gh-111789: Simplify bytecodes.c by using PyDict_GetItemRef() (GH-111978)

Author: serhiy-storchaka

Python/bytecodes.c

@@ -643,16 +643,12 @@ dummy_func(
         inst(BINARY_SUBSCR_DICT, (unused/1, dict, sub -- res)) {
             DEOPT_IF(!PyDict_CheckExact(dict));
             STAT_INC(BINARY_SUBSCR, hit);
-            res = PyDict_GetItemWithError(dict, sub);
-            if (res == NULL) {
-                if (!_PyErr_Occurred(tstate)) {
-                    _PyErr_SetKeyError(sub);
-                }
-                DECREF_INPUTS();
-                ERROR_IF(true, error);
+            int rc = PyDict_GetItemRef(dict, sub, &res);
+            if (rc == 0) {
+                _PyErr_SetKeyError(sub);
             }
-            Py_INCREF(res);  // Do this before DECREF'ing dict, sub
             DECREF_INPUTS();
+            ERROR_IF(rc <= 0, error); // not found or error
         }
 
         inst(BINARY_SUBSCR_GETITEM, (unused/1, container, sub -- unused)) {
@@ -1349,14 +1345,10 @@ dummy_func(
                 GOTO_ERROR(error);
             }
             if (v == NULL) {
-                v = PyDict_GetItemWithError(GLOBALS(), name);
-                if (v != NULL) {
-                    Py_INCREF(v);
-                }
-                else if (_PyErr_Occurred(tstate)) {
+                if (PyDict_GetItemRef(GLOBALS(), name, &v) < 0) {
                     GOTO_ERROR(error);
                 }
-                else {
+                if (v == NULL) {
                     if (PyMapping_GetOptionalItem(BUILTINS(), name, &v) < 0) {
                         GOTO_ERROR(error);
                     }
@@ -1383,14 +1375,10 @@ dummy_func(
                 GOTO_ERROR(error);
             }
             if (v == NULL) {
-                v = PyDict_GetItemWithError(GLOBALS(), name);
-                if (v != NULL) {
-                    Py_INCREF(v);
-                }
-                else if (_PyErr_Occurred(tstate)) {
+                if (PyDict_GetItemRef(GLOBALS(), name, &v) < 0) {
                     GOTO_ERROR(error);
                 }
-                else {
+                if (v == NULL) {
                     if (PyMapping_GetOptionalItem(BUILTINS(), name, &v) < 0) {
                         GOTO_ERROR(error);
                     }
@@ -1663,34 +1651,17 @@ dummy_func(
                 ERROR_IF(true, error);
             }
             /* check if __annotations__ in locals()... */
-            if (PyDict_CheckExact(LOCALS())) {
-                ann_dict = _PyDict_GetItemWithError(LOCALS(),
-                                                    &_Py_ID(__annotations__));
-                if (ann_dict == NULL) {
-                    ERROR_IF(_PyErr_Occurred(tstate), error);
-                    /* ...if not, create a new one */
-                    ann_dict = PyDict_New();
-                    ERROR_IF(ann_dict == NULL, error);
-                    err = PyDict_SetItem(LOCALS(), &_Py_ID(__annotations__),
-                                         ann_dict);
-                    Py_DECREF(ann_dict);
-                    ERROR_IF(err, error);
-                }
+            ERROR_IF(PyMapping_GetOptionalItem(LOCALS(), &_Py_ID(__annotations__), &ann_dict) < 0, error);
+            if (ann_dict == NULL) {
+                ann_dict = PyDict_New();
+                ERROR_IF(ann_dict == NULL, error);
+                err = PyObject_SetItem(LOCALS(), &_Py_ID(__annotations__),
+                                       ann_dict);
+                Py_DECREF(ann_dict);
+                ERROR_IF(err, error);
             }
             else {
-                /* do the same if locals() is not a dict */
-                ERROR_IF(PyMapping_GetOptionalItem(LOCALS(), &_Py_ID(__annotations__), &ann_dict) < 0, error);
-                if (ann_dict == NULL) {
-                    ann_dict = PyDict_New();
-                    ERROR_IF(ann_dict == NULL, error);
-                    err = PyObject_SetItem(LOCALS(), &_Py_ID(__annotations__),
-                                           ann_dict);
-                    Py_DECREF(ann_dict);
-                    ERROR_IF(err, error);
-                }
-                else {
-                    Py_DECREF(ann_dict);
-                }
+                Py_DECREF(ann_dict);
             }
         }