2 * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
3 * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
15 * its contributors may be used to endorse or promote products derived
16 * from this software without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based
31 * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license
32 * is virtually identical to the Apple license above but is included here for completeness.
34 * Boost Software License - Version 1.0 - August 17th, 2003
36 * Permission is hereby granted, free of charge, to any person or organization
37 * obtaining a copy of the software and accompanying documentation covered by
38 * this license (the "Software") to use, reproduce, display, distribute,
39 * execute, and transmit the Software, and to prepare derivative works of the
40 * Software, and to permit third-parties to whom the Software is furnished to
41 * do so, all subject to the following:
43 * The copyright notices in the Software and this entire statement, including
44 * the above license grant, this restriction and the following disclaimer,
45 * must be included in all copies of the Software, in whole or in part, and
46 * all derivative works of the Software, unless such copies or derivative
47 * works are solely in the form of machine-executable object code generated by
48 * a source language processor.
50 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
51 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
52 * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
53 * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
54 * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
55 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
56 * DEALINGS IN THE SOFTWARE.
62 #include <wtf/Platform.h>
63 #include <wtf/StdLibExtras.h>
64 #include <wtf/UnusedParam.h>
69 #include <libkern/OSAtomic.h>
73 #include <sys/atomics.h>
75 #if (__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2))
76 #include <ext/atomicity.h>
78 #include <bits/atomicity.h>
85 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
87 #if COMPILER(MINGW) || COMPILER(MSVC7_OR_LOWER) || OS(WINCE)
88 inline int atomicIncrement(int* addend) { return InterlockedIncrement(reinterpret_cast<long*>(addend)); }
89 inline int atomicDecrement(int* addend) { return InterlockedDecrement(reinterpret_cast<long*>(addend)); }
91 inline int atomicIncrement(int volatile* addend) { return InterlockedIncrement(reinterpret_cast<long volatile*>(addend)); }
92 inline int atomicDecrement(int volatile* addend) { return InterlockedDecrement(reinterpret_cast<long volatile*>(addend)); }
96 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
98 inline int atomicIncrement(int volatile* addend) { return OSAtomicIncrement32Barrier(const_cast<int*>(addend)); }
99 inline int atomicDecrement(int volatile* addend) { return OSAtomicDecrement32Barrier(const_cast<int*>(addend)); }
102 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
104 // Note, atomic_{add, sub}_value() return the previous value of addend's content.
105 inline int atomicIncrement(int volatile* addend) { return static_cast<int>(atomic_add_value(reinterpret_cast<unsigned volatile*>(addend), 1)) + 1; }
106 inline int atomicDecrement(int volatile* addend) { return static_cast<int>(atomic_sub_value(reinterpret_cast<unsigned volatile*>(addend), 1)) - 1; }
109 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
111 inline int atomicIncrement(int volatile* addend) { return __atomic_inc(addend); }
112 inline int atomicDecrement(int volatile* addend) { return __atomic_dec(addend); }
114 #elif COMPILER(GCC) && !CPU(SPARC64) // sizeof(_Atomic_word) != sizeof(int) on sparc64 gcc
115 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
117 inline int atomicIncrement(int volatile* addend) { return __gnu_cxx::__exchange_and_add(addend, 1) + 1; }
118 inline int atomicDecrement(int volatile* addend) { return __gnu_cxx::__exchange_and_add(addend, -1) - 1; }
123 inline bool weakCompareAndSwap(volatile unsigned* location, unsigned expected, unsigned newValue)
126 return InterlockedCompareExchange(reinterpret_cast<LONG*>(const_cast<unsigned*>(location)), static_cast<LONG>(newValue), static_cast<LONG>(expected)) == static_cast<LONG>(expected);
128 return InterlockedCompareExchange(reinterpret_cast<LONG volatile*>(location), static_cast<LONG>(newValue), static_cast<LONG>(expected)) == static_cast<LONG>(expected);
132 inline bool weakCompareAndSwap(void*volatile* location, void* expected, void* newValue)
134 return InterlockedCompareExchangePointer(location, newValue, expected) == expected;
136 #else // OS(WINDOWS) --> not windows
137 #if COMPILER(GCC) && !COMPILER(CLANG) // Work around a gcc bug
138 inline bool weakCompareAndSwap(volatile unsigned* location, unsigned expected, unsigned newValue)
140 inline bool weakCompareAndSwap(unsigned* location, unsigned expected, unsigned newValue)
143 #if ENABLE(COMPARE_AND_SWAP)
145 #if CPU(X86) || CPU(X86_64)
147 "lock; cmpxchgl %3, %2\n\t"
149 : "+a"(expected), "=q"(result), "+m"(*location)
153 #elif CPU(ARM_THUMB2)
160 "strex %1, %4, %0\n\t"
162 : "+m"(*location), "=&r"(result), "=&r"(tmp)
163 : "r"(expected), "r"(newValue)
167 #error "Bad architecture for compare and swap."
171 UNUSED_PARAM(location);
172 UNUSED_PARAM(expected);
173 UNUSED_PARAM(newValue);
179 inline bool weakCompareAndSwap(void*volatile* location, void* expected, void* newValue)
181 #if ENABLE(COMPARE_AND_SWAP)
185 "lock; cmpxchgq %3, %2\n\t"
187 : "+a"(expected), "=q"(result), "+m"(*location)
193 return weakCompareAndSwap(bitwise_cast<unsigned*>(location), bitwise_cast<unsigned>(expected), bitwise_cast<unsigned>(newValue));
195 #else // ENABLE(COMPARE_AND_SWAP)
196 UNUSED_PARAM(location);
197 UNUSED_PARAM(expected);
198 UNUSED_PARAM(newValue);
201 #endif // ENABLE(COMPARE_AND_SWAP)
203 #endif // OS(WINDOWS) (end of the not-windows case)
205 inline bool weakCompareAndSwapUIntPtr(volatile uintptr_t* location, uintptr_t expected, uintptr_t newValue)
207 return weakCompareAndSwap(reinterpret_cast<void*volatile*>(location), reinterpret_cast<void*>(expected), reinterpret_cast<void*>(newValue));
212 inline void memoryBarrierAfterLock()
214 asm volatile("dmb" ::: "memory");
217 inline void memoryBarrierBeforeUnlock()
219 asm volatile("dmb" ::: "memory");
224 inline void memoryBarrierAfterLock() { }
225 inline void memoryBarrierBeforeUnlock() { }
231 #if USE(LOCKFREE_THREADSAFEREFCOUNTED)
232 using WTF::atomicDecrement;
233 using WTF::atomicIncrement;