DFG del_by_id support forgets to set()

[WebKit-https.git] / Source / JavaScriptCore / dfg / DFGByteCodeParser.cpp

/*
 * Copyright (C) 2011-2016 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"
#include "DFGByteCodeParser.h"

#if ENABLE(DFG_JIT)

#include "ArrayConstructor.h"
#include "BasicBlockLocation.h"
#include "CallLinkStatus.h"
#include "CodeBlock.h"
#include "CodeBlockWithJITType.h"
#include "DFGAbstractHeap.h"
#include "DFGArrayMode.h"
#include "DFGCapabilities.h"
#include "DFGClobberize.h"
#include "DFGClobbersExitState.h"
#include "DFGGraph.h"
#include "DFGJITCode.h"
#include "GetByIdStatus.h"
#include "Heap.h"
#include "JSLexicalEnvironment.h"
#include "JSCInlines.h"
#include "JSModuleEnvironment.h"
#include "ObjectConstructor.h"
#include "PreciseJumpTargets.h"
#include "PutByIdFlags.h"
#include "PutByIdStatus.h"
#include "StackAlignment.h"
#include "StringConstructor.h"
#include "StructureStubInfo.h"
#include "Watchdog.h"
#include <wtf/CommaPrinter.h>
#include <wtf/HashMap.h>
#include <wtf/MathExtras.h>
#include <wtf/StdLibExtras.h>

namespace JSC { namespace DFG {

static const bool verbose = false;

class ConstantBufferKey {
public:
    ConstantBufferKey()
        : m_codeBlock(0)
        , m_index(0)
    {
    }
    
    ConstantBufferKey(WTF::HashTableDeletedValueType)
        : m_codeBlock(0)
        , m_index(1)
    {
    }
    
    ConstantBufferKey(CodeBlock* codeBlock, unsigned index)
        : m_codeBlock(codeBlock)
        , m_index(index)
    {
    }
    
    bool operator==(const ConstantBufferKey& other) const
    {
        return m_codeBlock == other.m_codeBlock
            && m_index == other.m_index;
    }
    
    unsigned hash() const
    {
        return WTF::PtrHash<CodeBlock*>::hash(m_codeBlock) ^ m_index;
    }
    
    bool isHashTableDeletedValue() const
    {
        return !m_codeBlock && m_index;
    }
    
    CodeBlock* codeBlock() const { return m_codeBlock; }
    unsigned index() const { return m_index; }
    
private:
    CodeBlock* m_codeBlock;
    unsigned m_index;
};

struct ConstantBufferKeyHash {
    static unsigned hash(const ConstantBufferKey& key) { return key.hash(); }
    static bool equal(const ConstantBufferKey& a, const ConstantBufferKey& b)
    {
        return a == b;
    }
    
    static const bool safeToCompareToEmptyOrDeleted = true;
};

} } // namespace JSC::DFG

namespace WTF {

template<typename T> struct DefaultHash;
template<> struct DefaultHash<JSC::DFG::ConstantBufferKey> {
    typedef JSC::DFG::ConstantBufferKeyHash Hash;
};

template<typename T> struct HashTraits;
template<> struct HashTraits<JSC::DFG::ConstantBufferKey> : SimpleClassHashTraits<JSC::DFG::ConstantBufferKey> { };

} // namespace WTF

namespace JSC { namespace DFG {

// === ByteCodeParser ===
//
// This class is used to compile the dataflow graph from a CodeBlock.
class ByteCodeParser {
public:
    ByteCodeParser(Graph& graph)
        : m_vm(&graph.m_vm)
        , m_codeBlock(graph.m_codeBlock)
        , m_profiledBlock(graph.m_profiledBlock)
        , m_graph(graph)
        , m_currentBlock(0)
        , m_currentIndex(0)
        , m_constantUndefined(graph.freeze(jsUndefined()))
        , m_constantNull(graph.freeze(jsNull()))
        , m_constantNaN(graph.freeze(jsNumber(PNaN)))
        , m_constantOne(graph.freeze(jsNumber(1)))
        , m_numArguments(m_codeBlock->numParameters())
        , m_numLocals(m_codeBlock->m_numCalleeLocals)
        , m_parameterSlots(0)
        , m_numPassedVarArgs(0)
        , m_inlineStackTop(0)
        , m_currentInstruction(0)
        , m_hasDebuggerEnabled(graph.hasDebuggerEnabled())
    {
        ASSERT(m_profiledBlock);
    }
    
    // Parse a full CodeBlock of bytecode.
    bool parse();
    
private:
    struct InlineStackEntry;

    // Just parse from m_currentIndex to the end of the current CodeBlock.
    void parseCodeBlock();
    
    void ensureLocals(unsigned newNumLocals)
    {
        if (newNumLocals <= m_numLocals)
            return;
        m_numLocals = newNumLocals;
        for (size_t i = 0; i < m_graph.numBlocks(); ++i)
            m_graph.block(i)->ensureLocals(newNumLocals);
    }

    // Helper for min and max.
    template<typename ChecksFunctor>
    bool handleMinMax(int resultOperand, NodeType op, int registerOffset, int argumentCountIncludingThis, const ChecksFunctor& insertChecks);

    void refineStatically(CallLinkStatus&, Node* callTarget);
    // Handle calls. This resolves issues surrounding inlining and intrinsics.
    enum Terminality { Terminal, NonTerminal };
    Terminality handleCall(
        int result, NodeType op, InlineCallFrame::Kind, unsigned instructionSize,
        Node* callTarget, int argCount, int registerOffset, CallLinkStatus,
        SpeculatedType prediction);
    Terminality handleCall(
        int result, NodeType op, CallMode, unsigned instructionSize,
        Node* callTarget, int argCount, int registerOffset, CallLinkStatus);
    Terminality handleCall(int result, NodeType op, CallMode, unsigned instructionSize, int callee, int argCount, int registerOffset);
    Terminality handleCall(Instruction* pc, NodeType op, CallMode);
    Terminality handleVarargsCall(Instruction* pc, NodeType op, CallMode);
    void emitFunctionChecks(CallVariant, Node* callTarget, VirtualRegister thisArgumnt);
    void emitArgumentPhantoms(int registerOffset, int argumentCountIncludingThis);
    unsigned inliningCost(CallVariant, int argumentCountIncludingThis, CallMode); // Return UINT_MAX if it's not an inlining candidate. By convention, intrinsics have a cost of 1.
    // Handle inlining. Return true if it succeeded, false if we need to plant a call.
    bool handleInlining(Node* callTargetNode, int resultOperand, const CallLinkStatus&, int registerOffset, VirtualRegister thisArgument, VirtualRegister argumentsArgument, unsigned argumentsOffset, int argumentCountIncludingThis, unsigned nextOffset, NodeType callOp, InlineCallFrame::Kind, SpeculatedType prediction);
    enum CallerLinkability { CallerDoesNormalLinking, CallerLinksManually };
    template<typename ChecksFunctor>
    bool attemptToInlineCall(Node* callTargetNode, int resultOperand, CallVariant, int registerOffset, int argumentCountIncludingThis, unsigned nextOffset, InlineCallFrame::Kind, CallerLinkability, SpeculatedType prediction, unsigned& inliningBalance, const ChecksFunctor& insertChecks);
    template<typename ChecksFunctor>
    void inlineCall(Node* callTargetNode, int resultOperand, CallVariant, int registerOffset, int argumentCountIncludingThis, unsigned nextOffset, InlineCallFrame::Kind, CallerLinkability, const ChecksFunctor& insertChecks);
    void cancelLinkingForBlock(InlineStackEntry*, BasicBlock*); // Only works when the given block is the last one to have been added for that inline stack entry.
    // Handle intrinsic functions. Return true if it succeeded, false if we need to plant a call.
    template<typename ChecksFunctor>
    bool handleIntrinsicCall(Node* callee, int resultOperand, Intrinsic, int registerOffset, int argumentCountIncludingThis, SpeculatedType prediction, const ChecksFunctor& insertChecks);
    template<typename ChecksFunctor>
    bool handleIntrinsicGetter(int resultOperand, const GetByIdVariant& intrinsicVariant, Node* thisNode, const ChecksFunctor& insertChecks);
    template<typename ChecksFunctor>
    bool handleTypedArrayConstructor(int resultOperand, InternalFunction*, int registerOffset, int argumentCountIncludingThis, TypedArrayType, const ChecksFunctor& insertChecks);
    template<typename ChecksFunctor>
    bool handleConstantInternalFunction(Node* callTargetNode, int resultOperand, InternalFunction*, int registerOffset, int argumentCountIncludingThis, CodeSpecializationKind, const ChecksFunctor& insertChecks);
    Node* handlePutByOffset(Node* base, unsigned identifier, PropertyOffset, const InferredType::Descriptor&, Node* value);
    Node* handleGetByOffset(SpeculatedType, Node* base, unsigned identifierNumber, PropertyOffset, const InferredType::Descriptor&, NodeType = GetByOffset);

    // Create a presence ObjectPropertyCondition based on some known offset and structure set. Does not
    // check the validity of the condition, but it may return a null one if it encounters a contradiction.
    ObjectPropertyCondition presenceLike(
        JSObject* knownBase, UniquedStringImpl*, PropertyOffset, const StructureSet&);
    
    // Attempt to watch the presence of a property. It will watch that the property is present in the same
    // way as in all of the structures in the set. It may emit code instead of just setting a watchpoint.
    // Returns true if this all works out.
    bool checkPresenceLike(JSObject* knownBase, UniquedStringImpl*, PropertyOffset, const StructureSet&);
    void checkPresenceLike(Node* base, UniquedStringImpl*, PropertyOffset, const StructureSet&);
    
    // Works with both GetByIdVariant and the setter form of PutByIdVariant.
    template<typename VariantType>
    Node* load(SpeculatedType, Node* base, unsigned identifierNumber, const VariantType&);

    Node* store(Node* base, unsigned identifier, const PutByIdVariant&, Node* value);

    void handleTryGetById(int destinationOperand, Node* base, unsigned identifierNumber, const GetByIdStatus&);
    void handleGetById(
        int destinationOperand, SpeculatedType, Node* base, unsigned identifierNumber, GetByIdStatus, AccessType);
    void emitPutById(
        Node* base, unsigned identifierNumber, Node* value,  const PutByIdStatus&, bool isDirect);
    void handlePutById(
        Node* base, unsigned identifierNumber, Node* value, const PutByIdStatus&,
        bool isDirect);
    
    // Either register a watchpoint or emit a check for this condition. Returns false if the
    // condition no longer holds, and therefore no reasonable check can be emitted.
    bool check(const ObjectPropertyCondition&);
    
    GetByOffsetMethod promoteToConstant(GetByOffsetMethod);
    
    // Either register a watchpoint or emit a check for this condition. It must be a Presence
    // condition. It will attempt to promote a Presence condition to an Equivalence condition.
    // Emits code for the loaded value that the condition guards, and returns a node containing
    // the loaded value. Returns null if the condition no longer holds.
    GetByOffsetMethod planLoad(const ObjectPropertyCondition&);
    Node* load(SpeculatedType, unsigned identifierNumber, const GetByOffsetMethod&, NodeType = GetByOffset);
    Node* load(SpeculatedType, const ObjectPropertyCondition&, NodeType = GetByOffset);
    
    // Calls check() for each condition in the set: that is, it either emits checks or registers
    // watchpoints (or a combination of the two) to make the conditions hold. If any of those
    // conditions are no longer checkable, returns false.
    bool check(const ObjectPropertyConditionSet&);
    
    // Calls check() for those conditions that aren't the slot base, and calls load() for the slot
    // base. Does a combination of watchpoint registration and check emission to guard the
    // conditions, and emits code to load the value from the slot base. Returns a node containing
    // the loaded value. Returns null if any of the conditions were no longer checkable.
    GetByOffsetMethod planLoad(const ObjectPropertyConditionSet&);
    Node* load(SpeculatedType, const ObjectPropertyConditionSet&, NodeType = GetByOffset);

    void prepareToParseBlock();
    void clearCaches();

    // Parse a single basic block of bytecode instructions.
    bool parseBlock(unsigned limit);
    // Link block successors.
    void linkBlock(BasicBlock*, Vector<BasicBlock*>& possibleTargets);
    void linkBlocks(Vector<UnlinkedBlock>& unlinkedBlocks, Vector<BasicBlock*>& possibleTargets);
    
    VariableAccessData* newVariableAccessData(VirtualRegister operand)
    {
        ASSERT(!operand.isConstant());
        
        m_graph.m_variableAccessData.append(VariableAccessData(operand));
        return &m_graph.m_variableAccessData.last();
    }
    
    // Get/Set the operands/result of a bytecode instruction.
    Node* getDirect(VirtualRegister operand)
    {
        ASSERT(!operand.isConstant());

        // Is this an argument?
        if (operand.isArgument())
            return getArgument(operand);

        // Must be a local.
        return getLocal(operand);
    }

    Node* get(VirtualRegister operand)
    {
        if (operand.isConstant()) {
            unsigned constantIndex = operand.toConstantIndex();
            unsigned oldSize = m_constants.size();
            if (constantIndex >= oldSize || !m_constants[constantIndex]) {
                const CodeBlock& codeBlock = *m_inlineStackTop->m_codeBlock;
                JSValue value = codeBlock.getConstant(operand.offset());
                SourceCodeRepresentation sourceCodeRepresentation = codeBlock.constantSourceCodeRepresentation(operand.offset());
                if (constantIndex >= oldSize) {
                    m_constants.grow(constantIndex + 1);
                    for (unsigned i = oldSize; i < m_constants.size(); ++i)
                        m_constants[i] = nullptr;
                }

                Node* constantNode = nullptr;
                if (sourceCodeRepresentation == SourceCodeRepresentation::Double)
                    constantNode = addToGraph(DoubleConstant, OpInfo(m_graph.freezeStrong(jsDoubleNumber(value.asNumber()))));
                else
                    constantNode = addToGraph(JSConstant, OpInfo(m_graph.freezeStrong(value)));
                m_constants[constantIndex] = constantNode;
            }
            ASSERT(m_constants[constantIndex]);
            return m_constants[constantIndex];
        }
        
        if (inlineCallFrame()) {
            if (!inlineCallFrame()->isClosureCall) {
                JSFunction* callee = inlineCallFrame()->calleeConstant();
                if (operand.offset() == JSStack::Callee)
                    return weakJSConstant(callee);
            }
        } else if (operand.offset() == JSStack::Callee) {
            // We have to do some constant-folding here because this enables CreateThis folding. Note
            // that we don't have such watchpoint-based folding for inlined uses of Callee, since in that
            // case if the function is a singleton then we already know it.
            if (FunctionExecutable* executable = jsDynamicCast<FunctionExecutable*>(m_codeBlock->ownerExecutable())) {
                InferredValue* singleton = executable->singletonFunction();
                if (JSValue value = singleton->inferredValue()) {
                    m_graph.watchpoints().addLazily(singleton);
                    JSFunction* function = jsCast<JSFunction*>(value);
                    return weakJSConstant(function);
                }
            }
            return addToGraph(GetCallee);
        }
        
        return getDirect(m_inlineStackTop->remapOperand(operand));
    }
    
    enum SetMode {
        // A normal set which follows a two-phase commit that spans code origins. During
        // the current code origin it issues a MovHint, and at the start of the next
        // code origin there will be a SetLocal. If the local needs flushing, the second
        // SetLocal will be preceded with a Flush.
        NormalSet,
        
        // A set where the SetLocal happens immediately and there is still a Flush. This
        // is relevant when assigning to a local in tricky situations for the delayed
        // SetLocal logic but where we know that we have not performed any side effects
        // within this code origin. This is a safe replacement for NormalSet anytime we
        // know that we have not yet performed side effects in this code origin.
        ImmediateSetWithFlush,
        
        // A set where the SetLocal happens immediately and we do not Flush it even if
        // this is a local that is marked as needing it. This is relevant when
        // initializing locals at the top of a function.
        ImmediateNakedSet
    };
    Node* setDirect(VirtualRegister operand, Node* value, SetMode setMode = NormalSet)
    {
        addToGraph(MovHint, OpInfo(operand.offset()), value);

        // We can't exit anymore because our OSR exit state has changed.
        m_exitOK = false;

        DelayedSetLocal delayed(currentCodeOrigin(), operand, value);
        
        if (setMode == NormalSet) {
            m_setLocalQueue.append(delayed);
            return 0;
        }
        
        return delayed.execute(this, setMode);
    }
    
    void processSetLocalQueue()
    {
        for (unsigned i = 0; i < m_setLocalQueue.size(); ++i)
            m_setLocalQueue[i].execute(this);
        m_setLocalQueue.resize(0);
    }

    Node* set(VirtualRegister operand, Node* value, SetMode setMode = NormalSet)
    {
        return setDirect(m_inlineStackTop->remapOperand(operand), value, setMode);
    }
    
    Node* injectLazyOperandSpeculation(Node* node)
    {
        ASSERT(node->op() == GetLocal);
        ASSERT(node->origin.semantic.bytecodeIndex == m_currentIndex);
        ConcurrentJITLocker locker(m_inlineStackTop->m_profiledBlock->m_lock);
        LazyOperandValueProfileKey key(m_currentIndex, node->local());
        SpeculatedType prediction = m_inlineStackTop->m_lazyOperands.prediction(locker, key);
        node->variableAccessData()->predict(prediction);
        return node;
    }

    // Used in implementing get/set, above, where the operand is a local variable.
    Node* getLocal(VirtualRegister operand)
    {
        unsigned local = operand.toLocal();

        Node* node = m_currentBlock->variablesAtTail.local(local);
        
        // This has two goals: 1) link together variable access datas, and 2)
        // try to avoid creating redundant GetLocals. (1) is required for
        // correctness - no other phase will ensure that block-local variable
        // access data unification is done correctly. (2) is purely opportunistic
        // and is meant as an compile-time optimization only.
        
        VariableAccessData* variable;
        
        if (node) {
            variable = node->variableAccessData();
            
            switch (node->op()) {
            case GetLocal:
                return node;
            case SetLocal:
                return node->child1().node();
            default:
                break;
            }
        } else
            variable = newVariableAccessData(operand);
        
        node = injectLazyOperandSpeculation(addToGraph(GetLocal, OpInfo(variable)));
        m_currentBlock->variablesAtTail.local(local) = node;
        return node;
    }
    Node* setLocal(const CodeOrigin& semanticOrigin, VirtualRegister operand, Node* value, SetMode setMode = NormalSet)
    {
        CodeOrigin oldSemanticOrigin = m_currentSemanticOrigin;
        m_currentSemanticOrigin = semanticOrigin;

        unsigned local = operand.toLocal();
        
        if (setMode != ImmediateNakedSet) {
            ArgumentPosition* argumentPosition = findArgumentPositionForLocal(operand);
            if (argumentPosition)
                flushDirect(operand, argumentPosition);
            else if (m_hasDebuggerEnabled && operand == m_codeBlock->scopeRegister())
                flush(operand);
        }

        VariableAccessData* variableAccessData = newVariableAccessData(operand);
        variableAccessData->mergeStructureCheckHoistingFailed(
            m_inlineStackTop->m_exitProfile.hasExitSite(semanticOrigin.bytecodeIndex, BadCache));
        variableAccessData->mergeCheckArrayHoistingFailed(
            m_inlineStackTop->m_exitProfile.hasExitSite(semanticOrigin.bytecodeIndex, BadIndexingType));
        Node* node = addToGraph(SetLocal, OpInfo(variableAccessData), value);
        m_currentBlock->variablesAtTail.local(local) = node;

        m_currentSemanticOrigin = oldSemanticOrigin;
        return node;
    }

    // Used in implementing get/set, above, where the operand is an argument.
    Node* getArgument(VirtualRegister operand)
    {
        unsigned argument = operand.toArgument();
        ASSERT(argument < m_numArguments);
        
        Node* node = m_currentBlock->variablesAtTail.argument(argument);

        VariableAccessData* variable;
        
        if (node) {
            variable = node->variableAccessData();
            
            switch (node->op()) {
            case GetLocal:
                return node;
            case SetLocal:
                return node->child1().node();
            default:
                break;
            }
        } else
            variable = newVariableAccessData(operand);
        
        node = injectLazyOperandSpeculation(addToGraph(GetLocal, OpInfo(variable)));
        m_currentBlock->variablesAtTail.argument(argument) = node;
        return node;
    }
    Node* setArgument(const CodeOrigin& semanticOrigin, VirtualRegister operand, Node* value, SetMode setMode = NormalSet)
    {
        CodeOrigin oldSemanticOrigin = m_currentSemanticOrigin;
        m_currentSemanticOrigin = semanticOrigin;

        unsigned argument = operand.toArgument();
        ASSERT(argument < m_numArguments);
        
        VariableAccessData* variableAccessData = newVariableAccessData(operand);

        // Always flush arguments, except for 'this'. If 'this' is created by us,
        // then make sure that it's never unboxed.
        if (argument) {
            if (setMode != ImmediateNakedSet)
                flushDirect(operand);
        } else if (m_codeBlock->specializationKind() == CodeForConstruct)
            variableAccessData->mergeShouldNeverUnbox(true);
        
        variableAccessData->mergeStructureCheckHoistingFailed(
            m_inlineStackTop->m_exitProfile.hasExitSite(semanticOrigin.bytecodeIndex, BadCache));
        variableAccessData->mergeCheckArrayHoistingFailed(
            m_inlineStackTop->m_exitProfile.hasExitSite(semanticOrigin.bytecodeIndex, BadIndexingType));
        Node* node = addToGraph(SetLocal, OpInfo(variableAccessData), value);
        m_currentBlock->variablesAtTail.argument(argument) = node;

        m_currentSemanticOrigin = oldSemanticOrigin;
        return node;
    }
    
    ArgumentPosition* findArgumentPositionForArgument(int argument)
    {
        InlineStackEntry* stack = m_inlineStackTop;
        while (stack->m_inlineCallFrame)
            stack = stack->m_caller;
        return stack->m_argumentPositions[argument];
    }
    
    ArgumentPosition* findArgumentPositionForLocal(VirtualRegister operand)
    {
        for (InlineStackEntry* stack = m_inlineStackTop; ; stack = stack->m_caller) {
            InlineCallFrame* inlineCallFrame = stack->m_inlineCallFrame;
            if (!inlineCallFrame)
                break;
            if (operand.offset() < static_cast<int>(inlineCallFrame->stackOffset + JSStack::CallFrameHeaderSize))
                continue;
            if (operand.offset() == inlineCallFrame->stackOffset + CallFrame::thisArgumentOffset())
                continue;
            if (operand.offset() >= static_cast<int>(inlineCallFrame->stackOffset + CallFrame::thisArgumentOffset() + inlineCallFrame->arguments.size()))
                continue;
            int argument = VirtualRegister(operand.offset() - inlineCallFrame->stackOffset).toArgument();
            return stack->m_argumentPositions[argument];
        }
        return 0;
    }
    
    ArgumentPosition* findArgumentPosition(VirtualRegister operand)
    {
        if (operand.isArgument())
            return findArgumentPositionForArgument(operand.toArgument());
        return findArgumentPositionForLocal(operand);
    }

    void flush(VirtualRegister operand)
    {
        flushDirect(m_inlineStackTop->remapOperand(operand));
    }
    
    void flushDirect(VirtualRegister operand)
    {
        flushDirect(operand, findArgumentPosition(operand));
    }
    
    void flushDirect(VirtualRegister operand, ArgumentPosition* argumentPosition)
    {
        ASSERT(!operand.isConstant());
        
        Node* node = m_currentBlock->variablesAtTail.operand(operand);
        
        VariableAccessData* variable;
        
        if (node)
            variable = node->variableAccessData();
        else
            variable = newVariableAccessData(operand);
        
        node = addToGraph(Flush, OpInfo(variable));
        m_currentBlock->variablesAtTail.operand(operand) = node;
        if (argumentPosition)
            argumentPosition->addVariable(variable);
    }
    
    void flush(InlineStackEntry* inlineStackEntry)
    {
        int numArguments;
        if (InlineCallFrame* inlineCallFrame = inlineStackEntry->m_inlineCallFrame) {
            ASSERT(!m_hasDebuggerEnabled);
            numArguments = inlineCallFrame->arguments.size();
            if (inlineCallFrame->isClosureCall)
                flushDirect(inlineStackEntry->remapOperand(VirtualRegister(JSStack::Callee)));
            if (inlineCallFrame->isVarargs())
                flushDirect(inlineStackEntry->remapOperand(VirtualRegister(JSStack::ArgumentCount)));
        } else
            numArguments = inlineStackEntry->m_codeBlock->numParameters();
        for (unsigned argument = numArguments; argument-- > 1;)
            flushDirect(inlineStackEntry->remapOperand(virtualRegisterForArgument(argument)));
        if (m_hasDebuggerEnabled)
            flush(m_codeBlock->scopeRegister());
    }

    void flushForTerminal()
    {
        for (InlineStackEntry* inlineStackEntry = m_inlineStackTop; inlineStackEntry; inlineStackEntry = inlineStackEntry->m_caller)
            flush(inlineStackEntry);
    }

    void flushForReturn()
    {
        flush(m_inlineStackTop);
    }
    
    void flushIfTerminal(SwitchData& data)
    {
        if (data.fallThrough.bytecodeIndex() > m_currentIndex)
            return;
        
        for (unsigned i = data.cases.size(); i--;) {
            if (data.cases[i].target.bytecodeIndex() > m_currentIndex)
                return;
        }
        
        flushForTerminal();
    }

    // Assumes that the constant should be strongly marked.
    Node* jsConstant(JSValue constantValue)
    {
        return addToGraph(JSConstant, OpInfo(m_graph.freezeStrong(constantValue)));
    }

    Node* weakJSConstant(JSValue constantValue)
    {
        return addToGraph(JSConstant, OpInfo(m_graph.freeze(constantValue)));
    }

    // Helper functions to get/set the this value.
    Node* getThis()
    {
        return get(m_inlineStackTop->m_codeBlock->thisRegister());
    }

    void setThis(Node* value)
    {
        set(m_inlineStackTop->m_codeBlock->thisRegister(), value);
    }

    InlineCallFrame* inlineCallFrame()
    {
        return m_inlineStackTop->m_inlineCallFrame;
    }

    bool allInlineFramesAreTailCalls()
    {
        return !inlineCallFrame() || !inlineCallFrame()->getCallerSkippingTailCalls();
    }

    CodeOrigin currentCodeOrigin()
    {
        return CodeOrigin(m_currentIndex, inlineCallFrame());
    }

    NodeOrigin currentNodeOrigin()
    {
        CodeOrigin semantic;
        CodeOrigin forExit;

        if (m_currentSemanticOrigin.isSet())
            semantic = m_currentSemanticOrigin;
        else
            semantic = currentCodeOrigin();

        forExit = currentCodeOrigin();

        return NodeOrigin(semantic, forExit, m_exitOK);
    }
    
    BranchData* branchData(unsigned taken, unsigned notTaken)
    {
        // We assume that branches originating from bytecode always have a fall-through. We
        // use this assumption to avoid checking for the creation of terminal blocks.
        ASSERT((taken > m_currentIndex) || (notTaken > m_currentIndex));
        BranchData* data = m_graph.m_branchData.add();
        *data = BranchData::withBytecodeIndices(taken, notTaken);
        return data;
    }
    
    Node* addToGraph(Node* node)
    {
        if (Options::verboseDFGByteCodeParsing())
            dataLog("        appended ", node, " ", Graph::opName(node->op()), "\n");
        m_currentBlock->append(node);
        if (clobbersExitState(m_graph, node))
            m_exitOK = false;
        return node;
    }
    
    Node* addToGraph(NodeType op, Node* child1 = 0, Node* child2 = 0, Node* child3 = 0)
    {
        Node* result = m_graph.addNode(
            SpecNone, op, currentNodeOrigin(), Edge(child1), Edge(child2),
            Edge(child3));
        return addToGraph(result);
    }
    Node* addToGraph(NodeType op, Edge child1, Edge child2 = Edge(), Edge child3 = Edge())
    {
        Node* result = m_graph.addNode(
            SpecNone, op, currentNodeOrigin(), child1, child2, child3);
        return addToGraph(result);
    }
    Node* addToGraph(NodeType op, OpInfo info, Node* child1 = 0, Node* child2 = 0, Node* child3 = 0)
    {
        Node* result = m_graph.addNode(
            SpecNone, op, currentNodeOrigin(), info, Edge(child1), Edge(child2),
            Edge(child3));
        return addToGraph(result);
    }
    Node* addToGraph(NodeType op, OpInfo info1, OpInfo info2, Node* child1 = 0, Node* child2 = 0, Node* child3 = 0)
    {
        Node* result = m_graph.addNode(
            SpecNone, op, currentNodeOrigin(), info1, info2,
            Edge(child1), Edge(child2), Edge(child3));
        return addToGraph(result);
    }
    
    Node* addToGraph(Node::VarArgTag, NodeType op, OpInfo info1, OpInfo info2)
    {
        Node* result = m_graph.addNode(
            SpecNone, Node::VarArg, op, currentNodeOrigin(), info1, info2,
            m_graph.m_varArgChildren.size() - m_numPassedVarArgs, m_numPassedVarArgs);
        addToGraph(result);
        
        m_numPassedVarArgs = 0;
        
        return result;
    }
    
    void addVarArgChild(Node* child)
    {
        m_graph.m_varArgChildren.append(Edge(child));
        m_numPassedVarArgs++;
    }
    
    Node* addCallWithoutSettingResult(
        NodeType op, OpInfo opInfo, Node* callee, int argCount, int registerOffset,
        OpInfo prediction)
    {
        addVarArgChild(callee);
        size_t frameSize = JSStack::CallFrameHeaderSize + argCount;
        size_t alignedFrameSize = WTF::roundUpToMultipleOf(stackAlignmentRegisters(), frameSize);
        size_t parameterSlots = alignedFrameSize - JSStack::CallerFrameAndPCSize;

        if (parameterSlots > m_parameterSlots)
            m_parameterSlots = parameterSlots;

        for (int i = 0; i < argCount; ++i)
            addVarArgChild(get(virtualRegisterForArgument(i, registerOffset)));

        return addToGraph(Node::VarArg, op, opInfo, prediction);
    }
    
    Node* addCall(
        int result, NodeType op, OpInfo opInfo, Node* callee, int argCount, int registerOffset,
        SpeculatedType prediction)
    {
        if (op == TailCall) {
            if (allInlineFramesAreTailCalls())
                return addCallWithoutSettingResult(op, OpInfo(), callee, argCount, registerOffset, OpInfo());
            op = TailCallInlinedCaller;
        }


        Node* call = addCallWithoutSettingResult(
            op, opInfo, callee, argCount, registerOffset, OpInfo(prediction));
        VirtualRegister resultReg(result);
        if (resultReg.isValid())
            set(resultReg, call);
        return call;
    }
    
    Node* cellConstantWithStructureCheck(JSCell* object, Structure* structure)
    {
        // FIXME: This should route to emitPropertyCheck, not the other way around. But currently,
        // this gets no profit from using emitPropertyCheck() since we'll non-adaptively watch the
        // object's structure as soon as we make it a weakJSCosntant.
        Node* objectNode = weakJSConstant(object);
        addToGraph(CheckStructure, OpInfo(m_graph.addStructureSet(structure)), objectNode);
        return objectNode;
    }
    
    SpeculatedType getPredictionWithoutOSRExit(unsigned bytecodeIndex)
    {
        SpeculatedType prediction;
        CodeBlock* profiledBlock = nullptr;

        {
            ConcurrentJITLocker locker(m_inlineStackTop->m_profiledBlock->m_lock);
            prediction = m_inlineStackTop->m_profiledBlock->valueProfilePredictionForBytecodeOffset(locker, bytecodeIndex);

            if (prediction == SpecNone) {
                // If we have no information about the values this
                // node generates, we check if by any chance it is
                // a tail call opcode. In that case, we walk up the
                // inline frames to find a call higher in the call
                // chain and use its prediction. If we only have
                // inlined tail call frames, we use SpecFullTop
                // to avoid a spurious OSR exit.
                Instruction* instruction = m_inlineStackTop->m_profiledBlock->instructions().begin() + bytecodeIndex;
                OpcodeID opcodeID = m_vm->interpreter->getOpcodeID(instruction->u.opcode);

                switch (opcodeID) {
                case op_tail_call:
                case op_tail_call_varargs: {
                    if (!inlineCallFrame()) {
                        prediction = SpecFullTop;
                        break;
                    }
                    CodeOrigin* codeOrigin = inlineCallFrame()->getCallerSkippingTailCalls();
                    if (!codeOrigin) {
                        prediction = SpecFullTop;
                        break;
                    }
                    InlineStackEntry* stack = m_inlineStackTop;
                    while (stack->m_inlineCallFrame != codeOrigin->inlineCallFrame)
                        stack = stack->m_caller;
                    bytecodeIndex = codeOrigin->bytecodeIndex;
                    profiledBlock = stack->m_profiledBlock;
                    break;
                }

                default:
                    break;
                }
            }
        }

        if (profiledBlock) {
            ConcurrentJITLocker locker(profiledBlock->m_lock);
            prediction = profiledBlock->valueProfilePredictionForBytecodeOffset(locker, bytecodeIndex);
        }

        return prediction;
    }

    SpeculatedType getPrediction(unsigned bytecodeIndex)
    {
        SpeculatedType prediction = getPredictionWithoutOSRExit(bytecodeIndex);

        if (prediction == SpecNone) {
            // We have no information about what values this node generates. Give up
            // on executing this code, since we're likely to do more damage than good.
            addToGraph(ForceOSRExit);
        }
        
        return prediction;
    }
    
    SpeculatedType getPredictionWithoutOSRExit()
    {
        return getPredictionWithoutOSRExit(m_currentIndex);
    }
    
    SpeculatedType getPrediction()
    {
        return getPrediction(m_currentIndex);
    }
    
    ArrayMode getArrayMode(ArrayProfile* profile, Array::Action action)
    {
        ConcurrentJITLocker locker(m_inlineStackTop->m_profiledBlock->m_lock);
        profile->computeUpdatedPrediction(locker, m_inlineStackTop->m_profiledBlock);
        bool makeSafe = profile->outOfBounds(locker);
        return ArrayMode::fromObserved(locker, profile, action, makeSafe);
    }
    
    ArrayMode getArrayMode(ArrayProfile* profile)
    {
        return getArrayMode(profile, Array::Read);
    }
    
    Node* makeSafe(Node* node)
    {
        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, Overflow))
            node->mergeFlags(NodeMayOverflowInt32InDFG);
        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, NegativeZero))
            node->mergeFlags(NodeMayNegZeroInDFG);
        
        if (!isX86() && node->op() == ArithMod)
            return node;

        if (!m_inlineStackTop->m_profiledBlock->likelyToTakeSlowCase(m_currentIndex))
            return node;
        
        switch (node->op()) {
        case UInt32ToNumber:
        case ArithAdd:
        case ArithSub:
        case ValueAdd:
        case ArithMod: // for ArithMod "MayOverflow" means we tried to divide by zero, or we saw double.
            node->mergeFlags(NodeMayOverflowInt32InBaseline);
            break;
            
        case ArithNegate:
            // Currently we can't tell the difference between a negation overflowing
            // (i.e. -(1 << 31)) or generating negative zero (i.e. -0). If it took slow
            // path then we assume that it did both of those things.
            node->mergeFlags(NodeMayOverflowInt32InBaseline);
            node->mergeFlags(NodeMayNegZeroInBaseline);
            break;

        case ArithMul: {
            ResultProfile& resultProfile = *m_inlineStackTop->m_profiledBlock->resultProfileForBytecodeOffset(m_currentIndex);
            if (resultProfile.didObserveInt52Overflow())
                node->mergeFlags(NodeMayOverflowInt52);
            if (resultProfile.didObserveInt32Overflow() || m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, Overflow))
                node->mergeFlags(NodeMayOverflowInt32InBaseline);
            if (resultProfile.didObserveNegZeroDouble() || m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, NegativeZero))
                node->mergeFlags(NodeMayNegZeroInBaseline);
            if (resultProfile.didObserveNonInt32())
                node->mergeFlags(NodeMayHaveNonIntResult);
            break;
        }

        default:
            RELEASE_ASSERT_NOT_REACHED();
            break;
        }
        
        return node;
    }
    
    Node* makeDivSafe(Node* node)
    {
        ASSERT(node->op() == ArithDiv);
        
        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, Overflow))
            node->mergeFlags(NodeMayOverflowInt32InDFG);
        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, NegativeZero))
            node->mergeFlags(NodeMayNegZeroInDFG);
        
        // The main slow case counter for op_div in the old JIT counts only when
        // the operands are not numbers. We don't care about that since we already
        // have speculations in place that take care of that separately. We only
        // care about when the outcome of the division is not an integer, which
        // is what the special fast case counter tells us.
        
        if (!m_inlineStackTop->m_profiledBlock->couldTakeSpecialFastCase(m_currentIndex))
            return node;
        
        // FIXME: It might be possible to make this more granular.
        node->mergeFlags(NodeMayOverflowInt32InBaseline | NodeMayNegZeroInBaseline);
        
        return node;
    }
    
    void noticeArgumentsUse()
    {
        // All of the arguments in this function need to be formatted as JSValues because we will
        // load from them in a random-access fashion and we don't want to have to switch on
        // format.
        
        for (ArgumentPosition* argument : m_inlineStackTop->m_argumentPositions)
            argument->mergeShouldNeverUnbox(true);
    }

    bool needsDynamicLookup(ResolveType, OpcodeID);
    
    VM* m_vm;
    CodeBlock* m_codeBlock;
    CodeBlock* m_profiledBlock;
    Graph& m_graph;

    // The current block being generated.
    BasicBlock* m_currentBlock;
    // The bytecode index of the current instruction being generated.
    unsigned m_currentIndex;
    // The semantic origin of the current node if different from the current Index.
    CodeOrigin m_currentSemanticOrigin;
    // True if it's OK to OSR exit right now.
    bool m_exitOK { false };

    FrozenValue* m_constantUndefined;
    FrozenValue* m_constantNull;
    FrozenValue* m_constantNaN;
    FrozenValue* m_constantOne;
    Vector<Node*, 16> m_constants;

    // The number of arguments passed to the function.
    unsigned m_numArguments;
    // The number of locals (vars + temporaries) used in the function.
    unsigned m_numLocals;
    // The number of slots (in units of sizeof(Register)) that we need to
    // preallocate for arguments to outgoing calls from this frame. This
    // number includes the CallFrame slots that we initialize for the callee
    // (but not the callee-initialized CallerFrame and ReturnPC slots).
    // This number is 0 if and only if this function is a leaf.
    unsigned m_parameterSlots;
    // The number of var args passed to the next var arg node.
    unsigned m_numPassedVarArgs;

    HashMap<ConstantBufferKey, unsigned> m_constantBufferCache;
    
    struct InlineStackEntry {
        ByteCodeParser* m_byteCodeParser;
        
        CodeBlock* m_codeBlock;
        CodeBlock* m_profiledBlock;
        InlineCallFrame* m_inlineCallFrame;
        
        ScriptExecutable* executable() { return m_codeBlock->ownerScriptExecutable(); }
        
        QueryableExitProfile m_exitProfile;
        
        // Remapping of identifier and constant numbers from the code block being
        // inlined (inline callee) to the code block that we're inlining into
        // (the machine code block, which is the transitive, though not necessarily
        // direct, caller).
        Vector<unsigned> m_identifierRemap;
        Vector<unsigned> m_constantBufferRemap;
        Vector<unsigned> m_switchRemap;
        
        // Blocks introduced by this code block, which need successor linking.
        // May include up to one basic block that includes the continuation after
        // the callsite in the caller. These must be appended in the order that they
        // are created, but their bytecodeBegin values need not be in order as they
        // are ignored.
        Vector<UnlinkedBlock> m_unlinkedBlocks;
        
        // Potential block linking targets. Must be sorted by bytecodeBegin, and
        // cannot have two blocks that have the same bytecodeBegin.
        Vector<BasicBlock*> m_blockLinkingTargets;
        
        // If the callsite's basic block was split into two, then this will be
        // the head of the callsite block. It needs its successors linked to the
        // m_unlinkedBlocks, but not the other way around: there's no way for
        // any blocks in m_unlinkedBlocks to jump back into this block.
        BasicBlock* m_callsiteBlockHead;
        
        // Does the callsite block head need linking? This is typically true
        // but will be false for the machine code block's inline stack entry
        // (since that one is not inlined) and for cases where an inline callee
        // did the linking for us.
        bool m_callsiteBlockHeadNeedsLinking;
        
        VirtualRegister m_returnValue;
        
        // Speculations about variable types collected from the profiled code block,
        // which are based on OSR exit profiles that past DFG compilatins of this
        // code block had gathered.
        LazyOperandValueProfileParser m_lazyOperands;
        
        CallLinkInfoMap m_callLinkInfos;
        StubInfoMap m_stubInfos;
        ByValInfoMap m_byValInfos;
        
        // Did we see any returns? We need to handle the (uncommon but necessary)
        // case where a procedure that does not return was inlined.
        bool m_didReturn;
        
        // Did we have any early returns?
        bool m_didEarlyReturn;
        
        // Pointers to the argument position trackers for this slice of code.
        Vector<ArgumentPosition*> m_argumentPositions;
        
        InlineStackEntry* m_caller;
        
        InlineStackEntry(
            ByteCodeParser*,
            CodeBlock*,
            CodeBlock* profiledBlock,
            BasicBlock* callsiteBlockHead,
            JSFunction* callee, // Null if this is a closure call.
            VirtualRegister returnValueVR,
            VirtualRegister inlineCallFrameStart,
            int argumentCountIncludingThis,
            InlineCallFrame::Kind);
        
        ~InlineStackEntry()
        {
            m_byteCodeParser->m_inlineStackTop = m_caller;
        }
        
        VirtualRegister remapOperand(VirtualRegister operand) const
        {
            if (!m_inlineCallFrame)
                return operand;
            
            ASSERT(!operand.isConstant());

            return VirtualRegister(operand.offset() + m_inlineCallFrame->stackOffset);
        }
    };
    
    InlineStackEntry* m_inlineStackTop;
    
    struct DelayedSetLocal {
        CodeOrigin m_origin;
        VirtualRegister m_operand;
        Node* m_value;
        
        DelayedSetLocal() { }
        DelayedSetLocal(const CodeOrigin& origin, VirtualRegister operand, Node* value)
            : m_origin(origin)
            , m_operand(operand)
            , m_value(value)
        {
        }
        
        Node* execute(ByteCodeParser* parser, SetMode setMode = NormalSet)
        {
            if (m_operand.isArgument())
                return parser->setArgument(m_origin, m_operand, m_value, setMode);
            return parser->setLocal(m_origin, m_operand, m_value, setMode);
        }
    };
    
    Vector<DelayedSetLocal, 2> m_setLocalQueue;

    CodeBlock* m_dfgCodeBlock;
    CallLinkStatus::ContextMap m_callContextMap;
    StubInfoMap m_dfgStubInfos;
    
    Instruction* m_currentInstruction;
    bool m_hasDebuggerEnabled;
};

#define NEXT_OPCODE(name) \
    m_currentIndex += OPCODE_LENGTH(name); \
    continue

#define LAST_OPCODE(name) \
    m_currentIndex += OPCODE_LENGTH(name); \
    m_exitOK = false; \
    return shouldContinueParsing

ByteCodeParser::Terminality ByteCodeParser::handleCall(Instruction* pc, NodeType op, CallMode callMode)
{
    ASSERT(OPCODE_LENGTH(op_call) == OPCODE_LENGTH(op_construct));
    ASSERT(OPCODE_LENGTH(op_call) == OPCODE_LENGTH(op_tail_call));
    return handleCall(
        pc[1].u.operand, op, callMode, OPCODE_LENGTH(op_call),
        pc[2].u.operand, pc[3].u.operand, -pc[4].u.operand);
}

ByteCodeParser::Terminality ByteCodeParser::handleCall(
    int result, NodeType op, CallMode callMode, unsigned instructionSize,
    int callee, int argumentCountIncludingThis, int registerOffset)
{
    Node* callTarget = get(VirtualRegister(callee));
    
    CallLinkStatus callLinkStatus = CallLinkStatus::computeFor(
        m_inlineStackTop->m_profiledBlock, currentCodeOrigin(),
        m_inlineStackTop->m_callLinkInfos, m_callContextMap);
    
    return handleCall(
        result, op, callMode, instructionSize, callTarget,
        argumentCountIncludingThis, registerOffset, callLinkStatus);
}
    
ByteCodeParser::Terminality ByteCodeParser::handleCall(
    int result, NodeType op, CallMode callMode, unsigned instructionSize,
    Node* callTarget, int argumentCountIncludingThis, int registerOffset,
    CallLinkStatus callLinkStatus)
{
    return handleCall(
        result, op, InlineCallFrame::kindFor(callMode), instructionSize, callTarget, argumentCountIncludingThis,
        registerOffset, callLinkStatus, getPrediction());
}

void ByteCodeParser::refineStatically(CallLinkStatus& callLinkStatus, Node* callTarget)
{
    if (callTarget->isCellConstant()) {
        callLinkStatus.setProvenConstantCallee(CallVariant(callTarget->asCell()));
        return;
    }
}

ByteCodeParser::Terminality ByteCodeParser::handleCall(
    int result, NodeType op, InlineCallFrame::Kind kind, unsigned instructionSize,
    Node* callTarget, int argumentCountIncludingThis, int registerOffset,
    CallLinkStatus callLinkStatus, SpeculatedType prediction)
{
    ASSERT(registerOffset <= 0);

    refineStatically(callLinkStatus, callTarget);
    
    if (Options::verboseDFGByteCodeParsing())
        dataLog("    Handling call at ", currentCodeOrigin(), ": ", callLinkStatus, "\n");
    
    if (!callLinkStatus.canOptimize()) {
        // Oddly, this conflates calls that haven't executed with calls that behaved sufficiently polymorphically
        // that we cannot optimize them.

        Node* callNode = addCall(result, op, OpInfo(), callTarget, argumentCountIncludingThis, registerOffset, prediction);
        if (callNode->op() == TailCall)
            return Terminal;
        ASSERT(callNode->op() != TailCallVarargs);
        return NonTerminal;
    }
    
    unsigned nextOffset = m_currentIndex + instructionSize;
    
    OpInfo callOpInfo;
    
    if (handleInlining(callTarget, result, callLinkStatus, registerOffset, virtualRegisterForArgument(0, registerOffset), VirtualRegister(), 0, argumentCountIncludingThis, nextOffset, op, kind, prediction)) {
        if (m_graph.compilation())
            m_graph.compilation()->noticeInlinedCall();
        return NonTerminal;
    }
    
    Node* callNode = addCall(result, op, callOpInfo, callTarget, argumentCountIncludingThis, registerOffset, prediction);
    if (callNode->op() == TailCall)
        return Terminal;
    ASSERT(callNode->op() != TailCallVarargs);
    return NonTerminal;
}

ByteCodeParser::Terminality ByteCodeParser::handleVarargsCall(Instruction* pc, NodeType op, CallMode callMode)
{
    ASSERT(OPCODE_LENGTH(op_call_varargs) == OPCODE_LENGTH(op_construct_varargs));
    ASSERT(OPCODE_LENGTH(op_call_varargs) == OPCODE_LENGTH(op_tail_call_varargs));
    
    int result = pc[1].u.operand;
    int callee = pc[2].u.operand;
    int thisReg = pc[3].u.operand;
    int arguments = pc[4].u.operand;
    int firstFreeReg = pc[5].u.operand;
    int firstVarArgOffset = pc[6].u.operand;
    
    SpeculatedType prediction = getPrediction();
    
    Node* callTarget = get(VirtualRegister(callee));
    
    CallLinkStatus callLinkStatus = CallLinkStatus::computeFor(
        m_inlineStackTop->m_profiledBlock, currentCodeOrigin(),
        m_inlineStackTop->m_callLinkInfos, m_callContextMap);
    refineStatically(callLinkStatus, callTarget);
    
    if (Options::verboseDFGByteCodeParsing())
        dataLog("    Varargs call link status at ", currentCodeOrigin(), ": ", callLinkStatus, "\n");
    
    if (callLinkStatus.canOptimize()
        && handleInlining(callTarget, result, callLinkStatus, firstFreeReg, VirtualRegister(thisReg), VirtualRegister(arguments), firstVarArgOffset, 0, m_currentIndex + OPCODE_LENGTH(op_call_varargs), op, InlineCallFrame::varargsKindFor(callMode), prediction)) {
        if (m_graph.compilation())
            m_graph.compilation()->noticeInlinedCall();
        return NonTerminal;
    }
    
    CallVarargsData* data = m_graph.m_callVarargsData.add();
    data->firstVarArgOffset = firstVarArgOffset;
    
    Node* thisChild = get(VirtualRegister(thisReg));

    if (op == TailCallVarargs) {
        if (allInlineFramesAreTailCalls()) {
            addToGraph(op, OpInfo(data), OpInfo(), callTarget, get(VirtualRegister(arguments)), thisChild);
            return Terminal;
        }
        op = TailCallVarargsInlinedCaller;
    }

    Node* call = addToGraph(op, OpInfo(data), OpInfo(prediction), callTarget, get(VirtualRegister(arguments)), thisChild);
    VirtualRegister resultReg(result);
    if (resultReg.isValid())
        set(resultReg, call);
    return NonTerminal;
}

void ByteCodeParser::emitFunctionChecks(CallVariant callee, Node* callTarget, VirtualRegister thisArgumentReg)
{
    Node* thisArgument;
    if (thisArgumentReg.isValid())
        thisArgument = get(thisArgumentReg);
    else
        thisArgument = 0;

    JSCell* calleeCell;
    Node* callTargetForCheck;
    if (callee.isClosureCall()) {
        calleeCell = callee.executable();
        callTargetForCheck = addToGraph(GetExecutable, callTarget);
    } else {
        calleeCell = callee.nonExecutableCallee();
        callTargetForCheck = callTarget;
    }
    
    ASSERT(calleeCell);
    addToGraph(CheckCell, OpInfo(m_graph.freeze(calleeCell)), callTargetForCheck, thisArgument);
}

void ByteCodeParser::emitArgumentPhantoms(int registerOffset, int argumentCountIncludingThis)
{
    for (int i = 0; i < argumentCountIncludingThis; ++i)
        addToGraph(Phantom, get(virtualRegisterForArgument(i, registerOffset)));
}

unsigned ByteCodeParser::inliningCost(CallVariant callee, int argumentCountIncludingThis, CallMode callMode)
{
    CodeSpecializationKind kind = specializationKindFor(callMode);
    if (verbose)
        dataLog("Considering inlining ", callee, " into ", currentCodeOrigin(), "\n");
    
    if (m_hasDebuggerEnabled) {
        if (verbose)
            dataLog("    Failing because the debugger is in use.\n");
        return UINT_MAX;
    }

    FunctionExecutable* executable = callee.functionExecutable();
    if (!executable) {
        if (verbose)
            dataLog("    Failing because there is no function executable.\n");
        return UINT_MAX;
    }
    
    // Does the number of arguments we're passing match the arity of the target? We currently
    // inline only if the number of arguments passed is greater than or equal to the number
    // arguments expected.
    if (static_cast<int>(executable->parameterCount()) + 1 > argumentCountIncludingThis) {
        if (verbose)
            dataLog("    Failing because of arity mismatch.\n");
        return UINT_MAX;
    }
    
    // Do we have a code block, and does the code block's size match the heuristics/requirements for
    // being an inline candidate? We might not have a code block (1) if code was thrown away,
    // (2) if we simply hadn't actually made this call yet or (3) code is a builtin function and
    // specialization kind is construct. In the former 2 cases, we could still theoretically attempt
    // to inline it if we had a static proof of what was being called; this might happen for example
    // if you call a global function, where watchpointing gives us static information. Overall,
    // it's a rare case because we expect that any hot callees would have already been compiled.
    CodeBlock* codeBlock = executable->baselineCodeBlockFor(kind);
    if (!codeBlock) {
        if (verbose)
            dataLog("    Failing because no code block available.\n");
        return UINT_MAX;
    }
    CapabilityLevel capabilityLevel = inlineFunctionForCapabilityLevel(
        codeBlock, kind, callee.isClosureCall());
    if (verbose) {
        dataLog("    Call mode: ", callMode, "\n");
        dataLog("    Is closure call: ", callee.isClosureCall(), "\n");
        dataLog("    Capability level: ", capabilityLevel, "\n");
        dataLog("    Might inline function: ", mightInlineFunctionFor(codeBlock, kind), "\n");
        dataLog("    Might compile function: ", mightCompileFunctionFor(codeBlock, kind), "\n");
        dataLog("    Is supported for inlining: ", isSupportedForInlining(codeBlock), "\n");
        dataLog("    Is inlining candidate: ", codeBlock->ownerScriptExecutable()->isInliningCandidate(), "\n");
    }
    if (!canInline(capabilityLevel)) {
        if (verbose)
            dataLog("    Failing because the function is not inlineable.\n");
        return UINT_MAX;
    }
    
    // Check if the caller is already too large. We do this check here because that's just
    // where we happen to also have the callee's code block, and we want that for the
    // purpose of unsetting SABI.
    if (!isSmallEnoughToInlineCodeInto(m_codeBlock)) {
        codeBlock->m_shouldAlwaysBeInlined = false;
        if (verbose)
            dataLog("    Failing because the caller is too large.\n");
        return UINT_MAX;
    }
    
    // FIXME: this should be better at predicting how much bloat we will introduce by inlining
    // this function.
    // https://bugs.webkit.org/show_bug.cgi?id=127627
    
    // FIXME: We currently inline functions that have run in LLInt but not in Baseline. These
    // functions have very low fidelity profiling, and presumably they weren't very hot if they
    // haven't gotten to Baseline yet. Consider not inlining these functions.
    // https://bugs.webkit.org/show_bug.cgi?id=145503
    
    // Have we exceeded inline stack depth, or are we trying to inline a recursive call to
    // too many levels? If either of these are detected, then don't inline. We adjust our
    // heuristics if we are dealing with a function that cannot otherwise be compiled.
    
    unsigned depth = 0;
    unsigned recursion = 0;
    
    for (InlineStackEntry* entry = m_inlineStackTop; entry; entry = entry->m_caller) {
        ++depth;
        if (depth >= Options::maximumInliningDepth()) {
            if (verbose)
                dataLog("    Failing because depth exceeded.\n");
            return UINT_MAX;
        }
        
        if (entry->executable() == executable) {
            ++recursion;
            if (recursion >= Options::maximumInliningRecursion()) {
                if (verbose)
                    dataLog("    Failing because recursion detected.\n");
                return UINT_MAX;
            }
        }
    }
    
    if (verbose)
        dataLog("    Inlining should be possible.\n");
    
    // It might be possible to inline.
    return codeBlock->instructionCount();
}

template<typename ChecksFunctor>
void ByteCodeParser::inlineCall(Node* callTargetNode, int resultOperand, CallVariant callee, int registerOffset, int argumentCountIncludingThis, unsigned nextOffset, InlineCallFrame::Kind kind, CallerLinkability callerLinkability, const ChecksFunctor& insertChecks)
{
    CodeSpecializationKind specializationKind = InlineCallFrame::specializationKindFor(kind);
    
    ASSERT(inliningCost(callee, argumentCountIncludingThis, InlineCallFrame::callModeFor(kind)) != UINT_MAX);
    
    CodeBlock* codeBlock = callee.functionExecutable()->baselineCodeBlockFor(specializationKind);
    insertChecks(codeBlock);

    // FIXME: Don't flush constants!
    
    int inlineCallFrameStart = m_inlineStackTop->remapOperand(VirtualRegister(registerOffset)).offset() + JSStack::CallFrameHeaderSize;
    
    ensureLocals(
        VirtualRegister(inlineCallFrameStart).toLocal() + 1 +
        JSStack::CallFrameHeaderSize + codeBlock->m_numCalleeLocals);
    
    size_t argumentPositionStart = m_graph.m_argumentPositions.size();

    VirtualRegister resultReg(resultOperand);
    if (resultReg.isValid())
        resultReg = m_inlineStackTop->remapOperand(resultReg);

    VariableAccessData* calleeVariable = nullptr;
    if (callee.isClosureCall()) {
        Node* calleeSet = set(
            VirtualRegister(registerOffset + JSStack::Callee), callTargetNode, ImmediateNakedSet);
        
        calleeVariable = calleeSet->variableAccessData();
        calleeVariable->mergeShouldNeverUnbox(true);
    }
    
    InlineStackEntry inlineStackEntry(
        this, codeBlock, codeBlock, m_graph.lastBlock(), callee.function(), resultReg,
        (VirtualRegister)inlineCallFrameStart, argumentCountIncludingThis, kind);
    
    // This is where the actual inlining really happens.
    unsigned oldIndex = m_currentIndex;
    m_currentIndex = 0;

    // At this point, it's again OK to OSR exit.
    m_exitOK = true;

    InlineVariableData inlineVariableData;
    inlineVariableData.inlineCallFrame = m_inlineStackTop->m_inlineCallFrame;
    inlineVariableData.argumentPositionStart = argumentPositionStart;
    inlineVariableData.calleeVariable = 0;
    
    RELEASE_ASSERT(
        m_inlineStackTop->m_inlineCallFrame->isClosureCall
        == callee.isClosureCall());
    if (callee.isClosureCall()) {
        RELEASE_ASSERT(calleeVariable);
        inlineVariableData.calleeVariable = calleeVariable;
    }
    
    m_graph.m_inlineVariableData.append(inlineVariableData);

    parseCodeBlock();
    clearCaches(); // Reset our state now that we're back to the outer code.
    
    m_currentIndex = oldIndex;
    m_exitOK = false;
    
    // If the inlined code created some new basic blocks, then we have linking to do.
    if (inlineStackEntry.m_callsiteBlockHead != m_graph.lastBlock()) {
        
        ASSERT(!inlineStackEntry.m_unlinkedBlocks.isEmpty());
        if (inlineStackEntry.m_callsiteBlockHeadNeedsLinking)
            linkBlock(inlineStackEntry.m_callsiteBlockHead, inlineStackEntry.m_blockLinkingTargets);
        else
            ASSERT(inlineStackEntry.m_callsiteBlockHead->isLinked);
        
        if (callerLinkability == CallerDoesNormalLinking)
            cancelLinkingForBlock(inlineStackEntry.m_caller, inlineStackEntry.m_callsiteBlockHead);
        
        linkBlocks(inlineStackEntry.m_unlinkedBlocks, inlineStackEntry.m_blockLinkingTargets);
    } else
        ASSERT(inlineStackEntry.m_unlinkedBlocks.isEmpty());
    
    BasicBlock* lastBlock = m_graph.lastBlock();
    // If there was a return, but no early returns, then we're done. We allow parsing of
    // the caller to continue in whatever basic block we're in right now.
    if (!inlineStackEntry.m_didEarlyReturn && inlineStackEntry.m_didReturn) {
        if (Options::verboseDFGByteCodeParsing())
            dataLog("    Allowing parsing to continue in last inlined block.\n");
        
        ASSERT(lastBlock->isEmpty() || !lastBlock->terminal());
        
        // If we created new blocks then the last block needs linking, but in the
        // caller. It doesn't need to be linked to, but it needs outgoing links.
        if (!inlineStackEntry.m_unlinkedBlocks.isEmpty()) {
            // For debugging purposes, set the bytecodeBegin. Note that this doesn't matter
            // for release builds because this block will never serve as a potential target
            // in the linker's binary search.
            if (Options::verboseDFGByteCodeParsing())
                dataLog("        Repurposing last block from ", lastBlock->bytecodeBegin, " to ", m_currentIndex, "\n");
            lastBlock->bytecodeBegin = m_currentIndex;
            if (callerLinkability == CallerDoesNormalLinking) {
                if (verbose)
                    dataLog("Adding unlinked block ", RawPointer(m_graph.lastBlock()), " (one return)\n");
                m_inlineStackTop->m_caller->m_unlinkedBlocks.append(UnlinkedBlock(m_graph.lastBlock()));
            }
        }
        
        m_currentBlock = m_graph.lastBlock();
        return;
    }

    if (Options::verboseDFGByteCodeParsing())
        dataLog("    Creating new block after inlining.\n");

    // If we get to this point then all blocks must end in some sort of terminals.
    ASSERT(lastBlock->terminal());

    // Need to create a new basic block for the continuation at the caller.
    RefPtr<BasicBlock> block = adoptRef(new BasicBlock(nextOffset, m_numArguments, m_numLocals, 1));

    // Link the early returns to the basic block we're about to create.
    for (size_t i = 0; i < inlineStackEntry.m_unlinkedBlocks.size(); ++i) {
        if (!inlineStackEntry.m_unlinkedBlocks[i].m_needsEarlyReturnLinking)
            continue;
        BasicBlock* blockToLink = inlineStackEntry.m_unlinkedBlocks[i].m_block;
        ASSERT(!blockToLink->isLinked);
        Node* node = blockToLink->terminal();
        ASSERT(node->op() == Jump);
        ASSERT(!node->targetBlock());
        node->targetBlock() = block.get();
        inlineStackEntry.m_unlinkedBlocks[i].m_needsEarlyReturnLinking = false;
        if (verbose)
            dataLog("Marking ", RawPointer(blockToLink), " as linked (jumps to return)\n");
        blockToLink->didLink();
    }
    
    m_currentBlock = block.get();
    ASSERT(m_inlineStackTop->m_caller->m_blockLinkingTargets.isEmpty() || m_inlineStackTop->m_caller->m_blockLinkingTargets.last()->bytecodeBegin < nextOffset);
    if (verbose)
        dataLog("Adding unlinked block ", RawPointer(block.get()), " (many returns)\n");
    if (callerLinkability == CallerDoesNormalLinking) {
        m_inlineStackTop->m_caller->m_unlinkedBlocks.append(UnlinkedBlock(block.get()));
        m_inlineStackTop->m_caller->m_blockLinkingTargets.append(block.get());
    }
    m_graph.appendBlock(block);
    prepareToParseBlock();
}

void ByteCodeParser::cancelLinkingForBlock(InlineStackEntry* inlineStackEntry, BasicBlock* block)
{
    // It's possible that the callsite block head is not owned by the caller.
    if (!inlineStackEntry->m_unlinkedBlocks.isEmpty()) {
        // It's definitely owned by the caller, because the caller created new blocks.
        // Assert that this all adds up.
        ASSERT_UNUSED(block, inlineStackEntry->m_unlinkedBlocks.last().m_block == block);
        ASSERT(inlineStackEntry->m_unlinkedBlocks.last().m_needsNormalLinking);
        inlineStackEntry->m_unlinkedBlocks.last().m_needsNormalLinking = false;
    } else {
        // It's definitely not owned by the caller. Tell the caller that he does not
        // need to link his callsite block head, because we did it for him.
        ASSERT(inlineStackEntry->m_callsiteBlockHeadNeedsLinking);
        ASSERT_UNUSED(block, inlineStackEntry->m_callsiteBlockHead == block);
        inlineStackEntry->m_callsiteBlockHeadNeedsLinking = false;
    }
}

template<typename ChecksFunctor>
bool ByteCodeParser::attemptToInlineCall(Node* callTargetNode, int resultOperand, CallVariant callee, int registerOffset, int argumentCountIncludingThis, unsigned nextOffset, InlineCallFrame::Kind kind, CallerLinkability callerLinkability, SpeculatedType prediction, unsigned& inliningBalance, const ChecksFunctor& insertChecks)
{
    CodeSpecializationKind specializationKind = InlineCallFrame::specializationKindFor(kind);
    
    if (!inliningBalance)
        return false;
    
    if (verbose)
        dataLog("    Considering callee ", callee, "\n");
    
    // Intrinsics and internal functions can only be inlined if we're not doing varargs. This is because
    // we currently don't have any way of getting profiling information for arguments to non-JS varargs
    // calls. The prediction propagator won't be of any help because LoadVarargs obscures the data flow,
    // and there are no callsite value profiles and native function won't have callee value profiles for
    // those arguments. Even worse, if the intrinsic decides to exit, it won't really have anywhere to
    // exit to: LoadVarargs is effectful and it's part of the op_call_varargs, so we can't exit without
    // calling LoadVarargs twice.
    if (!InlineCallFrame::isVarargs(kind)) {

        bool didInsertChecks = false;
        auto insertChecksWithAccounting = [&] () {
            insertChecks(nullptr);
            didInsertChecks = true;
        };
    
        if (InternalFunction* function = callee.internalFunction()) {
            if (handleConstantInternalFunction(callTargetNode, resultOperand, function, registerOffset, argumentCountIncludingThis, specializationKind, insertChecksWithAccounting)) {
                RELEASE_ASSERT(didInsertChecks);
                addToGraph(Phantom, callTargetNode);
                emitArgumentPhantoms(registerOffset, argumentCountIncludingThis);
                inliningBalance--;
                return true;
            }
            RELEASE_ASSERT(!didInsertChecks);
            return false;
        }
    
        Intrinsic intrinsic = callee.intrinsicFor(specializationKind);
        if (intrinsic != NoIntrinsic) {
            if (handleIntrinsicCall(callTargetNode, resultOperand, intrinsic, registerOffset, argumentCountIncludingThis, prediction, insertChecksWithAccounting)) {
                RELEASE_ASSERT(didInsertChecks);
                addToGraph(Phantom, callTargetNode);
                emitArgumentPhantoms(registerOffset, argumentCountIncludingThis);
                inliningBalance--;
                return true;
            }

            RELEASE_ASSERT(!didInsertChecks);
            // We might still try to inline the Intrinsic because it might be a builtin JS function.
        }
    }
    
    unsigned myInliningCost = inliningCost(callee, argumentCountIncludingThis, InlineCallFrame::callModeFor(kind));
    if (myInliningCost > inliningBalance)
        return false;

    Instruction* savedCurrentInstruction = m_currentInstruction;
    inlineCall(callTargetNode, resultOperand, callee, registerOffset, argumentCountIncludingThis, nextOffset, kind, callerLinkability, insertChecks);
    inliningBalance -= myInliningCost;
    m_currentInstruction = savedCurrentInstruction;
    return true;
}

bool ByteCodeParser::handleInlining(
    Node* callTargetNode, int resultOperand, const CallLinkStatus& callLinkStatus,
    int registerOffsetOrFirstFreeReg, VirtualRegister thisArgument,
    VirtualRegister argumentsArgument, unsigned argumentsOffset, int argumentCountIncludingThis,
    unsigned nextOffset, NodeType callOp, InlineCallFrame::Kind kind, SpeculatedType prediction)
{
    if (verbose) {
        dataLog("Handling inlining...\n");
        dataLog("Stack: ", currentCodeOrigin(), "\n");
    }
    CodeSpecializationKind specializationKind = InlineCallFrame::specializationKindFor(kind);
    
    if (!callLinkStatus.size()) {
        if (verbose)
            dataLog("Bailing inlining.\n");
        return false;
    }
    
    if (InlineCallFrame::isVarargs(kind)
        && callLinkStatus.maxNumArguments() > Options::maximumVarargsForInlining()) {
        if (verbose)
            dataLog("Bailing inlining because of varargs.\n");
        return false;
    }
        
    unsigned inliningBalance = Options::maximumFunctionForCallInlineCandidateInstructionCount();
    if (specializationKind == CodeForConstruct)
        inliningBalance = std::min(inliningBalance, Options::maximumFunctionForConstructInlineCandidateInstructionCount());
    if (callLinkStatus.isClosureCall())
        inliningBalance = std::min(inliningBalance, Options::maximumFunctionForClosureCallInlineCandidateInstructionCount());
    
    // First check if we can avoid creating control flow. Our inliner does some CFG
    // simplification on the fly and this helps reduce compile times, but we can only leverage
    // this in cases where we don't need control flow diamonds to check the callee.
    if (!callLinkStatus.couldTakeSlowPath() && callLinkStatus.size() == 1) {
        int registerOffset;
        
        // Only used for varargs calls.
        unsigned mandatoryMinimum = 0;
        unsigned maxNumArguments = 0;

        if (InlineCallFrame::isVarargs(kind)) {
            if (FunctionExecutable* functionExecutable = callLinkStatus[0].functionExecutable())
                mandatoryMinimum = functionExecutable->parameterCount();
            else
                mandatoryMinimum = 0;
            
            // includes "this"
            maxNumArguments = std::max(
                callLinkStatus.maxNumArguments(),
                mandatoryMinimum + 1);
            
            // We sort of pretend that this *is* the number of arguments that were passed.
            argumentCountIncludingThis = maxNumArguments;
            
            registerOffset = registerOffsetOrFirstFreeReg + 1;
            registerOffset -= maxNumArguments; // includes "this"
            registerOffset -= JSStack::CallFrameHeaderSize;
            registerOffset = -WTF::roundUpToMultipleOf(
                stackAlignmentRegisters(),
                -registerOffset);
        } else
            registerOffset = registerOffsetOrFirstFreeReg;
        
        bool result = attemptToInlineCall(
            callTargetNode, resultOperand, callLinkStatus[0], registerOffset,
            argumentCountIncludingThis, nextOffset, kind, CallerDoesNormalLinking, prediction,
            inliningBalance, [&] (CodeBlock* codeBlock) {
                emitFunctionChecks(callLinkStatus[0], callTargetNode, thisArgument);

                // If we have a varargs call, we want to extract the arguments right now.
                if (InlineCallFrame::isVarargs(kind)) {
                    int remappedRegisterOffset =
                        m_inlineStackTop->remapOperand(VirtualRegister(registerOffset)).offset();
                    
                    ensureLocals(VirtualRegister(remappedRegisterOffset).toLocal());
                    
                    int argumentStart = registerOffset + JSStack::CallFrameHeaderSize;
                    int remappedArgumentStart =
                        m_inlineStackTop->remapOperand(VirtualRegister(argumentStart)).offset();

                    LoadVarargsData* data = m_graph.m_loadVarargsData.add();
                    data->start = VirtualRegister(remappedArgumentStart + 1);
                    data->count = VirtualRegister(remappedRegisterOffset + JSStack::ArgumentCount);
                    data->offset = argumentsOffset;
                    data->limit = maxNumArguments;
                    data->mandatoryMinimum = mandatoryMinimum;
            
                    addToGraph(LoadVarargs, OpInfo(data), get(argumentsArgument));

                    // LoadVarargs may OSR exit. Hence, we need to keep alive callTargetNode, thisArgument
                    // and argumentsArgument for the baseline JIT. However, we only need a Phantom for
                    // callTargetNode because the other 2 are still in use and alive at this point.
                    addToGraph(Phantom, callTargetNode);

                    // In DFG IR before SSA, we cannot insert control flow between after the
                    // LoadVarargs and the last SetArgument. This isn't a problem once we get to DFG
                    // SSA. Fortunately, we also have other reasons for not inserting control flow
                    // before SSA.
            
                    VariableAccessData* countVariable = newVariableAccessData(
                        VirtualRegister(remappedRegisterOffset + JSStack::ArgumentCount));
                    // This is pretty lame, but it will force the count to be flushed as an int. This doesn't
                    // matter very much, since our use of a SetArgument and Flushes for this local slot is
                    // mostly just a formality.
                    countVariable->predict(SpecInt32);
                    countVariable->mergeIsProfitableToUnbox(true);
                    Node* setArgumentCount = addToGraph(SetArgument, OpInfo(countVariable));
                    m_currentBlock->variablesAtTail.setOperand(countVariable->local(), setArgumentCount);

                    set(VirtualRegister(argumentStart), get(thisArgument), ImmediateNakedSet);
                    for (unsigned argument = 1; argument < maxNumArguments; ++argument) {
                        VariableAccessData* variable = newVariableAccessData(
                            VirtualRegister(remappedArgumentStart + argument));
                        variable->mergeShouldNeverUnbox(true); // We currently have nowhere to put the type check on the LoadVarargs. LoadVarargs is effectful, so after it finishes, we cannot exit.
                        
                        // For a while it had been my intention to do things like this inside the
                        // prediction injection phase. But in this case it's really best to do it here,
                        // because it's here that we have access to the variable access datas for the
                        // inlining we're about to do.
                        //
                        // Something else that's interesting here is that we'd really love to get
                        // predictions from the arguments loaded at the callsite, rather than the
                        // arguments received inside the callee. But that probably won't matter for most
                        // calls.
                        if (codeBlock && argument < static_cast<unsigned>(codeBlock->numParameters())) {
                            ConcurrentJITLocker locker(codeBlock->m_lock);
                            if (ValueProfile* profile = codeBlock->valueProfileForArgument(argument))
                                variable->predict(profile->computeUpdatedPrediction(locker));
                        }
                        
                        Node* setArgument = addToGraph(SetArgument, OpInfo(variable));
                        m_currentBlock->variablesAtTail.setOperand(variable->local(), setArgument);
                    }
                }
            });
        if (verbose) {
            dataLog("Done inlining (simple).\n");
            dataLog("Stack: ", currentCodeOrigin(), "\n");
            dataLog("Result: ", result, "\n");
        }
        return result;
    }
    
    // We need to create some kind of switch over callee. For now we only do this if we believe that
    // we're in the top tier. We have two reasons for this: first, it provides us an opportunity to
    // do more detailed polyvariant/polymorphic profiling; and second, it reduces compile times in
    // the DFG. And by polyvariant profiling we mean polyvariant profiling of *this* call. Note that
    // we could improve that aspect of this by doing polymorphic inlining but having the profiling
    // also.
    if (!isFTL(m_graph.m_plan.mode) || !Options::usePolymorphicCallInlining()
        || InlineCallFrame::isVarargs(kind)) {
        if (verbose) {
            dataLog("Bailing inlining (hard).\n");
            dataLog("Stack: ", currentCodeOrigin(), "\n");
        }
        return false;
    }
    
    // If the claim is that this did not originate from a stub, then we don't want to emit a switch
    // statement. Whenever the non-stub profiling says that it could take slow path, it really means that
    // it has no idea.
    if (!Options::usePolymorphicCallInliningForNonStubStatus()
        && !callLinkStatus.isBasedOnStub()) {
        if (verbose) {
            dataLog("Bailing inlining (non-stub polymorphism).\n");
            dataLog("Stack: ", currentCodeOrigin(), "\n");
        }
        return false;
    }
    
    unsigned oldOffset = m_currentIndex;
    
    bool allAreClosureCalls = true;
    bool allAreDirectCalls = true;
    for (unsigned i = callLinkStatus.size(); i--;) {
        if (callLinkStatus[i].isClosureCall())
            allAreDirectCalls = false;
        else
            allAreClosureCalls = false;
    }
    
    Node* thingToSwitchOn;
    if (allAreDirectCalls)
        thingToSwitchOn = callTargetNode;
    else if (allAreClosureCalls)
        thingToSwitchOn = addToGraph(GetExecutable, callTargetNode);
    else {
        // FIXME: We should be able to handle this case, but it's tricky and we don't know of cases
        // where it would be beneficial. It might be best to handle these cases as if all calls were
        // closure calls.
        // https://bugs.webkit.org/show_bug.cgi?id=136020
        if (verbose) {
            dataLog("Bailing inlining (mix).\n");
            dataLog("Stack: ", currentCodeOrigin(), "\n");
        }
        return false;
    }
    
    if (verbose) {
        dataLog("Doing hard inlining...\n");
        dataLog("Stack: ", currentCodeOrigin(), "\n");
    }
    
    int registerOffset = registerOffsetOrFirstFreeReg;
    
    // This makes me wish that we were in SSA all the time. We need to pick a variable into which to
    // store the callee so that it will be accessible to all of the blocks we're about to create. We
    // get away with doing an immediate-set here because we wouldn't have performed any side effects
    // yet.
    if (verbose)
        dataLog("Register offset: ", registerOffset);
    VirtualRegister calleeReg(registerOffset + JSStack::Callee);
    calleeReg = m_inlineStackTop->remapOperand(calleeReg);
    if (verbose)
        dataLog("Callee is going to be ", calleeReg, "\n");
    setDirect(calleeReg, callTargetNode, ImmediateSetWithFlush);

    // It's OK to exit right now, even though we set some locals. That's because those locals are not
    // user-visible.
    m_exitOK = true;
    addToGraph(ExitOK);
    
    SwitchData& data = *m_graph.m_switchData.add();
    data.kind = SwitchCell;
    addToGraph(Switch, OpInfo(&data), thingToSwitchOn);
    
    BasicBlock* originBlock = m_currentBlock;
    if (verbose)
        dataLog("Marking ", RawPointer(originBlock), " as linked (origin of poly inline)\n");
    originBlock->didLink();
    cancelLinkingForBlock(m_inlineStackTop, originBlock);
    
    // Each inlined callee will have a landing block that it returns at. They should all have jumps
    // to the continuation block, which we create last.
    Vector<BasicBlock*> landingBlocks;
    
    // We may force this true if we give up on inlining any of the edges.
    bool couldTakeSlowPath = callLinkStatus.couldTakeSlowPath();
    
    if (verbose)
        dataLog("About to loop over functions at ", currentCodeOrigin(), ".\n");
    
    for (unsigned i = 0; i < callLinkStatus.size(); ++i) {
        m_currentIndex = oldOffset;
        RefPtr<BasicBlock> block = adoptRef(new BasicBlock(UINT_MAX, m_numArguments, m_numLocals, 1));
        m_currentBlock = block.get();
        m_graph.appendBlock(block);
        prepareToParseBlock();
        
        Node* myCallTargetNode = getDirect(calleeReg);
        
        bool inliningResult = attemptToInlineCall(
            myCallTargetNode, resultOperand, callLinkStatus[i], registerOffset,
            argumentCountIncludingThis, nextOffset, kind, CallerLinksManually, prediction,
            inliningBalance, [&] (CodeBlock*) { });
        
        if (!inliningResult) {
            // That failed so we let the block die. Nothing interesting should have been added to
            // the block. We also give up on inlining any of the (less frequent) callees.
            ASSERT(m_currentBlock == block.get());
            ASSERT(m_graph.m_blocks.last() == block);
            m_graph.killBlockAndItsContents(block.get());
            m_graph.m_blocks.removeLast();
            
            // The fact that inlining failed means we need a slow path.
            couldTakeSlowPath = true;
            break;
        }
        
        JSCell* thingToCaseOn;
        if (allAreDirectCalls)
            thingToCaseOn = callLinkStatus[i].nonExecutableCallee();
        else {
            ASSERT(allAreClosureCalls);
            thingToCaseOn = callLinkStatus[i].executable();
        }
        data.cases.append(SwitchCase(m_graph.freeze(thingToCaseOn), block.get()));
        m_currentIndex = nextOffset;
        m_exitOK = true;
        processSetLocalQueue(); // This only comes into play for intrinsics, since normal inlined code will leave an empty queue.
        if (Node* terminal = m_currentBlock->terminal())
            ASSERT_UNUSED(terminal, terminal->op() == TailCall || terminal->op() == TailCallVarargs);
        else {
            addToGraph(Jump);
            landingBlocks.append(m_currentBlock);
        }
        if (verbose)
            dataLog("Marking ", RawPointer(m_currentBlock), " as linked (tail of poly inlinee)\n");
        m_currentBlock->didLink();

        if (verbose)
            dataLog("Finished inlining ", callLinkStatus[i], " at ", currentCodeOrigin(), ".\n");
    }
    
    RefPtr<BasicBlock> slowPathBlock = adoptRef(
        new BasicBlock(UINT_MAX, m_numArguments, m_numLocals, 1));
    m_currentIndex = oldOffset;
    m_exitOK = true;
    data.fallThrough = BranchTarget(slowPathBlock.get());
    m_graph.appendBlock(slowPathBlock);
    if (verbose)
        dataLog("Marking ", RawPointer(slowPathBlock.get()), " as linked (slow path block)\n");
    slowPathBlock->didLink();
    prepareToParseBlock();
    m_currentBlock = slowPathBlock.get();
    Node* myCallTargetNode = getDirect(calleeReg);
    if (couldTakeSlowPath) {
        addCall(
            resultOperand, callOp, OpInfo(), myCallTargetNode, argumentCountIncludingThis,
            registerOffset, prediction);
    } else {
        addToGraph(CheckBadCell);
        addToGraph(Phantom, myCallTargetNode);
        emitArgumentPhantoms(registerOffset, argumentCountIncludingThis);
        
        set(VirtualRegister(resultOperand), addToGraph(BottomValue));
    }

    m_currentIndex = nextOffset;
    m_exitOK = true; // Origin changed, so it's fine to exit again.
    processSetLocalQueue();
    if (Node* terminal = m_currentBlock->terminal())
        ASSERT_UNUSED(terminal, terminal->op() == TailCall || terminal->op() == TailCallVarargs);
    else {
        addToGraph(Jump);
        landingBlocks.append(m_currentBlock);
    }
    
    RefPtr<BasicBlock> continuationBlock = adoptRef(
        new BasicBlock(UINT_MAX, m_numArguments, m_numLocals, 1));
    m_graph.appendBlock(continuationBlock);
    if (verbose)
        dataLog("Adding unlinked block ", RawPointer(continuationBlock.get()), " (continuation)\n");
    m_inlineStackTop->m_unlinkedBlocks.append(UnlinkedBlock(continuationBlock.get()));
    prepareToParseBlock();
    m_currentBlock = continuationBlock.get();
    
    for (unsigned i = landingBlocks.size(); i--;)
        landingBlocks[i]->terminal()->targetBlock() = continuationBlock.get();
    
    m_currentIndex = oldOffset;
    m_exitOK = true;
    
    if (verbose) {
        dataLog("Done inlining (hard).\n");
        dataLog("Stack: ", currentCodeOrigin(), "\n");
    }
    return true;
}

template<typename ChecksFunctor>
bool ByteCodeParser::handleMinMax(int resultOperand, NodeType op, int registerOffset, int argumentCountIncludingThis, const ChecksFunctor& insertChecks)
{
    if (argumentCountIncludingThis == 1) { // Math.min()
        insertChecks();
        set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantNaN)));
        return true;
    }
     
    if (argumentCountIncludingThis == 2) { // Math.min(x)
        insertChecks();
        Node* result = get(VirtualRegister(virtualRegisterForArgument(1, registerOffset)));
        addToGraph(Phantom, Edge(result, NumberUse));
        set(VirtualRegister(resultOperand), result);
        return true;
    }
    
    if (argumentCountIncludingThis == 3) { // Math.min(x, y)
        insertChecks();
        set(VirtualRegister(resultOperand), addToGraph(op, get(virtualRegisterForArgument(1, registerOffset)), get(virtualRegisterForArgument(2, registerOffset))));
        return true;
    }
    
    // Don't handle >=3 arguments for now.
    return false;
}

template<typename ChecksFunctor>
bool ByteCodeParser::handleIntrinsicCall(Node* callee, int resultOperand, Intrinsic intrinsic, int registerOffset, int argumentCountIncludingThis, SpeculatedType prediction, const ChecksFunctor& insertChecks)
{
    switch (intrinsic) {

    // Intrinsic Functions:

    case AbsIntrinsic: {
        if (argumentCountIncludingThis == 1) { // Math.abs()
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantNaN)));
            return true;
        }

        if (!MacroAssembler::supportsFloatingPointAbs())
            return false;

        insertChecks();
        Node* node = addToGraph(ArithAbs, get(virtualRegisterForArgument(1, registerOffset)));
        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, Overflow))
            node->mergeFlags(NodeMayOverflowInt32InDFG);
        set(VirtualRegister(resultOperand), node);
        return true;
    }

    case MinIntrinsic:
        return handleMinMax(resultOperand, ArithMin, registerOffset, argumentCountIncludingThis, insertChecks);
        
    case MaxIntrinsic:
        return handleMinMax(resultOperand, ArithMax, registerOffset, argumentCountIncludingThis, insertChecks);

    case SqrtIntrinsic:
    case CosIntrinsic:
    case SinIntrinsic:
    case LogIntrinsic: {
        if (argumentCountIncludingThis == 1) {
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantNaN)));
            return true;
        }
        
        switch (intrinsic) {
        case SqrtIntrinsic:
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(ArithSqrt, get(virtualRegisterForArgument(1, registerOffset))));
            return true;
            
        case CosIntrinsic:
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(ArithCos, get(virtualRegisterForArgument(1, registerOffset))));
            return true;
            
        case SinIntrinsic:
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(ArithSin, get(virtualRegisterForArgument(1, registerOffset))));
            return true;

        case LogIntrinsic:
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(ArithLog, get(virtualRegisterForArgument(1, registerOffset))));
            return true;
            
        default:
            RELEASE_ASSERT_NOT_REACHED();
            return false;
        }
    }

    case PowIntrinsic: {
        if (argumentCountIncludingThis < 3) {
            // Math.pow() and Math.pow(x) return NaN.
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantNaN)));
            return true;
        }
        insertChecks();
        VirtualRegister xOperand = virtualRegisterForArgument(1, registerOffset);
        VirtualRegister yOperand = virtualRegisterForArgument(2, registerOffset);
        set(VirtualRegister(resultOperand), addToGraph(ArithPow, get(xOperand), get(yOperand)));
        return true;
    }
        
    case ArrayPushIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;
        
        ArrayMode arrayMode = getArrayMode(m_currentInstruction[OPCODE_LENGTH(op_call) - 2].u.arrayProfile);
        if (!arrayMode.isJSArray())
            return false;
        switch (arrayMode.type()) {
        case Array::Int32:
        case Array::Double:
        case Array::Contiguous:
        case Array::ArrayStorage: {
            insertChecks();
            Node* arrayPush = addToGraph(ArrayPush, OpInfo(arrayMode.asWord()), OpInfo(prediction), get(virtualRegisterForArgument(0, registerOffset)), get(virtualRegisterForArgument(1, registerOffset)));
            set(VirtualRegister(resultOperand), arrayPush);
            
            return true;
        }
            
        default:
            return false;
        }
    }
        
    case ArrayPopIntrinsic: {
        if (argumentCountIncludingThis != 1)
            return false;
        
        ArrayMode arrayMode = getArrayMode(m_currentInstruction[OPCODE_LENGTH(op_call) - 2].u.arrayProfile);
        if (!arrayMode.isJSArray())
            return false;
        switch (arrayMode.type()) {
        case Array::Int32:
        case Array::Double:
        case Array::Contiguous:
        case Array::ArrayStorage: {
            insertChecks();
            Node* arrayPop = addToGraph(ArrayPop, OpInfo(arrayMode.asWord()), OpInfo(prediction), get(virtualRegisterForArgument(0, registerOffset)));
            set(VirtualRegister(resultOperand), arrayPop);
            return true;
        }
            
        default:
            return false;
        }
    }

    case IsArrayIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;

        insertChecks();
        Node* isArray = addToGraph(IsArrayObject, OpInfo(prediction), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), isArray);
        return true;
    }

    case IsJSArrayIntrinsic: {
        ASSERT(argumentCountIncludingThis == 2);

        insertChecks();
        Node* isArray = addToGraph(IsJSArray, OpInfo(prediction), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), isArray);
        return true;
    }

    case IsArrayConstructorIntrinsic: {
        ASSERT(argumentCountIncludingThis == 2);

        insertChecks();
        Node* isArray = addToGraph(IsArrayConstructor, OpInfo(prediction), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), isArray);
        return true;
    }

    case CharCodeAtIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;

        insertChecks();
        VirtualRegister thisOperand = virtualRegisterForArgument(0, registerOffset);
        VirtualRegister indexOperand = virtualRegisterForArgument(1, registerOffset);
        Node* charCode = addToGraph(StringCharCodeAt, OpInfo(ArrayMode(Array::String).asWord()), get(thisOperand), get(indexOperand));

        set(VirtualRegister(resultOperand), charCode);
        return true;
    }

    case CharAtIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;

        insertChecks();
        VirtualRegister thisOperand = virtualRegisterForArgument(0, registerOffset);
        VirtualRegister indexOperand = virtualRegisterForArgument(1, registerOffset);
        Node* charCode = addToGraph(StringCharAt, OpInfo(ArrayMode(Array::String).asWord()), get(thisOperand), get(indexOperand));

        set(VirtualRegister(resultOperand), charCode);
        return true;
    }
    case Clz32Intrinsic: {
        insertChecks();
        if (argumentCountIncludingThis == 1)
            set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_graph.freeze(jsNumber(32)))));
        else {
            Node* operand = get(virtualRegisterForArgument(1, registerOffset));
            set(VirtualRegister(resultOperand), addToGraph(ArithClz32, operand));
        }
        return true;
    }
    case FromCharCodeIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;

        insertChecks();
        VirtualRegister indexOperand = virtualRegisterForArgument(1, registerOffset);
        Node* charCode = addToGraph(StringFromCharCode, get(indexOperand));

        set(VirtualRegister(resultOperand), charCode);

        return true;
    }

    case RegExpExecIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;
        
        insertChecks();
        Node* regExpExec = addToGraph(RegExpExec, OpInfo(0), OpInfo(prediction), addToGraph(GetGlobalObject, callee), get(virtualRegisterForArgument(0, registerOffset)), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), regExpExec);
        
        return true;
    }
        
    case RegExpTestIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;
        
        insertChecks();
        Node* regExpExec = addToGraph(RegExpTest, OpInfo(0), OpInfo(prediction), addToGraph(GetGlobalObject, callee), get(virtualRegisterForArgument(0, registerOffset)), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), regExpExec);
        
        return true;
    }

    case IsRegExpObjectIntrinsic: {
        ASSERT(argumentCountIncludingThis == 2);

        insertChecks();
        Node* isRegExpObject = addToGraph(IsRegExpObject, OpInfo(prediction), get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), isRegExpObject);
        return true;
    }

    case StringPrototypeReplaceIntrinsic: {
        if (argumentCountIncludingThis != 3)
            return false;

        insertChecks();
        Node* result = addToGraph(StringReplace, OpInfo(0), OpInfo(prediction), get(virtualRegisterForArgument(0, registerOffset)), get(virtualRegisterForArgument(1, registerOffset)), get(virtualRegisterForArgument(2, registerOffset)));
        set(VirtualRegister(resultOperand), result);
        return true;
    }
        
    case RoundIntrinsic:
    case FloorIntrinsic:
    case CeilIntrinsic:
    case TruncIntrinsic: {
        if (argumentCountIncludingThis == 1) {
            insertChecks();
            set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantNaN)));
            return true;
        }
        if (argumentCountIncludingThis == 2) {
            insertChecks();
            Node* operand = get(virtualRegisterForArgument(1, registerOffset));
            NodeType op;
            if (intrinsic == RoundIntrinsic)
                op = ArithRound;
            else if (intrinsic == FloorIntrinsic)
                op = ArithFloor;
            else if (intrinsic == CeilIntrinsic)
                op = ArithCeil;
            else {
                ASSERT(intrinsic == TruncIntrinsic);
                op = ArithTrunc;
            }
            Node* roundNode = addToGraph(op, OpInfo(0), OpInfo(prediction), operand);
            set(VirtualRegister(resultOperand), roundNode);
            return true;
        }
        return false;
    }
    case IMulIntrinsic: {
        if (argumentCountIncludingThis != 3)
            return false;
        insertChecks();
        VirtualRegister leftOperand = virtualRegisterForArgument(1, registerOffset);
        VirtualRegister rightOperand = virtualRegisterForArgument(2, registerOffset);
        Node* left = get(leftOperand);
        Node* right = get(rightOperand);
        set(VirtualRegister(resultOperand), addToGraph(ArithIMul, left, right));
        return true;
    }

    case RandomIntrinsic: {
        if (argumentCountIncludingThis != 1)
            return false;
        insertChecks();
        set(VirtualRegister(resultOperand), addToGraph(ArithRandom));
        return true;
    }
        
    case FRoundIntrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;
        insertChecks();
        VirtualRegister operand = virtualRegisterForArgument(1, registerOffset);
        set(VirtualRegister(resultOperand), addToGraph(ArithFRound, get(operand)));
        return true;
    }
        
    case DFGTrueIntrinsic: {
        insertChecks();
        set(VirtualRegister(resultOperand), jsConstant(jsBoolean(true)));
        return true;
    }
        
    case OSRExitIntrinsic: {
        insertChecks();
        addToGraph(ForceOSRExit);
        set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantUndefined)));
        return true;
    }
        
    case IsFinalTierIntrinsic: {
        insertChecks();
        set(VirtualRegister(resultOperand),
            jsConstant(jsBoolean(Options::useFTLJIT() ? isFTL(m_graph.m_plan.mode) : true)));
        return true;
    }
        
    case SetInt32HeapPredictionIntrinsic: {
        insertChecks();
        for (int i = 1; i < argumentCountIncludingThis; ++i) {
            Node* node = get(virtualRegisterForArgument(i, registerOffset));
            if (node->hasHeapPrediction())
                node->setHeapPrediction(SpecInt32);
        }
        set(VirtualRegister(resultOperand), addToGraph(JSConstant, OpInfo(m_constantUndefined)));
        return true;
    }
        
    case CheckInt32Intrinsic: {
        insertChecks();
        for (int i = 1; i < argumentCountIncludingThis; ++i) {
            Node* node = get(virtualRegisterForArgument(i, registerOffset));
            addToGraph(Phantom, Edge(node, Int32Use));
        }
        set(VirtualRegister(resultOperand), jsConstant(jsBoolean(true)));
        return true;
    }
        
    case FiatInt52Intrinsic: {
        if (argumentCountIncludingThis != 2)
            return false;
        insertChecks();
        VirtualRegister operand = virtualRegisterForArgument(1, registerOffset);
        if (enableInt52())
            set(VirtualRegister(resultOperand), addToGraph(FiatInt52, get(operand)));
        else
            set(VirtualRegister(resultOperand), get(operand));
        return true;
    }
        
    default:
        return false;
    }
}

template<typename ChecksFunctor>
bool ByteCodeParser::handleIntrinsicGetter(int resultOperand, const GetByIdVariant& variant, Node* thisNode, const ChecksFunctor& insertChecks)
{
    switch (variant.intrinsic()) {
    case TypedArrayByteLengthIntrinsic: {
        insertChecks();

        TypedArrayType type = (*variant.structureSet().begin())->classInfo()->typedArrayStorageType;
        Array::Type arrayType = toArrayType(type);
        size_t logSize = logElementSize(type);

        variant.structureSet().forEach([&] (Structure* structure) {
            TypedArrayType curType = structure->classInfo()->typedArrayStorageType;
            ASSERT(logSize == logElementSize(curType));
            arrayType = refineTypedArrayType(arrayType, curType);
            ASSERT(arrayType != Array::Generic);
        });

        Node* lengthNode = addToGraph(GetArrayLength, OpInfo(ArrayMode(arrayType).asWord()), thisNode);

        if (!logSize) {
            set(VirtualRegister(resultOperand), lengthNode);
            return true;
        }

        // We can use a BitLShift here because typed arrays will never have a byteLength
        // that overflows int32.
        Node* shiftNode = jsConstant(jsNumber(logSize));
        set(VirtualRegister(resultOperand), addToGraph(BitLShift, lengthNode, shiftNode));

        return true;
    }

    case TypedArrayLengthIntrinsic: {
        insertChecks();

        TypedArrayType type = (*variant.structureSet().begin())->classInfo()->typedArrayStorageType;
        Array::Type arrayType = toArrayType(type);

        variant.structureSet().forEach([&] (Structure* structure) {
            TypedArrayType curType = structure->classInfo()->typedArrayStorageType;
            arrayType = refineTypedArrayType(arrayType, curType);
            ASSERT(arrayType != Array::Generic);
        });

        set(VirtualRegister(resultOperand), addToGraph(GetArrayLength, OpInfo(ArrayMode(arrayType).asWord()), thisNode));

        return true;

    }

    case TypedArrayByteOffsetIntrinsic: {
        insertChecks();

        TypedArrayType type = (*variant.structureSet().begin())->classInfo()->typedArrayStorageType;
        Array::Type arrayType = toArrayType(type);

        variant.structureSet().forEach([&] (Structure* structure) {
            TypedArrayType curType = structure->classInfo()->typedArrayStorageType;
            arrayType = refineTypedArrayType(arrayType, curType);
            ASSERT(arrayType != Array::Generic);
        });

        set(VirtualRegister(resultOperand), addToGraph(GetTypedArrayByteOffset, OpInfo(ArrayMode(arrayType).asWord()), thisNode));

        return true;
    }

    default:
        return false;
    }
    RELEASE_ASSERT_NOT_REACHED();
}

template<typename ChecksFunctor>
bool ByteCodeParser::handleTypedArrayConstructor(
    int resultOperand, InternalFunction* function, int registerOffset,
    int argumentCountIncludingThis, TypedArrayType type, const ChecksFunctor& insertChecks)
{
    if (!isTypedView(type))
        return false;
    
    if (function->classInfo() != constructorClassInfoForType(type))
        return false;
    
    if (function->globalObject() != m_inlineStackTop->m_codeBlock->globalObject())
        return false;
    
    // We only have an intrinsic for the case where you say:
    //
    // new FooArray(blah);
    //
    // Of course, 'blah' could be any of the following:
    //
    // - Integer, indicating that you want to allocate an array of that length.
    //   This is the thing we're hoping for, and what we can actually do meaningful
    //   optimizations for.
    //
    // - Array buffer, indicating that you want to create a view onto that _entire_
    //   buffer.
    //
    // - Non-buffer object, indicating that you want to create a copy of that
    //   object by pretending that it quacks like an array.
    //
    // - Anything else, indicating that you want to have an exception thrown at
    //   you.
    //
    // The intrinsic, NewTypedArray, will behave as if it could do any of these
    // things up until we do Fixup. Thereafter, if child1 (i.e. 'blah') is
    // predicted Int32, then we lock it in as a normal typed array allocation.
    // Otherwise, NewTypedArray turns into a totally opaque function call that
    // may clobber the world - by virtue of it accessing properties on what could
    // be an object.
    //
    // Note that although the generic form of NewTypedArray sounds sort of awful,
    // it is actually quite likely to be more efficient than a fully generic
    // Construct. So, we might want to think about making NewTypedArray variadic,
    // or else making Construct not super slow.
    
    if (argumentCountIncludingThis != 2)
        return false;

    insertChecks();
    set(VirtualRegister(resultOperand),
        addToGraph(NewTypedArray, OpInfo(type), get(virtualRegisterForArgument(1, registerOffset))));
    return true;
}

template<typename ChecksFunctor>
bool ByteCodeParser::handleConstantInternalFunction(
    Node* callTargetNode, int resultOperand, InternalFunction* function, int registerOffset,
    int argumentCountIncludingThis, CodeSpecializationKind kind, const ChecksFunctor& insertChecks)
{
    if (verbose)
        dataLog("    Handling constant internal function ", JSValue(function), "\n");

    if (kind == CodeForConstruct) {
        Node* newTargetNode = get(virtualRegisterForArgument(0, registerOffset));
        // We cannot handle the case where new.target != callee (i.e. a construct from a super call) because we
        // don't know what the prototype of the constructed object will be.
        // FIXME: If we have inlined super calls up to the call site, however, we should be able to figure out the structure. https://bugs.webkit.org/show_bug.cgi?id=152700
        if (newTargetNode != callTargetNode)
            return false;
    }

    if (function->classInfo() == ArrayConstructor::info()) {
        if (function->globalObject() != m_inlineStackTop->m_codeBlock->globalObject())
            return false;
        
        insertChecks();
        if (argumentCountIncludingThis == 2) {
            set(VirtualRegister(resultOperand),
                addToGraph(NewArrayWithSize, OpInfo(ArrayWithUndecided), get(virtualRegisterForArgument(1, registerOffset))));
            return true;
        }
        
        for (int i = 1; i < argumentCountIncludingThis; ++i)
            addVarArgChild(get(virtualRegisterForArgument(i, registerOffset)));
        set(VirtualRegister(resultOperand),
            addToGraph(Node::VarArg, NewArray, OpInfo(ArrayWithUndecided), OpInfo(0)));
        return true;
    }
    
    if (function->classInfo() == StringConstructor::info()) {
        insertChecks();
        
        Node* result;
        
        if (argumentCountIncludingThis <= 1)
            result = jsConstant(m_vm->smallStrings.emptyString());
        else
            result = addToGraph(CallStringConstructor, get(virtualRegisterForArgument(1, registerOffset)));
        
        if (kind == CodeForConstruct)
            result = addToGraph(NewStringObject, OpInfo(function->globalObject()->stringObjectStructure()), result);
        
        set(VirtualRegister(resultOperand), result);
        return true;
    }

    // FIXME: This should handle construction as well. https://bugs.webkit.org/show_bug.cgi?id=155591
    if (function->classInfo() == ObjectConstructor::info() && kind == CodeForCall) {
        insertChecks();

        Node* result = addToGraph(CallObjectConstructor, get(virtualRegisterForArgument(1, registerOffset)));
        set(VirtualRegister(resultOperand), result);
        return true;
    }

    for (unsigned typeIndex = 0; typeIndex < NUMBER_OF_TYPED_ARRAY_TYPES; ++typeIndex) {
        bool result = handleTypedArrayConstructor(
            resultOperand, function, registerOffset, argumentCountIncludingThis,
            indexToTypedArrayType(typeIndex), insertChecks);
        if (result)
            return true;
    }
    
    return false;
}

Node* ByteCodeParser::handleGetByOffset(
    SpeculatedType prediction, Node* base, unsigned identifierNumber, PropertyOffset offset,
    const InferredType::Descriptor& inferredType, NodeType op)
{
    Node* propertyStorage;
    if (isInlineOffset(offset))
        propertyStorage = base;
    else
        propertyStorage = addToGraph(GetButterfly, base);
    
    StorageAccessData* data = m_graph.m_storageAccessData.add();
    data->offset = offset;
    data->identifierNumber = identifierNumber;
    data->inferredType = inferredType;
    m_graph.registerInferredType(inferredType);
    
    Node* getByOffset = addToGraph(op, OpInfo(data), OpInfo(prediction), propertyStorage, base);

    return getByOffset;
}

Node* ByteCodeParser::handlePutByOffset(
    Node* base, unsigned identifier, PropertyOffset offset, const InferredType::Descriptor& inferredType,
    Node* value)
{
    Node* propertyStorage;
    if (isInlineOffset(offset))
        propertyStorage = base;
    else
        propertyStorage = addToGraph(GetButterfly, base);
    
    StorageAccessData* data = m_graph.m_storageAccessData.add();
    data->offset = offset;
    data->identifierNumber = identifier;
    data->inferredType = inferredType;
    m_graph.registerInferredType(inferredType);
    
    Node* result = addToGraph(PutByOffset, OpInfo(data), propertyStorage, base, value);
    
    return result;
}

bool ByteCodeParser::check(const ObjectPropertyCondition& condition)
{
    if (!condition)
        return false;
    
    if (m_graph.watchCondition(condition))
        return true;
    
    Structure* structure = condition.object()->structure();
    if (!condition.structureEnsuresValidity(structure))
        return false;
    
    addToGraph(
        CheckStructure,
        OpInfo(m_graph.addStructureSet(structure)),
        weakJSConstant(condition.object()));
    return true;
}

GetByOffsetMethod ByteCodeParser::promoteToConstant(GetByOffsetMethod method)
{
    if (method.kind() == GetByOffsetMethod::LoadFromPrototype
        && method.prototype()->structure()->dfgShouldWatch()) {
        if (JSValue constant = m_graph.tryGetConstantProperty(method.prototype()->value(), method.prototype()->structure(), method.offset()))
            return GetByOffsetMethod::constant(m_graph.freeze(constant));
    }
    
    return method;
}

bool ByteCodeParser::needsDynamicLookup(ResolveType type, OpcodeID opcode)
{
    ASSERT(opcode == op_resolve_scope || opcode == op_get_from_scope || opcode == op_put_to_scope);

    JSGlobalObject* globalObject = m_inlineStackTop->m_codeBlock->globalObject();
    if (needsVarInjectionChecks(type) && globalObject->varInjectionWatchpoint()->hasBeenInvalidated())
        return true;

    switch (type) {
    case GlobalProperty:
    case GlobalVar:
    case GlobalLexicalVar:
    case ClosureVar:
    case LocalClosureVar:
    case ModuleVar:
        return false;

    case UnresolvedProperty:
    case UnresolvedPropertyWithVarInjectionChecks: {
        // The heuristic for UnresolvedProperty scope accesses is we will ForceOSRExit if we
        // haven't exited from from this access before to let the baseline JIT try to better
        // cache the access. If we've already exited from this operation, it's unlikely that
        // the baseline will come up with a better ResolveType and instead we will compile
        // this as a dynamic scope access.

        // We only track our heuristic through resolve_scope since resolve_scope will
        // dominate unresolved gets/puts on that scope.
        if (opcode != op_resolve_scope)
            return true;

        if (m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, InadequateCoverage)) {
            // We've already exited so give up on getting better ResolveType information.
            return true;
        }

        // We have not exited yet, so let's have the baseline get better ResolveType information for us.
        // This type of code is often seen when we tier up in a loop but haven't executed the part
        // of a function that comes after the loop.
        return false;
    }

    case Dynamic:
        return true;

    case GlobalPropertyWithVarInjectionChecks:
    case GlobalVarWithVarInjectionChecks:
    case GlobalLexicalVarWithVarInjectionChecks:
    case ClosureVarWithVarInjectionChecks:
        return false;
    }

    ASSERT_NOT_REACHED();
    return false;
}

GetByOffsetMethod ByteCodeParser::planLoad(const ObjectPropertyCondition& condition)
{
    if (verbose)
        dataLog("Planning a load: ", condition, "\n");
    
    // We might promote this to Equivalence, and a later DFG pass might also do such promotion
    // even if we fail, but for simplicity this cannot be asked to load an equivalence condition.
    // None of the clients of this method will request a load of an Equivalence condition anyway,
    // and supporting it would complicate the heuristics below.
    RELEASE_ASSERT(condition.kind() == PropertyCondition::Presence);
    
    // Here's the ranking of how to handle this, from most preferred to least preferred:
    //
    // 1) Watchpoint on an equivalence condition and return a constant node for the loaded value.
    //    No other code is emitted, and the structure of the base object is never registered.
    //    Hence this results in zero code and we won't jettison this compilation if the object
    //    transitions, even if the structure is watchable right now.
    //
    // 2) Need to emit a load, and the current structure of the base is going to be watched by the
    //    DFG anyway (i.e. dfgShouldWatch). Watch the structure and emit the load. Don't watch the
    //    condition, since the act of turning the base into a constant in IR will cause the DFG to
    //    watch the structure anyway and doing so would subsume watching the condition.
    //
    // 3) Need to emit a load, and the current structure of the base is watchable but not by the
    //    DFG (i.e. transitionWatchpointSetIsStillValid() and !dfgShouldWatchIfPossible()). Watch
    //    the condition, and emit a load.
    //
    // 4) Need to emit a load, and the current structure of the base is not watchable. Emit a
    //    structure check, and emit a load.
    //
    // 5) The condition does not hold. Give up and return null.
    
    // First, try to promote Presence to Equivalence. We do this before doing anything else
    // because it's the most profitable. Also, there are cases where the presence is watchable but
    // we don't want to watch it unless it became an equivalence (see the relationship between
    // (1), (2), and (3) above).
    ObjectPropertyCondition equivalenceCondition = condition.attemptToMakeEquivalenceWithoutBarrier();
    if (m_graph.watchCondition(equivalenceCondition))
        return GetByOffsetMethod::constant(m_graph.freeze(equivalenceCondition.requiredValue()));
    
    // At this point, we'll have to materialize the condition's base as a constant in DFG IR. Once
    // we do this, the frozen value will have its own idea of what the structure is. Use that from
    // now on just because it's less confusing.
    FrozenValue* base = m_graph.freeze(condition.object());
    Structure* structure = base->structure();
    
    // Check if the structure that we've registered makes the condition hold. If not, just give
    // up. This is case (5) above.
    if (!condition.structureEnsuresValidity(structure))
        return GetByOffsetMethod();
    
    // If the structure is watched by the DFG already, then just use this fact to emit the load.
    // This is case (2) above.
    if (structure->dfgShouldWatch())
        return promoteToConstant(GetByOffsetMethod::loadFromPrototype(base, condition.offset()));
    
    // If we can watch the condition right now, then we can emit the load after watching it. This
    // is case (3) above.
    if (m_graph.watchCondition(condition))
        return promoteToConstant(GetByOffsetMethod::loadFromPrototype(base, condition.offset()));
    
    // We can't watch anything but we know that the current structure satisfies the condition. So,
    // check for that structure and then emit the load.
    addToGraph(
        CheckStructure, 
        OpInfo(m_graph.addStructureSet(structure)),
        addToGraph(JSConstant, OpInfo(base)));
    return promoteToConstant(GetByOffsetMethod::loadFromPrototype(base, condition.offset()));
}

Node* ByteCodeParser::load(
    SpeculatedType prediction, unsigned identifierNumber, const GetByOffsetMethod& method,
    NodeType op)
{
    switch (method.kind()) {
    case GetByOffsetMethod::Invalid:
        return nullptr;
    case GetByOffsetMethod::Constant:
        return addToGraph(JSConstant, OpInfo(method.constant()));
    case GetByOffsetMethod::LoadFromPrototype: {
        Node* baseNode = addToGraph(JSConstant, OpInfo(method.prototype()));
        return handleGetByOffset(
            prediction, baseNode, identifierNumber, method.offset(), InferredType::Top, op);
    }
    case GetByOffsetMethod::Load:
        // Will never see this from planLoad().
        RELEASE_ASSERT_NOT_REACHED();
        return nullptr;
    }
    
    RELEASE_ASSERT_NOT_REACHED();
    return nullptr;
}

Node* ByteCodeParser::load(
    SpeculatedType prediction, const ObjectPropertyCondition& condition, NodeType op)
{
    GetByOffsetMethod method = planLoad(condition);
    return load(prediction, m_graph.identifiers().ensure(condition.uid()), method, op);
}

bool ByteCodeParser::check(const ObjectPropertyConditionSet& conditionSet)
{
    for (const ObjectPropertyCondition condition : conditionSet) {
        if (!check(condition))
            return false;
    }
    return true;
}

GetByOffsetMethod ByteCodeParser::planLoad(const ObjectPropertyConditionSet& conditionSet)
{
    if (verbose)
        dataLog("conditionSet = ", conditionSet, "\n");
    
    GetByOffsetMethod result;
    for (const ObjectPropertyCondition condition : conditionSet) {
        switch (condition.kind()) {
        case PropertyCondition::Presence:
            RELEASE_ASSERT(!result); // Should only see exactly one of these.
            result = planLoad(condition);
            if (!result)
                return GetByOffsetMethod();
            break;
        default:
            if (!check(condition))
                return GetByOffsetMethod();
            break;
        }
    }
    RELEASE_ASSERT(!!result);
    return result;
}

Node* ByteCodeParser::load(
    SpeculatedType prediction, const ObjectPropertyConditionSet& conditionSet, NodeType op)
{
    GetByOffsetMethod method = planLoad(conditionSet);
    return load(
        prediction,
        m_graph.identifiers().ensure(conditionSet.slotBaseCondition().uid()),
        method, op);
}

ObjectPropertyCondition ByteCodeParser::presenceLike(
    JSObject* knownBase, UniquedStringImpl* uid, PropertyOffset offset, const StructureSet& set)
{
    if (set.isEmpty())
        return ObjectPropertyCondition();
    unsigned attributes;
    PropertyOffset firstOffset = set[0]->getConcurrently(uid, attributes);
    if (firstOffset != offset)
        return ObjectPropertyCondition();
    for (unsigned i = 1; i < set.size(); ++i) {
        unsigned otherAttributes;
        PropertyOffset otherOffset = set[i]->getConcurrently(uid, otherAttributes);
        if (otherOffset != offset || otherAttributes != attributes)
            return ObjectPropertyCondition();
    }
    return ObjectPropertyCondition::presenceWithoutBarrier(knownBase, uid, offset, attributes);
}

bool ByteCodeParser::checkPresenceLike(
    JSObject* knownBase, UniquedStringImpl* uid, PropertyOffset offset, const StructureSet& set)
{
    return check(presenceLike(knownBase, uid, offset, set));
}

void ByteCodeParser::checkPresenceLike(
    Node* base, UniquedStringImpl* uid, PropertyOffset offset, const StructureSet& set)
{
    if (JSObject* knownBase = base->dynamicCastConstant<JSObject*>()) {
        if (checkPresenceLike(knownBase, uid, offset, set))
            return;
    }

    addToGraph(CheckStructure, OpInfo(m_graph.addStructureSet(set)), base);
}

template<typename VariantType>
Node* ByteCodeParser::load(
    SpeculatedType prediction, Node* base, unsigned identifierNumber, const VariantType& variant)
{
    // Make sure backwards propagation knows that we've used base.
    addToGraph(Phantom, base);
    
    bool needStructureCheck = true;
    
    UniquedStringImpl* uid = m_graph.identifiers()[identifierNumber];
    
    if (JSObject* knownBase = base->dynamicCastConstant<JSObject*>()) {
        // Try to optimize away the structure check. Note that it's not worth doing anything about this
        // if the base's structure is watched.
        Structure* structure = base->constant()->structure();
        if (!structure->dfgShouldWatch()) {
            if (!variant.conditionSet().isEmpty()) {
                // This means that we're loading from a prototype. We expect the base not to have the
                // property. We can only use ObjectPropertyCondition if all of the structures in the
                // variant.structureSet() agree on the prototype (it would be hilariously rare if they
                // didn't). Note that we are relying on structureSet() having at least one element. That
                // will always be true here because of how GetByIdStatus/PutByIdStatus work.
                JSObject* prototype = variant.structureSet()[0]->storedPrototypeObject();
                bool allAgree = true;
                for (unsigned i = 1; i < variant.structureSet().size(); ++i) {
                    if (variant.structureSet()[i]->storedPrototypeObject() != prototype) {
                        allAgree = false;
                        break;
                    }
                }
                if (allAgree) {
                    ObjectPropertyCondition condition = ObjectPropertyCondition::absenceWithoutBarrier(
                        knownBase, uid, prototype);
                    if (check(condition))
                        needStructureCheck = false;
                }
            } else {
                // This means we're loading directly from base. We can avoid all of the code that follows
                // if we can prove that the property is a constant. Otherwise, we try to prove that the
                // property is watchably present, in which case we get rid of the structure check.

                ObjectPropertyCondition presenceCondition =
                    presenceLike(knownBase, uid, variant.offset(), variant.structureSet());
                if (presenceCondition) {
                    ObjectPropertyCondition equivalenceCondition =
                        presenceCondition.attemptToMakeEquivalenceWithoutBarrier();
                    if (m_graph.watchCondition(equivalenceCondition))
                        return weakJSConstant(equivalenceCondition.requiredValue());
                    
                    if (check(presenceCondition))
                        needStructureCheck = false;
                }
            }
        }
    }

    if (needStructureCheck)
        addToGraph(CheckStructure, OpInfo(m_graph.addStructureSet(variant.structureSet())), base);
    
    SpeculatedType loadPrediction;
    NodeType loadOp;
    if (variant.callLinkStatus() || variant.intrinsic() != NoIntrinsic) {
        loadPrediction = SpecCellOther;
        loadOp = GetGetterSetterByOffset;
    } else {
        loadPrediction = prediction;
        loadOp = GetByOffset;
    }
    
    Node* loadedValue;
    if (!variant.conditionSet().isEmpty())
        loadedValue = load(loadPrediction, variant.conditionSet(), loadOp);
    else {
        if (needStructureCheck && base->hasConstant()) {
            // We did emit a structure check. That means that we have an opportunity to do constant folding
            // here, since we didn't do it above.
            JSValue constant = m_graph.tryGetConstantProperty(
                base->asJSValue(), variant.structureSet(), variant.offset());
            if (constant)
                return weakJSConstant(constant);
        }

        InferredType::Descriptor inferredType;
        if (needStructureCheck) {
            for (Structure* structure : variant.structureSet()) {
                InferredType::Descriptor thisType = m_graph.inferredTypeForProperty(structure, uid);
                inferredType.merge(thisType);
            }
        } else
            inferredType = InferredType::Top;
        
        loadedValue = handleGetByOffset(
            loadPrediction, base, identifierNumber, variant.offset(), inferredType, loadOp);
    }

    return loadedValue;
}

Node* ByteCodeParser::store(Node* base, unsigned identifier, const PutByIdVariant& variant, Node* value)
{
    RELEASE_ASSERT(variant.kind() == PutByIdVariant::Replace);

    checkPresenceLike(base, m_graph.identifiers()[identifier], variant.offset(), variant.structure());
    return handlePutByOffset(base, identifier, variant.offset(), variant.requiredType(), value);
}

void ByteCodeParser::handleGetById(
    int destinationOperand, SpeculatedType prediction, Node* base, unsigned identifierNumber,
    GetByIdStatus getByIdStatus, AccessType type)
{
    // Attempt to reduce the set of things in the GetByIdStatus.
    if (base->op() == NewObject) {
        bool ok = true;
        for (unsigned i = m_currentBlock->size(); i--;) {
            Node* node = m_currentBlock->at(i);
            if (node == base)
                break;
            if (writesOverlap(m_graph, node, JSCell_structureID)) {
                ok = false;
                break;
            }
        }
        if (ok)
            getByIdStatus.filter(base->structure());
    }
    
    NodeType getById;
    if (type == AccessType::Get)
        getById = getByIdStatus.makesCalls() ? GetByIdFlush : GetById;
    else
        getById = TryGetById;

    ASSERT(type == AccessType::Get || !getByIdStatus.makesCalls());
    if (!getByIdStatus.isSimple() || !getByIdStatus.numVariants() || !Options::useAccessInlining()) {
        set(VirtualRegister(destinationOperand),
            addToGraph(getById, OpInfo(identifierNumber), OpInfo(prediction), base));
        return;
    }
    
    if (getByIdStatus.numVariants() > 1) {
        if (getByIdStatus.makesCalls() || !isFTL(m_graph.m_plan.mode)
            || !Options::usePolymorphicAccessInlining()) {
            set(VirtualRegister(destinationOperand),
                addToGraph(getById, OpInfo(identifierNumber), OpInfo(prediction), base));
            return;
        }
        
        Vector<MultiGetByOffsetCase, 2> cases;
        
        // 1) Emit prototype structure checks for all chains. This could sort of maybe not be
        //    optimal, if there is some rarely executed case in the chain that requires a lot
        //    of checks and those checks are not watchpointable.
        for (const GetByIdVariant& variant : getByIdStatus.variants()) {
            if (variant.intrinsic() != NoIntrinsic) {
                set(VirtualRegister(destinationOperand),
                    addToGraph(getById, OpInfo(identifierNumber), OpInfo(prediction), base));
                return;
            }

            if (variant.conditionSet().isEmpty()) {
                cases.append(
                    MultiGetByOffsetCase(
                        variant.structureSet(),
                        GetByOffsetMethod::load(variant.offset())));
                continue;
            }
            
            GetByOffsetMethod method = planLoad(variant.conditionSet());
            if (!method) {
                set(VirtualRegister(destinationOperand),
                    addToGraph(getById, OpInfo(identifierNumber), OpInfo(prediction), base));
                return;
            }
            
            cases.append(MultiGetByOffsetCase(variant.structureSet(), method));
        }

        if (m_graph.compilation())
            m_graph.compilation()->noticeInlinedGetById();
    
        // 2) Emit a MultiGetByOffset
        MultiGetByOffsetData* data = m_graph.m_multiGetByOffsetData.add();
        data->cases = cases;
        data->identifierNumber = identifierNumber;
        set(VirtualRegister(destinationOperand),
            addToGraph(MultiGetByOffset, OpInfo(data), OpInfo(prediction), base));
        return;
    }
    
    ASSERT(getByIdStatus.numVariants() == 1);
    GetByIdVariant variant = getByIdStatus[0];
                
    Node* loadedValue = load(prediction, base, identifierNumber, variant);
    if (!loadedValue) {
        set(VirtualRegister(destinationOperand),
            addToGraph(getById, OpInfo(identifierNumber), OpInfo(prediction), base));
        return;
    }

    if (m_graph.compilation())
        m_graph.compilation()->noticeInlinedGetById();

    ASSERT(type == AccessType::Get || !variant.callLinkStatus());
    if (!variant.callLinkStatus() && variant.intrinsic() == NoIntrinsic) {
        set(VirtualRegister(destinationOperand), loadedValue);
        return;
    }
    
    Node* getter = addToGraph(GetGetter, loadedValue);

    if (handleIntrinsicGetter(destinationOperand, variant, base,
            [&] () {
                addToGraph(CheckCell, OpInfo(m_graph.freeze(variant.intrinsicFunction())), getter, base);
            })) {
        addToGraph(Phantom, getter);
        return;
    }

    ASSERT(variant.intrinsic() == NoIntrinsic);

    // Make a call. We don't try to get fancy with using the smallest operand number because
    // the stack layout phase should compress the stack anyway.
    
    unsigned numberOfParameters = 0;
    numberOfParameters++; // The 'this' argument.
    numberOfParameters++; // True return PC.
    
    // Start with a register offset that corresponds to the last in-use register.
    int registerOffset = virtualRegisterForLocal(
        m_inlineStackTop->m_profiledBlock->m_numCalleeLocals - 1).offset();
    registerOffset -= numberOfParameters;
    registerOffset -= JSStack::CallFrameHeaderSize;
    
    // Get the alignment right.
    registerOffset = -WTF::roundUpToMultipleOf(
        stackAlignmentRegisters(),
        -registerOffset);
    
    ensureLocals(
        m_inlineStackTop->remapOperand(
            VirtualRegister(registerOffset)).toLocal());
    
    // Issue SetLocals. This has two effects:
    // 1) That's how handleCall() sees the arguments.
    // 2) If we inline then this ensures that the arguments are flushed so that if you use
    //    the dreaded arguments object on the getter, the right things happen. Well, sort of -
    //    since we only really care about 'this' in this case. But we're not going to take that
    //    shortcut.
    int nextRegister = registerOffset + JSStack::CallFrameHeaderSize;
    set(VirtualRegister(nextRegister++), base, ImmediateNakedSet);

    // We've set some locals, but they are not user-visible. It's still OK to exit from here.
    m_exitOK = true;
    addToGraph(ExitOK);
    
    handleCall(
        destinationOperand, Call, InlineCallFrame::GetterCall, OPCODE_LENGTH(op_get_by_id),
        getter, numberOfParameters - 1, registerOffset, *variant.callLinkStatus(), prediction);
}

void ByteCodeParser::emitPutById(
    Node* base, unsigned identifierNumber, Node* value, const PutByIdStatus& putByIdStatus, bool isDirect)
{
    if (isDirect)
        addToGraph(PutByIdDirect, OpInfo(identifierNumber), base, value);
    else
        addToGraph(putByIdStatus.makesCalls() ? PutByIdFlush : PutById, OpInfo(identifierNumber), base, value);
}

void ByteCodeParser::handlePutById(
    Node* base, unsigned identifierNumber, Node* value,
    const PutByIdStatus& putByIdStatus, bool isDirect)
{
    if (!putByIdStatus.isSimple() || !putByIdStatus.numVariants() || !Options::useAccessInlining()) {
        if (!putByIdStatus.isSet())
            addToGraph(ForceOSRExit);
        emitPutById(base, identifierNumber, value, putByIdStatus, isDirect);
        return;
    }
    
    if (putByIdStatus.numVariants() > 1) {
        if (!isFTL(m_graph.m_plan.mode) || putByIdStatus.makesCalls()
            || !Options::usePolymorphicAccessInlining()) {
            emitPutById(base, identifierNumber, value, putByIdStatus, isDirect);
            return;
        }
        
        if (!isDirect) {
            for (unsigned variantIndex = putByIdStatus.numVariants(); variantIndex--;) {
                if (putByIdStatus[variantIndex].kind() != PutByIdVariant::Transition)