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_feature(cxx_atomic)
  37 #define __CLANG_ATOMICS
  38 #elif defined(__GNUC__)
  39 #define __GNUC_ATOMICS
  40 #else
  41 #error "stdatomic.h does not support your compiler"
  42 #endif
  43
  44 #ifdef __GNUC_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)                 __atomic_init(obj, value)
  55 #elif defined(__GNUC_ATOMICS)
  56 #define ATOMIC_VAR_INIT(value)                  { .__val = (value) }
  57 #define atomic_init(obj, value)                 (obj = ATOMIC_VAR_INIT(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 #if defined(__CLANG_ATOMICS)
 106 #define atomic_thread_fence(order)      __atomic_thread_fence(order)
 107 #elif defined(__GNUC_ATOMICS)
 108 #define atomic_thread_fence(order)      __sync_synchronize()
 109 #endif
 110 #define atomic_signal_fence(order)      __asm volatile ("" : : : "memory");
 111
 112 /*
 113  * 7.17.5 Lock-free property.
 114  */
 115
 116 #if defined(__CLANG_ATOMICS)
 117 #define atomic_is_lock_free(obj)        __atomic_is_lock_free(obj)
 118 #elif defined(__GNUC_ATOMICS)
 119 #define atomic_is_lock_free(obj)        (sizeof((obj->__val)) <= sizeof(void *))
 120 #endif
 121
 122 /*
 123  * 7.17.6 Atomic integer types.
 124  */
 125
 126 typedef _Atomic(_Bool)                  atomic_bool;
 127 typedef _Atomic(char)                   atomic_char;
 128 typedef _Atomic(signed char)            atomic_schar;
 129 typedef _Atomic(unsigned char)          atomic_uchar;
 130 typedef _Atomic(short)                  atomic_short;
 131 typedef _Atomic(unsigned short)         atomic_ushort;
 132 typedef _Atomic(int)                    atomic_int;
 133 typedef _Atomic(unsigned int)           atomic_uint;
 134 typedef _Atomic(long)                   atomic_long;
 135 typedef _Atomic(unsigned long)          atomic_ulong;
 136 typedef _Atomic(long long)              atomic_llong;
 137 typedef _Atomic(unsigned long long)     atomic_ullong;
 138 #if 0
 139 typedef _Atomic(__char16_t)             atomic_char16_t;
 140 typedef _Atomic(__char32_t)             atomic_char32_t;
 141 #endif
 142 typedef _Atomic(__wchar_t)              atomic_wchar_t;
 143 typedef _Atomic(__int_least8_t)         atomic_int_least8_t;
 144 typedef _Atomic(__uint_least8_t)        atomic_uint_least8_t;
 145 typedef _Atomic(__int_least16_t)        atomic_int_least16_t;
 146 typedef _Atomic(__uint_least16_t)       atomic_uint_least16_t;
 147 typedef _Atomic(__int_least32_t)        atomic_int_least32_t;
 148 typedef _Atomic(__uint_least32_t)       atomic_uint_least32_t;
 149 typedef _Atomic(__int_least64_t)        atomic_int_least64_t;
 150 typedef _Atomic(__uint_least64_t)       atomic_uint_least64_t;
 151 typedef _Atomic(__int_fast8_t)          atomic_int_fast8_t;
 152 typedef _Atomic(__uint_fast8_t)         atomic_uint_fast8_t;
 153 typedef _Atomic(__int_fast16_t)         atomic_int_fast16_t;
 154 typedef _Atomic(__uint_fast16_t)        atomic_uint_fast16_t;
 155 typedef _Atomic(__int_fast32_t)         atomic_int_fast32_t;
 156 typedef _Atomic(__uint_fast32_t)        atomic_uint_fast32_t;
 157 typedef _Atomic(__int_fast64_t)         atomic_int_fast64_t;
 158 typedef _Atomic(__uint_fast64_t)        atomic_uint_fast64_t;
 159 typedef _Atomic(__intptr_t)             atomic_intptr_t;
 160 typedef _Atomic(__uintptr_t)            atomic_uintptr_t;
 161 typedef _Atomic(__size_t)               atomic_size_t;
 162 typedef _Atomic(__ptrdiff_t)            atomic_ptrdiff_t;
 163 typedef _Atomic(__intmax_t)             atomic_intmax_t;
 164 typedef _Atomic(__uintmax_t)            atomic_uintmax_t;
 165
 166 /*
 167  * 7.17.7 Operations on atomic types.
 168  */
 169
 170 /*
 171  * Compiler-specific operations.
 172  */
 173
 174 #if defined(__CLANG_ATOMICS)
 175 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 176     desired, success, failure)                                          \
 177         __atomic_compare_exchange_strong(object, expected, desired,     \
 178             success, failure)
 179 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 180     desired, success, failure)                                          \
 181         __atomic_compare_exchange_weak(object, expected, desired,       \
 182             success, failure)
 183 #define atomic_exchange_explicit(object, desired, order)                \
 184         __atomic_exchange(object, desired, order)
 185 #define atomic_fetch_add_explicit(object, operand, order)               \
 186         __atomic_fetch_add(object, operand, order)
 187 #define atomic_fetch_and_explicit(object, operand, order)               \
 188         __atomic_fetch_and(object, operand, order)
 189 #define atomic_fetch_or_explicit(object, operand, order)                \
 190         __atomic_fetch_or(object, operand, order)
 191 #define atomic_fetch_sub_explicit(object, operand, order)               \
 192         __atomic_fetch_sub(object, operand, order)
 193 #define atomic_fetch_xor_explicit(object, operand, order)               \
 194         __atomic_fetch_xor(object, operand, order)
 195 #define atomic_load_explicit(object, order)                             \
 196         __atomic_load(object, order)
 197 #define atomic_store_explicit(object, desired, order)                   \
 198         __atomic_store(object, desired, order)
 199 #elif defined(__GNUC_ATOMICS)
 200 #define atomic_compare_exchange_strong_explicit(object, expected,       \
 201     desired, success, failure) ({                                       \
 202         __typeof__((object)->__val) __v;                                \
 203         __v =                                                           \
 204         __sync_val_compare_and_swap((__typeof(&((object)->__val)))object,\
 205                 *expected, desired);                                    \
 206         *expected = __v;                                                \
 207         (*expected == __v);                                             \
 208         })
 209
 210 #define atomic_compare_exchange_weak_explicit(object, expected,         \
 211     desired, success, failure)                                          \
 212         atomic_compare_exchange_strong_explicit(object, expected,       \
 213                 desired, success, failure)
 214 #if __has_builtin(__sync_swap)
 215 /* Clang provides a full-barrier atomic exchange - use it if available. */
 216 #define atomic_exchange_explicit(object, desired, order)                \
 217         __sync_swap(&(object)->value, desired)
 218 #else
 219 /*
 220  * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
 221  * practice it is usually a full barrier) so we need an explicit barrier after
 222  * it.
 223  */
 224 #define atomic_exchange_explicit(object, desired, order) ({             \
 225         __typeof__((object)->__val) __v;                                \
 226         __v = __sync_lock_test_and_set(object, desired);                \
 227         __sync_synchronize();                                           \
 228         __v;                                                            \
 229 })
 230 #endif
 231 #define atomic_fetch_add_explicit(object, operand, order)               \
 232         __sync_fetch_and_add(&(object)->__val, operand)
 233 #define atomic_fetch_and_explicit(object, operand, order)               \
 234         __sync_fetch_and_and(&(object)->__val, operand)
 235 #define atomic_fetch_or_explicit(object, operand, order)                \
 236         __sync_fetch_and_or(&(object)->__val, operand)
 237 #define atomic_fetch_sub_explicit(object, operand, order)               \
 238         __sync_fetch_and_sub(&(object)->__val, operand)
 239 #define atomic_fetch_xor_explicit(object, operand, order)               \
 240         __sync_fetch_and_xor(&(object)->__val, operand)
 241 #define atomic_load_explicit(object, order)                             \
 242         __sync_fetch_and_add(&(object)->__val, 0)
 243 #define atomic_store_explicit(object, desired, order) do {              \
 244         __sync_synchronize();                                           \
 245         (object)->__val = (desired);                                    \
 246         __sync_synchronize();                                           \
 247 } while (0)
 248 #endif
 249
 250 /*
 251  * Convenience functions.
 252  */
 253
 254 #define atomic_compare_exchange_strong(object, expected, desired)       \
 255         atomic_compare_exchange_strong_explicit(object, expected,       \
 256             desired, memory_order_seq_cst, memory_order_seq_cst)
 257 #define atomic_compare_exchange_weak(object, expected, desired)         \
 258         atomic_compare_exchange_weak_explicit(object, expected,         \
 259             desired, memory_order_seq_cst, memory_order_seq_cst)
 260 #define atomic_exchange(object, desired)                                \
 261         atomic_exchange_explicit(object, desired, memory_order_seq_cst)
 262 #define atomic_fetch_add(object, operand)                               \
 263         atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
 264 #define atomic_fetch_and(object, operand)                               \
 265         atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
 266 #define atomic_fetch_or(object, operand)                                \
 267         atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
 268 #define atomic_fetch_sub(object, operand)                               \
 269         atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
 270 #define atomic_fetch_xor(object, operand)                               \
 271         atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
 272 #define atomic_load(object)                                             \
 273         atomic_load_explicit(object, memory_order_seq_cst)
 274 #define atomic_store(object, desired)                                   \
 275         atomic_store_explicit(object, desired, memory_order_seq_cst)
 276
 277 /*
 278  * 7.17.8 Atomic flag type and operations.
 279  */
 280
 281 typedef atomic_bool             atomic_flag;
 282
 283 #define ATOMIC_FLAG_INIT        ATOMIC_VAR_INIT(0)
 284
 285 #define atomic_flag_clear_explicit(object, order)                       \
 286         atomic_store_explicit(object, 0, order)
 287 #define atomic_flag_test_and_set_explicit(object, order)                \
 288         atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
 289
 290 #define atomic_flag_clear(object)                                       \
 291         atomic_flag_clear_explicit(object, 0, memory_order_seq_cst)
 292 #define atomic_flag_test_and_set(object)                                \
 293         atomic_flag_test_and_set_explicit(object, 0, 1,                 \
 294             memory_order_seq_cst, memory_order_seq_cst)
 295
 296 #endif /* !_STDATOMIC_H_ */