1//===----------------------------------------------------------------------===//// 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#ifndef ATOMIC_SUPPORT_H 10#define ATOMIC_SUPPORT_H 11 12#include "__config" 13#include "memory" // for __libcpp_relaxed_load 14 15#if defined(__clang__) && __has_builtin(__atomic_load_n) \ 16 && __has_builtin(__atomic_store_n) \ 17 && __has_builtin(__atomic_add_fetch) \ 18 && __has_builtin(__atomic_exchange_n) \ 19 && __has_builtin(__atomic_compare_exchange_n) \ 20 && defined(__ATOMIC_RELAXED) \ 21 && defined(__ATOMIC_CONSUME) \ 22 && defined(__ATOMIC_ACQUIRE) \ 23 && defined(__ATOMIC_RELEASE) \ 24 && defined(__ATOMIC_ACQ_REL) \ 25 && defined(__ATOMIC_SEQ_CST) 26# define _LIBCPP_HAS_ATOMIC_BUILTINS 27#elif !defined(__clang__) && defined(_GNUC_VER) && _GNUC_VER >= 407 28# define _LIBCPP_HAS_ATOMIC_BUILTINS 29#endif 30 31#if !defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS) 32# if defined(_LIBCPP_WARNING) 33 _LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported") 34# else 35# warning Building libc++ without __atomic builtins is unsupported 36# endif 37#endif 38 39_LIBCPP_BEGIN_NAMESPACE_STD 40 41namespace { 42 43#if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS) 44 45enum __libcpp_atomic_order { 46 _AO_Relaxed = __ATOMIC_RELAXED, 47 _AO_Consume = __ATOMIC_CONSUME, 48 _AO_Acquire = __ATOMIC_ACQUIRE, 49 _AO_Release = __ATOMIC_RELEASE, 50 _AO_Acq_Rel = __ATOMIC_ACQ_REL, 51 _AO_Seq = __ATOMIC_SEQ_CST 52}; 53 54template <class _ValueType, class _FromType> 55inline _LIBCPP_INLINE_VISIBILITY 56void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, 57 int __order = _AO_Seq) 58{ 59 __atomic_store_n(__dest, __val, __order); 60} 61 62template <class _ValueType, class _FromType> 63inline _LIBCPP_INLINE_VISIBILITY 64void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) 65{ 66 __atomic_store_n(__dest, __val, _AO_Relaxed); 67} 68 69template <class _ValueType> 70inline _LIBCPP_INLINE_VISIBILITY 71_ValueType __libcpp_atomic_load(_ValueType const* __val, 72 int __order = _AO_Seq) 73{ 74 return __atomic_load_n(__val, __order); 75} 76 77template <class _ValueType, class _AddType> 78inline _LIBCPP_INLINE_VISIBILITY 79_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a, 80 int __order = _AO_Seq) 81{ 82 return __atomic_add_fetch(__val, __a, __order); 83} 84 85template <class _ValueType> 86inline _LIBCPP_INLINE_VISIBILITY 87_ValueType __libcpp_atomic_exchange(_ValueType* __target, 88 _ValueType __value, int __order = _AO_Seq) 89{ 90 return __atomic_exchange_n(__target, __value, __order); 91} 92 93template <class _ValueType> 94inline _LIBCPP_INLINE_VISIBILITY 95bool __libcpp_atomic_compare_exchange(_ValueType* __val, 96 _ValueType* __expected, _ValueType __after, 97 int __success_order = _AO_Seq, 98 int __fail_order = _AO_Seq) 99{ 100 return __atomic_compare_exchange_n(__val, __expected, __after, true, 101 __success_order, __fail_order); 102} 103 104#else // _LIBCPP_HAS_NO_THREADS 105 106enum __libcpp_atomic_order { 107 _AO_Relaxed, 108 _AO_Consume, 109 _AO_Acquire, 110 _AO_Release, 111 _AO_Acq_Rel, 112 _AO_Seq 113}; 114 115template <class _ValueType, class _FromType> 116inline _LIBCPP_INLINE_VISIBILITY 117void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, 118 int = 0) 119{ 120 *__dest = __val; 121} 122 123template <class _ValueType, class _FromType> 124inline _LIBCPP_INLINE_VISIBILITY 125void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) 126{ 127 *__dest = __val; 128} 129 130template <class _ValueType> 131inline _LIBCPP_INLINE_VISIBILITY 132_ValueType __libcpp_atomic_load(_ValueType const* __val, 133 int = 0) 134{ 135 return *__val; 136} 137 138template <class _ValueType, class _AddType> 139inline _LIBCPP_INLINE_VISIBILITY 140_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a, 141 int = 0) 142{ 143 return *__val += __a; 144} 145 146template <class _ValueType> 147inline _LIBCPP_INLINE_VISIBILITY 148_ValueType __libcpp_atomic_exchange(_ValueType* __target, 149 _ValueType __value, int __order = _AO_Seq) 150{ 151 _ValueType old = *__target; 152 *__target = __value; 153 return old; 154} 155 156template <class _ValueType> 157inline _LIBCPP_INLINE_VISIBILITY 158bool __libcpp_atomic_compare_exchange(_ValueType* __val, 159 _ValueType* __expected, _ValueType __after, 160 int = 0, int = 0) 161{ 162 if (*__val == *__expected) { 163 *__val = __after; 164 return true; 165 } 166 *__expected = *__val; 167 return false; 168} 169 170#endif // _LIBCPP_HAS_NO_THREADS 171 172} // end namespace 173 174_LIBCPP_END_NAMESPACE_STD 175 176#endif // ATOMIC_SUPPORT_H 177