JITOpcodes32_64.cpp   [plain text]

/*
 * Copyright (C) 2009-2018 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
 *
 * 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 "BytecodeStructs.h"
#include "CCallHelpers.h"
#include "Exception.h"
#include "JITInlines.h"
#include "JSArray.h"
#include "JSCell.h"
#include "JSFunction.h"
#include "JSPropertyNameEnumerator.h"
#include "LinkBuffer.h"
#include "MaxFrameExtentForSlowPathCall.h"
#include "Opcode.h"
#include "SlowPathCall.h"
#include "TypeProfilerLog.h"
#include "VirtualRegister.h"

namespace JSC {

void JIT::emit_op_mov(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;
    
    if (m_codeBlock->isConstantRegisterIndex(src))
        emitStore(dst, getConstantOperand(src));
    else {
        emitLoad(src, regT1, regT0);
        emitStore(dst, regT1, regT0);
    }
}

void JIT::emit_op_end(Instruction* currentInstruction)
{
    ASSERT(returnValueGPR != callFrameRegister);
    emitLoad(currentInstruction[1].u.operand, regT1, returnValueGPR);
    emitRestoreCalleeSaves();
    emitFunctionEpilogue();
    ret();
}

void JIT::emit_op_jmp(Instruction* currentInstruction)
{
    unsigned target = currentInstruction[1].u.operand;
    addJump(jump(), target);
}

void JIT::emit_op_new_object(Instruction* currentInstruction)
{
    Structure* structure = currentInstruction[3].u.objectAllocationProfile->structure();
    size_t allocationSize = JSFinalObject::allocationSize(structure->inlineCapacity());
    Allocator allocator = subspaceFor<JSFinalObject>(*m_vm)->allocatorForNonVirtual(allocationSize, AllocatorForMode::AllocatorIfExists);

    RegisterID resultReg = returnValueGPR;
    RegisterID allocatorReg = regT1;
    RegisterID scratchReg = regT3;

    if (!allocator)
        addSlowCase(jump());
    else {
        JumpList slowCases;
        auto butterfly = TrustedImmPtr(nullptr);
        auto mask = TrustedImm32(0);
        emitAllocateJSObject(resultReg, JITAllocator::constant(allocator), allocatorReg, TrustedImmPtr(structure), butterfly, mask, scratchReg, slowCases);
        emitInitializeInlineStorage(resultReg, structure->inlineCapacity());
        addSlowCase(slowCases);
        emitStoreCell(currentInstruction[1].u.operand, resultReg);
    }
}

void JIT::emitSlow_op_new_object(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    linkAllSlowCases(iter);

    int dst = currentInstruction[1].u.operand;
    Structure* structure = currentInstruction[3].u.objectAllocationProfile->structure();
    callOperation(operationNewObject, structure);
    emitStoreCell(dst, returnValueGPR);
}

void JIT::emit_op_overrides_has_instance(Instruction* currentInstruction)
{
    auto& bytecode = *reinterpret_cast<OpOverridesHasInstance*>(currentInstruction);
    int dst = bytecode.dst();
    int constructor = bytecode.constructor();
    int hasInstanceValue = bytecode.hasInstanceValue();

    emitLoadPayload(hasInstanceValue, regT0);
    // We don't jump if we know what Symbol.hasInstance would do.
    Jump hasInstanceValueNotCell = emitJumpIfNotJSCell(hasInstanceValue);
    Jump customhasInstanceValue = branchPtr(NotEqual, regT0, TrustedImmPtr(m_codeBlock->globalObject()->functionProtoHasInstanceSymbolFunction()));

    // We know that constructor is an object from the way bytecode is emitted for instanceof expressions.
    emitLoadPayload(constructor, regT0);

    // Check that constructor 'ImplementsDefaultHasInstance' i.e. the object is not a C-API user nor a bound function.
    test8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(ImplementsDefaultHasInstance), regT0);
    Jump done = jump();

    hasInstanceValueNotCell.link(this);
    customhasInstanceValue.link(this);
    move(TrustedImm32(1), regT0);

    done.link(this);
    emitStoreBool(dst, regT0);

}

void JIT::emit_op_instanceof(Instruction* currentInstruction)
{
    auto& bytecode = *reinterpret_cast<OpInstanceof*>(currentInstruction);
    int dst = bytecode.dst();
    int value = bytecode.value();
    int proto = bytecode.prototype();

    // Load the operands into registers.
    // We use regT0 for baseVal since we will be done with this first, and we can then use it for the result.
    emitLoadPayload(value, regT2);
    emitLoadPayload(proto, regT1);

    // Check that proto are cells. baseVal must be a cell - this is checked by the get_by_id for Symbol.hasInstance.
    emitJumpSlowCaseIfNotJSCell(value);
    emitJumpSlowCaseIfNotJSCell(proto);
    
    // Check that prototype is an object
    addSlowCase(emitJumpIfCellNotObject(regT1));

    // Optimistically load the result true, and start looping.
    // Initially, regT1 still contains proto and regT2 still contains value.
    // As we loop regT2 will be updated with its prototype, recursively walking the prototype chain.
    move(TrustedImm32(1), regT0);
    Label loop(this);

    addSlowCase(branch8(Equal, Address(regT2, JSCell::typeInfoTypeOffset()), TrustedImm32(ProxyObjectType)));

    // Load the prototype of the cell in regT2.  If this is equal to regT1 - WIN!
    // Otherwise, check if we've hit null - if we have then drop out of the loop, if not go again.
    loadPtr(Address(regT2, JSCell::structureIDOffset()), regT4);
    load32(Address(regT4, Structure::prototypeOffset() + TagOffset), regT3);
    load32(Address(regT4, Structure::prototypeOffset() + PayloadOffset), regT4);
    auto hasMonoProto = branch32(NotEqual, regT3, TrustedImm32(JSValue::EmptyValueTag));
    load32(Address(regT2, offsetRelativeToBase(knownPolyProtoOffset) + PayloadOffset), regT4);
    hasMonoProto.link(this);
    move(regT4, regT2);
    Jump isInstance = branchPtr(Equal, regT2, regT1);
    branchTest32(NonZero, regT2).linkTo(loop, this);

    // We get here either by dropping out of the loop, or if value was not an Object.  Result is false.
    move(TrustedImm32(0), regT0);

    // isInstance jumps right down to here, to skip setting the result to false (it has already set true).
    isInstance.link(this);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_instanceof_custom(Instruction*)
{
    // This always goes to slow path since we expect it to be rare.
    addSlowCase(jump());
}

void JIT::emitSlow_op_instanceof(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    linkAllSlowCases(iter);

    auto& bytecode = *reinterpret_cast<OpInstanceof*>(currentInstruction);
    int dst = bytecode.dst();
    int value = bytecode.value();
    int proto = bytecode.prototype();

    emitLoad(value, regT1, regT0);
    emitLoad(proto, regT3, regT2);
    callOperation(operationInstanceOf, dst, regT1, regT0, regT3, regT2);
}

void JIT::emitSlow_op_instanceof_custom(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    linkAllSlowCases(iter);

    auto& bytecode = *reinterpret_cast<OpInstanceofCustom*>(currentInstruction);
    int dst = bytecode.dst();
    int value = bytecode.value();
    int constructor = bytecode.constructor();
    int hasInstanceValue = bytecode.hasInstanceValue();

    emitLoad(value, regT1, regT0);
    emitLoadPayload(constructor, regT2);
    emitLoad(hasInstanceValue, regT4, regT3);
    callOperation(operationInstanceOfCustom, regT1, regT0, regT2, regT4, regT3);
    emitStoreBool(dst, returnValueGPR);
}
    
void JIT::emit_op_is_empty(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;
    
    emitLoad(value, regT1, regT0);
    compare32(Equal, regT1, TrustedImm32(JSValue::EmptyValueTag), regT0);

    emitStoreBool(dst, regT0);
}

void JIT::emit_op_is_undefined(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;
    
    emitLoad(value, regT1, regT0);
    Jump isCell = branch32(Equal, regT1, TrustedImm32(JSValue::CellTag));

    compare32(Equal, regT1, TrustedImm32(JSValue::UndefinedTag), regT0);
    Jump done = jump();
    
    isCell.link(this);
    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
    move(TrustedImm32(0), regT0);
    Jump notMasqueradesAsUndefined = jump();
    
    isMasqueradesAsUndefined.link(this);
    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT1);
    move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
    loadPtr(Address(regT1, Structure::globalObjectOffset()), regT1);
    compare32(Equal, regT0, regT1, regT0);

    notMasqueradesAsUndefined.link(this);
    done.link(this);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_is_boolean(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;
    
    emitLoadTag(value, regT0);
    compare32(Equal, regT0, TrustedImm32(JSValue::BooleanTag), regT0);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_is_number(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;
    
    emitLoadTag(value, regT0);
    add32(TrustedImm32(1), regT0);
    compare32(Below, regT0, TrustedImm32(JSValue::LowestTag + 1), regT0);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_is_cell_with_type(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;
    int type = currentInstruction[3].u.operand;

    emitLoad(value, regT1, regT0);
    Jump isNotCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    compare8(Equal, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(type), regT0);
    Jump done = jump();

    isNotCell.link(this);
    move(TrustedImm32(0), regT0);

    done.link(this);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_is_object(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int value = currentInstruction[2].u.operand;

    emitLoad(value, regT1, regT0);
    Jump isNotCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    compare8(AboveOrEqual, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(ObjectType), regT0);
    Jump done = jump();

    isNotCell.link(this);
    move(TrustedImm32(0), regT0);

    done.link(this);
    emitStoreBool(dst, regT0);
}

void JIT::emit_op_to_primitive(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    Jump isImm = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
    addSlowCase(emitJumpIfCellObject(regT0));
    isImm.link(this);

    if (dst != src)
        emitStore(dst, regT1, regT0);
}

void JIT::emit_op_set_function_name(Instruction* currentInstruction)
{
    int func = currentInstruction[1].u.operand;
    int name = currentInstruction[2].u.operand;
    emitLoadPayload(func, regT1);
    emitLoad(name, regT3, regT2);
    callOperation(operationSetFunctionName, regT1, regT3, regT2);
}

void JIT::emit_op_not(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoadTag(src, regT0);

    emitLoad(src, regT1, regT0);
    addSlowCase(branch32(NotEqual, regT1, TrustedImm32(JSValue::BooleanTag)));
    xor32(TrustedImm32(1), regT0);

    emitStoreBool(dst, regT0, (dst == src));
}

void JIT::emit_op_jfalse(Instruction* currentInstruction)
{
    int cond = currentInstruction[1].u.operand;
    unsigned target = currentInstruction[2].u.operand;

    emitLoad(cond, regT1, regT0);

    JSValueRegs value(regT1, regT0);
    GPRReg scratch = regT2;
    GPRReg result = regT3;
    bool shouldCheckMasqueradesAsUndefined = true;
    emitConvertValueToBoolean(*vm(), value, result, scratch, fpRegT0, fpRegT1, shouldCheckMasqueradesAsUndefined, m_codeBlock->globalObject());

    addJump(branchTest32(Zero, result), target);
}

void JIT::emit_op_jtrue(Instruction* currentInstruction)
{
    int cond = currentInstruction[1].u.operand;
    unsigned target = currentInstruction[2].u.operand;

    emitLoad(cond, regT1, regT0);
    bool shouldCheckMasqueradesAsUndefined = true;
    JSValueRegs value(regT1, regT0);
    GPRReg scratch = regT2;
    GPRReg result = regT3;
    emitConvertValueToBoolean(*vm(), value, result, scratch, fpRegT0, fpRegT1, shouldCheckMasqueradesAsUndefined, m_codeBlock->globalObject());

    addJump(branchTest32(NonZero, result), target);
}

void JIT::emit_op_jeq_null(Instruction* currentInstruction)
{
    int src = currentInstruction[1].u.operand;
    unsigned target = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    Jump isNotMasqueradesAsUndefined = branchTest8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
    move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
    addJump(branchPtr(Equal, Address(regT2, Structure::globalObjectOffset()), regT0), target);
    Jump masqueradesGlobalObjectIsForeign = jump();

    // Now handle the immediate cases - undefined & null
    isImmediate.link(this);
    ASSERT((JSValue::UndefinedTag + 1 == JSValue::NullTag) && (JSValue::NullTag & 0x1));
    or32(TrustedImm32(1), regT1);
    addJump(branch32(Equal, regT1, TrustedImm32(JSValue::NullTag)), target);

    isNotMasqueradesAsUndefined.link(this);
    masqueradesGlobalObjectIsForeign.link(this);
}

void JIT::emit_op_jneq_null(Instruction* currentInstruction)
{
    int src = currentInstruction[1].u.operand;
    unsigned target = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    addJump(branchTest8(Zero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined)), target);
    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
    move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
    addJump(branchPtr(NotEqual, Address(regT2, Structure::globalObjectOffset()), regT0), target);
    Jump wasNotImmediate = jump();

    // Now handle the immediate cases - undefined & null
    isImmediate.link(this);

    ASSERT((JSValue::UndefinedTag + 1 == JSValue::NullTag) && (JSValue::NullTag & 0x1));
    or32(TrustedImm32(1), regT1);
    addJump(branch32(NotEqual, regT1, TrustedImm32(JSValue::NullTag)), target);

    wasNotImmediate.link(this);
}

void JIT::emit_op_jneq_ptr(Instruction* currentInstruction)
{
    int src = currentInstruction[1].u.operand;
    Special::Pointer ptr = currentInstruction[2].u.specialPointer;
    unsigned target = currentInstruction[3].u.operand;

    emitLoad(src, regT1, regT0);
    CCallHelpers::Jump notCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
    CCallHelpers::Jump equal = branchPtr(Equal, regT0, TrustedImmPtr(actualPointerFor(m_codeBlock, ptr)));
    notCell.link(this);
    store32(TrustedImm32(1), &currentInstruction[4].u.operand);
    addJump(jump(), target);
    equal.link(this);
}

void JIT::emit_op_eq(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src1 = currentInstruction[2].u.operand;
    int src2 = currentInstruction[3].u.operand;

    emitLoad2(src1, regT1, regT0, src2, regT3, regT2);
    addSlowCase(branch32(NotEqual, regT1, regT3));
    addSlowCase(branch32(Equal, regT1, TrustedImm32(JSValue::CellTag)));
    addSlowCase(branch32(Below, regT1, TrustedImm32(JSValue::LowestTag)));

    compare32(Equal, regT0, regT2, regT0);

    emitStoreBool(dst, regT0);
}

void JIT::emitSlow_op_eq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    int dst = currentInstruction[1].u.operand;
    int op1 = currentInstruction[2].u.operand;
    int op2 = currentInstruction[3].u.operand;

    JumpList storeResult;
    JumpList genericCase;

    genericCase.append(getSlowCase(iter)); // tags not equal

    linkSlowCase(iter); // tags equal and JSCell
    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));

    // String case.
    callOperation(operationCompareStringEq, regT0, regT2);
    storeResult.append(jump());

    // Generic case.
    genericCase.append(getSlowCase(iter)); // doubles
    genericCase.link(this);
    emitLoad(op1, regT1, regT0);
    emitLoad(op2, regT3, regT2);
    callOperation(operationCompareEq, regT1, regT0, regT3, regT2);

    storeResult.link(this);
    emitStoreBool(dst, returnValueGPR);
}

void JIT::emit_op_neq(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src1 = currentInstruction[2].u.operand;
    int src2 = currentInstruction[3].u.operand;

    emitLoad2(src1, regT1, regT0, src2, regT3, regT2);
    addSlowCase(branch32(NotEqual, regT1, regT3));
    addSlowCase(branch32(Equal, regT1, TrustedImm32(JSValue::CellTag)));
    addSlowCase(branch32(Below, regT1, TrustedImm32(JSValue::LowestTag)));

    compare32(NotEqual, regT0, regT2, regT0);

    emitStoreBool(dst, regT0);
}

void JIT::emitSlow_op_neq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    int dst = currentInstruction[1].u.operand;

    JumpList storeResult;
    JumpList genericCase;

    genericCase.append(getSlowCase(iter)); // tags not equal

    linkSlowCase(iter); // tags equal and JSCell
    genericCase.append(branchPtr(NotEqual, Address(regT0, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));
    genericCase.append(branchPtr(NotEqual, Address(regT2, JSCell::structureIDOffset()), TrustedImmPtr(m_vm->stringStructure.get())));

    // String case.
    callOperation(operationCompareStringEq, regT0, regT2);
    storeResult.append(jump());

    // Generic case.
    genericCase.append(getSlowCase(iter)); // doubles
    genericCase.link(this);
    callOperation(operationCompareEq, regT1, regT0, regT3, regT2);

    storeResult.link(this);
    xor32(TrustedImm32(0x1), returnValueGPR);
    emitStoreBool(dst, returnValueGPR);
}

void JIT::compileOpStrictEq(Instruction* currentInstruction, CompileOpStrictEqType type)
{
    int dst = currentInstruction[1].u.operand;
    int src1 = currentInstruction[2].u.operand;
    int src2 = currentInstruction[3].u.operand;

    emitLoad2(src1, regT1, regT0, src2, regT3, regT2);

    // Bail if the tags differ, or are double.
    addSlowCase(branch32(NotEqual, regT1, regT3));
    addSlowCase(branch32(Below, regT1, TrustedImm32(JSValue::LowestTag)));

    // Jump to a slow case if both are strings or symbols (non object).
    Jump notCell = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));
    Jump firstIsObject = emitJumpIfCellObject(regT0);
    addSlowCase(emitJumpIfCellNotObject(regT2));
    notCell.link(this);
    firstIsObject.link(this);

    // Simply compare the payloads.
    if (type == OpStrictEq)
        compare32(Equal, regT0, regT2, regT0);
    else
        compare32(NotEqual, regT0, regT2, regT0);

    emitStoreBool(dst, regT0);
}

void JIT::emit_op_stricteq(Instruction* currentInstruction)
{
    compileOpStrictEq(currentInstruction, OpStrictEq);
}

void JIT::emit_op_nstricteq(Instruction* currentInstruction)
{
    compileOpStrictEq(currentInstruction, OpNStrictEq);
}

void JIT::emit_op_eq_null(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);
    Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
    move(TrustedImm32(0), regT1);
    Jump wasNotMasqueradesAsUndefined = jump();

    isMasqueradesAsUndefined.link(this);
    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
    move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
    loadPtr(Address(regT2, Structure::globalObjectOffset()), regT2);
    compare32(Equal, regT0, regT2, regT1);
    Jump wasNotImmediate = jump();

    isImmediate.link(this);

    compare32(Equal, regT1, TrustedImm32(JSValue::NullTag), regT2);
    compare32(Equal, regT1, TrustedImm32(JSValue::UndefinedTag), regT1);
    or32(regT2, regT1);

    wasNotImmediate.link(this);
    wasNotMasqueradesAsUndefined.link(this);

    emitStoreBool(dst, regT1);
}

void JIT::emit_op_neq_null(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);
    Jump isImmediate = branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag));

    Jump isMasqueradesAsUndefined = branchTest8(NonZero, Address(regT0, JSCell::typeInfoFlagsOffset()), TrustedImm32(MasqueradesAsUndefined));
    move(TrustedImm32(1), regT1);
    Jump wasNotMasqueradesAsUndefined = jump();

    isMasqueradesAsUndefined.link(this);
    loadPtr(Address(regT0, JSCell::structureIDOffset()), regT2);
    move(TrustedImmPtr(m_codeBlock->globalObject()), regT0);
    loadPtr(Address(regT2, Structure::globalObjectOffset()), regT2);
    compare32(NotEqual, regT0, regT2, regT1);
    Jump wasNotImmediate = jump();

    isImmediate.link(this);

    compare32(NotEqual, regT1, TrustedImm32(JSValue::NullTag), regT2);
    compare32(NotEqual, regT1, TrustedImm32(JSValue::UndefinedTag), regT1);
    and32(regT2, regT1);

    wasNotImmediate.link(this);
    wasNotMasqueradesAsUndefined.link(this);

    emitStoreBool(dst, regT1);
}

void JIT::emit_op_throw(Instruction* currentInstruction)
{
    ASSERT(regT0 == returnValueGPR);
    copyCalleeSavesToEntryFrameCalleeSavesBuffer(vm()->topEntryFrame);
    emitLoad(currentInstruction[1].u.operand, regT1, regT0);
    callOperationNoExceptionCheck(operationThrow, regT1, regT0);
    jumpToExceptionHandler(*vm());
}

void JIT::emit_op_to_number(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    Jump isInt32 = branch32(Equal, regT1, TrustedImm32(JSValue::Int32Tag));
    addSlowCase(branch32(AboveOrEqual, regT1, TrustedImm32(JSValue::LowestTag)));
    isInt32.link(this);

    emitValueProfilingSite();
    if (src != dst)
        emitStore(dst, regT1, regT0);
}

void JIT::emit_op_to_string(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    addSlowCase(branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag)));
    addSlowCase(branch8(NotEqual, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType)));

    if (src != dst)
        emitStore(dst, regT1, regT0);
}

void JIT::emit_op_to_object(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int src = currentInstruction[2].u.operand;

    emitLoad(src, regT1, regT0);

    addSlowCase(branch32(NotEqual, regT1, TrustedImm32(JSValue::CellTag)));
    addSlowCase(branch8(Below, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(ObjectType)));

    emitValueProfilingSite();
    if (src != dst)
        emitStore(dst, regT1, regT0);
}

void JIT::emit_op_catch(Instruction* currentInstruction)
{
    restoreCalleeSavesFromEntryFrameCalleeSavesBuffer(vm()->topEntryFrame);

    move(TrustedImmPtr(m_vm), regT3);
    // operationThrow returns the callFrame for the handler.
    load32(Address(regT3, VM::callFrameForCatchOffset()), callFrameRegister);
    storePtr(TrustedImmPtr(nullptr), Address(regT3, VM::callFrameForCatchOffset()));

    addPtr(TrustedImm32(stackPointerOffsetFor(codeBlock()) * sizeof(Register)), callFrameRegister, stackPointerRegister);

    callOperationNoExceptionCheck(operationCheckIfExceptionIsUncatchableAndNotifyProfiler);
    Jump isCatchableException = branchTest32(Zero, returnValueGPR);
    jumpToExceptionHandler(*vm());
    isCatchableException.link(this);

    move(TrustedImmPtr(m_vm), regT3);

    // Now store the exception returned by operationThrow.
    load32(Address(regT3, VM::exceptionOffset()), regT2);
    move(TrustedImm32(JSValue::CellTag), regT1);

    store32(TrustedImm32(0), Address(regT3, VM::exceptionOffset()));

    unsigned exception = currentInstruction[1].u.operand;
    emitStore(exception, regT1, regT2);

    load32(Address(regT2, Exception::valueOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
    load32(Address(regT2, Exception::valueOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);

    unsigned thrownValue = currentInstruction[2].u.operand;
    emitStore(thrownValue, regT1, regT0);

#if ENABLE(DFG_JIT)
    // FIXME: consider inline caching the process of doing OSR entry, including
    // argument type proofs, storing locals to the buffer, etc
    // https://bugs.webkit.org/show_bug.cgi?id=175598

    ValueProfileAndOperandBuffer* buffer = static_cast<ValueProfileAndOperandBuffer*>(currentInstruction[3].u.pointer);
    if (buffer || !shouldEmitProfiling())
        callOperation(operationTryOSREnterAtCatch, m_bytecodeOffset);
    else
        callOperation(operationTryOSREnterAtCatchAndValueProfile, m_bytecodeOffset);
    auto skipOSREntry = branchTestPtr(Zero, returnValueGPR);
    emitRestoreCalleeSaves();
    jump(returnValueGPR);
    skipOSREntry.link(this);
    if (buffer && shouldEmitProfiling()) {
        buffer->forEach([&] (ValueProfileAndOperand& profile) {
            JSValueRegs regs(regT1, regT0);
            emitGetVirtualRegister(profile.m_operand, regs);
            emitValueProfilingSite(profile.m_profile);
        });
    }
#endif // ENABLE(DFG_JIT)
}

void JIT::emit_op_identity_with_profile(Instruction*)
{
    // We don't need to do anything here...
}

void JIT::emit_op_get_parent_scope(Instruction* currentInstruction)
{
    int currentScope = currentInstruction[2].u.operand;
    emitLoadPayload(currentScope, regT0);
    loadPtr(Address(regT0, JSScope::offsetOfNext()), regT0);
    emitStoreCell(currentInstruction[1].u.operand, regT0);
}

void JIT::emit_op_switch_imm(Instruction* currentInstruction)
{
    size_t tableIndex = currentInstruction[1].u.operand;
    unsigned defaultOffset = currentInstruction[2].u.operand;
    unsigned scrutinee = currentInstruction[3].u.operand;

    // create jump table for switch destinations, track this switch statement.
    SimpleJumpTable* jumpTable = &m_codeBlock->switchJumpTable(tableIndex);
    m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset, SwitchRecord::Immediate));
    jumpTable->ensureCTITable();

    emitLoad(scrutinee, regT1, regT0);
    callOperation(operationSwitchImmWithUnknownKeyType, regT1, regT0, tableIndex);
    jump(returnValueGPR);
}

void JIT::emit_op_switch_char(Instruction* currentInstruction)
{
    size_t tableIndex = currentInstruction[1].u.operand;
    unsigned defaultOffset = currentInstruction[2].u.operand;
    unsigned scrutinee = currentInstruction[3].u.operand;

    // create jump table for switch destinations, track this switch statement.
    SimpleJumpTable* jumpTable = &m_codeBlock->switchJumpTable(tableIndex);
    m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset, SwitchRecord::Character));
    jumpTable->ensureCTITable();

    emitLoad(scrutinee, regT1, regT0);
    callOperation(operationSwitchCharWithUnknownKeyType, regT1, regT0, tableIndex);
    jump(returnValueGPR);
}

void JIT::emit_op_switch_string(Instruction* currentInstruction)
{
    size_t tableIndex = currentInstruction[1].u.operand;
    unsigned defaultOffset = currentInstruction[2].u.operand;
    unsigned scrutinee = currentInstruction[3].u.operand;

    // create jump table for switch destinations, track this switch statement.
    StringJumpTable* jumpTable = &m_codeBlock->stringSwitchJumpTable(tableIndex);
    m_switches.append(SwitchRecord(jumpTable, m_bytecodeOffset, defaultOffset));

    emitLoad(scrutinee, regT1, regT0);
    callOperation(operationSwitchStringWithUnknownKeyType, regT1, regT0, tableIndex);
    jump(returnValueGPR);
}

void JIT::emit_op_debug(Instruction* currentInstruction)
{
    load32(codeBlock()->debuggerRequestsAddress(), regT0);
    Jump noDebuggerRequests = branchTest32(Zero, regT0);
    callOperation(operationDebug, currentInstruction[1].u.operand);
    noDebuggerRequests.link(this);
}


void JIT::emit_op_enter(Instruction* currentInstruction)
{
    emitEnterOptimizationCheck();
    
    // Even though JIT code doesn't use them, we initialize our constant
    // registers to zap stale pointers, to avoid unnecessarily prolonging
    // object lifetime and increasing GC pressure.
    for (int i = 0; i < m_codeBlock->m_numVars; ++i)
        emitStore(virtualRegisterForLocal(i).offset(), jsUndefined());

    JITSlowPathCall slowPathCall(this, currentInstruction, slow_path_enter);
    slowPathCall.call();
}

void JIT::emit_op_get_scope(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    emitGetFromCallFrameHeaderPtr(CallFrameSlot::callee, regT0);
    loadPtr(Address(regT0, JSFunction::offsetOfScopeChain()), regT0);
    emitStoreCell(dst, regT0);
}

void JIT::emit_op_create_this(Instruction* currentInstruction)
{
    int callee = currentInstruction[2].u.operand;
    WriteBarrierBase<JSCell>* cachedFunction = &currentInstruction[4].u.jsCell;
    RegisterID calleeReg = regT0;
    RegisterID rareDataReg = regT4;
    RegisterID resultReg = regT0;
    RegisterID allocatorReg = regT1;
    RegisterID structureReg = regT2;
    RegisterID cachedFunctionReg = regT4;
    RegisterID scratchReg = regT3;

    emitLoadPayload(callee, calleeReg);
    addSlowCase(branch8(NotEqual, Address(calleeReg, JSCell::typeInfoTypeOffset()), TrustedImm32(JSFunctionType)));
    loadPtr(Address(calleeReg, JSFunction::offsetOfRareData()), rareDataReg);
    addSlowCase(branchTestPtr(Zero, rareDataReg));
    load32(Address(rareDataReg, FunctionRareData::offsetOfObjectAllocationProfile() + ObjectAllocationProfile::offsetOfAllocator()), allocatorReg);
    loadPtr(Address(rareDataReg, FunctionRareData::offsetOfObjectAllocationProfile() + ObjectAllocationProfile::offsetOfStructure()), structureReg);
    addSlowCase(branch32(Equal, allocatorReg, TrustedImm32(Allocator().offset())));

    loadPtr(cachedFunction, cachedFunctionReg);
    Jump hasSeenMultipleCallees = branchPtr(Equal, cachedFunctionReg, TrustedImmPtr(JSCell::seenMultipleCalleeObjects()));
    addSlowCase(branchPtr(NotEqual, calleeReg, cachedFunctionReg));
    hasSeenMultipleCallees.link(this);

    JumpList slowCases;
    auto butterfly = TrustedImmPtr(nullptr);
    auto mask = TrustedImm32(0);
    emitAllocateJSObject(resultReg, JITAllocator::variable(), allocatorReg, structureReg, butterfly, mask, scratchReg, slowCases);
    addSlowCase(slowCases);
    emitStoreCell(currentInstruction[1].u.operand, resultReg);
}

void JIT::emit_op_to_this(Instruction* currentInstruction)
{
    WriteBarrierBase<Structure>* cachedStructure = &currentInstruction[2].u.structure;
    int thisRegister = currentInstruction[1].u.operand;

    emitLoad(thisRegister, regT3, regT2);

    addSlowCase(branch32(NotEqual, regT3, TrustedImm32(JSValue::CellTag)));
    addSlowCase(branch8(NotEqual, Address(regT2, JSCell::typeInfoTypeOffset()), TrustedImm32(FinalObjectType)));
    loadPtr(Address(regT2, JSCell::structureIDOffset()), regT0);
    loadPtr(cachedStructure, regT2);
    addSlowCase(branchPtr(NotEqual, regT0, regT2));
}

void JIT::emit_op_check_tdz(Instruction* currentInstruction)
{
    emitLoadTag(currentInstruction[1].u.operand, regT0);
    addSlowCase(branch32(Equal, regT0, TrustedImm32(JSValue::EmptyValueTag)));
}

void JIT::emit_op_has_structure_property(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int base = currentInstruction[2].u.operand;
    int enumerator = currentInstruction[4].u.operand;

    emitLoadPayload(base, regT0);
    emitJumpSlowCaseIfNotJSCell(base);

    emitLoadPayload(enumerator, regT1);

    load32(Address(regT0, JSCell::structureIDOffset()), regT0);
    addSlowCase(branch32(NotEqual, regT0, Address(regT1, JSPropertyNameEnumerator::cachedStructureIDOffset())));
    
    move(TrustedImm32(1), regT0);
    emitStoreBool(dst, regT0);
}

void JIT::privateCompileHasIndexedProperty(ByValInfo* byValInfo, ReturnAddressPtr returnAddress, JITArrayMode arrayMode)
{
    Instruction* currentInstruction = m_codeBlock->instructions().begin() + byValInfo->bytecodeIndex;
    
    PatchableJump badType;
    
    // FIXME: Add support for other types like TypedArrays and Arguments.
    // See https://bugs.webkit.org/show_bug.cgi?id=135033 and https://bugs.webkit.org/show_bug.cgi?id=135034.
    JumpList slowCases = emitLoadForArrayMode(currentInstruction, arrayMode, badType);
    move(TrustedImm32(1), regT0);
    Jump done = jump();

    LinkBuffer patchBuffer(*this, m_codeBlock);
    
    patchBuffer.link(badType, CodeLocationLabel(MacroAssemblerCodePtr::createFromExecutableAddress(returnAddress.value())).labelAtOffset(byValInfo->returnAddressToSlowPath));
    patchBuffer.link(slowCases, CodeLocationLabel(MacroAssemblerCodePtr::createFromExecutableAddress(returnAddress.value())).labelAtOffset(byValInfo->returnAddressToSlowPath));
    
    patchBuffer.link(done, byValInfo->badTypeJump.labelAtOffset(byValInfo->badTypeJumpToDone));
    
    byValInfo->stubRoutine = FINALIZE_CODE_FOR_STUB(
        m_codeBlock, patchBuffer,
        ("Baseline has_indexed_property stub for %s, return point %p", toCString(*m_codeBlock).data(), returnAddress.value()));
    
    MacroAssembler::repatchJump(byValInfo->badTypeJump, CodeLocationLabel(byValInfo->stubRoutine->code().code()));
    MacroAssembler::repatchCall(CodeLocationCall(MacroAssemblerCodePtr(returnAddress)), FunctionPtr(operationHasIndexedPropertyGeneric));
}

void JIT::emit_op_has_indexed_property(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int base = currentInstruction[2].u.operand;
    int property = currentInstruction[3].u.operand;
    ArrayProfile* profile = currentInstruction[4].u.arrayProfile;
    ByValInfo* byValInfo = m_codeBlock->addByValInfo();
    
    emitLoadPayload(base, regT0);
    emitJumpSlowCaseIfNotJSCell(base);

    emitLoadPayload(property, 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 will 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);

    emitArrayProfilingSiteWithCell(regT0, regT2, profile);
    and32(TrustedImm32(IndexingShapeMask), regT2);

    JITArrayMode mode = chooseArrayMode(profile);
    PatchableJump badType;

    // FIXME: Add support for other types like TypedArrays and Arguments.
    // See https://bugs.webkit.org/show_bug.cgi?id=135033 and https://bugs.webkit.org/show_bug.cgi?id=135034.
    JumpList slowCases = emitLoadForArrayMode(currentInstruction, mode, badType);
    move(TrustedImm32(1), regT0);

    addSlowCase(badType);
    addSlowCase(slowCases);
    
    Label done = label();
    
    emitStoreBool(dst, regT0);

    Label nextHotPath = label();
    
    m_byValCompilationInfo.append(ByValCompilationInfo(byValInfo, m_bytecodeOffset, PatchableJump(), badType, mode, profile, done, nextHotPath));
}

void JIT::emitSlow_op_has_indexed_property(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
{
    linkAllSlowCases(iter);

    int dst = currentInstruction[1].u.operand;
    int base = currentInstruction[2].u.operand;
    int property = currentInstruction[3].u.operand;
    ByValInfo* byValInfo = m_byValCompilationInfo[m_byValInstructionIndex].byValInfo;

    Label slowPath = label();
    
    emitLoad(base, regT1, regT0);
    emitLoad(property, regT3, regT2);
    Call call = callOperation(operationHasIndexedPropertyDefault, dst, regT1, regT0, regT3, regT2, byValInfo);

    m_byValCompilationInfo[m_byValInstructionIndex].slowPathTarget = slowPath;
    m_byValCompilationInfo[m_byValInstructionIndex].returnAddress = call;
    m_byValInstructionIndex++;
}

void JIT::emit_op_get_direct_pname(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int base = currentInstruction[2].u.operand;
    int index = currentInstruction[4].u.operand;
    int enumerator = currentInstruction[5].u.operand;

    // Check that base is a cell
    emitLoadPayload(base, regT0);
    emitJumpSlowCaseIfNotJSCell(base);

    // Check the structure
    emitLoadPayload(enumerator, regT1);
    load32(Address(regT0, JSCell::structureIDOffset()), regT2);
    addSlowCase(branch32(NotEqual, regT2, Address(regT1, JSPropertyNameEnumerator::cachedStructureIDOffset())));

    // Compute the offset
    emitLoadPayload(index, regT2);
    // If index is less than the enumerator's cached inline storage, then it's an inline access
    Jump outOfLineAccess = branch32(AboveOrEqual, regT2, Address(regT1, JSPropertyNameEnumerator::cachedInlineCapacityOffset()));
    addPtr(TrustedImm32(JSObject::offsetOfInlineStorage()), regT0);
    load32(BaseIndex(regT0, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);
    load32(BaseIndex(regT0, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
    
    Jump done = jump();

    // Otherwise it's out of line
    outOfLineAccess.link(this);
    loadPtr(Address(regT0, JSObject::butterflyOffset()), regT0);
    sub32(Address(regT1, JSPropertyNameEnumerator::cachedInlineCapacityOffset()), regT2);
    neg32(regT2);
    int32_t offsetOfFirstProperty = static_cast<int32_t>(offsetInButterfly(firstOutOfLineOffset)) * sizeof(EncodedJSValue);
    load32(BaseIndex(regT0, regT2, TimesEight, offsetOfFirstProperty + OBJECT_OFFSETOF(JSValue, u.asBits.tag)), regT1);
    load32(BaseIndex(regT0, regT2, TimesEight, offsetOfFirstProperty + OBJECT_OFFSETOF(JSValue, u.asBits.payload)), regT0);
    
    done.link(this);
    emitValueProfilingSite();
    emitStore(dst, regT1, regT0);
}

void JIT::emit_op_enumerator_structure_pname(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int enumerator = currentInstruction[2].u.operand;
    int index = currentInstruction[3].u.operand;

    emitLoadPayload(index, regT0);
    emitLoadPayload(enumerator, regT1);
    Jump inBounds = branch32(Below, regT0, Address(regT1, JSPropertyNameEnumerator::endStructurePropertyIndexOffset()));

    move(TrustedImm32(JSValue::NullTag), regT2);
    move(TrustedImm32(0), regT0);

    Jump done = jump();
    inBounds.link(this);

    loadPtr(Address(regT1, JSPropertyNameEnumerator::cachedPropertyNamesVectorOffset()), regT1);
    loadPtr(BaseIndex(regT1, regT0, timesPtr()), regT0);
    move(TrustedImm32(JSValue::CellTag), regT2);

    done.link(this);
    emitStore(dst, regT2, regT0);
}

void JIT::emit_op_enumerator_generic_pname(Instruction* currentInstruction)
{
    int dst = currentInstruction[1].u.operand;
    int enumerator = currentInstruction[2].u.operand;
    int index = currentInstruction[3].u.operand;

    emitLoadPayload(index, regT0);
    emitLoadPayload(enumerator, regT1);
    Jump inBounds = branch32(Below, regT0, Address(regT1, JSPropertyNameEnumerator::endGenericPropertyIndexOffset()));

    move(TrustedImm32(JSValue::NullTag), regT2);
    move(TrustedImm32(0), regT0);

    Jump done = jump();
    inBounds.link(this);

    loadPtr(Address(regT1, JSPropertyNameEnumerator::cachedPropertyNamesVectorOffset()), regT1);
    loadPtr(BaseIndex(regT1, regT0, timesPtr()), regT0);
    move(TrustedImm32(JSValue::CellTag), regT2);
    
    done.link(this);
    emitStore(dst, regT2, regT0);
}

void JIT::emit_op_profile_type(Instruction* currentInstruction)
{
    TypeLocation* cachedTypeLocation = currentInstruction[2].u.location;
    int valueToProfile = currentInstruction[1].u.operand;

    // Load payload in T0. Load tag in T3.
    emitLoadPayload(valueToProfile, regT0);
    emitLoadTag(valueToProfile, regT3);

    JumpList jumpToEnd;

    jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::EmptyValueTag)));

    // Compile in a predictive type check, if possible, to see if we can skip writing to the log.
    // These typechecks are inlined to match those of the 32-bit JSValue type checks.
    if (cachedTypeLocation->m_lastSeenType == TypeUndefined)
        jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::UndefinedTag)));
    else if (cachedTypeLocation->m_lastSeenType == TypeNull)
        jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::NullTag)));
    else if (cachedTypeLocation->m_lastSeenType == TypeBoolean)
        jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::BooleanTag)));
    else if (cachedTypeLocation->m_lastSeenType == TypeAnyInt)
        jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::Int32Tag)));
    else if (cachedTypeLocation->m_lastSeenType == TypeNumber) {
        jumpToEnd.append(branch32(Below, regT3, TrustedImm32(JSValue::LowestTag)));
        jumpToEnd.append(branch32(Equal, regT3, TrustedImm32(JSValue::Int32Tag)));
    } else if (cachedTypeLocation->m_lastSeenType == TypeString) {
        Jump isNotCell = branch32(NotEqual, regT3, TrustedImm32(JSValue::CellTag));
        jumpToEnd.append(branch8(Equal, Address(regT0, JSCell::typeInfoTypeOffset()), TrustedImm32(StringType)));
        isNotCell.link(this);
    }

    // Load the type profiling log into T2.
    TypeProfilerLog* cachedTypeProfilerLog = m_vm->typeProfilerLog();
    move(TrustedImmPtr(cachedTypeProfilerLog), regT2);

    // Load the next log entry into T1.
    loadPtr(Address(regT2, TypeProfilerLog::currentLogEntryOffset()), regT1);

    // Store the JSValue onto the log entry.
    store32(regT0, Address(regT1, TypeProfilerLog::LogEntry::valueOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.payload)));
    store32(regT3, Address(regT1, TypeProfilerLog::LogEntry::valueOffset() + OBJECT_OFFSETOF(JSValue, u.asBits.tag)));

    // Store the structureID of the cell if argument is a cell, otherwise, store 0 on the log entry.
    Jump notCell = branch32(NotEqual, regT3, TrustedImm32(JSValue::CellTag));
    load32(Address(regT0, JSCell::structureIDOffset()), regT0);
    store32(regT0, Address(regT1, TypeProfilerLog::LogEntry::structureIDOffset()));
    Jump skipNotCell = jump();
    notCell.link(this);
    store32(TrustedImm32(0), Address(regT1, TypeProfilerLog::LogEntry::structureIDOffset()));
    skipNotCell.link(this);

    // Store the typeLocation on the log entry.
    move(TrustedImmPtr(cachedTypeLocation), regT0);
    store32(regT0, Address(regT1, TypeProfilerLog::LogEntry::locationOffset()));

    // Increment the current log entry.
    addPtr(TrustedImm32(sizeof(TypeProfilerLog::LogEntry)), regT1);
    store32(regT1, Address(regT2, TypeProfilerLog::currentLogEntryOffset()));
    jumpToEnd.append(branchPtr(NotEqual, regT1, TrustedImmPtr(cachedTypeProfilerLog->logEndPtr())));
    // Clear the log if we're at the end of the log.
    callOperation(operationProcessTypeProfilerLog);

    jumpToEnd.link(this);
}

void JIT::emit_op_log_shadow_chicken_prologue(Instruction* currentInstruction)
{
    updateTopCallFrame();
    static_assert(nonArgGPR0 != regT0 && nonArgGPR0 != regT2, "we will have problems if this is true.");
    GPRReg shadowPacketReg = regT0;
    GPRReg scratch1Reg = nonArgGPR0; // This must be a non-argument register.
    GPRReg scratch2Reg = regT2;
    ensureShadowChickenPacket(*vm(), shadowPacketReg, scratch1Reg, scratch2Reg);

    scratch1Reg = regT4;
    emitLoadPayload(currentInstruction[1].u.operand, regT3);
    logShadowChickenProloguePacket(shadowPacketReg, scratch1Reg, regT3);
}

void JIT::emit_op_log_shadow_chicken_tail(Instruction* currentInstruction)
{
    updateTopCallFrame();
    static_assert(nonArgGPR0 != regT0 && nonArgGPR0 != regT2, "we will have problems if this is true.");
    GPRReg shadowPacketReg = regT0;
    GPRReg scratch1Reg = nonArgGPR0; // This must be a non-argument register.
    GPRReg scratch2Reg = regT2;
    ensureShadowChickenPacket(*vm(), shadowPacketReg, scratch1Reg, scratch2Reg);

    emitLoadPayload(currentInstruction[1].u.operand, regT2);
    emitLoadTag(currentInstruction[1].u.operand, regT1);
    JSValueRegs thisRegs(regT1, regT2);
    emitLoadPayload(currentInstruction[2].u.operand, regT3);
    logShadowChickenTailPacket(shadowPacketReg, thisRegs, regT3, m_codeBlock, CallSiteIndex(currentInstruction));
}

} // namespace JSC

#endif // USE(JSVALUE32_64)
#endif // ENABLE(JIT)