C++ BitVector::get方法代码示例

 bool run()
 {
     ASSERT(m_graph.m_form != SSA);
     
     BitVector blocksThatNeedInvalidationPoints;
     
     for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
         BasicBlock* block = m_graph.block(blockIndex);
         if (!block)
             continue;
         
         for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex)
             handle(nodeIndex, block->at(nodeIndex));
         
         // Note: this assumes that control flow occurs at bytecode instruction boundaries.
         if (m_originThatHadFire.isSet()) {
             for (unsigned i = block->numSuccessors(); i--;)
                 blocksThatNeedInvalidationPoints.set(block->successor(i)->index);
         }
         
         m_insertionSet.execute(block);
     }
     
     for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
         if (!blocksThatNeedInvalidationPoints.get(blockIndex))
             continue;
         
         BasicBlock* block = m_graph.block(blockIndex);
         insertInvalidationCheck(0, block->at(0));
         m_insertionSet.execute(block);
     }
     
     return true;
 }

bool BitVector::equalsSlowCase(const BitVector& other) const
{
    // This is really cheesy, but probably good enough for now.
    for (unsigned i = std::max(size(), other.size()); i--;) {
        if (get(i) != other.get(i))
            return false;
    }
    return true;
}

void JITCompiler::link(LinkBuffer& linkBuffer)
{
    // Link the code, populate data in CodeBlock data structures.
    m_jitCode->common.frameRegisterCount = m_graph.frameRegisterCount();
    m_jitCode->common.requiredRegisterCountForExit = m_graph.requiredRegisterCountForExit();

    if (!m_graph.m_plan.inlineCallFrames->isEmpty())
        m_jitCode->common.inlineCallFrames = m_graph.m_plan.inlineCallFrames;
    
#if USE(JSVALUE32_64)
    m_jitCode->common.doubleConstants = WTFMove(m_graph.m_doubleConstants);
#endif
    
    m_graph.registerFrozenValues();

    BitVector usedJumpTables;
    for (Bag<SwitchData>::iterator iter = m_graph.m_switchData.begin(); !!iter; ++iter) {
        SwitchData& data = **iter;
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind == SwitchString)
            continue;
        
        RELEASE_ASSERT(data.kind == SwitchImm || data.kind == SwitchChar);
        
        usedJumpTables.set(data.switchTableIndex);
        SimpleJumpTable& table = m_codeBlock->switchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough.block->index]);
        table.ctiOffsets.grow(table.branchOffsets.size());
        for (unsigned j = table.ctiOffsets.size(); j--;)
            table.ctiOffsets[j] = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            table.ctiOffsets[myCase.value.switchLookupValue(data.kind) - table.min] =
                linkBuffer.locationOf(m_blockHeads[myCase.target.block->index]);
        }
    }
    
    for (unsigned i = m_codeBlock->numberOfSwitchJumpTables(); i--;) {
        if (usedJumpTables.get(i))
            continue;
        
        m_codeBlock->switchJumpTable(i).clear();
    }

    // NOTE: we cannot clear string switch tables because (1) we're running concurrently
    // and we cannot deref StringImpl's and (2) it would be weird to deref those
    // StringImpl's since we refer to them.
    for (Bag<SwitchData>::iterator switchDataIter = m_graph.m_switchData.begin(); !!switchDataIter; ++switchDataIter) {
        SwitchData& data = **switchDataIter;
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind != SwitchString)
            continue;
        
        StringJumpTable& table = m_codeBlock->stringSwitchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough.block->index]);
        StringJumpTable::StringOffsetTable::iterator iter;
        StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
        for (iter = table.offsetTable.begin(); iter != end; ++iter)
            iter->value.ctiOffset = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            iter = table.offsetTable.find(myCase.value.stringImpl());
            RELEASE_ASSERT(iter != end);
            iter->value.ctiOffset = linkBuffer.locationOf(m_blockHeads[myCase.target.block->index]);
        }
    }

    // Link all calls out from the JIT code to their respective functions.
    for (unsigned i = 0; i < m_calls.size(); ++i)
        linkBuffer.link(m_calls[i].m_call, m_calls[i].m_function);

    for (unsigned i = m_getByIds.size(); i--;)
        m_getByIds[i].finalize(linkBuffer);
    for (unsigned i = m_putByIds.size(); i--;)
        m_putByIds[i].finalize(linkBuffer);

    for (unsigned i = 0; i < m_ins.size(); ++i) {
        StructureStubInfo& info = *m_ins[i].m_stubInfo;
        CodeLocationCall callReturnLocation = linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->call());
        info.patch.deltaCallToDone = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_done));
        info.patch.deltaCallToJump = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_jump));
        info.callReturnLocation = callReturnLocation;
        info.patch.deltaCallToSlowCase = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->label()));
    }
    
    for (unsigned i = 0; i < m_jsCalls.size(); ++i) {
        JSCallRecord& record = m_jsCalls[i];
        CallLinkInfo& info = *record.m_info;
        linkBuffer.link(record.m_slowCall, FunctionPtr(m_vm->getCTIStub(linkCallThunkGenerator).code().executableAddress()));
        info.setCallLocations(linkBuffer.locationOfNearCall(record.m_slowCall),
            linkBuffer.locationOf(record.m_targetToCheck),
            linkBuffer.locationOfNearCall(record.m_fastCall));
    }
    
    MacroAssemblerCodeRef osrExitThunk = vm()->getCTIStub(osrExitGenerationThunkGenerator);
    CodeLocationLabel target = CodeLocationLabel(osrExitThunk.code());
//.........这里部分代码省略.........

String StylePropertySet::asText() const
{
    StringBuilder result;

    const CSSProperty* positionXProp = 0;
    const CSSProperty* positionYProp = 0;
    const CSSProperty* repeatXProp = 0;
    const CSSProperty* repeatYProp = 0;

    // FIXME: Stack-allocate the buffer for these BitVectors.
    BitVector shorthandPropertyUsed;
    BitVector shorthandPropertyAppeared;

    unsigned size = m_properties.size();
    for (unsigned n = 0; n < size; ++n) {
        const CSSProperty& prop = m_properties[n];
        CSSPropertyID propertyID = prop.id();
        CSSPropertyID shorthandPropertyID = CSSPropertyInvalid;
        CSSPropertyID borderFallbackShorthandProperty = CSSPropertyInvalid;
        String value;

        switch (propertyID) {
        case CSSPropertyBackgroundPositionX:
            positionXProp = &prop;
            continue;
        case CSSPropertyBackgroundPositionY:
            positionYProp = &prop;
            continue;
        case CSSPropertyBackgroundRepeatX:
            repeatXProp = &prop;
            continue;
        case CSSPropertyBackgroundRepeatY:
            repeatYProp = &prop;
            continue;
        case CSSPropertyBorderTopWidth:
        case CSSPropertyBorderRightWidth:
        case CSSPropertyBorderBottomWidth:
        case CSSPropertyBorderLeftWidth:
            if (!borderFallbackShorthandProperty)
                borderFallbackShorthandProperty = CSSPropertyBorderWidth;
        case CSSPropertyBorderTopStyle:
        case CSSPropertyBorderRightStyle:
        case CSSPropertyBorderBottomStyle:
        case CSSPropertyBorderLeftStyle:
            if (!borderFallbackShorthandProperty)
                borderFallbackShorthandProperty = CSSPropertyBorderStyle;
        case CSSPropertyBorderTopColor:
        case CSSPropertyBorderRightColor:
        case CSSPropertyBorderBottomColor:
        case CSSPropertyBorderLeftColor:
            if (!borderFallbackShorthandProperty)
                borderFallbackShorthandProperty = CSSPropertyBorderColor;

            // FIXME: Deal with cases where only some of border-(top|right|bottom|left) are specified.
            if (!shorthandPropertyAppeared.get(CSSPropertyBorder - firstCSSProperty)) {
                value = borderPropertyValue(ReturnNullOnUncommonValues);
                if (value.isNull())
                    shorthandPropertyAppeared.ensureSizeAndSet(CSSPropertyBorder - firstCSSProperty, numCSSProperties);
                else
                    shorthandPropertyID = CSSPropertyBorder;
            } else if (shorthandPropertyUsed.get(CSSPropertyBorder - firstCSSProperty))
                shorthandPropertyID = CSSPropertyBorder;
            if (!shorthandPropertyID)
                shorthandPropertyID = borderFallbackShorthandProperty;
            break;
        case CSSPropertyWebkitBorderHorizontalSpacing:
        case CSSPropertyWebkitBorderVerticalSpacing:
            shorthandPropertyID = CSSPropertyBorderSpacing;
            break;
        case CSSPropertyFontFamily:
        case CSSPropertyLineHeight:
        case CSSPropertyFontSize:
        case CSSPropertyFontStyle:
        case CSSPropertyFontVariant:
        case CSSPropertyFontWeight:
            // Don't use CSSPropertyFont because old UAs can't recognize them but are important for editing.
            break;
        case CSSPropertyListStyleType:
        case CSSPropertyListStylePosition:
        case CSSPropertyListStyleImage:
            shorthandPropertyID = CSSPropertyListStyle;
            break;
        case CSSPropertyMarginTop:
        case CSSPropertyMarginRight:
        case CSSPropertyMarginBottom:
        case CSSPropertyMarginLeft:
            shorthandPropertyID = CSSPropertyMargin;
            break;
        case CSSPropertyOutlineWidth:
        case CSSPropertyOutlineStyle:
        case CSSPropertyOutlineColor:
            shorthandPropertyID = CSSPropertyOutline;
            break;
        case CSSPropertyOverflowX:
        case CSSPropertyOverflowY:
            shorthandPropertyID = CSSPropertyOverflow;
            break;
        case CSSPropertyPaddingTop:
        case CSSPropertyPaddingRight:
        case CSSPropertyPaddingBottom:
//.........这里部分代码省略.........

void JITCompiler::link(LinkBuffer& linkBuffer)
{
    // Link the code, populate data in CodeBlock data structures.
#if DFG_ENABLE(DEBUG_VERBOSE)
    dataLogF("JIT code for %p start at [%p, %p). Size = %zu.\n", m_codeBlock, linkBuffer.debugAddress(), static_cast<char*>(linkBuffer.debugAddress()) + linkBuffer.debugSize(), linkBuffer.debugSize());
#endif
    
    if (!m_graph.m_inlineCallFrames->isEmpty()) {
        m_graph.m_inlineCallFrames->shrinkToFit();
        m_jitCode->common.inlineCallFrames = m_graph.m_inlineCallFrames.release();
    }

    BitVector usedJumpTables;
    for (unsigned i = m_graph.m_switchData.size(); i--;) {
        SwitchData& data = m_graph.m_switchData[i];
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind == SwitchString)
            continue;
        
        RELEASE_ASSERT(data.kind == SwitchImm || data.kind == SwitchChar);
        
        usedJumpTables.set(data.switchTableIndex);
        SimpleJumpTable& table = m_codeBlock->switchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
        table.ctiOffsets.grow(table.branchOffsets.size());
        for (unsigned j = table.ctiOffsets.size(); j--;)
            table.ctiOffsets[j] = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            table.ctiOffsets[myCase.value.switchLookupValue() - table.min] =
                linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
        }
    }
    
    for (unsigned i = m_codeBlock->numberOfSwitchJumpTables(); i--;) {
        if (usedJumpTables.get(i))
            continue;
        
        m_codeBlock->switchJumpTable(i).clear();
    }

    // NOTE: we cannot clear string switch tables because (1) we're running concurrently
    // and we cannot deref StringImpl's and (2) it would be weird to deref those
    // StringImpl's since we refer to them.
    for (unsigned i = m_graph.m_switchData.size(); i--;) {
        SwitchData& data = m_graph.m_switchData[i];
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind != SwitchString)
            continue;
        
        StringJumpTable& table = m_codeBlock->stringSwitchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
        StringJumpTable::StringOffsetTable::iterator iter;
        StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
        for (iter = table.offsetTable.begin(); iter != end; ++iter)
            iter->value.ctiOffset = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            iter = table.offsetTable.find(myCase.value.stringImpl());
            RELEASE_ASSERT(iter != end);
            iter->value.ctiOffset = linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
        }
    }

    // Link all calls out from the JIT code to their respective functions.
    for (unsigned i = 0; i < m_calls.size(); ++i)
        linkBuffer.link(m_calls[i].m_call, m_calls[i].m_function);

    m_codeBlock->setNumberOfStructureStubInfos(m_propertyAccesses.size() + m_ins.size());
    for (unsigned i = 0; i < m_propertyAccesses.size(); ++i) {
        StructureStubInfo& info = m_codeBlock->structureStubInfo(i);
        CodeLocationCall callReturnLocation = linkBuffer.locationOf(m_propertyAccesses[i].m_slowPathGenerator->call());
        info.codeOrigin = m_propertyAccesses[i].m_codeOrigin;
        info.callReturnLocation = callReturnLocation;
        info.patch.dfg.deltaCheckImmToCall = differenceBetweenCodePtr(linkBuffer.locationOf(m_propertyAccesses[i].m_structureImm), callReturnLocation);
        info.patch.dfg.deltaCallToStructCheck = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_structureCheck));
#if USE(JSVALUE64)
        info.patch.dfg.deltaCallToLoadOrStore = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_loadOrStore));
#else
        info.patch.dfg.deltaCallToTagLoadOrStore = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_tagLoadOrStore));
        info.patch.dfg.deltaCallToPayloadLoadOrStore = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_payloadLoadOrStore));
#endif
        info.patch.dfg.deltaCallToSlowCase = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_slowPathGenerator->label()));
        info.patch.dfg.deltaCallToDone = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_done));
        info.patch.dfg.deltaCallToStorageLoad = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_propertyAccesses[i].m_propertyStorageLoad));
        info.patch.dfg.baseGPR = m_propertyAccesses[i].m_baseGPR;
#if USE(JSVALUE64)
        info.patch.dfg.valueGPR = m_propertyAccesses[i].m_valueGPR;
#else
        info.patch.dfg.valueTagGPR = m_propertyAccesses[i].m_valueTagGPR;
        info.patch.dfg.valueGPR = m_propertyAccesses[i].m_valueGPR;
#endif
        m_propertyAccesses[i].m_usedRegisters.copyInfo(info.patch.dfg.usedRegisters);
        info.patch.dfg.registersFlushed = m_propertyAccesses[i].m_registerMode == PropertyAccessRecord::RegistersFlushed;
    }
    for (unsigned i = 0; i < m_ins.size(); ++i) {
//.........这里部分代码省略.........

void JITCompiler::link(LinkBuffer& linkBuffer)
{
    // Link the code, populate data in CodeBlock data structures.
    m_jitCode->common.frameRegisterCount = m_graph.frameRegisterCount();
    m_jitCode->common.requiredRegisterCountForExit = m_graph.requiredRegisterCountForExit();

    if (!m_graph.m_inlineCallFrames->isEmpty())
        m_jitCode->common.inlineCallFrames = m_graph.m_inlineCallFrames.release();
    
    m_jitCode->common.machineCaptureStart = m_graph.m_machineCaptureStart;
    m_jitCode->common.slowArguments = std::move(m_graph.m_slowArguments);

    BitVector usedJumpTables;
    for (unsigned i = m_graph.m_switchData.size(); i--;) {
        SwitchData& data = m_graph.m_switchData[i];
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind == SwitchString)
            continue;
        
        RELEASE_ASSERT(data.kind == SwitchImm || data.kind == SwitchChar);
        
        usedJumpTables.set(data.switchTableIndex);
        SimpleJumpTable& table = m_codeBlock->switchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
        table.ctiOffsets.grow(table.branchOffsets.size());
        for (unsigned j = table.ctiOffsets.size(); j--;)
            table.ctiOffsets[j] = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            table.ctiOffsets[myCase.value.switchLookupValue() - table.min] =
                linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
        }
    }
    
    for (unsigned i = m_codeBlock->numberOfSwitchJumpTables(); i--;) {
        if (usedJumpTables.get(i))
            continue;
        
        m_codeBlock->switchJumpTable(i).clear();
    }

    // NOTE: we cannot clear string switch tables because (1) we're running concurrently
    // and we cannot deref StringImpl's and (2) it would be weird to deref those
    // StringImpl's since we refer to them.
    for (unsigned i = m_graph.m_switchData.size(); i--;) {
        SwitchData& data = m_graph.m_switchData[i];
        if (!data.didUseJumpTable)
            continue;
        
        if (data.kind != SwitchString)
            continue;
        
        StringJumpTable& table = m_codeBlock->stringSwitchJumpTable(data.switchTableIndex);
        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
        StringJumpTable::StringOffsetTable::iterator iter;
        StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
        for (iter = table.offsetTable.begin(); iter != end; ++iter)
            iter->value.ctiOffset = table.ctiDefault;
        for (unsigned j = data.cases.size(); j--;) {
            SwitchCase& myCase = data.cases[j];
            iter = table.offsetTable.find(myCase.value.stringImpl());
            RELEASE_ASSERT(iter != end);
            iter->value.ctiOffset = linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
        }
    }

    // Link all calls out from the JIT code to their respective functions.
    for (unsigned i = 0; i < m_calls.size(); ++i)
        linkBuffer.link(m_calls[i].m_call, m_calls[i].m_function);

    for (unsigned i = m_getByIds.size(); i--;)
        m_getByIds[i].finalize(linkBuffer);
    for (unsigned i = m_putByIds.size(); i--;)
        m_putByIds[i].finalize(linkBuffer);

    for (unsigned i = 0; i < m_ins.size(); ++i) {
        StructureStubInfo& info = *m_ins[i].m_stubInfo;
        CodeLocationLabel jump = linkBuffer.locationOf(m_ins[i].m_jump);
        CodeLocationCall callReturnLocation = linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->call());
        info.hotPathBegin = jump;
        info.callReturnLocation = callReturnLocation;
        info.patch.deltaCallToSlowCase = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->label()));
    }
    
    m_codeBlock->setNumberOfCallLinkInfos(m_jsCalls.size());
    for (unsigned i = 0; i < m_jsCalls.size(); ++i) {
        CallLinkInfo& info = m_codeBlock->callLinkInfo(i);
        info.callType = m_jsCalls[i].m_callType;
        info.isDFG = true;
        info.codeOrigin = m_jsCalls[i].m_codeOrigin;
        linkBuffer.link(m_jsCalls[i].m_slowCall, FunctionPtr((m_vm->getCTIStub(info.callType == CallLinkInfo::Construct ? linkConstructThunkGenerator : linkCallThunkGenerator)).code().executableAddress()));
        info.callReturnLocation = linkBuffer.locationOfNearCall(m_jsCalls[i].m_slowCall);
        info.hotPathBegin = linkBuffer.locationOf(m_jsCalls[i].m_targetToCheck);
        info.hotPathOther = linkBuffer.locationOfNearCall(m_jsCalls[i].m_fastCall);
        info.calleeGPR = static_cast<unsigned>(m_jsCalls[i].m_callee);
    }
    
    MacroAssemblerCodeRef osrExitThunk = vm()->getCTIStub(osrExitGenerationThunkGenerator);
//.........这里部分代码省略.........

    bool run()
    {
        // This enumerates the locals that we actually care about and packs them. So for example
        // if we use local 1, 3, 4, 5, 7, then we remap them: 1->0, 3->1, 4->2, 5->3, 7->4. We
        // treat a variable as being "used" if there exists an access to it (SetLocal, GetLocal,
        // Flush, PhantomLocal).
        
        BitVector usedLocals;
        
        // Collect those variables that are used from IR.
        bool hasNodesThatNeedFixup = false;
        for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
            BasicBlock* block = m_graph.block(blockIndex);
            if (!block)
                continue;
            for (unsigned nodeIndex = block->size(); nodeIndex--;) {
                Node* node = block->at(nodeIndex);
                switch (node->op()) {
                case GetLocal:
                case SetLocal:
                case Flush:
                case PhantomLocal: {
                    VariableAccessData* variable = node->variableAccessData();
                    if (variable->local().isArgument())
                        break;
                    usedLocals.set(variable->local().toLocal());
                    break;
                }
                    
                case GetLocalUnlinked: {
                    VirtualRegister operand = node->unlinkedLocal();
                    if (operand.isArgument())
                        break;
                    usedLocals.set(operand.toLocal());
                    hasNodesThatNeedFixup = true;
                    break;
                }
                    
                case LoadVarargs:
                case ForwardVarargs: {
                    LoadVarargsData* data = node->loadVarargsData();
                    if (data->count.isLocal())
                        usedLocals.set(data->count.toLocal());
                    if (data->start.isLocal()) {
                        // This part really relies on the contiguity of stack layout
                        // assignments.
                        ASSERT(VirtualRegister(data->start.offset() + data->limit - 1).isLocal());
                        for (unsigned i = data->limit; i--;) 
                            usedLocals.set(VirtualRegister(data->start.offset() + i).toLocal());
                    } // the else case shouldn't happen.
                    hasNodesThatNeedFixup = true;
                    break;
                }
                    
                case PutStack:
                case GetStack: {
                    StackAccessData* stack = node->stackAccessData();
                    if (stack->local.isArgument())
                        break;
                    usedLocals.set(stack->local.toLocal());
                    break;
                }
                    
                default:
                    break;
                }
            }
        }
        
        for (InlineCallFrameSet::iterator iter = m_graph.m_plan.inlineCallFrames->begin(); !!iter; ++iter) {
            InlineCallFrame* inlineCallFrame = *iter;
            
            if (inlineCallFrame->isVarargs()) {
                usedLocals.set(VirtualRegister(
                    JSStack::ArgumentCount + inlineCallFrame->stackOffset).toLocal());
            }
            
            for (unsigned argument = inlineCallFrame->arguments.size(); argument-- > 1;) {
                usedLocals.set(VirtualRegister(
                    virtualRegisterForArgument(argument).offset() +
                    inlineCallFrame->stackOffset).toLocal());
            }
        }
        
        Vector<unsigned> allocation(usedLocals.size());
        m_graph.m_nextMachineLocal = 0;
        for (unsigned i = 0; i < usedLocals.size(); ++i) {
            if (!usedLocals.get(i)) {
                allocation[i] = UINT_MAX;
                continue;
            }
            
            allocation[i] = m_graph.m_nextMachineLocal++;
        }
        
        for (unsigned i = m_graph.m_variableAccessData.size(); i--;) {
            VariableAccessData* variable = &m_graph.m_variableAccessData[i];
            if (!variable->isRoot())
                continue;
            
//.........这里部分代码省略.........

    bool run()
    {
        SharedSymbolTable* symbolTable = codeBlock()->symbolTable();

        // This enumerates the locals that we actually care about and packs them. So for example
        // if we use local 1, 3, 4, 5, 7, then we remap them: 1->0, 3->1, 4->2, 5->3, 7->4. We
        // treat a variable as being "used" if there exists an access to it (SetLocal, GetLocal,
        // Flush, PhantomLocal).
        
        BitVector usedLocals;
        
        // Collect those variables that are used from IR.
        bool hasGetLocalUnlinked = false;
        for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
            BasicBlock* block = m_graph.block(blockIndex);
            if (!block)
                continue;
            for (unsigned nodeIndex = block->size(); nodeIndex--;) {
                Node* node = block->at(nodeIndex);
                switch (node->op()) {
                case GetLocal:
                case SetLocal:
                case Flush:
                case PhantomLocal: {
                    VariableAccessData* variable = node->variableAccessData();
                    if (variable->local().isArgument())
                        break;
                    usedLocals.set(variable->local().toLocal());
                    break;
                }
                    
                case GetLocalUnlinked: {
                    VirtualRegister operand = node->unlinkedLocal();
                    if (operand.isArgument())
                        break;
                    usedLocals.set(operand.toLocal());
                    hasGetLocalUnlinked = true;
                    break;
                }
                    
                default:
                    break;
                }
            }
        }
        
        // Ensure that captured variables and captured inline arguments are pinned down.
        // They should have been because of flushes, except that the flushes can be optimized
        // away.
        if (symbolTable) {
            for (int i = symbolTable->captureStart(); i > symbolTable->captureEnd(); i--)
                usedLocals.set(VirtualRegister(i).toLocal());
        }
        if (codeBlock()->usesArguments()) {
            usedLocals.set(codeBlock()->argumentsRegister().toLocal());
            usedLocals.set(unmodifiedArgumentsRegister(codeBlock()->argumentsRegister()).toLocal());
        }
        if (codeBlock()->uncheckedActivationRegister().isValid())
            usedLocals.set(codeBlock()->activationRegister().toLocal());
        for (InlineCallFrameSet::iterator iter = m_graph.m_inlineCallFrames->begin(); !!iter; ++iter) {
            InlineCallFrame* inlineCallFrame = *iter;
            if (!inlineCallFrame->executable->usesArguments())
                continue;
            
            VirtualRegister argumentsRegister = m_graph.argumentsRegisterFor(inlineCallFrame);
            usedLocals.set(argumentsRegister.toLocal());
            usedLocals.set(unmodifiedArgumentsRegister(argumentsRegister).toLocal());
            
            for (unsigned argument = inlineCallFrame->arguments.size(); argument-- > 1;) {
                usedLocals.set(VirtualRegister(
                    virtualRegisterForArgument(argument).offset() +
                    inlineCallFrame->stackOffset).toLocal());
            }
        }
        
        Vector<unsigned> allocation(usedLocals.size());
        m_graph.m_nextMachineLocal = 0;
        for (unsigned i = 0; i < usedLocals.size(); ++i) {
            if (!usedLocals.get(i)) {
                allocation[i] = UINT_MAX;
                continue;
            }
            
            allocation[i] = m_graph.m_nextMachineLocal++;
        }
        
        for (unsigned i = m_graph.m_variableAccessData.size(); i--;) {
            VariableAccessData* variable = &m_graph.m_variableAccessData[i];
            if (!variable->isRoot())
                continue;
            
            if (variable->local().isArgument()) {
                variable->machineLocal() = variable->local();
                continue;
            }
            
            size_t local = variable->local().toLocal();
            if (local >= allocation.size())
                continue;
            
//.........这里部分代码省略.........