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) && __has_builtin(__atomic_store_n) && \
16 __has_builtin(__atomic_add_fetch) && __has_builtin(__atomic_exchange_n) && \
17 __has_builtin(__atomic_compare_exchange_n) && defined(__ATOMIC_RELAXED) && defined(__ATOMIC_CONSUME) && \
18 defined(__ATOMIC_ACQUIRE) && defined(__ATOMIC_RELEASE) && defined(__ATOMIC_ACQ_REL) && defined(__ATOMIC_SEQ_CST)
19 # define _LIBCPP_HAS_ATOMIC_BUILTINS
20 #elif defined(_LIBCPP_COMPILER_GCC)
21 # define _LIBCPP_HAS_ATOMIC_BUILTINS
22 #endif
23
24 #if !defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
25 # if defined(_LIBCPP_WARNING)
26 _LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported")
27 # else
28 # warning Building libc++ without __atomic builtins is unsupported
29 # endif
30 #endif
31
32 _LIBCPP_BEGIN_NAMESPACE_STD
33
34 namespace {
35
36 #if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
37
38 enum __libcpp_atomic_order {
39 _AO_Relaxed = __ATOMIC_RELAXED,
40 _AO_Consume = __ATOMIC_CONSUME,
41 _AO_Acquire = __ATOMIC_ACQUIRE,
42 _AO_Release = __ATOMIC_RELEASE,
43 _AO_Acq_Rel = __ATOMIC_ACQ_REL,
44 _AO_Seq = __ATOMIC_SEQ_CST
45 };
46
47 template <class _ValueType, class _FromType>
48 inline _LIBCPP_HIDE_FROM_ABI void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, int __order = _AO_Seq) {
49 __atomic_store_n(__dest, __val, __order);
50 }
51
52 template <class _ValueType, class _FromType>
__libcpp_relaxed_store(_ValueType * __dest,_FromType __val)53 inline _LIBCPP_HIDE_FROM_ABI void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) {
54 __atomic_store_n(__dest, __val, _AO_Relaxed);
55 }
56
57 template <class _ValueType>
58 inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_atomic_load(_ValueType const* __val, int __order = _AO_Seq) {
59 return __atomic_load_n(__val, __order);
60 }
61
62 template <class _ValueType, class _AddType>
63 inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a, int __order = _AO_Seq) {
64 return __atomic_add_fetch(__val, __a, __order);
65 }
66
67 template <class _ValueType>
68 inline _LIBCPP_HIDE_FROM_ABI _ValueType
69 __libcpp_atomic_exchange(_ValueType* __target, _ValueType __value, int __order = _AO_Seq) {
70 return __atomic_exchange_n(__target, __value, __order);
71 }
72
73 template <class _ValueType>
74 inline _LIBCPP_HIDE_FROM_ABI bool __libcpp_atomic_compare_exchange(
75 _ValueType* __val,
76 _ValueType* __expected,
77 _ValueType __after,
78 int __success_order = _AO_Seq,
79 int __fail_order = _AO_Seq) {
80 return __atomic_compare_exchange_n(__val, __expected, __after, true, __success_order, __fail_order);
81 }
82
83 #else // _LIBCPP_HAS_NO_THREADS
84
85 enum __libcpp_atomic_order { _AO_Relaxed, _AO_Consume, _AO_Acquire, _AO_Release, _AO_Acq_Rel, _AO_Seq };
86
87 template <class _ValueType, class _FromType>
88 inline _LIBCPP_HIDE_FROM_ABI void __libcpp_atomic_store(_ValueType* __dest, _FromType __val, int = 0) {
89 *__dest = __val;
90 }
91
92 template <class _ValueType, class _FromType>
93 inline _LIBCPP_HIDE_FROM_ABI void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val) {
94 *__dest = __val;
95 }
96
97 template <class _ValueType>
98 inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_atomic_load(_ValueType const* __val, int = 0) {
99 return *__val;
100 }
101
102 template <class _ValueType, class _AddType>
103 inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a, int = 0) {
104 return *__val += __a;
105 }
106
107 template <class _ValueType>
108 inline _LIBCPP_HIDE_FROM_ABI _ValueType
109 __libcpp_atomic_exchange(_ValueType* __target, _ValueType __value, int = _AO_Seq) {
110 _ValueType old = *__target;
111 *__target = __value;
112 return old;
113 }
114
115 template <class _ValueType>
116 inline _LIBCPP_HIDE_FROM_ABI bool
117 __libcpp_atomic_compare_exchange(_ValueType* __val, _ValueType* __expected, _ValueType __after, int = 0, int = 0) {
118 if (*__val == *__expected) {
119 *__val = __after;
120 return true;
121 }
122 *__expected = *__val;
123 return false;
124 }
125
126 #endif // _LIBCPP_HAS_NO_THREADS
127
128 } // end namespace
129
130 _LIBCPP_END_NAMESPACE_STD
131
132 #endif // ATOMIC_SUPPORT_H
133