1 //===----------------------------------------------------------------------===////
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===////
9
10 #ifndef ATOMIC_SUPPORT_H
11 #define ATOMIC_SUPPORT_H
12
13 #include "__config"
14 #include "memory" // for __libcpp_relaxed_load
15
16 #if defined(__clang__) && __has_builtin(__atomic_load_n) \
17 && __has_builtin(__atomic_store_n) \
18 && __has_builtin(__atomic_add_fetch) \
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_MSVC)
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
__libcpp_relaxed_store(_ValueType * __dest,_FromType __val)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 bool __libcpp_atomic_compare_exchange(_ValueType* __val,
88 _ValueType* __expected, _ValueType __after,
89 int __success_order = _AO_Seq,
90 int __fail_order = _AO_Seq)
91 {
92 return __atomic_compare_exchange_n(__val, __expected, __after, true,
93 __success_order, __fail_order);
94 }
95
96 #else // _LIBCPP_HAS_NO_THREADS
97
98 enum __libcpp_atomic_order {
99 _AO_Relaxed,
100 _AO_Consume,
101 _AO_Acquire,
102 _AO_Release,
103 _AO_Acq_Rel,
104 _AO_Seq
105 };
106
107 template <class _ValueType, class _FromType>
108 inline _LIBCPP_INLINE_VISIBILITY
109 void __libcpp_atomic_store(_ValueType* __dest, _FromType __val,
110 int = 0)
111 {
112 *__dest = __val;
113 }
114
115 template <class _ValueType, class _FromType>
116 inline _LIBCPP_INLINE_VISIBILITY
117 void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val)
118 {
119 *__dest = __val;
120 }
121
122 template <class _ValueType>
123 inline _LIBCPP_INLINE_VISIBILITY
124 _ValueType __libcpp_atomic_load(_ValueType const* __val,
125 int = 0)
126 {
127 return *__val;
128 }
129
130 template <class _ValueType, class _AddType>
131 inline _LIBCPP_INLINE_VISIBILITY
132 _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
133 int = 0)
134 {
135 return *__val += __a;
136 }
137
138 template <class _ValueType>
139 inline _LIBCPP_INLINE_VISIBILITY
140 bool __libcpp_atomic_compare_exchange(_ValueType* __val,
141 _ValueType* __expected, _ValueType __after,
142 int = 0, int = 0)
143 {
144 if (*__val == *__expected) {
145 *__val = __after;
146 return true;
147 }
148 *__expected = *__val;
149 return false;
150 }
151
152 #endif // _LIBCPP_HAS_NO_THREADS
153
154 } // end namespace
155
156 _LIBCPP_END_NAMESPACE_STD
157
158 #endif // ATOMIC_SUPPORT_H
159