nodes.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

{
    NodeReleaser::releaseAllNodes(this);
}

void ReadModifyBracketNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_base);
    releaser.release(m_subscript);
    releaser.release(m_right);
}

RegisterID* ReadModifyBracketNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base.get(), m_subscriptHasAssignments || m_rightHasAssignments, m_subscript->isPure(generator) && m_right->isPure(generator));
    RefPtr<RegisterID> property = generator.emitNodeForLeftHandSide(m_subscript.get(), m_rightHasAssignments, m_right->isPure(generator));

    generator.emitExpressionInfo(divot() - m_subexpressionDivotOffset, startOffset() - m_subexpressionDivotOffset, m_subexpressionEndOffset);
    RefPtr<RegisterID> value = generator.emitGetByVal(generator.tempDestination(dst), base.get(), property.get());
    RegisterID* change = generator.emitNode(m_right.get());
    RegisterID* updatedValue = emitReadModifyAssignment(generator, generator.finalDestination(dst, value.get()), value.get(), change, m_operator, OperandTypes(ResultType::unknownType(), m_right->resultDescriptor()));

    generator.emitExpressionInfo(divot(), startOffset(), endOffset());
    generator.emitPutByVal(base.get(), property.get(), updatedValue);

    return updatedValue;
}

// ------------------------------ CommaNode ------------------------------------

CommaNode::~CommaNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void CommaNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_expr1);
    releaser.release(m_expr2);
}

RegisterID* CommaNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    generator.emitNode(generator.ignoredResult(), m_expr1.get());
    return generator.emitNode(dst, m_expr2.get());
}

// ------------------------------ ConstDeclNode ------------------------------------

ConstDeclNode::~ConstDeclNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void ConstDeclNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_next);
    releaser.release(m_init);
}

ConstDeclNode::ConstDeclNode(JSGlobalData* globalData, const Identifier& ident, ExpressionNode* init)
    : ExpressionNode(globalData)
    , m_ident(ident)
    , m_init(init)
{
}

RegisterID* ConstDeclNode::emitCodeSingle(BytecodeGenerator& generator)
{
    if (RegisterID* local = generator.constRegisterFor(m_ident)) {
        if (!m_init)
            return local;

        return generator.emitNode(local, m_init.get());
    }
    
    // FIXME: While this code should only be hit in eval code, it will potentially
    // assign to the wrong base if m_ident exists in an intervening dynamic scope.
    RefPtr<RegisterID> base = generator.emitResolveBase(generator.newTemporary(), m_ident);
    RegisterID* value = m_init ? generator.emitNode(m_init.get()) : generator.emitLoad(0, jsUndefined());
    return generator.emitPutById(base.get(), m_ident, value);
}

RegisterID* ConstDeclNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
{
    RegisterID* result = 0;
    for (ConstDeclNode* n = this; n; n = n->m_next.get())
        result = n->emitCodeSingle(generator);

    return result;
}

// ------------------------------ ConstStatementNode -----------------------------

ConstStatementNode::~ConstStatementNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void ConstStatementNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_next);
}

RegisterID* ConstStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
{
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    return generator.emitNode(m_next.get());
}

// ------------------------------ Helper functions for handling Vectors of StatementNode -------------------------------

static inline RegisterID* statementListEmitCode(const StatementVector& statements, BytecodeGenerator& generator, RegisterID* dst)
{
    StatementVector::const_iterator end = statements.end();
    for (StatementVector::const_iterator it = statements.begin(); it != end; ++it) {
        StatementNode* n = it->get();
        generator.emitNode(dst, n);
    }
    return 0;
}

// ------------------------------ BlockNode ------------------------------------

BlockNode::~BlockNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void BlockNode::releaseNodes(NodeReleaser& releaser)
{
    size_t size = m_children.size();
    for (size_t i = 0; i < size; ++i)
        releaser.release(m_children[i]);
}

BlockNode::BlockNode(JSGlobalData* globalData, SourceElements* children)
    : StatementNode(globalData)
{
    if (children)
        children->releaseContentsIntoVector(m_children);
}

RegisterID* BlockNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    return statementListEmitCode(m_children, generator, dst);
}

// ------------------------------ EmptyStatementNode ---------------------------

RegisterID* EmptyStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    return dst;
}

// ------------------------------ DebuggerStatementNode ---------------------------

RegisterID* DebuggerStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    generator.emitDebugHook(DidReachBreakpoint, firstLine(), lastLine());
    return dst;
}

// ------------------------------ ExprStatementNode ----------------------------

RegisterID* ExprStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    ASSERT(m_expr);
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine()); 
    return generator.emitNode(dst, m_expr.get());
}

// ------------------------------ VarStatementNode ----------------------------

VarStatementNode::~VarStatementNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void VarStatementNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_expr);
}

RegisterID* VarStatementNode::emitBytecode(BytecodeGenerator& generator, RegisterID*)
{
    ASSERT(m_expr);
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    return generator.emitNode(m_expr.get());
}

// ------------------------------ IfNode ---------------------------------------

IfNode::~IfNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void IfNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_condition);
    releaser.release(m_ifBlock);
}

RegisterID* IfNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    
    RefPtr<Label> afterThen = generator.newLabel();

    RegisterID* cond = generator.emitNode(m_condition.get());
    generator.emitJumpIfFalse(cond, afterThen.get());

    generator.emitNode(dst, m_ifBlock.get());
    generator.emitLabel(afterThen.get());

    // FIXME: This should return the last statement executed so that it can be returned as a Completion.
    return 0;
}

// ------------------------------ IfElseNode ---------------------------------------

IfElseNode::~IfElseNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void IfElseNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_elseBlock);
    IfNode::releaseNodes(releaser);
}

RegisterID* IfElseNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    
    RefPtr<Label> beforeElse = generator.newLabel();
    RefPtr<Label> afterElse = generator.newLabel();

    RegisterID* cond = generator.emitNode(m_condition.get());
    generator.emitJumpIfFalse(cond, beforeElse.get());

    generator.emitNode(dst, m_ifBlock.get());
    generator.emitJump(afterElse.get());

    generator.emitLabel(beforeElse.get());

    generator.emitNode(dst, m_elseBlock.get());

    generator.emitLabel(afterElse.get());

    // FIXME: This should return the last statement executed so that it can be returned as a Completion.
    return 0;
}

// ------------------------------ DoWhileNode ----------------------------------

DoWhileNode::~DoWhileNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void DoWhileNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_statement);
    releaser.release(m_expr);
}

RegisterID* DoWhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);

    RefPtr<Label> topOfLoop = generator.newLabel();
    generator.emitLabel(topOfLoop.get());

    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
   
    RefPtr<RegisterID> result = generator.emitNode(dst, m_statement.get());

    generator.emitLabel(scope->continueTarget());
    generator.emitDebugHook(WillExecuteStatement, m_expr->lineNo(), m_expr->lineNo());
    RegisterID* cond = generator.emitNode(m_expr.get());
    generator.emitJumpIfTrue(cond, topOfLoop.get());

    generator.emitLabel(scope->breakTarget());
    return result.get();
}

// ------------------------------ WhileNode ------------------------------------

WhileNode::~WhileNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void WhileNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_expr);
    releaser.release(m_statement);
}

RegisterID* WhileNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);

    generator.emitJump(scope->continueTarget());

    RefPtr<Label> topOfLoop = generator.newLabel();
    generator.emitLabel(topOfLoop.get());
    
    generator.emitNode(dst, m_statement.get());

    generator.emitLabel(scope->continueTarget());
    generator.emitDebugHook(WillExecuteStatement, m_expr->lineNo(), m_expr->lineNo());
    RegisterID* cond = generator.emitNode(m_expr.get());
    generator.emitJumpIfTrue(cond, topOfLoop.get());

    generator.emitLabel(scope->breakTarget());
    
    // FIXME: This should return the last statement executed so that it can be returned as a Completion
    return 0;
}

// ------------------------------ ForNode --------------------------------------

ForNode::~ForNode()
{
    NodeReleaser::releaseAllNodes(this);
}

void ForNode::releaseNodes(NodeReleaser& releaser)
{
    releaser.release(m_expr1);
    releaser.release(m_expr2);
    releaser.release(m_expr3);
    releaser.release(m_statement);
}

RegisterID* ForNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
{
    if (dst == generator.ignoredResult())
        dst = 0;

    RefPtr<LabelScope> scope = generator.newLabelScope(LabelScope::Loop);

    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());

    if (m_expr1)
        generator.emitNode(generator.ignoredResult(), m_expr1.get());

    RefPtr<Label> condition = generator.newLabel();
    generator.emitJump(condition.get());

    RefPtr<Label> topOfLoop = generator.newLabel();
    generator.emitLabel(topOfLoop.get());

    RefPtr<RegisterID> result = generator.emitNode(dst, m_statement.get());

    generator.emitLabel(scope->continueTarget());
    generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine());
    if (m_expr3)
        generator.emitNode(generator.ignoredResult(), m_expr3.get());

    generator.emitLabel(condition.get());
    if (m_expr2) {
        RegisterID* cond = generator.emitNode(m_expr2.get());
        generator.emitJumpIfTrue(cond, topOfLoop.get());