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
22 namespace __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
atomic_signal_fence(memory_order)36 INLINE void atomic_signal_fence(memory_order) {
37 __asm__ __volatile__("" ::: "memory");
38 }
39
atomic_thread_fence(memory_order)40 INLINE void atomic_thread_fence(memory_order) {
41 __sync_synchronize();
42 }
43
44 template<typename T>
atomic_fetch_add(volatile T * a,typename T::Type v,memory_order mo)45 INLINE 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
52 template<typename T>
atomic_fetch_sub(volatile T * a,typename T::Type v,memory_order mo)53 INLINE 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
60 template<typename T>
atomic_exchange(volatile T * a,typename T::Type v,memory_order mo)61 INLINE 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
72 template <typename T>
atomic_compare_exchange_strong(volatile T * a,typename T::Type * cmp,typename T::Type xchg,memory_order mo)73 INLINE bool atomic_compare_exchange_strong(volatile T *a, typename T::Type *cmp,
74 typename T::Type xchg,
75 memory_order mo) {
76 typedef typename T::Type Type;
77 Type cmpv = *cmp;
78 Type prev;
79 prev = __sync_val_compare_and_swap(&a->val_dont_use, cmpv, xchg);
80 if (prev == cmpv) return true;
81 *cmp = prev;
82 return false;
83 }
84
85 template<typename T>
atomic_compare_exchange_weak(volatile T * a,typename T::Type * cmp,typename T::Type xchg,memory_order mo)86 INLINE bool atomic_compare_exchange_weak(volatile T *a,
87 typename T::Type *cmp,
88 typename T::Type xchg,
89 memory_order mo) {
90 return atomic_compare_exchange_strong(a, cmp, xchg, mo);
91 }
92
93 } // namespace __sanitizer
94
95 // This include provides explicit template instantiations for atomic_uint64_t
96 // on MIPS32, which does not directly support 8 byte atomics. It has to
97 // proceed the template definitions above.
98 #if defined(_MIPS_SIM) && defined(_ABIO32)
99 #include "sanitizer_atomic_clang_mips.h"
100 #endif
101
102 #undef ATOMIC_ORDER
103
104 #endif // SANITIZER_ATOMIC_CLANG_H
105