Source/heap/ThreadState.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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#include "config.h"
#include "heap/ThreadState.h"

#include "wtf/ThreadingPrimitives.h"

namespace WebCore {

WTF::ThreadSpecific<ThreadState*>* ThreadState::s_threadSpecific = 0;
uint8_t ThreadState::s_mainThreadStateStorage[sizeof(ThreadState)];

static Mutex& threadAttachMutex()
{
    AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
    return mutex;
}

void ThreadState::init(intptr_t* startOfStack)
{
    s_threadSpecific = new WTF::ThreadSpecific<ThreadState*>();
    new(s_mainThreadStateStorage) ThreadState(startOfStack);
    attachedThreads().add(mainThreadState());
}

void ThreadState::shutdown()
{
    mainThreadState()->~ThreadState();
}

void ThreadState::attach(intptr_t* startOfStack)
{
    MutexLocker locker(threadAttachMutex());
    ThreadState* state = new ThreadState(startOfStack);
    attachedThreads().add(state);
}

void ThreadState::detach()
{
    ThreadState* state = current();
    MutexLocker locker(threadAttachMutex());
    attachedThreads().remove(state);
    delete state;
}

ThreadState::ThreadState(intptr_t* startOfStack)
    : m_thread(currentThread())
    , m_startOfStack(startOfStack)
{
    ASSERT(!**s_threadSpecific);
    **s_threadSpecific = this;

    // FIXME: This is to silence clang that complains about unused private
    // member. Remove once we implement stack scanning that uses it.
    (void) m_startOfStack;
}

ThreadState::~ThreadState()
{
    checkThread();
    **s_threadSpecific = 0;
}

ThreadState::AttachedThreadStateSet& ThreadState::attachedThreads()
{
    DEFINE_STATIC_LOCAL(AttachedThreadStateSet, threads, ());
    return threads;
}

}