* 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`.
Add an option (--enable-experimental-jit for configure-based builds
or --experimental-jit for PCbuild-based ones) to build an
*experimental* just-in-time compiler, based on copy-and-patch (https://fredrikbk.com/publications/copy-and-patch.pdf).
See Tools/jit/README.md for more information on how to install the required build-time tooling.
* gh-112529: Implement GC for free-threaded builds
This implements a mark and sweep GC for the free-threaded builds of
CPython. The implementation relies on mimalloc to find GC tracked
objects (i.e., "containers").
* Bring in a subset of biased reference counting:
https://github.com/colesbury/nogil/commit/b6b12a9a94e
The NoGIL branch has functions for attempting to do an incref on an object which may or may not be in flight. This just brings those functions over so that they will be usable from in the dict implementation to get items w/o holding a lock.
There's a handful of small simple modifications:
Adding inline to the force inline functions to avoid a warning, and switching from _Py_ALWAYS_INLINE to Py_ALWAYS_INLINE as that's available
Remove _Py_REF_LOCAL_SHIFT as it doesn't exist yet (and is currently 0 in the 3.12 nogil branch anyway)
ob_ref_shared is currently Py_ssize_t and not uint32_t, so use that
_PY_LIKELY doesn't exist, so drop it
_Py_ThreadLocal becomes _Py_IsOwnedByCurrentThread
Add '_PyInterpreterState_GET()' to _Py_IncRefTotal calls.
Co-Authored-By: Sam Gross <colesbury@gmail.com>
There is a WIP proposal to enable webassembly stack switching which have been
implemented in v8:
https://github.com/WebAssembly/js-promise-integration
It is not possible to switch stacks that contain JS frames so the Emscripten JS
trampolines that allow calling functions with the wrong number of arguments
don't work in this case. However, the js-promise-integration proposal requires
the [type reflection for Wasm/JS API](https://github.com/WebAssembly/js-types)
proposal, which allows us to actually count the number of arguments a function
expects.
For better compatibility with stack switching, this PR checks if type reflection
is available, and if so we use a switch block to decide the appropriate
signature. If type reflection is unavailable, we should use the current EMJS
trampoline.
We cache the function argument counts since when I didn't cache them performance
was negatively affected.
Co-authored-by: T. Wouters <thomas@python.org>
Co-authored-by: Brett Cannon <brett@python.org>
pycore_create_interpreter() now returns a status, rather than
calling Py_FatalError().
* PyInterpreterState_New() now calls Py_ExitStatusException() instead
of calling Py_FatalError() directly.
* Replace Py_FatalError() with PyStatus in init_interpreter() and
_PyObject_InitState().
* _PyErr_SetFromPyStatus() now raises RuntimeError, instead of
ValueError. It can now call PyErr_NoMemory(), raise MemoryError,
if it detects _PyStatus_NO_MEMORY() error message.
Python built with "configure --with-trace-refs" (tracing references)
is now ABI compatible with Python release build and debug build.
Moreover, it now also supports the Limited API.
Change Py_TRACE_REFS build:
* Remove _PyObject_EXTRA_INIT macro.
* The PyObject structure no longer has two extra members (_ob_prev
and _ob_next).
* Use a hash table (_Py_hashtable_t) to trace references (all
objects): PyInterpreterState.object_state.refchain.
* Py_TRACE_REFS build is now ABI compatible with release build and
debug build.
* Limited C API extensions can now be built with Py_TRACE_REFS:
xxlimited, xxlimited_35, _testclinic_limited.
* No longer rename PyModule_Create2() and PyModule_FromDefAndSpec2()
functions to PyModule_Create2TraceRefs() and
PyModule_FromDefAndSpec2TraceRefs().
* _Py_PrintReferenceAddresses() is now called before
finalize_interp_delete() which deletes the refchain hash table.
* test_tracemalloc find_trace() now also filters by size to ignore
the memory allocated by _PyRefchain_Trace().
Test changes for Py_TRACE_REFS:
* Add test.support.Py_TRACE_REFS constant.
* Add test_sys.test_getobjects() to test sys.getobjects() function.
* test_exceptions skips test_recursion_normalizing_with_no_memory()
and test_memory_error_in_PyErr_PrintEx() if Python is built with
Py_TRACE_REFS.
* test_repl skips test_no_memory().
* test_capi skisp test_set_nomemory().
There is no need to export the _Py_ForgetReference() function of the
Py_TRACE_REFS build. It's not used by shared extensions. Enhance also
its comment.
No longer export these 5 internal C API functions:
* _PyArena_AddPyObject()
* _PyArena_Free()
* _PyArena_Malloc()
* _PyArena_New()
* _Py_FatalRefcountErrorFunc()
Change comment style to "// comment" and add comment explaining why
other functions have to be exported.
* Add missing includes.
* Remove unused includes.
* Update old include/symbol names to newer names.
* Mention at least one included symbol.
* Sort includes.
* Update Tools/cases_generator/generate_cases.py used to generated
pycore_opcode_metadata.h.
* Update Parser/asdl_c.py used to generate pycore_ast.h.
* Cleanup also includes in _testcapimodule.c and _testinternalcapi.c.
The linked list of objects was a global variable, which broke isolation between interpreters, causing crashes. To solve this, we've moved the linked list to each interpreter.
No longer export these 5 internal C API variables:
* _PyBufferWrapper_Type
* _PyImport_FrozenBootstrap
* _PyImport_FrozenStdlib
* _PyImport_FrozenTest
* _Py_SwappedOp
Fix the definition of these internal functions, replace PyAPI_DATA()
with PyAPI_FUNC():
* _PyImport_ClearExtension()
* _PyObject_IsFreed()
* _PyThreadState_GetCurrent()
No longer export these 2 internal C API functions:
* _PyEval_SignalAsyncExc()
* _PyEval_SignalReceived()
Add also comments explaining why some internal functions have to be
exported, and update existing comments.
Move private _PyObject and private _PyType functions to the internal
C API (pycore_object.h):
* _PyObject_GetMethod()
* _PyObject_IsAbstract()
* _PyObject_NextNotImplemented()
* _PyType_CalculateMetaclass()
* _PyType_GetDocFromInternalDoc()
* _PyType_GetTextSignatureFromInternalDoc()
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.
* gcmodule.c reuses _Py_AS_GC(op) for AS_GC()
* Move gcmodule.c FROM_GC() implementation to a new _Py_FROM_GC()
static inline function in pycore_gc.h.
* _PyObject_IS_GC(): only get the type once
* gc_is_finalized(à) and PyObject_GC_IsFinalized() use
_PyGC_FINALIZED(), instead of _PyGCHead_FINALIZED().
* Remove _Py_CAST() in pycore_gc.h: this header file is not built
with C++.
In gh-103912 we added tp_bases and tp_mro to each PyInterpreterState.types.builtins entry. However, doing so ignored the fact that both PyTypeObject fields are public API, and not documented as internal (as opposed to tp_subclasses). We address that here by reverting back to shared objects, making them immortal in the process.
This is the implementation of PEP683
Motivation:
The PR introduces the ability to immortalize instances in CPython which bypasses reference counting. Tagging objects as immortal allows up to skip certain operations when we know that the object will be around for the entire execution of the runtime.
Note that this by itself will bring a performance regression to the runtime due to the extra reference count checks. However, this brings the ability of having truly immutable objects that are useful in other contexts such as immutable data sharing between sub-interpreters.
* Eliminate all remaining uses of Py_SIZE and Py_SET_SIZE on PyLongObject, adding asserts.
* Change layout of size/sign bits in longobject to support future addition of immortal ints and tagged medium ints.
* Add functions to hide some internals of long object, and for setting sign and digit count.
* Replace uses of IS_MEDIUM_VALUE macro with _PyLong_IsCompact().
Moving it valuable with a per-interpreter GIL. However, it is also useful without one, since it allows us to identify refleaks within a single interpreter or where references are escaping an interpreter. This becomes more important as we move the obmalloc state to PyInterpreterState.
https://github.com/python/cpython/issues/102304
The essentially eliminates the global variable, with the associated benefits. This is also a precursor to isolating this bit of state to PyInterpreterState.
Folks that currently read _Py_RefTotal directly would have to start using _Py_GetGlobalRefTotal() instead.
https://github.com/python/cpython/issues/102304
When __getattr__ is defined, python with try to find an attribute using _PyObject_GenericGetAttrWithDict
find nothing is reasonable so we don't need an exception, it will hurt performance.
Convert macros to static inline functions to avoid macro pitfalls,
like duplication of side effects:
* DK_ENTRIES()
* DK_UNICODE_ENTRIES()
* PyCode_GetNumFree()
* PyFloat_AS_DOUBLE()
* PyInstanceMethod_GET_FUNCTION()
* PyMemoryView_GET_BASE()
* PyMemoryView_GET_BUFFER()
* PyMethod_GET_FUNCTION()
* PyMethod_GET_SELF()
* PySet_GET_SIZE()
* _PyHeapType_GET_MEMBERS()
Changes:
* PyCode_GetNumFree() casts PyCode_GetNumFree.co_nfreevars from int
to Py_ssize_t to be future proof, and because Py_ssize_t is
commonly used in the C API.
* PyCode_GetNumFree() doesn't cast its argument: the replaced macro
already required the exact type PyCodeObject*.
* Add assertions in some functions using "CAST" macros to check
the arguments type when Python is built with assertions
(debug build).
* Remove an outdated comment in unicodeobject.h.
* Store tp_weaklist on the interpreter state for static builtin types.
* Factor out _PyStaticType_GET_WEAKREFS_LISTPTR().
* Add _PyStaticType_ClearWeakRefs().
* Add a comment about how _PyStaticType_ClearWeakRefs() loops.
* Document the change.
* Update Doc/whatsnew/3.12.rst
* Fix a typo.
* Add _Py_memory_repeat function to pycore_list
* Add _Py_RefcntAdd function to pycore_object
* Use the new functions in tuplerepeat, list_repeat, and list_inplace_repeat
Mark Shannon
Sam Gross
Brandt Bucher
Dino Viehland
Hugo van Kemenade
Hood Chatham
Victor Stinner
Serhiy Storchaka
Eric Snow
Petr Viktorin
Eddie Elizondo
Nikita Sobolev
wangxiang-hz
Ikko Ashimine
Pieter Eendebak
Kumar Aditya