1 //===-- sanitizer_atomic_clang_other.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_OTHER_H 16 #define SANITIZER_ATOMIC_CLANG_OTHER_H 17 18 namespace __sanitizer { 19 20 INLINE void proc_yield(int cnt) { 21 __asm__ __volatile__("" ::: "memory"); 22 } 23 24 template<typename T> 25 INLINE typename T::Type atomic_load( 26 const volatile T *a, memory_order mo) { 27 DCHECK(mo & (memory_order_relaxed | memory_order_consume 28 | memory_order_acquire | memory_order_seq_cst)); 29 DCHECK(!((uptr)a % sizeof(*a))); 30 typename T::Type v; 31 32 if (sizeof(*a) < 8 || sizeof(void*) == 8) { 33 // Assume that aligned loads are atomic. 34 if (mo == memory_order_relaxed) { 35 v = a->val_dont_use; 36 } else if (mo == memory_order_consume) { 37 // Assume that processor respects data dependencies 38 // (and that compiler won't break them). 39 __asm__ __volatile__("" ::: "memory"); 40 v = a->val_dont_use; 41 __asm__ __volatile__("" ::: "memory"); 42 } else if (mo == memory_order_acquire) { 43 __asm__ __volatile__("" ::: "memory"); 44 v = a->val_dont_use; 45 __sync_synchronize(); 46 } else { // seq_cst 47 // E.g. on POWER we need a hw fence even before the store. 48 __sync_synchronize(); 49 v = a->val_dont_use; 50 __sync_synchronize(); 51 } 52 } else { 53 // 64-bit load on 32-bit platform. 54 // Gross, but simple and reliable. 55 // Assume that it is not in read-only memory. 56 v = __sync_fetch_and_add( 57 const_cast<typename T::Type volatile *>(&a->val_dont_use), 0); 58 } 59 return v; 60 } 61 62 template<typename T> 63 INLINE void atomic_store(volatile T *a, typename T::Type v, memory_order mo) { 64 DCHECK(mo & (memory_order_relaxed | memory_order_release 65 | memory_order_seq_cst)); 66 DCHECK(!((uptr)a % sizeof(*a))); 67 68 if (sizeof(*a) < 8 || sizeof(void*) == 8) { 69 // Assume that aligned loads are atomic. 70 if (mo == memory_order_relaxed) { 71 a->val_dont_use = v; 72 } else if (mo == memory_order_release) { 73 __sync_synchronize(); 74 a->val_dont_use = v; 75 __asm__ __volatile__("" ::: "memory"); 76 } else { // seq_cst 77 __sync_synchronize(); 78 a->val_dont_use = v; 79 __sync_synchronize(); 80 } 81 } else { 82 // 64-bit store on 32-bit platform. 83 // Gross, but simple and reliable. 84 typename T::Type cmp = a->val_dont_use; 85 typename T::Type cur; 86 for (;;) { 87 cur = __sync_val_compare_and_swap(&a->val_dont_use, cmp, v); 88 if (cmp == v) 89 break; 90 cmp = cur; 91 } 92 } 93 } 94 95 } // namespace __sanitizer 96 97 #endif // #ifndef SANITIZER_ATOMIC_CLANG_OTHER_H 98
