Source/JavaScriptCore/bytecode/Watchpoint.cpp

/*
 * Copyright (C) 2012 Apple 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:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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
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 */

#include "config.h"
#include "Watchpoint.h"

#include "LinkBuffer.h"

namespace JSC {

Watchpoint::~Watchpoint()
{
    if (isOnList())
        remove();
}

void Watchpoint::correctLabels(LinkBuffer& linkBuffer)
{
    MacroAssembler::Label label;
    label.m_label.m_offset = m_source;
    m_source = bitwise_cast<uintptr_t>(linkBuffer.locationOf(label).dataLocation());
    label.m_label.m_offset = m_destination;
    m_destination = bitwise_cast<uintptr_t>(linkBuffer.locationOf(label).dataLocation());
}

void Watchpoint::fire()
{
    MacroAssembler::replaceWithJump(
        CodeLocationLabel(bitwise_cast<void*>(m_source)),
        CodeLocationLabel(bitwise_cast<void*>(m_destination)));
    if (isOnList())
        remove();
}

WatchpointSet::WatchpointSet()
    : m_isWatched(false)
    , m_isInvalidated(false)
{
}

WatchpointSet::~WatchpointSet()
{
    // Fire all watchpoints. This is necessary because it is possible, say with
    // structure watchpoints, for the watchpoint set owner to die while the
    // watchpoint owners are still live.
    fireAllWatchpoints();
}

void WatchpointSet::add(Watchpoint* watchpoint)
{
    if (!watchpoint)
        return;
    m_set.push(watchpoint);
    m_isWatched = true;
}

void WatchpointSet::notifyWriteSlow()
{
    ASSERT(m_isWatched);
    
    fireAllWatchpoints();
    m_isWatched = false;
    m_isInvalidated = true;
}

void WatchpointSet::fireAllWatchpoints()
{
    while (!m_set.isEmpty())
        m_set.begin()->fire();
}

} // namespace JSC