codeblock.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

    }
    if (vPC[0].u.opcode == interpreter->getOpcode(op_put_by_id_transition)) {
        vPC[4].u.structure->ref();
        vPC[5].u.structure->ref();
        vPC[6].u.structureChain->ref();
        return;
    }
    if (vPC[0].u.opcode == interpreter->getOpcode(op_put_by_id_replace)) {
        vPC[4].u.structure->ref();
        return;
    }
    
    // These instructions don't ref their Structures.
    ASSERT(vPC[0].u.opcode == interpreter->getOpcode(op_get_by_id) || vPC[0].u.opcode == interpreter->getOpcode(op_put_by_id) || vPC[0].u.opcode == interpreter->getOpcode(op_get_by_id_generic) || vPC[0].u.opcode == interpreter->getOpcode(op_put_by_id_generic));
}

void CodeBlock::mark()
{
    for (size_t i = 0; i < m_constantRegisters.size(); ++i)
        if (!m_constantRegisters[i].marked())
            m_constantRegisters[i].mark();

    for (size_t i = 0; i < m_functionExpressions.size(); ++i)
        m_functionExpressions[i]->body()->mark();

    if (m_rareData) {
        for (size_t i = 0; i < m_rareData->m_functions.size(); ++i)
            m_rareData->m_functions[i]->body()->mark();

        for (size_t i = 0; i < m_rareData->m_unexpectedConstants.size(); ++i) {
            if (!m_rareData->m_unexpectedConstants[i].marked())
                m_rareData->m_unexpectedConstants[i].mark();
        }
        m_rareData->m_evalCodeCache.mark();
    }
}

void CodeBlock::reparseForExceptionInfoIfNecessary(CallFrame* callFrame)
{
    if (m_exceptionInfo)
        return;

    ScopeChainNode* scopeChain = callFrame->scopeChain();
    if (m_needsFullScopeChain) {
        ScopeChain sc(scopeChain);
        int scopeDelta = sc.localDepth();
        if (m_codeType == EvalCode)
            scopeDelta -= static_cast<EvalCodeBlock*>(this)->baseScopeDepth();
        else if (m_codeType == FunctionCode)
            scopeDelta++; // Compilation of function code assumes activation is not on the scope chain yet.
        ASSERT(scopeDelta >= 0);
        while (scopeDelta--)
            scopeChain = scopeChain->next;
    }

    switch (m_codeType) {
        case FunctionCode: {
            FunctionBodyNode* ownerFunctionBodyNode = static_cast<FunctionBodyNode*>(m_ownerNode);
            RefPtr<FunctionBodyNode> newFunctionBody = m_globalData->parser->reparse<FunctionBodyNode>(m_globalData, ownerFunctionBodyNode);
            ASSERT(newFunctionBody);
            newFunctionBody->finishParsing(ownerFunctionBodyNode->copyParameters(), ownerFunctionBodyNode->parameterCount());

            m_globalData->scopeNodeBeingReparsed = newFunctionBody.get();

            CodeBlock& newCodeBlock = newFunctionBody->bytecodeForExceptionInfoReparse(scopeChain, this);
            ASSERT(newCodeBlock.m_exceptionInfo);
            ASSERT(newCodeBlock.m_instructionCount == m_instructionCount);

#if ENABLE(JIT)
            JIT::compile(m_globalData, &newCodeBlock);
            ASSERT(newCodeBlock.m_jitCode.codeSize == m_jitCode.codeSize);
#endif

            m_exceptionInfo.set(newCodeBlock.m_exceptionInfo.release());

            m_globalData->scopeNodeBeingReparsed = 0;

            break;
        }
        case EvalCode: {
            EvalNode* ownerEvalNode = static_cast<EvalNode*>(m_ownerNode);
            RefPtr<EvalNode> newEvalBody = m_globalData->parser->reparse<EvalNode>(m_globalData, ownerEvalNode);

            m_globalData->scopeNodeBeingReparsed = newEvalBody.get();

            EvalCodeBlock& newCodeBlock = newEvalBody->bytecodeForExceptionInfoReparse(scopeChain, this);
            ASSERT(newCodeBlock.m_exceptionInfo);
            ASSERT(newCodeBlock.m_instructionCount == m_instructionCount);

#if ENABLE(JIT)
            JIT::compile(m_globalData, &newCodeBlock);
            ASSERT(newCodeBlock.m_jitCode.codeSize == m_jitCode.codeSize);
#endif

            m_exceptionInfo.set(newCodeBlock.m_exceptionInfo.release());

            m_globalData->scopeNodeBeingReparsed = 0;

            break;
        }
        default:
            // CodeBlocks for Global code blocks are transient and therefore to not gain from 
            // from throwing out there exception information.
            ASSERT_NOT_REACHED();
    }
}

HandlerInfo* CodeBlock::handlerForBytecodeOffset(unsigned bytecodeOffset)
{
    ASSERT(bytecodeOffset < m_instructionCount);

    if (!m_rareData)
        return 0;
    
    Vector<HandlerInfo>& exceptionHandlers = m_rareData->m_exceptionHandlers;
    for (size_t i = 0; i < exceptionHandlers.size(); ++i) {
        // Handlers are ordered innermost first, so the first handler we encounter
        // that contains the source address is the correct handler to use.
        if (exceptionHandlers[i].start <= bytecodeOffset && exceptionHandlers[i].end >= bytecodeOffset)
            return &exceptionHandlers[i];
    }

    return 0;
}

int CodeBlock::lineNumberForBytecodeOffset(CallFrame* callFrame, unsigned bytecodeOffset)
{
    ASSERT(bytecodeOffset < m_instructionCount);

    reparseForExceptionInfoIfNecessary(callFrame);
    ASSERT(m_exceptionInfo);

    if (!m_exceptionInfo->m_lineInfo.size())
        return m_ownerNode->source().firstLine(); // Empty function

    int low = 0;
    int high = m_exceptionInfo->m_lineInfo.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_exceptionInfo->m_lineInfo[mid].instructionOffset <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }
    
    if (!low)
        return m_ownerNode->source().firstLine();
    return m_exceptionInfo->m_lineInfo[low - 1].lineNumber;
}

int CodeBlock::expressionRangeForBytecodeOffset(CallFrame* callFrame, unsigned bytecodeOffset, int& divot, int& startOffset, int& endOffset)
{
    ASSERT(bytecodeOffset < m_instructionCount);

    reparseForExceptionInfoIfNecessary(callFrame);
    ASSERT(m_exceptionInfo);

    if (!m_exceptionInfo->m_expressionInfo.size()) {
        // We didn't think anything could throw.  Apparently we were wrong.
        startOffset = 0;
        endOffset = 0;
        divot = 0;
        return lineNumberForBytecodeOffset(callFrame, bytecodeOffset);
    }

    int low = 0;
    int high = m_exceptionInfo->m_expressionInfo.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_exceptionInfo->m_expressionInfo[mid].instructionOffset <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }
    
    ASSERT(low);
    if (!low) {
        startOffset = 0;
        endOffset = 0;
        divot = 0;
        return lineNumberForBytecodeOffset(callFrame, bytecodeOffset);
    }

    startOffset = m_exceptionInfo->m_expressionInfo[low - 1].startOffset;
    endOffset = m_exceptionInfo->m_expressionInfo[low - 1].endOffset;
    divot = m_exceptionInfo->m_expressionInfo[low - 1].divotPoint + m_sourceOffset;
    return lineNumberForBytecodeOffset(callFrame, bytecodeOffset);
}

bool CodeBlock::getByIdExceptionInfoForBytecodeOffset(CallFrame* callFrame, unsigned bytecodeOffset, OpcodeID& opcodeID)
{
    ASSERT(bytecodeOffset < m_instructionCount);

    reparseForExceptionInfoIfNecessary(callFrame);
    ASSERT(m_exceptionInfo);        

    if (!m_exceptionInfo->m_getByIdExceptionInfo.size())
        return false;

    int low = 0;
    int high = m_exceptionInfo->m_getByIdExceptionInfo.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_exceptionInfo->m_getByIdExceptionInfo[mid].bytecodeOffset <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }

    if (!low || m_exceptionInfo->m_getByIdExceptionInfo[low - 1].bytecodeOffset != bytecodeOffset)
        return false;

    opcodeID = m_exceptionInfo->m_getByIdExceptionInfo[low - 1].isOpConstruct ? op_construct : op_instanceof;
    return true;
}

#if ENABLE(JIT)
bool CodeBlock::functionRegisterForBytecodeOffset(unsigned bytecodeOffset, int& functionRegisterIndex)
{
    ASSERT(bytecodeOffset < m_instructionCount);

    if (!m_rareData || !m_rareData->m_functionRegisterInfos.size())
        return false;

    int low = 0;
    int high = m_rareData->m_functionRegisterInfos.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_rareData->m_functionRegisterInfos[mid].bytecodeOffset <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }

    if (!low || m_rareData->m_functionRegisterInfos[low - 1].bytecodeOffset != bytecodeOffset)
        return false;

    functionRegisterIndex = m_rareData->m_functionRegisterInfos[low - 1].functionRegisterIndex;
    return true;
}
#endif

#if !ENABLE(JIT)
bool CodeBlock::hasGlobalResolveInstructionAtBytecodeOffset(unsigned bytecodeOffset)
{
    if (m_globalResolveInstructions.isEmpty())
        return false;

    int low = 0;
    int high = m_globalResolveInstructions.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_globalResolveInstructions[mid] <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }

    if (!low || m_globalResolveInstructions[low - 1] != bytecodeOffset)
        return false;
    return true;
}
#else
bool CodeBlock::hasGlobalResolveInfoAtBytecodeOffset(unsigned bytecodeOffset)
{
    if (m_globalResolveInfos.isEmpty())
        return false;

    int low = 0;
    int high = m_globalResolveInfos.size();
    while (low < high) {
        int mid = low + (high - low) / 2;
        if (m_globalResolveInfos[mid].bytecodeOffset <= bytecodeOffset)
            low = mid + 1;
        else
            high = mid;
    }

    if (!low || m_globalResolveInfos[low - 1].bytecodeOffset != bytecodeOffset)
        return false;
    return true;
}
#endif

#if ENABLE(JIT)
void CodeBlock::setJITCode(JITCodeRef& jitCode)
{
    m_jitCode = jitCode;
#if !ENABLE(OPCODE_SAMPLING)
    if (!BytecodeGenerator::dumpsGeneratedCode())
        m_instructions.clear();
#endif
}
#endif

void CodeBlock::shrinkToFit()
{
    m_instructions.shrinkToFit();

#if !ENABLE(JIT)
    m_propertyAccessInstructions.shrinkToFit();
    m_globalResolveInstructions.shrinkToFit();
#else
    m_structureStubInfos.shrinkToFit();
    m_globalResolveInfos.shrinkToFit();
    m_callLinkInfos.shrinkToFit();
    m_linkedCallerList.shrinkToFit();
#endif

    m_identifiers.shrinkToFit();
    m_functionExpressions.shrinkToFit();
    m_constantRegisters.shrinkToFit();

    if (m_exceptionInfo) {
        m_exceptionInfo->m_expressionInfo.shrinkToFit();
        m_exceptionInfo->m_lineInfo.shrinkToFit();
        m_exceptionInfo->m_getByIdExceptionInfo.shrinkToFit();
    }

    if (m_rareData) {
        m_rareData->m_exceptionHandlers.shrinkToFit();
        m_rareData->m_functions.shrinkToFit();
        m_rareData->m_unexpectedConstants.shrinkToFit();
        m_rareData->m_regexps.shrinkToFit();
        m_rareData->m_immediateSwitchJumpTables.shrinkToFit();
        m_rareData->m_characterSwitchJumpTables.shrinkToFit();
        m_rareData->m_stringSwitchJumpTables.shrinkToFit();
#if ENABLE(JIT)
        m_rareData->m_functionRegisterInfos.shrinkToFit();
#endif
    }
}

} // namespace JSC