1//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of ThreadSanitizer/AddressSanitizer runtime. 11// Not intended for direct inclusion. Include sanitizer_atomic.h. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef SANITIZER_ATOMIC_CLANG_H 16#define SANITIZER_ATOMIC_CLANG_H 17 18#if defined(__i386__) || defined(__x86_64__) 19# include "sanitizer_atomic_clang_x86.h" 20#else 21# include "sanitizer_atomic_clang_other.h" 22#endif 23 24namespace __sanitizer { 25 26// We would like to just use compiler builtin atomic operations 27// for loads and stores, but they are mostly broken in clang: 28// - they lead to vastly inefficient code generation 29// (http://llvm.org/bugs/show_bug.cgi?id=17281) 30// - 64-bit atomic operations are not implemented on x86_32 31// (http://llvm.org/bugs/show_bug.cgi?id=15034) 32// - they are not implemented on ARM 33// error: undefined reference to '__atomic_load_4' 34 35// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html 36// for mappings of the memory model to different processors. 37 38INLINE void atomic_signal_fence(memory_order) { 39 __asm__ __volatile__("" ::: "memory"); 40} 41 42INLINE void atomic_thread_fence(memory_order) { 43 __sync_synchronize(); 44} 45 46template<typename T> 47INLINE typename T::Type atomic_fetch_add(volatile T *a, 48 typename T::Type v, memory_order mo) { 49 (void)mo; 50 DCHECK(!((uptr)a % sizeof(*a))); 51 return __sync_fetch_and_add(&a->val_dont_use, v); 52} 53 54template<typename T> 55INLINE typename T::Type atomic_fetch_sub(volatile T *a, 56 typename T::Type v, memory_order mo) { 57 (void)mo; 58 DCHECK(!((uptr)a % sizeof(*a))); 59 return __sync_fetch_and_add(&a->val_dont_use, -v); 60} 61 62template<typename T> 63INLINE typename T::Type atomic_exchange(volatile T *a, 64 typename T::Type v, memory_order mo) { 65 DCHECK(!((uptr)a % sizeof(*a))); 66 if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst)) 67 __sync_synchronize(); 68 v = __sync_lock_test_and_set(&a->val_dont_use, v); 69 if (mo == memory_order_seq_cst) 70 __sync_synchronize(); 71 return v; 72} 73 74template<typename T> 75INLINE bool atomic_compare_exchange_strong(volatile T *a, 76 typename T::Type *cmp, 77 typename T::Type xchg, 78 memory_order mo) { 79 typedef typename T::Type Type; 80 Type cmpv = *cmp; 81 Type prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg); 82 if (prev == cmpv) 83 return true; 84 *cmp = prev; 85 return false; 86} 87 88template<typename T> 89INLINE bool atomic_compare_exchange_weak(volatile T *a, 90 typename T::Type *cmp, 91 typename T::Type xchg, 92 memory_order mo) { 93 return atomic_compare_exchange_strong(a, cmp, xchg, mo); 94} 95 96} // namespace __sanitizer 97 98#undef ATOMIC_ORDER 99 100#endif // SANITIZER_ATOMIC_CLANG_H 101