Squashed 'third_party/gperftools/' content from commit 54505f1
Change-Id: Id02e833828732b0efe7dac722b8485279e67c5fa
git-subtree-dir: third_party/gperftools
git-subtree-split: 54505f1d50c2d1f4676f5e87090b64a117fd980e
diff --git a/src/base/atomicops.h b/src/base/atomicops.h
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+// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
+/* Copyright (c) 2006, Google Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * ---
+ * Author: Sanjay Ghemawat
+ */
+
+// For atomic operations on statistics counters, see atomic_stats_counter.h.
+// For atomic operations on sequence numbers, see atomic_sequence_num.h.
+// For atomic operations on reference counts, see atomic_refcount.h.
+
+// Some fast atomic operations -- typically with machine-dependent
+// implementations. This file may need editing as Google code is
+// ported to different architectures.
+
+// 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.
+//
+// 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.
+//
+// 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. Moreover, if you choose to use base::subtle::Atomic64 type,
+// you MUST use one of the Load or Store routines to get correct behavior
+// on 32-bit platforms.
+//
+// The intent is eventually to put all of these routines in namespace
+// base::subtle
+
+#ifndef THREAD_ATOMICOPS_H_
+#define THREAD_ATOMICOPS_H_
+
+#include <config.h>
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+
+// ------------------------------------------------------------------------
+// Include the platform specific implementations of the types
+// and operations listed below. Implementations are to provide Atomic32
+// and Atomic64 operations. If there is a mismatch between intptr_t and
+// the Atomic32 or Atomic64 types for a platform, the platform-specific header
+// should define the macro, AtomicWordCastType in a clause similar to the
+// following:
+// #if ...pointers are 64 bits...
+// # define AtomicWordCastType base::subtle::Atomic64
+// #else
+// # define AtomicWordCastType Atomic32
+// #endif
+// TODO(csilvers): figure out ARCH_PIII/ARCH_K8 (perhaps via ./configure?)
+// ------------------------------------------------------------------------
+
+#include "base/arm_instruction_set_select.h"
+#define GCC_VERSION (__GNUC__ * 10000 \
+ + __GNUC_MINOR__ * 100 \
+ + __GNUC_PATCHLEVEL__)
+
+#if defined(TCMALLOC_PREFER_GCC_ATOMICS) && defined(__GNUC__) && GCC_VERSION >= 40700
+#include "base/atomicops-internals-gcc.h"
+#elif defined(__MACH__) && defined(__APPLE__)
+#include "base/atomicops-internals-macosx.h"
+#elif defined(__GNUC__) && defined(ARMV6)
+#include "base/atomicops-internals-arm-v6plus.h"
+#elif defined(ARMV3)
+#include "base/atomicops-internals-arm-generic.h"
+#elif defined(__GNUC__) && (defined(__i386) || defined(__x86_64__))
+#include "base/atomicops-internals-x86.h"
+#elif defined(_WIN32)
+#include "base/atomicops-internals-windows.h"
+#elif defined(__linux__) && defined(__PPC__)
+#include "base/atomicops-internals-linuxppc.h"
+#elif defined(__GNUC__) && defined(__mips__)
+#include "base/atomicops-internals-mips.h"
+#elif defined(__GNUC__) && GCC_VERSION >= 40700
+#include "base/atomicops-internals-gcc.h"
+#else
+#error You need to implement atomic operations for this architecture
+#endif
+
+// Signed type that can hold a pointer and supports the atomic ops below, as
+// well as atomic loads and stores. Instances must be naturally-aligned.
+typedef intptr_t AtomicWord;
+
+#ifdef AtomicWordCastType
+// ------------------------------------------------------------------------
+// This section is needed only when explicit type casting is required to
+// cast AtomicWord to one of the basic atomic types (Atomic64 or Atomic32).
+// It also serves to document the AtomicWord interface.
+// ------------------------------------------------------------------------
+
+namespace base {
+namespace subtle {
+
+// 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.
+inline AtomicWord NoBarrier_CompareAndSwap(volatile AtomicWord* ptr,
+ AtomicWord old_value,
+ AtomicWord new_value) {
+ return NoBarrier_CompareAndSwap(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr),
+ old_value, new_value);
+}
+
+// Atomically store new_value into *ptr, returning the previous value held in
+// *ptr. This routine implies no memory barriers.
+inline AtomicWord NoBarrier_AtomicExchange(volatile AtomicWord* ptr,
+ AtomicWord new_value) {
+ return NoBarrier_AtomicExchange(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), new_value);
+}
+
+inline AtomicWord Acquire_AtomicExchange(volatile AtomicWord* ptr,
+ AtomicWord new_value) {
+ return Acquire_AtomicExchange(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), new_value);
+}
+
+inline AtomicWord Release_AtomicExchange(volatile AtomicWord* ptr,
+ AtomicWord new_value) {
+ return Release_AtomicExchange(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), new_value);
+}
+
+inline AtomicWord Acquire_CompareAndSwap(volatile AtomicWord* ptr,
+ AtomicWord old_value,
+ AtomicWord new_value) {
+ return base::subtle::Acquire_CompareAndSwap(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr),
+ old_value, new_value);
+}
+
+inline AtomicWord Release_CompareAndSwap(volatile AtomicWord* ptr,
+ AtomicWord old_value,
+ AtomicWord new_value) {
+ return base::subtle::Release_CompareAndSwap(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr),
+ old_value, new_value);
+}
+
+inline void NoBarrier_Store(volatile AtomicWord *ptr, AtomicWord value) {
+ NoBarrier_Store(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), value);
+}
+
+inline void Acquire_Store(volatile AtomicWord* ptr, AtomicWord value) {
+ return base::subtle::Acquire_Store(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), value);
+}
+
+inline void Release_Store(volatile AtomicWord* ptr, AtomicWord value) {
+ return base::subtle::Release_Store(
+ reinterpret_cast<volatile AtomicWordCastType*>(ptr), value);
+}
+
+inline AtomicWord NoBarrier_Load(volatile const AtomicWord *ptr) {
+ return NoBarrier_Load(
+ reinterpret_cast<volatile const AtomicWordCastType*>(ptr));
+}
+
+inline AtomicWord Acquire_Load(volatile const AtomicWord* ptr) {
+ return base::subtle::Acquire_Load(
+ reinterpret_cast<volatile const AtomicWordCastType*>(ptr));
+}
+
+inline AtomicWord Release_Load(volatile const AtomicWord* ptr) {
+ return base::subtle::Release_Load(
+ reinterpret_cast<volatile const AtomicWordCastType*>(ptr));
+}
+
+} // namespace base::subtle
+} // namespace base
+#endif // AtomicWordCastType
+
+// ------------------------------------------------------------------------
+// Commented out type definitions and method declarations for documentation
+// of the interface provided by this module.
+// ------------------------------------------------------------------------
+
+#if 0
+
+// Signed 32-bit type that supports the atomic ops below, as well as atomic
+// loads and stores. Instances must be naturally aligned. This type differs
+// from AtomicWord in 64-bit binaries where AtomicWord is 64-bits.
+typedef int32_t Atomic32;
+
+// Corresponding operations on Atomic32
+namespace base {
+namespace subtle {
+
+// Signed 64-bit type that supports the atomic ops below, as well as atomic
+// loads and stores. Instances must be naturally aligned. This type differs
+// from AtomicWord in 32-bit binaries where AtomicWord is 32-bits.
+typedef int64_t Atomic64;
+
+Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value);
+Atomic32 Acquire_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value);
+Atomic32 Release_AtomicExchange(volatile Atomic32* ptr, Atomic32 new_value);
+Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value);
+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);
+
+// Corresponding operations on Atomic64
+Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
+ Atomic64 old_value,
+ Atomic64 new_value);
+Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value);
+Atomic64 Acquire_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value);
+Atomic64 Release_AtomicExchange(volatile Atomic64* ptr, Atomic64 new_value);
+
+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);
+} // namespace base::subtle
+} // namespace base
+
+void MemoryBarrier();
+
+#endif // 0
+
+
+// ------------------------------------------------------------------------
+// The following are to be deprecated when all uses have been changed to
+// use the base::subtle namespace.
+// ------------------------------------------------------------------------
+
+#ifdef AtomicWordCastType
+// AtomicWord versions to be deprecated
+inline AtomicWord Acquire_CompareAndSwap(volatile AtomicWord* ptr,
+ AtomicWord old_value,
+ AtomicWord new_value) {
+ return base::subtle::Acquire_CompareAndSwap(ptr, old_value, new_value);
+}
+
+inline AtomicWord Release_CompareAndSwap(volatile AtomicWord* ptr,
+ AtomicWord old_value,
+ AtomicWord new_value) {
+ return base::subtle::Release_CompareAndSwap(ptr, old_value, new_value);
+}
+
+inline void Acquire_Store(volatile AtomicWord* ptr, AtomicWord value) {
+ return base::subtle::Acquire_Store(ptr, value);
+}
+
+inline void Release_Store(volatile AtomicWord* ptr, AtomicWord value) {
+ return base::subtle::Release_Store(ptr, value);
+}
+
+inline AtomicWord Acquire_Load(volatile const AtomicWord* ptr) {
+ return base::subtle::Acquire_Load(ptr);
+}
+
+inline AtomicWord Release_Load(volatile const AtomicWord* ptr) {
+ return base::subtle::Release_Load(ptr);
+}
+#endif // AtomicWordCastType
+
+// 32-bit Acquire/Release operations to be deprecated.
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ return base::subtle::Acquire_CompareAndSwap(ptr, old_value, new_value);
+}
+inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
+ Atomic32 old_value,
+ Atomic32 new_value) {
+ return base::subtle::Release_CompareAndSwap(ptr, old_value, new_value);
+}
+inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
+ base::subtle::Acquire_Store(ptr, value);
+}
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+ return base::subtle::Release_Store(ptr, value);
+}
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+ return base::subtle::Acquire_Load(ptr);
+}
+inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
+ return base::subtle::Release_Load(ptr);
+}
+
+#ifdef BASE_HAS_ATOMIC64
+
+// 64-bit Acquire/Release operations to be deprecated.
+
+inline base::subtle::Atomic64 Acquire_CompareAndSwap(
+ volatile base::subtle::Atomic64* ptr,
+ base::subtle::Atomic64 old_value, base::subtle::Atomic64 new_value) {
+ return base::subtle::Acquire_CompareAndSwap(ptr, old_value, new_value);
+}
+inline base::subtle::Atomic64 Release_CompareAndSwap(
+ volatile base::subtle::Atomic64* ptr,
+ base::subtle::Atomic64 old_value, base::subtle::Atomic64 new_value) {
+ return base::subtle::Release_CompareAndSwap(ptr, old_value, new_value);
+}
+inline void Acquire_Store(
+ volatile base::subtle::Atomic64* ptr, base::subtle::Atomic64 value) {
+ base::subtle::Acquire_Store(ptr, value);
+}
+inline void Release_Store(
+ volatile base::subtle::Atomic64* ptr, base::subtle::Atomic64 value) {
+ return base::subtle::Release_Store(ptr, value);
+}
+inline base::subtle::Atomic64 Acquire_Load(
+ volatile const base::subtle::Atomic64* ptr) {
+ return base::subtle::Acquire_Load(ptr);
+}
+inline base::subtle::Atomic64 Release_Load(
+ volatile const base::subtle::Atomic64* ptr) {
+ return base::subtle::Release_Load(ptr);
+}
+
+#endif // BASE_HAS_ATOMIC64
+
+#endif // THREAD_ATOMICOPS_H_