compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h

   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 #if defined(__i386__) || defined(__x86_64__)
  18 # include "sanitizer_atomic_clang_x86.h"
  19 #else
  20 # include "sanitizer_atomic_clang_other.h"
  21 #endif
  22
  23 namespace __sanitizer {
  24
  25 // We would like to just use compiler builtin atomic operations
  26 // for loads and stores, but they are mostly broken in clang:
  27 // - they lead to vastly inefficient code generation
  28 // (http://llvm.org/bugs/show_bug.cgi?id=17281)
  29 // - 64-bit atomic operations are not implemented on x86_32
  30 // (http://llvm.org/bugs/show_bug.cgi?id=15034)
  31 // - they are not implemented on ARM
  32 // error: undefined reference to '__atomic_load_4'
  33
  34 // See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
  35 // for mappings of the memory model to different processors.
  36
  37 inline void atomic_signal_fence(memory_order) {
  38   __asm__ __volatile__("" ::: "memory");
  39 }
  40
  41 inline void atomic_thread_fence(memory_order) {
  42   __sync_synchronize();
  43 }
  44
  45 template<typename T>
  46 inline typename T::Type atomic_fetch_add(volatile T *a,
  47     typename T::Type v, memory_order mo) {
  48   (void)mo;
  49   DCHECK(!((uptr)a % sizeof(*a)));
  50   return __sync_fetch_and_add(&a->val_dont_use, v);
  51 }
  52
  53 template<typename T>
  54 inline typename T::Type atomic_fetch_sub(volatile T *a,
  55     typename T::Type v, memory_order mo) {
  56   (void)mo;
  57   DCHECK(!((uptr)a % sizeof(*a)));
  58   return __sync_fetch_and_add(&a->val_dont_use, -v);
  59 }
  60
  61 template<typename T>
  62 inline typename T::Type atomic_exchange(volatile T *a,
  63     typename T::Type v, memory_order mo) {
  64   DCHECK(!((uptr)a % sizeof(*a)));
  65   if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst))
  66     __sync_synchronize();
  67   v = __sync_lock_test_and_set(&a->val_dont_use, v);
  68   if (mo == memory_order_seq_cst)
  69     __sync_synchronize();
  70   return v;
  71 }
  72
  73 template <typename T>
  74 inline bool atomic_compare_exchange_strong(volatile T *a, typename T::Type *cmp,
  75                                            typename T::Type xchg,
  76                                            memory_order mo) {
  77   // Transitioned from __sync_val_compare_and_swap to support targets like
  78   // SPARC V8 that cannot inline atomic cmpxchg.  __atomic_compare_exchange
  79   // can then be resolved from libatomic.  __ATOMIC_SEQ_CST is used to best
  80   // match the __sync builtin memory order.
  81   return __atomic_compare_exchange(&a->val_dont_use, cmp, &xchg, false,
  82                                    __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
  83 }
  84
  85 template<typename T>
  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) && _MIPS_SIM == _ABIO32
  99 #  include "sanitizer_atomic_clang_mips.h"
 100 #endif
 101
 102 #undef ATOMIC_ORDER
 103
 104 #endif  // SANITIZER_ATOMIC_CLANG_H