GH-121459: Streamline PyObject* to PyStackRef conversions by disallowing NULL pointers. (GH-124894)

1 files changed, 19 insertions, 13 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index a0edf17d747..228d82173e6 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1922,9 +1922,10 @@ dummy_func(
             DECREF_INPUTS();
             ERROR_IF(super == NULL, error);
             PyObject *name = GETITEM(FRAME_CO_NAMES, oparg >> 2);
-            attr = PyStackRef_FromPyObjectSteal(PyObject_GetAttr(super, name));
+            PyObject *attr_o = PyObject_GetAttr(super, name);
             Py_DECREF(super);
-            ERROR_IF(PyStackRef_IsNull(attr), error);
+            ERROR_IF(attr_o == NULL, error);
+            attr = PyStackRef_FromPyObjectSteal(attr_o);
             null = PyStackRef_NULL;
         }
 
@@ -2740,9 +2741,10 @@ dummy_func(
 
         inst(GET_ITER, (iterable -- iter)) {
             /* before: [obj]; after [getiter(obj)] */
-            iter = PyStackRef_FromPyObjectSteal(PyObject_GetIter(PyStackRef_AsPyObjectBorrow(iterable)));
+            PyObject *iter_o = PyObject_GetIter(PyStackRef_AsPyObjectBorrow(iterable));
             DECREF_INPUTS();
-            ERROR_IF(PyStackRef_IsNull(iter), error);
+            ERROR_IF(iter_o == NULL, error);
+            iter = PyStackRef_FromPyObjectSteal(iter_o);
         }
 
         inst(GET_YIELD_FROM_ITER, (iterable -- iter)) {
@@ -3052,16 +3054,18 @@ dummy_func(
             PyObject *owner_o = PyStackRef_AsPyObjectSteal(owner);
             PyObject *name = _Py_SpecialMethods[oparg].name;
             PyObject *self_or_null_o;
-            attr = PyStackRef_FromPyObjectSteal(_PyObject_LookupSpecialMethod(owner_o, name, &self_or_null_o));
-            if (PyStackRef_IsNull(attr)) {
+            PyObject *attr_o = _PyObject_LookupSpecialMethod(owner_o, name, &self_or_null_o);
+            if (attr_o == NULL) {
                 if (!_PyErr_Occurred(tstate)) {
                     _PyErr_Format(tstate, PyExc_TypeError,
                                   _Py_SpecialMethods[oparg].error,
                                   Py_TYPE(owner_o)->tp_name);
                 }
+                ERROR_IF(true, error);
             }
-            ERROR_IF(PyStackRef_IsNull(attr), error);
-            self_or_null = PyStackRef_FromPyObjectSteal(self_or_null_o);
+            attr = PyStackRef_FromPyObjectSteal(attr_o);
+            self_or_null = self_or_null_o == NULL ?
+                PyStackRef_NULL : PyStackRef_FromPyObjectSteal(self_or_null_o);
         }
 
         inst(WITH_EXCEPT_START, (exit_func, exit_self, lasti, unused, val -- exit_func, exit_self, lasti, unused, val, res)) {
@@ -3092,9 +3096,10 @@ dummy_func(
             (void)lasti; // Shut up compiler warning if asserts are off
             PyObject *stack[5] = {NULL, PyStackRef_AsPyObjectBorrow(exit_self), exc, val_o, tb};
             int has_self = !PyStackRef_IsNull(exit_self);
-            res = PyStackRef_FromPyObjectSteal(PyObject_Vectorcall(exit_func_o, stack + 2 - has_self,
-                    (3 + has_self) | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL));
-            ERROR_IF(PyStackRef_IsNull(res), error);
+            PyObject *res_o = PyObject_Vectorcall(exit_func_o, stack + 2 - has_self,
+                    (3 + has_self) | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
+            ERROR_IF(res_o == NULL, error);
+            res = PyStackRef_FromPyObjectSteal(res_o);
         }
 
         pseudo(SETUP_FINALLY, (-- unused), (HAS_ARG)) = {
@@ -4539,9 +4544,10 @@ dummy_func(
             /* If value is a unicode object, then we know the result
              * of format(value) is value itself. */
             if (!PyUnicode_CheckExact(value_o)) {
-                res = PyStackRef_FromPyObjectSteal(PyObject_Format(value_o, NULL));
+                PyObject *res_o = PyObject_Format(value_o, NULL);
                 PyStackRef_CLOSE(value);
-                ERROR_IF(PyStackRef_IsNull(res), error);
+                ERROR_IF(res_o == NULL, error);
+                res = PyStackRef_FromPyObjectSteal(res_o);
             }
             else {
                 res = value;