1//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===// 2// 3// This file is distributed under the University of Illinois Open Source 4// License. See LICENSE.TXT for details. 5// 6//===----------------------------------------------------------------------===// 7// 8// This file is a part of ThreadSanitizer/AddressSanitizer runtime. 9// Not intended for direct inclusion. Include sanitizer_atomic.h. 10// 11//===----------------------------------------------------------------------===// 12 13#ifndef SANITIZER_ATOMIC_CLANG_H 14#define SANITIZER_ATOMIC_CLANG_H 15 16#if defined(__i386__) || defined(__x86_64__) 17# include "sanitizer_atomic_clang_x86.h" 18#else 19# include "sanitizer_atomic_clang_other.h" 20#endif 21 22namespace __sanitizer { 23 24// We would like to just use compiler builtin atomic operations 25// for loads and stores, but they are mostly broken in clang: 26// - they lead to vastly inefficient code generation 27// (http://llvm.org/bugs/show_bug.cgi?id=17281) 28// - 64-bit atomic operations are not implemented on x86_32 29// (http://llvm.org/bugs/show_bug.cgi?id=15034) 30// - they are not implemented on ARM 31// error: undefined reference to '__atomic_load_4' 32 33// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html 34// for mappings of the memory model to different processors. 35 36INLINE void atomic_signal_fence(memory_order) { 37 __asm__ __volatile__("" ::: "memory"); 38} 39 40INLINE void atomic_thread_fence(memory_order) { 41 __sync_synchronize(); 42} 43 44template<typename T> 45INLINE typename T::Type atomic_fetch_add(volatile T *a, 46 typename T::Type v, memory_order mo) { 47 (void)mo; 48 DCHECK(!((uptr)a % sizeof(*a))); 49 return __sync_fetch_and_add(&a->val_dont_use, v); 50} 51 52template<typename T> 53INLINE typename T::Type atomic_fetch_sub(volatile T *a, 54 typename T::Type v, memory_order mo) { 55 (void)mo; 56 DCHECK(!((uptr)a % sizeof(*a))); 57 return __sync_fetch_and_add(&a->val_dont_use, -v); 58} 59 60template<typename T> 61INLINE typename T::Type atomic_exchange(volatile T *a, 62 typename T::Type v, memory_order mo) { 63 DCHECK(!((uptr)a % sizeof(*a))); 64 if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst)) 65 __sync_synchronize(); 66 v = __sync_lock_test_and_set(&a->val_dont_use, v); 67 if (mo == memory_order_seq_cst) 68 __sync_synchronize(); 69 return v; 70} 71 72template<typename T> 73INLINE bool atomic_compare_exchange_strong(volatile T *a, 74 typename T::Type *cmp, 75 typename T::Type xchg, 76 memory_order mo) { 77 typedef typename T::Type Type; 78 Type cmpv = *cmp; 79 Type prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg); 80 if (prev == cmpv) 81 return true; 82 *cmp = prev; 83 return false; 84} 85 86template<typename T> 87INLINE bool atomic_compare_exchange_weak(volatile T *a, 88 typename T::Type *cmp, 89 typename T::Type xchg, 90 memory_order mo) { 91 return atomic_compare_exchange_strong(a, cmp, xchg, mo); 92} 93 94} // namespace __sanitizer 95 96#undef ATOMIC_ORDER 97 98#endif // SANITIZER_ATOMIC_CLANG_H 99