src/third_party/WebKit/Source/JavaScriptCore/bytecode/StructureStubInfo.h

/*
 * Copyright (C) 2008, 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.
 *
 * 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 StructureStubInfo_h
#define StructureStubInfo_h

#include <wtf/Platform.h>

#if ENABLE(JIT)

#include "CodeOrigin.h"
#include "DFGRegisterSet.h"
#include "Instruction.h"
#include "JITStubRoutine.h"
#include "MacroAssembler.h"
#include "Opcode.h"
#include "Structure.h"
#include "StructureStubClearingWatchpoint.h"
#include <wtf/OwnPtr.h>

namespace JSC {

    class PolymorphicPutByIdList;

    enum AccessType {
        access_get_by_id_self,
        access_get_by_id_proto,
        access_get_by_id_chain,
        access_get_by_id_self_list,
        access_get_by_id_proto_list,
        access_put_by_id_transition_normal,
        access_put_by_id_transition_direct,
        access_put_by_id_replace,
        access_put_by_id_list,
        access_unset,
        access_get_by_id_generic,
        access_put_by_id_generic,
        access_get_array_length,
        access_get_string_length,
    };

    inline bool isGetByIdAccess(AccessType accessType)
    {
        switch (accessType) {
        case access_get_by_id_self:
        case access_get_by_id_proto:
        case access_get_by_id_chain:
        case access_get_by_id_self_list:
        case access_get_by_id_proto_list:
        case access_get_by_id_generic:
        case access_get_array_length:
        case access_get_string_length:
            return true;
        default:
            return false;
        }
    }
    
    inline bool isPutByIdAccess(AccessType accessType)
    {
        switch (accessType) {
        case access_put_by_id_transition_normal:
        case access_put_by_id_transition_direct:
        case access_put_by_id_replace:
        case access_put_by_id_list:
        case access_put_by_id_generic:
            return true;
        default:
            return false;
        }
    }

    struct StructureStubInfo {
        StructureStubInfo()
            : accessType(access_unset)
            , seen(false)
        {
        }

        void initGetByIdSelf(JSGlobalData& globalData, JSCell* owner, Structure* baseObjectStructure)
        {
            accessType = access_get_by_id_self;

            u.getByIdSelf.baseObjectStructure.set(globalData, owner, baseObjectStructure);
        }

        void initGetByIdProto(JSGlobalData& globalData, JSCell* owner, Structure* baseObjectStructure, Structure* prototypeStructure, bool isDirect)
        {
            accessType = access_get_by_id_proto;

            u.getByIdProto.baseObjectStructure.set(globalData, owner, baseObjectStructure);
            u.getByIdProto.prototypeStructure.set(globalData, owner, prototypeStructure);
            u.getByIdProto.isDirect = isDirect;
        }

        void initGetByIdChain(JSGlobalData& globalData, JSCell* owner, Structure* baseObjectStructure, StructureChain* chain, unsigned count, bool isDirect)
        {
            accessType = access_get_by_id_chain;

            u.getByIdChain.baseObjectStructure.set(globalData, owner, baseObjectStructure);
            u.getByIdChain.chain.set(globalData, owner, chain);
            u.getByIdChain.count = count;
            u.getByIdChain.isDirect = isDirect;
        }

        void initGetByIdSelfList(PolymorphicAccessStructureList* structureList, int listSize)
        {
            accessType = access_get_by_id_self_list;

            u.getByIdSelfList.structureList = structureList;
            u.getByIdSelfList.listSize = listSize;
        }

        void initGetByIdProtoList(PolymorphicAccessStructureList* structureList, int listSize)
        {
            accessType = access_get_by_id_proto_list;

            u.getByIdProtoList.structureList = structureList;
            u.getByIdProtoList.listSize = listSize;
        }

        // PutById*

        void initPutByIdTransition(JSGlobalData& globalData, JSCell* owner, Structure* previousStructure, Structure* structure, StructureChain* chain, bool isDirect)
        {
            if (isDirect)
                accessType = access_put_by_id_transition_direct;
            else
                accessType = access_put_by_id_transition_normal;

            u.putByIdTransition.previousStructure.set(globalData, owner, previousStructure);
            u.putByIdTransition.structure.set(globalData, owner, structure);
            u.putByIdTransition.chain.set(globalData, owner, chain);
        }

        void initPutByIdReplace(JSGlobalData& globalData, JSCell* owner, Structure* baseObjectStructure)
        {
            accessType = access_put_by_id_replace;
    
            u.putByIdReplace.baseObjectStructure.set(globalData, owner, baseObjectStructure);
        }
        
        void initPutByIdList(PolymorphicPutByIdList* list)
        {
            accessType = access_put_by_id_list;
            u.putByIdList.list = list;
        }
        
        void reset()
        {
            deref();
            accessType = access_unset;
            stubRoutine.clear();
            watchpoints.clear();
        }

        void deref();

        bool visitWeakReferences();
        
        bool seenOnce()
        {
            return seen;
        }

        void setSeen()
        {
            seen = true;
        }
        
        StructureStubClearingWatchpoint* addWatchpoint(CodeBlock* codeBlock)
        {
            return WatchpointsOnStructureStubInfo::ensureReferenceAndAddWatchpoint(
                watchpoints, codeBlock, this);
        }
        
        unsigned bytecodeIndex;

        int8_t accessType;
        int8_t seen;

#if ENABLE(DFG_JIT)
        CodeOrigin codeOrigin;
#endif // ENABLE(DFG_JIT)

        union {
            struct {
                int8_t registersFlushed;
                int8_t baseGPR;
#if USE(JSVALUE32_64)
                int8_t valueTagGPR;
#endif
                int8_t valueGPR;
                DFG::RegisterSetPOD usedRegisters;
                int32_t deltaCallToDone;
                int32_t deltaCallToStorageLoad;
                int32_t deltaCallToStructCheck;
                int32_t deltaCallToSlowCase;
                int32_t deltaCheckImmToCall;
#if USE(JSVALUE64)
                int32_t deltaCallToLoadOrStore;
#else
                int32_t deltaCallToTagLoadOrStore;
                int32_t deltaCallToPayloadLoadOrStore;
#endif
            } dfg;
            struct {
                union {
                    struct {
                        int16_t structureToCompare;
                        int16_t structureCheck;
                        int16_t propertyStorageLoad;
#if USE(JSVALUE64)
                        int16_t displacementLabel;
#else
                        int16_t displacementLabel1;
                        int16_t displacementLabel2;
#endif
                        int16_t putResult;
                        int16_t coldPathBegin;
                    } get;
                    struct {
                        int16_t structureToCompare;
                        int16_t propertyStorageLoad;
#if USE(JSVALUE64)
                        int16_t displacementLabel;
#else
                        int16_t displacementLabel1;
                        int16_t displacementLabel2;
#endif
                    } put;
                } u;
                int16_t methodCheckProtoObj;
                int16_t methodCheckProtoStructureToCompare;
                int16_t methodCheckPutFunction;
            } baseline;
        } patch;

        union {
            struct {
                // It would be unwise to put anything here, as it will surely be overwritten.
            } unset;
            struct {
                WriteBarrierBase<Structure> baseObjectStructure;
            } getByIdSelf;
            struct {
                WriteBarrierBase<Structure> baseObjectStructure;
                WriteBarrierBase<Structure> prototypeStructure;
                bool isDirect;
            } getByIdProto;
            struct {
                WriteBarrierBase<Structure> baseObjectStructure;
                WriteBarrierBase<StructureChain> chain;
                unsigned count : 31;
                bool isDirect : 1;
            } getByIdChain;
            struct {
                PolymorphicAccessStructureList* structureList;
                int listSize;
            } getByIdSelfList;
            struct {
                PolymorphicAccessStructureList* structureList;
                int listSize;
            } getByIdProtoList;
            struct {
                WriteBarrierBase<Structure> previousStructure;
                WriteBarrierBase<Structure> structure;
                WriteBarrierBase<StructureChain> chain;
            } putByIdTransition;
            struct {
                WriteBarrierBase<Structure> baseObjectStructure;
            } putByIdReplace;
            struct {
                PolymorphicPutByIdList* list;
            } putByIdList;
        } u;

        RefPtr<JITStubRoutine> stubRoutine;
        CodeLocationCall callReturnLocation;
        CodeLocationLabel hotPathBegin;
        RefPtr<WatchpointsOnStructureStubInfo> watchpoints;
    };

    inline void* getStructureStubInfoReturnLocation(StructureStubInfo* structureStubInfo)
    {
        return structureStubInfo->callReturnLocation.executableAddress();
    }

    inline unsigned getStructureStubInfoBytecodeIndex(StructureStubInfo* structureStubInfo)
    {
        return structureStubInfo->bytecodeIndex;
    }

} // namespace JSC

#endif // ENABLE(JIT)

#endif // StructureStubInfo_h