PyObject *res = read_obj(cache->descr);
+            assert(res != NULL);
+            assert(_PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR));
+            SET_TOP(Py_NewRef(res));
+            PUSH(self);
+            JUMPBY(INLINE_CACHE_ENTRIES_LOAD_ATTR);
+        }
+
+        // error: LOAD_ATTR has irregular stack effect
         inst(LOAD_ATTR_METHOD_WITH_DICT) {
             /* Can be either a managed dict, or a tp_dictoffset offset.*/
             assert(cframe.use_tracing == 0);