+++ /dev/null
-// Copyright (c) 2005, 2006, Google Inc.
-// Copyright (c) 2010, Patrick Gansterer <paroga@paroga.com>
-// 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 <opensource@google.com>
-
-#ifndef TCMALLOC_INTERNAL_SPINLOCK_H__
-#define TCMALLOC_INTERNAL_SPINLOCK_H__
-
-#if (CPU(X86) || CPU(X86_64) || CPU(PPC)) && (COMPILER(GCC) || COMPILER(MSVC))
-
-#include <time.h> /* For nanosleep() */
-
-#if HAVE(STDINT_H)
-#include <stdint.h>
-#elif HAVE(INTTYPES_H)
-#include <inttypes.h>
-#else
-#include <sys/types.h>
-#endif
-
-#if OS(WINDOWS)
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#include <windows.h>
-#else
-#include <sched.h> /* For sched_yield() */
-#endif
-
-static void TCMalloc_SlowLock(volatile unsigned int* lockword);
-
-// The following is a struct so that it can be initialized at compile time
-struct TCMalloc_SpinLock {
-
- inline void Lock() {
- int r;
-#if COMPILER(GCC)
-#if CPU(X86) || CPU(X86_64)
- __asm__ __volatile__
- ("xchgl %0, %1"
- : "=r"(r), "=m"(lockword_)
- : "0"(1), "m"(lockword_)
- : "memory");
-#else
- volatile unsigned int *lockword_ptr = &lockword_;
- __asm__ __volatile__
- ("1: lwarx %0, 0, %1\n\t"
- "stwcx. %2, 0, %1\n\t"
- "bne- 1b\n\t"
- "isync"
- : "=&r" (r), "=r" (lockword_ptr)
- : "r" (1), "1" (lockword_ptr)
- : "memory");
-#endif
-#elif COMPILER(MSVC)
- __asm {
- mov eax, this ; store &lockword_ (which is this+0) in eax
- mov ebx, 1 ; store 1 in ebx
- xchg [eax], ebx ; exchange lockword_ and 1
- mov r, ebx ; store old value of lockword_ in r
- }
-#endif
- if (r) TCMalloc_SlowLock(&lockword_);
- }
-
- inline void Unlock() {
-#if COMPILER(GCC)
-#if CPU(X86) || CPU(X86_64)
- __asm__ __volatile__
- ("movl $0, %0"
- : "=m"(lockword_)
- : "m" (lockword_)
- : "memory");
-#else
- __asm__ __volatile__
- ("isync\n\t"
- "eieio\n\t"
- "stw %1, %0"
-#if OS(DARWIN) || CPU(PPC)
- : "=o" (lockword_)
-#else
- : "=m" (lockword_)
-#endif
- : "r" (0)
- : "memory");
-#endif
-#elif COMPILER(MSVC)
- __asm {
- mov eax, this ; store &lockword_ (which is this+0) in eax
- mov [eax], 0 ; set lockword_ to 0
- }
-#endif
- }
- // Report if we think the lock can be held by this thread.
- // When the lock is truly held by the invoking thread
- // we will always return true.
- // Indended to be used as CHECK(lock.IsHeld());
- inline bool IsHeld() const {
- return lockword_ != 0;
- }
-
- inline void Init() { lockword_ = 0; }
-
- volatile unsigned int lockword_;
-};
-
-#define SPINLOCK_INITIALIZER { 0 }
-
-static void TCMalloc_SlowLock(volatile unsigned int* lockword) {
-// Yield immediately since fast path failed
-#if OS(WINDOWS)
- Sleep(0);
-#else
- sched_yield();
-#endif
- while (true) {
- int r;
-#if COMPILER(GCC)
-#if CPU(X86) || CPU(X86_64)
- __asm__ __volatile__
- ("xchgl %0, %1"
- : "=r"(r), "=m"(*lockword)
- : "0"(1), "m"(*lockword)
- : "memory");
-
-#else
- int tmp = 1;
- __asm__ __volatile__
- ("1: lwarx %0, 0, %1\n\t"
- "stwcx. %2, 0, %1\n\t"
- "bne- 1b\n\t"
- "isync"
- : "=&r" (r), "=r" (lockword)
- : "r" (tmp), "1" (lockword)
- : "memory");
-#endif
-#elif COMPILER(MSVC)
- __asm {
- mov eax, lockword ; assign lockword into eax
- mov ebx, 1 ; assign 1 into ebx
- xchg [eax], ebx ; exchange *lockword and 1
- mov r, ebx ; store old value of *lockword in r
- }
-#endif
- if (!r) {
- return;
- }
-
- // This code was adapted from the ptmalloc2 implementation of
- // spinlocks which would sched_yield() upto 50 times before
- // sleeping once for a few milliseconds. Mike Burrows suggested
- // just doing one sched_yield() outside the loop and always
- // sleeping after that. This change helped a great deal on the
- // performance of spinlocks under high contention. A test program
- // with 10 threads on a dual Xeon (four virtual processors) went
- // from taking 30 seconds to 16 seconds.
-
- // Sleep for a few milliseconds
-#if OS(WINDOWS)
- Sleep(2);
-#else
- struct timespec tm;
- tm.tv_sec = 0;
- tm.tv_nsec = 2000001;
- nanosleep(&tm, NULL);
-#endif
- }
-}
-
-#elif OS(WINDOWS)
-
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#include <windows.h>
-
-static void TCMalloc_SlowLock(LPLONG lockword);
-
-// The following is a struct so that it can be initialized at compile time
-struct TCMalloc_SpinLock {
-
- inline void Lock() {
- if (InterlockedExchange(&m_lockword, 1))
- TCMalloc_SlowLock(&m_lockword);
- }
-
- inline void Unlock() {
- InterlockedExchange(&m_lockword, 0);
- }
-
- inline bool IsHeld() const {
- return m_lockword != 0;
- }
-
- inline void Init() { m_lockword = 0; }
-
- LONG m_lockword;
-};
-
-#define SPINLOCK_INITIALIZER { 0 }
-
-static void TCMalloc_SlowLock(LPLONG lockword) {
- Sleep(0); // Yield immediately since fast path failed
- while (InterlockedExchange(lockword, 1))
- Sleep(2);
-}
-
-#else
-
-#include <pthread.h>
-
-// Portable version
-struct TCMalloc_SpinLock {
- pthread_mutex_t private_lock_;
-
- inline void Init() {
- if (pthread_mutex_init(&private_lock_, NULL) != 0) CRASH();
- }
- inline void Finalize() {
- if (pthread_mutex_destroy(&private_lock_) != 0) CRASH();
- }
- inline void Lock() {
- if (pthread_mutex_lock(&private_lock_) != 0) CRASH();
- }
- inline void Unlock() {
- if (pthread_mutex_unlock(&private_lock_) != 0) CRASH();
- }
- bool IsHeld() {
- if (pthread_mutex_trylock(&private_lock_))
- return true;
-
- Unlock();
- return false;
- }
-};
-
-#define SPINLOCK_INITIALIZER { PTHREAD_MUTEX_INITIALIZER }
-
-#endif
-
-// Corresponding locker object that arranges to acquire a spinlock for
-// the duration of a C++ scope.
-class TCMalloc_SpinLockHolder {
- private:
- TCMalloc_SpinLock* lock_;
- public:
- inline explicit TCMalloc_SpinLockHolder(TCMalloc_SpinLock* l)
- : lock_(l) { l->Lock(); }
- inline ~TCMalloc_SpinLockHolder() { lock_->Unlock(); }
-};
-
-// Short-hands for convenient use by tcmalloc.cc
-typedef TCMalloc_SpinLock SpinLock;
-typedef TCMalloc_SpinLockHolder SpinLockHolder;
-
-#endif // TCMALLOC_INTERNAL_SPINLOCK_H__
projects / apple / javascriptcore.git / blobdiff