sanitizer_atomic_clang.h revision 2d1fdb26e458c4ddc04155c1d421bced3ba90cd0 
1//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
11// Not intended for direct inclusion. Include sanitizer_atomic.h.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef SANITIZER_ATOMIC_CLANG_H
16#define SANITIZER_ATOMIC_CLANG_H
17
18#if defined(__i386__) || defined(__x86_64__)
19# include "sanitizer_atomic_clang_x86.h"
20#else
21# include "sanitizer_atomic_clang_other.h"
22#endif
23
24namespace __sanitizer {
25
26// We would like to just use compiler builtin atomic operations
27// for loads and stores, but they are mostly broken in clang:
28// - they lead to vastly inefficient code generation
29// (http://llvm.org/bugs/show_bug.cgi?id=17281)
30// - 64-bit atomic operations are not implemented on x86_32
31// (http://llvm.org/bugs/show_bug.cgi?id=15034)
32// - they are not implemented on ARM
33// error: undefined reference to '__atomic_load_4'
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) {
39  __asm__ __volatile__("" ::: "memory");
40}
41
42INLINE void atomic_thread_fence(memory_order) {
43  __sync_synchronize();
44}
45
46template<typename T>
47INLINE typename T::Type atomic_fetch_add(volatile T *a,
48    typename T::Type v, memory_order mo) {
49  (void)mo;
50  DCHECK(!((uptr)a % sizeof(*a)));
51  return __sync_fetch_and_add(&a->val_dont_use, v);
52}
53
54template<typename T>
55INLINE typename T::Type atomic_fetch_sub(volatile T *a,
56    typename T::Type v, memory_order mo) {
57  (void)mo;
58  DCHECK(!((uptr)a % sizeof(*a)));
59  return __sync_fetch_and_add(&a->val_dont_use, -v);
60}
61
62template<typename T>
63INLINE typename T::Type atomic_exchange(volatile T *a,
64    typename T::Type v, memory_order mo) {
65  DCHECK(!((uptr)a % sizeof(*a)));
66  if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst))
67    __sync_synchronize();
68  v = __sync_lock_test_and_set(&a->val_dont_use, v);
69  if (mo == memory_order_seq_cst)
70    __sync_synchronize();
71  return v;
72}
73
74template<typename T>
75INLINE bool atomic_compare_exchange_strong(volatile T *a,
76                                           typename T::Type *cmp,
77                                           typename T::Type xchg,
78                                           memory_order mo) {
79  typedef typename T::Type Type;
80  Type cmpv = *cmp;
81  Type prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg);
82  if (prev == cmpv)
83    return true;
84  *cmp = prev;
85  return false;
86}
87
88template<typename T>
89INLINE bool atomic_compare_exchange_weak(volatile T *a,
90                                         typename T::Type *cmp,
91                                         typename T::Type xchg,
92                                         memory_order mo) {
93  return atomic_compare_exchange_strong(a, cmp, xchg, mo);
94}
95
96}  // namespace __sanitizer
97
98#undef ATOMIC_ORDER
99
100#endif  // SANITIZER_ATOMIC_CLANG_H
101