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stdatomic.h
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1#pragma once
2/*
3 * An implementation of C11 stdatomic.h directly borrowed from FreeBSD
4 * (original copyright follows), with minor modifications for
5 * portability to other systems. Works for recent Clang (that
6 * implement the feature c_atomic) and GCC 4.7+; includes
7 * compatibility for GCC below 4.7 but I wouldn't recommend it.
8 *
9 * Caveats and limitations:
10 * - Only the ``_Atomic parentheses'' notation is implemented, while
11 * the ``_Atomic space'' one is not.
12 * - _Atomic types must be typedef'ed, or programs using them will
13 * not type check correctly (incompatible anonymous structure
14 * types).
15 * - Non-scalar _Atomic types would require runtime support for
16 * runtime locking, which, as far as I know, is not currently
17 * available on any system.
18 */
19
20/*-
21 * @copyright (c) 2011 Ed Schouten (ed@FreeBSD.org)
22 * David Chisnall <theraven@FreeBSD.org>
23 * All rights reserved.
24 *
25 * Redistribution and use in source and binary forms, with or without
26 * modification, are permitted provided that the following conditions
27 * are met:
28 * 1. Redistributions of source code must retain the above copyright
29 * notice, this list of conditions and the following disclaimer.
30 * 2. Redistributions in binary form must reproduce the above copyright
31 * notice, this list of conditions and the following disclaimer in the
32 * documentation and/or other materials provided with the distribution.
33 *
34 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 *
46 * $FreeBSD: src/include/stdatomic.h,v 1.10.2.2 2012/05/30 19:21:54 theraven Exp $
47 */
48#include <stddef.h>
49#include <stdint.h>
50
51#if !defined(__has_feature)
52#define __has_feature(x) 0
53#endif
54#if !defined(__has_builtin)
55#define __has_builtin(x) 0
56#endif
57#if !defined(__GNUC_PREREQ__)
58#if defined(__GNUC__) && defined(__GNUC_MINOR__)
59#define __GNUC_PREREQ__(maj, min) \
60 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
61#else
62#define __GNUC_PREREQ__(maj, min) 0
63#endif
64#endif
65
66#if !defined(__CLANG_ATOMICS) && !defined(__GNUC_ATOMICS)
67#if __has_feature(c_atomic)
68#define __CLANG_ATOMICS
69#elif __GNUC_PREREQ__(4, 7)
70#define __GNUC_ATOMICS
71#elif !defined(__GNUC__)
72#error "stdatomic.h does not support your compiler"
73#endif
74#endif
75
76#if !defined(__CLANG_ATOMICS)
77#define _Atomic(T) struct { volatile __typeof__(T) __val; }
78#endif
79
80/*
81 * 7.17.2 Initialization.
82 */
83
84#if defined(__CLANG_ATOMICS)
85#define ATOMIC_VAR_INIT(value) (value)
86#define atomic_init(obj, value) __c11_atomic_init(obj, value)
87#else
88#define ATOMIC_VAR_INIT(value) { .__val = (value) }
89#define atomic_init(obj, value) do { \
90 (obj)->__val = (value); \
91} while (0)
92#endif
93
94/*
95 * Clang and recent GCC both provide predefined macros for the memory
96 * orderings. If we are using a compiler that doesn't define them, use the
97 * clang values - these will be ignored in the fallback path.
98 */
99
100#ifndef __ATOMIC_RELAXED
101#define __ATOMIC_RELAXED 0
102#endif
103#ifndef __ATOMIC_CONSUME
104#define __ATOMIC_CONSUME 1
105#endif
106#ifndef __ATOMIC_ACQUIRE
107#define __ATOMIC_ACQUIRE 2
108#endif
109#ifndef __ATOMIC_RELEASE
110#define __ATOMIC_RELEASE 3
111#endif
112#ifndef __ATOMIC_ACQ_REL
113#define __ATOMIC_ACQ_REL 4
114#endif
115#ifndef __ATOMIC_SEQ_CST
116#define __ATOMIC_SEQ_CST 5
117#endif
118
119/*
120 * 7.17.3 Order and consistency.
121 *
122 * The memory_order_* constants that denote the barrier behaviour of the
123 * atomic operations.
124 */
125
134
135typedef enum memory_order memory_order;
136
137/*
138 * 7.17.4 Fences.
139 */
140
141#ifdef __CLANG_ATOMICS
142#define atomic_thread_fence(order) __c11_atomic_thread_fence(order)
143#define atomic_signal_fence(order) __c11_atomic_signal_fence(order)
144#elif defined(__GNUC_ATOMICS)
145#define atomic_thread_fence(order) __atomic_thread_fence(order)
146#define atomic_signal_fence(order) __atomic_signal_fence(order)
147#else
148#define atomic_thread_fence(order) __sync_synchronize()
149#define atomic_signal_fence(order) __asm volatile ("" : : : "memory")
150#endif
151
152/*
153 * 7.17.5 Lock-free property.
154 */
155
156#if defined(__CLANG_ATOMICS)
157#define atomic_is_lock_free(obj) \
158 __c11_atomic_is_lock_free(sizeof(obj))
159#elif defined(__GNUC_ATOMICS)
160#define atomic_is_lock_free(obj) \
161 __atomic_is_lock_free(sizeof((obj)->__val))
162#else
163#define atomic_is_lock_free(obj) \
164 (sizeof((obj)->__val) <= sizeof(void *))
165#endif
166
167/*
168 * 7.17.6 Atomic integer types.
169 */
170
171typedef _Atomic(_Bool) atomic_bool;
172typedef _Atomic(char) atomic_char;
173typedef _Atomic(signed char) atomic_schar;
174typedef _Atomic(unsigned char) atomic_uchar;
175typedef _Atomic(short) atomic_short;
176typedef _Atomic(unsigned short) atomic_ushort;
177typedef _Atomic(int) atomic_int;
178typedef _Atomic(unsigned int) atomic_uint;
179typedef _Atomic(long) atomic_long;
180typedef _Atomic(unsigned long) atomic_ulong;
181typedef _Atomic(long long) atomic_llong;
182typedef _Atomic(unsigned long long) atomic_ullong;
183#if 0
184typedef _Atomic(char16_t) atomic_char16_t;
185typedef _Atomic(char32_t) atomic_char32_t;
186#endif
187typedef _Atomic(wchar_t) atomic_wchar_t;
188typedef _Atomic(int_least8_t) atomic_int_least8_t;
189typedef _Atomic(uint_least8_t) atomic_uint_least8_t;
190typedef _Atomic(int_least16_t) atomic_int_least16_t;
191typedef _Atomic(uint_least16_t) atomic_uint_least16_t;
192typedef _Atomic(int_least32_t) atomic_int_least32_t;
193typedef _Atomic(uint_least32_t) atomic_uint_least32_t;
194typedef _Atomic(int_least64_t) atomic_int_least64_t;
195typedef _Atomic(uint_least64_t) atomic_uint_least64_t;
196typedef _Atomic(int_fast8_t) atomic_int_fast8_t;
197typedef _Atomic(uint_fast8_t) atomic_uint_fast8_t;
198typedef _Atomic(int_fast16_t) atomic_int_fast16_t;
199typedef _Atomic(uint_fast16_t) atomic_uint_fast16_t;
200typedef _Atomic(int_fast32_t) atomic_int_fast32_t;
201typedef _Atomic(uint_fast32_t) atomic_uint_fast32_t;
202typedef _Atomic(int_fast64_t) atomic_int_fast64_t;
203typedef _Atomic(uint_fast64_t) atomic_uint_fast64_t;
204typedef _Atomic(intptr_t) atomic_intptr_t;
205typedef _Atomic(uintptr_t) atomic_uintptr_t;
206typedef _Atomic(size_t) atomic_size_t;
207typedef _Atomic(ptrdiff_t) atomic_ptrdiff_t;
208typedef _Atomic(intmax_t) atomic_intmax_t;
209typedef _Atomic(uintmax_t) atomic_uintmax_t;
210
211/*
212 * 7.17.7 Operations on atomic types.
213 */
214
215/*
216 * Compiler-specific operations.
217 */
218
219#if defined(__CLANG_ATOMICS)
220#define atomic_compare_exchange_strong_explicit(object, expected, \
221 desired, success, failure) \
222 __c11_atomic_compare_exchange_strong(object, expected, desired, \
223 success, failure)
224#define atomic_compare_exchange_weak_explicit(object, expected, \
225 desired, success, failure) \
226 __c11_atomic_compare_exchange_weak(object, expected, desired, \
227 success, failure)
228#define atomic_exchange_explicit(object, desired, order) \
229 __c11_atomic_exchange(object, desired, order)
230#define atomic_fetch_add_explicit(object, operand, order) \
231 __c11_atomic_fetch_add(object, operand, order)
232#define atomic_fetch_and_explicit(object, operand, order) \
233 __c11_atomic_fetch_and(object, operand, order)
234#define atomic_fetch_or_explicit(object, operand, order) \
235 __c11_atomic_fetch_or(object, operand, order)
236#define atomic_fetch_sub_explicit(object, operand, order) \
237 __c11_atomic_fetch_sub(object, operand, order)
238#define atomic_fetch_xor_explicit(object, operand, order) \
239 __c11_atomic_fetch_xor(object, operand, order)
240#define atomic_load_explicit(object, order) \
241 __c11_atomic_load(object, order)
242#define atomic_store_explicit(object, desired, order) \
243 __c11_atomic_store(object, desired, order)
244#elif defined(__GNUC_ATOMICS)
245#define atomic_compare_exchange_strong_explicit(object, expected, \
246 desired, success, failure) \
247 __atomic_compare_exchange_n(&(object)->__val, expected, \
248 desired, 0, success, failure)
249#define atomic_compare_exchange_weak_explicit(object, expected, \
250 desired, success, failure) \
251 __atomic_compare_exchange_n(&(object)->__val, expected, \
252 desired, 1, success, failure)
253#define atomic_exchange_explicit(object, desired, order) \
254 __atomic_exchange_n(&(object)->__val, desired, order)
255#define atomic_fetch_add_explicit(object, operand, order) \
256 __atomic_fetch_add(&(object)->__val, operand, order)
257#define atomic_fetch_and_explicit(object, operand, order) \
258 __atomic_fetch_and(&(object)->__val, operand, order)
259#define atomic_fetch_or_explicit(object, operand, order) \
260 __atomic_fetch_or(&(object)->__val, operand, order)
261#define atomic_fetch_sub_explicit(object, operand, order) \
262 __atomic_fetch_sub(&(object)->__val, operand, order)
263#define atomic_fetch_xor_explicit(object, operand, order) \
264 __atomic_fetch_xor(&(object)->__val, operand, order)
265#define atomic_load_explicit(object, order) \
266 __atomic_load_n(&(object)->__val, order)
267#define atomic_store_explicit(object, desired, order) \
268 __atomic_store_n(&(object)->__val, desired, order)
269#else
270#define atomic_compare_exchange_strong_explicit(object, expected, \
271 desired, success, failure) ({ \
272 __typeof__((object)->__val) __v; \
273 _Bool __r; \
274 __v = __sync_val_compare_and_swap(&(object)->__val, \
275 *(expected), desired); \
276 __r = *(expected) == __v; \
277 *(expected) = __v; \
278 __r; \
279})
280
281#define atomic_compare_exchange_weak_explicit(object, expected, \
282 desired, success, failure) \
283 atomic_compare_exchange_strong_explicit(object, expected, \
284 desired, success, failure)
285#if __has_builtin(__sync_swap)
286/* Clang provides a full-barrier atomic exchange - use it if available. */
287#define atomic_exchange_explicit(object, desired, order) \
288 __sync_swap(&(object)->__val, desired)
289#else
290/*
291 * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
292 * practice it is usually a full barrier) so we need an explicit barrier after
293 * it.
294 */
295#define atomic_exchange_explicit(object, desired, order) ({ \
296 __typeof__((object)->__val) __v; \
297 __v = __sync_lock_test_and_set(&(object)->__val, desired); \
298 __sync_synchronize(); \
299 __v; \
300})
301#endif
302#define atomic_fetch_add_explicit(object, operand, order) \
303 __sync_fetch_and_add(&(object)->__val, operand)
304#define atomic_fetch_and_explicit(object, operand, order) \
305 __sync_fetch_and_and(&(object)->__val, operand)
306#define atomic_fetch_or_explicit(object, operand, order) \
307 __sync_fetch_and_or(&(object)->__val, operand)
308#define atomic_fetch_sub_explicit(object, operand, order) \
309 __sync_fetch_and_sub(&(object)->__val, operand)
310#define atomic_fetch_xor_explicit(object, operand, order) \
311 __sync_fetch_and_xor(&(object)->__val, operand)
312#define atomic_load_explicit(object, order) \
313 __sync_fetch_and_add(&(object)->__val, 0)
314#define atomic_store_explicit(object, desired, order) do { \
315 __sync_synchronize(); \
316 (object)->__val = (desired); \
317 __sync_synchronize(); \
318} while (0)
319#endif
320
321/*
322 * Convenience functions.
323 */
324
325#define atomic_compare_exchange_strong(object, expected, desired) \
326 atomic_compare_exchange_strong_explicit(object, expected, \
327 desired, memory_order_seq_cst, memory_order_seq_cst)
328#define atomic_compare_exchange_weak(object, expected, desired) \
329 atomic_compare_exchange_weak_explicit(object, expected, \
330 desired, memory_order_seq_cst, memory_order_seq_cst)
331#define atomic_exchange(object, desired) \
332 atomic_exchange_explicit(object, desired, memory_order_seq_cst)
333#define atomic_fetch_add(object, operand) \
334 atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
335#define atomic_fetch_and(object, operand) \
336 atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
337#define atomic_fetch_or(object, operand) \
338 atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
339#define atomic_fetch_sub(object, operand) \
340 atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
341#define atomic_fetch_xor(object, operand) \
342 atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
343#define atomic_load(object) \
344 atomic_load_explicit(object, memory_order_seq_cst)
345#define atomic_store(object, desired) \
346 atomic_store_explicit(object, desired, memory_order_seq_cst)
347
348/*
349 * 7.17.8 Atomic flag type and operations.
350 */
351
352typedef atomic_bool atomic_flag;
353
354#define ATOMIC_FLAG_INIT ATOMIC_VAR_INIT(0)
355
356#define atomic_flag_clear_explicit(object, order) \
357 atomic_store_explicit(object, 0, order)
358#define atomic_flag_test_and_set_explicit(object, order) \
359 atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
360
361#define atomic_flag_clear(object) \
362 atomic_flag_clear_explicit(object, memory_order_seq_cst)
363#define atomic_flag_test_and_set(object) \
364 atomic_flag_test_and_set_explicit(object, memory_order_seq_cst)
__ATOMIC_SEQ_CST
#define __ATOMIC_SEQ_CST
Definition stdatomic.h:116
memory_order
memory_order
Definition stdatomic.h:126
memory_order_consume
@ memory_order_consume
Definition stdatomic.h:128
memory_order_seq_cst
@ memory_order_seq_cst
Definition stdatomic.h:132
memory_order_release
@ memory_order_release
Definition stdatomic.h:130
memory_order_relaxed
@ memory_order_relaxed
Definition stdatomic.h:127
memory_order_acq_rel
@ memory_order_acq_rel
Definition stdatomic.h:131
memory_order_acquire
@ memory_order_acquire
Definition stdatomic.h:129
_Atomic
#define _Atomic(T)
Definition stdatomic.h:77
atomic_flag
atomic_bool atomic_flag
Definition stdatomic.h:352
__ATOMIC_RELEASE
#define __ATOMIC_RELEASE
Definition stdatomic.h:110
__ATOMIC_ACQUIRE
#define __ATOMIC_ACQUIRE
Definition stdatomic.h:107
__ATOMIC_CONSUME
#define __ATOMIC_CONSUME
Definition stdatomic.h:104
__ATOMIC_RELAXED
#define __ATOMIC_RELAXED
Definition stdatomic.h:101
__ATOMIC_ACQ_REL
#define __ATOMIC_ACQ_REL
Definition stdatomic.h:113
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