Source/JavaScriptCore/bytecode/CallLinkInfo.cpp

/*
 * Copyright (C) 2012, 2013, 2014 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. 
 */

#include "config.h"
#include "CallLinkInfo.h"

#include "DFGOperations.h"
#include "DFGThunks.h"
#include "JSCInlines.h"
#include "RepatchBuffer.h"
#include <wtf/NeverDestroyed.h>

#if ENABLE(JIT)
namespace JSC {

void CallLinkInfo::unlink(RepatchBuffer& repatchBuffer)
{
    ASSERT(isLinked());
    
    if (Options::showDisassembly())
        dataLog("Unlinking call from ", callReturnLocation, " to ", pointerDump(repatchBuffer.codeBlock()), "\n");

    repatchBuffer.revertJumpReplacementToBranchPtrWithPatch(RepatchBuffer::startOfBranchPtrWithPatchOnRegister(hotPathBegin), static_cast<MacroAssembler::RegisterID>(calleeGPR), 0);
    repatchBuffer.relink(
        callReturnLocation,
        repatchBuffer.codeBlock()->vm()->getCTIStub(linkThunkGeneratorFor(
            (callType == Construct || callType == ConstructVarargs)? CodeForConstruct : CodeForCall,
            isFTL ? MustPreserveRegisters : RegisterPreservationNotRequired)).code());
    hasSeenShouldRepatch = false;
    callee.clear();
    stub.clear();

    // It will be on a list if the callee has a code block.
    if (isOnList())
        remove();
}

void CallLinkInfo::visitWeak(RepatchBuffer& repatchBuffer)
{
    if (isLinked()) {
        if (stub) {
            if (!Heap::isMarked(stub->executable())) {
                if (Options::verboseOSR()) {
                    dataLog(
                        "Clearing closure call from ", *repatchBuffer.codeBlock(), " to ",
                        stub->executable()->hashFor(specializationKind()),
                        ", stub routine ", RawPointer(stub.get()), ".\n");
                }
                unlink(repatchBuffer);
            }
        } else if (!Heap::isMarked(callee.get())) {
            if (Options::verboseOSR()) {
                dataLog(
                    "Clearing call from ", *repatchBuffer.codeBlock(), " to ",
                    RawPointer(callee.get()), " (",
                    callee.get()->executable()->hashFor(specializationKind()),
                    ").\n");
            }
            unlink(repatchBuffer);
        }
    }
    if (!!lastSeenCallee && !Heap::isMarked(lastSeenCallee.get()))
        lastSeenCallee.clear();
    
    if (callEdgeProfile) {
        WTF::loadLoadFence();
        callEdgeProfile->visitWeak();
    }
}

CallLinkInfo& CallLinkInfo::dummy()
{
    static NeverDestroyed<CallLinkInfo> dummy;
    return dummy;
}

} // namespace JSC
#endif // ENABLE(JIT)