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Diffstat (limited to 'src/google/protobuf/stubs/atomicops.h')
| -rw-r--r-- | src/google/protobuf/stubs/atomicops.h | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/google/protobuf/stubs/atomicops.h b/src/google/protobuf/stubs/atomicops.h new file mode 100644 index 0000000..76c026c --- /dev/null +++ b/src/google/protobuf/stubs/atomicops.h @@ -0,0 +1,216 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2012 Google Inc. All rights reserved. +// http://code.google.com/p/protobuf/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * 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. +// * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT +// OWNER OR 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. + +// The routines exported by this module are subtle. If you use them, even if +// you get the code right, it will depend on careful reasoning about atomicity +// and memory ordering; it will be less readable, and harder to maintain. If +// you plan to use these routines, you should have a good reason, such as solid +// evidence that performance would otherwise suffer, or there being no +// alternative. You should assume only properties explicitly guaranteed by the +// specifications in this file. You are almost certainly _not_ writing code +// just for the x86; if you assume x86 semantics, x86 hardware bugs and +// implementations on other archtectures will cause your code to break. If you +// do not know what you are doing, avoid these routines, and use a Mutex. +// +// It is incorrect to make direct assignments to/from an atomic variable. +// You should use one of the Load or Store routines. The NoBarrier +// versions are provided when no barriers are needed: +// NoBarrier_Store() +// NoBarrier_Load() +// Although there are currently no compiler enforcement, you are encouraged +// to use these. + +// This header and the implementations for each platform (located in +// atomicops_internals_*) must be kept in sync with the upstream code (V8). + +#ifndef GOOGLE_PROTOBUF_ATOMICOPS_H_ +#define GOOGLE_PROTOBUF_ATOMICOPS_H_ + +// Don't include this file for people not concerned about thread safety. +#ifndef GOOGLE_PROTOBUF_NO_THREAD_SAFETY + +#include <google/protobuf/stubs/platform_macros.h> + +namespace google { +namespace protobuf { +namespace internal { + +typedef int32 Atomic32; +#ifdef GOOGLE_PROTOBUF_ARCH_64_BIT +// We need to be able to go between Atomic64 and AtomicWord implicitly. This +// means Atomic64 and AtomicWord should be the same type on 64-bit. +#if defined(__ILP32__) || defined(GOOGLE_PROTOBUF_OS_NACL) +// NaCl's intptr_t is not actually 64-bits on 64-bit! +// http://code.google.com/p/nativeclient/issues/detail?id=1162 +typedef int64 Atomic64; +#else +typedef intptr_t Atomic64; +#endif +#endif + +// Use AtomicWord for a machine-sized pointer. It will use the Atomic32 or +// Atomic64 routines below, depending on your architecture. +typedef intptr_t AtomicWord; + +// Atomically execute: +// result = *ptr; +// if (*ptr == old_value) +// *ptr = new_value; +// return result; +// +// I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value". +// Always return the old value of "*ptr" +// +// This routine implies no memory barriers. +Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value); + +// Atomically store new_value into *ptr, returning the previous value held in +// *ptr. This routine implies no memory barriers. +Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value); + +// Atomically increment *ptr by "increment". Returns the new value of +// *ptr with the increment applied. This routine implies no memory barriers. +Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr, Atomic32 increment); + +Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr, + Atomic32 increment); + +// These following lower-level operations are typically useful only to people +// implementing higher-level synchronization operations like spinlocks, +// mutexes, and condition-variables. They combine CompareAndSwap(), a load, or +// a store with appropriate memory-ordering instructions. "Acquire" operations +// ensure that no later memory access can be reordered ahead of the operation. +// "Release" operations ensure that no previous memory access can be reordered +// after the operation. "Barrier" operations have both "Acquire" and "Release" +// semantics. A MemoryBarrier() has "Barrier" semantics, but does no memory +// access. +Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value); +Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr, + Atomic32 old_value, + Atomic32 new_value); + +#if defined(__MINGW32__) && defined(MemoryBarrier) +#undef MemoryBarrier +#endif +void MemoryBarrier(); +void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value); +void Acquire_Store(volatile Atomic32* ptr, Atomic32 value); +void Release_Store(volatile Atomic32* ptr, Atomic32 value); + +Atomic32 NoBarrier_Load(volatile const Atomic32* ptr); +Atomic32 Acquire_Load(volatile const Atomic32* ptr); +Atomic32 Release_Load(volatile const Atomic32* ptr); + +// 64-bit atomic operations (only available on 64-bit processors). +#ifdef GOOGLE_PROTOBUF_ARCH_64_BIT +Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr, + Atomic64 old_value, + Atomic64 new_value); +Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value); +Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment); +Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr, Atomic64 increment); + +Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr, + Atomic64 old_value, + Atomic64 new_value); +Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr, + Atomic64 old_value, + Atomic64 new_value); +void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value); +void Acquire_Store(volatile Atomic64* ptr, Atomic64 value); +void Release_Store(volatile Atomic64* ptr, Atomic64 value); +Atomic64 NoBarrier_Load(volatile const Atomic64* ptr); +Atomic64 Acquire_Load(volatile const Atomic64* ptr); +Atomic64 Release_Load(volatile const Atomic64* ptr); +#endif // GOOGLE_PROTOBUF_ARCH_64_BIT + +} // namespace internal +} // namespace protobuf +} // namespace google + +// Include our platform specific implementation. +#define GOOGLE_PROTOBUF_ATOMICOPS_ERROR \ +#error "Atomic operations are not supported on your platform" + +// ThreadSanitizer, http://clang.llvm.org/docs/ThreadSanitizer.html. +#if defined(THREAD_SANITIZER) +#include <google/protobuf/stubs/atomicops_internals_tsan.h> +// MSVC. +#elif defined(_MSC_VER) +#if defined(GOOGLE_PROTOBUF_ARCH_IA32) || defined(GOOGLE_PROTOBUF_ARCH_X64) +#include <google/protobuf/stubs/atomicops_internals_x86_msvc.h> +#else +GOOGLE_PROTOBUF_ATOMICOPS_ERROR +#endif + +// Apple. +#elif defined(GOOGLE_PROTOBUF_OS_APPLE) +#include <google/protobuf/stubs/atomicops_internals_macosx.h> + +// GCC. +#elif defined(__GNUC__) +#if defined(GOOGLE_PROTOBUF_ARCH_IA32) || defined(GOOGLE_PROTOBUF_ARCH_X64) +#include <google/protobuf/stubs/atomicops_internals_x86_gcc.h> +#elif defined(GOOGLE_PROTOBUF_ARCH_ARM) && defined(__linux__) +#include <google/protobuf/stubs/atomicops_internals_arm_gcc.h> +#elif defined(GOOGLE_PROTOBUF_ARCH_AARCH64) +#include <google/protobuf/stubs/atomicops_internals_arm64_gcc.h> +#elif defined(GOOGLE_PROTOBUF_ARCH_ARM_QNX) +#include <google/protobuf/stubs/atomicops_internals_arm_qnx.h> +#elif defined(GOOGLE_PROTOBUF_ARCH_MIPS) || defined(GOOGLE_PROTOBUF_ARCH_MIPS64) +#include <google/protobuf/stubs/atomicops_internals_mips_gcc.h> +#elif defined(__native_client__) +#include <google/protobuf/stubs/atomicops_internals_pnacl.h> +#elif (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)) +#include <google/protobuf/stubs/atomicops_internals_generic_gcc.h> +#else +GOOGLE_PROTOBUF_ATOMICOPS_ERROR +#endif + +// Unknown. +#else +GOOGLE_PROTOBUF_ATOMICOPS_ERROR +#endif + +// On some platforms we need additional declarations to make AtomicWord +// compatible with our other Atomic* types. +#if defined(GOOGLE_PROTOBUF_OS_APPLE) +#include <google/protobuf/stubs/atomicops_internals_atomicword_compat.h> +#endif + +#undef GOOGLE_PROTOBUF_ATOMICOPS_ERROR + +#endif // GOOGLE_PROTOBUF_NO_THREAD_SAFETY + +#endif // GOOGLE_PROTOBUF_ATOMICOPS_H_ |