1//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file is a part of ThreadSanitizer/AddressSanitizer runtime. 10// Not intended for direct inclusion. Include sanitizer_atomic.h. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef SANITIZER_ATOMIC_CLANG_H 15#define SANITIZER_ATOMIC_CLANG_H 16 17#if defined(__i386__) || defined(__x86_64__) 18# include "sanitizer_atomic_clang_x86.h" 19#else 20# include "sanitizer_atomic_clang_other.h" 21#endif 22 23namespace __sanitizer { 24 25// We would like to just use compiler builtin atomic operations 26// for loads and stores, but they are mostly broken in clang: 27// - they lead to vastly inefficient code generation 28// (http://llvm.org/bugs/show_bug.cgi?id=17281) 29// - 64-bit atomic operations are not implemented on x86_32 30// (http://llvm.org/bugs/show_bug.cgi?id=15034) 31// - they are not implemented on ARM 32// error: undefined reference to '__atomic_load_4' 33 34// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html 35// for mappings of the memory model to different processors. 36 37INLINE void atomic_signal_fence(memory_order) { 38 __asm__ __volatile__("" ::: "memory"); 39} 40 41INLINE void atomic_thread_fence(memory_order) { 42 __sync_synchronize(); 43} 44 45template<typename T> 46INLINE typename T::Type atomic_fetch_add(volatile T *a, 47 typename T::Type v, memory_order mo) { 48 (void)mo; 49 DCHECK(!((uptr)a % sizeof(*a))); 50 return __sync_fetch_and_add(&a->val_dont_use, v); 51} 52 53template<typename T> 54INLINE typename T::Type atomic_fetch_sub(volatile T *a, 55 typename T::Type v, memory_order mo) { 56 (void)mo; 57 DCHECK(!((uptr)a % sizeof(*a))); 58 return __sync_fetch_and_add(&a->val_dont_use, -v); 59} 60 61template<typename T> 62INLINE typename T::Type atomic_exchange(volatile T *a, 63 typename T::Type v, memory_order mo) { 64 DCHECK(!((uptr)a % sizeof(*a))); 65 if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst)) 66 __sync_synchronize(); 67 v = __sync_lock_test_and_set(&a->val_dont_use, v); 68 if (mo == memory_order_seq_cst) 69 __sync_synchronize(); 70 return v; 71} 72 73template <typename T> 74INLINE bool atomic_compare_exchange_strong(volatile T *a, 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; 80 prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg); 81 if (prev == cmpv) 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// This include provides explicit template instantiations for atomic_uint64_t 97// on MIPS32, which does not directly support 8 byte atomics. It has to 98// proceed the template definitions above. 99#if defined(_MIPS_SIM) && defined(_ABIO32) 100 #include "sanitizer_atomic_clang_mips.h" 101#endif 102 103#undef ATOMIC_ORDER 104 105#endif // SANITIZER_ATOMIC_CLANG_H 106