contrib/libcxxrt/atomic.h

   1
   2 #ifndef __has_builtin
   3 #define __has_builtin(x) 0
   4 #endif
   5 #ifndef __has_feature
   6 #define __has_feature(x) 0
   7 #endif
   8 /**
   9  * Swap macro that enforces a happens-before relationship with a corresponding
  10  * ATOMIC_LOAD.
  11  */
  12 #if __has_builtin(__c11_atomic_exchange)
  13 #define ATOMIC_SWAP(addr, val)\
  14         __c11_atomic_exchange(reinterpret_cast<_Atomic(__typeof__(val))*>(addr), val, __ATOMIC_ACQ_REL)
  15 #elif __has_builtin(__sync_swap)
  16 #define ATOMIC_SWAP(addr, val)\
  17         __sync_swap(addr, val)
  18 #else
  19 #define ATOMIC_SWAP(addr, val)\
  20         __sync_lock_test_and_set(addr, val)
  21 #endif
  22
  23 #if __has_builtin(__c11_atomic_load)
  24 #define ATOMIC_LOAD(addr)\
  25         __c11_atomic_load(reinterpret_cast<_Atomic(__typeof__(*addr))*>(addr), __ATOMIC_ACQUIRE)
  26 #else
  27 #define ATOMIC_LOAD(addr)\
  28         (__sync_synchronize(), *addr)
  29 #endif
  30