Source/JavaScriptCore/dfg/DFGDesiredWatchpoints.h

/*
 * Copyright (C) 2013 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. 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. 
 */

#ifndef DFGDesiredWatchpoints_h
#define DFGDesiredWatchpoints_h

#include <wtf/Platform.h>

#if ENABLE(DFG_JIT)

#include "Watchpoint.h"
#include <wtf/HashMap.h>
#include <wtf/Noncopyable.h>
#include <wtf/Vector.h>

namespace JSC { namespace DFG {

template<typename WatchpointSetType>
struct WatchpointForGenericWatchpointSet {
    WatchpointForGenericWatchpointSet()
        : m_watchpoint(0)
        , m_set(0)
    {
    }
    
    WatchpointForGenericWatchpointSet(Watchpoint* watchpoint, WatchpointSetType* set)
        : m_watchpoint(watchpoint)
        , m_set(set)
    {
    }
    
    Watchpoint* m_watchpoint;
    WatchpointSetType* m_set;
};

typedef WatchpointForGenericWatchpointSet<WatchpointSet> WatchpointForWatchpointSet;
typedef WatchpointForGenericWatchpointSet<InlineWatchpointSet> WatchpointForInlineWatchpointSet;

template<typename WatchpointSetType>
class GenericDesiredWatchpoints {
    WTF_MAKE_NONCOPYABLE(GenericDesiredWatchpoints);
#if !ASSERT_DISABLED
    typedef HashMap<WatchpointSetType*, bool> StateMap;
#endif
public:
    GenericDesiredWatchpoints()
        : m_reallyAdded(false)
    {
    }
    
    void addLazily(const WatchpointForGenericWatchpointSet<WatchpointSetType>& watchpoint)
    {
        m_watchpoints.append(watchpoint);
    }
    
    void reallyAdd()
    {
        RELEASE_ASSERT(!m_reallyAdded);
        for (unsigned i = m_watchpoints.size(); i--;)
            m_watchpoints[i].m_set->add(m_watchpoints[i].m_watchpoint);
        m_reallyAdded = true;
    }
    
    bool areStillValid() const
    {
        for (unsigned i = m_watchpoints.size(); i--;) {
            if (m_watchpoints[i].m_set->hasBeenInvalidated())
                return false;
        }
        return true;
    }
    
#if ASSERT_DISABLED
    bool isStillValid(WatchpointSetType* set)
    {
        return set->isStillValid();
    }
    
    bool shouldAssumeMixedState(WatchpointSetType*)
    {
        return true;
    }
#else
    bool isStillValid(WatchpointSetType* set)
    {
        bool result = set->isStillValid();
        m_firstKnownState.add(set, result);
        return result;
    }
    
    bool shouldAssumeMixedState(WatchpointSetType* set)
    {
        typename StateMap::iterator iter = m_firstKnownState.find(set);
        if (iter == m_firstKnownState.end())
            return false;
        
        return iter->value != set->isStillValid();
    }
#endif
    
    bool isValidOrMixed(WatchpointSetType* set)
    {
        return isStillValid(set) || shouldAssumeMixedState(set);
    }

private:
    Vector<WatchpointForGenericWatchpointSet<WatchpointSetType>> m_watchpoints;
#if !ASSERT_DISABLED
    StateMap m_firstKnownState;
#endif
    bool m_reallyAdded;
};

class DesiredWatchpoints {
public:
    DesiredWatchpoints();
    ~DesiredWatchpoints();
    
    void addLazily(Watchpoint*, WatchpointSet*);
    void addLazily(Watchpoint*, InlineWatchpointSet&);
    
    void reallyAdd();
    
    bool areStillValid() const;
    
    bool isStillValid(WatchpointSet* set)
    {
        return m_sets.isStillValid(set);
    }
    bool isStillValid(InlineWatchpointSet& set)
    {
        return m_inlineSets.isStillValid(&set);
    }
    bool shouldAssumeMixedState(WatchpointSet* set)
    {
        return m_sets.shouldAssumeMixedState(set);
    }
    bool shouldAssumeMixedState(InlineWatchpointSet& set)
    {
        return m_inlineSets.shouldAssumeMixedState(&set);
    }
    bool isValidOrMixed(WatchpointSet* set)
    {
        return m_sets.isValidOrMixed(set);
    }
    bool isValidOrMixed(InlineWatchpointSet& set)
    {
        return m_inlineSets.isValidOrMixed(&set);
    }
    
private:
    GenericDesiredWatchpoints<WatchpointSet> m_sets;
    GenericDesiredWatchpoints<InlineWatchpointSet> m_inlineSets;
};

} } // namespace JSC::DFG

#endif // ENABLE(DFG_JIT)

#endif // DFGDesiredWatchpoints_h