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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef VM_ATOMIC_H_
#define VM_ATOMIC_H_
#include "platform/globals.h"
#include "vm/allocation.h"
#include "vm/simulator.h"
namespace dart {
class AtomicOperations : public AllStatic {
public:
// Atomically fetch the value at p and increment the value at p.
// Returns the original value at p.
//
// NOTE: Not to be used for any atomic operations involving memory locations
// that are accessed by generated code
static uintptr_t FetchAndIncrement(uintptr_t* p);
// Atomically fetch the value at p and decrement the value at p.
// Returns the original value at p.
//
// NOTE: Not to be used for any atomic operations involving memory locations
// that are accessed by generated code
static uintptr_t FetchAndDecrement(uintptr_t* p);
// Atomically compare *ptr to old_value, and if equal, store new_value.
// Returns the original value at ptr.
//
// NOTE: OK to use with memory locations that are accessed by generated code
static uword CompareAndSwapWord(uword* ptr, uword old_value, uword new_value);
// Performs a load of a word from 'ptr', but without any guarantees about
// memory order (i.e., no load barriers/fences).
static uword LoadRelaxed(uword* ptr) {
return *static_cast<volatile uword*>(ptr);
}
};
} // namespace dart
// We need to use the simulator to ensure that atomic operations are observed
// both in C++ and in generated code if the simulator is active.
#include "vm/atomic_simulator.h"
#if defined(TARGET_OS_ANDROID)
#include "vm/atomic_android.h"
#elif defined(TARGET_OS_LINUX)
#include "vm/atomic_linux.h"
#elif defined(TARGET_OS_MACOS)
#include "vm/atomic_macos.h"
#elif defined(TARGET_OS_WINDOWS)
#include "vm/atomic_win.h"
#else
#error Unknown target os.
#endif
#endif // VM_ATOMIC_H_