include/stdatomic.h

   1 /*-
   2  * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
   3  *                    David Chisnall <theraven@FreeBSD.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD$
  28  */
  29
  30 #ifndef _STDATOMIC_H_
  31 #define _STDATOMIC_H_
  32
  33 #include <sys/cdefs.h>
  34 #include <sys/_types.h>
  35
  36 #if __has_extension(c_atomic) || __has_extension(cxx_atomic)
  37 #define __CLANG_ATOMICS
  38 #elif __GNUC_PREREQ__(4, 7)
  39 #define __GNUC_ATOMICS
  40 #elif !defined(__GNUC__)
  41 #error "stdatomic.h does not support your compiler"
  42 #endif
  43
  44 #if !defined(__CLANG_ATOMICS)
  45 #define _Atomic(T)                      struct { volatile T __val; }
  46 #endif
  47
  48 /*
  49  * 7.17.2 Initialization.
  50  */
  51
  52 #if defined(__CLANG_ATOMICS)
  53 #define ATOMIC_VAR_INIT(value)          (value)
  54 #define atomic_init(obj, value)         __c11_atomic_init(obj, value)
  55 #else
  56 #define ATOMIC_VAR_INIT(value)          { .__val = (value) }
  57 #define atomic_init(obj, value)         ((void)((obj)->__val = (value)))
  58 #endif
  59
  60 /*
  61  * Clang and recent GCC both provide predefined macros for the memory
  62  * orderings.  If we are using a compiler that doesn't define them, use the
  63  * clang values - these will be ignored in the fallback path.
  64  */
  65
  66 #ifndef __ATOMIC_RELAXED
  67 #define __ATOMIC_RELAXED                0
  68 #endif
  69 #ifndef __ATOMIC_CONSUME
  70 #define __ATOMIC_CONSUME                1
  71 #endif
  72 #ifndef __ATOMIC_ACQUIRE
  73 #define __ATOMIC_ACQUIRE                2
  74 #endif
  75 #ifndef __ATOMIC_RELEASE
  76 #define __ATOMIC_RELEASE                3
  77 #endif
  78 #ifndef __ATOMIC_ACQ_REL
  79 #define __ATOMIC_ACQ_REL                4
  80 #endif
  81 #ifndef __ATOMIC_SEQ_CST
  82 #define __ATOMIC_SEQ_CST                5
  83 #endif
  84
  85 /*
  86  * 7.17.3 Order and consistency.
  87  *
  88  * The memory_order_* constants that denote the barrier behaviour of the
  89  * atomic operations.
  90  */
  91
  92 enum memory_order {
  93         memory_order_relaxed = __ATOMIC_RELAXED,
  94         memory_order_consume = __ATOMIC_CONSUME,
  95         memory_order_acquire = __ATOMIC_ACQUIRE,
  96         memory_order_release = __ATOMIC_RELEASE,
  97         memory_order_acq_rel = __ATOMIC_ACQ_REL,
  98         memory_order_seq_cst = __ATOMIC_SEQ_CST
  99 };
 100
 101 /*
 102  * 7.17.4 Fences.
 103  */
 104
 105 #ifdef __CLANG_ATOMICS
 106 #define atomic_thread_fence(order)      __c11_atomic_thread_fence(order)
 107 #define atomic_signal_fence(order)      __c11_atomic_signal_fence(order)
 108 #elif defined(__GNUC_ATOMICS)
 109 #define atomic_thread_fence(order)      __atomic_thread_fence(order)
 110 #define atomic_signal_fence(order)      __atomic_signal_fence(order)
 111 #else
 112 #define atomic_thread_fence(order)      ((void)(order), __sync_synchronize())
 113 #define atomic_signal_fence(order)      __extension__ ({                \
 114         (void)(order);                                                  \
 115         __asm volatile ("" ::: "memory");                               \
 116         (void)0;                                                        \
 117 })
 118 #endif
 119
 120 /*
 121  * 7.17.5 Lock-free property.
 122  */
 123
 124 #if defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)
 125 #define atomic_is_lock_free(obj) \
 126         __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
 127 #else
 128 #define atomic_is_lock_free(obj) \
 129         ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
 130 #endif
 131
 132 /*
 133  * 7.17.6 Atomic integer types.
 134  */
 135
 136 typedef _Atomic(_Bool)                  atomic_bool;
 137 typedef _Atomic(char)                   atomic_char;
 138 typedef _Atomic(signed char)            atomic_schar;
 139 typedef _Atomic(unsigned char)          atomic_uchar;
 140 typedef _Atomic(short)                  atomic_short;
 141 typedef _Atomic(unsigned short)         atomic_ushort;
 142 typedef _Atomic(int)                    atomic_int;
 143 typedef _Atomic(unsigned int)           atomic_uint;
 144 typedef _Atomic(long)                   atomic_long;
 145 typedef _Atomic(unsigned long)          atomic_ulong;
 146 typedef _Atomic(long long)              atomic_llong;
 147 typedef _Atomic(unsigned long long)     atomic_ullong;
 148 typedef _Atomic(__char16_t)             atomic_char16_t;
 149 typedef _Atomic(__char32_t)             atomic_char32_t;
 150 typedef _Atomic(___wchar_t)             atomic_wchar_t;
 151 typedef _Atomic(__int_least8_t)         atomic_int_least8_t;
 152 typedef _Atomic(__uint_least8_t)        atomic_uint_least8_t;
 153 typedef _Atomic(__int_least16_t)        atomic_int_least16_t;
 154 typedef _Atomic(__uint_least16_t)       atomic_uint_least16_t;
 155 typedef _Atomic(__int_least32_t)        atomic_int_least32_t;
 156 typedef _Atomic(__uint_least32_t)       atomic_uint_least32_t;
 157 typedef _Atomic(__int_least64_t)        atomic_int_least64_t;
 158 typedef _Atomic(__uint_least64_t)       atomic_uint_least64_t;
 159 typedef _Atomic(__int_fast8_t)          atomic_int_fast8_t;
 160 typedef _Atomic(__uint_fast8_t)         atomic_uint_fast8_t;
 161 typedef _Atomic(__int_fast16_t)         atomic_int_fast16_t;
 162 typedef _Atomic(__uint_fast16_t)        atomic_uint_fast16_t;
 163 typedef _Atomic(__int_fast32_t)         atomic_int_fast32_t;
 164 typedef _Atomic(__uint_fast32_t)        atomic_uint_fast32_t;
 165 typedef _Atomic(__int_fast64_t)         atomic_int_fast64_t;
 166 typedef _Atomic(__uint_fast64_t)        atomic_uint_fast64_t;
 167 typedef _Atomic(__intptr_t)             atomic_intptr_t;
 168 typedef _Atomic(__uintptr_t)            atomic_uintptr_t;
 169 typedef _Atomic(__size_t)               atomic_size_t;
 170 typedef _Atomic(__ptrdiff_t)            atomic_ptrdiff_t;
 171 typedef _Atomic(__intmax_t)             atomic_intmax_t;
 172 typedef _Atomic(__uintmax_t)            atomic_uintmax_t;
 173
 174 /*
 175  * 7.17.7 Operations on atomic types.
 176  */
 177
 178 /*
 179  * Compiler-specific operations.
 180  */
 181
 182 #if defined(__CLANG_ATOMICS)
 183 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 184     desired, success, failure)                                          \
 185         __c11_atomic_compare_exchange_strong(object, expected, desired, \
 186             success, failure)
 187 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 188     desired, success, failure)                                          \
 189         __c11_atomic_compare_exchange_weak(object, expected, desired,   \
 190             success, failure)
 191 #define atomic_exchange_explicit(object, desired, order)                \
 192         __c11_atomic_exchange(object, desired, order)
 193 #define atomic_fetch_add_explicit(object, operand, order)               \
 194         __c11_atomic_fetch_add(object, operand, order)
 195 #define atomic_fetch_and_explicit(object, operand, order)               \
 196         __c11_atomic_fetch_and(object, operand, order)
 197 #define atomic_fetch_or_explicit(object, operand, order)                \
 198         __c11_atomic_fetch_or(object, operand, order)
 199 #define atomic_fetch_sub_explicit(object, operand, order)               \
 200         __c11_atomic_fetch_sub(object, operand, order)
 201 #define atomic_fetch_xor_explicit(object, operand, order)               \
 202         __c11_atomic_fetch_xor(object, operand, order)
 203 #define atomic_load_explicit(object, order)                             \
 204         __c11_atomic_load(object, order)
 205 #define atomic_store_explicit(object, desired, order)                   \
 206         __c11_atomic_store(object, desired, order)
 207 #elif defined(__GNUC_ATOMICS)
 208 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 209     desired, success, failure)                                          \
 210         __atomic_compare_exchange_n(&(object)->__val, expected,         \
 211             desired, 0, success, failure)
 212 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 213     desired, success, failure)                                          \
 214         __atomic_compare_exchange_n(&(object)->__val, expected,         \
 215             desired, 1, success, failure)
 216 #define atomic_exchange_explicit(object, desired, order)                \
 217         __atomic_exchange_n(&(object)->__val, desired, order)
 218 #define atomic_fetch_add_explicit(object, operand, order)               \
 219         __atomic_fetch_add(&(object)->__val, operand, order)
 220 #define atomic_fetch_and_explicit(object, operand, order)               \
 221         __atomic_fetch_and(&(object)->__val, operand, order)
 222 #define atomic_fetch_or_explicit(object, operand, order)                \
 223         __atomic_fetch_or(&(object)->__val, operand, order)
 224 #define atomic_fetch_sub_explicit(object, operand, order)               \
 225         __atomic_fetch_sub(&(object)->__val, operand, order)
 226 #define atomic_fetch_xor_explicit(object, operand, order)               \
 227         __atomic_fetch_xor(&(object)->__val, operand, order)
 228 #define atomic_load_explicit(object, order)                             \
 229         __atomic_load_n(&(object)->__val, order)
 230 #define atomic_store_explicit(object, desired, order)                   \
 231         __atomic_store_n(&(object)->__val, desired, order)
 232 #else
 233 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 234     desired, success, failure)  __extension__ ({                        \
 235         __typeof__(expected) __ep = (expected);                         \
 236         __typeof__(*__ep) __e = *__ep;                                  \
 237         (void)(success); (void)(failure);                               \
 238         (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val,  \
 239             __e, desired)) == __e);                                     \
 240 })
 241 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 242     desired, success, failure)                                          \
 243         atomic_compare_exchange_strong_explicit(object, expected,       \
 244                 desired, success, failure)
 245 #if __has_builtin(__sync_swap)
 246 /* Clang provides a full-barrier atomic exchange - use it if available. */
 247 #define atomic_exchange_explicit(object, desired, order)                \
 248         ((void)(order), __sync_swap(&(object)->__val, desired))
 249 #else
 250 /*
 251  * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
 252  * practice it is usually a full barrier) so we need an explicit barrier before
 253  * it.
 254  */
 255 #define atomic_exchange_explicit(object, desired, order)                \
 256 __extension__ ({                                                        \
 257         __typeof__(object) __o = (object);                              \
 258         __typeof__(desired) __d = (desired);                            \
 259         (void)(order);                                                  \
 260         __sync_synchronize();                                           \
 261         __sync_lock_test_and_set(&(__o)->__val, __d);                   \
 262 })
 263 #endif
 264 #define atomic_fetch_add_explicit(object, operand, order)               \
 265         ((void)(order), __sync_fetch_and_add(&(object)->__val, operand))
 266 #define atomic_fetch_and_explicit(object, operand, order)               \
 267         ((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
 268 #define atomic_fetch_or_explicit(object, operand, order)                \
 269         ((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
 270 #define atomic_fetch_sub_explicit(object, operand, order)               \
 271         ((void)(order), __sync_fetch_and_sub(&(object)->__val, operand))
 272 #define atomic_fetch_xor_explicit(object, operand, order)               \
 273         ((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
 274 #define atomic_load_explicit(object, order)                             \
 275         ((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
 276 #define atomic_store_explicit(object, desired, order)                   \
 277         ((void)atomic_exchange_explicit(object, desired, order))
 278 #endif
 279
 280 /*
 281  * Convenience functions.
 282  */
 283
 284 #define atomic_compare_exchange_strong(object, expected, desired)       \
 285         atomic_compare_exchange_strong_explicit(object, expected,       \
 286             desired, memory_order_seq_cst, memory_order_seq_cst)
 287 #define atomic_compare_exchange_weak(object, expected, desired)         \
 288         atomic_compare_exchange_weak_explicit(object, expected,         \
 289             desired, memory_order_seq_cst, memory_order_seq_cst)
 290 #define atomic_exchange(object, desired)                                \
 291         atomic_exchange_explicit(object, desired, memory_order_seq_cst)
 292 #define atomic_fetch_add(object, operand)                               \
 293         atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
 294 #define atomic_fetch_and(object, operand)                               \
 295         atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
 296 #define atomic_fetch_or(object, operand)                                \
 297         atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
 298 #define atomic_fetch_sub(object, operand)                               \
 299         atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
 300 #define atomic_fetch_xor(object, operand)                               \
 301         atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
 302 #define atomic_load(object)                                             \
 303         atomic_load_explicit(object, memory_order_seq_cst)
 304 #define atomic_store(object, desired)                                   \
 305         atomic_store_explicit(object, desired, memory_order_seq_cst)
 306
 307 /*
 308  * 7.17.8 Atomic flag type and operations.
 309  */
 310
 311 typedef atomic_bool                     atomic_flag;
 312
 313 #define ATOMIC_FLAG_INIT                ATOMIC_VAR_INIT(0)
 314
 315 #define atomic_flag_clear_explicit(object, order)                       \
 316         atomic_store_explicit(object, 0, order)
 317 #define atomic_flag_test_and_set_explicit(object, order)                \
 318         atomic_exchange_explicit(object, 1, order)
 319
 320 #define atomic_flag_clear(object)                                       \
 321         atomic_flag_clear_explicit(object, memory_order_seq_cst)
 322 #define atomic_flag_test_and_set(object)                                \
 323         atomic_flag_test_and_set_explicit(object, memory_order_seq_cst)
 324
 325 #endif /* !_STDATOMIC_H_ */