bpo-47127: Specialize calls for fastcall c functions with keywords

Lib/opcode.py

@@ -294,6 +294,7 @@ def jabs_op(name, op, entries=0):
         "PRECALL_BOUND_METHOD",
         "PRECALL_BUILTIN_CLASS",
         "PRECALL_BUILTIN_FAST_WITH_KEYWORDS",
+        "PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS",
         "PRECALL_NO_KW_BUILTIN_FAST",
         "PRECALL_NO_KW_BUILTIN_O",
         "PRECALL_NO_KW_ISINSTANCE",

Misc/NEWS.d/next/Core and Builtins/2022-03-26-12-21-53.bpo-47127.Mh86RB.rst

@@ -0,0 +1 @@
+Speed up calls to c functions with keyword arguments by 25% with specialization. Patch by Kumar Aditya.

Python/ceval.c

@@ -5090,6 +5090,38 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
             DISPATCH();
         }
 
+        TARGET(PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS) {
+            int is_meth = is_method(stack_pointer, oparg);
+            int total_args = oparg + is_meth;
+            PyObject *callable = PEEK(total_args + 1);
+            DEOPT_IF(!Py_IS_TYPE(callable, &PyMethodDescr_Type), PRECALL);
+            PyMethodDef *meth = ((PyMethodDescrObject *)callable)->d_method;
+            DEOPT_IF(meth->ml_flags != (METH_FASTCALL|METH_KEYWORDS), PRECALL);
+            STAT_INC(PRECALL, hit);
+            SKIP_CALL();
+            int nargs = total_args-1;
+            STACK_SHRINK(nargs);
+            _PyCFunctionFastWithKeywords cfunc = (_PyCFunctionFastWithKeywords)(void(*)(void))meth->ml_meth;
+            PyObject *self = TOP();
+            PyObject *res = cfunc(self, stack_pointer, nargs - KWNAMES_LEN(), call_shape.kwnames);
+            assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
+            call_shape.kwnames = NULL;
+
+            /* Free the arguments. */
+            for (int i = 0; i < nargs; i++) {
+                Py_DECREF(stack_pointer[i]);
+            }
+            Py_DECREF(self);
+            STACK_SHRINK(2-is_meth);
+            SET_TOP(res);
+            Py_DECREF(callable);
+            if (res == NULL) {
+                goto error;
+            }
+            CHECK_EVAL_BREAKER();
+            DISPATCH();
+        }
+
         TARGET(PRECALL_NO_KW_METHOD_DESCRIPTOR_NOARGS) {
             assert(call_shape.kwnames == NULL);
             assert(oparg == 0 || oparg == 1);

Python/specialize.c

@@ -1446,6 +1446,10 @@ specialize_method_descriptor(PyMethodDescrObject *descr, _Py_CODEUNIT *instr,
             _Py_SET_OPCODE(*instr, PRECALL_NO_KW_METHOD_DESCRIPTOR_FAST);
             return 0;
         }
+        case METH_FASTCALL|METH_KEYWORDS: {
+            _Py_SET_OPCODE(*instr, PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS);
+            return 0;
+        }
     }
     SPECIALIZATION_FAIL(PRECALL, builtin_call_fail_kind(descr->d_method->ml_flags));
     return -1;