Backed out changeset f23fa1f7b68f

Sorry, I didn't want to push this change before the review :-( I was pushing a
change into the 2.7 branch.

Include/eval.h

@@ -10,24 +10,14 @@ extern "C" {
 PyAPI_FUNC(PyObject *) PyEval_EvalCode(PyObject *, PyObject *, PyObject *);
 
 PyAPI_FUNC(PyObject *) PyEval_EvalCodeEx(PyObject *co,
-                                         PyObject *globals,
-                                         PyObject *locals,
-                                         PyObject **args, int argc,
-                                         PyObject **kwds, int kwdc,
-                                         PyObject **defs, int defc,
-                                         PyObject *kwdefs, PyObject *closure);
+					PyObject *globals,
+					PyObject *locals,
+					PyObject **args, int argc,
+					PyObject **kwds, int kwdc,
+					PyObject **defs, int defc,
+					PyObject *kwdefs, PyObject *closure);
 
 #ifndef Py_LIMITED_API
-PyAPI_FUNC(PyObject *) _PyEval_EvalCodeWithName(
-    PyObject *co,
-    PyObject *globals, PyObject *locals,
-    PyObject **args, Py_ssize_t argcount,
-    PyObject **kwnames, PyObject **kwargs,
-    Py_ssize_t kwcount, int kwstep,
-    PyObject **defs, Py_ssize_t defcount,
-    PyObject *kwdefs, PyObject *closure,
-    PyObject *name, PyObject *qualname);
-
 PyAPI_FUNC(PyObject *) _PyEval_CallTracing(PyObject *func, PyObject *args);
 #endif
 

Makefile.pre.in

@@ -409,7 +409,6 @@ OBJECT_OBJS=	\
 		Objects/bytes_methods.o \
 		Objects/bytearrayobject.o \
 		Objects/bytesobject.o \
-		Objects/call.o \
 		Objects/cellobject.o \
 		Objects/classobject.o \
 		Objects/codeobject.o \

Objects/methodobject.c

@@ -77,6 +77,329 @@ PyCFunction_GetFlags(PyObject *op)
     return PyCFunction_GET_FLAGS(op);
 }
 
+static PyObject *
+cfunction_call_varargs(PyObject *func, PyObject *args, PyObject *kwargs)
+{
+    assert(!PyErr_Occurred());
+
+    PyCFunction meth = PyCFunction_GET_FUNCTION(func);
+    PyObject *self = PyCFunction_GET_SELF(func);
+    PyObject *result;
+
+    if (PyCFunction_GET_FLAGS(func) & METH_KEYWORDS) {
+        if (Py_EnterRecursiveCall(" while calling a Python object")) {
+            return NULL;
+        }
+
+        result = (*(PyCFunctionWithKeywords)meth)(self, args, kwargs);
+
+        Py_LeaveRecursiveCall();
+    }
+    else {
+        if (kwargs != NULL && PyDict_Size(kwargs) != 0) {
+            PyErr_Format(PyExc_TypeError, "%.200s() takes no keyword arguments",
+                         ((PyCFunctionObject*)func)->m_ml->ml_name);
+            return NULL;
+        }
+
+        if (Py_EnterRecursiveCall(" while calling a Python object")) {
+            return NULL;
+        }
+
+        result = (*meth)(self, args);
+
+        Py_LeaveRecursiveCall();
+    }
+
+    return _Py_CheckFunctionResult(func, result, NULL);
+}
+
+
+PyObject *
+PyCFunction_Call(PyObject *func, PyObject *args, PyObject *kwargs)
+{
+    /* first try METH_VARARGS to pass directly args tuple unchanged.
+       _PyMethodDef_RawFastCallDict() creates a new temporary tuple
+       for METH_VARARGS. */
+    if (PyCFunction_GET_FLAGS(func) & METH_VARARGS) {
+        return cfunction_call_varargs(func, args, kwargs);
+    }
+    else {
+        return _PyCFunction_FastCallDict(func,
+                                         &PyTuple_GET_ITEM(args, 0),
+                                         PyTuple_GET_SIZE(args),
+                                         kwargs);
+    }
+}
+
+PyObject *
+_PyMethodDef_RawFastCallDict(PyMethodDef *method, PyObject *self, PyObject **args,
+                             Py_ssize_t nargs, PyObject *kwargs)
+{
+    /* _PyMethodDef_RawFastCallDict() must not be called with an exception set,
+       because it can clear it (directly or indirectly) and so the
+       caller loses its exception */
+    assert(!PyErr_Occurred());
+
+    assert(method != NULL);
+    assert(nargs >= 0);
+    assert(nargs == 0 || args != NULL);
+    assert(kwargs == NULL || PyDict_Check(kwargs));
+
+    PyCFunction meth = method->ml_meth;
+    int flags = method->ml_flags & ~(METH_CLASS | METH_STATIC | METH_COEXIST);
+    PyObject *result = NULL;
+
+    if (Py_EnterRecursiveCall(" while calling a Python object")) {
+        return NULL;
+    }
+
+    switch (flags)
+    {
+    case METH_NOARGS:
+        if (nargs != 0) {
+            PyErr_Format(PyExc_TypeError,
+                "%.200s() takes no arguments (%zd given)",
+                method->ml_name, nargs);
+            goto exit;
+        }
+
+        if (kwargs != NULL && PyDict_GET_SIZE(kwargs) != 0) {
+            goto no_keyword_error;
+        }
+
+        result = (*meth) (self, NULL);
+        break;
+
+    case METH_O:
+        if (nargs != 1) {
+            PyErr_Format(PyExc_TypeError,
+                "%.200s() takes exactly one argument (%zd given)",
+                method->ml_name, nargs);
+            goto exit;
+        }
+
+        if (kwargs != NULL && PyDict_GET_SIZE(kwargs) != 0) {
+            goto no_keyword_error;
+        }
+
+        result = (*meth) (self, args[0]);
+        break;
+
+    case METH_VARARGS:
+        if (!(flags & METH_KEYWORDS)
+                && kwargs != NULL && PyDict_GET_SIZE(kwargs) != 0) {
+            goto no_keyword_error;
+        }
+        /* fall through next case */
+
+    case METH_VARARGS | METH_KEYWORDS:
+    {
+        /* Slow-path: create a temporary tuple for positional arguments */
+        PyObject *argstuple = _PyStack_AsTuple(args, nargs);
+        if (argstuple == NULL) {
+            goto exit;
+        }
+
+        if (flags & METH_KEYWORDS) {
+            result = (*(PyCFunctionWithKeywords)meth) (self, argstuple, kwargs);
+        }
+        else {
+            result = (*meth) (self, argstuple);
+        }
+        Py_DECREF(argstuple);
+        break;
+    }
+
+    case METH_FASTCALL:
+    {
+        PyObject **stack;
+        PyObject *kwnames;
+        _PyCFunctionFast fastmeth = (_PyCFunctionFast)meth;
+
+        if (_PyStack_UnpackDict(args, nargs, kwargs, &stack, &kwnames) < 0) {
+            goto exit;
+        }
+
+        result = (*fastmeth) (self, stack, nargs, kwnames);
+        if (stack != args) {
+            PyMem_Free(stack);
+        }
+        Py_XDECREF(kwnames);
+        break;
+    }
+
+    default:
+        PyErr_SetString(PyExc_SystemError,
+                        "Bad call flags in _PyMethodDef_RawFastCallDict. "
+                        "METH_OLDARGS is no longer supported!");
+        goto exit;
+    }
+
+    goto exit;
+
+no_keyword_error:
+    PyErr_Format(PyExc_TypeError,
+                 "%.200s() takes no keyword arguments",
+                 method->ml_name, nargs);
+
+exit:
+    Py_LeaveRecursiveCall();
+    return result;
+}
+
+PyObject *
+_PyCFunction_FastCallDict(PyObject *func, PyObject **args, Py_ssize_t nargs,
+                          PyObject *kwargs)
+{
+    PyObject *result;
+
+    assert(func != NULL);
+    assert(PyCFunction_Check(func));
+
+    result = _PyMethodDef_RawFastCallDict(((PyCFunctionObject*)func)->m_ml,
+                                          PyCFunction_GET_SELF(func),
+                                          args, nargs, kwargs);
+    result = _Py_CheckFunctionResult(func, result, NULL);
+    return result;
+}
+
+PyObject *
+_PyMethodDef_RawFastCallKeywords(PyMethodDef *method, PyObject *self, PyObject **args,
+                                 Py_ssize_t nargs, PyObject *kwnames)
+{
+    /* _PyMethodDef_RawFastCallKeywords() must not be called with an exception set,
+       because it can clear it (directly or indirectly) and so the
+       caller loses its exception */
+    assert(!PyErr_Occurred());
+
+    assert(method != NULL);
+    assert(nargs >= 0);
+    assert(kwnames == NULL || PyTuple_CheckExact(kwnames));
+    /* kwnames must only contains str strings, no subclass, and all keys must
+       be unique */
+
+    PyCFunction meth = method->ml_meth;
+    int flags = method->ml_flags & ~(METH_CLASS | METH_STATIC | METH_COEXIST);
+    Py_ssize_t nkwargs = kwnames == NULL ? 0 : PyTuple_Size(kwnames);
+    PyObject *result = NULL;
+
+    if (Py_EnterRecursiveCall(" while calling a Python object")) {
+        return NULL;
+    }
+
+    switch (flags)
+    {
+    case METH_NOARGS:
+        if (nargs != 0) {
+            PyErr_Format(PyExc_TypeError,
+                "%.200s() takes no arguments (%zd given)",
+                method->ml_name, nargs);
+            goto exit;
+        }
+
+        if (nkwargs) {
+            goto no_keyword_error;
+        }
+
+        result = (*meth) (self, NULL);
+        break;
+
+    case METH_O:
+        if (nargs != 1) {
+            PyErr_Format(PyExc_TypeError,
+                "%.200s() takes exactly one argument (%zd given)",
+                method->ml_name, nargs);
+            goto exit;
+        }
+
+        if (nkwargs) {
+            goto no_keyword_error;
+        }
+
+        result = (*meth) (self, args[0]);
+        break;
+
+    case METH_FASTCALL:
+        /* Fast-path: avoid temporary dict to pass keyword arguments */
+        result = ((_PyCFunctionFast)meth) (self, args, nargs, kwnames);
+        break;
+
+    case METH_VARARGS:
+    case METH_VARARGS | METH_KEYWORDS:
+    {
+        /* Slow-path: create a temporary tuple for positional arguments
+           and a temporary dict for keyword arguments */
+        PyObject *argtuple;
+
+        if (!(flags & METH_KEYWORDS) && nkwargs) {
+            goto no_keyword_error;
+        }
+
+        argtuple = _PyStack_AsTuple(args, nargs);
+        if (argtuple == NULL) {
+            goto exit;
+        }
+
+        if (flags & METH_KEYWORDS) {
+            PyObject *kwdict;
+
+            if (nkwargs > 0) {
+                kwdict = _PyStack_AsDict(args + nargs, kwnames);
+                if (kwdict == NULL) {
+                    Py_DECREF(argtuple);
+                    goto exit;
+                }
+            }
+            else {
+                kwdict = NULL;
+            }
+
+            result = (*(PyCFunctionWithKeywords)meth) (self, argtuple, kwdict);
+            Py_XDECREF(kwdict);
+        }
+        else {
+            result = (*meth) (self, argtuple);
+        }
+        Py_DECREF(argtuple);
+        break;
+    }
+
+    default:
+        PyErr_SetString(PyExc_SystemError,
+                        "Bad call flags in _PyCFunction_FastCallKeywords. "
+                        "METH_OLDARGS is no longer supported!");
+        goto exit;
+    }
+
+    goto exit;
+
+no_keyword_error:
+    PyErr_Format(PyExc_TypeError,
+                 "%.200s() takes no keyword arguments",
+                 method->ml_name);
+
+exit:
+    Py_LeaveRecursiveCall();
+    return result;
+}
+
+PyObject *
+_PyCFunction_FastCallKeywords(PyObject *func, PyObject **args,
+                              Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *result;
+
+    assert(func != NULL);
+    assert(PyCFunction_Check(func));
+
+    result = _PyMethodDef_RawFastCallKeywords(((PyCFunctionObject*)func)->m_ml,
+                                              PyCFunction_GET_SELF(func),
+                                              args, nargs, kwnames);
+    result = _Py_CheckFunctionResult(func, result, NULL);
+    return result;
+}
+
 /* Methods (the standard built-in methods, that is) */
 
 static void

PCbuild/pythoncore.vcxproj

@@ -294,10 +294,9 @@
     <ClCompile Include="..\Objects\abstract.c" />
     <ClCompile Include="..\Objects\accu.c" />
     <ClCompile Include="..\Objects\boolobject.c" />
-    <ClCompile Include="..\Objects\bytearrayobject.c" />
     <ClCompile Include="..\Objects\bytes_methods.c" />
+    <ClCompile Include="..\Objects\bytearrayobject.c" />
     <ClCompile Include="..\Objects\bytesobject.c" />
-    <ClCompile Include="..\Objects\call.c" />
     <ClCompile Include="..\Objects\capsule.c" />
     <ClCompile Include="..\Objects\cellobject.c" />
     <ClCompile Include="..\Objects\classobject.c" />

Python/ceval.c

@@ -37,6 +37,7 @@ typedef PyObject *(*callproc)(PyObject *, PyObject *, PyObject *);
 
 /* Forward declarations */
 Py_LOCAL_INLINE(PyObject *) call_function(PyObject ***, Py_ssize_t, PyObject *);
+static PyObject * fast_function(PyObject *, PyObject **, Py_ssize_t, PyObject *);
 static PyObject * do_call_core(PyObject *, PyObject *, PyObject *);
 
 #ifdef LLTRACE
@@ -3894,7 +3895,7 @@ too_many_positional(PyCodeObject *co, Py_ssize_t given, Py_ssize_t defcount,
    PyEval_EvalFrame() and PyEval_EvalCodeEx() you will need to adjust
    the test in the if statements in Misc/gdbinit (pystack and pystackv). */
 
-PyObject *
+static PyObject *
 _PyEval_EvalCodeWithName(PyObject *_co, PyObject *globals, PyObject *locals,
            PyObject **args, Py_ssize_t argcount,
            PyObject **kwnames, PyObject **kwargs,
@@ -4731,6 +4732,39 @@ PyEval_MergeCompilerFlags(PyCompilerFlags *cf)
 }
 
 
+/* External interface to call any callable object.
+   The arg must be a tuple or NULL.  The kw must be a dict or NULL. */
+
+PyObject *
+PyEval_CallObjectWithKeywords(PyObject *callable,
+                              PyObject *args, PyObject *kwargs)
+{
+#ifdef Py_DEBUG
+    /* PyEval_CallObjectWithKeywords() must not be called with an exception
+       set. It raises a new exception if parameters are invalid or if
+       PyTuple_New() fails, and so the original exception is lost. */
+    assert(!PyErr_Occurred());
+#endif
+
+    if (args == NULL) {
+        return _PyObject_FastCallDict(callable, NULL, 0, kwargs);
+    }
+
+    if (!PyTuple_Check(args)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "argument list must be a tuple");
+        return NULL;
+    }
+
+    if (kwargs != NULL && !PyDict_Check(kwargs)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "keyword list must be a dictionary");
+        return NULL;
+    }
+
+    return PyObject_Call(callable, args, kwargs);
+}
+
 const char *
 PyEval_GetFuncName(PyObject *func)
 {
@@ -4831,7 +4865,7 @@ call_function(PyObject ***pp_stack, Py_ssize_t oparg, PyObject *kwnames)
         }
 
         if (PyFunction_Check(func)) {
-            x = _PyFunction_FastCallKeywords(func, stack, nargs, kwnames);
+            x = fast_function(func, stack, nargs, kwnames);
         }
         else {
             x = _PyObject_FastCallKeywords(func, stack, nargs, kwnames);
@@ -4841,7 +4875,10 @@ call_function(PyObject ***pp_stack, Py_ssize_t oparg, PyObject *kwnames)
 
     assert((x != NULL) ^ (PyErr_Occurred() != NULL));
 
-    /* Clear the stack of the function object. */
+    /* Clear the stack of the function object.  Also removes
+       the arguments in case they weren't consumed already
+       (fast_function() and err_args() leave them on the stack).
+     */
     while ((*pp_stack) > pfunc) {
         w = EXT_POP(*pp_stack);
         Py_DECREF(w);
@@ -4850,6 +4887,205 @@ call_function(PyObject ***pp_stack, Py_ssize_t oparg, PyObject *kwnames)
     return x;
 }
 
+/* The fast_function() function optimize calls for which no argument
+   tuple is necessary; the objects are passed directly from the stack.
+   For the simplest case -- a function that takes only positional
+   arguments and is called with only positional arguments -- it
+   inlines the most primitive frame setup code from
+   PyEval_EvalCodeEx(), which vastly reduces the checks that must be
+   done before evaluating the frame.
+*/
+
+static PyObject* _Py_HOT_FUNCTION
+_PyFunction_FastCall(PyCodeObject *co, PyObject **args, Py_ssize_t nargs,
+                     PyObject *globals)
+{
+    PyFrameObject *f;
+    PyThreadState *tstate = PyThreadState_GET();
+    PyObject **fastlocals;
+    Py_ssize_t i;
+    PyObject *result;
+
+    assert(globals != NULL);
+    /* XXX Perhaps we should create a specialized
+       _PyFrame_New_NoTrack() that doesn't take locals, but does
+       take builtins without sanity checking them.
+       */
+    assert(tstate != NULL);
+    f = _PyFrame_New_NoTrack(tstate, co, globals, NULL);
+    if (f == NULL) {
+        return NULL;
+    }
+
+    fastlocals = f->f_localsplus;
+
+    for (i = 0; i < nargs; i++) {
+        Py_INCREF(*args);
+        fastlocals[i] = *args++;
+    }
+    result = PyEval_EvalFrameEx(f,0);
+
+    if (Py_REFCNT(f) > 1) {
+        Py_DECREF(f);
+        _PyObject_GC_TRACK(f);
+    }
+    else {
+        ++tstate->recursion_depth;
+        Py_DECREF(f);
+        --tstate->recursion_depth;
+    }
+    return result;
+}
+
+static PyObject *
+fast_function(PyObject *func, PyObject **stack,
+              Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyCodeObject *co = (PyCodeObject *)PyFunction_GET_CODE(func);
+    PyObject *globals = PyFunction_GET_GLOBALS(func);
+    PyObject *argdefs = PyFunction_GET_DEFAULTS(func);
+    PyObject *kwdefs, *closure, *name, *qualname;
+    PyObject **d;
+    Py_ssize_t nkwargs = (kwnames == NULL) ? 0 : PyTuple_GET_SIZE(kwnames);
+    Py_ssize_t nd;
+
+    assert(PyFunction_Check(func));
+    assert(nargs >= 0);
+    assert(kwnames == NULL || PyTuple_CheckExact(kwnames));
+    assert((nargs == 0 && nkwargs == 0) || stack != NULL);
+    /* kwnames must only contains str strings, no subclass, and all keys must
+       be unique */
+
+    if (co->co_kwonlyargcount == 0 && nkwargs == 0 &&
+        co->co_flags == (CO_OPTIMIZED | CO_NEWLOCALS | CO_NOFREE))
+    {
+        if (argdefs == NULL && co->co_argcount == nargs) {
+            return _PyFunction_FastCall(co, stack, nargs, globals);
+        }
+        else if (nargs == 0 && argdefs != NULL
+                 && co->co_argcount == Py_SIZE(argdefs)) {
+            /* function called with no arguments, but all parameters have
+               a default value: use default values as arguments .*/
+            stack = &PyTuple_GET_ITEM(argdefs, 0);
+            return _PyFunction_FastCall(co, stack, Py_SIZE(argdefs), globals);
+        }
+    }
+
+    kwdefs = PyFunction_GET_KW_DEFAULTS(func);
+    closure = PyFunction_GET_CLOSURE(func);
+    name = ((PyFunctionObject *)func) -> func_name;
+    qualname = ((PyFunctionObject *)func) -> func_qualname;
+
+    if (argdefs != NULL) {
+        d = &PyTuple_GET_ITEM(argdefs, 0);
+        nd = Py_SIZE(argdefs);
+    }
+    else {
+        d = NULL;
+        nd = 0;
+    }
+    return _PyEval_EvalCodeWithName((PyObject*)co, globals, (PyObject *)NULL,
+                                    stack, nargs,
+                                    nkwargs ? &PyTuple_GET_ITEM(kwnames, 0) : NULL,
+                                    stack + nargs,
+                                    nkwargs, 1,
+                                    d, (int)nd, kwdefs,
+                                    closure, name, qualname);
+}
+
+PyObject *
+_PyFunction_FastCallKeywords(PyObject *func, PyObject **stack,
+                             Py_ssize_t nargs, PyObject *kwnames)
+{
+    return fast_function(func, stack, nargs, kwnames);
+}
+
+PyObject *
+_PyFunction_FastCallDict(PyObject *func, PyObject **args, Py_ssize_t nargs,
+                         PyObject *kwargs)
+{
+    PyCodeObject *co = (PyCodeObject *)PyFunction_GET_CODE(func);
+    PyObject *globals = PyFunction_GET_GLOBALS(func);
+    PyObject *argdefs = PyFunction_GET_DEFAULTS(func);
+    PyObject *kwdefs, *closure, *name, *qualname;
+    PyObject *kwtuple, **k;
+    PyObject **d;
+    Py_ssize_t nd, nk;
+    PyObject *result;
+
+    assert(func != NULL);
+    assert(nargs >= 0);
+    assert(nargs == 0 || args != NULL);
+    assert(kwargs == NULL || PyDict_Check(kwargs));
+
+    if (co->co_kwonlyargcount == 0 &&
+        (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) &&
+        co->co_flags == (CO_OPTIMIZED | CO_NEWLOCALS | CO_NOFREE))
+    {
+        /* Fast paths */
+        if (argdefs == NULL && co->co_argcount == nargs) {
+            return _PyFunction_FastCall(co, args, nargs, globals);
+        }
+        else if (nargs == 0 && argdefs != NULL
+                 && co->co_argcount == Py_SIZE(argdefs)) {
+            /* function called with no arguments, but all parameters have
+               a default value: use default values as arguments .*/
+            args = &PyTuple_GET_ITEM(argdefs, 0);
+            return _PyFunction_FastCall(co, args, Py_SIZE(argdefs), globals);
+        }
+    }
+
+    nk = (kwargs != NULL) ? PyDict_GET_SIZE(kwargs) : 0;
+    if (nk != 0) {
+        Py_ssize_t pos, i;
+
+        /* Issue #29318: Caller and callee functions must not share the
+           dictionary: kwargs must be copied. */
+        kwtuple = PyTuple_New(2 * nk);
+        if (kwtuple == NULL) {
+            return NULL;
+        }
+
+        k = &PyTuple_GET_ITEM(kwtuple, 0);
+        pos = i = 0;
+        while (PyDict_Next(kwargs, &pos, &k[i], &k[i+1])) {
+            /* We must hold strong references because keyword arguments can be
+               indirectly modified while the function is called:
+               see issue #2016 and test_extcall */
+            Py_INCREF(k[i]);
+            Py_INCREF(k[i+1]);
+            i += 2;
+        }
+        nk = i / 2;
+    }
+    else {
+        kwtuple = NULL;
+        k = NULL;
+    }
+
+    kwdefs = PyFunction_GET_KW_DEFAULTS(func);
+    closure = PyFunction_GET_CLOSURE(func);
+    name = ((PyFunctionObject *)func) -> func_name;
+    qualname = ((PyFunctionObject *)func) -> func_qualname;
+
+    if (argdefs != NULL) {
+        d = &PyTuple_GET_ITEM(argdefs, 0);
+        nd = Py_SIZE(argdefs);
+    }
+    else {
+        d = NULL;
+        nd = 0;
+    }
+
+    result = _PyEval_EvalCodeWithName((PyObject*)co, globals, (PyObject *)NULL,
+                                      args, nargs,
+                                      k, k + 1, nk, 2,
+                                      d, nd, kwdefs,
+                                      closure, name, qualname);
+    Py_XDECREF(kwtuple);
+    return result;
+}
+
 static PyObject *
 do_call_core(PyObject *func, PyObject *callargs, PyObject *kwdict)
 {

Python/modsupport.c

@@ -586,6 +586,57 @@ va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len,
 }
 
 
+PyObject *
+PyEval_CallFunction(PyObject *callable, const char *format, ...)
+{
+    va_list vargs;
+    PyObject *args;
+    PyObject *res;
+
+    va_start(vargs, format);
+
+    args = Py_VaBuildValue(format, vargs);
+    va_end(vargs);
+
+    if (args == NULL)
+        return NULL;
+
+    res = PyEval_CallObject(callable, args);
+    Py_DECREF(args);
+
+    return res;
+}
+
+
+PyObject *
+PyEval_CallMethod(PyObject *obj, const char *name, const char *format, ...)
+{
+    va_list vargs;
+    PyObject *meth;
+    PyObject *args;
+    PyObject *res;
+
+    meth = PyObject_GetAttrString(obj, name);
+    if (meth == NULL)
+        return NULL;
+
+    va_start(vargs, format);
+
+    args = Py_VaBuildValue(format, vargs);
+    va_end(vargs);
+
+    if (args == NULL) {
+        Py_DECREF(meth);
+        return NULL;
+    }
+
+    res = PyEval_CallObject(meth, args);
+    Py_DECREF(meth);
+    Py_DECREF(args);
+
+    return res;
+}
+
 int
 PyModule_AddObject(PyObject *m, const char *name, PyObject *o)
 {