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//===- llvm/System/Atomic.h - Atomic Operations -----------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the llvm::sys atomic operations.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SYSTEM_ATOMIC_H
#define LLVM_SYSTEM_ATOMIC_H
#include <stdint.h>
#if defined(__APPLE__)
#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ == 0)
#include <libkern/OSAtomic.h>
#endif
#elif LLVM_ON_WIN32
#include <windows.h>
#endif
namespace llvm {
namespace sys {
#if !defined(ENABLE_THREADS) || ENABLE_THREADS == 0
inline void MemoryFence() {
return;
}
typedef uint32_t cas_flag;
inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
cas_flag result = *dest;
if (result == c)
*dest = exc;
return result;
}
#elif __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
inline void MemoryFence() {
__sync_synchronize();
}
typedef volatile uint32_t cas_flag;
inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
return __sync_val_compare_and_swap(dest, exc, c);
}
#elif defined(__APPLE__)
inline void MemoryFence() {
OSMemoryBarrier();
}
typedef volatile int32_t cas_flag;
inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
cas_flag old = *dest;
OSAtomicCompareAndSwap32(c, exc, dest);
return old;
}
#elif defined(LLVM_ON_WIN32)
inline void MemoryFence() {
#ifdef _MSC_VER
MemoryBarrier();
#elif 0
// FIXME: Requires SSE2 support
__asm__ __volatile__("mfence":::"memory");
#else
// FIXME: just temporary workaround. We need to emit some fence...
__asm__ __volatile__("":::"memory");
#endif
}
typedef volatile long cas_flag;
inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
return InterlockedCompareExchange(dest, exc, c);
}
#else
#error No memory atomics implementation for your platform!
#endif
}
}
#endif
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