Add a new public PyObject_CallNoArgs() function to the C API: call a
callable Python object without any arguments.
It is the most efficient way to call a callback without any argument.
On x86-64, for example, PyObject_CallFunctionObjArgs(func, NULL)
allocates 960 bytes on the stack per call, whereas
PyObject_CallNoArgs(func) only allocates 624 bytes per call.
It is excluded from stable ABI 3.8.
Replace private _PyObject_CallNoArg() with public
PyObject_CallNoArgs() in C extensions: _asyncio, _datetime,
_elementtree, _pickle, _tkinter and readline.
During development of the limited API support for PySide,
we saw an error in a macro that accessed a type field.
This patch fixes the 7 errors in the Python headers.
Macros which were not written as capitals were implemented
as function.
To do the necessary analysis again, a script was included that
parses all headers and looks for "->tp_" in serctions which can
be reached with active limited API.
It is easily possible to call this script as a test.
Error listing:
../../Include/objimpl.h:243
#define PyObject_IS_GC(o) (PyType_IS_GC(Py_TYPE(o)) && \
(Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
Action: commented only
../../Include/objimpl.h:362
#define PyType_SUPPORTS_WEAKREFS(t) ((t)->tp_weaklistoffset > 0)
Action: commented only
../../Include/objimpl.h:364
#define PyObject_GET_WEAKREFS_LISTPTR(o) \
((PyObject **) (((char *) (o)) + Py_TYPE(o)->tp_weaklistoffset))
Action: commented only
../../Include/pyerrors.h:143
#define PyExceptionClass_Name(x) \
((char *)(((PyTypeObject*)(x))->tp_name))
Action: implemented function
../../Include/abstract.h:593
#define PyIter_Check(obj) \
((obj)->ob_type->tp_iternext != NULL && \
(obj)->ob_type->tp_iternext != &_PyObject_NextNotImplemented)
Action: implemented function
../../Include/abstract.h:713
#define PyIndex_Check(obj) \
((obj)->ob_type->tp_as_number != NULL && \
(obj)->ob_type->tp_as_number->nb_index != NULL)
Action: implemented function
../../Include/abstract.h:924
#define PySequence_ITEM(o, i)\
( Py_TYPE(o)->tp_as_sequence->sq_item(o, i) )
Action: commented only
* Add _PyObject_HasFastCall()
* partial_call() now avoids temporary tuple to pass positional
arguments if the callable supports the FASTCALL calling convention
for positional arguments.
* Fix also a performance regression in partial_call() if the callable
doesn't support FASTCALL.
Issue #29507: Optimize slots calling Python methods. For Python methods, get
the unbound Python function and prepend arguments with self, rather than
calling the descriptor which creates a temporary PyMethodObject.
Add a new _PyObject_FastCall_Prepend() function used to call the unbound Python
method with self. It avoids the creation of a temporary tuple to pass
positional arguments.
Avoiding temporary PyMethodObject and avoiding temporary tuple makes Python
slots up to 1.46x faster. Microbenchmark on a __getitem__() method implemented
in Python:
Median +- std dev: 121 ns +- 5 ns -> 82.8 ns +- 1.0 ns: 1.46x faster (-31%)
Co-Authored-by: INADA Naoki <songofacandy@gmail.com>
Issue #29233: Replace the inefficient _PyObject_VaCallFunctionObjArgs() with
_PyObject_FastCall() in call_method() and call_maybe().
Only a few functions call call_method() and call it with a fixed number of
arguments. Avoid the complex and expensive _PyObject_VaCallFunctionObjArgs()
function, replace it with an array allocated on the stack with the exact number
of argumlents.
It reduces the stack consumption, bytes per call, before => after:
test_python_call: 1168 => 1152 (-16 B)
test_python_getitem: 1344 => 1008 (-336 B)
test_python_iterator: 1568 => 1232 (-336 B)
Remove the _PyObject_VaCallFunctionObjArgs() function which became useless.
Rename it to object_vacall() and make it private.
Issue #28838: The documentation is of the Python C API is more complete and
more up to date than this old comment.
Removal suggested by Antoine Pitrou.
Issue #28870: Add a new _PY_FASTCALL_SMALL_STACK constant, size of "small
stacks" allocated on the C stack to pass positional arguments to
_PyObject_FastCall().
_PyObject_Call_Prepend() now uses a small stack of 5 arguments (40 bytes)
instead of 8 (64 bytes), since it is modified to use _PY_FASTCALL_SMALL_STACK.
Rewrite all comments to use the same style than other Python header files:
comment functions *before* their declaration, no newline between the comment
and the declaration.
Reformat some comments, add newlines, to make them easier to read.
Quote argument like 'arg' to mention an argument in a comment.
Issue #28838: Rename parameters of the "calls" functions of the Python C API.
* Rename 'callable_object' and 'func' to 'callable': any Python callable object
is accepted, not only Python functions
* Rename 'method' and 'nameid' to 'name' (method name)
* Rename 'o' to 'obj'
* Move, fix and update documentation of PyObject_CallXXX() functions
in abstract.h
* Update also the documentaton of the C API (update parameter names)
Replace
_PyObject_CallArg1(func, arg)
with
PyObject_CallFunctionObjArgs(func, arg, NULL)
Using the _PyObject_CallArg1() macro increases the usage of the C stack, which
was unexpected and unwanted. PyObject_CallFunctionObjArgs() doesn't have this
issue.
* Callable object: callable, o, callable_object => func
* Object for method calls: o => obj
* Method name: name or nameid => method
Cleanup also the C code:
* Don't initialize variables to NULL if they are not used before their first
assignement
* Add braces for readability
* BUILD_TUPLE_UNPACK and BUILD_MAP_UNPACK_WITH_CALL no longer generated with
single tuple or dict.
* Restored more informative error messages for incorrect var-positional and
var-keyword arguments.
* Removed code duplications in _PyEval_EvalCodeWithName().
* Removed redundant runtime checks and parameters in _PyStack_AsDict().
* Added a workaround and enabled previously disabled test in test_traceback.
* Removed dead code from the dis module.
Issue #27810: Add a new calling convention for C functions:
PyObject* func(PyObject *self, PyObject **args,
Py_ssize_t nargs, PyObject *kwnames);
Where args is a C array of positional arguments followed by values of keyword
arguments. nargs is the number of positional arguments, kwnames are keys of
keyword arguments. kwnames can be NULL.
Issue #27830: Add _PyObject_FastCallKeywords(): avoid the creation of a
temporary dictionary for keyword arguments.
Other changes:
* Cleanup call_function() and fast_function() (ex: rename nk to nkwargs)
* Remove now useless do_call(), replaced with _PyObject_FastCallKeywords()
Issue #27841: Add _PyObject_Call_Prepend() helper function to prepend an
argument to existing arguments to call a function. This helper uses fast calls.
Modify method_call() and slot_tp_new() to use _PyObject_Call_Prepend().
Min ho Kim
Victor Stinner
Zackery Spytz
Serhiy Storchaka
Christian Tismer
Andrew Svetlov
Ville Skyttä
Victor Stinner
Benjamin Peterson
Martin Panter
Raymond Hettinger