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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
#if defined(_MSC_VER)
#include <windows.h>
#endif
namespace llvm {
namespace sys {
inline void MemoryFence() {
#if LLVM_MULTITHREADED==0
return;
#else
# if defined(__GNUC__)
__sync_synchronize();
# elif defined(_MSC_VER)
MemoryBarrier();
# else
# error No memory fence implementation for your platform!
# endif
#endif
}
#if LLVM_MULTITHREADED==0
typedef unsigned long cas_flag;
template<typename T>
inline T CompareAndSwap(volatile T* dest,
T exc, T c) {
T result = *dest;
if (result == c)
*dest = exc;
return result;
}
#elif defined(__GNUC__)
typedef unsigned long cas_flag;
template<typename T>
inline T CompareAndSwap(volatile T* ptr,
T new_value,
T old_value) {
return __sync_val_compare_and_swap(ptr, old_value, new_value);
}
#elif defined(_MSC_VER)
typedef LONG cas_flag;
template<typename T>
inline T CompareAndSwap(volatile T* ptr,
T new_value,
T old_value) {
if (sizeof(T) == 4)
return InterlockedCompareExchange(ptr, new_value, old_value);
else if (sizeof(T) == 8)
return InterlockedCompareExchange64(ptr, new_value, old_value);
else
assert(0 && "Unsupported compare-and-swap size!");
}
template<typename T>
inline T* CompareAndSwap<T*>(volatile T** ptr,
T* new_value,
T* old_value) {
return InterlockedCompareExchangePtr(ptr, new_value, old_value);
}
#else
# error No compare-and-swap implementation for your platform!
#endif
}
}
#endif
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