gh-87729: specialize LOAD_SUPER_ATTR_METHOD (#103809)

1 files changed, 58 insertions, 26 deletions

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 09ea566..9194eba 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -9380,22 +9380,19 @@ super_repr(PyObject *self)
             su->type ? su->type->tp_name : "NULL");
 }
 
-// if `method` is non-NULL, we are looking for a method descriptor,
-// and setting `*method` to 1 means we found one.
+/* Do a super lookup without executing descriptors or falling back to getattr
+on the super object itself.
+
+May return NULL with or without an exception set, like PyDict_GetItemWithError. */
 static PyObject *
-do_super_lookup(superobject *su, PyTypeObject *su_type, PyObject *su_obj,
-                PyTypeObject *su_obj_type, PyObject *name, int *method)
+_super_lookup_descr(PyTypeObject *su_type, PyTypeObject *su_obj_type, PyObject *name)
 {
     PyObject *mro, *res;
     Py_ssize_t i, n;
-    int temp_su = 0;
-
-    if (su_obj_type == NULL)
-        goto skip;
 
     mro = su_obj_type->tp_mro;
     if (mro == NULL)
-        goto skip;
+        return NULL;
 
     assert(PyTuple_Check(mro));
     n = PyTuple_GET_SIZE(mro);
@@ -9407,7 +9404,7 @@ do_super_lookup(superobject *su, PyTypeObject *su_type, PyObject *su_obj,
     }
     i++;  /* skip su->type (if any)  */
     if (i >= n)
-        goto skip;
+        return NULL;
 
     /* keep a strong reference to mro because su_obj_type->tp_mro can be
        replaced during PyDict_GetItemWithError(dict, name)  */
@@ -9420,22 +9417,6 @@ do_super_lookup(superobject *su, PyTypeObject *su_type, PyObject *su_obj,
         res = PyDict_GetItemWithError(dict, name);
         if (res != NULL) {
             Py_INCREF(res);
-            if (method && _PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
-                *method = 1;
-            }
-            else {
-                descrgetfunc f = Py_TYPE(res)->tp_descr_get;
-                if (f != NULL) {
-                    PyObject *res2;
-                    res2 = f(res,
-                        /* Only pass 'obj' param if this is instance-mode super
-                        (See SF ID #743627)  */
-                        (su_obj == (PyObject *)su_obj_type) ? NULL : su_obj,
-                        (PyObject *)su_obj_type);
-                    Py_SETREF(res, res2);
-                }
-            }
-
             Py_DECREF(mro);
             return res;
         }
@@ -9447,6 +9428,45 @@ do_super_lookup(superobject *su, PyTypeObject *su_type, PyObject *su_obj,
         i++;
     } while (i < n);
     Py_DECREF(mro);
+    return NULL;
+}
+
+// if `method` is non-NULL, we are looking for a method descriptor,
+// and setting `*method = 1` means we found one.
+static PyObject *
+do_super_lookup(superobject *su, PyTypeObject *su_type, PyObject *su_obj,
+                PyTypeObject *su_obj_type, PyObject *name, int *method)
+{
+    PyObject *res;
+    int temp_su = 0;
+
+    if (su_obj_type == NULL) {
+        goto skip;
+    }
+
+    res = _super_lookup_descr(su_type, su_obj_type, name);
+    if (res != NULL) {
+        if (method && _PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
+            *method = 1;
+        }
+        else {
+            descrgetfunc f = Py_TYPE(res)->tp_descr_get;
+            if (f != NULL) {
+                PyObject *res2;
+                res2 = f(res,
+                    /* Only pass 'obj' param if this is instance-mode super
+                    (See SF ID #743627)  */
+                    (su_obj == (PyObject *)su_obj_type) ? NULL : su_obj,
+                    (PyObject *)su_obj_type);
+                Py_SETREF(res, res2);
+            }
+        }
+
+        return res;
+    }
+    else if (PyErr_Occurred()) {
+        return NULL;
+    }
 
   skip:
     if (su == NULL) {
@@ -9544,6 +9564,18 @@ _PySuper_Lookup(PyTypeObject *su_type, PyObject *su_obj, PyObject *name, int *me
     return res;
 }
 
+PyObject *
+_PySuper_LookupDescr(PyTypeObject *su_type, PyObject *su_obj, PyObject *name)
+{
+    PyTypeObject *su_obj_type = supercheck(su_type, su_obj);
+    if (su_obj_type == NULL) {
+        return NULL;
+    }
+    PyObject *res = _super_lookup_descr(su_type, su_obj_type, name);
+    Py_DECREF(su_obj_type);
+    return res;
+}
+
 static PyObject *
 super_descr_get(PyObject *self, PyObject *obj, PyObject *type)
 {