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(_LIBCPP_COMPILER_GCC) 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 41 namespace { 42 43 #if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS) 44 45 enum __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 54 template <class _ValueType, class _FromType> 55 inline _LIBCPP_INLINE_VISIBILITY 56 void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, 57 int __order = _AO_Seq) 58 { 59 __atomic_store_n(__dest, __val, __order); 60 } 61 62 template <class _ValueType, class _FromType> 63 inline _LIBCPP_INLINE_VISIBILITY 64 void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) 65 { 66 __atomic_store_n(__dest, __val, _AO_Relaxed); 67 } 68 69 template <class _ValueType> 70 inline _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 77 template <class _ValueType, class _AddType> 78 inline _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 85 template <class _ValueType> 86 inline _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 93 template <class _ValueType> 94 inline _LIBCPP_INLINE_VISIBILITY 95 bool __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 105 106 enum __libcpp_atomic_order { 107 _AO_Relaxed, 108 _AO_Consume, 109 _AO_Acquire, 110 _AO_Release, 111 _AO_Acq_Rel, 112 _AO_Seq 113 }; 114 115 template <class _ValueType, class _FromType> 116 inline _LIBCPP_INLINE_VISIBILITY 117 void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, 118 int = 0) 119 { 120 *__dest = __val; 121 } 122 123 template <class _ValueType, class _FromType> 124 inline _LIBCPP_INLINE_VISIBILITY 125 void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) 126 { 127 *__dest = __val; 128 } 129 130 template <class _ValueType> 131 inline _LIBCPP_INLINE_VISIBILITY 132 _ValueType __libcpp_atomic_load(_ValueType const* __val, 133 int = 0) 134 { 135 return *__val; 136 } 137 138 template <class _ValueType, class _AddType> 139 inline _LIBCPP_INLINE_VISIBILITY 140 _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a, 141 int = 0) 142 { 143 return *__val += __a; 144 } 145 146 template <class _ValueType> 147 inline _LIBCPP_INLINE_VISIBILITY 148 _ValueType __libcpp_atomic_exchange(_ValueType* __target, 149 _ValueType __value, int = _AO_Seq) 150 { 151 _ValueType old = *__target; 152 *__target = __value; 153 return old; 154 } 155 156 template <class _ValueType> 157 inline _LIBCPP_INLINE_VISIBILITY 158 bool __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