bpo-37017: PyObject_CallMethodObjArgs uses LOAD_METHOD optimization (GH-13516)
Update PyObject_CallMethodObjArgs and _PyObject_CallMethodIdObjArgs
to use _PyObject_GetMethod to avoid creating a bound method object
in many cases.
On a microbenchmark of PyObject_CallMethodObjArgs calling a method on
an interpreted Python class, this optimization resulted in a 1.7x
speedup.
diff --git a/Objects/call.c b/Objects/call.c
index cb9ccd9..b608492 100644
--- a/Objects/call.c
+++ b/Objects/call.c
@@ -1159,7 +1159,7 @@
/* --- Call with "..." arguments ---------------------------------- */
static PyObject *
-object_vacall(PyObject *callable, va_list vargs)
+object_vacall(PyObject *base, PyObject *callable, va_list vargs)
{
PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];
PyObject **stack;
@@ -1174,7 +1174,7 @@
/* Count the number of arguments */
va_copy(countva, vargs);
- nargs = 0;
+ nargs = base ? 1 : 0;
while (1) {
PyObject *arg = va_arg(countva, PyObject *);
if (arg == NULL) {
@@ -1196,7 +1196,12 @@
}
}
- for (i = 0; i < nargs; ++i) {
+ i = 0;
+ if (base) {
+ stack[i++] = base;
+ }
+
+ for (; i < nargs; ++i) {
stack[i] = va_arg(vargs, PyObject *);
}
@@ -1210,23 +1215,26 @@
}
-PyObject *
-PyObject_CallMethodObjArgs(PyObject *callable, PyObject *name, ...)
-{
- va_list vargs;
- PyObject *result;
+/* Private API for the LOAD_METHOD opcode. */
+extern int _PyObject_GetMethod(PyObject *, PyObject *, PyObject **);
- if (callable == NULL || name == NULL) {
+PyObject *
+PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)
+{
+ if (obj == NULL || name == NULL) {
return null_error();
}
- callable = PyObject_GetAttr(callable, name);
+ PyObject *callable = NULL;
+ int is_method = _PyObject_GetMethod(obj, name, &callable);
if (callable == NULL) {
return NULL;
}
+ obj = is_method ? obj : NULL;
+ va_list vargs;
va_start(vargs, name);
- result = object_vacall(callable, vargs);
+ PyObject *result = object_vacall(obj, callable, vargs);
va_end(vargs);
Py_DECREF(callable);
@@ -1238,20 +1246,25 @@
_PyObject_CallMethodIdObjArgs(PyObject *obj,
struct _Py_Identifier *name, ...)
{
- va_list vargs;
- PyObject *callable, *result;
-
if (obj == NULL || name == NULL) {
return null_error();
}
- callable = _PyObject_GetAttrId(obj, name);
- if (callable == NULL) {
+ PyObject *oname = _PyUnicode_FromId(name); /* borrowed */
+ if (!oname) {
return NULL;
}
+ PyObject *callable = NULL;
+ int is_method = _PyObject_GetMethod(obj, oname, &callable);
+ if (callable == NULL) {
+ return NULL;
+ }
+ obj = is_method ? obj : NULL;
+
+ va_list vargs;
va_start(vargs, name);
- result = object_vacall(callable, vargs);
+ PyObject *result = object_vacall(obj, callable, vargs);
va_end(vargs);
Py_DECREF(callable);
@@ -1266,7 +1279,7 @@
PyObject *result;
va_start(vargs, callable);
- result = object_vacall(callable, vargs);
+ result = object_vacall(NULL, callable, vargs);
va_end(vargs);
return result;