/*

 * Copyright (C) 2008 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

 * 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 Instruction_h

#define Instruction_h

#include "MacroAssembler.h"

#include "Opcode.h"

#include "Structure.h"

#include <wtf/VectorTraits.h>

#define POLYMORPHIC_LIST_CACHE_SIZE 8

namespace JSC {

    // *Sigh*, If the JIT is enabled we need to track the stubRountine (of type CodeLocationLabel),

    // If the JIT is not in use we don't actually need the variable (that said, if the JIT is not in use we don't

    // curently actually use PolymorphicAccessStructureLists, which we should).  Anyway, this seems like the best

    // solution for now - will need to something smarter if/when we actually want mixed-mode operation.

#if ENABLE(JIT)

    typedef CodeLocationLabel PolymorphicAccessStructureListStubRoutineType;

#else

    typedef void* PolymorphicAccessStructureListStubRoutineType;

#endif

    class JSCell;

    class Structure;

    class StructureChain;

    // Structure used by op_get_by_id_self_list and op_get_by_id_proto_list instruction to hold data off the main opcode stream.

    struct PolymorphicAccessStructureList : FastAllocBase {

        struct PolymorphicStubInfo {

            bool isChain;

            PolymorphicAccessStructureListStubRoutineType stubRoutine;

            Structure* base;

            union {

                Structure* proto;

                StructureChain* chain;

            } u;

            void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base)

            {

                stubRoutine = _stubRoutine;

                base = _base;

                u.proto = 0;

                isChain = false;

            }

            void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base, Structure* _proto)

            {

                stubRoutine = _stubRoutine;

                base = _base;

                u.proto = _proto;

                isChain = false;

            }

            void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base, StructureChain* _chain)

            {

                stubRoutine = _stubRoutine;

                base = _base;

                u.chain = _chain;

                isChain = true;

            }

        } list[POLYMORPHIC_LIST_CACHE_SIZE];

        PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase)

        {

            list[0].set(stubRoutine, firstBase);

        }

        PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase, Structure* firstProto)

        {

            list[0].set(stubRoutine, firstBase, firstProto);

        }

        PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase, StructureChain* firstChain)

        {

            list[0].set(stubRoutine, firstBase, firstChain);

        }

        void derefStructures(int count)

        {

            for (int i = 0; i < count; ++i) {

                PolymorphicStubInfo& info = list[i];

                ASSERT(info.base);

                info.base->deref();

                if (info.u.proto) {

                    if (info.isChain)

                        info.u.chain->deref();

                    else

                        info.u.proto->deref();

                }

            }

        }

    };

    struct Instruction {

        Instruction(Opcode opcode)

        {

#if !HAVE(COMPUTED_GOTO)

            // We have to initialize one of the pointer members to ensure that

            // the entire struct is initialized, when opcode is not a pointer.

            u.jsCell = 0;

#endif

            u.opcode = opcode;

        }

        Instruction(int operand)

        {

            // We have to initialize one of the pointer members to ensure that

            // the entire struct is initialized in 64-bit.

            u.jsCell = 0;

            u.operand = operand;

        }

        Instruction(Structure* structure) { u.structure = structure; }

        Instruction(StructureChain* structureChain) { u.structureChain = structureChain; }

        Instruction(JSCell* jsCell) { u.jsCell = jsCell; }

        Instruction(PolymorphicAccessStructureList* polymorphicStructures) { u.polymorphicStructures = polymorphicStructures; }

        union {

            Opcode opcode;

            int operand;

            Structure* structure;

            StructureChain* structureChain;

            JSCell* jsCell;

            PolymorphicAccessStructureList* polymorphicStructures;

        } u;

    };

} // namespace JSC

namespace WTF {

    template<> struct VectorTraits<JSC::Instruction> : VectorTraitsBase<true, JSC::Instruction> { };

} // namespace WTF

#endif // Instruction_h