1//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===//
2//
3// This file is distributed under the University of Illinois Open Source
4// License. See LICENSE.TXT for details.
5//
6//===----------------------------------------------------------------------===//
7//
8// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
9// Not intended for direct inclusion. Include sanitizer_atomic.h.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef SANITIZER_ATOMIC_CLANG_H
14#define SANITIZER_ATOMIC_CLANG_H
15
16#if defined(__i386__) || defined(__x86_64__)
17# include "sanitizer_atomic_clang_x86.h"
18#else
19# include "sanitizer_atomic_clang_other.h"
20#endif
21
22namespace __sanitizer {
23
24// We would like to just use compiler builtin atomic operations
25// for loads and stores, but they are mostly broken in clang:
26// - they lead to vastly inefficient code generation
27// (http://llvm.org/bugs/show_bug.cgi?id=17281)
28// - 64-bit atomic operations are not implemented on x86_32
29// (http://llvm.org/bugs/show_bug.cgi?id=15034)
30// - they are not implemented on ARM
31// error: undefined reference to '__atomic_load_4'
32
33// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
34// for mappings of the memory model to different processors.
35
36INLINE void atomic_signal_fence(memory_order) {
37  __asm__ __volatile__("" ::: "memory");
38}
39
40INLINE void atomic_thread_fence(memory_order) {
41  __sync_synchronize();
42}
43
44template<typename T>
45INLINE typename T::Type atomic_fetch_add(volatile T *a,
46    typename T::Type v, memory_order mo) {
47  (void)mo;
48  DCHECK(!((uptr)a % sizeof(*a)));
49  return __sync_fetch_and_add(&a->val_dont_use, v);
50}
51
52template<typename T>
53INLINE typename T::Type atomic_fetch_sub(volatile T *a,
54    typename T::Type v, memory_order mo) {
55  (void)mo;
56  DCHECK(!((uptr)a % sizeof(*a)));
57  return __sync_fetch_and_add(&a->val_dont_use, -v);
58}
59
60template<typename T>
61INLINE typename T::Type atomic_exchange(volatile T *a,
62    typename T::Type v, memory_order mo) {
63  DCHECK(!((uptr)a % sizeof(*a)));
64  if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst))
65    __sync_synchronize();
66  v = __sync_lock_test_and_set(&a->val_dont_use, v);
67  if (mo == memory_order_seq_cst)
68    __sync_synchronize();
69  return v;
70}
71
72template<typename T>
73INLINE bool atomic_compare_exchange_strong(volatile T *a,
74                                           typename T::Type *cmp,
75                                           typename T::Type xchg,
76                                           memory_order mo) {
77  typedef typename T::Type Type;
78  Type cmpv = *cmp;
79  Type prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg);
80  if (prev == cmpv)
81    return true;
82  *cmp = prev;
83  return false;
84}
85
86template<typename T>
87INLINE bool atomic_compare_exchange_weak(volatile T *a,
88                                         typename T::Type *cmp,
89                                         typename T::Type xchg,
90                                         memory_order mo) {
91  return atomic_compare_exchange_strong(a, cmp, xchg, mo);
92}
93
94}  // namespace __sanitizer
95
96#undef ATOMIC_ORDER
97
98#endif  // SANITIZER_ATOMIC_CLANG_H
99