import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public boolean enterCatchNode(final CatchNode catchNode) {
    enterDefault(catchNode);

    type("CatchClause");
    comma();

    property("param");
    catchNode.getException().accept(this);
    comma();

    final Node guard = catchNode.getExceptionCondition();
    if (guard != null) {
        property("guard");
        guard.accept(this);
        comma();
    }

    property("body");
    catchNode.getBody().accept(this);

    return leave();
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveForNode(final ForNode forNode) {
    ForNode newForNode = forNode;

    final Expression test = forNode.getTest();
    if (!forNode.isForIn() && isAlwaysTrue(test)) {
        newForNode = forNode.setTest(lc, null);
    }

    newForNode = checkEscape(newForNode);
    if(newForNode.isForIn()) {
        // Wrap it in a block so its internally created iterator is restricted in scope
        addStatementEnclosedInBlock(newForNode);
    } else {
        addStatement(newForNode);
    }
    return newForNode;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public <T extends Node> T pop(final T node) {
    final T popped = super.pop(node);
    if (isWithBoundary(node)) {
        dynamicScopeCount--;
        assert dynamicScopeCount >= 0;
    } else if (node instanceof FunctionNode) {
        if (((FunctionNode)node).inDynamicContext()) {
            dynamicScopeCount--;
            assert dynamicScopeCount >= 0;
        }
        assert splitNodes.peek() == 0;
        splitNodes.pop();
    }
    return popped;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveExpressionStatement(final ExpressionStatement expressionStatement) {
    final Expression expr = expressionStatement.getExpression();
    ExpressionStatement node = expressionStatement;

    final FunctionNode currentFunction = lc.getCurrentFunction();

    if (currentFunction.isProgram()) {
        if (!isInternalExpression(expr) && !isEvalResultAssignment(expr)) {
            node = expressionStatement.setExpression(
                new BinaryNode(
                    Token.recast(
                        expressionStatement.getToken(),
                        TokenType.ASSIGN),
                    compilerConstant(RETURN),
                expr));
        }
    }

    if (es6 && expressionStatement.destructuringDeclarationType() != null) {
        throwNotImplementedYet("es6.destructuring", expressionStatement);
    }

    return addStatement(node);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveIdentNode(final IdentNode identNode) {
    if (identNode.isPropertyName()) {
        return identNode;
    }

    final Symbol symbol = nameIsUsed(identNode.getName(), identNode);

    if (!identNode.isInitializedHere()) {
        symbol.increaseUseCount();
    }

    IdentNode newIdentNode = identNode.setSymbol(symbol);

    // If a block-scoped var is used before its declaration mark it as dead.
    // We can only statically detect this for local vars, cross-function symbols require runtime checks.
    if (symbol.isBlockScoped() && !symbol.hasBeenDeclared() && !identNode.isDeclaredHere() && isLocal(lc.getCurrentFunction(), symbol)) {
        newIdentNode = newIdentNode.markDead();
    }

    return end(newIdentNode);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
private boolean start(final Node node, final boolean printNode) {
    if (debug) {
        final StringBuilder sb = new StringBuilder();

        sb.append("[ENTER ").
            append(name(node)).
            append("] ").
            append(printNode ? node.toString() : "").
            append(" in '").
            append(lc.getCurrentFunction().getName()).
            append("'");
        log.info(sb);
        log.indent();
    }

    return true;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
private Node leaveTYPEOF(final UnaryNode unaryNode) {
    final Expression rhs = unaryNode.getExpression();

    final List<Expression> args = new ArrayList<>();
    if (rhs instanceof IdentNode && !isParamOrVar((IdentNode)rhs)) {
        args.add(compilerConstantIdentifier(SCOPE));
        args.add(LiteralNode.newInstance(rhs, ((IdentNode)rhs).getName())); //null
    } else {
        args.add(rhs);
        args.add(LiteralNode.newInstance(unaryNode)); //null, do not reuse token of identifier rhs, it can be e.g. 'this'
    }

    final Node runtimeNode = new RuntimeNode(unaryNode, Request.TYPEOF, args);

    end(unaryNode);

    return runtimeNode;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveForNode(final ForNode forNode) {
    ForNode newForNode = forNode;

    final Expression test = forNode.getTest();
    if (!forNode.isForInOrOf() && isAlwaysTrue(test)) {
        newForNode = forNode.setTest(lc, null);
    }

    newForNode = checkEscape(newForNode);
    if(!es6 && newForNode.isForInOrOf()) {
        // Wrap it in a block so its internally created iterator is restricted in scope, unless we are running
        // in ES6 mode, in which case the parser already created a block to capture let/const declarations.
        addStatementEnclosedInBlock(newForNode);
    } else {
        addStatement(newForNode);
    }
    return newForNode;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveIdentNode(final IdentNode identNode) {
    if(identNode.isPropertyName()) {
        return identNode;
    }
    return setProgramPoint(identNode);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
private static boolean isNumericArray(final Node[] values) {
    for (final Node node : values) {
        if (node instanceof LiteralNode && ((LiteralNode<?>)node).getValue() instanceof Number) {
            continue;
        }
        return false;
    }
    return true;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
private <T extends Node> T end(final T node, final boolean printNode) {
    if (debug) {
        final StringBuilder sb = new StringBuilder();

        sb.append("[LEAVE ").
            append(name(node)).
            append("] ").
            append(printNode ? node.toString() : "").
            append(" in '").
            append(lc.getCurrentFunction().getName()).
            append('\'');

        if (node instanceof IdentNode) {
            final Symbol symbol = ((IdentNode)node).getSymbol();
            if (symbol == null) {
                sb.append(" <NO SYMBOL>");
            } else {
                sb.append(" <symbol=").append(symbol).append('>');
            }
        }

        log.unindent();
        log.info(sb);
    }

    return node;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveLiteralNode(final LiteralNode<?> literalNode) {
    //for e.g. ArrayLiteralNodes the initial types may have been narrowed due to the
    //introduction of optimistic behavior - hence ensure that all literal nodes are
    //reinitialized
    return literalNode.initialize(lc);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveCaseNode(final CaseNode caseNode) {
    // Try to represent the case test as an integer
    final Node test = caseNode.getTest();
    if (test instanceof LiteralNode) {
        final LiteralNode<?> lit = (LiteralNode<?>)test;
        if (lit.isNumeric() && !(lit.getValue() instanceof Integer)) {
            if (JSType.isRepresentableAsInt(lit.getNumber())) {
                return caseNode.setTest((Expression)LiteralNode.newInstance(lit, lit.getInt32()).accept(this));
            }
        }
    }
    return caseNode;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveTernaryNode(final TernaryNode ternaryNode) {
    final Node test = ternaryNode.getTest();
    if (test instanceof LiteralNode.PrimitiveLiteralNode) {
        return (((LiteralNode.PrimitiveLiteralNode<?>)test).isTrue() ? ternaryNode.getTrueExpression() : ternaryNode.getFalseExpression()).getExpression();
    }
    return ternaryNode;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
protected boolean enterDefault(final Node node) {
    objectStart();
    location(node);

    return true;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@Override
public Node leaveIndexNode(final IndexNode indexNode) {
    final String name = getConstantPropertyName(indexNode.getIndex());
    if (name != null) {
        // If index node is a constant property name convert index node to access node.
        assert indexNode.isIndex();
        return new AccessNode(indexNode.getToken(), indexNode.getFinish(), indexNode.getBase(), name);
    }
    return super.leaveIndexNode(indexNode);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
@SuppressWarnings("rawtypes")
@Override
public boolean enterLiteralNode(final LiteralNode literalNode) {
    weight += LITERAL_WEIGHT;

    if (literalNode instanceof ArrayLiteralNode) {
        final ArrayLiteralNode arrayLiteralNode = (ArrayLiteralNode)literalNode;
        final Node[]           value            = arrayLiteralNode.getValue();
        final int[]            postsets         = arrayLiteralNode.getPostsets();
        final List<Splittable.SplitRange>  units            = arrayLiteralNode.getSplitRanges();

        if (units == null) {
            for (final int postset : postsets) {
                weight += AASTORE_WEIGHT;
                final Node element = value[postset];

                if (element != null) {
                    element.accept(this);
                }
            }
        }

        return false;
    }

    return true;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
/**
 * Is this an assignment to the special variable that hosts scripting eval
 * results, i.e. __return__?
 *
 * @param expression expression to check whether it is $evalresult = X
 * @return true if an assignment to eval result, false otherwise
 */
private static boolean isEvalResultAssignment(final Node expression) {
    final Node e = expression;
    if (e instanceof BinaryNode) {
        final Node lhs = ((BinaryNode)e).lhs();
        if (lhs instanceof IdentNode) {
            return ((IdentNode)lhs).getName().equals(RETURN.symbolName());
        }
    }
    return false;
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
/**
 * Try to do the apply to call transformation
 * @return true if successful, false otherwise
 */
@Override
public Node leaveFunctionNode(final FunctionNode functionNode) {
    FunctionNode newFunctionNode = functionNode;
    final String functionName = newFunctionNode.getName();

    if (changed.contains(newFunctionNode.getId())) {
        newFunctionNode = newFunctionNode.clearFlag(lc, FunctionNode.USES_ARGUMENTS).
                setFlag(lc, FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION).
                setParameters(lc, explodedArguments.peek());

        if (log.isEnabled()) {
            log.info("Success: ",
                    massageURL(newFunctionNode.getSource().getURL()),
                    '.',
                    functionName,
                    "' id=",
                    newFunctionNode.getId(),
                    " params=",
                    callSiteTypes.peek());
        }
    }

    callSiteTypes.pop();
    explodedArguments.pop();

    return newFunctionNode.setState(lc, CompilationState.BUILTINS_TRANSFORMED);
}
 

import jdk.nashorn.internal.ir.Node; //导入依赖的package包/类
private Node leaveASSIGN(final BinaryNode binaryNode) {
    // If we're assigning a property of the this object ("this.foo = ..."), record it.
    final Expression lhs = binaryNode.lhs();
    if (lhs instanceof AccessNode) {
        final AccessNode accessNode = (AccessNode) lhs;
        final Expression base = accessNode.getBase();
        if (base instanceof IdentNode) {
            final Symbol symbol = ((IdentNode)base).getSymbol();
            if(symbol.isThis()) {
                thisProperties.peek().add(accessNode.getProperty());
            }
        }
    }
    return binaryNode;
}