/*
 * Copyright (C) 2017-2021 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. 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 INC. 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 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.
 */

#include "config.h"
#include "MarkStackMergingConstraint.h"

#include "GCSegmentedArrayInlines.h"
#include "JSCInlines.h"
#include <wtf/TZoneMallocInlines.h>

namespace JSC {

WTF_MAKE_TZONE_ALLOCATED_IMPL(MarkStackMergingConstraint);

MarkStackMergingConstraint::MarkStackMergingConstraint(JSC::Heap& heap)
    : MarkingConstraint("Msm"_s, "Mark Stack Merging"_s, ConstraintVolatility::GreyedByExecution)
    , m_heap(heap)
{
}

MarkStackMergingConstraint::~MarkStackMergingConstraint() = default;

double MarkStackMergingConstraint::quickWorkEstimate(SlotVisitor&)
{
    return m_heap.m_mutatorMarkStack->size() + m_heap.m_raceMarkStack->size();
}

void MarkStackMergingConstraint::prepareToExecuteImpl(const AbstractLocker&, AbstractSlotVisitor& visitor)
{
    // Logging the work here ensures that the constraint solver knows that it doesn't need to produce
    // anymore work.
    size_t size = m_heap.m_mutatorMarkStack->size() + m_heap.m_raceMarkStack->size();
    visitor.addToVisitCount(size);
    
    dataLogIf(Options::logGC(), "(", size, ")");
}

template<typename Visitor>
void MarkStackMergingConstraint::executeImplImpl(Visitor& visitor)
{
    // We want to skip this constraint for the GC verifier because:
    // 1. There should be no mutator marking action between the End phase and verifyGC().
    //    Hence, we can ignore these stacks.
    // 2. The End phase explicitly calls iterateExecutingAndCompilingCodeBlocks()
    //    to add executing CodeBlocks to m_heap.m_mutatorMarkStack. We want to
    //    leave those unperturbed.
    if (m_heap.m_isMarkingForGCVerifier)
        return;

    m_heap.m_mutatorMarkStack->transferTo(visitor.mutatorMarkStack());
    m_heap.m_raceMarkStack->transferTo(visitor.mutatorMarkStack());
}

void MarkStackMergingConstraint::executeImpl(AbstractSlotVisitor& visitor) { executeImplImpl(visitor); }
void MarkStackMergingConstraint::executeImpl(SlotVisitor& visitor) { executeImplImpl(visitor); }

} // namespace JSC

