60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
//===-- Atomic.cpp - Atomic Operations --------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements atomic operations.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/Atomic.h"
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#include "llvm/Config/llvm-config.h"
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using namespace llvm;
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#if defined(_MSC_VER)
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#include <intrin.h>
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// We must include windows.h after intrin.h.
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#include <windows.h>
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#undef MemoryFence
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#endif
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#if defined(__GNUC__) || (defined(__IBMCPP__) && __IBMCPP__ >= 1210)
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#define GNU_ATOMICS
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#endif
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void sys::MemoryFence() {
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#if LLVM_HAS_ATOMICS == 0
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return;
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#else
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# if defined(GNU_ATOMICS)
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__sync_synchronize();
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# elif defined(_MSC_VER)
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MemoryBarrier();
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# else
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# error No memory fence implementation for your platform!
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# endif
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#endif
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}
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sys::cas_flag sys::CompareAndSwap(volatile sys::cas_flag* ptr,
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sys::cas_flag new_value,
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sys::cas_flag old_value) {
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#if LLVM_HAS_ATOMICS == 0
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sys::cas_flag result = *ptr;
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if (result == old_value)
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*ptr = new_value;
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return result;
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#elif defined(GNU_ATOMICS)
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return __sync_val_compare_and_swap(ptr, old_value, new_value);
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#elif defined(_MSC_VER)
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return InterlockedCompareExchange(ptr, new_value, old_value);
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#else
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# error No compare-and-swap implementation for your platform!
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#endif
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}
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