Issue #14383: Add _PyDict_GetItemId() and _PyDict_SetItemId() functions

These functions simplify the usage of static constant Unicode strings.
Generalize the usage of _Py_Identifier in ceval.c and typeobject.c.

Include/dictobject.h

@@ -155,7 +155,9 @@ PyAPI_FUNC(int) PyDict_MergeFromSeq2(PyObject *d,
                                            int override);
 
 PyAPI_FUNC(PyObject *) PyDict_GetItemString(PyObject *dp, const char *key);
+PyAPI_FUNC(PyObject *) _PyDict_GetItemId(PyObject *dp, struct _Py_Identifier *key);
 PyAPI_FUNC(int) PyDict_SetItemString(PyObject *dp, const char *key, PyObject *item);
+PyAPI_FUNC(int) _PyDict_SetItemId(PyObject *dp, struct _Py_Identifier *key, PyObject *item);
 PyAPI_FUNC(int) PyDict_DelItemString(PyObject *dp, const char *key);
 
 #ifdef __cplusplus

Objects/dictobject.c

@@ -2198,6 +2198,16 @@ PyTypeObject PyDict_Type = {
     PyObject_GC_Del,                            /* tp_free */
 };
 
+PyObject *
+_PyDict_GetItemId(PyObject *dp, struct _Py_Identifier *key)
+{
+    PyObject *kv;
+    kv = _PyUnicode_FromId(key); /* borrowed */
+    if (kv == NULL)
+        return NULL;
+    return PyDict_GetItem(dp, kv);
+}
+
 /* For backward compatibility with old dictionary interface */
 
 PyObject *
@@ -2212,6 +2222,16 @@ PyDict_GetItemString(PyObject *v, const char *key)
     return rv;
 }
 
+int
+_PyDict_SetItemId(PyObject *v, struct _Py_Identifier *key, PyObject *item)
+{
+    PyObject *kv;
+    kv = _PyUnicode_FromId(key); /* borrowed */
+    if (kv == NULL)
+        return -1;
+    return PyDict_SetItem(v, kv, item);
+}
+
 int
 PyDict_SetItemString(PyObject *v, const char *key, PyObject *item)
 {

Python/ceval.c

@@ -822,6 +822,8 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
     PyObject *names;
     PyObject *consts;
 
+    _Py_IDENTIFIER(__ltrace__);
+
 /* Computed GOTOs, or
        the-optimization-commonly-but-improperly-known-as-"threaded code"
    using gcc's labels-as-values extension
@@ -1198,7 +1200,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
     }
 
 #ifdef LLTRACE
-    lltrace = PyDict_GetItemString(f->f_globals, "__lltrace__") != NULL;
+    lltrace = _PyDict_GetItemId(f->f_globals, &PyId___ltrace__) != NULL;
 #endif
 
     why = WHY_NOT;
@@ -1926,8 +1928,9 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
             break;
 
         TARGET(LOAD_BUILD_CLASS)
-            x = PyDict_GetItemString(f->f_builtins,
-                                     "__build_class__");
+        {
+            _Py_IDENTIFIER(__build_class__);
+            x = _PyDict_GetItemId(f->f_builtins, &PyId___build_class__);
             if (x == NULL) {
                 PyErr_SetString(PyExc_ImportError,
                                 "__build_class__ not found");
@@ -1936,6 +1939,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
             Py_INCREF(x);
             PUSH(x);
             break;
+        }
 
         TARGET(STORE_NAME)
             w = GETITEM(names, oparg);
@@ -2283,8 +2287,10 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
             DISPATCH();
 
         TARGET(IMPORT_NAME)
+        {
+            _Py_IDENTIFIER(__import__);
             w = GETITEM(names, oparg);
-            x = PyDict_GetItemString(f->f_builtins, "__import__");
+            x = _PyDict_GetItemId(f->f_builtins, &PyId___import__);
             if (x == NULL) {
                 PyErr_SetString(PyExc_ImportError,
                                 "__import__ not found");
@@ -2325,6 +2331,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
             SET_TOP(x);
             if (x != NULL) DISPATCH();
             break;
+        }
 
         TARGET(IMPORT_STAR)
             v = POP();