dict.get() and dict.setdefault() now use AC

Issue #29311: dict.get() and dict.setdefault() methods now use Argument Clinic
to parse arguments. Their calling convention changes from METH_VARARGS to
METH_FASTCALL which avoids the creation of a temporary tuple.

The signature of docstrings is also enhanced. For example,
    get(...)
becomes:
    get(self, key, default=None, /)

Objects/clinic/dictobject.c.h

@@ -44,4 +44,72 @@ PyDoc_STRVAR(dict___contains____doc__,
 
 #define DICT___CONTAINS___METHODDEF    \
     {"__contains__", (PyCFunction)dict___contains__, METH_O|METH_COEXIST, dict___contains____doc__},
-/*[clinic end generated code: output=69f3d767ed44e8ec input=a9049054013a1b77]*/
+
+PyDoc_STRVAR(dict_get__doc__,
+"get($self, key, default=None, /)\n"
+"--\n"
+"\n"
+"D.get(key[, default]) -> D[key] if key in D, else default.");
+
+#define DICT_GET_METHODDEF    \
+    {"get", (PyCFunction)dict_get, METH_FASTCALL, dict_get__doc__},
+
+static PyObject *
+dict_get_impl(PyDictObject *self, PyObject *key, PyObject *failobj);
+
+static PyObject *
+dict_get(PyDictObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    PyObject *key;
+    PyObject *failobj = Py_None;
+
+    if (!_PyArg_UnpackStack(args, nargs, "get",
+        1, 2,
+        &key, &failobj)) {
+        goto exit;
+    }
+
+    if (!_PyArg_NoStackKeywords("get", kwnames)) {
+        goto exit;
+    }
+    return_value = dict_get_impl(self, key, failobj);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(dict_setdefault__doc__,
+"setdefault($self, key, default=None, /)\n"
+"--\n"
+"\n"
+"D.get(key,default), also set D[key]=default if key not in D.");
+
+#define DICT_SETDEFAULT_METHODDEF    \
+    {"setdefault", (PyCFunction)dict_setdefault, METH_FASTCALL, dict_setdefault__doc__},
+
+static PyObject *
+dict_setdefault_impl(PyDictObject *self, PyObject *key, PyObject *defaultobj);
+
+static PyObject *
+dict_setdefault(PyDictObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    PyObject *key;
+    PyObject *defaultobj = Py_None;
+
+    if (!_PyArg_UnpackStack(args, nargs, "setdefault",
+        1, 2,
+        &key, &defaultobj)) {
+        goto exit;
+    }
+
+    if (!_PyArg_NoStackKeywords("setdefault", kwnames)) {
+        goto exit;
+    }
+    return_value = dict_setdefault_impl(self, key, defaultobj);
+
+exit:
+    return return_value;
+}
+/*[clinic end generated code: output=1b0cea84b4b6989e input=a9049054013a1b77]*/

Objects/dictobject.c

@@ -2787,25 +2787,31 @@ dict___contains__(PyDictObject *self, PyObject *key)
     Py_RETURN_TRUE;
 }
 
+/*[clinic input]
+dict.get
+
+    key: object
+    default as failobj: object = None
+    /
+
+D.get(key[, default]) -> D[key] if key in D, else default.
+[clinic start generated code]*/
+
 static PyObject *
-dict_get(PyDictObject *mp, PyObject *args)
+dict_get_impl(PyDictObject *self, PyObject *key, PyObject *failobj)
+/*[clinic end generated code: output=c4a84a7ddbca9b7b input=7c976a78f258e915]*/
 {
-    PyObject *key;
-    PyObject *failobj = Py_None;
     PyObject *val = NULL;
     Py_hash_t hash;
     Py_ssize_t ix;
 
-    if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &failobj))
-        return NULL;
-
     if (!PyUnicode_CheckExact(key) ||
         (hash = ((PyASCIIObject *) key)->hash) == -1) {
         hash = PyObject_Hash(key);
         if (hash == -1)
             return NULL;
     }
-    ix = (mp->ma_keys->dk_lookup)(mp, key, hash, &val, NULL);
+    ix = (self->ma_keys->dk_lookup) (self, key, hash, &val, NULL);
     if (ix == DKIX_ERROR)
         return NULL;
     if (ix == DKIX_EMPTY || val == NULL) {
@@ -2899,16 +2905,23 @@ PyDict_SetDefault(PyObject *d, PyObject *key, PyObject *defaultobj)
     return value;
 }
 
+/*[clinic input]
+dict.setdefault
+
+    key: object
+    default as defaultobj: object = None
+    /
+
+D.get(key,default), also set D[key]=default if key not in D.
+[clinic start generated code]*/
+
 static PyObject *
-dict_setdefault(PyDictObject *mp, PyObject *args)
+dict_setdefault_impl(PyDictObject *self, PyObject *key, PyObject *defaultobj)
+/*[clinic end generated code: output=692f85384b0b292e input=178f0c81d496d5cd]*/
 {
-    PyObject *key, *val;
+    PyObject *val;
-    PyObject *defaultobj = Py_None;
 
-    if (!PyArg_UnpackTuple(args, "setdefault", 1, 2, &key, &defaultobj))
+    val = PyDict_SetDefault((PyObject *)self, key, defaultobj);
-        return NULL;
-
-    val = PyDict_SetDefault((PyObject *)mp, key, defaultobj);
     Py_XINCREF(val);
     return val;
 }
@@ -3072,12 +3085,6 @@ PyDoc_STRVAR(getitem__doc__, "x.__getitem__(y) <==> x[y]");
 PyDoc_STRVAR(sizeof__doc__,
 "D.__sizeof__() -> size of D in memory, in bytes");
 
-PyDoc_STRVAR(get__doc__,
-"D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None.");
-
-PyDoc_STRVAR(setdefault_doc__,
-"D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D");
-
 PyDoc_STRVAR(pop__doc__,
 "D.pop(k[,d]) -> v, remove specified key and return the corresponding value.\n\
 If key is not found, d is returned if given, otherwise KeyError is raised");
@@ -3116,10 +3123,8 @@ static PyMethodDef mapp_methods[] = {
      getitem__doc__},
     {"__sizeof__",      (PyCFunction)dict_sizeof,       METH_NOARGS,
      sizeof__doc__},
-    {"get",         (PyCFunction)dict_get,          METH_VARARGS,
+    DICT_GET_METHODDEF
-     get__doc__},
+    DICT_SETDEFAULT_METHODDEF
-    {"setdefault",  (PyCFunction)dict_setdefault,   METH_VARARGS,
-     setdefault_doc__},
     {"pop",         (PyCFunction)dict_pop,          METH_VARARGS,
      pop__doc__},
     {"popitem",         (PyCFunction)dict_popitem,      METH_NOARGS,