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).
This change partically reverts
commit ad3252bad9
and the commit fe2978b3b9.
Many third party C extension modules rely on the ability of using
Py_TYPE() to set an object type: "Py_TYPE(obj) = type;" or to set an
object type using: "Py_SIZE(obj) = size;".
Convert Py_REFCNT() and Py_SIZE() macros to static inline functions.
They cannot be used as l-value anymore: use Py_SET_REFCNT() and
Py_SET_SIZE() to set an object reference count and size.
Replace &Py_SIZE(self) with &((PyVarObject*)self)->ob_size
in arraymodule.c.
This change is backward incompatible on purpose, to prepare the C API
for an opaque PyObject structure.
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.
* Add backcompat defines and move non-limited API declaration to cpython/
This partially reverts commit 2ff58a24e8
which added PyObject_CallNoArgs to the 3.9+ stable ABI. This should not
be done; there are enough other call APIs in the stable ABI to choose from.
* Adjust documentation
Mark all newly public functions as added in 3.9.
Add a note about the 3.8 provisional names.
Add notes on public API.
* Put PyObject_CallNoArgs back in the limited API
* Rename PyObject_FastCallDict to PyObject_VectorcallDict
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()
Exclude trashcan mechanism from the limited C API: it requires access to
PyTypeObject and PyThreadState structure fields, whereas these structures
are opaque in the limited C API.
The trashcan mechanism never worked with the limited C API. Move it
from object.h to 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.
Move the following functions from the public C API to the internal C
API:
* _PyDebug_PrintTotalRefs(),
* _Py_PrintReferenceAddresses()
* _Py_PrintReferences()
Filename and line numbers are not needed when Py_REF_DEBUG are not
defined.
The static inline _Py_DECREF() function was introduced by
commit 2aaf0c1204.
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 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.
Release build and debug build are now ABI compatible: the Py_DEBUG
define no longer implies Py_TRACE_REFS define which introduces the
only ABI incompatibility.
A new "./configure --with-trace-refs" build option is now required to
get Py_TRACE_REFS define which adds sys.getobjects() function and
PYTHONDUMPREFS environment variable.
Changes:
* Add ./configure --with-trace-refs
* Py_DEBUG no longer implies Py_TRACE_REFS
Fix the following clang warning:
Include/cpython/pystate.h:217:3: warning: redefinition of
typedef 'PyThreadState' is a C11 feature [-Wtypedef-redefinition]
* Move object.h code surrounded by "#ifndef Py_LIMITED_API"
to a new Include/cpython/object.h header file.
* "typedef struct _typeobject PyTypeObject;" is now always defined
in object.h, but if Py_LIMITED_API is not defined,
Include/cpython/object.h also defines the structure.
* Complete the printfunc comment to mention Py_LIMITED_API define.
* Add _PyObject_ASSERT_FROM() and _PyObject_ASSERT_FAILED_MSG()
macros.
* PyObject_GC_Track() now calls _PyObject_ASSERT_FAILED_MSG(),
instead of Py_FatalError(), if the object is already tracked, to
dump more information on error.
* _PyObject_GC_TRACK() no longer checks if the object is already
tracked at runtime, use an assertion instead for best performances;
PyObject_GC_Track() still checks at runtime.
* pycore_object.h now includes pycore_pystate.h.
* Convert _PyObject_GC_TRACK() and _PyObject_GC_UNTRACK() macros to
inline functions.
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.
_PyTraceMalloc_NewReference() is now called by _Py_NewReference(), so
move its definition to object.h. Moreover, define it even if
Py_LIMITED_API is defined, since _Py_NewReference() is also exposed
even if Py_LIMITED_API is defined.
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>
Victor Stinner
Brandt Bucher
Erlend Egeberg Aasland
Vladimir Matveev
Dong-hee Na
Petr Viktorin
Jimmy Yang
Andy Lester
Hansraj Das
Antoine Pitrou
Jeroen Demeyer
Victor Stinner
Dmitry Marakasov
INADA Naoki
Pablo Galindo