зеркало из https://github.com/mozilla/gecko-dev.git
155 строки
3.7 KiB
C++
155 строки
3.7 KiB
C++
/* ***** BEGIN LICENSE BLOCK *****
|
|
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
|
|
*
|
|
* The contents of this file are subject to the Mozilla Public License Version
|
|
* 1.1 (the "License"); you may not use this file except in compliance with
|
|
* the License. You may obtain a copy of the License at
|
|
* http://www.mozilla.org/MPL/
|
|
*
|
|
* Software distributed under the License is distributed on an "AS IS" basis,
|
|
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
|
|
* for the specific language governing rights and limitations under the
|
|
* License.
|
|
*
|
|
* The Original Code is [Open Source Virtual Machine.].
|
|
*
|
|
* The Initial Developer of the Original Code is
|
|
* Adobe System Incorporated.
|
|
* Portions created by the Initial Developer are Copyright (C) 2004-2006
|
|
* the Initial Developer. All Rights Reserved.
|
|
*
|
|
* Contributor(s):
|
|
* Adobe AS3 Team
|
|
*
|
|
* Alternatively, the contents of this file may be used under the terms of
|
|
* either the GNU General Public License Version 2 or later (the "GPL"), or
|
|
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
|
|
* in which case the provisions of the GPL or the LGPL are applicable instead
|
|
* of those above. If you wish to allow use of your version of this file only
|
|
* under the terms of either the GPL or the LGPL, and not to allow others to
|
|
* use your version of this file under the terms of the MPL, indicate your
|
|
* decision by deleting the provisions above and replace them with the notice
|
|
* and other provisions required by the GPL or the LGPL. If you do not delete
|
|
* the provisions above, a recipient may use your version of this file under
|
|
* the terms of any one of the MPL, the GPL or the LGPL.
|
|
*
|
|
* ***** END LICENSE BLOCK ***** */
|
|
|
|
#ifndef __GCSpinLock__
|
|
#define __GCSpinLock__
|
|
|
|
#include <pthread.h>
|
|
|
|
#define USE_X86_SPINLOCK
|
|
|
|
namespace MMgc
|
|
{
|
|
/**
|
|
* GCSpinLock is a simple spin lock class used by GCHeap to
|
|
* ensure mutually exclusive access. The GCHeap may be accessed
|
|
* by multiple threads, so this is necessary to ensure that
|
|
* the threads do not step on each other.
|
|
*/
|
|
class GCSpinLock
|
|
{
|
|
public:
|
|
#ifdef USE_X86_SPINLOCK
|
|
|
|
GCSpinLock()
|
|
{
|
|
lock = 0;
|
|
__asm__ volatile("" : : : "memory");
|
|
}
|
|
|
|
~GCSpinLock()
|
|
{
|
|
lock = 0;
|
|
__asm__ volatile("" : : : "memory");
|
|
}
|
|
|
|
inline void Acquire()
|
|
{
|
|
while ( X86_TestAndSet(&lock, 1) != 0 ) {
|
|
X86_Pause();
|
|
}
|
|
__asm__ volatile("" : : : "memory");
|
|
}
|
|
|
|
inline void Release()
|
|
{
|
|
__asm__ volatile("" : : : "memory");
|
|
lock = 0;
|
|
}
|
|
|
|
private:
|
|
|
|
inline int X86_TestAndSet(volatile int *ptr, int val) {
|
|
__asm__ volatile("xchgl %0, (%2)" :"=r"(val) : "0"(val), "r"(ptr));
|
|
return val;
|
|
}
|
|
|
|
inline void X86_Pause(void)
|
|
{
|
|
__asm__ volatile("pause");
|
|
}
|
|
|
|
volatile int lock;
|
|
|
|
#else // USE_X86_SPINLOCK
|
|
|
|
GCSpinLock()
|
|
{
|
|
pthread_spin_init( &m1, 0 );
|
|
}
|
|
|
|
~GCSpinLock()
|
|
{
|
|
pthread_spin_destroy( &m1 );
|
|
}
|
|
|
|
inline void Acquire()
|
|
{
|
|
pthread_spin_lock( &m1 );
|
|
}
|
|
|
|
inline void Release()
|
|
{
|
|
pthread_spin_unlock( &m1 );
|
|
}
|
|
|
|
private:
|
|
pthread_spinlock_t m1;
|
|
|
|
#endif // USE_X86_SPINLOCK
|
|
};
|
|
|
|
/**
|
|
* GCAcquireSpinlock is a convenience class which acquires
|
|
* the specified spinlock at construct time, then releases
|
|
* the spinlock at desruct time. The single statement
|
|
*
|
|
* GCAcquireSpinlock acquire(spinlock);
|
|
*
|
|
* ... will acquire the spinlock at the top of the function
|
|
* and release it at the end. This makes for less error-prone
|
|
* code than explicit acquire/release.
|
|
*/
|
|
class GCAcquireSpinlock
|
|
{
|
|
public:
|
|
GCAcquireSpinlock(GCSpinLock& spinlock) : m_spinlock(spinlock)
|
|
{
|
|
m_spinlock.Acquire();
|
|
}
|
|
~GCAcquireSpinlock()
|
|
{
|
|
m_spinlock.Release();
|
|
}
|
|
|
|
private:
|
|
GCSpinLock& m_spinlock;
|
|
};
|
|
}
|
|
|
|
#endif /* __GCSpinLock__ */
|