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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// Helper to suppress warnings related to 8-byte atomic accesses when the target
18// is 32-bit AIX (where such accesses use libatomic).
19#if defined(_AIX) && !defined(__powerpc64__) && defined(__clang__)
20# define SANITIZER_IGNORE_ATOMIC_ALIGNMENT_BEGIN \
21 _Pragma("clang diagnostic push") \
22 _Pragma("clang diagnostic ignored \"-Watomic-alignment\"")
23# define SANITIZER_IGNORE_ATOMIC_ALIGNMENT_END _Pragma("clang diagnostic pop")
24#else
25# define SANITIZER_IGNORE_ATOMIC_ALIGNMENT_BEGIN
26# define SANITIZER_IGNORE_ATOMIC_ALIGNMENT_END
27#endif
28
29namespace __sanitizer {
30
31// We use the compiler builtin atomic operations for loads and stores, which
32// generates correct code for all architectures, but may require libatomic
33// on platforms where e.g. 64-bit atomics are not supported natively.
34
35// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
36// for mappings of the memory model to different processors.
37
38inline void atomic_signal_fence(memory_order mo) { __atomic_signal_fence(mo); }
39
40inline void atomic_thread_fence(memory_order mo) { __atomic_thread_fence(mo); }
41
42inline void proc_yield(int cnt) {
43 __asm__ __volatile__("" ::: "memory");
44#if defined(__i386__) || defined(__x86_64__)
45 for (int i = 0; i < cnt; i++) __asm__ __volatile__("pause");
46 __asm__ __volatile__("" ::: "memory");
47#endif
48}
49
50SANITIZER_IGNORE_ATOMIC_ALIGNMENT_BEGIN
51template <typename T>
52inline typename T::Type atomic_load(const volatile T *a, memory_order mo) {
53 DCHECK(mo == memory_order_relaxed || mo == memory_order_consume ||
54 mo == memory_order_acquire || mo == memory_order_seq_cst);
55 DCHECK(!((uptr)a % sizeof(*a)));
56 return __atomic_load_n(&a->val_dont_use, mo);
57}
58
59template <typename T>
60inline void atomic_store(volatile T *a, typename T::Type v, memory_order mo) {
61 DCHECK(mo == memory_order_relaxed || mo == memory_order_release ||
62 mo == memory_order_seq_cst);
63 DCHECK(!((uptr)a % sizeof(*a)));
64 __atomic_store_n(&a->val_dont_use, v, mo);
65}
66
67template <typename T>
68inline typename T::Type atomic_fetch_add(volatile T *a, typename T::Type v,
69 memory_order mo) {
70 DCHECK(!((uptr)a % sizeof(*a)));
71 return __atomic_fetch_add(&a->val_dont_use, v, mo);
72}
73
74template <typename T>
75inline typename T::Type atomic_fetch_sub(volatile T *a, typename T::Type v,
76 memory_order mo) {
77 (void)mo;
78 DCHECK(!((uptr)a % sizeof(*a)));
79 return __atomic_fetch_sub(&a->val_dont_use, v, mo);
80}
81
82template <typename T>
83inline typename T::Type atomic_exchange(volatile T *a, typename T::Type v,
84 memory_order mo) {
85 DCHECK(!((uptr)a % sizeof(*a)));
86 return __atomic_exchange_n(&a->val_dont_use, v, mo);
87}
88
89template <typename T>
90inline bool atomic_compare_exchange_strong(volatile T *a, typename T::Type *cmp,
91 typename T::Type xchg,
92 memory_order mo) {
93 // Transitioned from __sync_val_compare_and_swap to support targets like
94 // SPARC V8 that cannot inline atomic cmpxchg. __atomic_compare_exchange
95 // can then be resolved from libatomic. __ATOMIC_SEQ_CST is used to best
96 // match the __sync builtin memory order.
97 return __atomic_compare_exchange(&a->val_dont_use, cmp, &xchg, false,
98 __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
99}
100
101template <typename T>
102inline bool atomic_compare_exchange_weak(volatile T *a, typename T::Type *cmp,
103 typename T::Type xchg,
104 memory_order mo) {
105 return atomic_compare_exchange_strong(a, cmp, xchg, mo);
106}
107
108SANITIZER_IGNORE_ATOMIC_ALIGNMENT_END
109
110} // namespace __sanitizer
111
112#undef ATOMIC_ORDER
113
114#endif // SANITIZER_ATOMIC_CLANG_H