Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/Atomics.cpp

-/*
- * Copyright (C) 2007, 2008, 2010, 2012 Apple Inc. All rights reserved.
- * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1.  Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer. 
- * 2.  Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in the
- *     documentation and/or other materials provided with the distribution. 
- * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
- *     its contributors may be used to endorse or promote products derived
- *     from this software without specific prior written permission. 
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- *
- * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based
- * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license
- * is virtually identical to the Apple license above but is included here for completeness.
- *
- * Boost Software License - Version 1.0 - August 17th, 2003
- * 
- * Permission is hereby granted, free of charge, to any person or organization
- * obtaining a copy of the software and accompanying documentation covered by
- * this license (the "Software") to use, reproduce, display, distribute,
- * execute, and transmit the Software, and to prepare derivative works of the
- * Software, and to permit third-parties to whom the Software is furnished to
- * do so, all subject to the following:
- * 
- * The copyright notices in the Software and this entire statement, including
- * the above license grant, this restriction and the following disclaimer,
- * must be included in all copies of the Software, in whole or in part, and
- * all derivative works of the Software, unless such copies or derivative
- * works are solely in the form of machine-executable object code generated by
- * a source language processor.
- * 
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
- * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
- * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
- * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- * DEALINGS IN THE SOFTWARE.
- */
-
-#include "config.h"
-#include "Atomics.h"
-
-// Some architectures, like MIPS32, don't have GCC implementation for builtin __sync_* functions
-// with 64 bits variable size. Official GCC answer for the problem: If a target doesn't support
-// atomic operations on certain variable sizes, you are out of luck with atomicity in that case
-// (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56296). GCC >= 4.8 will support __atomic_* builtin
-// functions for this purpose for all the GCC targets, but for current compilers we have to include
-// our own implementation.
-#if COMPILER(GCC) && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8) && USE(LOCKFREE_THREADSAFEREFCOUNTED) && USE(PTHREADS)
-
-#include "ThreadingPrimitives.h"
-
-namespace WTF {
-
-static const size_t kSwapLockCount = 32;
-static Mutex s_swapLocks[kSwapLockCount];
-
-static inline Mutex& getSwapLock(const volatile int64_t* addr)
-{
-    return s_swapLocks[(reinterpret_cast<intptr_t>(addr) >> 3U) % kSwapLockCount];
-}
-
-static int64_t atomicStep(int64_t volatile* addend, int64_t step)
-{
-    Mutex& mutex = getSwapLock(addend);
-
-    mutex.lock();
-    int64_t value = *addend + step;
-    *addend = value;
-    mutex.unlock();
-
-    return value;
-}
-
-extern "C" {
-
-int64_t __sync_add_and_fetch_8(int64_t volatile* addend, int64_t value)
-{
-    return atomicStep(addend, value);
-}
-
-int64_t __sync_sub_and_fetch_8(int64_t volatile* addend, int64_t value)
-{
-    return atomicStep(addend, -value);
-}
-
-} // extern "C"
-
-} // namespace WTF
-
-#endif