Make a non-Py_DEBUG, asserts-enabled build of CPython possible. This means
making sure helper functions are defined when NDEBUG is not defined, not
just when Py_DEBUG is defined.
Also fix a division-by-zero in obmalloc.c that went unnoticed because in Py_DEBUG mode, elsize is never zero.
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>
add_methods(), add_members(), and add_getset() used PyDict_SetItemString()
to register descriptor to the type's dict.
So descr_new() and PyDict_SetItemString() creates interned unicode from same
C string.
This patch takes interned unicode from descriptor, and use PyDict_SetItem()
instead of PyDict_SetItemString().
python_startup_no_site:
default: Median +- std dev: 12.7 ms +- 0.1 ms
patched: Median +- std dev: 12.5 ms +- 0.1 ms
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.
