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//===-- sanitizer_atomic_clang.h --------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
// Not intended for direct inclusion. Include sanitizer_atomic.h.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_ATOMIC_CLANG_H
#define SANITIZER_ATOMIC_CLANG_H
#if defined(__i386__) || defined(__x86_64__)
# include "sanitizer_atomic_clang_x86.h"
#else
# include "sanitizer_atomic_clang_other.h"
#endif
namespace __sanitizer {
// We would like to just use compiler builtin atomic operations
// for loads and stores, but they are mostly broken in clang:
// - they lead to vastly inefficient code generation
// (http://llvm.org/bugs/show_bug.cgi?id=17281)
// - 64-bit atomic operations are not implemented on x86_32
// (http://llvm.org/bugs/show_bug.cgi?id=15034)
// - they are not implemented on ARM
// error: undefined reference to '__atomic_load_4'
// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
// for mappings of the memory model to different processors.
inline void atomic_signal_fence(memory_order) {
__asm__ __volatile__("" ::: "memory");
}
inline void atomic_thread_fence(memory_order) {
__sync_synchronize();
}
template<typename T>
inline typename T::Type atomic_fetch_add(volatile T *a,
typename T::Type v, memory_order mo) {
(void)mo;
DCHECK(!((uptr)a % sizeof(*a)));
return __sync_fetch_and_add(&a->val_dont_use, v);
}
template<typename T>
inline typename T::Type atomic_fetch_sub(volatile T *a,
typename T::Type v, memory_order mo) {
(void)mo;
DCHECK(!((uptr)a % sizeof(*a)));
return __sync_fetch_and_add(&a->val_dont_use, -v);
}
template<typename T>
inline typename T::Type atomic_exchange(volatile T *a,
typename T::Type v, memory_order mo) {
DCHECK(!((uptr)a % sizeof(*a)));
if (mo & (memory_order_release | memory_order_acq_rel | memory_order_seq_cst))
__sync_synchronize();
v = __sync_lock_test_and_set(&a->val_dont_use, v);
if (mo == memory_order_seq_cst)
__sync_synchronize();
return v;
}
template <typename T>
inline bool atomic_compare_exchange_strong(volatile T *a, typename T::Type *cmp,
typename T::Type xchg,
memory_order mo) {
// Transitioned from __sync_val_compare_and_swap to support targets like
// SPARC V8 that cannot inline atomic cmpxchg. __atomic_compare_exchange
// can then be resolved from libatomic. __ATOMIC_SEQ_CST is used to best
// match the __sync builtin memory order.
return __atomic_compare_exchange(&a->val_dont_use, cmp, &xchg, false,
__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
}
template<typename T>
inline bool atomic_compare_exchange_weak(volatile T *a,
typename T::Type *cmp,
typename T::Type xchg,
memory_order mo) {
return atomic_compare_exchange_strong(a, cmp, xchg, mo);
}
} // namespace __sanitizer
// This include provides explicit template instantiations for atomic_uint64_t
// on MIPS32, which does not directly support 8 byte atomics. It has to
// proceed the template definitions above.
#if defined(_MIPS_SIM) && defined(_ABIO32) && _MIPS_SIM == _ABIO32
# include "sanitizer_atomic_clang_mips.h"
#endif
#undef ATOMIC_ORDER
#endif // SANITIZER_ATOMIC_CLANG_H
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