1//===-- sanitizer_atomic_clang_other.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_OTHER_H
15#define SANITIZER_ATOMIC_CLANG_OTHER_H
16
17namespace __sanitizer {
18
19
20inline void proc_yield(int cnt) {
21  __asm__ __volatile__("" ::: "memory");
22}
23
24template<typename T>
25inline typename T::Type atomic_load(
26    const volatile T *a, memory_order mo) {
27  DCHECK(mo & (memory_order_relaxed | memory_order_consume
28      | memory_order_acquire | memory_order_seq_cst));
29  DCHECK(!((uptr)a % sizeof(*a)));
30  typename T::Type v;
31
32  if (sizeof(*a) < 8 || sizeof(void*) == 8) {
33    // Assume that aligned loads are atomic.
34    if (mo == memory_order_relaxed) {
35      v = a->val_dont_use;
36    } else if (mo == memory_order_consume) {
37      // Assume that processor respects data dependencies
38      // (and that compiler won't break them).
39      __asm__ __volatile__("" ::: "memory");
40      v = a->val_dont_use;
41      __asm__ __volatile__("" ::: "memory");
42    } else if (mo == memory_order_acquire) {
43      __asm__ __volatile__("" ::: "memory");
44      v = a->val_dont_use;
45      __sync_synchronize();
46    } else {  // seq_cst
47      // E.g. on POWER we need a hw fence even before the store.
48      __sync_synchronize();
49      v = a->val_dont_use;
50      __sync_synchronize();
51    }
52  } else {
53    __atomic_load(const_cast<typename T::Type volatile *>(&a->val_dont_use), &v,
54                  __ATOMIC_SEQ_CST);
55  }
56  return v;
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 | memory_order_release
62      | memory_order_seq_cst));
63  DCHECK(!((uptr)a % sizeof(*a)));
64
65  if (sizeof(*a) < 8 || sizeof(void*) == 8) {
66    // Assume that aligned loads are atomic.
67    if (mo == memory_order_relaxed) {
68      a->val_dont_use = v;
69    } else if (mo == memory_order_release) {
70      __sync_synchronize();
71      a->val_dont_use = v;
72      __asm__ __volatile__("" ::: "memory");
73    } else {  // seq_cst
74      __sync_synchronize();
75      a->val_dont_use = v;
76      __sync_synchronize();
77    }
78  } else {
79    __atomic_store(&a->val_dont_use, &v, __ATOMIC_SEQ_CST);
80  }
81}
82
83}  // namespace __sanitizer
84
85#endif  // #ifndef SANITIZER_ATOMIC_CLANG_OTHER_H
86