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