-
-
Notifications
You must be signed in to change notification settings - Fork 34.2k
Expand file tree
/
Copy pathpycore_object.h
More file actions
1041 lines (926 loc) · 33.2 KB
/
pycore_object.h
File metadata and controls
1041 lines (926 loc) · 33.2 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#ifndef Py_INTERNAL_OBJECT_H
#define Py_INTERNAL_OBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
#include "pycore_emscripten_trampoline.h" // _PyCFunction_TrampolineCall()
#include "pycore_gc.h" // _PyObject_GC_TRACK()
#include "pycore_pyatomic_ft_wrappers.h" // FT_ATOMIC_LOAD_PTR_ACQUIRE()
#include "pycore_pystate.h" // _PyInterpreterState_GET()
#include "pycore_runtime.h" // _PyRuntime
#include "pycore_typeobject.h" // _PyStaticType_GetState()
#include "pycore_uniqueid.h" // _PyObject_ThreadIncrefSlow()
#include <stdbool.h> // bool
// This value is added to `ob_ref_shared` for objects that use deferred
// reference counting so that they are not immediately deallocated when the
// non-deferred reference count drops to zero.
//
// The value is half the maximum shared refcount because the low two bits of
// `ob_ref_shared` are used for flags.
#define _Py_REF_DEFERRED (PY_SSIZE_T_MAX / 8)
/* For backwards compatibility -- Do not use this */
#define _Py_IsImmortalLoose(op) _Py_IsImmortal
/* Check if an object is consistent. For example, ensure that the reference
counter is greater than or equal to 1, and ensure that ob_type is not NULL.
Call _PyObject_AssertFailed() if the object is inconsistent.
If check_content is zero, only check header fields: reduce the overhead.
The function always return 1. The return value is just here to be able to
write:
assert(_PyObject_CheckConsistency(obj, 1)); */
extern int _PyObject_CheckConsistency(PyObject *op, int check_content);
extern void _PyDebugAllocatorStats(FILE *out, const char *block_name,
int num_blocks, size_t sizeof_block);
extern void _PyObject_DebugTypeStats(FILE *out);
#ifdef Py_TRACE_REFS
// Forget a reference registered by _Py_NewReference(). Function called by
// _Py_Dealloc().
//
// On a free list, the function can be used before modifying an object to
// remove the object from traced objects. Then _Py_NewReference() or
// _Py_NewReferenceNoTotal() should be called again on the object to trace
// it again.
extern void _Py_ForgetReference(PyObject *);
#endif
// Export for shared _testinternalcapi extension
PyAPI_FUNC(int) _PyObject_IsFreed(PyObject *);
/* We need to maintain an internal copy of Py{Var}Object_HEAD_INIT to avoid
designated initializer conflicts in C++20. If we use the definition in
object.h, we will be mixing designated and non-designated initializers in
pycore objects which is forbiddent in C++20. However, if we then use
designated initializers in object.h then Extensions without designated break.
Furthermore, we can't use designated initializers in Extensions since these
are not supported pre-C++20. Thus, keeping an internal copy here is the most
backwards compatible solution */
#if defined(Py_GIL_DISABLED)
#define _PyObject_HEAD_INIT(type) \
{ \
.ob_ref_local = _Py_IMMORTAL_REFCNT_LOCAL, \
.ob_flags = _Py_STATICALLY_ALLOCATED_FLAG, \
.ob_gc_bits = _PyGC_BITS_DEFERRED, \
.ob_type = (type) \
}
#else
#if SIZEOF_VOID_P > 4
#define _PyObject_HEAD_INIT(type) \
{ \
.ob_refcnt = _Py_IMMORTAL_INITIAL_REFCNT, \
.ob_flags = _Py_STATIC_FLAG_BITS, \
.ob_type = (type) \
}
#else
#define _PyObject_HEAD_INIT(type) \
{ \
.ob_refcnt = _Py_STATIC_IMMORTAL_INITIAL_REFCNT, \
.ob_type = (type) \
}
#endif
#endif
#define _PyVarObject_HEAD_INIT(type, size) \
{ \
.ob_base = _PyObject_HEAD_INIT(type), \
.ob_size = size \
}
PyAPI_FUNC(void) _Py_NO_RETURN _Py_FatalRefcountErrorFunc(
const char *func,
const char *message);
#define _Py_FatalRefcountError(message) \
_Py_FatalRefcountErrorFunc(__func__, (message))
#define _PyReftracerTrack(obj, operation) \
do { \
struct _reftracer_runtime_state *tracer = &_PyRuntime.ref_tracer; \
if (tracer->tracer_func != NULL) { \
void *data = tracer->tracer_data; \
tracer->tracer_func((obj), (operation), data); \
} \
} while(0)
#ifdef Py_REF_DEBUG
/* The symbol is only exposed in the API for the sake of extensions
built against the pre-3.12 stable ABI. */
PyAPI_DATA(Py_ssize_t) _Py_RefTotal;
extern void _Py_AddRefTotal(PyThreadState *, Py_ssize_t);
extern PyAPI_FUNC(void) _Py_IncRefTotal(PyThreadState *);
extern PyAPI_FUNC(void) _Py_DecRefTotal(PyThreadState *);
# define _Py_DEC_REFTOTAL(interp) \
interp->object_state.reftotal--
#endif
// Increment reference count by n
static inline void _Py_RefcntAdd(PyObject* op, Py_ssize_t n)
{
if (_Py_IsImmortal(op)) {
_Py_INCREF_IMMORTAL_STAT_INC();
return;
}
#ifndef Py_GIL_DISABLED
Py_ssize_t refcnt = _Py_REFCNT(op);
Py_ssize_t new_refcnt = refcnt + n;
if (new_refcnt >= (Py_ssize_t)_Py_IMMORTAL_MINIMUM_REFCNT) {
new_refcnt = _Py_IMMORTAL_INITIAL_REFCNT;
}
# if SIZEOF_VOID_P > 4
op->ob_refcnt = (PY_UINT32_T)new_refcnt;
# else
op->ob_refcnt = new_refcnt;
# endif
# ifdef Py_REF_DEBUG
_Py_AddRefTotal(_PyThreadState_GET(), new_refcnt - refcnt);
# endif
#else
if (_Py_IsOwnedByCurrentThread(op)) {
uint32_t local = op->ob_ref_local;
Py_ssize_t refcnt = (Py_ssize_t)local + n;
# if PY_SSIZE_T_MAX > UINT32_MAX
if (refcnt > (Py_ssize_t)UINT32_MAX) {
// Make the object immortal if the 32-bit local reference count
// would overflow.
refcnt = _Py_IMMORTAL_REFCNT_LOCAL;
}
# endif
_Py_atomic_store_uint32_relaxed(&op->ob_ref_local, (uint32_t)refcnt);
}
else {
_Py_atomic_add_ssize(&op->ob_ref_shared, (n << _Py_REF_SHARED_SHIFT));
}
# ifdef Py_REF_DEBUG
_Py_AddRefTotal(_PyThreadState_GET(), n);
# endif
#endif
// Although the ref count was increased by `n` (which may be greater than 1)
// it is only a single increment (i.e. addition) operation, so only 1 refcnt
// increment operation is counted.
_Py_INCREF_STAT_INC();
}
#define _Py_RefcntAdd(op, n) _Py_RefcntAdd(_PyObject_CAST(op), n)
// Checks if an object has a single, unique reference. If the caller holds a
// unique reference, it may be able to safely modify the object in-place.
static inline int
_PyObject_IsUniquelyReferenced(PyObject *ob)
{
#if !defined(Py_GIL_DISABLED)
return Py_REFCNT(ob) == 1;
#else
// NOTE: the entire ob_ref_shared field must be zero, including flags, to
// ensure that other threads cannot concurrently create new references to
// this object.
return (_Py_IsOwnedByCurrentThread(ob) &&
_Py_atomic_load_uint32_relaxed(&ob->ob_ref_local) == 1 &&
_Py_atomic_load_ssize_relaxed(&ob->ob_ref_shared) == 0);
#endif
}
PyAPI_FUNC(void) _Py_SetImmortal(PyObject *op);
PyAPI_FUNC(void) _Py_SetImmortalUntracked(PyObject *op);
// Makes an immortal object mortal again with the specified refcnt. Should only
// be used during runtime finalization.
static inline void _Py_SetMortal(PyObject *op, short refcnt)
{
if (op) {
assert(_Py_IsImmortal(op));
#ifdef Py_GIL_DISABLED
op->ob_tid = _Py_UNOWNED_TID;
op->ob_ref_local = 0;
op->ob_ref_shared = _Py_REF_SHARED(refcnt, _Py_REF_MERGED);
#else
op->ob_refcnt = refcnt;
#endif
}
}
/* _Py_ClearImmortal() should only be used during runtime finalization. */
static inline void _Py_ClearImmortal(PyObject *op)
{
if (op) {
_Py_SetMortal(op, 1);
Py_DECREF(op);
}
}
#define _Py_ClearImmortal(op) \
do { \
_Py_ClearImmortal(_PyObject_CAST(op)); \
op = NULL; \
} while (0)
#if !defined(Py_GIL_DISABLED)
static inline void
_Py_DECREF_SPECIALIZED(PyObject *op, const destructor destruct)
{
if (_Py_IsImmortal(op)) {
_Py_DECREF_IMMORTAL_STAT_INC();
return;
}
_Py_DECREF_STAT_INC();
#ifdef Py_REF_DEBUG
_Py_DEC_REFTOTAL(PyInterpreterState_Get());
#endif
if (--op->ob_refcnt != 0) {
assert(op->ob_refcnt > 0);
}
else {
#ifdef Py_TRACE_REFS
_Py_ForgetReference(op);
#endif
_PyReftracerTrack(op, PyRefTracer_DESTROY);
destruct(op);
}
}
#else
// TODO: implement Py_DECREF specializations for Py_GIL_DISABLED build
static inline void
_Py_DECREF_SPECIALIZED(PyObject *op, const destructor destruct)
{
Py_DECREF(op);
}
static inline int
_Py_REF_IS_MERGED(Py_ssize_t ob_ref_shared)
{
return (ob_ref_shared & _Py_REF_SHARED_FLAG_MASK) == _Py_REF_MERGED;
}
static inline int
_Py_REF_IS_QUEUED(Py_ssize_t ob_ref_shared)
{
return (ob_ref_shared & _Py_REF_SHARED_FLAG_MASK) == _Py_REF_QUEUED;
}
// Merge the local and shared reference count fields and add `extra` to the
// refcount when merging.
Py_ssize_t _Py_ExplicitMergeRefcount(PyObject *op, Py_ssize_t extra);
#endif // !defined(Py_GIL_DISABLED)
#ifdef Py_REF_DEBUG
# undef _Py_DEC_REFTOTAL
#endif
extern int _PyType_CheckConsistency(PyTypeObject *type);
extern int _PyDict_CheckConsistency(PyObject *mp, int check_content);
// Fast inlined version of PyType_HasFeature()
static inline int
_PyType_HasFeature(PyTypeObject *type, unsigned long feature) {
return ((type->tp_flags) & feature) != 0;
}
extern void _PyType_InitCache(PyInterpreterState *interp);
extern PyStatus _PyObject_InitState(PyInterpreterState *interp);
extern void _PyObject_FiniState(PyInterpreterState *interp);
extern bool _PyRefchain_IsTraced(PyInterpreterState *interp, PyObject *obj);
// Macros used for per-thread reference counting in the free threading build.
// They resolve to normal Py_INCREF/DECREF calls in the default build.
//
// The macros are used for only a few references that would otherwise cause
// scaling bottlenecks in the free threading build:
// - The reference from an object to `ob_type`.
// - The reference from a function to `func_code`.
// - The reference from a function to `func_globals` and `func_builtins`.
//
// It's safe, but not performant or necessary, to use these macros for other
// references to code, type, or dict objects. It's also safe to mix their
// usage with normal Py_INCREF/DECREF calls.
//
// See also Include/internal/pycore_dict.h for _Py_INCREF_DICT/_Py_DECREF_DICT.
#ifndef Py_GIL_DISABLED
# define _Py_INCREF_TYPE Py_INCREF
# define _Py_DECREF_TYPE Py_DECREF
# define _Py_INCREF_CODE Py_INCREF
# define _Py_DECREF_CODE Py_DECREF
#else
static inline void
_Py_THREAD_INCREF_OBJECT(PyObject *obj, Py_ssize_t unique_id)
{
_PyThreadStateImpl *tstate = (_PyThreadStateImpl *)_PyThreadState_GET();
// The table index is `unique_id - 1` because 0 is not a valid unique id.
// Unsigned comparison so that `idx=-1` is handled by the "else".
size_t idx = (size_t)(unique_id - 1);
if (idx < (size_t)tstate->refcounts.size) {
# ifdef Py_REF_DEBUG
_Py_INCREF_IncRefTotal();
# endif
_Py_INCREF_STAT_INC();
tstate->refcounts.values[idx]++;
}
else {
// The slow path resizes the per-thread refcount array if necessary.
// It handles the unique_id=0 case to keep the inlinable function smaller.
_PyObject_ThreadIncrefSlow(obj, idx);
}
}
static inline void
_Py_INCREF_TYPE(PyTypeObject *type)
{
if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
assert(_Py_IsImmortal(type));
_Py_INCREF_IMMORTAL_STAT_INC();
return;
}
// gh-122974: GCC 11 warns about the access to PyHeapTypeObject fields when
// _Py_INCREF_TYPE() is called on a statically allocated type. The
// _PyType_HasFeature check above ensures that the type is a heap type.
#if defined(__GNUC__) && __GNUC__ >= 11
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Warray-bounds"
#endif
_Py_THREAD_INCREF_OBJECT((PyObject *)type, ((PyHeapTypeObject *)type)->unique_id);
#if defined(__GNUC__) && __GNUC__ >= 11
# pragma GCC diagnostic pop
#endif
}
static inline void
_Py_INCREF_CODE(PyCodeObject *co)
{
_Py_THREAD_INCREF_OBJECT((PyObject *)co, co->_co_unique_id);
}
static inline void
_Py_THREAD_DECREF_OBJECT(PyObject *obj, Py_ssize_t unique_id)
{
_PyThreadStateImpl *tstate = (_PyThreadStateImpl *)_PyThreadState_GET();
// The table index is `unique_id - 1` because 0 is not a valid unique id.
// Unsigned comparison so that `idx=-1` is handled by the "else".
size_t idx = (size_t)(unique_id - 1);
if (idx < (size_t)tstate->refcounts.size) {
# ifdef Py_REF_DEBUG
_Py_DECREF_DecRefTotal();
# endif
_Py_DECREF_STAT_INC();
tstate->refcounts.values[idx]--;
}
else {
// Directly decref the object if the id is not assigned or if
// per-thread refcounting has been disabled on this object.
Py_DECREF(obj);
}
}
static inline void
_Py_DECREF_TYPE(PyTypeObject *type)
{
if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
assert(_Py_IsImmortal(type));
_Py_DECREF_IMMORTAL_STAT_INC();
return;
}
PyHeapTypeObject *ht = (PyHeapTypeObject *)type;
_Py_THREAD_DECREF_OBJECT((PyObject *)type, ht->unique_id);
}
static inline void
_Py_DECREF_CODE(PyCodeObject *co)
{
_Py_THREAD_DECREF_OBJECT((PyObject *)co, co->_co_unique_id);
}
#endif
#ifndef Py_GIL_DISABLED
#ifdef Py_REF_DEBUG
static inline void Py_DECREF_MORTAL(const char *filename, int lineno, PyObject *op)
{
if (op->ob_refcnt <= 0) {
_Py_NegativeRefcount(filename, lineno, op);
}
_Py_DECREF_STAT_INC();
assert(!_Py_IsStaticImmortal(op));
if (!_Py_IsImmortal(op)) {
_Py_DECREF_DecRefTotal();
}
if (--op->ob_refcnt == 0) {
_Py_Dealloc(op);
}
}
#define Py_DECREF_MORTAL(op) Py_DECREF_MORTAL(__FILE__, __LINE__, _PyObject_CAST(op))
static inline void _Py_DECREF_MORTAL_SPECIALIZED(const char *filename, int lineno, PyObject *op, destructor destruct)
{
if (op->ob_refcnt <= 0) {
_Py_NegativeRefcount(filename, lineno, op);
}
_Py_DECREF_STAT_INC();
assert(!_Py_IsStaticImmortal(op));
if (!_Py_IsImmortal(op)) {
_Py_DECREF_DecRefTotal();
}
if (--op->ob_refcnt == 0) {
#ifdef Py_TRACE_REFS
_Py_ForgetReference(op);
#endif
_PyReftracerTrack(op, PyRefTracer_DESTROY);
destruct(op);
}
}
#define Py_DECREF_MORTAL_SPECIALIZED(op, destruct) _Py_DECREF_MORTAL_SPECIALIZED(__FILE__, __LINE__, op, destruct)
#else
static inline void Py_DECREF_MORTAL(PyObject *op)
{
assert(!_Py_IsStaticImmortal(op));
_Py_DECREF_STAT_INC();
if (--op->ob_refcnt == 0) {
_Py_Dealloc(op);
}
}
#define Py_DECREF_MORTAL(op) Py_DECREF_MORTAL(_PyObject_CAST(op))
static inline void Py_DECREF_MORTAL_SPECIALIZED(PyObject *op, destructor destruct)
{
assert(!_Py_IsStaticImmortal(op));
_Py_DECREF_STAT_INC();
if (--op->ob_refcnt == 0) {
_PyReftracerTrack(op, PyRefTracer_DESTROY);
destruct(op);
}
}
#define Py_DECREF_MORTAL_SPECIALIZED(op, destruct) Py_DECREF_MORTAL_SPECIALIZED(_PyObject_CAST(op), destruct)
#endif
#else // Py_GIL_DISABLED
# define Py_DECREF_MORTAL(op) Py_DECREF(op)
# define Py_DECREF_MORTAL_SPECIALIZED(op, destruct) Py_DECREF(op)
#endif
/* Inline functions trading binary compatibility for speed:
_PyObject_Init() is the fast version of PyObject_Init(), and
_PyObject_InitVar() is the fast version of PyObject_InitVar().
These inline functions must not be called with op=NULL. */
static inline void
_PyObject_Init(PyObject *op, PyTypeObject *typeobj)
{
assert(op != NULL);
Py_SET_TYPE(op, typeobj);
assert(_PyType_HasFeature(typeobj, Py_TPFLAGS_HEAPTYPE) || _Py_IsImmortal(typeobj));
_Py_INCREF_TYPE(typeobj);
_Py_NewReference(op);
}
static inline void
_PyObject_InitVar(PyVarObject *op, PyTypeObject *typeobj, Py_ssize_t size)
{
assert(op != NULL);
assert(typeobj != &PyLong_Type);
_PyObject_Init((PyObject *)op, typeobj);
Py_SET_SIZE(op, size);
}
// Macros to accept any type for the parameter, and to automatically pass
// the filename and the filename (if NDEBUG is not defined) where the macro
// is called.
#ifdef NDEBUG
# define _PyObject_GC_TRACK(op) \
_PyObject_GC_TRACK(_PyObject_CAST(op))
# define _PyObject_GC_UNTRACK(op) \
_PyObject_GC_UNTRACK(_PyObject_CAST(op))
#else
# define _PyObject_GC_TRACK(op) \
_PyObject_GC_TRACK(__FILE__, __LINE__, _PyObject_CAST(op))
# define _PyObject_GC_UNTRACK(op) \
_PyObject_GC_UNTRACK(__FILE__, __LINE__, _PyObject_CAST(op))
#endif
#ifdef Py_GIL_DISABLED
/* Tries to increment an object's reference count
*
* This is a specialized version of _Py_TryIncref that only succeeds if the
* object is immortal or local to this thread. It does not handle the case
* where the reference count modification requires an atomic operation. This
* allows call sites to specialize for the immortal/local case.
*/
static inline int
_Py_TryIncrefFast(PyObject *op) {
uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local);
local += 1;
if (local == 0) {
// immortal
_Py_INCREF_IMMORTAL_STAT_INC();
return 1;
}
if (_Py_IsOwnedByCurrentThread(op)) {
_Py_INCREF_STAT_INC();
_Py_atomic_store_uint32_relaxed(&op->ob_ref_local, local);
#ifdef Py_REF_DEBUG
_Py_IncRefTotal(_PyThreadState_GET());
#endif
return 1;
}
return 0;
}
static inline int
_Py_TryIncRefShared(PyObject *op)
{
Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&op->ob_ref_shared);
for (;;) {
// If the shared refcount is zero and the object is either merged
// or may not have weak references, then we cannot incref it.
if (shared == 0 || shared == _Py_REF_MERGED) {
return 0;
}
if (_Py_atomic_compare_exchange_ssize(
&op->ob_ref_shared,
&shared,
shared + (1 << _Py_REF_SHARED_SHIFT))) {
#ifdef Py_REF_DEBUG
_Py_IncRefTotal(_PyThreadState_GET());
#endif
_Py_INCREF_STAT_INC();
return 1;
}
}
}
/* Tries to incref the object op and ensures that *src still points to it. */
static inline int
_Py_TryIncrefCompare(PyObject **src, PyObject *op)
{
if (_Py_TryIncrefFast(op)) {
return 1;
}
if (!_Py_TryIncRefShared(op)) {
return 0;
}
if (op != _Py_atomic_load_ptr(src)) {
Py_DECREF(op);
return 0;
}
return 1;
}
/* Loads and increfs an object from ptr, which may contain a NULL value.
Safe with concurrent (atomic) updates to ptr.
NOTE: The writer must set maybe-weakref on the stored object! */
static inline PyObject *
_Py_XGetRef(PyObject **ptr)
{
for (;;) {
PyObject *value = _PyObject_CAST(_Py_atomic_load_ptr(ptr));
if (value == NULL) {
return value;
}
if (_Py_TryIncrefCompare(ptr, value)) {
return value;
}
}
}
/* Attempts to loads and increfs an object from ptr. Returns NULL
on failure, which may be due to a NULL value or a concurrent update. */
static inline PyObject *
_Py_TryXGetRef(PyObject **ptr)
{
PyObject *value = _PyObject_CAST(_Py_atomic_load_ptr(ptr));
if (value == NULL) {
return value;
}
if (_Py_TryIncrefCompare(ptr, value)) {
return value;
}
return NULL;
}
/* Like Py_NewRef but also optimistically sets _Py_REF_MAYBE_WEAKREF
on objects owned by a different thread. */
static inline PyObject *
_Py_NewRefWithLock(PyObject *op)
{
if (_Py_TryIncrefFast(op)) {
return op;
}
#ifdef Py_REF_DEBUG
_Py_IncRefTotal(_PyThreadState_GET());
#endif
_Py_INCREF_STAT_INC();
for (;;) {
Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&op->ob_ref_shared);
Py_ssize_t new_shared = shared + (1 << _Py_REF_SHARED_SHIFT);
if ((shared & _Py_REF_SHARED_FLAG_MASK) == 0) {
new_shared |= _Py_REF_MAYBE_WEAKREF;
}
if (_Py_atomic_compare_exchange_ssize(
&op->ob_ref_shared,
&shared,
new_shared)) {
return op;
}
}
}
static inline PyObject *
_Py_XNewRefWithLock(PyObject *obj)
{
if (obj == NULL) {
return NULL;
}
return _Py_NewRefWithLock(obj);
}
static inline void
_PyObject_SetMaybeWeakref(PyObject *op)
{
if (_Py_IsImmortal(op)) {
return;
}
for (;;) {
Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&op->ob_ref_shared);
if ((shared & _Py_REF_SHARED_FLAG_MASK) != 0) {
// Nothing to do if it's in WEAKREFS, QUEUED, or MERGED states.
return;
}
if (_Py_atomic_compare_exchange_ssize(
&op->ob_ref_shared, &shared, shared | _Py_REF_MAYBE_WEAKREF)) {
return;
}
}
}
extern PyAPI_FUNC(int) _PyObject_ResurrectEndSlow(PyObject *op);
#endif
// Temporarily resurrects an object during deallocation. The refcount is set
// to one.
static inline void
_PyObject_ResurrectStart(PyObject *op)
{
assert(Py_REFCNT(op) == 0);
#ifdef Py_REF_DEBUG
_Py_IncRefTotal(_PyThreadState_GET());
#endif
#ifdef Py_GIL_DISABLED
_Py_atomic_store_uintptr_relaxed(&op->ob_tid, _Py_ThreadId());
_Py_atomic_store_uint32_relaxed(&op->ob_ref_local, 1);
_Py_atomic_store_ssize_relaxed(&op->ob_ref_shared, 0);
#else
Py_SET_REFCNT(op, 1);
#endif
#ifdef Py_TRACE_REFS
_Py_ResurrectReference(op);
#endif
}
// Undoes an object resurrection by decrementing the refcount without calling
// _Py_Dealloc(). Returns 0 if the object is dead (the normal case), and
// deallocation should continue. Returns 1 if the object is still alive.
static inline int
_PyObject_ResurrectEnd(PyObject *op)
{
#ifdef Py_REF_DEBUG
_Py_DecRefTotal(_PyThreadState_GET());
#endif
#ifndef Py_GIL_DISABLED
Py_SET_REFCNT(op, Py_REFCNT(op) - 1);
if (Py_REFCNT(op) == 0) {
# ifdef Py_TRACE_REFS
_Py_ForgetReference(op);
# endif
return 0;
}
return 1;
#else
uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local);
Py_ssize_t shared = _Py_atomic_load_ssize_acquire(&op->ob_ref_shared);
if (_Py_IsOwnedByCurrentThread(op) && local == 1 && shared == 0) {
// Fast-path: object has a single refcount and is owned by this thread
_Py_atomic_store_uint32_relaxed(&op->ob_ref_local, 0);
# ifdef Py_TRACE_REFS
_Py_ForgetReference(op);
# endif
return 0;
}
// Slow-path: object has a shared refcount or is not owned by this thread
return _PyObject_ResurrectEndSlow(op);
#endif
}
/* Tries to incref op and returns 1 if successful or 0 otherwise. */
static inline int
_Py_TryIncref(PyObject *op)
{
#ifdef Py_GIL_DISABLED
return _Py_TryIncrefFast(op) || _Py_TryIncRefShared(op);
#else
if (Py_REFCNT(op) > 0) {
Py_INCREF(op);
return 1;
}
return 0;
#endif
}
// Enqueue an object to be freed possibly after some delay
#ifdef Py_GIL_DISABLED
PyAPI_FUNC(void) _PyObject_XDecRefDelayed(PyObject *obj);
#else
static inline void _PyObject_XDecRefDelayed(PyObject *obj)
{
Py_XDECREF(obj);
}
#endif
#ifdef Py_GIL_DISABLED
// Same as `Py_XSETREF` but in free-threading, it stores the object atomically
// and queues the old object to be decrefed at a safe point using QSBR.
PyAPI_FUNC(void) _PyObject_XSetRefDelayed(PyObject **p_obj, PyObject *obj);
#else
static inline void _PyObject_XSetRefDelayed(PyObject **p_obj, PyObject *obj)
{
Py_XSETREF(*p_obj, obj);
}
#endif
#ifdef Py_REF_DEBUG
extern void _PyInterpreterState_FinalizeRefTotal(PyInterpreterState *);
extern void _Py_FinalizeRefTotal(_PyRuntimeState *);
extern void _PyDebug_PrintTotalRefs(void);
#endif
#ifdef Py_TRACE_REFS
extern void _Py_AddToAllObjects(PyObject *op);
extern void _Py_PrintReferences(PyInterpreterState *, FILE *);
extern void _Py_PrintReferenceAddresses(PyInterpreterState *, FILE *);
#endif
/* Return the *address* of the object's weaklist. The address may be
* dereferenced to get the current head of the weaklist. This is useful
* for iterating over the linked list of weakrefs, especially when the
* list is being modified externally (e.g. refs getting removed).
*
* The returned pointer should not be used to change the head of the list
* nor should it be used to add, remove, or swap any refs in the list.
* That is the sole responsibility of the code in weakrefobject.c.
*/
static inline PyObject **
_PyObject_GET_WEAKREFS_LISTPTR(PyObject *op)
{
if (PyType_Check(op) &&
((PyTypeObject *)op)->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(
interp, (PyTypeObject *)op);
return _PyStaticType_GET_WEAKREFS_LISTPTR(state);
}
// Essentially _PyObject_GET_WEAKREFS_LISTPTR_FROM_OFFSET():
Py_ssize_t offset = Py_TYPE(op)->tp_weaklistoffset;
return (PyObject **)((char *)op + offset);
}
/* This is a special case of _PyObject_GET_WEAKREFS_LISTPTR().
* Only the most fundamental lookup path is used.
* Consequently, static types should not be used.
*
* For static builtin types the returned pointer will always point
* to a NULL tp_weaklist. This is fine for any deallocation cases,
* since static types are never deallocated and static builtin types
* are only finalized at the end of runtime finalization.
*
* If the weaklist for static types is actually needed then use
* _PyObject_GET_WEAKREFS_LISTPTR().
*/
static inline PyWeakReference **
_PyObject_GET_WEAKREFS_LISTPTR_FROM_OFFSET(PyObject *op)
{
assert(!PyType_Check(op) ||
((PyTypeObject *)op)->tp_flags & Py_TPFLAGS_HEAPTYPE);
Py_ssize_t offset = Py_TYPE(op)->tp_weaklistoffset;
return (PyWeakReference **)((char *)op + offset);
}
// Fast inlined version of PyType_IS_GC()
#define _PyType_IS_GC(t) _PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
// Fast inlined version of PyObject_IS_GC()
static inline int
_PyObject_IS_GC(PyObject *obj)
{
PyTypeObject *type = Py_TYPE(obj);
return (_PyType_IS_GC(type)
&& (type->tp_is_gc == NULL || type->tp_is_gc(obj)));
}
// Fast inlined version of PyObject_Hash()
static inline Py_hash_t
_PyObject_HashFast(PyObject *op)
{
if (PyUnicode_CheckExact(op)) {
Py_hash_t hash = PyUnstable_Unicode_GET_CACHED_HASH(op);
if (hash != -1) {
return hash;
}
}
return PyObject_Hash(op);
}
static inline size_t
_PyType_PreHeaderSize(PyTypeObject *tp)
{
return (
#ifndef Py_GIL_DISABLED
(size_t)_PyType_IS_GC(tp) * sizeof(PyGC_Head) +
#endif
(size_t)_PyType_HasFeature(tp, Py_TPFLAGS_PREHEADER) * 2 * sizeof(PyObject *)
);
}
void _PyObject_GC_Link(PyObject *op);
// Usage: assert(_Py_CheckSlotResult(obj, "__getitem__", result != NULL));
extern int _Py_CheckSlotResult(
PyObject *obj,
const char *slot_name,
int success);
// Test if a type supports weak references
static inline int _PyType_SUPPORTS_WEAKREFS(PyTypeObject *type) {
return (type->tp_weaklistoffset != 0);
}
extern PyObject* _PyType_AllocNoTrack(PyTypeObject *type, Py_ssize_t nitems);
PyAPI_FUNC(PyObject *) _PyType_NewManagedObject(PyTypeObject *type);
extern PyTypeObject* _PyType_CalculateMetaclass(PyTypeObject *, PyObject *);
extern PyObject* _PyType_GetDocFromInternalDoc(const char *, const char *);
extern PyObject* _PyType_GetTextSignatureFromInternalDoc(const char *, const char *, int);
extern int _PyObject_SetAttributeErrorContext(PyObject *v, PyObject* name);
void _PyObject_InitInlineValues(PyObject *obj, PyTypeObject *tp);
extern int _PyObject_StoreInstanceAttribute(PyObject *obj,
PyObject *name, PyObject *value);
extern bool _PyObject_TryGetInstanceAttribute(PyObject *obj, PyObject *name,
PyObject **attr);
extern PyObject *_PyType_LookupRefAndVersion(PyTypeObject *, PyObject *,
unsigned int *);
// Internal API to look for a name through the MRO.
// This stores a stack reference in out and returns the value of
// type->tp_version or zero if name is missing. It doesn't set an exception!
extern unsigned int
_PyType_LookupStackRefAndVersion(PyTypeObject *type, PyObject *name, _PyStackRef *out);
PyAPI_FUNC(int) _PyObject_GetMethodStackRef(PyThreadState *ts, PyObject *obj,
PyObject *name, _PyStackRef *method);
// Like PyObject_GetAttr but returns a _PyStackRef. For types, this can
// return a deferred reference to reduce reference count contention.
PyAPI_FUNC(_PyStackRef) _PyObject_GetAttrStackRef(PyObject *obj, PyObject *name);
// Cache the provided init method in the specialization cache of type if the
// provided type version matches the current version of the type.
//
// The cached value is borrowed and is only valid if guarded by a type
// version check. In free-threaded builds the init method must also use
// deferred reference counting.
//
// Returns 1 if the value was cached or 0 otherwise.
extern int _PyType_CacheInitForSpecialization(PyHeapTypeObject *type,
PyObject *init,
unsigned int tp_version);
#ifdef Py_GIL_DISABLED
# define MANAGED_DICT_OFFSET (((Py_ssize_t)sizeof(PyObject *))*-1)
# define MANAGED_WEAKREF_OFFSET (((Py_ssize_t)sizeof(PyObject *))*-2)
#else
# define MANAGED_DICT_OFFSET (((Py_ssize_t)sizeof(PyObject *))*-3)
# define MANAGED_WEAKREF_OFFSET (((Py_ssize_t)sizeof(PyObject *))*-4)
#endif
typedef union {
PyDictObject *dict;
} PyManagedDictPointer;
static inline PyManagedDictPointer *
_PyObject_ManagedDictPointer(PyObject *obj)
{
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
return (PyManagedDictPointer *)((char *)obj + MANAGED_DICT_OFFSET);
}
static inline PyDictObject *
_PyObject_GetManagedDict(PyObject *obj)
{
PyManagedDictPointer *dorv = _PyObject_ManagedDictPointer(obj);
return (PyDictObject *)FT_ATOMIC_LOAD_PTR_ACQUIRE(dorv->dict);
}
static inline PyDictValues *
_PyObject_InlineValues(PyObject *obj)
{
PyTypeObject *tp = Py_TYPE(obj);
assert(tp->tp_basicsize > 0 && (size_t)tp->tp_basicsize % sizeof(PyObject *) == 0);
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_INLINE_VALUES);
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
return (PyDictValues *)((char *)obj + tp->tp_basicsize);
}
extern PyObject ** _PyObject_ComputedDictPointer(PyObject *);
extern int _PyObject_IsInstanceDictEmpty(PyObject *);
// Export for 'math' shared extension
PyAPI_FUNC(PyObject*) _PyObject_LookupSpecial(PyObject *, PyObject *);
PyAPI_FUNC(int) _PyObject_LookupSpecialMethod(PyObject *attr, _PyStackRef *method_and_self);
// Calls the method named `attr` on `self`, but does not set an exception if
// the attribute does not exist.
PyAPI_FUNC(PyObject *)
_PyObject_MaybeCallSpecialNoArgs(PyObject *self, PyObject *attr);
PyAPI_FUNC(PyObject *)
_PyObject_MaybeCallSpecialOneArg(PyObject *self, PyObject *attr, PyObject *arg);
extern int _PyObject_IsAbstract(PyObject *);
PyAPI_FUNC(int) _PyObject_GetMethod(PyObject *obj, PyObject *name, PyObject **method);
extern PyObject* _PyObject_NextNotImplemented(PyObject *);
// Pickle support.
// Export for '_datetime' shared extension
PyAPI_FUNC(PyObject*) _PyObject_GetState(PyObject *);
/* C function call trampolines to mitigate bad function pointer casts.
*
* Typical native ABIs ignore additional arguments or fill in missing
* values with 0/NULL in function pointer cast. Compilers do not show
* warnings when a function pointer is explicitly casted to an
* incompatible type.
*
* Bad fpcasts are an issue in WebAssembly. WASM's indirect_call has strict
* function signature checks. Argument count, types, and return type must
* match.
*
* Third party code unintentionally rely on problematic fpcasts. The call
* trampoline mitigates common occurrences of bad fpcasts on Emscripten.
*/
#if !(defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE))
#define _PyCFunction_TrampolineCall(meth, self, args) \
(meth)((self), (args))
#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
(meth)((self), (args), (kw))
#endif // __EMSCRIPTEN__ && PY_CALL_TRAMPOLINE
// Export these 2 symbols for '_pickle' shared extension
PyAPI_DATA(PyTypeObject) _PyNone_Type;
PyAPI_DATA(PyTypeObject) _PyNotImplemented_Type;