/*

 * Copyright (C) 2008, 2009 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"

#if ENABLE(JIT)

#if !USE(JSVALUE32_64)

#include "JIT.h"

#include "CodeBlock.h"

#include "GetterSetter.h"

#include "JITInlineMethods.h"

#include "JITStubCall.h"

#include "JSArray.h"

#include "JSFunction.h"

#include "JSPropertyNameIterator.h"

#include "Interpreter.h"

#include "LinkBuffer.h"

#include "RepatchBuffer.h"

#include "ResultType.h"

#include "SamplingTool.h"

#ifndef NDEBUG

#include <stdio.h>

#endif

using namespace std;

namespace JSC {

JIT::CodePtr JIT::stringGetByValStubGenerator(JSGlobalData* globalData, ExecutablePool* pool)

{

    JSInterfaceJIT jit;

    JumpList failures;

    failures.append(jit.branchPtr(NotEqual, Address(regT0), ImmPtr(globalData->jsStringVPtr)));

    failures.append(jit.branchTest32(NonZero, Address(regT0, OBJECT_OFFSETOF(JSString, m_fiberCount))));

    // Load string length to regT1, and start the process of loading the data pointer into regT0

    jit.load32(Address(regT0, ThunkHelpers::jsStringLengthOffset()), regT2);

    jit.loadPtr(Address(regT0, ThunkHelpers::jsStringValueOffset()), regT0);

    jit.loadPtr(Address(regT0, ThunkHelpers::stringImplDataOffset()), regT0);

    // Do an unsigned compare to simultaneously filter negative indices as well as indices that are too large

    failures.append(jit.branch32(AboveOrEqual, regT1, regT2));

    // Load the character

    jit.load16(BaseIndex(regT0, regT1, TimesTwo, 0), regT0);

    failures.append(jit.branch32(AboveOrEqual, regT0, Imm32(0x100)));

    jit.move(ImmPtr(globalData->smallStrings.singleCharacterStrings()), regT1);

    jit.loadPtr(BaseIndex(regT1, regT0, ScalePtr, 0), regT0);

    jit.ret();

    failures.link(&jit);

    jit.move(Imm32(0), regT0);

    jit.ret();

    LinkBuffer patchBuffer(&jit, pool);

    return patchBuffer.finalizeCode().m_code;

}

void JIT::emit_op_get_by_val(Instruction* currentInstruction)

{

    unsigned dst = currentInstruction[1].u.operand;

    unsigned base = currentInstruction[2].u.operand;

    unsigned property = currentInstruction[3].u.operand;

    emitGetVirtualRegisters(base, regT0, property, regT1);

    emitJumpSlowCaseIfNotImmediateInteger(regT1);

#if USE(JSVALUE64)

    // This is technically incorrect - we're zero-extending an int32.  On the hot path this doesn't matter.

    // We check the value as if it was a uint32 against the m_vectorLength - which will always fail if

    // number was signed since m_vectorLength is always less than intmax (since the total allocation

    // size is always less than 4Gb).  As such zero extending wil have been correct (and extending the value

    // to 64-bits is necessary since it's used in the address calculation.  We zero extend rather than sign

    // extending since it makes it easier to re-tag the value in the slow case.

    zeroExtend32ToPtr(regT1, regT1);

#else

    emitFastArithImmToInt(regT1);

#endif

    emitJumpSlowCaseIfNotJSCell(regT0, base);

    addSlowCase(branchPtr(NotEqual, Address(regT0), ImmPtr(m_globalData->jsArrayVPtr)));

    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSArray, m_storage)), regT2);

    addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, OBJECT_OFFSETOF(JSArray, m_vectorLength))));

    loadPtr(BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])), regT0);

    addSlowCase(branchTestPtr(Zero, regT0));

    emitPutVirtualRegister(dst);

}

void JIT::emitSlow_op_get_by_val(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)

{

    unsigned dst = currentInstruction[1].u.operand;

    unsigned base = currentInstruction[2].u.operand;

    unsigned property = currentInstruction[3].u.operand;

    linkSlowCase(iter); // property int32 check

    linkSlowCaseIfNotJSCell(iter, base); // base cell check

    Jump nonCell = jump();

    linkSlowCase(iter); // base array check

    Jump notString = branchPtr(NotEqual, Address(regT0), ImmPtr(m_globalData->jsStringVPtr));

    emitNakedCall(m_globalData->getCTIStub(stringGetByValStubGenerator));

    Jump failed = branchTestPtr(Zero, regT0);

    emitPutVirtualRegister(dst, regT0);

    emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_get_by_val));

    failed.link(this);

    notString.link(this);

    nonCell.link(this);

    linkSlowCase(iter); // vector length check

    linkSlowCase(iter); // empty value

    JITStubCall stubCall(this, cti_op_get_by_val);

    stubCall.addArgument(base, regT2);

    stubCall.addArgument(property, regT2);

    stubCall.call(dst);

}

void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, RegisterID structure, RegisterID offset, RegisterID scratch)

{

    ASSERT(sizeof(((Structure*)0)->m_propertyStorageCapacity) == sizeof(int32_t));

    ASSERT(sizeof(JSObject::inlineStorageCapacity) == sizeof(int32_t));

    Jump notUsingInlineStorage = branch32(NotEqual, Address(structure, OBJECT_OFFSETOF(Structure, m_propertyStorageCapacity)), Imm32(JSObject::inlineStorageCapacity));

    loadPtr(BaseIndex(base, offset, ScalePtr, OBJECT_OFFSETOF(JSObject, m_inlineStorage)), result);

    Jump finishedLoad = jump();

    notUsingInlineStorage.link(this);

    loadPtr(Address(base, OBJECT_OFFSETOF(JSObject, m_externalStorage)), scratch);

    loadPtr(BaseIndex(scratch, offset, ScalePtr, 0), result);

    finishedLoad.link(this);

}

void JIT::emit_op_get_by_pname(Instruction* currentInstruction)

{

    unsigned dst = currentInstruction[1].u.operand;

    unsigned base = currentInstruction[2].u.operand;

    unsigned property = currentInstruction[3].u.operand;

    unsigned expected = currentInstruction[4].u.operand;

    unsigned iter = currentInstruction[5].u.operand;

    unsigned i = currentInstruction[6].u.operand;

    emitGetVirtualRegister(property, regT0);

    addSlowCase(branchPtr(NotEqual, regT0, addressFor(expected)));

    emitGetVirtualRegisters(base, regT0, iter, regT1);

    emitJumpSlowCaseIfNotJSCell(regT0, base);

    // Test base's structure

    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), regT2);

    addSlowCase(branchPtr(NotEqual, regT2, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_cachedStructure))));

    load32(addressFor(i), regT3);

    sub32(Imm32(1), regT3);

    addSlowCase(branch32(AboveOrEqual, regT3, Address(regT1, OBJECT_OFFSETOF(JSPropertyNameIterator, m_numCacheableSlots))));

    compileGetDirectOffset(regT0, regT0, regT2, regT3, regT1);

    emitPutVirtualRegister(dst, regT0);

}

void JIT::emitSlow_op_get_by_pname(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)

{

    unsigned dst = currentInstruction[1].u.operand;

    unsigned base = currentInstruction[2].u.operand;

    unsigned property = currentInstruction[3].u.operand;

    linkSlowCase(iter);

    linkSlowCaseIfNotJSCell(iter, base);

    linkSlowCase(iter);

    linkSlowCase(iter);

    JITStubCall stubCall(this, cti_op_get_by_val);

    stubCall.addArgument(base, regT2);

    stubCall.addArgument(property, regT2);

    stubCall.call(dst);

}

void JIT::emit_op_put_by_val(Instruction* currentInstruction)

{

    unsigned base = currentInstruction[1].u.operand;

    unsigned property = currentInstruction[2].u.operand;

    unsigned value = currentInstruction[3].u.operand;

    emitGetVirtualRegisters(base, regT0, property, regT1);

    emitJumpSlowCaseIfNotImmediateInteger(regT1);

#if USE(JSVALUE64)

    // See comment in op_get_by_val.

    zeroExtend32ToPtr(regT1, regT1);

#else

    emitFastArithImmToInt(regT1);

#endif

    emitJumpSlowCaseIfNotJSCell(regT0, base);

    addSlowCase(branchPtr(NotEqual, Address(regT0), ImmPtr(m_globalData->jsArrayVPtr)));

    addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, OBJECT_OFFSETOF(JSArray, m_vectorLength))));

    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSArray, m_storage)), regT2);

    Jump empty = branchTestPtr(Zero, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));

    Label storeResult(this);

    emitGetVirtualRegister(value, regT0);

    storePtr(regT0, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));

    Jump end = jump();

    empty.link(this);

    add32(Imm32(1), Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector)));

    branch32(Below, regT1, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length))).linkTo(storeResult, this);

    move(regT1, regT0);

    add32(Imm32(1), regT0);

    store32(regT0, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length)));

    jump().linkTo(storeResult, this);

    end.link(this);

}

void JIT::emit_op_put_by_index(Instruction* currentInstruction)

{

    JITStubCall stubCall(this, cti_op_put_by_index);

    stubCall.addArgument(currentInstruction[1].u.operand, regT2);

    stubCall.addArgument(Imm32(currentInstruction[2].u.operand));

    stubCall.addArgument(currentInstruction[3].u.operand, regT2);

    stubCall.call();

}

void JIT::emit_op_put_getter(Instruction* currentInstruction)

{

    JITStubCall stubCall(this, cti_op_put_getter);

    stubCall.addArgument(currentInstruction[1].u.operand, regT2);

    stubCall.addArgument(ImmPtr(&m_codeBlock->identifier(currentInstruction[2].u.operand)));

    stubCall.addArgument(currentInstruction[3].u.operand, regT2);

    stubCall.call();

}

void JIT::emit_op_put_setter(Instruction* currentInstruction)

{

    JITStubCall stubCall(this, cti_op_put_setter);

    stubCall.addArgument(currentInstruction[1].u.operand, regT2);

    stubCall.addArgument(ImmPtr(&m_codeBlock->identifier(currentInstruction[2].u.operand)));

    stubCall.addArgument(currentInstruction[3].u.operand, regT2);

    stubCall.call();

}

void JIT::emit_op_del_by_id(Instruction* currentInstruction)

{

    JITStubCall stubCall(this, cti_op_del_by_id);

    stubCall.addArgument(currentInstruction[2].u.operand, regT2);

    stubCall.addArgument(ImmPtr(&m_codeBlock->identifier(currentInstruction[3].u.operand)));

    stubCall.call(currentInstruction[1].u.operand);

}

#if !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)

/* ------------------------------ BEGIN: !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS) ------------------------------ */

// Treat these as nops - the call will be handed as a regular get_by_id/op_call pair.

void JIT::emit_op_method_check(Instruction*) {}

void JIT::emitSlow_op_method_check(Instruction*, Vector<SlowCaseEntry>::iterator&) { ASSERT_NOT_REACHED(); }

#if ENABLE(JIT_OPTIMIZE_METHOD_CALLS)

#error "JIT_OPTIMIZE_METHOD_CALLS requires JIT_OPTIMIZE_PROPERTY_ACCESS"

#endif

void JIT::emit_op_get_by_id(Instruction* currentInstruction)

{

    unsigned resultVReg = currentInstruction[1].u.operand;

    unsigned baseVReg = currentInstruction[2].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));

    emitGetVirtualRegister(baseVReg, regT0);

    JITStubCall stubCall(this, cti_op_get_by_id_generic);

    stubCall.addArgument(regT0);

    stubCall.addArgument(ImmPtr(ident));

    stubCall.call(resultVReg);

    m_propertyAccessInstructionIndex++;

}

void JIT::emitSlow_op_get_by_id(Instruction*, Vector<SlowCaseEntry>::iterator&)

{

    ASSERT_NOT_REACHED();

}

void JIT::emit_op_put_by_id(Instruction* currentInstruction)

{

    unsigned baseVReg = currentInstruction[1].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[2].u.operand));

    unsigned valueVReg = currentInstruction[3].u.operand;

    unsigned direct = currentInstruction[8].u.operand;

    emitGetVirtualRegisters(baseVReg, regT0, valueVReg, regT1);

    JITStubCall stubCall(this, direct ? cti_op_put_by_id_direct_generic, cti_op_put_by_id_generic);

    stubCall.addArgument(regT0);

    stubCall.addArgument(ImmPtr(ident));

    stubCall.addArgument(regT1);

    stubCall.call();

    m_propertyAccessInstructionIndex++;

}

void JIT::emitSlow_op_put_by_id(Instruction*, Vector<SlowCaseEntry>::iterator&)

{

    ASSERT_NOT_REACHED();

}

#else // !ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)

/* ------------------------------ BEGIN: ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS) ------------------------------ */

#if ENABLE(JIT_OPTIMIZE_METHOD_CALLS)

void JIT::emit_op_method_check(Instruction* currentInstruction)

{

    // Assert that the following instruction is a get_by_id.

    ASSERT(m_interpreter->getOpcodeID((currentInstruction + OPCODE_LENGTH(op_method_check))->u.opcode) == op_get_by_id);

    currentInstruction += OPCODE_LENGTH(op_method_check);

    unsigned resultVReg = currentInstruction[1].u.operand;

    unsigned baseVReg = currentInstruction[2].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));

    emitGetVirtualRegister(baseVReg, regT0);

    // Do the method check - check the object & its prototype's structure inline (this is the common case).

    m_methodCallCompilationInfo.append(MethodCallCompilationInfo(m_propertyAccessInstructionIndex));

    MethodCallCompilationInfo& info = m_methodCallCompilationInfo.last();

    Jump notCell = emitJumpIfNotJSCell(regT0);

    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);

    Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), info.structureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

    DataLabelPtr protoStructureToCompare, protoObj = moveWithPatch(ImmPtr(0), regT1);

    Jump protoStructureCheck = branchPtrWithPatch(NotEqual, Address(regT1, OBJECT_OFFSETOF(JSCell, m_structure)), protoStructureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

    // This will be relinked to load the function without doing a load.

    DataLabelPtr putFunction = moveWithPatch(ImmPtr(0), regT0);

    END_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);

    Jump match = jump();

    ASSERT_JIT_OFFSET(differenceBetween(info.structureToCompare, protoObj), patchOffsetMethodCheckProtoObj);

    ASSERT_JIT_OFFSET(differenceBetween(info.structureToCompare, protoStructureToCompare), patchOffsetMethodCheckProtoStruct);

    ASSERT_JIT_OFFSET(differenceBetween(info.structureToCompare, putFunction), patchOffsetMethodCheckPutFunction);

    // Link the failure cases here.

    notCell.link(this);

    structureCheck.link(this);

    protoStructureCheck.link(this);

    // Do a regular(ish) get_by_id (the slow case will be link to

    // cti_op_get_by_id_method_check instead of cti_op_get_by_id.

    compileGetByIdHotPath(resultVReg, baseVReg, ident, m_propertyAccessInstructionIndex++);

    match.link(this);

    emitPutVirtualRegister(resultVReg);

    // We've already generated the following get_by_id, so make sure it's skipped over.

    m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);

}

void JIT::emitSlow_op_method_check(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)

{

    currentInstruction += OPCODE_LENGTH(op_method_check);

    unsigned resultVReg = currentInstruction[1].u.operand;

    unsigned baseVReg = currentInstruction[2].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));

    compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, true);

    // We've already generated the following get_by_id, so make sure it's skipped over.

    m_bytecodeOffset += OPCODE_LENGTH(op_get_by_id);

}

#else //!ENABLE(JIT_OPTIMIZE_METHOD_CALLS)

// Treat these as nops - the call will be handed as a regular get_by_id/op_call pair.

void JIT::emit_op_method_check(Instruction*) {}

void JIT::emitSlow_op_method_check(Instruction*, Vector<SlowCaseEntry>::iterator&) { ASSERT_NOT_REACHED(); }

#endif

void JIT::emit_op_get_by_id(Instruction* currentInstruction)

{

    unsigned resultVReg = currentInstruction[1].u.operand;

    unsigned baseVReg = currentInstruction[2].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));

    emitGetVirtualRegister(baseVReg, regT0);

    compileGetByIdHotPath(resultVReg, baseVReg, ident, m_propertyAccessInstructionIndex++);

    emitPutVirtualRegister(resultVReg);

}

void JIT::compileGetByIdHotPath(int, int baseVReg, Identifier*, unsigned propertyAccessInstructionIndex)

{

    // As for put_by_id, get_by_id requires the offset of the Structure and the offset of the access to be patched.

    // Additionally, for get_by_id we need patch the offset of the branch to the slow case (we patch this to jump

    // to array-length / prototype access tranpolines, and finally we also the the property-map access offset as a label

    // to jump back to if one of these trampolies finds a match.

    emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);

    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);

    Label hotPathBegin(this);

    m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].hotPathBegin = hotPathBegin;

    DataLabelPtr structureToCompare;

    Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), structureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

    addSlowCase(structureCheck);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureToCompare), patchOffsetGetByIdStructure);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureCheck), patchOffsetGetByIdBranchToSlowCase)

    Label externalLoad = loadPtrWithPatchToLEA(Address(regT0, OBJECT_OFFSETOF(JSObject, m_externalStorage)), regT0);

    Label externalLoadComplete(this);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, externalLoad), patchOffsetGetByIdExternalLoad);

    ASSERT_JIT_OFFSET(differenceBetween(externalLoad, externalLoadComplete), patchLengthGetByIdExternalLoad);

    DataLabel32 displacementLabel = loadPtrWithAddressOffsetPatch(Address(regT0, patchGetByIdDefaultOffset), regT0);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, displacementLabel), patchOffsetGetByIdPropertyMapOffset);

    Label putResult(this);

    END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdHotPath);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, putResult), patchOffsetGetByIdPutResult);

}

void JIT::emitSlow_op_get_by_id(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)

{

    unsigned resultVReg = currentInstruction[1].u.operand;

    unsigned baseVReg = currentInstruction[2].u.operand;

    Identifier* ident = &(m_codeBlock->identifier(currentInstruction[3].u.operand));

    compileGetByIdSlowCase(resultVReg, baseVReg, ident, iter, false);

}

void JIT::compileGetByIdSlowCase(int resultVReg, int baseVReg, Identifier* ident, Vector<SlowCaseEntry>::iterator& iter, bool isMethodCheck)

{

    // As for the hot path of get_by_id, above, we ensure that we can use an architecture specific offset

    // so that we only need track one pointer into the slow case code - we track a pointer to the location

    // of the call (which we can use to look up the patch information), but should a array-length or

    // prototype access trampoline fail we want to bail out back to here.  To do so we can subtract back

    // the distance from the call to the head of the slow case.

    linkSlowCaseIfNotJSCell(iter, baseVReg);

    linkSlowCase(iter);

    BEGIN_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);

#ifndef NDEBUG

    Label coldPathBegin(this);

#endif

    JITStubCall stubCall(this, isMethodCheck ? cti_op_get_by_id_method_check : cti_op_get_by_id);

    stubCall.addArgument(regT0);

    stubCall.addArgument(ImmPtr(ident));

    Call call = stubCall.call(resultVReg);

    END_UNINTERRUPTED_SEQUENCE(sequenceGetByIdSlowCase);

    ASSERT_JIT_OFFSET(differenceBetween(coldPathBegin, call), patchOffsetGetByIdSlowCaseCall);

    // Track the location of the call; this will be used to recover patch information.

    m_propertyAccessCompilationInfo[m_propertyAccessInstructionIndex].callReturnLocation = call;

    m_propertyAccessInstructionIndex++;

}

void JIT::emit_op_put_by_id(Instruction* currentInstruction)

{

    unsigned baseVReg = currentInstruction[1].u.operand;

    unsigned valueVReg = currentInstruction[3].u.operand;

    unsigned propertyAccessInstructionIndex = m_propertyAccessInstructionIndex++;

    // In order to be able to patch both the Structure, and the object offset, we store one pointer,

    // to just after the arguments have been loaded into registers 'hotPathBegin', and we generate code

    // such that the Structure & offset are always at the same distance from this.

    emitGetVirtualRegisters(baseVReg, regT0, valueVReg, regT1);

    // Jump to a slow case if either the base object is an immediate, or if the Structure does not match.

    emitJumpSlowCaseIfNotJSCell(regT0, baseVReg);

    BEGIN_UNINTERRUPTED_SEQUENCE(sequencePutById);

    Label hotPathBegin(this);

    m_propertyAccessCompilationInfo[propertyAccessInstructionIndex].hotPathBegin = hotPathBegin;

    // It is important that the following instruction plants a 32bit immediate, in order that it can be patched over.

    DataLabelPtr structureToCompare;

    addSlowCase(branchPtrWithPatch(NotEqual, Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), structureToCompare, ImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure))));

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureToCompare), patchOffsetPutByIdStructure);

    // Plant a load from a bogus ofset in the object's property map; we will patch this later, if it is to be used.

    Label externalLoad = loadPtrWithPatchToLEA(Address(regT0, OBJECT_OFFSETOF(JSObject, m_externalStorage)), regT0);

    Label externalLoadComplete(this);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, externalLoad), patchOffsetPutByIdExternalLoad);

    ASSERT_JIT_OFFSET(differenceBetween(externalLoad, externalLoadComplete), patchLengthPutByIdExternalLoad);

    DataLabel32 displacementLabel = storePtrWithAddressOffsetPatch(regT1, Address(regT0, patchGetByIdDefaultOffset));

    END_UNINTERRUPTED_SEQUENCE(sequencePutById);

    ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, displacementLabel), patchOffsetPutByIdPropertyMapOffset);

}