We're no longer using _Py_IDENTIFIER() (or _Py_static_string()) in any core CPython code. It is still used in a number of non-builtin stdlib modules.
The replacement is: PyUnicodeObject (not pointer) fields under _PyRuntimeState, statically initialized as part of _PyRuntime. A new _Py_GET_GLOBAL_IDENTIFIER() macro facilitates lookup of the fields (along with _Py_GET_GLOBAL_STRING() for non-identifier strings).
https://bugs.python.org/issue46541#msg411799 explains the rationale for this change.
The core of the change is in:
* (new) Include/internal/pycore_global_strings.h - the declarations for the global strings, along with the macros
* Include/internal/pycore_runtime_init.h - added the static initializers for the global strings
* Include/internal/pycore_global_objects.h - where the struct in pycore_global_strings.h is hooked into _PyRuntimeState
* Tools/scripts/generate_global_objects.py - added generation of the global string declarations and static initializers
I've also added a --check flag to generate_global_objects.py (along with make check-global-objects) to check for unused global strings. That check is added to the PR CI config.
The remainder of this change updates the core code to use _Py_GET_GLOBAL_IDENTIFIER() instead of _Py_IDENTIFIER() and the related _Py*Id functions (likewise for _Py_GET_GLOBAL_STRING() instead of _Py_static_string()). This includes adding a few functions where there wasn't already an alternative to _Py*Id(), replacing the _Py_Identifier * parameter with PyObject *.
The following are not changed (yet):
* stop using _Py_IDENTIFIER() in the stdlib modules
* (maybe) get rid of _Py_IDENTIFIER(), etc. entirely -- this may not be doable as at least one package on PyPI using this (private) API
* (maybe) intern the strings during runtime init
https://bugs.python.org/issue46541
Add _PyUnicode_FiniTypes() function, called by
finalize_interp_types(). It clears these static types:
* EncodingMapType
* PyFieldNameIter_Type
* PyFormatterIter_Type
_PyStaticType_Dealloc() now does nothing if tp_subclasses
is not NULL.
* Move PyContext static types into object.c static_types list.
* Rename PyContextTokenMissing_Type to _PyContextTokenMissing_Type
and declare it in pycore_context.h.
* _PyHamtItems types are no long exported: replace PyAPI_DATA() with
extern.
Add types removed by mistake by the commit adding
_PyTypes_FiniTypes().
Move also PyBool_Type at the end, since it depends on PyLong_Type.
PyBytes_Type and PyUnicode_Type no longer depend explicitly on
PyBaseObject_Type: it's the default of PyType_Ready().
Add _PyTypes_FiniTypes() best-effort function to clear static types:
don't deallocate a type if it still has subclasses.
remove_subclass() now sets tp_subclasses to NULL when removing the
last subclass.
This change is strictly renames and moving code around. It helps in the following ways:
* ensures type-related init functions focus strictly on one of the three aspects (state, objects, types)
* passes in PyInterpreterState * to all those functions, simplifying work on moving types/objects/state to the interpreter
* consistent naming conventions help make what's going on more clear
* keeping API related to a type in the corresponding header file makes it more obvious where to look for it
https://bugs.python.org/issue46008
Rename Include/namespaceobject.h to
Include/internal/pycore_namespace.h.
The _testmultiphase extension is now built with the
Py_BUILD_CORE_MODULE macro defined to access _PyNamespace_Type.
object.c: remove unused "pycore_context.h" include.
* Never change types' cached keys. It could invalidate inline attribute objects.
* Lazily create object dictionaries.
* Update specialization of LOAD/STORE_ATTR.
* Don't update shared keys version for deletion of value.
* Update gdb support to handle instance values.
* Rename SPLIT_KEYS opcodes to INSTANCE_VALUE.
* Move _PyObject_CallNoArgs() to pycore_call.h (internal C API).
* _ssl, _sqlite and _testcapi extensions now call the public
PyObject_CallNoArgs() function, rather than _PyObject_CallNoArgs().
* _lsprof extension is now built with Py_BUILD_CORE_MODULE macro
defined to get access to internal _PyObject_CallNoArgs().
Fix typo in the private _PyObject_CallNoArg() function name: rename
it to _PyObject_CallNoArgs() to be consistent with the public
function PyObject_CallNoArgs().
_PyObject_GetMethod() now uses _PyType_IsReady() to decide if
PyType_Ready() must be called or not, rather than testing if
tp->tp_dict is NULL.
Move also variable declarations closer to where they are used, and
use Py_NewRef().
Remove 4 C API private trashcan functions which were only kept for
the backward compatibility of the stable ABI with Python 3.8 and
older, since the trashcan API was not usable with the limited C API
on Python 3.8 and older. The trashcan API was excluded from the
limited C API in Python 3.9.
Removed functions:
* _PyTrash_deposit_object()
* _PyTrash_destroy_chain()
* _PyTrash_thread_deposit_object()
* _PyTrash_thread_destroy_chain()
The trashcan C API was never usable with the limited C API, since old
trashcan macros accessed directly PyThreadState members like
"_tstate->trash_delete_nesting", whereas the PyThreadState structure
is opaque in the limited C API.
Exclude also the PyTrash_UNWIND_LEVEL constant from the C API.
The trashcan C API was modified in Python 3.9 by commit
38965ec541 and in Python 3.10 by commit
ed1a5a5bac to hide implementation
details.
When printing AttributeError, PyErr_Display will offer suggestions of similar
attribute names in the object that the exception was raised from:
>>> collections.namedtoplo
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: namedtuple?
Add the Py_Is(x, y) function to test if the 'x' object is the 'y'
object, the same as "x is y" in Python. Add also the Py_IsNone(),
Py_IsTrue(), Py_IsFalse() functions to test if an object is,
respectively, the None singleton, the True singleton or the False
singleton.
The limited C API is now supported if Python is built in debug mode
(if the Py_DEBUG macro is defined). In the limited C API, the
Py_INCREF() and Py_DECREF() functions are now implemented as opaque
function calls, rather than accessing directly the PyObject.ob_refcnt
member, if Python is built in debug mode and the Py_LIMITED_API macro
targets Python 3.10 or newer. It became possible to support the
limited C API in debug mode because the PyObject structure is the
same in release and debug mode since Python 3.8 (see bpo-36465).
The limited C API is still not supported in the --with-trace-refs
special build (Py_TRACE_REFS macro).
No longer use deprecated aliases to functions:
* Replace PyObject_MALLOC() with PyObject_Malloc()
* Replace PyObject_REALLOC() with PyObject_Realloc()
* Replace PyObject_FREE() with PyObject_Free()
* Replace PyObject_Del() with PyObject_Free()
* Replace PyObject_DEL() with PyObject_Free()
The Py_TRASHCAN_BEGIN macro no longer accesses PyTypeObject attributes,
but now can get the condition by calling the new private
_PyTrash_cond() function which hides implementation details.
The PyObject_INIT() and PyObject_INIT_VAR() macros become aliases to,
respectively, PyObject_Init() and PyObject_InitVar() functions.
Rename _PyObject_INIT() and _PyObject_INIT_VAR() static inline
functions to, respectively, _PyObject_Init() and _PyObject_InitVar(),
and move them to pycore_object.h. Remove their return value:
their return type becomes void.
The _datetime module is now built with the Py_BUILD_CORE_MODULE macro
defined.
Remove an outdated comment on _Py_tracemalloc_config.
The PEP 353, written in 2005, introduced PY_FORMAT_SIZE_T. Python no
longer supports macOS 10.4 and Visual Studio 2010, but requires more
recent macOS and Visual Studio versions. In 2020 with Python 3.10, it
is now safe to use directly "%zu" to format size_t and "%zi" to
format Py_ssize_t.
Module C state is now accessible from C-defined heap type methods (PEP 573).
Patch by Marcel Plch and Petr Viktorin.
Co-authored-by: Marcel Plch <mplch@redhat.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
PyType_HasFeature() now always calls PyType_GetFlags() to hide
implementation details. Previously, it accessed directly the
PyTypeObject.tp_flags member when the limited C API was not used.
Add fast inlined version _PyType_HasFeature() and _PyType_IS_GC()
for object.c and typeobject.c.
The PyObject_NEW() macro becomes an alias to the PyObject_New()
macro, and the PyObject_NEW_VAR() macro becomes an alias to the
PyObject_NewVar() macro, to hide implementation details. They no
longer access directly the PyTypeObject.tp_basicsize member.
Exclude _PyObject_SIZE() and _PyObject_VAR_SIZE() macros from
the limited C API.
Replace PyObject_NEW() with PyObject_New() and replace
PyObject_NEW_VAR() with PyObject_NewVar().
Convert the PyObject_GET_WEAKREFS_LISTPTR() macro to a function to
hide implementation details: the macro accessed directly to the
PyTypeObject.tp_weaklistoffset member.
Add _PyObject_GET_WEAKREFS_LISTPTR() static inline function to the
internal C API.
Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro no longer
access PyThreadState attributes, but call new private
_PyTrash_begin() and _PyTrash_end() functions which hide
implementation details.
Move the static inline function flavor of Py_EnterRecursiveCall() and
Py_LeaveRecursiveCall() to the internal C API: they access
PyThreadState attributes. The limited C API provides regular
functions which hide implementation details.
In the limited C API, PyObject_INIT() and PyObject_INIT_VAR() are now
defined as aliases to PyObject_Init() and PyObject_InitVar() to make
their implementation opaque. It avoids to leak implementation details
in the limited C API.
Exclude the following functions from the limited C API, move them
from object.h to cpython/object.h:
* _Py_NewReference()
* _Py_ForgetReference()
* _PyTraceMalloc_NewReference()
* _Py_GetRefTotal()
The macro is defined after Py_DECREF() and so is no longer used by
Py_DECREF().
Moving _Py_Dealloc() macro back from cpython/object.h to object.h
would require to move a lot of definitions as well: PyTypeObject and
many related types used by PyTypeObject.
Keep _Py_Dealloc() as an opaque function call to avoid leaking
implementation details in the limited C API (object.h): remove
_Py_Dealloc() macro from cpython/object.h.
_Py_NewReference() becomes a regular opaque function, rather than a
static inline function in the C API (object.h), to better hide
implementation details.
Move _Py_tracemalloc_config from public pymem.h to internal
pycore_pymem.h header.
Make _Py_AddToAllObjects() private.
* Remove _Py_INC_REFTOTAL and _Py_DEC_REFTOTAL macros: modify
directly _Py_RefTotal.
* _Py_ForgetReference() is no longer defined if the Py_TRACE_REFS
macro is not defined.
* Remove _Py_NewReference() implementation from object.c:
unify the two implementations in object.h inline function.
* Fix Py_TRACE_REFS build: _Py_INC_TPALLOCS() macro has been removed.
Rename init_slotdefs() to _PyTypes_InitSlotDefs() and add a return
value of type PyStatus. The function is now called exactly once from
_PyTypes_Init(). Replace calls to init_slotdefs() with an assertion
checking that slotdefs is initialized.
Replace Py_FatalError() with _PyObject_ASSERT_FAILED_MSG() in
object.c and typeobject.c to also dump the involved Python object on
a fatal error. It should ease debug when such fatal error occurs.
If the double linked list is inconsistent, _Py_ForgetReference() no
longer dumps previous and next objects in the fatal error, it now
only dumps the current object. It ensures that the error message
is displayed even if dumping the object does crash Python.
Enhance _Py_ForgetReference() error messages;
_PyObject_ASSERT_FAILED_MSG() logs the "_Py_ForgetReference" function
name.
Additional note: the `method_check_args` function in `Objects/descrobject.c` is written in such a way that it applies to all kinds of descriptors. In particular, a future re-implementation of `wrapper_descriptor` could use that code.
CC @vstinner @encukou
https://bugs.python.org/issue37645
Automerge-Triggered-By: @encukou
* Add _Py_EnterRecursiveCall() and _Py_LeaveRecursiveCall() which
require a tstate argument.
* Pass tstate to _Py_MakeRecCheck() and _Py_CheckRecursiveCall().
* Convert Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() macros
to static inline functions.
_PyThreadState_GET() is the most efficient way to get the tstate, and
so using it with _Py_EnterRecursiveCall() and
_Py_LeaveRecursiveCall() should be a little bit more efficient than
using Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() which use
the "slower" PyThreadState_GET().
Some objects like Py_None are not initialized with conventional means
that prepare the circular linked list pointers, leaving them unlinked
from the rest of the objects. For those objects, NULL pointers does
not mean that they are freed, so we need to skip the check in those
cases.
bpo-36389, bpo-38376: The _PyObject_CheckConsistency() function is
now also available in release mode. For example, it can be used to
debug a crash in the visit_decref() function of the GC.
Modify the following functions to also work in release mode:
* _PyDict_CheckConsistency()
* _PyObject_CheckConsistency()
* _PyType_CheckConsistency()
* _PyUnicode_CheckConsistency()
Other changes:
* _PyMem_IsPtrFreed(ptr) now also returns 1 if ptr is NULL
(equals to 0).
* _PyBytesWriter_CheckConsistency() now returns 1 and is only used
with assert().
* Reorder _PyObject_Dump() to write safe fields first, and only
attempt to render repr() at the end.
It is now allowed to add new fields at the end of the PyTypeObject struct without having to allocate a dedicated compatibility flag in tp_flags.
This will reduce the risk of running out of bits in the 32-bit tp_flags value.
* Add _PyInitError functions:
* _PyInitError_Ok()
* _PyInitError_Error()
* _PyInitError_NoMemory()
* _PyInitError_Exit()
* _PyInitError_IsError()
* _PyInitError_IsExit()
* _PyInitError_Failed()
* frozenmain.c and _testembed.c now use functions rather than macros.
* Move _Py_INIT_xxx() macros to the internal API.
* Move _PyWstrList_INIT macro to the internal API.
Add a new _PyObject_CheckConsistency() function which can be used to
help debugging. The function is available in release mode.
Add a 'check_content' parameter to _PyDict_CheckConsistency().
Modify CLEANBYTE, DEADDYTE and FORBIDDENBYTE constants: use 0xCD,
0xDD and 0xFD, rather than 0xCB, 0xBB and 0xFB, to use the same byte
patterns than Windows CRT debug malloc() and free().
Replace _PyMem_IsFreed() function with _PyMem_IsPtrFreed() inline
function. The function is now way more efficient, it became a simple
comparison on integers, rather than a short loop. It detects also
uninitialized bytes and "forbidden bytes" filled by debug hooks
on memory allocators.
Add unit tests on _PyObject_IsFreed().
* Revert "bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (#12003)"
This reverts commit bcfa450f21.
* Revert "bpo-33608: Simplify ceval's DISPATCH by hoisting eval_breaker ahead of time. (gh-12062)"
This reverts commit bda918bf65.
* Revert "bpo-33608: Use _Py_AddPendingCall() in _PyCrossInterpreterData_Release(). (gh-12024)"
This reverts commit b05b711a2c.
* Revert "bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall(). (GH-11617)"
This reverts commit ef4ac967e2.
* Split _Py_InitializeCore_impl() into subfunctions: add multiple pycore_init_xxx() functions
* Preliminary sys.stderr is now set earlier to get an usable
sys.stderr ealier.
* Move code into _Py_Initialize_ReconfigureCore() to be able to call
it from _Py_InitializeCore().
* Split _PyExc_Init(): create a new _PyBuiltins_AddExceptions()
function.
* Call _PyExc_Init() earlier in _Py_InitializeCore_impl()
and new_interpreter() to get working exceptions earlier.
* _Py_ReadyTypes() now returns _PyInitError rather than calling
Py_FatalError().
* Misc code cleanup
If _PyObject_Dump() detects that the object is freed, don't try to
dump it (exit immediately).
Enhance also _PyObject_IsFreed(): it now detects if the pointer
itself looks like freed memory.
If Py_BUILD_CORE is defined, the PyThreadState_GET() macro access
_PyRuntime which comes from the internal pycore_state.h header.
Public headers must not require internal headers.
Move PyThreadState_GET() and _PyInterpreterState_GET_UNSAFE() from
Include/pystate.h to Include/internal/pycore_state.h, and rename
PyThreadState_GET() to _PyThreadState_GET() there.
The PyThreadState_GET() macro of pystate.h is now redefined when
pycore_state.h is included, to use the fast _PyThreadState_GET().
Changes:
* Add _PyThreadState_GET() macro
* Replace "PyThreadState_GET()->interp" with
_PyInterpreterState_GET_UNSAFE()
* Replace PyThreadState_GET() with _PyThreadState_GET() in internal C
files (compiled with Py_BUILD_CORE defined), but keep
PyThreadState_GET() in the public header files.
* _testcapimodule.c: replace PyThreadState_GET() with
PyThreadState_Get(); the module is not compiled with Py_BUILD_CORE
defined.
* pycore_state.h now requires Py_BUILD_CORE to be defined.
Configuring python with ./configure --with-pydebug CFLAGS="-D COUNT_ALLOCS -O0"
makes "make smelly" fail as some symbols were being exported without the "Py_" or
"_Py" prefixes.
Changes:
* Add _PyObject_AssertFailed() function.
* Add _PyObject_ASSERT() and _PyObject_ASSERT_WITH_MSG() macros.
* gc_decref(): replace assert() with _PyObject_ASSERT_WITH_MSG() to
dump the faulty object if the assertion fails.
_PyObject_AssertFailed() calls:
* _PyMem_DumpTraceback(): try to log the traceback where the object
memory has been allocated if tracemalloc is enabled.
* _PyObject_Dump(): log repr(obj).
* Py_FatalError(): log the current Python traceback.
_PyObject_AssertFailed() uses _PyObject_IsFreed() heuristic to check
if the object memory has been freed by a debug hook on Python memory
allocators.
Initial patch written by David Malcolm.
Co-Authored-By: David Malcolm <dmalcolm@redhat.com>
* Add Py_STATIC_INLINE() macro to declare a "static inline" function.
If the compiler supports it, try to always inline the function even if no
optimization level was specified.
* Modify pydtrace.h to use Py_STATIC_INLINE() when WITH_DTRACE is
not defined.
* Add an unit test on Py_DECREF() to make sure that
_Py_NegativeRefcount() reports the correct filename.
tracemalloc now tries to update the traceback when an object is
reused from a "free list" (optimization for faster object creation,
used by the builtin list type for example).
Changes:
* Add _PyTraceMalloc_NewReference() function which tries to update
the Python traceback of a Python object.
* _Py_NewReference() now calls _PyTraceMalloc_NewReference().
* Add an unit test.
_PyObject_Dump() now uses an heuristic to check if the object memory
has been freed: log "<freed object>" in that case.
The heuristic rely on the debug hooks on Python memory allocators
which fills the memory with DEADBYTE (0xDB) when memory is
deallocated. Use PYTHONMALLOC=debug to always enable these debug
hooks.
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.
AttributeError was raised always when attribute is not found.
This commit skip raising AttributeError when `tp_getattro` is `PyObject_GenericGetAttr`.
It makes hasattr() and getattr() about 4x faster when attribute is not found.
Py_Main() now handles two more -X options:
* -X showrefcount: new _PyCoreConfig.show_ref_count field
* -X showalloccount: new _PyCoreConfig.show_alloc_count field
PR #1638, for bpo-28411, causes problems in some (very) edge cases. Until that gets sorted out, we're reverting the merge. PR #3506, a fix on top of #1638, is also getting reverted.
* Drop warnoptions from PyInterpreterState.
* Drop xoptions from PyInterpreterState.
* Don't set warnoptions and _xoptions again.
* Decref after adding to sys.__dict__.
* Drop an unused macro.
* Check sys.xoptions *before* we delete it.
* 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).
* 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).
Special thanks to INADA Naoki for pushing the patch through
the last mile, Serhiy Storchaka for reviewing the code, and to
Victor Stinner for suggesting the idea (originally implemented
in the PyPy project).
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.
Issue #27350: `dict` implementation is changed like PyPy. It is more compact
and preserves insertion order.
_PyDict_Dummy() function has been removed.
Disable test_gdb: python-gdb.py is not updated yet to the new structure of
compact dictionaries (issue #28023).
Patch written by INADA Naoki.
SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off by default. It can
be re-enabled using the "-X showalloccount" option. It now outputs to stderr
instead of stdout.
Victor Stinner
Eric Snow
Mark Shannon
Serhiy Storchaka
Pablo Galindo
Hai Shi
Stefan Pochmann
Brett Cannon
Petr Viktorin
Andy Lester
MojoVampire
Jeroen Demeyer
Victor Stinner
Min ho Kim
Inada Naoki
Jeroen Demeyer
Antoine Pitrou
Steve Dower
penguindustin
Zackery Spytz
Eddie Elizondo
Rémi Lapeyre
Benjamin Peterson
INADA Naoki
Siddhesh Poyarekar
Yury Selivanov
Victor Stinner
Antoine Pitrou
Xiang Zhang
Martin Panter