-
-
Notifications
You must be signed in to change notification settings - Fork 34.2k
Expand file tree
/
Copy pathpyatomic.h
More file actions
625 lines (456 loc) · 17.8 KB
/
pyatomic.h
File metadata and controls
625 lines (456 loc) · 17.8 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
// This header provides cross-platform low-level atomic operations
// similar to C11 atomics.
//
// Operations are sequentially consistent unless they have a suffix indicating
// otherwise. If in doubt, prefer the sequentially consistent operations.
//
// The "_relaxed" suffix for load and store operations indicates the "relaxed"
// memory order. They don't provide synchronization, but (roughly speaking)
// guarantee somewhat sane behavior for races instead of undefined behavior.
// In practice, they correspond to "normal" hardware load and store
// instructions, so they are almost as inexpensive as plain loads and stores
// in C.
//
// Note that atomic read-modify-write operations like _Py_atomic_add_* return
// the previous value of the atomic variable, not the new value.
//
// See https://en.cppreference.com/w/c/atomic for more information on C11
// atomics.
// See https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2055r0.pdf
// "A Relaxed Guide to memory_order_relaxed" for discussion of and common usage
// or relaxed atomics.
//
// Functions with pseudo Python code:
//
// def _Py_atomic_load(obj):
// return obj # sequential consistency
//
// def _Py_atomic_load_relaxed(obj):
// return obj # relaxed consistency
//
// def _Py_atomic_store(obj, value):
// obj = value # sequential consistency
//
// def _Py_atomic_store_relaxed(obj, value):
// obj = value # relaxed consistency
//
// def _Py_atomic_exchange(obj, value):
// # sequential consistency
// old_obj = obj
// obj = value
// return old_obj
//
// def _Py_atomic_compare_exchange(obj, expected, desired):
// # sequential consistency
// if obj == expected:
// obj = desired
// return True
// else:
// expected = obj
// return False
//
// def _Py_atomic_add(obj, value):
// # sequential consistency
// old_obj = obj
// obj += value
// return old_obj
//
// def _Py_atomic_and(obj, value):
// # sequential consistency
// old_obj = obj
// obj &= value
// return old_obj
//
// def _Py_atomic_or(obj, value):
// # sequential consistency
// old_obj = obj
// obj |= value
// return old_obj
//
// Other functions:
//
// def _Py_atomic_load_ptr_acquire(obj):
// return obj # acquire
//
// def _Py_atomic_store_ptr_release(obj):
// return obj # release
//
// def _Py_atomic_fence_seq_cst():
// # sequential consistency
// ...
//
// def _Py_atomic_fence_release():
// # release
// ...
#ifndef Py_CPYTHON_ATOMIC_H
# error "this header file must not be included directly"
#endif
// --- _Py_atomic_add --------------------------------------------------------
// Atomically adds `value` to `obj` and returns the previous value
static inline int
_Py_atomic_add_int(int *obj, int value);
static inline int8_t
_Py_atomic_add_int8(int8_t *obj, int8_t value);
static inline int16_t
_Py_atomic_add_int16(int16_t *obj, int16_t value);
static inline int32_t
_Py_atomic_add_int32(int32_t *obj, int32_t value);
static inline int64_t
_Py_atomic_add_int64(int64_t *obj, int64_t value);
static inline intptr_t
_Py_atomic_add_intptr(intptr_t *obj, intptr_t value);
static inline unsigned int
_Py_atomic_add_uint(unsigned int *obj, unsigned int value);
static inline uint8_t
_Py_atomic_add_uint8(uint8_t *obj, uint8_t value);
static inline uint16_t
_Py_atomic_add_uint16(uint16_t *obj, uint16_t value);
static inline uint32_t
_Py_atomic_add_uint32(uint32_t *obj, uint32_t value);
static inline uint64_t
_Py_atomic_add_uint64(uint64_t *obj, uint64_t value);
static inline uintptr_t
_Py_atomic_add_uintptr(uintptr_t *obj, uintptr_t value);
static inline Py_ssize_t
_Py_atomic_add_ssize(Py_ssize_t *obj, Py_ssize_t value);
// --- _Py_atomic_compare_exchange -------------------------------------------
// Performs an atomic compare-and-exchange.
//
// - If `*obj` and `*expected` are equal, store `desired` into `*obj`
// and return 1 (success).
// - Otherwise, store the `*obj` current value into `*expected`
// and return 0 (failure).
//
// These correspond to the C11 atomic_compare_exchange_strong() function.
static inline int
_Py_atomic_compare_exchange_int(int *obj, int *expected, int desired);
static inline int
_Py_atomic_compare_exchange_int8(int8_t *obj, int8_t *expected, int8_t desired);
static inline int
_Py_atomic_compare_exchange_int16(int16_t *obj, int16_t *expected, int16_t desired);
static inline int
_Py_atomic_compare_exchange_int32(int32_t *obj, int32_t *expected, int32_t desired);
static inline int
_Py_atomic_compare_exchange_int64(int64_t *obj, int64_t *expected, int64_t desired);
static inline int
_Py_atomic_compare_exchange_intptr(intptr_t *obj, intptr_t *expected, intptr_t desired);
static inline int
_Py_atomic_compare_exchange_uint(unsigned int *obj, unsigned int *expected, unsigned int desired);
static inline int
_Py_atomic_compare_exchange_uint8(uint8_t *obj, uint8_t *expected, uint8_t desired);
static inline int
_Py_atomic_compare_exchange_uint16(uint16_t *obj, uint16_t *expected, uint16_t desired);
static inline int
_Py_atomic_compare_exchange_uint32(uint32_t *obj, uint32_t *expected, uint32_t desired);
static inline int
_Py_atomic_compare_exchange_uint64(uint64_t *obj, uint64_t *expected, uint64_t desired);
static inline int
_Py_atomic_compare_exchange_uintptr(uintptr_t *obj, uintptr_t *expected, uintptr_t desired);
static inline int
_Py_atomic_compare_exchange_ssize(Py_ssize_t *obj, Py_ssize_t *expected, Py_ssize_t desired);
// NOTE: `obj` and `expected` are logically `void**` types, but we use `void*`
// so that we can pass types like `PyObject**` without a cast.
static inline int
_Py_atomic_compare_exchange_ptr(void *obj, void *expected, void *value);
// --- _Py_atomic_exchange ---------------------------------------------------
// Atomically replaces `*obj` with `value` and returns the previous value of `*obj`.
static inline int
_Py_atomic_exchange_int(int *obj, int value);
static inline int8_t
_Py_atomic_exchange_int8(int8_t *obj, int8_t value);
static inline int16_t
_Py_atomic_exchange_int16(int16_t *obj, int16_t value);
static inline int32_t
_Py_atomic_exchange_int32(int32_t *obj, int32_t value);
static inline int64_t
_Py_atomic_exchange_int64(int64_t *obj, int64_t value);
static inline intptr_t
_Py_atomic_exchange_intptr(intptr_t *obj, intptr_t value);
static inline unsigned int
_Py_atomic_exchange_uint(unsigned int *obj, unsigned int value);
static inline uint8_t
_Py_atomic_exchange_uint8(uint8_t *obj, uint8_t value);
static inline uint16_t
_Py_atomic_exchange_uint16(uint16_t *obj, uint16_t value);
static inline uint32_t
_Py_atomic_exchange_uint32(uint32_t *obj, uint32_t value);
static inline uint64_t
_Py_atomic_exchange_uint64(uint64_t *obj, uint64_t value);
static inline uintptr_t
_Py_atomic_exchange_uintptr(uintptr_t *obj, uintptr_t value);
static inline Py_ssize_t
_Py_atomic_exchange_ssize(Py_ssize_t *obj, Py_ssize_t value);
static inline void *
_Py_atomic_exchange_ptr(void *obj, void *value);
// --- _Py_atomic_and --------------------------------------------------------
// Performs `*obj &= value` atomically and returns the previous value of `*obj`.
static inline uint8_t
_Py_atomic_and_uint8(uint8_t *obj, uint8_t value);
static inline uint16_t
_Py_atomic_and_uint16(uint16_t *obj, uint16_t value);
static inline uint32_t
_Py_atomic_and_uint32(uint32_t *obj, uint32_t value);
static inline uint64_t
_Py_atomic_and_uint64(uint64_t *obj, uint64_t value);
static inline uintptr_t
_Py_atomic_and_uintptr(uintptr_t *obj, uintptr_t value);
// --- _Py_atomic_or ---------------------------------------------------------
// Performs `*obj |= value` atomically and returns the previous value of `*obj`.
static inline uint8_t
_Py_atomic_or_uint8(uint8_t *obj, uint8_t value);
static inline uint16_t
_Py_atomic_or_uint16(uint16_t *obj, uint16_t value);
static inline uint32_t
_Py_atomic_or_uint32(uint32_t *obj, uint32_t value);
static inline uint64_t
_Py_atomic_or_uint64(uint64_t *obj, uint64_t value);
static inline uintptr_t
_Py_atomic_or_uintptr(uintptr_t *obj, uintptr_t value);
// --- _Py_atomic_load -------------------------------------------------------
// Atomically loads `*obj` (sequential consistency)
static inline int
_Py_atomic_load_int(const int *obj);
static inline int8_t
_Py_atomic_load_int8(const int8_t *obj);
static inline int16_t
_Py_atomic_load_int16(const int16_t *obj);
static inline int32_t
_Py_atomic_load_int32(const int32_t *obj);
static inline int64_t
_Py_atomic_load_int64(const int64_t *obj);
static inline intptr_t
_Py_atomic_load_intptr(const intptr_t *obj);
static inline uint8_t
_Py_atomic_load_uint8(const uint8_t *obj);
static inline uint16_t
_Py_atomic_load_uint16(const uint16_t *obj);
static inline uint32_t
_Py_atomic_load_uint32(const uint32_t *obj);
static inline uint64_t
_Py_atomic_load_uint64(const uint64_t *obj);
static inline uintptr_t
_Py_atomic_load_uintptr(const uintptr_t *obj);
static inline unsigned int
_Py_atomic_load_uint(const unsigned int *obj);
static inline Py_ssize_t
_Py_atomic_load_ssize(const Py_ssize_t *obj);
static inline void *
_Py_atomic_load_ptr(const void *obj);
// --- _Py_atomic_load_relaxed -----------------------------------------------
// Loads `*obj` (relaxed consistency, i.e., no ordering)
static inline int
_Py_atomic_load_int_relaxed(const int *obj);
static inline char
_Py_atomic_load_char_relaxed(const char *obj);
static inline unsigned char
_Py_atomic_load_uchar_relaxed(const unsigned char *obj);
static inline short
_Py_atomic_load_short_relaxed(const short *obj);
static inline unsigned short
_Py_atomic_load_ushort_relaxed(const unsigned short *obj);
static inline long
_Py_atomic_load_long_relaxed(const long *obj);
static inline double
_Py_atomic_load_double_relaxed(const double *obj);
static inline long long
_Py_atomic_load_llong_relaxed(const long long *obj);
static inline int8_t
_Py_atomic_load_int8_relaxed(const int8_t *obj);
static inline int16_t
_Py_atomic_load_int16_relaxed(const int16_t *obj);
static inline int32_t
_Py_atomic_load_int32_relaxed(const int32_t *obj);
static inline int64_t
_Py_atomic_load_int64_relaxed(const int64_t *obj);
static inline intptr_t
_Py_atomic_load_intptr_relaxed(const intptr_t *obj);
static inline uint8_t
_Py_atomic_load_uint8_relaxed(const uint8_t *obj);
static inline uint16_t
_Py_atomic_load_uint16_relaxed(const uint16_t *obj);
static inline uint32_t
_Py_atomic_load_uint32_relaxed(const uint32_t *obj);
static inline uint64_t
_Py_atomic_load_uint64_relaxed(const uint64_t *obj);
static inline uintptr_t
_Py_atomic_load_uintptr_relaxed(const uintptr_t *obj);
static inline unsigned int
_Py_atomic_load_uint_relaxed(const unsigned int *obj);
static inline Py_ssize_t
_Py_atomic_load_ssize_relaxed(const Py_ssize_t *obj);
static inline void *
_Py_atomic_load_ptr_relaxed(const void *obj);
static inline unsigned long long
_Py_atomic_load_ullong_relaxed(const unsigned long long *obj);
// --- _Py_atomic_store ------------------------------------------------------
// Atomically performs `*obj = value` (sequential consistency)
static inline void
_Py_atomic_store_int(int *obj, int value);
static inline void
_Py_atomic_store_int8(int8_t *obj, int8_t value);
static inline void
_Py_atomic_store_int16(int16_t *obj, int16_t value);
static inline void
_Py_atomic_store_int32(int32_t *obj, int32_t value);
static inline void
_Py_atomic_store_int64(int64_t *obj, int64_t value);
static inline void
_Py_atomic_store_intptr(intptr_t *obj, intptr_t value);
static inline void
_Py_atomic_store_uint8(uint8_t *obj, uint8_t value);
static inline void
_Py_atomic_store_uint16(uint16_t *obj, uint16_t value);
static inline void
_Py_atomic_store_uint32(uint32_t *obj, uint32_t value);
static inline void
_Py_atomic_store_uint64(uint64_t *obj, uint64_t value);
static inline void
_Py_atomic_store_uintptr(uintptr_t *obj, uintptr_t value);
static inline void
_Py_atomic_store_uint(unsigned int *obj, unsigned int value);
static inline void
_Py_atomic_store_ptr(void *obj, void *value);
static inline void
_Py_atomic_store_ssize(Py_ssize_t* obj, Py_ssize_t value);
// --- _Py_atomic_store_relaxed ----------------------------------------------
// Stores `*obj = value` (relaxed consistency, i.e., no ordering)
static inline void
_Py_atomic_store_int_relaxed(int *obj, int value);
static inline void
_Py_atomic_store_int8_relaxed(int8_t *obj, int8_t value);
static inline void
_Py_atomic_store_int16_relaxed(int16_t *obj, int16_t value);
static inline void
_Py_atomic_store_int32_relaxed(int32_t *obj, int32_t value);
static inline void
_Py_atomic_store_int64_relaxed(int64_t *obj, int64_t value);
static inline void
_Py_atomic_store_intptr_relaxed(intptr_t *obj, intptr_t value);
static inline void
_Py_atomic_store_uint8_relaxed(uint8_t* obj, uint8_t value);
static inline void
_Py_atomic_store_uint16_relaxed(uint16_t *obj, uint16_t value);
static inline void
_Py_atomic_store_uint32_relaxed(uint32_t *obj, uint32_t value);
static inline void
_Py_atomic_store_uint64_relaxed(uint64_t *obj, uint64_t value);
static inline void
_Py_atomic_store_uintptr_relaxed(uintptr_t *obj, uintptr_t value);
static inline void
_Py_atomic_store_uint_relaxed(unsigned int *obj, unsigned int value);
static inline void
_Py_atomic_store_ptr_relaxed(void *obj, void *value);
static inline void
_Py_atomic_store_ssize_relaxed(Py_ssize_t *obj, Py_ssize_t value);
static inline void
_Py_atomic_store_ullong_relaxed(unsigned long long *obj,
unsigned long long value);
static inline void
_Py_atomic_store_char_relaxed(char *obj, char value);
static inline void
_Py_atomic_store_uchar_relaxed(unsigned char *obj, unsigned char value);
static inline void
_Py_atomic_store_short_relaxed(short *obj, short value);
static inline void
_Py_atomic_store_ushort_relaxed(unsigned short *obj, unsigned short value);
static inline void
_Py_atomic_store_long_relaxed(long *obj, long value);
static inline void
_Py_atomic_store_float_relaxed(float *obj, float value);
static inline void
_Py_atomic_store_double_relaxed(double *obj, double value);
static inline void
_Py_atomic_store_llong_relaxed(long long *obj, long long value);
// --- _Py_atomic_load_ptr_acquire / _Py_atomic_store_ptr_release ------------
// Loads `*obj` (acquire operation)
static inline void *
_Py_atomic_load_ptr_acquire(const void *obj);
static inline uintptr_t
_Py_atomic_load_uintptr_acquire(const uintptr_t *obj);
// Stores `*obj = value` (release operation)
static inline void
_Py_atomic_store_ptr_release(void *obj, void *value);
static inline void
_Py_atomic_store_uintptr_release(uintptr_t *obj, uintptr_t value);
static inline void
_Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value);
static inline void
_Py_atomic_store_int_release(int *obj, int value);
static inline int
_Py_atomic_load_int_acquire(const int *obj);
static inline void
_Py_atomic_store_uint32_release(uint32_t *obj, uint32_t value);
static inline void
_Py_atomic_store_uint64_release(uint64_t *obj, uint64_t value);
static inline uint64_t
_Py_atomic_load_uint64_acquire(const uint64_t *obj);
static inline uint32_t
_Py_atomic_load_uint32_acquire(const uint32_t *obj);
static inline Py_ssize_t
_Py_atomic_load_ssize_acquire(const Py_ssize_t *obj);
// --- _Py_atomic_fence ------------------------------------------------------
// Sequential consistency fence. C11 fences have complex semantics. When
// possible, use the atomic operations on variables defined above, which
// generally do not require explicit use of a fence.
// See https://en.cppreference.com/w/cpp/atomic/atomic_thread_fence
static inline void _Py_atomic_fence_seq_cst(void);
// Acquire fence
static inline void _Py_atomic_fence_acquire(void);
// Release fence
static inline void _Py_atomic_fence_release(void);
#ifndef _Py_USE_GCC_BUILTIN_ATOMICS
# if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))
# define _Py_USE_GCC_BUILTIN_ATOMICS 1
# elif defined(__clang__)
# if __has_builtin(__atomic_load)
# define _Py_USE_GCC_BUILTIN_ATOMICS 1
# endif
# endif
#endif
#if _Py_USE_GCC_BUILTIN_ATOMICS
# define Py_ATOMIC_GCC_H
# include "pyatomic_gcc.h"
# undef Py_ATOMIC_GCC_H
#elif __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__)
# define Py_ATOMIC_STD_H
# include "pyatomic_std.h"
# undef Py_ATOMIC_STD_H
#elif defined(_MSC_VER)
# define Py_ATOMIC_MSC_H
# include "pyatomic_msc.h"
# undef Py_ATOMIC_MSC_H
#else
# error "no available pyatomic implementation for this platform/compiler"
#endif
// --- aliases ---------------------------------------------------------------
// Compilers don't really support "consume" semantics, so we fake it. Use
// "acquire" with TSan to support false positives. Use "relaxed" otherwise,
// because CPUs on all platforms we support respect address dependencies without
// extra barriers.
// See 2.6.7 in https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2055r0.pdf
#if defined(_Py_THREAD_SANITIZER)
# define _Py_atomic_load_ptr_consume _Py_atomic_load_ptr_acquire
#else
# define _Py_atomic_load_ptr_consume _Py_atomic_load_ptr_relaxed
#endif
#if SIZEOF_LONG == 8
# define _Py_atomic_load_ulong(p) \
_Py_atomic_load_uint64((uint64_t *)p)
# define _Py_atomic_load_ulong_relaxed(p) \
_Py_atomic_load_uint64_relaxed((uint64_t *)p)
# define _Py_atomic_store_ulong(p, v) \
_Py_atomic_store_uint64((uint64_t *)p, v)
# define _Py_atomic_store_ulong_relaxed(p, v) \
_Py_atomic_store_uint64_relaxed((uint64_t *)p, v)
#elif SIZEOF_LONG == 4
# define _Py_atomic_load_ulong(p) \
_Py_atomic_load_uint32((uint32_t *)p)
# define _Py_atomic_load_ulong_relaxed(p) \
_Py_atomic_load_uint32_relaxed((uint32_t *)p)
# define _Py_atomic_store_ulong(p, v) \
_Py_atomic_store_uint32((uint32_t *)p, v)
# define _Py_atomic_store_ulong_relaxed(p, v) \
_Py_atomic_store_uint32_relaxed((uint32_t *)p, v)
#else
# error "long must be 4 or 8 bytes in size"
#endif // SIZEOF_LONG