/*

* 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)

#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 {

#if USE(JSVALUE64)

JIT::CodeRef JIT::stringGetByValStubGenerator(JSGlobalData* globalData)

{

JSInterfaceJIT jit;

JumpList failures;

failures.append(jit.branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSString::s_info)));

// Load string length to regT2, 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);

failures.append(jit.branchTest32(Zero, 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

JumpList is16Bit;

JumpList cont8Bit;

// Load the string flags

jit.loadPtr(Address(regT0, ThunkHelpers::stringImplFlagsOffset()), regT2);

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

is16Bit.append(jit.branchTest32(Zero, regT2, TrustedImm32(ThunkHelpers::stringImpl8BitFlag())));

jit.load8(BaseIndex(regT0, regT1, TimesOne, 0), regT0);

cont8Bit.append(jit.jump());

is16Bit.link(&jit);

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

cont8Bit.link(&jit);

failures.append(jit.branch32(AboveOrEqual, regT0, TrustedImm32(0x100)));

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

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

jit.ret();

failures.link(&jit);

jit.move(TrustedImm32(0), regT0);

jit.ret();

LinkBuffer patchBuffer(*globalData, &jit, GLOBAL_THUNK_ID);

return patchBuffer.finalizeCode();

}

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);

// 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);

emitJumpSlowCaseIfNotJSCell(regT0, base);

addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info)));

loadPtr(Address(regT0, JSArray::storageOffset()), regT2);

addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));

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

addSlowCase(branchTestPtr(Zero, regT0));

emitValueProfilingSite();

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, JSCell::classInfoOffset()), TrustedImmPtr(&JSString::s_info));

emitNakedCall(CodeLocationLabel(m_globalData->getCTIStub(stringGetByValStubGenerator).code()));

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);

emitValueProfilingSite();

}

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

{

loadPtr(Address(base, JSObject::offsetOfPropertyStorage()), scratch);

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

}

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, JSCell::structureOffset()), regT2);

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

load32(addressFor(i), regT3);

sub32(TrustedImm32(1), regT3);

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

compileGetDirectOffset(regT0, regT0, 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);

// See comment in op_get_by_val.

zeroExtend32ToPtr(regT1, regT1);

emitJumpSlowCaseIfNotJSCell(regT0, base);

addSlowCase(branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info)));

addSlowCase(branch32(AboveOrEqual, regT1, Address(regT0, JSArray::vectorLengthOffset())));

loadPtr(Address(regT0, JSArray::storageOffset()), regT2);

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

Label storeResult(this);

emitGetVirtualRegister(value, regT3);

storePtr(regT3, BaseIndex(regT2, regT1, ScalePtr, OBJECT_OFFSETOF(ArrayStorage, m_vector[0])));

Jump end = jump();

empty.link(this);

add32(TrustedImm32(1), Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector)));

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

add32(TrustedImm32(1), regT1);

store32(regT1, Address(regT2, OBJECT_OFFSETOF(ArrayStorage, m_length)));

sub32(TrustedImm32(1), regT1);

jump().linkTo(storeResult, this);

end.link(this);

emitWriteBarrier(regT0, regT3, regT1, regT3, ShouldFilterImmediates, WriteBarrierForPropertyAccess);

}

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

{

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

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

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

linkSlowCase(iter); // property int32 check

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

linkSlowCase(iter); // base not array check

linkSlowCase(iter); // in vector check

JITStubCall stubPutByValCall(this, cti_op_put_by_val);

stubPutByValCall.addArgument(regT0);

stubPutByValCall.addArgument(property, regT2);

stubPutByValCall.addArgument(value, regT2);

stubPutByValCall.call();

}

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(TrustedImm32(currentInstruction[2].u.operand));

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

stubCall.call();

}

void JIT::emit_op_put_getter_setter(Instruction* currentInstruction)

{

JITStubCall stubCall(this, cti_op_put_getter_setter);

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

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

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

stubCall.addArgument(currentInstruction[4].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(TrustedImmPtr(&m_codeBlock->identifier(currentInstruction[3].u.operand)));

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

}

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_bytecodeOffset, m_propertyAccessCompilationInfo.size()));

MethodCallCompilationInfo& info = m_methodCallCompilationInfo.last();

Jump notCell = emitJumpIfNotJSCell(regT0);

BEGIN_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);

Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), info.structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

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

Jump protoStructureCheck = branchPtrWithPatch(NotEqual, Address(regT1, JSCell::structureOffset()), protoStructureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

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

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

END_UNINTERRUPTED_SEQUENCE(sequenceMethodCheck);

Jump match = jump();

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

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

ASSERT_JIT_OFFSET_UNUSED(putFunction, 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(baseVReg, ident);

match.link(this);

emitValueProfilingSite(m_bytecodeOffset + OPCODE_LENGTH(op_method_check));

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);

emitValueProfilingSite(m_bytecodeOffset + OPCODE_LENGTH(op_method_check));

// 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::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(baseVReg, ident);

emitValueProfilingSite();

emitPutVirtualRegister(resultVReg);

}

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

{

// 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.append(PropertyStubCompilationInfo());

m_propertyAccessCompilationInfo.last().bytecodeIndex = m_bytecodeOffset;

m_propertyAccessCompilationInfo.last().hotPathBegin = hotPathBegin;

DataLabelPtr structureToCompare;

Jump structureCheck = branchPtrWithPatch(NotEqual, Address(regT0, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure)));

addSlowCase(structureCheck);

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

ASSERT_JIT_OFFSET(differenceBetween(hotPathBegin, structureCheck), patchOffsetGetByIdBranchToSlowCase)

loadPtr(Address(regT0, JSObject::offsetOfPropertyStorage()), regT0);

DataLabelCompact displacementLabel = loadPtrWithCompactAddressOffsetPatch(Address(regT0, patchGetByIdDefaultOffset), regT0);

ASSERT_JIT_OFFSET_UNUSED(displacementLabel, 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);

emitValueProfilingSite();

}

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(TrustedImmPtr(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;

}

void JIT::emit_op_put_by_id(Instruction* currentInstruction)

{

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

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

// 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.append(PropertyStubCompilationInfo());

m_propertyAccessCompilationInfo.last().bytecodeIndex = m_bytecodeOffset;

m_propertyAccessCompilationInfo.last().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, JSCell::structureOffset()), structureToCompare, TrustedImmPtr(reinterpret_cast<void*>(patchGetByIdDefaultStructure))));

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

loadPtr(Address(regT0, JSObject::offsetOfPropertyStorage()), regT2);

DataLabel32 displacementLabel = storePtrWithAddressOffsetPatch(regT1, Address(regT2, patchPutByIdDefaultOffset));

END_UNINTERRUPTED_SEQUENCE(sequencePutById);

emitWriteBarrier(regT0, regT1, regT2, regT3, ShouldFilterImmediates, WriteBarrierForPropertyAccess);

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

}

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

{

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

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

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

linkSlowCaseIfNotJSCell(iter, baseVReg);

linkSlowCase(iter);

JITStubCall stubCall(this, direct ? cti_op_put_by_id_direct : cti_op_put_by_id);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(ident));

stubCall.addArgument(regT1);

Call call = stubCall.call();

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

m_propertyAccessCompilationInfo[m_propertyAccessInstructionIndex++].callReturnLocation = call;

}

// Compile a store into an object's property storage. May overwrite the

// value in objectReg.

void JIT::compilePutDirectOffset(RegisterID base, RegisterID value, size_t cachedOffset)

{

int offset = cachedOffset * sizeof(JSValue);

loadPtr(Address(base, JSObject::offsetOfPropertyStorage()), base);

storePtr(value, Address(base, offset));

}

// Compile a load from an object's property storage. May overwrite base.

void JIT::compileGetDirectOffset(RegisterID base, RegisterID result, size_t cachedOffset)

{

int offset = cachedOffset * sizeof(JSValue);

loadPtr(Address(base, JSObject::offsetOfPropertyStorage()), result);

loadPtr(Address(result, offset), result);

}

void JIT::compileGetDirectOffset(JSObject* base, RegisterID result, size_t cachedOffset)

{

loadPtr(base->addressOfPropertyStorage(), result);

loadPtr(Address(result, cachedOffset * sizeof(WriteBarrier<Unknown>)), result);

}

void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, size_t cachedOffset, StructureChain* chain, ReturnAddressPtr returnAddress, bool direct)

{

JumpList failureCases;

// Check eax is an object of the right Structure.

failureCases.append(emitJumpIfNotJSCell(regT0));

failureCases.append(branchPtr(NotEqual, Address(regT0, JSCell::structureOffset()), TrustedImmPtr(oldStructure)));

testPrototype(oldStructure->storedPrototype(), failureCases);

ASSERT(oldStructure->storedPrototype().isNull() || oldStructure->storedPrototype().asCell()->structure() == chain->head()->get());

// ecx = baseObject->m_structure

if (!direct) {

for (WriteBarrier<Structure>* it = chain->head(); *it; ++it) {

ASSERT((*it)->storedPrototype().isNull() || (*it)->storedPrototype().asCell()->structure() == it[1].get());

testPrototype((*it)->storedPrototype(), failureCases);

}

}

// If we succeed in all of our checks, and the code was optimizable, then make sure we

// decrement the rare case counter.

#if ENABLE(VALUE_PROFILER)

if (m_codeBlock->canCompileWithDFG()) {

sub32(

TrustedImm32(1),

AbsoluteAddress(&m_codeBlock->rareCaseProfileForBytecodeOffset(stubInfo->bytecodeIndex)->m_counter));

}

#endif

// emit a call only if storage realloc is needed

bool willNeedStorageRealloc = oldStructure->propertyStorageCapacity() != newStructure->propertyStorageCapacity();

if (willNeedStorageRealloc) {

// This trampoline was called to like a JIT stub; before we can can call again we need to

// remove the return address from the stack, to prevent the stack from becoming misaligned.

preserveReturnAddressAfterCall(regT3);

JITStubCall stubCall(this, cti_op_put_by_id_transition_realloc);

stubCall.skipArgument(); // base

stubCall.skipArgument(); // ident

stubCall.skipArgument(); // value

stubCall.addArgument(TrustedImm32(oldStructure->propertyStorageCapacity()));

stubCall.addArgument(TrustedImmPtr(newStructure));

stubCall.call(regT0);

emitGetJITStubArg(2, regT1);

restoreReturnAddressBeforeReturn(regT3);

}

// Planting the new structure triggers the write barrier so we need

// an unconditional barrier here.

emitWriteBarrier(regT0, regT1, regT2, regT3, UnconditionalWriteBarrier, WriteBarrierForPropertyAccess);

ASSERT(newStructure->classInfo() == oldStructure->classInfo());

storePtr(TrustedImmPtr(newStructure), Address(regT0, JSCell::structureOffset()));

compilePutDirectOffset(regT0, regT1, cachedOffset);

ret();

ASSERT(!failureCases.empty());

failureCases.link(this);

restoreArgumentReferenceForTrampoline();

Call failureCall = tailRecursiveCall();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

patchBuffer.link(failureCall, FunctionPtr(direct ? cti_op_put_by_id_direct_fail : cti_op_put_by_id_fail));

if (willNeedStorageRealloc) {

ASSERT(m_calls.size() == 1);

patchBuffer.link(m_calls[0].from, FunctionPtr(cti_op_put_by_id_transition_realloc));

}

stubInfo->stubRoutine = patchBuffer.finalizeCode();

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relinkCallerToTrampoline(returnAddress, CodeLocationLabel(stubInfo->stubRoutine.code()));

}

void JIT::patchGetByIdSelf(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, ReturnAddressPtr returnAddress)

{

RepatchBuffer repatchBuffer(codeBlock);

// We don't want to patch more than once - in future go to cti_op_get_by_id_generic.

// Should probably go to cti_op_get_by_id_fail, but that doesn't do anything interesting right now.

repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_self_fail));

int offset = sizeof(JSValue) * cachedOffset;

// Patch the offset into the propoerty map to load from, then patch the Structure to look for.

repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(patchOffsetGetByIdStructure), structure);

repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelCompactAtOffset(patchOffsetGetByIdPropertyMapOffset), offset);

}

void JIT::patchPutByIdReplace(CodeBlock* codeBlock, StructureStubInfo* stubInfo, Structure* structure, size_t cachedOffset, ReturnAddressPtr returnAddress, bool direct)

{

RepatchBuffer repatchBuffer(codeBlock);

// We don't want to patch more than once - in future go to cti_op_put_by_id_generic.

// Should probably go to cti_op_put_by_id_fail, but that doesn't do anything interesting right now.

repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(direct ? cti_op_put_by_id_direct_generic : cti_op_put_by_id_generic));

int offset = sizeof(JSValue) * cachedOffset;

// Patch the offset into the propoerty map to load from, then patch the Structure to look for.

repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabelPtrAtOffset(patchOffsetPutByIdStructure), structure);

repatchBuffer.repatch(stubInfo->hotPathBegin.dataLabel32AtOffset(patchOffsetPutByIdPropertyMapOffset), offset);

}

void JIT::privateCompilePatchGetArrayLength(ReturnAddressPtr returnAddress)

{

StructureStubInfo* stubInfo = &m_codeBlock->getStubInfo(returnAddress);

// Check eax is an array

Jump failureCases1 = branchPtr(NotEqual, Address(regT0, JSCell::classInfoOffset()), TrustedImmPtr(&JSArray::s_info));

// Checks out okay! - get the length from the storage

loadPtr(Address(regT0, JSArray::storageOffset()), regT3);

load32(Address(regT3, OBJECT_OFFSETOF(ArrayStorage, m_length)), regT2);

Jump failureCases2 = branch32(LessThan, regT2, TrustedImm32(0));

emitFastArithIntToImmNoCheck(regT2, regT0);

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

// Use the patch information to link the failure cases back to the original slow case routine.

CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);

patchBuffer.link(failureCases1, slowCaseBegin);

patchBuffer.link(failureCases2, slowCaseBegin);

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

// Track the stub we have created so that it will be deleted later.

stubInfo->stubRoutine = patchBuffer.finalizeCode();

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubInfo->stubRoutine.code()));

// We don't want to patch more than once - in future go to cti_op_put_by_id_generic.

repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_array_fail));

}

void JIT::privateCompileGetByIdProto(StructureStubInfo* stubInfo, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)

{

// The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is

// referencing the prototype object - let's speculatively load it's table nice and early!)

JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));

// Check eax is an object of the right Structure.

Jump failureCases1 = checkStructure(regT0, structure);

// Check the prototype object's Structure had not changed.

move(TrustedImmPtr(protoObject), regT3);

Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));

bool needsStubLink = false;

// Checks out okay!

if (slot.cachedPropertyType() == PropertySlot::Getter) {

needsStubLink = true;

compileGetDirectOffset(protoObject, regT1, cachedOffset);

JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);

stubCall.addArgument(regT1);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else if (slot.cachedPropertyType() == PropertySlot::Custom) {

needsStubLink = true;

JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);

stubCall.addArgument(TrustedImmPtr(protoObject));

stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));

stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else

compileGetDirectOffset(protoObject, regT0, cachedOffset);

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

// Use the patch information to link the failure cases back to the original slow case routine.

CodeLocationLabel slowCaseBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);

patchBuffer.link(failureCases1, slowCaseBegin);

patchBuffer.link(failureCases2, slowCaseBegin);

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

if (needsStubLink) {

for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {

if (iter->to)

patchBuffer.link(iter->from, FunctionPtr(iter->to));

}

}

// Track the stub we have created so that it will be deleted later.

stubInfo->stubRoutine = patchBuffer.finalizeCode();

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubInfo->stubRoutine.code()));

// We don't want to patch more than once - in future go to cti_op_put_by_id_generic.

repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));

}

void JIT::privateCompileGetByIdSelfList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* polymorphicStructures, int currentIndex, Structure* structure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset)

{

Jump failureCase = checkStructure(regT0, structure);

bool needsStubLink = false;

bool isDirect = false;

if (slot.cachedPropertyType() == PropertySlot::Getter) {

needsStubLink = true;

compileGetDirectOffset(regT0, regT1, cachedOffset);

JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);

stubCall.addArgument(regT1);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else if (slot.cachedPropertyType() == PropertySlot::Custom) {

needsStubLink = true;

JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));

stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else {

isDirect = true;

compileGetDirectOffset(regT0, regT0, cachedOffset);

}

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

if (needsStubLink) {

for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {

if (iter->to)

patchBuffer.link(iter->from, FunctionPtr(iter->to));

}

}

// Use the patch information to link the failure cases back to the original slow case routine.

CodeLocationLabel lastProtoBegin = CodeLocationLabel(polymorphicStructures->list[currentIndex - 1].stubRoutine.code());

if (!lastProtoBegin)

lastProtoBegin = stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall);

patchBuffer.link(failureCase, lastProtoBegin);

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

MacroAssemblerCodeRef stubCode = patchBuffer.finalizeCode();

polymorphicStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), stubCode, structure, isDirect);

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubCode.code()));

}

void JIT::privateCompileGetByIdProtoList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, Structure* prototypeStructure, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, CallFrame* callFrame)

{

// The prototype object definitely exists (if this stub exists the CodeBlock is referencing a Structure that is

// referencing the prototype object - let's speculatively load it's table nice and early!)

JSObject* protoObject = asObject(structure->prototypeForLookup(callFrame));

// Check eax is an object of the right Structure.

Jump failureCases1 = checkStructure(regT0, structure);

// Check the prototype object's Structure had not changed.

move(TrustedImmPtr(protoObject), regT3);

Jump failureCases2 = branchPtr(NotEqual, Address(regT3, JSCell::structureOffset()), TrustedImmPtr(prototypeStructure));

// Checks out okay!

bool needsStubLink = false;

bool isDirect = false;

if (slot.cachedPropertyType() == PropertySlot::Getter) {

needsStubLink = true;

compileGetDirectOffset(protoObject, regT1, cachedOffset);

JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);

stubCall.addArgument(regT1);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else if (slot.cachedPropertyType() == PropertySlot::Custom) {

needsStubLink = true;

JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);

stubCall.addArgument(TrustedImmPtr(protoObject));

stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));

stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else {

isDirect = true;

compileGetDirectOffset(protoObject, regT0, cachedOffset);

}

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

if (needsStubLink) {

for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {

if (iter->to)

patchBuffer.link(iter->from, FunctionPtr(iter->to));

}

}

// Use the patch information to link the failure cases back to the original slow case routine.

CodeLocationLabel lastProtoBegin = CodeLocationLabel(prototypeStructures->list[currentIndex - 1].stubRoutine.code());

patchBuffer.link(failureCases1, lastProtoBegin);

patchBuffer.link(failureCases2, lastProtoBegin);

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

MacroAssemblerCodeRef stubCode = patchBuffer.finalizeCode();

prototypeStructures->list[currentIndex].set(*m_globalData, m_codeBlock->ownerExecutable(), stubCode, structure, prototypeStructure, isDirect);

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubCode.code()));

}

void JIT::privateCompileGetByIdChainList(StructureStubInfo* stubInfo, PolymorphicAccessStructureList* prototypeStructures, int currentIndex, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, CallFrame* callFrame)

{

ASSERT(count);

JumpList bucketsOfFail;

// Check eax is an object of the right Structure.

Jump baseObjectCheck = checkStructure(regT0, structure);

bucketsOfFail.append(baseObjectCheck);

Structure* currStructure = structure;

WriteBarrier<Structure>* it = chain->head();

JSObject* protoObject = 0;

for (unsigned i = 0; i < count; ++i, ++it) {

protoObject = asObject(currStructure->prototypeForLookup(callFrame));

currStructure = it->get();

testPrototype(protoObject, bucketsOfFail);

}

ASSERT(protoObject);

bool needsStubLink = false;

bool isDirect = false;

if (slot.cachedPropertyType() == PropertySlot::Getter) {

needsStubLink = true;

compileGetDirectOffset(protoObject, regT1, cachedOffset);

JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);

stubCall.addArgument(regT1);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else if (slot.cachedPropertyType() == PropertySlot::Custom) {

needsStubLink = true;

JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);

stubCall.addArgument(TrustedImmPtr(protoObject));

stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));

stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else {

isDirect = true;

compileGetDirectOffset(protoObject, regT0, cachedOffset);

}

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

if (needsStubLink) {

for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {

if (iter->to)

patchBuffer.link(iter->from, FunctionPtr(iter->to));

}

}

// Use the patch information to link the failure cases back to the original slow case routine.

CodeLocationLabel lastProtoBegin = CodeLocationLabel(prototypeStructures->list[currentIndex - 1].stubRoutine.code());

patchBuffer.link(bucketsOfFail, lastProtoBegin);

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

CodeRef stubRoutine = patchBuffer.finalizeCode();

// Track the stub we have created so that it will be deleted later.

prototypeStructures->list[currentIndex].set(callFrame->globalData(), m_codeBlock->ownerExecutable(), stubRoutine, structure, chain, isDirect);

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubRoutine.code()));

}

void JIT::privateCompileGetByIdChain(StructureStubInfo* stubInfo, Structure* structure, StructureChain* chain, size_t count, const Identifier& ident, const PropertySlot& slot, size_t cachedOffset, ReturnAddressPtr returnAddress, CallFrame* callFrame)

{

ASSERT(count);

JumpList bucketsOfFail;

// Check eax is an object of the right Structure.

bucketsOfFail.append(checkStructure(regT0, structure));

Structure* currStructure = structure;

WriteBarrier<Structure>* it = chain->head();

JSObject* protoObject = 0;

for (unsigned i = 0; i < count; ++i, ++it) {

protoObject = asObject(currStructure->prototypeForLookup(callFrame));

currStructure = it->get();

testPrototype(protoObject, bucketsOfFail);

}

ASSERT(protoObject);

bool needsStubLink = false;

if (slot.cachedPropertyType() == PropertySlot::Getter) {

needsStubLink = true;

compileGetDirectOffset(protoObject, regT1, cachedOffset);

JITStubCall stubCall(this, cti_op_get_by_id_getter_stub);

stubCall.addArgument(regT1);

stubCall.addArgument(regT0);

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else if (slot.cachedPropertyType() == PropertySlot::Custom) {

needsStubLink = true;

JITStubCall stubCall(this, cti_op_get_by_id_custom_stub);

stubCall.addArgument(TrustedImmPtr(protoObject));

stubCall.addArgument(TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()));

stubCall.addArgument(TrustedImmPtr(const_cast<Identifier*>(&ident)));

stubCall.addArgument(TrustedImmPtr(stubInfo->callReturnLocation.executableAddress()));

stubCall.call();

} else

compileGetDirectOffset(protoObject, regT0, cachedOffset);

Jump success = jump();

LinkBuffer patchBuffer(*m_globalData, this, m_codeBlock);

if (needsStubLink) {

for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {

if (iter->to)

patchBuffer.link(iter->from, FunctionPtr(iter->to));

}

}

// Use the patch information to link the failure cases back to the original slow case routine.

patchBuffer.link(bucketsOfFail, stubInfo->callReturnLocation.labelAtOffset(-patchOffsetGetByIdSlowCaseCall));

// On success return back to the hot patch code, at a point it will perform the store to dest for us.

patchBuffer.link(success, stubInfo->hotPathBegin.labelAtOffset(patchOffsetGetByIdPutResult));

// Track the stub we have created so that it will be deleted later.

CodeRef stubRoutine = patchBuffer.finalizeCode();

stubInfo->stubRoutine = stubRoutine;

// Finally patch the jump to slow case back in the hot path to jump here instead.

CodeLocationJump jumpLocation = stubInfo->hotPathBegin.jumpAtOffset(patchOffsetGetByIdBranchToSlowCase);

RepatchBuffer repatchBuffer(m_codeBlock);

repatchBuffer.relink(jumpLocation, CodeLocationLabel(stubRoutine.code()));

// We don't want to patch more than once - in future go to cti_op_put_by_id_generic.

repatchBuffer.relinkCallerToFunction(returnAddress, FunctionPtr(cti_op_get_by_id_proto_list));

}

void JIT::emit_op_get_scoped_var(Instruction* currentInstruction)

{

int skip = currentInstruction[3].u.operand;

emitGetFromCallFrameHeaderPtr(RegisterFile::ScopeChain, regT0);

bool checkTopLevel = m_codeBlock->codeType() == FunctionCode && m_codeBlock->needsFullScopeChain();

ASSERT(skip || !checkTopLevel);

if (checkTopLevel && skip--) {

Jump activationNotCreated;

if (checkTopLevel)

activationNotCreated = branchTestPtr(Zero, addressFor(m_codeBlock->activationRegister()));

loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, next)), regT0);

activationNotCreated.link(this);

}

while (skip--)

loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, next)), regT0);

loadPtr(Address(regT0, OBJECT_OFFSETOF(ScopeChainNode, object)), regT0);

loadPtr(Address(regT0, JSVariableObject::offsetOfRegisters()), regT0);

loadPtr(Address(regT0, currentInstruction[2].u.operand * sizeof(Register)), regT0);

emitValueProfilingSite();

emitPutVirtualRegister(currentInstruction[1].u.operand);

}