Add the ability to enable/disable the GIL at runtime, and use that in
the C module loading code.
We can't know before running a module init function if it supports
free-threading, so the GIL is temporarily enabled before doing so. If
the module declares support for running without the GIL, the GIL is
later disabled. Otherwise, the GIL is permanently enabled, and will
never be disabled again for the life of the current interpreter.
This PR adds the ability to enable the GIL if it was disabled at
interpreter startup, and modifies the multi-phase module initialization
path to enable the GIL when loading a module, unless that module's spec
includes a slot indicating it can run safely without the GIL.
PEP 703 called the constant for the slot `Py_mod_gil_not_used`; I went
with `Py_MOD_GIL_NOT_USED` for consistency with gh-104148.
A warning will be issued up to once per interpreter for the first
GIL-using module that is loaded. If `-v` is given, a shorter message
will be printed to stderr every time a GIL-using module is loaded
(including the first one that issues a warning).
The function returns `True` or `False` depending on whether the GIL is
currently enabled. In the default build, it always returns `True`
because the GIL is always enabled.
The code for Tier 2 is now only compiled when configured
with `--enable-experimental-jit[=yes|interpreter]`.
We drop support for `PYTHON_UOPS` and -`Xuops`,
but you can disable the interpreter or JIT
at runtime by setting `PYTHON_JIT=0`.
You can also build it without enabling it by default
using `--enable-experimental-jit=yes-off`;
enable with `PYTHON_JIT=1`.
On Windows, the `build.bat` script supports
`--experimental-jit`, `--experimental-jit-off`,
`--experimental-interpreter`.
In the C code, `_Py_JIT` is defined as before
when the JIT is enabled; the new variable
`_Py_TIER2` is defined when the JIT *or* the
interpreter is enabled. It is actually a bitmask:
1: JIT; 2: default-off; 4: interpreter.
These are cleanups I've pulled out of gh-118116. Mostly, this change moves code around to align with some future changes and to improve clarity a little. There is one very small change in behavior: we now add the module to the per-interpreter caches after updating the global state, rather than before.
In free-threaded builds, running with `PYTHON_GIL=0` will now disable the
GIL. Follow-up issues track work to re-enable the GIL when loading an
incompatible extension, and to disable the GIL by default.
In order to support re-enabling the GIL at runtime, all GIL-related data
structures are initialized as usual, and disabling the GIL simply sets a flag
that causes `take_gil()` and `drop_gil()` to return early.
* gh-112529: Remove PyGC_Head from object pre-header in free-threaded build
This avoids allocating space for PyGC_Head in the free-threaded build.
The GC implementation for free-threaded CPython does not use the
PyGC_Head structure.
* The trashcan mechanism uses the `ob_tid` field instead of `_gc_prev`
in the free-threaded build.
* The GDB libpython.py file now determines the offset of the managed
dict field based on whether the running process is a free-threaded
build. Those are identified by the `ob_ref_local` field in PyObject.
* Fixes `_PySys_GetSizeOf()` which incorrectly incorrectly included the
size of `PyGC_Head` in the size of static `PyTypeObject`.
This replaces some usages of PyThread_type_lock with PyMutex, which does not require memory allocation to initialize.
This simplifies some of the runtime initialization and is also one step towards avoiding changing the default raw memory allocator during initialize/finalization, which can be non-thread-safe in some circumstances.
_PyDict_Pop_KnownHash(): remove the default value and the return type
becomes an int.
Co-authored-by: Stefan Behnel <stefan_ml@behnel.de>
Co-authored-by: Antoine Pitrou <pitrou@free.fr>
sys.audit() now has assertions to check that the event argument is
not NULL and that the format argument does not use the "N" format.
Add tests on PySys_AuditTuple().
* Remove unused <locale.h> includes.
* Remove unused <fcntl.h> include in traceback.h.
* Remove redundant <assert.h> and <stddef.h> includes. They are already
included by "Python.h".
* Remove <object.h> include in faulthandler.c. Python.h already includes it.
* Add missing <stdbool.h> in pycore_pythread.h if HAVE_PTHREAD_STUBS
is defined.
* Fix also warnings in pthread_stubs.h: don't redefine macros if they
are already defined, like the __NEED_pthread_t macro.
Statistics gathering is now off by default. Use the "-X pystats"
command line option or set the new PYTHONSTATS environment variable
to 1 to turn statistics gathering on at Python startup.
Statistics are no longer dumped at exit if statistics gathering was
off or statistics have been cleared.
Changes:
* Add PYTHONSTATS environment variable.
* sys._stats_dump() now returns False if statistics are not dumped
because they are all equal to zero.
* Add PyConfig._pystats member.
* Add tests on sys functions and on setting PyConfig._pystats to 1.
* Add Include/cpython/pystats.h and Include/internal/pycore_pystats.h
header files.
* Rename '_py_stats' variable to '_Py_stats'.
* Exclude Include/cpython/pystats.h from the Py_LIMITED_API.
* Move pystats.h include from object.h to Python.h.
* Add _Py_StatsOn() and _Py_StatsOff() functions. Remove
'_py_stats_struct' variable from the API: make it static in
specialize.c.
* Document API in Include/pystats.h and Include/cpython/pystats.h.
* Complete pystats documentation in Doc/using/configure.rst.
* Don't write "all zeros" stats: if _stats_off() and _stats_clear()
or _stats_dump() were called.
* _PyEval_Fini() now always call _Py_PrintSpecializationStats() which
does nothing if stats are all zeros.
Co-authored-by: Michael Droettboom <mdboom@gmail.com>
Move private functions to the internal C API (pycore_sysmodule.h):
* _PySys_GetAttr()
* _PySys_GetSizeOf()
No longer export most of these functions.
Fix also a typo in Include/cpython/optimizer.h: add a missing space.
Remove the internal _PyDict_GetItemStringWithError() function. It can
now be replaced with the new public PyDict_ContainsString() and
PyDict_GetItemStringRef() functions.
getargs.c now now uses a strong reference for current_arg.
find_keyword() returns a strong reference.
Move private _PyDict functions to the internal C API (pycore_dict.h):
* _PyDict_Contains_KnownHash()
* _PyDict_DebugMallocStats()
* _PyDict_DelItemIf()
* _PyDict_GetItemWithError()
* _PyDict_HasOnlyStringKeys()
* _PyDict_MaybeUntrack()
* _PyDict_MergeEx()
No longer export these functions.
Move private debug _PyObject functions to the internal C API
(pycore_object.h):
* _PyDebugAllocatorStats()
* _PyObject_CheckConsistency()
* _PyObject_DebugTypeStats()
* _PyObject_IsFreed()
No longer export most of these functions, except of
_PyObject_IsFreed().
Move test functions using _PyObject_IsFreed() from _testcapi to
_testinternalcapi. check_pyobject_is_freed() test no longer catch
_testcapi.error: the tested function cannot raise _testcapi.error.
Remove the following functions from the C API, move them to the internal C
API: add a new pycore_modsupport.h internal header file:
* PyModule_CreateInitialized()
* _PyArg_NoKwnames()
* _Py_VaBuildStack()
No longer export these functions.
Remove old aliases which were kept backwards compatibility with
Python 3.8:
* _PyObject_CallMethodNoArgs()
* _PyObject_CallMethodOneArg()
* _PyObject_CallOneArg()
* _PyObject_FastCallDict()
* _PyObject_Vectorcall()
* _PyObject_VectorcallMethod()
* _PyVectorcall_Function()
Update code which used these aliases to use new names.
Hugo van Kemenade
Brett Simmers
Jeong, YunWon
Petr Viktorin
Pablo Galindo Salgado
Tian Gao
Sam Gross
Guido van Rossum
Eric Snow
Victor Stinner
Serhiy Storchaka
Nikita Sobolev
Michael Droettboom
Brandt Bucher
Inada Naoki
gsallam
Donghee Na
Mark Shannon
Erlend E. Aasland
Erlend E. Aasland