Siva Annamalai
68 lines
2.2 KiB
C++
68 lines
2.2 KiB
C++
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_ATOMIC_H_
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#define VM_ATOMIC_H_
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#include "platform/globals.h"
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#include "vm/allocation.h"
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#include "vm/simulator.h"
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namespace dart {
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class AtomicOperations : public AllStatic {
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public:
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// Atomically fetch the value at p and increment the value at p.
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// Returns the original value at p.
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//
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// NOTE: Not to be used for any atomic operations involving memory locations
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// that are accessed by generated code.
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static uintptr_t FetchAndIncrement(uintptr_t* p);
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static uintptr_t FetchAndIncrementBy(intptr_t* p, intptr_t value);
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// Atomically fetch the value at p and decrement the value at p.
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// Returns the original value at p.
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//
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// NOTE: Not to be used for any atomic operations involving memory locations
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// that are accessed by generated code.
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static uintptr_t FetchAndDecrement(uintptr_t* p);
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static uintptr_t FetchAndDecrementBy(intptr_t* p, intptr_t value);
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// Atomically compare *ptr to old_value, and if equal, store new_value.
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// Returns the original value at ptr.
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//
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// NOTE: OK to use with memory locations that are accessed by generated code
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static uword CompareAndSwapWord(uword* ptr, uword old_value, uword new_value);
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static uint32_t CompareAndSwapUint32(
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uint32_t* ptr, uint32_t old_value, uint32_t new_value);
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// Performs a load of a word from 'ptr', but without any guarantees about
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// memory order (i.e., no load barriers/fences).
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static uword LoadRelaxed(uword* ptr) {
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return *static_cast<volatile uword*>(ptr);
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}
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};
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} // namespace dart
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// We need to use the simulator to ensure that atomic operations are observed
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// both in C++ and in generated code if the simulator is active.
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#include "vm/atomic_simulator.h"
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#if defined(TARGET_OS_ANDROID)
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#include "vm/atomic_android.h"
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#elif defined(TARGET_OS_LINUX)
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#include "vm/atomic_linux.h"
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#elif defined(TARGET_OS_MACOS)
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#include "vm/atomic_macos.h"
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#elif defined(TARGET_OS_WINDOWS)
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#include "vm/atomic_win.h"
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#else
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#error Unknown target os.
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#endif
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#endif // VM_ATOMIC_H_
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