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gh-103509: PEP 697 -- Limited C API for Extending Opaque Types (GH-103511) 

Co-authored-by: Oleg Iarygin <oleg@arhadthedev.net>
Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>
This commit is contained in:
Petr Viktorin 2023-05-04 09:56:53 +02:00 committed by GitHub
parent 35d273825a
commit cd9a56c2b0
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GPG Key ID: 4AEE18F83AFDEB23
30 changed files with 970 additions and 19 deletions
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39
Doc/c-api/object.rst
View File

@ -395,3 +395,42 @@ Object Protocol
returns ``NULL`` if the object cannot be iterated.
.. versionadded:: 3.10
.. c:function:: void *PyObject_GetTypeData(PyObject *o, PyTypeObject *cls)
Get a pointer to subclass-specific data reserved for *cls*.
The object *o* must be an instance of *cls*, and *cls* must have been
created using negative :c:member:`PyType_Spec.basicsize`.
Python does not check this.
On error, set an exception and return ``NULL``.
.. versionadded:: 3.12
.. c:function:: Py_ssize_t PyType_GetTypeDataSize(PyTypeObject *cls)
Return the size of the instance memory space reserved for *cls*, i.e. the size of the
memory :c:func:`PyObject_GetTypeData` returns.
This may be larger than requested using :c:member:`-PyType_Spec.basicsize <PyType_Spec.basicsize>`;
it is safe to use this larger size (e.g. with :c:func:`!memset`).
The type *cls* **must** have been created using
negative :c:member:`PyType_Spec.basicsize`.
Python does not check this.
On error, set an exception and return a negative value.
.. versionadded:: 3.12
.. c:function:: void *PyObject_GetItemData(PyObject *o)
Get a pointer to per-item data for a class with
:const:`Py_TPFLAGS_ITEMS_AT_END`.
On error, set an exception and return ``NULL``.
:py:exc:`TypeError` is raised if *o* does not have
:const:`Py_TPFLAGS_ITEMS_AT_END` set.
.. versionadded:: 3.12

16
Doc/c-api/structures.rst
View File

@ -486,6 +486,22 @@ The following flags can be used with :c:member:`PyMemberDef.flags`:
Emit an ``object.__getattr__`` :ref:`audit event <audit-events>`
before reading.
.. c:macro:: Py_RELATIVE_OFFSET
Indicates that the :c:member:`~PyMemberDef.offset` of this ``PyMemberDef``
entry indicates an offset from the subclass-specific data, rather than
from ``PyObject``.
Can only be used as part of :c:member:`Py_tp_members <PyTypeObject.tp_members>`
:c:type:`slot <PyTypeSlot>` when creating a class using negative
:c:member:`~PyTypeDef.basicsize`.
It is mandatory in that case.
This flag is only used in :c:type:`PyTypeSlot`.
When setting :c:member:`~PyTypeObject.tp_members` during
class creation, Python clears it and sets
:c:member:`PyMemberDef.offset` to the offset from the ``PyObject`` struct.
.. index::
single: READ_RESTRICTED
single: WRITE_RESTRICTED

48
Doc/c-api/type.rst
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@ -353,25 +353,57 @@ The following functions and structs are used to create
Structure defining a type's behavior.
.. c:member:: const char* PyType_Spec.name
.. c:member:: const char* name
Name of the type, used to set :c:member:`PyTypeObject.tp_name`.
.. c:member:: int PyType_Spec.basicsize
.. c:member:: int PyType_Spec.itemsize
.. c:member:: int basicsize
Size of the instance in bytes, used to set
:c:member:`PyTypeObject.tp_basicsize` and
:c:member:`PyTypeObject.tp_itemsize`.
If positive, specifies the size of the instance in bytes.
It is used to set :c:member:`PyTypeObject.tp_basicsize`.
.. c:member:: int PyType_Spec.flags
If zero, specifies that :c:member:`~PyTypeObject.tp_basicsize`
should be inherited.
If negative, the absolute value specifies how much space instances of the
class need *in addition* to the superclass.
Use :c:func:`PyObject_GetTypeData` to get a pointer to subclass-specific
memory reserved this way.
.. versionchanged:: 3.12
Previously, this field could not be negative.
.. c:member:: int itemsize
Size of one element of a variable-size type, in bytes.
Used to set :c:member:`PyTypeObject.tp_itemsize`.
See ``tp_itemsize`` documentation for caveats.
If zero, :c:member:`~PyTypeObject.tp_itemsize` is inherited.
Extending arbitrary variable-sized classes is dangerous,
since some types use a fixed offset for variable-sized memory,
which can then overlap fixed-sized memory used by a subclass.
To help prevent mistakes, inheriting ``itemsize`` is only possible
in the following situations:
- The base is not variable-sized (its
:c:member:`~PyTypeObject.tp_itemsize`).
- The requested :c:member:`PyType_Spec.basicsize` is positive,
suggesting that the memory layout of the base class is known.
- The requested :c:member:`PyType_Spec.basicsize` is zero,
suggesting that the subclass does not access the instance's memory
directly.
- With the :const:`Py_TPFLAGS_ITEMS_AT_END` flag.
.. c:member:: unsigned int flags
Type flags, used to set :c:member:`PyTypeObject.tp_flags`.
If the ``Py_TPFLAGS_HEAPTYPE`` flag is not set,
:c:func:`PyType_FromSpecWithBases` sets it automatically.
.. c:member:: PyType_Slot *PyType_Spec.slots
.. c:member:: PyType_Slot *slots
Array of :c:type:`PyType_Slot` structures.
Terminated by the special slot value ``{0, NULL}``.

20
Doc/c-api/typeobj.rst
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@ -1171,6 +1171,26 @@ and :c:type:`PyType_Type` effectively act as defaults.)
:c:member:`~PyTypeObject.tp_weaklistoffset` field is set in a superclass.
.. data:: Py_TPFLAGS_ITEMS_AT_END
Only usable with variable-size types, i.e. ones with non-zero
:c:member:`~PyObject.tp_itemsize`.
Indicates that the variable-sized portion of an instance of this type is
at the end of the instance's memory area, at an offset of
:c:expr:`Py_TYPE(obj)->tp_basicsize` (which may be different in each
subclass).
When setting this flag, be sure that all superclasses either
use this memory layout, or are not variable-sized.
Python does not check this.
.. versionadded:: 3.12
**Inheritance:**
This flag is inherited.
.. XXX Document more flags here?

2
Doc/data/stable_abi.dat generated
View File

@ -521,6 +521,7 @@ function,PyObject_GetAttrString,3.2,,
function,PyObject_GetBuffer,3.11,,
function,PyObject_GetItem,3.2,,
function,PyObject_GetIter,3.2,,
function,PyObject_GetTypeData,3.12,,
function,PyObject_HasAttr,3.2,,
function,PyObject_HasAttrString,3.2,,
function,PyObject_Hash,3.2,,
@ -675,6 +676,7 @@ function,PyType_GetModuleState,3.10,,
function,PyType_GetName,3.11,,
function,PyType_GetQualName,3.11,,
function,PyType_GetSlot,3.4,,
function,PyType_GetTypeDataSize,3.12,,
function,PyType_IsSubtype,3.2,,
function,PyType_Modified,3.2,,
function,PyType_Ready,3.2,,

15
Doc/whatsnew/3.12.rst
View File

@ -1159,6 +1159,21 @@ New Features
(Contributed by Petr Viktorin in :gh:`101101`.)
* :pep:`697`: Added API for extending types whose instance memory layout is
opaque:
- :c:member:`PyType_Spec.basicsize` can be zero or negative to specify
inheriting or extending the base class size.
- :c:func:`PyObject_GetTypeData` and :c:func:`PyType_GetTypeDataSize`
added to allow access to subclass-specific instance data.
- :const:`Py_TPFLAGS_ITEMS_AT_END` and :c:func:`PyObject_GetItemData`
added to allow safely extending certain variable-sized types, including
:c:var:`PyType_Type`.
- :c:macro:`Py_RELATIVE_OFFSET` added to allow defining
:c:type:`members <PyMemberDef>` in terms of a subclass-specific struct.
(Contributed by Petr Viktorin in :gh:`103509`.)
* Added the new limited C API function :c:func:`PyType_FromMetaclass`,
which generalizes the existing :c:func:`PyType_FromModuleAndSpec` using
an additional metaclass argument.

1
Include/cpython/object.h
View File

@ -553,6 +553,7 @@ Py_DEPRECATED(3.11) typedef int UsingDeprecatedTrashcanMacro;
Py_TRASHCAN_END; \
} while(0);
PyAPI_FUNC(void *) PyObject_GetItemData(PyObject *obj);
PyAPI_FUNC(int) _PyObject_VisitManagedDict(PyObject *obj, visitproc visit, void *arg);
PyAPI_FUNC(void) _PyObject_ClearManagedDict(PyObject *obj);

1
Include/descrobject.h
View File

@ -83,6 +83,7 @@ struct PyMemberDef {
#define Py_READONLY 1
#define Py_AUDIT_READ 2 // Added in 3.10, harmless no-op before that
#define _Py_WRITE_RESTRICTED 4 // Deprecated, no-op. Do not reuse the value.
#define Py_RELATIVE_OFFSET 8
PyAPI_FUNC(PyObject *) PyMember_GetOne(const char *, PyMemberDef *);
PyAPI_FUNC(int) PyMember_SetOne(char *, PyMemberDef *, PyObject *);

5
Include/internal/pycore_object.h
View File

@ -389,11 +389,6 @@ extern PyObject ** _PyObject_ComputedDictPointer(PyObject *);
extern void _PyObject_FreeInstanceAttributes(PyObject *obj);
extern int _PyObject_IsInstanceDictEmpty(PyObject *);
// Access macro to the members which are floating "behind" the object
static inline PyMemberDef* _PyHeapType_GET_MEMBERS(PyHeapTypeObject *etype) {
return (PyMemberDef*)((char*)etype + Py_TYPE(etype)->tp_basicsize);
}
PyAPI_FUNC(PyObject *) _PyObject_LookupSpecial(PyObject *, PyObject *);
/* C function call trampolines to mitigate bad function pointer casts.

5
Include/object.h
View File

@ -355,6 +355,8 @@ PyAPI_FUNC(PyObject *) PyType_GetQualName(PyTypeObject *);
#endif
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000
PyAPI_FUNC(PyObject *) PyType_FromMetaclass(PyTypeObject*, PyObject*, PyType_Spec*, PyObject*);
PyAPI_FUNC(void *) PyObject_GetTypeData(PyObject *obj, PyTypeObject *cls);
PyAPI_FUNC(Py_ssize_t) PyType_GetTypeDataSize(PyTypeObject *cls);
#endif
/* Generic type check */
@ -521,6 +523,9 @@ given type object has a specified feature.
// subject itself (rather than a mapped attribute on it):
#define _Py_TPFLAGS_MATCH_SELF (1UL << 22)
/* Items (ob_size*tp_itemsize) are found at the end of an instance's memory */
#define Py_TPFLAGS_ITEMS_AT_END (1UL << 23)
/* These flags are used to determine if a type is a subclass. */
#define Py_TPFLAGS_LONG_SUBCLASS (1UL << 24)
#define Py_TPFLAGS_LIST_SUBCLASS (1UL << 25)

11
Include/pyport.h
View File

@ -765,4 +765,15 @@ extern char * _getpty(int *, int, mode_t, int);
#undef __bool__
#endif
// Make sure we have maximum alignment, even if the current compiler
// does not support max_align_t. Note that:
// - Autoconf reports alignment of unknown types to 0.
// - 'long double' has maximum alignment on *most* platforms,
// looks like the best we can do for pre-C11 compilers.
// - The value is tested, see test_alignof_max_align_t
#if !defined(ALIGNOF_MAX_ALIGN_T) || ALIGNOF_MAX_ALIGN_T == 0
# undef ALIGNOF_MAX_ALIGN_T
# define ALIGNOF_MAX_ALIGN_T _Alignof(long double)
#endif
#endif /* Py_PYPORT_H */

158
Lib/test/test_capi/test_misc.py
View File

@ -16,11 +16,13 @@ import time
import unittest
import warnings
import weakref
import operator
from test import support
from test.support import MISSING_C_DOCSTRINGS
from test.support import import_helper
from test.support import threading_helper
from test.support import warnings_helper
from test.support import requires_limited_api
from test.support.script_helper import assert_python_failure, assert_python_ok, run_python_until_end
try:
import _posixsubprocess
@ -770,7 +772,6 @@ class CAPITest(unittest.TestCase):
MutableBase.meth = lambda self: 'changed'
self.assertEqual(instance.meth(), 'changed')
def test_pynumber_tobase(self):
from _testcapi import pynumber_tobase
small_number = 123
@ -1072,6 +1073,161 @@ class CAPITest(unittest.TestCase):
self.assertIsNone(d.extra)
@requires_limited_api
class TestHeapTypeRelative(unittest.TestCase):
"""Test API for extending opaque types (PEP 697)"""
@requires_limited_api
def test_heaptype_relative_sizes(self):
# Test subclassing using "relative" basicsize, see PEP 697
def check(extra_base_size, extra_size):
Base, Sub, instance, data_ptr, data_offset, data_size = (
_testcapi.make_sized_heaptypes(
extra_base_size, -extra_size))
# no alignment shenanigans when inheriting directly
if extra_size == 0:
self.assertEqual(Base.__basicsize__, Sub.__basicsize__)
self.assertEqual(data_size, 0)
else:
# The following offsets should be in increasing order:
offsets = [
(0, 'start of object'),
(Base.__basicsize__, 'end of base data'),
(data_offset, 'subclass data'),
(data_offset + extra_size, 'end of requested subcls data'),
(data_offset + data_size, 'end of reserved subcls data'),
(Sub.__basicsize__, 'end of object'),
]
ordered_offsets = sorted(offsets, key=operator.itemgetter(0))
self.assertEqual(
offsets, ordered_offsets,
msg=f'Offsets not in expected order, got: {ordered_offsets}')
# end of reserved subcls data == end of object
self.assertEqual(Sub.__basicsize__, data_offset + data_size)
# we don't reserve (requested + alignment) or more data
self.assertLess(data_size - extra_size,
_testcapi.ALIGNOF_MAX_ALIGN_T)
# The offsets/sizes we calculated should be aligned.
self.assertEqual(data_offset % _testcapi.ALIGNOF_MAX_ALIGN_T, 0)
self.assertEqual(data_size % _testcapi.ALIGNOF_MAX_ALIGN_T, 0)
sizes = sorted({0, 1, 2, 3, 4, 7, 8, 123,
object.__basicsize__,
object.__basicsize__-1,
object.__basicsize__+1})
for extra_base_size in sizes:
for extra_size in sizes:
args = dict(extra_base_size=extra_base_size,
extra_size=extra_size)
with self.subTest(**args):
check(**args)
def test_HeapCCollection(self):
"""Make sure HeapCCollection works properly by itself"""
collection = _testcapi.HeapCCollection(1, 2, 3)
self.assertEqual(list(collection), [1, 2, 3])
def test_heaptype_inherit_itemsize(self):
"""Test HeapCCollection subclasses work properly"""
sizes = sorted({0, 1, 2, 3, 4, 7, 8, 123,
object.__basicsize__,
object.__basicsize__-1,
object.__basicsize__+1})
for extra_size in sizes:
with self.subTest(extra_size=extra_size):
Sub = _testcapi.subclass_var_heaptype(
_testcapi.HeapCCollection, -extra_size, 0, 0)
collection = Sub(1, 2, 3)
collection.set_data_to_3s()
self.assertEqual(list(collection), [1, 2, 3])
mem = collection.get_data()
self.assertGreaterEqual(len(mem), extra_size)
self.assertTrue(set(mem) <= {3}, f'got {mem!r}')
def test_heaptype_invalid_inheritance(self):
with self.assertRaises(SystemError,
msg="Cannot extend variable-size class without "
+ "Py_TPFLAGS_ITEMS_AT_END"):
_testcapi.subclass_heaptype(int, -8, 0)
def test_heaptype_relative_members(self):
"""Test HeapCCollection subclasses work properly"""
sizes = sorted({0, 1, 2, 3, 4, 7, 8, 123,
object.__basicsize__,
object.__basicsize__-1,
object.__basicsize__+1})
for extra_base_size in sizes:
for extra_size in sizes:
for offset in sizes:
with self.subTest(extra_base_size=extra_base_size, extra_size=extra_size, offset=offset):
if offset < extra_size:
Sub = _testcapi.make_heaptype_with_member(
extra_base_size, -extra_size, offset, True)
Base = Sub.mro()[1]
instance = Sub()
self.assertEqual(instance.memb, instance.get_memb())
instance.set_memb(13)
self.assertEqual(instance.memb, instance.get_memb())
self.assertEqual(instance.get_memb(), 13)
instance.memb = 14
self.assertEqual(instance.memb, instance.get_memb())
self.assertEqual(instance.get_memb(), 14)
self.assertGreaterEqual(instance.get_memb_offset(), Base.__basicsize__)
self.assertLess(instance.get_memb_offset(), Sub.__basicsize__)
with self.assertRaises(SystemError):
instance.get_memb_relative()
with self.assertRaises(SystemError):
instance.set_memb_relative(0)
else:
with self.assertRaises(SystemError):
Sub = _testcapi.make_heaptype_with_member(
extra_base_size, -extra_size, offset, True)
with self.assertRaises(SystemError):
Sub = _testcapi.make_heaptype_with_member(
extra_base_size, extra_size, offset, True)
with self.subTest(extra_base_size=extra_base_size, extra_size=extra_size):
with self.assertRaises(SystemError):
Sub = _testcapi.make_heaptype_with_member(
extra_base_size, -extra_size, -1, True)
def test_heaptype_relative_members_errors(self):
with self.assertRaisesRegex(
SystemError,
r"With Py_RELATIVE_OFFSET, basicsize must be negative"):
_testcapi.make_heaptype_with_member(0, 1234, 0, True)
with self.assertRaisesRegex(
SystemError, r"Member offset out of range \(0\.\.-basicsize\)"):
_testcapi.make_heaptype_with_member(0, -8, 1234, True)
with self.assertRaisesRegex(
SystemError, r"Member offset out of range \(0\.\.-basicsize\)"):
_testcapi.make_heaptype_with_member(0, -8, -1, True)
Sub = _testcapi.make_heaptype_with_member(0, -8, 0, True)
instance = Sub()
with self.assertRaisesRegex(
SystemError, r"PyMember_GetOne used with Py_RELATIVE_OFFSET"):
instance.get_memb_relative()
with self.assertRaisesRegex(
SystemError, r"PyMember_SetOne used with Py_RELATIVE_OFFSET"):
instance.set_memb_relative(0)
def test_pyobject_getitemdata_error(self):
"""Test PyObject_GetItemData fails on unsupported types"""
with self.assertRaises(TypeError):
# None is not variable-length
_testcapi.pyobject_getitemdata(None)
with self.assertRaises(TypeError):
# int is variable-length, but doesn't have the
# Py_TPFLAGS_ITEMS_AT_END layout (and flag)
_testcapi.pyobject_getitemdata(0)
class TestPendingCalls(unittest.TestCase):
def pendingcalls_submit(self, l, n):

2
Lib/test/test_stable_abi_ctypes.py generated
View File

@ -529,6 +529,7 @@ SYMBOL_NAMES = (
"PyObject_GetBuffer",
"PyObject_GetItem",
"PyObject_GetIter",
"PyObject_GetTypeData",
"PyObject_HasAttr",
"PyObject_HasAttrString",
"PyObject_Hash",
@ -679,6 +680,7 @@ SYMBOL_NAMES = (
"PyType_GetName",
"PyType_GetQualName",
"PyType_GetSlot",
"PyType_GetTypeDataSize",
"PyType_IsSubtype",
"PyType_Modified",
"PyType_Ready",

5
Misc/NEWS.d/next/C API/2023-04-13-16-54-00.gh-issue-103509.A26Qu8.rst Normal file
View File

@ -0,0 +1,5 @@
Added C API for extending types whose instance memory layout is opaque:
:c:member:`PyType_Spec.basicsize` can now be zero or negative,
:c:func:`PyObject_GetTypeData` can be used to get subclass-specific data,
and :c:macro:`Py_TPFLAGS_ITEMS_AT_END` can be used to safely extend
variable-size objects. See :pep:`697` for details.

9
Misc/stable_abi.toml
View File

@ -2397,3 +2397,12 @@
added = '3.12' # Before 3.12, available in "structmember.h" w/o Py_ prefix
[const.Py_AUDIT_READ]
added = '3.12' # Before 3.12, available in "structmember.h"
[function.PyObject_GetTypeData]
added = '3.12'
[function.PyType_GetTypeDataSize]
added = '3.12'
[const.Py_RELATIVE_OFFSET]
added = '3.12'
[const.Py_TPFLAGS_ITEMS_AT_END]
added = '3.12'

2
Modules/Setup.stdlib.in
View File

@ -169,7 +169,7 @@
@MODULE__XXTESTFUZZ_TRUE@_xxtestfuzz _xxtestfuzz/_xxtestfuzz.c _xxtestfuzz/fuzzer.c
@MODULE__TESTBUFFER_TRUE@_testbuffer _testbuffer.c
@MODULE__TESTINTERNALCAPI_TRUE@_testinternalcapi _testinternalcapi.c
@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c _testcapi/pyos.c _testcapi/immortal.c
@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c _testcapi/pyos.c _testcapi/immortal.c _testcapi/heaptype_relative.c
@MODULE__TESTCLINIC_TRUE@_testclinic _testclinic.c
# Some testing modules MUST be built as shared libraries.

131
Modules/_testcapi/heaptype.c
View File

@ -371,7 +371,6 @@ create_type_from_repeated_slots(PyObject *self, PyObject *variant_obj)
}
static PyObject *
make_immutable_type_with_base(PyObject *self, PyObject *base)
{
@ -399,6 +398,17 @@ make_type_with_base(PyObject *self, PyObject *base)
}
static PyObject *
pyobject_getitemdata(PyObject *self, PyObject *o)
{
void *pointer = PyObject_GetItemData(o);
if (pointer == NULL) {
return NULL;
}
return PyLong_FromVoidPtr(pointer);
}
static PyMethodDef TestMethods[] = {
{"pytype_fromspec_meta", pytype_fromspec_meta, METH_O},
{"test_type_from_ephemeral_spec", test_type_from_ephemeral_spec, METH_NOARGS},
@ -411,6 +421,7 @@ static PyMethodDef TestMethods[] = {
METH_NOARGS},
{"make_immutable_type_with_base", make_immutable_type_with_base, METH_O},
{"make_type_with_base", make_type_with_base, METH_O},
{"pyobject_getitemdata", pyobject_getitemdata, METH_O},
{NULL},
};
@ -987,6 +998,113 @@ static PyType_Spec HeapCTypeSetattr_spec = {
HeapCTypeSetattr_slots
};
PyDoc_STRVAR(HeapCCollection_doc,
"Tuple-like heap type that uses PyObject_GetItemData for items.");
static PyObject*
HeapCCollection_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds)
{
PyObject *self = NULL;
PyObject *result = NULL;
Py_ssize_t size = PyTuple_GET_SIZE(args);
self = subtype->tp_alloc(subtype, size);
if (!self) {
goto finally;
}
PyObject **data = PyObject_GetItemData(self);
if (!data) {
goto finally;
}
for (Py_ssize_t i = 0; i < size; i++) {
data[i] = Py_NewRef(PyTuple_GET_ITEM(args, i));
}
result = self;
self = NULL;
finally:
Py_XDECREF(self);
return result;
}
static Py_ssize_t
HeapCCollection_length(PyVarObject *self)
{
return Py_SIZE(self);
}
static PyObject*
HeapCCollection_item(PyObject *self, Py_ssize_t i)
{
if (i < 0 || i >= Py_SIZE(self)) {
return PyErr_Format(PyExc_IndexError, "index %zd out of range", i);
}
PyObject **data = PyObject_GetItemData(self);
if (!data) {
return NULL;
}
return Py_NewRef(data[i]);
}
static int
HeapCCollection_traverse(PyObject *self, visitproc visit, void *arg)
{
PyObject **data = PyObject_GetItemData(self);
if (!data) {
return -1;
}
for (Py_ssize_t i = 0; i < Py_SIZE(self); i++) {
Py_VISIT(data[i]);
}
return 0;
}
static int
HeapCCollection_clear(PyObject *self)
{
PyObject **data = PyObject_GetItemData(self);
if (!data) {
return -1;
}
Py_ssize_t size = Py_SIZE(self);
Py_SET_SIZE(self, 0);
for (Py_ssize_t i = 0; i < size; i++) {
Py_CLEAR(data[i]);
}
return 0;
}
static void
HeapCCollection_dealloc(PyObject *self)
{
PyTypeObject *tp = Py_TYPE(self);
HeapCCollection_clear(self);
PyObject_GC_UnTrack(self);
tp->tp_free(self);
Py_DECREF(tp);
}
static PyType_Slot HeapCCollection_slots[] = {
{Py_tp_new, HeapCCollection_new},
{Py_sq_length, HeapCCollection_length},
{Py_sq_item, HeapCCollection_item},
{Py_tp_traverse, HeapCCollection_traverse},
{Py_tp_clear, HeapCCollection_clear},
{Py_tp_dealloc, HeapCCollection_dealloc},
{Py_tp_doc, (void *)HeapCCollection_doc},
{0, 0},
};
static PyType_Spec HeapCCollection_spec = {
.name = "_testcapi.HeapCCollection",
.basicsize = sizeof(PyVarObject),
.itemsize = sizeof(PyObject*),
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_ITEMS_AT_END),
.slots = HeapCCollection_slots,
};
int
_PyTestCapi_Init_Heaptype(PyObject *m) {
_testcapimodule = PyModule_GetDef(m);
@ -1110,5 +1228,16 @@ _PyTestCapi_Init_Heaptype(PyObject *m) {
}
PyModule_AddObject(m, "HeapCTypeMetaclassCustomNew", HeapCTypeMetaclassCustomNew);
PyObject *HeapCCollection = PyType_FromMetaclass(
NULL, m, &HeapCCollection_spec, NULL);
if (HeapCCollection == NULL) {
return -1;
}
int rc = PyModule_AddType(m, (PyTypeObject *)HeapCCollection);
Py_DECREF(HeapCCollection);
if (rc < 0) {
return -1;
}
return 0;
}

343
Modules/_testcapi/heaptype_relative.c Normal file
View File

@ -0,0 +1,343 @@
#define Py_LIMITED_API 0x030c0000 // 3.12
#include "parts.h"
#include <stddef.h> // max_align_t
#include <string.h> // memset
#ifdef LIMITED_API_AVAILABLE
static PyType_Slot empty_slots[] = {
{0, NULL},
};
static PyObject *
make_sized_heaptypes(PyObject *module, PyObject *args)
{
PyObject *base = NULL;
PyObject *sub = NULL;
PyObject *instance = NULL;
PyObject *result = NULL;
int extra_base_size, basicsize;
int r = PyArg_ParseTuple(args, "ii", &extra_base_size, &basicsize);
if (!r) {
goto finally;
}
PyType_Spec base_spec = {
.name = "_testcapi.Base",
.basicsize = sizeof(PyObject) + extra_base_size,
.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
.slots = empty_slots,
};
PyType_Spec sub_spec = {
.name = "_testcapi.Sub",
.basicsize = basicsize,
.flags = Py_TPFLAGS_DEFAULT,
.slots = empty_slots,
};
base = PyType_FromMetaclass(NULL, module, &base_spec, NULL);
if (!base) {
goto finally;
}
sub = PyType_FromMetaclass(NULL, module, &sub_spec, base);
if (!sub) {
goto finally;
}
instance = PyObject_CallNoArgs(sub);
if (!instance) {
goto finally;
}
char *data_ptr = PyObject_GetTypeData(instance, (PyTypeObject *)sub);
if (!data_ptr) {
goto finally;
}
Py_ssize_t data_size = PyType_GetTypeDataSize((PyTypeObject *)sub);
if (data_size < 0) {
goto finally;
}
result = Py_BuildValue("OOOKnn", base, sub, instance,
(unsigned long long)data_ptr,
(Py_ssize_t)(data_ptr - (char*)instance),
data_size);
finally:
Py_XDECREF(base);
Py_XDECREF(sub);
Py_XDECREF(instance);
return result;
}
static PyObject *
var_heaptype_set_data_to_3s(
PyObject *self, PyTypeObject *defining_class,
PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
{
void *data_ptr = PyObject_GetTypeData(self, defining_class);
if (!data_ptr) {
return NULL;
}
Py_ssize_t data_size = PyType_GetTypeDataSize(defining_class);
if (data_size < 0) {
return NULL;
}
memset(data_ptr, 3, data_size);
Py_RETURN_NONE;
}
static PyObject *
var_heaptype_get_data(PyObject *self, PyTypeObject *defining_class,
PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
{
void *data_ptr = PyObject_GetTypeData(self, defining_class);
if (!data_ptr) {
return NULL;
}
Py_ssize_t data_size = PyType_GetTypeDataSize(defining_class);
if (data_size < 0) {
return NULL;
}
return PyBytes_FromStringAndSize(data_ptr, data_size);
}
static PyMethodDef var_heaptype_methods[] = {
{"set_data_to_3s", _PyCFunction_CAST(var_heaptype_set_data_to_3s),
METH_METHOD | METH_FASTCALL | METH_KEYWORDS},
{"get_data", _PyCFunction_CAST(var_heaptype_get_data),
METH_METHOD | METH_FASTCALL | METH_KEYWORDS},
{NULL},
};
static PyObject *
subclass_var_heaptype(PyObject *module, PyObject *args)
{
PyObject *result = NULL;
PyObject *base; // borrowed from args
int basicsize, itemsize;
long pfunc;
int r = PyArg_ParseTuple(args, "Oiil", &base, &basicsize, &itemsize, &pfunc);
if (!r) {
goto finally;
}
PyType_Slot slots[] = {
{Py_tp_methods, var_heaptype_methods},
{0, NULL},
};
PyType_Spec sub_spec = {
.name = "_testcapi.Sub",
.basicsize = basicsize,
.itemsize = itemsize,
.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_ITEMS_AT_END,
.slots = slots,
};
result = PyType_FromMetaclass(NULL, module, &sub_spec, base);
finally:
return result;
}
static PyObject *
subclass_heaptype(PyObject *module, PyObject *args)
{
PyObject *result = NULL;
PyObject *base; // borrowed from args
int basicsize, itemsize;
int r = PyArg_ParseTuple(args, "Oii", &base, &basicsize, &itemsize);
if (!r) {
goto finally;
}
PyType_Slot slots[] = {
{Py_tp_methods, var_heaptype_methods},
{0, NULL},
};
PyType_Spec sub_spec = {
.name = "_testcapi.Sub",
.basicsize = basicsize,
.itemsize = itemsize,
.flags = Py_TPFLAGS_DEFAULT,
.slots = slots,
};
result = PyType_FromMetaclass(NULL, module, &sub_spec, base);
finally:
return result;
}
static PyMemberDef *
heaptype_with_member_extract_and_check_memb(PyObject *self)
{
PyMemberDef *def = PyType_GetSlot(Py_TYPE(self), Py_tp_members);
if (!def) {
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_ValueError, "tp_members is NULL");
}
return NULL;
}
if (!def[0].name) {
PyErr_SetString(PyExc_ValueError, "tp_members[0] is NULL");
return NULL;
}
if (def[1].name) {
PyErr_SetString(PyExc_ValueError, "tp_members[1] is not NULL");
return NULL;
}
if (strcmp(def[0].name, "memb")) {
PyErr_SetString(PyExc_ValueError, "tp_members[0] is not for `memb`");
return NULL;
}
if (def[0].flags) {
PyErr_SetString(PyExc_ValueError, "tp_members[0] has flags set");
return NULL;
}
return def;
}
static PyObject *
heaptype_with_member_get_memb(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyMemberDef *def = heaptype_with_member_extract_and_check_memb(self);
return PyMember_GetOne((const char *)self, def);
}
static PyObject *
heaptype_with_member_set_memb(PyObject *self, PyObject *value)
{
PyMemberDef *def = heaptype_with_member_extract_and_check_memb(self);
int r = PyMember_SetOne((char *)self, def, value);
if (r < 0) {
return NULL;
}
Py_RETURN_NONE;
}
static PyObject *
get_memb_offset(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyMemberDef *def = heaptype_with_member_extract_and_check_memb(self);
return PyLong_FromSsize_t(def->offset);
}
static PyObject *
heaptype_with_member_get_memb_relative(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyMemberDef def = {"memb", Py_T_BYTE, sizeof(PyObject), Py_RELATIVE_OFFSET};
return PyMember_GetOne((const char *)self, &def);
}
static PyObject *
heaptype_with_member_set_memb_relative(PyObject *self, PyObject *value)
{
PyMemberDef def = {"memb", Py_T_BYTE, sizeof(PyObject), Py_RELATIVE_OFFSET};
int r = PyMember_SetOne((char *)self, &def, value);
if (r < 0) {
return NULL;
}
Py_RETURN_NONE;
}
static PyMethodDef heaptype_with_member_methods[] = {
{"get_memb", heaptype_with_member_get_memb, METH_NOARGS},
{"set_memb", heaptype_with_member_set_memb, METH_O},
{"get_memb_offset", get_memb_offset, METH_NOARGS},
{"get_memb_relative", heaptype_with_member_get_memb_relative, METH_NOARGS},
{"set_memb_relative", heaptype_with_member_set_memb_relative, METH_O},
{NULL},
};
static PyObject *
make_heaptype_with_member(PyObject *module, PyObject *args)
{
PyObject *base = NULL;
PyObject *result = NULL;
int extra_base_size, basicsize, offset, add_flag;
int r = PyArg_ParseTuple(args, "iiip", &extra_base_size, &basicsize, &offset, &add_flag);
if (!r) {
goto finally;
}
PyType_Spec base_spec = {
.name = "_testcapi.Base",
.basicsize = sizeof(PyObject) + extra_base_size,
.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
.slots = empty_slots,
};
base = PyType_FromMetaclass(NULL, module, &base_spec, NULL);
if (!base) {
goto finally;
}
PyMemberDef members[] = {
{"memb", Py_T_BYTE, offset, add_flag ? Py_RELATIVE_OFFSET : 0},
{0},
};
PyType_Slot slots[] = {
{Py_tp_members, members},
{Py_tp_methods, heaptype_with_member_methods},
{0, NULL},
};
PyType_Spec sub_spec = {
.name = "_testcapi.Sub",
.basicsize = basicsize,
.flags = Py_TPFLAGS_DEFAULT,
.slots = slots,
};
result = PyType_FromMetaclass(NULL, module, &sub_spec, base);
finally:
Py_XDECREF(base);
return result;
}
static PyObject *
test_alignof_max_align_t(PyObject *module, PyObject *Py_UNUSED(ignored))
{
// We define ALIGNOF_MAX_ALIGN_T even if the compiler doesn't support
// max_align_t. Double-check that it's correct.
assert(ALIGNOF_MAX_ALIGN_T > 0);
assert(ALIGNOF_MAX_ALIGN_T >= _Alignof(long long));
assert(ALIGNOF_MAX_ALIGN_T >= _Alignof(long double));
assert(ALIGNOF_MAX_ALIGN_T >= _Alignof(void*));
assert(ALIGNOF_MAX_ALIGN_T >= _Alignof(void (*)(void)));
// Ensure it's a power of two
assert((ALIGNOF_MAX_ALIGN_T & (ALIGNOF_MAX_ALIGN_T - 1)) == 0);
Py_RETURN_NONE;
}
static PyMethodDef TestMethods[] = {
{"make_sized_heaptypes", make_sized_heaptypes, METH_VARARGS},
{"subclass_var_heaptype", subclass_var_heaptype, METH_VARARGS},
{"subclass_heaptype", subclass_heaptype, METH_VARARGS},
{"make_heaptype_with_member", make_heaptype_with_member, METH_VARARGS},
{"test_alignof_max_align_t", test_alignof_max_align_t, METH_NOARGS},
{NULL},
};
int
_PyTestCapi_Init_HeaptypeRelative(PyObject *m) {
if (PyModule_AddFunctions(m, TestMethods) < 0) {
return -1;
}
if (PyModule_AddIntMacro(m, ALIGNOF_MAX_ALIGN_T) < 0) {
return -1;
}
return 0;
}
#endif // LIMITED_API_AVAILABLE

1
Modules/_testcapi/parts.h
View File

@ -43,6 +43,7 @@ int _PyTestCapi_Init_Immortal(PyObject *module);
#ifdef LIMITED_API_AVAILABLE
int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
int _PyTestCapi_Init_HeaptypeRelative(PyObject *module);
#endif // LIMITED_API_AVAILABLE
#endif

3
Modules/_testcapimodule.c
View File

@ -4324,6 +4324,9 @@ PyInit__testcapi(void)
if (_PyTestCapi_Init_VectorcallLimited(m) < 0) {
return NULL;
}
if (_PyTestCapi_Init_HeaptypeRelative(m) < 0) {
return NULL;
}
#endif
PyState_AddModule(m, &_testcapimodule);

6
Objects/descrobject.c
View File

@ -978,6 +978,12 @@ PyDescr_NewMember(PyTypeObject *type, PyMemberDef *member)
{
PyMemberDescrObject *descr;
if (member->flags & Py_RELATIVE_OFFSET) {
PyErr_SetString(
PyExc_SystemError,
"PyDescr_NewMember used with Py_RELATIVE_OFFSET");
return NULL;
}
descr = (PyMemberDescrObject *)descr_new(&PyMemberDescr_Type,
type, member->name);
if (descr != NULL)

107
Objects/typeobject.c
View File

@ -18,6 +18,7 @@
#include "structmember.h" // PyMemberDef
#include <ctype.h>
#include <stddef.h> // ptrdiff_t
/*[clinic input]
class type "PyTypeObject *" "&PyType_Type"
@ -1686,6 +1687,12 @@ PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
/* Helpers for subtyping */
static inline PyMemberDef *
_PyHeapType_GET_MEMBERS(PyHeapTypeObject* type)
{
return PyObject_GetItemData((PyObject *)type);
}
static int
traverse_slots(PyTypeObject *type, PyObject *self, visitproc visit, void *arg)
{
@ -3873,6 +3880,15 @@ static const PySlot_Offset pyslot_offsets[] = {
#include "typeslots.inc"
};
/* Align up to the nearest multiple of alignof(max_align_t)
* (like _Py_ALIGN_UP, but for a size rather than pointer)
*/
static Py_ssize_t
_align_up(Py_ssize_t size)
{
return (size + ALIGNOF_MAX_ALIGN_T - 1) & ~(ALIGNOF_MAX_ALIGN_T - 1);
}
/* Given a PyType_FromMetaclass `bases` argument (NULL, type, or tuple of
* types), return a tuple of types.
*/
@ -4013,6 +4029,20 @@ _PyType_FromMetaclass_impl(
assert(memb->flags == READONLY);
vectorcalloffset = memb->offset;
}
if (memb->flags & Py_RELATIVE_OFFSET) {
if (spec->basicsize > 0) {
PyErr_SetString(
PyExc_SystemError,
"With Py_RELATIVE_OFFSET, basicsize must be negative.");
goto finally;
}
if (memb->offset < 0 || memb->offset >= -spec->basicsize) {
PyErr_SetString(
PyExc_SystemError,
"Member offset out of range (0..-basicsize)");
goto finally;
}
}
}
break;
case Py_tp_doc:
@ -4154,6 +4184,32 @@ _PyType_FromMetaclass_impl(
// here we just check its work
assert(_PyType_HasFeature(base, Py_TPFLAGS_BASETYPE));
/* Calculate sizes */
Py_ssize_t basicsize = spec->basicsize;
Py_ssize_t type_data_offset = spec->basicsize;
if (basicsize == 0) {
/* Inherit */
basicsize = base->tp_basicsize;
}
else if (basicsize < 0) {
/* Extend */
type_data_offset = _align_up(base->tp_basicsize);
basicsize = type_data_offset + _align_up(-spec->basicsize);
/* Inheriting variable-sized types is limited */
if (base->tp_itemsize
&& !((base->tp_flags | spec->flags) & Py_TPFLAGS_ITEMS_AT_END))
{
PyErr_SetString(
PyExc_SystemError,
"Cannot extend variable-size class without Py_TPFLAGS_ITEMS_AT_END.");
goto finally;
}
}
Py_ssize_t itemsize = spec->itemsize;
/* Allocate the new type
*
* Between here and PyType_Ready, we should limit:
@ -4201,8 +4257,8 @@ _PyType_FromMetaclass_impl(
/* Copy the sizes */
type->tp_basicsize = spec->basicsize;
type->tp_itemsize = spec->itemsize;
type->tp_basicsize = basicsize;
type->tp_itemsize = itemsize;
/* Copy all the ordinary slots */
@ -4219,6 +4275,16 @@ _PyType_FromMetaclass_impl(
size_t len = Py_TYPE(type)->tp_itemsize * nmembers;
memcpy(_PyHeapType_GET_MEMBERS(res), slot->pfunc, len);
type->tp_members = _PyHeapType_GET_MEMBERS(res);
PyMemberDef *memb;
Py_ssize_t i;
for (memb = _PyHeapType_GET_MEMBERS(res), i = nmembers;
i > 0; ++memb, --i)
{
if (memb->flags & Py_RELATIVE_OFFSET) {
memb->flags &= ~Py_RELATIVE_OFFSET;
memb->offset += type_data_offset;
}
}
}
break;
default:
@ -4227,6 +4293,7 @@ _PyType_FromMetaclass_impl(
PySlot_Offset slotoffsets = pyslot_offsets[slot->slot];
short slot_offset = slotoffsets.slot_offset;
if (slotoffsets.subslot_offset == -1) {
/* Set a slot in the main PyTypeObject */
*(void**)((char*)res_start + slot_offset) = slot->pfunc;
}
else {
@ -4461,6 +4528,34 @@ PyType_GetModuleByDef(PyTypeObject *type, PyModuleDef *def)
return NULL;
}
void *
PyObject_GetTypeData(PyObject *obj, PyTypeObject *cls)
{
assert(PyObject_TypeCheck(obj, cls));
return (char *)obj + _align_up(cls->tp_base->tp_basicsize);
}
Py_ssize_t
PyType_GetTypeDataSize(PyTypeObject *cls)
{
ptrdiff_t result = cls->tp_basicsize - _align_up(cls->tp_base->tp_basicsize);
if (result < 0) {
return 0;
}
return result;
}
void *
PyObject_GetItemData(PyObject *obj)
{
if (!PyType_HasFeature(Py_TYPE(obj), Py_TPFLAGS_ITEMS_AT_END)) {
PyErr_Format(PyExc_TypeError,
"type '%s' does not have Py_TPFLAGS_ITEMS_AT_END",
Py_TYPE(obj)->tp_name);
return NULL;
}
return (char *)obj + Py_TYPE(obj)->tp_basicsize;
}
/* Internal API to look for a name through the MRO, bypassing the method cache.
This returns a borrowed reference, and might set an exception.
@ -5158,7 +5253,8 @@ PyTypeObject PyType_Type = {
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TYPE_SUBCLASS |
Py_TPFLAGS_HAVE_VECTORCALL, /* tp_flags */
Py_TPFLAGS_HAVE_VECTORCALL |
Py_TPFLAGS_ITEMS_AT_END, /* tp_flags */
type_doc, /* tp_doc */
(traverseproc)type_traverse, /* tp_traverse */
(inquiry)type_clear, /* tp_clear */
@ -6572,9 +6668,14 @@ inherit_special(PyTypeObject *type, PyTypeObject *base)
else if (PyType_IsSubtype(base, &PyDict_Type)) {
type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
}
/* Setup some inheritable flags */
if (PyType_HasFeature(base, _Py_TPFLAGS_MATCH_SELF)) {
type->tp_flags |= _Py_TPFLAGS_MATCH_SELF;
}
if (PyType_HasFeature(base, Py_TPFLAGS_ITEMS_AT_END)) {
type->tp_flags |= Py_TPFLAGS_ITEMS_AT_END;
}
}
static int

2
PC/pyconfig.h
View File

@ -330,6 +330,7 @@ Py_NO_ENABLE_SHARED to find out. Also support MS_NO_COREDLL for b/w compat */
# define SIZEOF_HKEY 8
# define SIZEOF_SIZE_T 8
# define ALIGNOF_SIZE_T 8
# define ALIGNOF_MAX_ALIGN_T 8
/* configure.ac defines HAVE_LARGEFILE_SUPPORT iff
sizeof(off_t) > sizeof(long), and sizeof(long long) >= sizeof(off_t).
On Win64 the second condition is not true, but if fpos_t replaces off_t
@ -351,6 +352,7 @@ Py_NO_ENABLE_SHARED to find out. Also support MS_NO_COREDLL for b/w compat */
# else
# define SIZEOF_TIME_T 4
# endif
# define ALIGNOF_MAX_ALIGN_T 8
#endif
#ifdef _DEBUG

2
PC/python3dll.c generated
View File

@ -467,6 +467,7 @@ EXPORT_FUNC(PyObject_GetAttrString)
EXPORT_FUNC(PyObject_GetBuffer)
EXPORT_FUNC(PyObject_GetItem)
EXPORT_FUNC(PyObject_GetIter)
EXPORT_FUNC(PyObject_GetTypeData)
EXPORT_FUNC(PyObject_HasAttr)
EXPORT_FUNC(PyObject_HasAttrString)
EXPORT_FUNC(PyObject_Hash)
@ -618,6 +619,7 @@ EXPORT_FUNC(PyType_GetModuleState)
EXPORT_FUNC(PyType_GetName)
EXPORT_FUNC(PyType_GetQualName)
EXPORT_FUNC(PyType_GetSlot)
EXPORT_FUNC(PyType_GetTypeDataSize)
EXPORT_FUNC(PyType_IsSubtype)
EXPORT_FUNC(PyType_Modified)
EXPORT_FUNC(PyType_Ready)

1
PCbuild/_testcapi.vcxproj
View File

@ -98,6 +98,7 @@
<ClCompile Include="..\Modules\_testcapi\vectorcall.c" />
<ClCompile Include="..\Modules\_testcapi\vectorcall_limited.c" />
<ClCompile Include="..\Modules\_testcapi\heaptype.c" />
<ClCompile Include="..\Modules\_testcapi\heaptype_relative.c" />
<ClCompile Include="..\Modules\_testcapi\unicode.c" />
<ClCompile Include="..\Modules\_testcapi\pytime.c" />
<ClCompile Include="..\Modules\_testcapi\datetime.c" />

3
PCbuild/_testcapi.vcxproj.filters
View File

@ -24,6 +24,9 @@
<ClCompile Include="..\Modules\_testcapi\heaptype.c">
<Filter>Source Files</Filter>
</ClCompile>
<ClCompile Include="..\Modules\_testcapi\heaptype_relative.c">
<Filter>Source Files</Filter>
</ClCompile>
<ClCompile Include="..\Modules\_testcapi\unicode.c">
<Filter>Source Files</Filter>
</ClCompile>

12
Python/structmember.c
View File

@ -8,6 +8,12 @@ PyObject *
PyMember_GetOne(const char *obj_addr, PyMemberDef *l)
{
PyObject *v;
if (l->flags & Py_RELATIVE_OFFSET) {
PyErr_SetString(
PyExc_SystemError,
"PyMember_GetOne used with Py_RELATIVE_OFFSET");
return NULL;
}
const char* addr = obj_addr + l->offset;
switch (l->type) {
@ -103,6 +109,12 @@ int
PyMember_SetOne(char *addr, PyMemberDef *l, PyObject *v)
{
PyObject *oldv;
if (l->flags & Py_RELATIVE_OFFSET) {
PyErr_SetString(
PyExc_SystemError,
"PyMember_SetOne used with Py_RELATIVE_OFFSET");
return -1;
}
addr += l->offset;

35
configure generated vendored
View File

@ -10729,6 +10729,41 @@ cat >>confdefs.h <<_ACEOF
_ACEOF
# The cast to long int works around a bug in the HP C Compiler,
# see AC_CHECK_SIZEOF for more information.
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking alignment of max_align_t" >&5
$as_echo_n "checking alignment of max_align_t... " >&6; }
if ${ac_cv_alignof_max_align_t+:} false; then :
$as_echo_n "(cached) " >&6
else
if ac_fn_c_compute_int "$LINENO" "(long int) offsetof (ac__type_alignof_, y)" "ac_cv_alignof_max_align_t" "$ac_includes_default
#ifndef offsetof
# define offsetof(type, member) ((char *) &((type *) 0)->member - (char *) 0)
#endif
typedef struct { char x; max_align_t y; } ac__type_alignof_;"; then :
else
if test "$ac_cv_type_max_align_t" = yes; then
{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
as_fn_error 77 "cannot compute alignment of max_align_t
See \`config.log' for more details" "$LINENO" 5; }
else
ac_cv_alignof_max_align_t=0
fi
fi
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_alignof_max_align_t" >&5
$as_echo "$ac_cv_alignof_max_align_t" >&6; }
cat >>confdefs.h <<_ACEOF
#define ALIGNOF_MAX_ALIGN_T $ac_cv_alignof_max_align_t
_ACEOF
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for long double" >&5

1
configure.ac
View File

@ -2921,6 +2921,7 @@ AC_CHECK_SIZEOF(size_t, 4)
AC_CHECK_ALIGNOF(size_t)
AC_CHECK_SIZEOF(pid_t, 4)
AC_CHECK_SIZEOF(uintptr_t)
AC_CHECK_ALIGNOF(max_align_t)
AC_TYPE_LONG_DOUBLE
AC_CHECK_SIZEOF(long double, 16)

3
pyconfig.h.in
View File

@ -19,6 +19,9 @@
/* The normal alignment of `long', in bytes. */
#undef ALIGNOF_LONG
/* The normal alignment of `max_align_t', in bytes. */
#undef ALIGNOF_MAX_ALIGN_T
/* The normal alignment of `size_t', in bytes. */
#undef ALIGNOF_SIZE_T