Simplify and optimize calls, using vectorcall on Python 3.8 (GH-2999)

* Do not use unsafe _PyMethodDef_RawFastCallKeywords
* Simplify and optimize calls, using vectorcall on Python 3.8

Cython/Compiler/ExprNodes.py

@@ -6039,8 +6039,6 @@ class PyMethodCallNode(SimpleCallNode):
 
         self_arg = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
         code.putln("%s = NULL;" % self_arg)
-        arg_offset_cname = None
-        if len(args) > 1:
         arg_offset_cname = code.funcstate.allocate_temp(PyrexTypes.c_int_type, manage_ref=False)
         code.putln("%s = 0;" % arg_offset_cname)
 
@@ -6075,122 +6073,41 @@ class PyMethodCallNode(SimpleCallNode):
         code.put_incref("function", py_object_type)
         # free method object as early to possible to enable reuse from CPython's freelist
         code.put_decref_set(function, "function")
-        if len(args) > 1:
         code.putln("%s = 1;" % arg_offset_cname)
         code.putln("}")
         code.putln("}")
 
-        if not args:
-            # fastest special case: try to avoid tuple creation
+        # actually call the function
         code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyObjectCallNoArg", "ObjectHandling.c"))
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyObjectCallOneArg", "ObjectHandling.c"))
-            code.putln(
-                "%s = (%s) ? __Pyx_PyObject_CallOneArg(%s, %s) : __Pyx_PyObject_CallNoArg(%s);" % (
-                    self.result(), self_arg,
-                    function, self_arg,
-                    function))
-            code.put_xdecref_clear(self_arg, py_object_type)
-            code.funcstate.release_temp(self_arg)
-            code.putln(code.error_goto_if_null(self.result(), self.pos))
-            code.put_gotref(self.py_result())
-        elif len(args) == 1:
-            # fastest special case: try to avoid tuple creation
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyObjectCall2Args", "ObjectHandling.c"))
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyObjectCallOneArg", "ObjectHandling.c"))
-            arg = args[0]
-            code.putln(
-                "%s = (%s) ? __Pyx_PyObject_Call2Args(%s, %s, %s) : __Pyx_PyObject_CallOneArg(%s, %s);" % (
-                    self.result(), self_arg,
-                    function, self_arg, arg.py_result(),
-                    function, arg.py_result()))
-            code.put_xdecref_clear(self_arg, py_object_type)
-            code.funcstate.release_temp(self_arg)
-            arg.generate_disposal_code(code)
-            arg.free_temps(code)
-            code.putln(code.error_goto_if_null(self.result(), self.pos))
-            code.put_gotref(self.py_result())
-        else:
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyFunctionFastCall", "ObjectHandling.c"))
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyCFunctionFastCall", "ObjectHandling.c"))
-            for test_func, call_prefix in [('PyFunction_Check', 'Py'), ('__Pyx_PyFastCFunction_Check', 'PyC')]:
-                code.putln("#if CYTHON_FAST_%sCALL" % call_prefix.upper())
-                code.putln("if (%s(%s)) {" % (test_func, function))
-                code.putln("PyObject *%s[%d] = {%s, %s};" % (
-                    Naming.quick_temp_cname,
+            UtilityCode.load_cached("PyObjectFastCall", "ObjectHandling.c"))
+
+        code.putln("{")
+        code.putln("PyObject *__pyx_callargs[%d] = {%s, %s};" % (
             len(args)+1,
             self_arg,
             ', '.join(arg.py_result() for arg in args)))
-                code.putln("%s = __Pyx_%sFunction_FastCall(%s, %s+1-%s, %d+%s); %s" % (
+        code.putln("%s = __Pyx_PyObject_FastCall(%s, __pyx_callargs+1-%s, %d+%s);" % (
             self.result(),
-                    call_prefix,
             function,
-                    Naming.quick_temp_cname,
             arg_offset_cname,
             len(args),
-                    arg_offset_cname,
-                    code.error_goto_if_null(self.result(), self.pos)))
-                code.put_xdecref_clear(self_arg, py_object_type)
-                code.put_gotref(self.py_result())
-                for arg in args:
-                    arg.generate_disposal_code(code)
-                code.putln("} else")
-                code.putln("#endif")
+            arg_offset_cname))
 
-            code.putln("{")
-            args_tuple = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
-            code.putln("%s = PyTuple_New(%d+%s); %s" % (
-                args_tuple, len(args), arg_offset_cname,
-                code.error_goto_if_null(args_tuple, self.pos)))
-            code.put_gotref(args_tuple)
-
-            if len(args) > 1:
-                code.putln("if (%s) {" % self_arg)
-            code.putln("__Pyx_GIVEREF(%s); PyTuple_SET_ITEM(%s, 0, %s); %s = NULL;" % (
-                self_arg, args_tuple, self_arg, self_arg))  # stealing owned ref in this case
+        code.put_xdecref_clear(self_arg, py_object_type)
         code.funcstate.release_temp(self_arg)
-            if len(args) > 1:
-                code.putln("}")
-
-            for i, arg in enumerate(args):
-                arg.make_owned_reference(code)
-                code.put_giveref(arg.py_result())
-                code.putln("PyTuple_SET_ITEM(%s, %d+%s, %s);" % (
-                    args_tuple, i, arg_offset_cname, arg.py_result()))
-            if len(args) > 1:
-                code.funcstate.release_temp(arg_offset_cname)
-
         for arg in args:
-                arg.generate_post_assignment_code(code)
+            arg.generate_disposal_code(code)
             arg.free_temps(code)
-
-            code.globalstate.use_utility_code(
-                UtilityCode.load_cached("PyObjectCall", "ObjectHandling.c"))
-            code.putln(
-                "%s = __Pyx_PyObject_Call(%s, %s, NULL); %s" % (
-                    self.result(),
-                    function, args_tuple,
-                    code.error_goto_if_null(self.result(), self.pos)))
+        code.putln(code.error_goto_if_null(self.result(), self.pos))
         code.put_gotref(self.py_result())
 
-            code.put_decref_clear(args_tuple, py_object_type)
-            code.funcstate.release_temp(args_tuple)
-
-            if len(args) == 1:
-                code.putln("}")
-            code.putln("}")  # !CYTHON_FAST_PYCALL
-
         if reuse_function_temp:
             self.function.generate_disposal_code(code)
             self.function.free_temps(code)
         else:
             code.put_decref_clear(function, py_object_type)
             code.funcstate.release_temp(function)
+        code.putln("}")
 
 
 class InlinedDefNodeCallNode(CallNode):

Cython/Utility/Coroutine.c

@@ -194,14 +194,6 @@ static PyObject *__Pyx__Coroutine_GetAwaitableIter(PyObject *obj) {
         PyObject *method = NULL;
         int is_method = __Pyx_PyObject_GetMethod(obj, PYIDENT("__await__"), &method);
         if (likely(is_method)) {
-#if PY_VERSION_HEX >= 0x030700A1 && CYTHON_UNPACK_METHODS && CYTHON_FAST_PYCCALL
-            if (Py_TYPE(method) == &PyMethodDescr_Type) {
-                PyMethodDescrObject *descr = (PyMethodDescrObject *)method;
-                res = _PyMethodDef_RawFastCallKeywords(descr->d_method, obj, NULL, 0, NULL);
-                if (unlikely(!res))
-                    res = _Py_CheckFunctionResult(obj, res, NULL);
-            } else
-#endif
             res = __Pyx_PyObject_CallOneArg(method, obj);
         } else if (likely(method)) {
             res = __Pyx_PyObject_CallNoArg(method);

Cython/Utility/ModuleSetupCode.c

@@ -198,6 +198,10 @@
 #define CYTHON_FAST_PYCCALL  (CYTHON_FAST_PYCALL && PY_VERSION_HEX >= 0x030600B1)
 #endif
 
+#if !defined(CYTHON_VECTORCALL)
+#define CYTHON_VECTORCALL  (CYTHON_FAST_PYCCALL && PY_VERSION_HEX >= 0x030800B1)
+#endif
+
 #if CYTHON_USE_PYLONG_INTERNALS
   #include "longintrepr.h"
   /* These short defines can easily conflict with other code */
@@ -444,12 +448,6 @@ class __Pyx_FakeReference {
   #define __Pyx_PyCFunctionFast _PyCFunctionFast
   #define __Pyx_PyCFunctionFastWithKeywords _PyCFunctionFastWithKeywords
 #endif
-#if CYTHON_FAST_PYCCALL
-#define __Pyx_PyFastCFunction_Check(func) \
-    ((PyCFunction_Check(func) && (METH_FASTCALL == (PyCFunction_GET_FLAGS(func) & ~(METH_CLASS | METH_STATIC | METH_COEXIST | METH_KEYWORDS | METH_STACKLESS)))))
-#else
-#define __Pyx_PyFastCFunction_Check(func) 0
-#endif
 
 #if CYTHON_COMPILING_IN_PYPY && !defined(PyObject_Malloc)
   #define PyObject_Malloc(s)   PyMem_Malloc(s)

tests/run/iterdict.pyx

@@ -555,3 +555,19 @@ def for_in_iteritems_of_expression(*args, **kwargs):
     for k, v in dict(*args, **kwargs).iteritems():
         result.append((k, v))
     return result
+
+
+cdef class NotADict:
+    """
+    >>> NotADict().listvalues()  # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+    ...
+    TypeError: descriptor 'values' for 'mappingproxy' objects doesn't apply to a 'iterdict.NotADict' object
+    """
+    cdef long v
+    def __cinit__(self):
+        self.v = 1
+    itervalues = type(object.__dict__).values
+
+    def listvalues(self):
+        return [v for v in self.itervalues()]