Add new trashcan macros to deal with a double deallocation that could occur when the `tp_dealloc` of a subclass calls the `tp_dealloc` of a base class and that base class uses the trashcan mechanism.
Patch by Jeroen Demeyer.
* _PyTuple_ITEMS() gives access to the tuple->ob_item field and cast the
first argument to PyTupleObject*. This internal macro is only usable if
Py_BUILD_CORE is defined.
* Replace &PyTuple_GET_ITEM(ob, 0) with _PyTuple_ITEMS(ob).
* Replace PyTuple_GET_ITEM(op, 1) with &_PyTuple_ITEMS(ob)[1].
property_descr_get() uses a "cached" tuple to optimize function
calls. But this tuple can be discovered in debug mode with
sys.getobjects(). Remove the optimization, it's not really worth it
and it causes 3 different crashes last years.
Microbenchmark:
./python -m perf timeit -v \
-s "from collections import namedtuple; P = namedtuple('P', 'x y'); p = P(1, 2)" \
--duplicate 1024 "p.x"
Result:
Mean +- std dev: [ref] 32.8 ns +- 0.8 ns -> [patch] 40.4 ns +- 1.3 ns: 1.23x slower (+23%)
* The hash of BuiltinMethodType instances no longer depends on the hash
of __self__. It depends now on the hash of id(__self__).
* The hash and equality of ModuleType and MethodWrapperType instances no
longer depend on the hash and equality of __self__. They depend now on
the hash and equality of id(__self__).
* MethodWrapperType instances no longer support ordering.
METH_NOARGS functions need only a single argument but they are cast
into a PyCFunction, which takes two arguments. This triggers an
invalid function cast warning in gcc8 due to the argument mismatch.
Fix this by adding a dummy unused argument.
* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals
Other globals are excluded (see globals.txt and check-c-globals.py).
Issue #29259, #29263. methoddescr_call() creates a PyCFunction object, call it
and the destroy it. Add a new _PyMethodDef_RawFastCallDict() method to avoid
the temporary PyCFunction object.
Issue #28915: Replace PyObject_CallFunction() with
PyObject_CallFunctionObjArgs() when the format string was only made of "O"
formats, PyObject* arguments.
PyObject_CallFunctionObjArgs() avoids the creation of a temporary tuple and
doesn't have to parse a format string.
Issue #28915: Replace _PyObject_CallMethodId() with
_PyObject_CallMethodIdObjArgs() when the format string only use the format 'O'
for objects, like "(O)".
_PyObject_CallMethodIdObjArgs() avoids the code to parse a format string and
avoids the creation of a temporary tuple.
Issue #28858: The change b9c9691c72c5 introduced a regression. It seems like
_PyObject_CallArg1() uses more stack memory than
PyObject_CallFunctionObjArgs().
* PyObject_CallFunctionObjArgs(func, NULL) => _PyObject_CallNoArg(func)
* PyObject_CallFunctionObjArgs(func, arg, NULL) => _PyObject_CallArg1(func, arg)
PyObject_CallFunctionObjArgs() allocates 40 bytes on the C stack and requires
extra work to "parse" C arguments to build a C array of PyObject*.
_PyObject_CallNoArg() and _PyObject_CallArg1() are simpler and don't allocate
memory on the C stack.
This change is part of the fastcall project. The change on listsort() is
related to the issue #23507.
Serhiy Storchaka
Jeroen Demeyer
Steve Dower
Inada Naoki
Victor Stinner
Siddhesh Poyarekar
Oren Milman
stratakis
Eric Snow
Victor Stinner
Benjamin Peterson
Raymond Hettinger