bpo-44850: Improve the performance of methodcaller. by anntzer · Pull Request #27782 · python/cpython

diff --git i/Modules/_operator.c w/Modules/_operator.c
index de4613a6a8..cee6df24fe 100644
--- i/Modules/_operator.c
+++ w/Modules/_operator.c
@@ -1,5 +1,6 @@
 #include "Python.h"
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
+#include "structmember.h"
 #include "clinic/_operator.c.h"
 
 typedef struct {
@@ -1480,8 +1481,44 @@ typedef struct {
     PyObject *kwds;
     PyObject **vectorcall_args;  /* Borrowed references */
     PyObject *vectorcall_kwnames;
+    vectorcallfunc vectorcall;
 } methodcallerobject;
 
+static PyObject *
+methodcaller_vectorcall(
+        methodcallerobject *mc, PyObject *const *args, size_t nargsf, PyObject* kwnames)
+{
+    printf("vectorcall\n");
+    if (!_PyArg_NoKwnames("methodcaller", kwnames))
+        return NULL;
+    if (PyVectorcall_NARGS(nargsf) != 1) {
+        PyErr_Format(
+                PyExc_TypeError,
+                "methodcaller expected 1 argument, got %zd",
+                PyVectorcall_NARGS(nargsf));
+        return NULL;
+    }
+    mc->vectorcall_args[0] = args[0];
+    return PyObject_VectorcallMethod(
+            mc->name, mc->vectorcall_args,
+            (1 + PyTuple_GET_SIZE(mc->args)) | PY_VECTORCALL_ARGUMENTS_OFFSET,
+            mc->vectorcall_kwnames);
+}
+
+static PyObject *
+methodcaller_call(methodcallerobject *mc, PyObject *args, PyObject *kw)
+{
+    if (!_PyArg_NoKeywords("methodcaller", kw))
+        return NULL;
+    if (!_PyArg_CheckPositional("methodcaller", PyTuple_GET_SIZE(args), 1, 1))
+        return NULL;
+    mc->vectorcall_args[0] = PyTuple_GET_ITEM(args, 0);
+    return PyObject_VectorcallMethod(
+            mc->name, mc->vectorcall_args,
+            (1 + PyTuple_GET_SIZE(mc->args)) | PY_VECTORCALL_ARGUMENTS_OFFSET,
+            mc->vectorcall_kwnames);
+}
+
 /* AC 3.5: variable number of arguments, not currently support by AC */
 static PyObject *
 methodcaller_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
@@ -1548,6 +1585,7 @@ methodcaller_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     else {
         mc->vectorcall_kwnames = NULL;
     }
+    mc->vectorcall = (vectorcallfunc)methodcaller_vectorcall;
 
     PyObject_GC_Track(mc);
     return (PyObject *)mc;
@@ -1584,20 +1622,6 @@ methodcaller_traverse(methodcallerobject *mc, visitproc visit, void *arg)
     return 0;
 }
 
-static PyObject *
-methodcaller_call(methodcallerobject *mc, PyObject *args, PyObject *kw)
-{
-    if (!_PyArg_NoKeywords("methodcaller", kw))
-        return NULL;
-    if (!_PyArg_CheckPositional("methodcaller", PyTuple_GET_SIZE(args), 1, 1))
-        return NULL;
-    mc->vectorcall_args[0] = PyTuple_GET_ITEM(args, 0);
-    return PyObject_VectorcallMethod(
-            mc->name, mc->vectorcall_args,
-            (1 + PyTuple_GET_SIZE(mc->args)) | PY_VECTORCALL_ARGUMENTS_OFFSET,
-            mc->vectorcall_kwnames);
-}
-
 static PyObject *
 methodcaller_repr(methodcallerobject *mc)
 {
@@ -1722,6 +1746,12 @@ static PyMethodDef methodcaller_methods[] = {
      reduce_doc},
     {NULL}
 };
+
+static PyMemberDef methodcaller_members[] = {
+    {"__vectorcalloffset__", T_PYSSIZET, offsetof(methodcallerobject, vectorcall), READONLY},
+    {NULL}
+};
+
 PyDoc_STRVAR(methodcaller_doc,
 "methodcaller(name, ...) --> methodcaller object\n\
 \n\
@@ -1737,6 +1767,7 @@ static PyType_Slot methodcaller_type_slots[] = {
     {Py_tp_traverse, methodcaller_traverse},
     {Py_tp_clear, methodcaller_clear},
     {Py_tp_methods, methodcaller_methods},
+    {Py_tp_members, methodcaller_members},
     {Py_tp_new, methodcaller_new},
     {Py_tp_getattro, PyObject_GenericGetAttr},
     {Py_tp_repr, methodcaller_repr},