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Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically embedded into Java applications to provide scripting to end users.

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/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Norris Boyd
 *   Igor Bukanov
 *   Ethan Hugg
 *   Terry Lucas
 *   Milen Nankov
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript;

/**
 * This class allows the creation of nodes, and follows the Factory pattern.
 *
 * @see Node
 * @author Mike McCabe
 * @author Norris Boyd
 */
final class IRFactory
{
    IRFactory(Parser parser)
    {
        this.parser = parser;
    }

    ScriptOrFnNode createScript()
    {
        return new ScriptOrFnNode(Token.SCRIPT);
    }

    /**
     * Script (for associating file/url names with toplevel scripts.)
     */
    void initScript(ScriptOrFnNode scriptNode, Node body)
    {
        Node children = body.getFirstChild();
        if (children != null) { scriptNode.addChildrenToBack(children); }
    }

    /**
     * Leaf
     */
    Node createLeaf(int nodeType)
    {
        return new Node(nodeType);
    }

    Node createLeaf(int nodeType, int nodeOp)
    {
        return new Node(nodeType, nodeOp);
    }

    /**
     * Statement leaf nodes.
     */

    Node createSwitch(Node expr, int lineno)
    {
        //
        // The switch will be rewritten from:
        //
        // switch (expr) {
        //   case test1: statements1;
        //   ...
        //   default: statementsDefault;
        //   ...
        //   case testN: statementsN;
        // }
        //
        // to:
        //
        // {
        //     switch (expr) {
        //       case test1: goto label1;
        //       ...
        //       case testN: goto labelN;
        //     }
        //     goto labelDefault;
        //   label1:
        //     statements1;
        //   ...
        //   labelDefault:
        //     statementsDefault;
        //   ...
        //   labelN:
        //     statementsN;
        //   breakLabel:
        // }
        //
        // where inside switch each "break;" without label will be replaced
        // by "goto breakLabel".
        //
        // If the original switch does not have the default label, then
        // the transformed code would contain after the switch instead of
        //     goto labelDefault;
        // the following goto:
        //     goto breakLabel;
        //

        Node.Jump switchNode = new Node.Jump(Token.SWITCH, expr, lineno);
        Node block = new Node(Token.BLOCK, switchNode);
        return block;
    }

    /**
     * If caseExpression argument is null it indicate default label.
     */
    void addSwitchCase(Node switchBlock, Node caseExpression, Node statements)
    {
        if (switchBlock.getType() != Token.BLOCK) throw Kit.codeBug();
        Node.Jump switchNode = (Node.Jump)switchBlock.getFirstChild();
        if (switchNode.getType() != Token.SWITCH) throw Kit.codeBug();

        Node gotoTarget = Node.newTarget();
        if (caseExpression != null) {
            Node.Jump caseNode = new Node.Jump(Token.CASE, caseExpression);
            caseNode.target = gotoTarget;
            switchNode.addChildToBack(caseNode);
        } else {
            switchNode.setDefault(gotoTarget);
        }
        switchBlock.addChildToBack(gotoTarget);
        switchBlock.addChildToBack(statements);
    }

    void closeSwitch(Node switchBlock)
    {
        if (switchBlock.getType() != Token.BLOCK) throw Kit.codeBug();
        Node.Jump switchNode = (Node.Jump)switchBlock.getFirstChild();
        if (switchNode.getType() != Token.SWITCH) throw Kit.codeBug();

        Node switchBreakTarget = Node.newTarget();
        // switchNode.target is only used by NodeTransformer
        // to detect switch end
        switchNode.target = switchBreakTarget;

        Node defaultTarget = switchNode.getDefault();
        if (defaultTarget == null) {
            defaultTarget = switchBreakTarget;
        }

        switchBlock.addChildAfter(makeJump(Token.GOTO, defaultTarget),
                                  switchNode);
        switchBlock.addChildToBack(switchBreakTarget);
    }

    Node createVariables(int lineno)
    {
        return new Node(Token.VAR, lineno);
    }

    Node createExprStatement(Node expr, int lineno)
    {
        int type;
        if (parser.insideFunction()) {
            type = Token.EXPR_VOID;
        } else {
            type = Token.EXPR_RESULT;
        }
        return new Node(type, expr, lineno);
    }

    Node createExprStatementNoReturn(Node expr, int lineno)
    {
        return new Node(Token.EXPR_VOID, expr, lineno);
    }

    Node createDefaultNamespace(Node expr, int lineno)
    {
        // default xml namespace requires activation
        setRequiresActivation();
        Node n = createUnary(Token.DEFAULTNAMESPACE, expr);
        Node result = createExprStatement(n, lineno);
        return result;
    }

    /**
     * Name
     */
    Node createName(String name)
    {
        checkActivationName(name, Token.NAME);
        return Node.newString(Token.NAME, name);
    }

    /**
     * String (for literals)
     */
    Node createString(String string)
    {
        return Node.newString(string);
    }

    /**
     * Number (for literals)
     */
    Node createNumber(double number)
    {
        return Node.newNumber(number);
    }

    /**
     * Catch clause of try/catch/finally
     * @param varName the name of the variable to bind to the exception
     * @param catchCond the condition under which to catch the exception.
     *                  May be null if no condition is given.
     * @param stmts the statements in the catch clause
     * @param lineno the starting line number of the catch clause
     */
    Node createCatch(String varName, Node catchCond, Node stmts, int lineno)
    {
        if (catchCond == null) {
            catchCond = new Node(Token.EMPTY);
        }
        return new Node(Token.CATCH, createName(varName),
                        catchCond, stmts, lineno);
    }

    /**
     * Throw
     */
    Node createThrow(Node expr, int lineno)
    {
        return new Node(Token.THROW, expr, lineno);
    }

    /**
     * Return
     */
    Node createReturn(Node expr, int lineno)
    {
        return expr == null
            ? new Node(Token.RETURN, lineno)
            : new Node(Token.RETURN, expr, lineno);
    }

    /**
     * Label
     */
    Node createLabel(int lineno)
    {
        return new Node.Jump(Token.LABEL, lineno);
    }

    Node getLabelLoop(Node label)
    {
        return ((Node.Jump)label).getLoop();
    }

    /**
     * Label
     */
    Node createLabeledStatement(Node labelArg, Node statement)
    {
        Node.Jump label = (Node.Jump)labelArg;

        // Make a target and put it _after_ the statement
        // node.  And in the LABEL node, so breaks get the
        // right target.

        Node breakTarget = Node.newTarget();
        Node block = new Node(Token.BLOCK, label, statement, breakTarget);
        label.target = breakTarget;

        return block;
    }

    /**
     * Break (possibly labeled)
     */
    Node createBreak(Node breakStatement, int lineno)
    {
        Node.Jump n = new Node.Jump(Token.BREAK, lineno);
        Node.Jump jumpStatement;
        int t = breakStatement.getType();
        if (t == Token.LOOP || t == Token.LABEL) {
            jumpStatement = (Node.Jump)breakStatement;
        } else if (t == Token.BLOCK
                   && breakStatement.getFirstChild().getType() == Token.SWITCH)
        {
            jumpStatement = (Node.Jump)breakStatement.getFirstChild();
        } else {
            throw Kit.codeBug();
        }
        n.setJumpStatement(jumpStatement);
        return n;
    }

    /**
     * Continue (possibly labeled)
     */
    Node createContinue(Node loop, int lineno)
    {
        if (loop.getType() != Token.LOOP) Kit.codeBug();
        Node.Jump n = new Node.Jump(Token.CONTINUE, lineno);
        n.setJumpStatement((Node.Jump)loop);
        return n;
    }

    /**
     * Statement block
     * Creates the empty statement block
     * Must make subsequent calls to add statements to the node
     */
    Node createBlock(int lineno)
    {
        return new Node(Token.BLOCK, lineno);
    }

    FunctionNode createFunction(String name)
    {
        return new FunctionNode(name);
    }

    Node initFunction(FunctionNode fnNode, int functionIndex,
                      Node statements, int functionType)
    {
        fnNode.itsFunctionType = functionType;
        fnNode.addChildToBack(statements);

        int functionCount = fnNode.getFunctionCount();
        if (functionCount != 0) {
            // Functions containing other functions require activation objects
            fnNode.itsNeedsActivation = true;
            for (int i = 0; i != functionCount; ++i) {
                FunctionNode fn = fnNode.getFunctionNode(i);
                // nested function expression statements overrides var
                if (fn.getFunctionType()
                        == FunctionNode.FUNCTION_EXPRESSION_STATEMENT)
                {
                    String name = fn.getFunctionName();
                    if (name != null && name.length() != 0) {
                        fnNode.removeParamOrVar(name);
                    }
                }
            }
        }

        if (functionType == FunctionNode.FUNCTION_EXPRESSION) {
            String name = fnNode.getFunctionName();
            if (name != null && name.length() != 0
                && !fnNode.hasParamOrVar(name))
            {
                // A function expression needs to have its name as a
                // variable (if it isn't already allocated as a variable).
                // See ECMA Ch. 13.  We add code to the beginning of the
                // function to initialize a local variable of the
                // function's name to the function value.
                fnNode.addVar(name);
                Node setFn = new Node(Token.EXPR_VOID,
                                 new Node(Token.SETNAME,
                                     Node.newString(Token.BINDNAME, name),
                                     new Node(Token.THISFN)));
                statements.addChildrenToFront(setFn);
            }
        }

        // Add return to end if needed.
        Node lastStmt = statements.getLastChild();
        if (lastStmt == null || lastStmt.getType() != Token.RETURN) {
            statements.addChildToBack(new Node(Token.RETURN));
        }

        Node result = Node.newString(Token.FUNCTION,
                                     fnNode.getFunctionName());
        result.putIntProp(Node.FUNCTION_PROP, functionIndex);
        return result;
    }

    /**
     * Add a child to the back of the given node.  This function
     * breaks the Factory abstraction, but it removes a requirement
     * from implementors of Node.
     */
    void addChildToBack(Node parent, Node child)
    {
        parent.addChildToBack(child);
    }

    /**
     * Create loop node. The parser will later call
     * createWhile|createDoWhile|createFor|createForIn
     * to finish loop generation.
     */
    Node createLoopNode(Node loopLabel, int lineno)
    {
        Node.Jump result = new Node.Jump(Token.LOOP, lineno);
        if (loopLabel != null) {
            ((Node.Jump)loopLabel).setLoop(result);
        }
        return result;
    }

    /**
     * While
     */
    Node createWhile(Node loop, Node cond, Node body)
    {
        return createLoop((Node.Jump)loop, LOOP_WHILE, body, cond,
                          null, null);
    }

    /**
     * DoWhile
     */
    Node createDoWhile(Node loop, Node body, Node cond)
    {
        return createLoop((Node.Jump)loop, LOOP_DO_WHILE, body, cond,
                          null, null);
    }

    /**
     * For
     */
    Node createFor(Node loop, Node init, Node test, Node incr, Node body)
    {
        return createLoop((Node.Jump)loop, LOOP_FOR, body, test,
                          init, incr);
    }

    private Node createLoop(Node.Jump loop, int loopType, Node body, Node cond,
                            Node init, Node incr)
    {
        Node bodyTarget = Node.newTarget();
        Node condTarget = Node.newTarget();
        if (loopType == LOOP_FOR && cond.getType() == Token.EMPTY) {
            cond = new Node(Token.TRUE);
        }
        Node.Jump IFEQ = new Node.Jump(Token.IFEQ, cond);
        IFEQ.target = bodyTarget;
        Node breakTarget = Node.newTarget();

        loop.addChildToBack(bodyTarget);
        loop.addChildrenToBack(body);
        if (loopType == LOOP_WHILE || loopType == LOOP_FOR) {
            // propagate lineno to condition
            loop.addChildrenToBack(new Node(Token.EMPTY, loop.getLineno()));
        }
        loop.addChildToBack(condTarget);
        loop.addChildToBack(IFEQ);
        loop.addChildToBack(breakTarget);

        loop.target = breakTarget;
        Node continueTarget = condTarget;

        if (loopType == LOOP_WHILE || loopType == LOOP_FOR) {
            // Just add a GOTO to the condition in the do..while
            loop.addChildToFront(makeJump(Token.GOTO, condTarget));

            if (loopType == LOOP_FOR) {
                if (init.getType() != Token.EMPTY) {
                    if (init.getType() != Token.VAR) {
                        init = new Node(Token.EXPR_VOID, init);
                    }
                    loop.addChildToFront(init);
                }
                Node incrTarget = Node.newTarget();
                loop.addChildAfter(incrTarget, body);
                if (incr.getType() != Token.EMPTY) {
                    incr = new Node(Token.EXPR_VOID, incr);
                    loop.addChildAfter(incr, incrTarget);
                }
                continueTarget = incrTarget;
            }
        }

        loop.setContinue(continueTarget);

        return loop;
    }

    /**
     * For .. In
     *
     */
    Node createForIn(Node loop, Node lhs, Node obj, Node body,
                     boolean isForEach)
    {
        String name;
        int type = lhs.getType();

        Node lvalue;
        if (type == Token.VAR) {
            /*
             * check that there was only one variable given.
             * we can't do this in the parser, because then the
             * parser would have to know something about the
             * 'init' node of the for-in loop.
             */
            Node lastChild = lhs.getLastChild();
            if (lhs.getFirstChild() != lastChild) {
                parser.reportError("msg.mult.index");
            }
            lvalue = Node.newString(Token.NAME, lastChild.getString());
        } else {
            lvalue = makeReference(lhs);
            if (lvalue == null) {
                parser.reportError("msg.bad.for.in.lhs");
                return obj;
            }
        }

        Node localBlock = new Node(Token.LOCAL_BLOCK);

        int initType = (isForEach) ? Token.ENUM_INIT_VALUES
                                   : Token.ENUM_INIT_KEYS;
        Node init = new Node(initType, obj);
        init.putProp(Node.LOCAL_BLOCK_PROP, localBlock);
        Node cond = new Node(Token.ENUM_NEXT);
        cond.putProp(Node.LOCAL_BLOCK_PROP, localBlock);
        Node id = new Node(Token.ENUM_ID);
        id.putProp(Node.LOCAL_BLOCK_PROP, localBlock);

        Node newBody = new Node(Token.BLOCK);
        Node assign = simpleAssignment(lvalue, id);
        newBody.addChildToBack(new Node(Token.EXPR_VOID, assign));
        newBody.addChildToBack(body);

        loop = createWhile(loop, cond, newBody);
        loop.addChildToFront(init);
        if (type == Token.VAR)
            loop.addChildToFront(lhs);
        localBlock.addChildToBack(loop);

        return localBlock;
    }

    /**
     * Try/Catch/Finally
     *
     * The IRFactory tries to express as much as possible in the tree;
     * the responsibilities remaining for Codegen are to add the Java
     * handlers: (Either (but not both) of TARGET and FINALLY might not
     * be defined)

     * - a catch handler for javascript exceptions that unwraps the
     * exception onto the stack and GOTOes to the catch target

     * - a finally handler

     * ... and a goto to GOTO around these handlers.
     */
    Node createTryCatchFinally(Node tryBlock, Node catchBlocks,
                               Node finallyBlock, int lineno)
    {
        boolean hasFinally = (finallyBlock != null)
                             && (finallyBlock.getType() != Token.BLOCK
                                 || finallyBlock.hasChildren());

        // short circuit
        if (tryBlock.getType() == Token.BLOCK && !tryBlock.hasChildren()
            && !hasFinally)
        {
            return tryBlock;
        }

        boolean hasCatch = catchBlocks.hasChildren();

        // short circuit
        if (!hasFinally && !hasCatch)  {
            // bc finally might be an empty block...
            return tryBlock;
        }


        Node handlerBlock  = new Node(Token.LOCAL_BLOCK);
        Node.Jump pn = new Node.Jump(Token.TRY, tryBlock, lineno);
        pn.putProp(Node.LOCAL_BLOCK_PROP, handlerBlock);

        if (hasCatch) {
            // jump around catch code
            Node endCatch = Node.newTarget();
            pn.addChildToBack(makeJump(Token.GOTO, endCatch));

            // make a TARGET for the catch that the tcf node knows about
            Node catchTarget = Node.newTarget();
            pn.target = catchTarget;
            // mark it
            pn.addChildToBack(catchTarget);

            //
            //  Given
            //
            //   try {
            //       tryBlock;
            //   } catch (e if condition1) {
            //       something1;
            //   ...
            //
            //   } catch (e if conditionN) {
            //       somethingN;
            //   } catch (e) {
            //       somethingDefault;
            //   }
            //
            //  rewrite as
            //
            //   try {
            //       tryBlock;
            //       goto after_catch:
            //   } catch (x) {
            //       with (newCatchScope(e, x)) {
            //           if (condition1) {
            //               something1;
            //               goto after_catch;
            //           }
            //       }
            //   ...
            //       with (newCatchScope(e, x)) {
            //           if (conditionN) {
            //               somethingN;
            //               goto after_catch;
            //           }
            //       }
            //       with (newCatchScope(e, x)) {
            //           somethingDefault;
            //           goto after_catch;
            //       }
            //   }
            // after_catch:
            //
            // If there is no default catch, then the last with block
            // arround  "somethingDefault;" is replaced by "rethrow;"

            // It is assumed that catch handler generation will store
            // exeception object in handlerBlock register

            // Block with local for exception scope objects
            Node catchScopeBlock = new Node(Token.LOCAL_BLOCK);

            // expects catchblocks children to be (cond block) pairs.
            Node cb = catchBlocks.getFirstChild();
            boolean hasDefault = false;
            int scopeIndex = 0;
            while (cb != null) {
                int catchLineNo = cb.getLineno();

                Node name = cb.getFirstChild();
                Node cond = name.getNext();
                Node catchStatement = cond.getNext();
                cb.removeChild(name);
                cb.removeChild(cond);
                cb.removeChild(catchStatement);

                // Add goto to the catch statement to jump out of catch
                // but prefix it with LEAVEWITH since try..catch produces
                // "with"code in order to limit the scope of the exception
                // object.
                catchStatement.addChildToBack(new Node(Token.LEAVEWITH));
                catchStatement.addChildToBack(makeJump(Token.GOTO, endCatch));

                // Create condition "if" when present
                Node condStmt;
                if (cond.getType() == Token.EMPTY) {
                    condStmt = catchStatement;
                    hasDefault = true;
                } else {
                    condStmt = createIf(cond, catchStatement, null,
                                        catchLineNo);
                }

                // Generate code to create the scope object and store
                // it in catchScopeBlock register
                Node catchScope = new Node(Token.CATCH_SCOPE, name,
                                           createUseLocal(handlerBlock));
                catchScope.putProp(Node.LOCAL_BLOCK_PROP, catchScopeBlock);
                catchScope.putIntProp(Node.CATCH_SCOPE_PROP, scopeIndex);
                catchScopeBlock.addChildToBack(catchScope);

                // Add with statement based on catch scope object
                catchScopeBlock.addChildToBack(
                    createWith(createUseLocal(catchScopeBlock), condStmt,
                               catchLineNo));

                // move to next cb
                cb = cb.getNext();
                ++scopeIndex;
            }
            pn.addChildToBack(catchScopeBlock);
            if (!hasDefault) {
                // Generate code to rethrow if no catch clause was executed
                Node rethrow = new Node(Token.RETHROW);
                rethrow.putProp(Node.LOCAL_BLOCK_PROP, handlerBlock);
                pn.addChildToBack(rethrow);
            }

            pn.addChildToBack(endCatch);
        }

        if (hasFinally) {
            Node finallyTarget = Node.newTarget();
            pn.setFinally(finallyTarget);

            // add jsr finally to the try block
            pn.addChildToBack(makeJump(Token.JSR, finallyTarget));

            // jump around finally code
            Node finallyEnd = Node.newTarget();
            pn.addChildToBack(makeJump(Token.GOTO, finallyEnd));

            pn.addChildToBack(finallyTarget);
            Node fBlock = new Node(Token.FINALLY, finallyBlock);
            fBlock.putProp(Node.LOCAL_BLOCK_PROP, handlerBlock);
            pn.addChildToBack(fBlock);

            pn.addChildToBack(finallyEnd);
        }
        handlerBlock.addChildToBack(pn);
        return handlerBlock;
    }

    /**
     * Throw, Return, Label, Break and Continue are defined in ASTFactory.
     */

    /**
     * With
     */
    Node createWith(Node obj, Node body, int lineno)
    {
        setRequiresActivation();
        Node result = new Node(Token.BLOCK, lineno);
        result.addChildToBack(new Node(Token.ENTERWITH, obj));
        Node bodyNode = new Node(Token.WITH, body, lineno);
        result.addChildrenToBack(bodyNode);
        result.addChildToBack(new Node(Token.LEAVEWITH));
        return result;
    }

    /**
     * DOTQUERY
     */
    public Node createDotQuery (Node obj, Node body, int lineno)
    {
        setRequiresActivation();
        Node result = new Node(Token.DOTQUERY, obj, body, lineno);
        return result;
    }

    Node createArrayLiteral(ObjArray elems, int skipCount)
    {
        int length = elems.size();
        int[] skipIndexes = null;
        if (skipCount != 0) {
            skipIndexes = new int[skipCount];
        }
        Node array = new Node(Token.ARRAYLIT);
        for (int i = 0, j = 0; i != length; ++i) {
            Node elem = (Node)elems.get(i);
            if (elem != null) {
                array.addChildToBack(elem);
            } else {
                skipIndexes[j] = i;
                ++j;
            }
        }
        if (skipCount != 0) {
            array.putProp(Node.SKIP_INDEXES_PROP, skipIndexes);
        }
        return array;
    }

    /**
     * Object Literals
     * 
createObjectLiteral rewrites its argument as object * creation plus object property entries, so later compiler * stages don't need to know about object literals. */ Node createObjectLiteral(ObjArray elems) { int size = elems.size() / 2; Node object = new Node(Token.OBJECTLIT); Object[] properties; if (size == 0) { properties = ScriptRuntime.emptyArgs; } else { properties = new Object[size]; for (int i = 0; i != size; ++i) { properties[i] = elems.get(2 * i); Node value = (Node)elems.get(2 * i + 1); object.addChildToBack(value); } } object.putProp(Node.OBJECT_IDS_PROP, properties); return object; } /** * Regular expressions */ Node createRegExp(int regexpIndex) { Node n = new Node(Token.REGEXP); n.putIntProp(Node.REGEXP_PROP, regexpIndex); return n; } /** * If statement */ Node createIf(Node cond, Node ifTrue, Node ifFalse, int lineno) { int condStatus = isAlwaysDefinedBoolean(cond); if (condStatus == ALWAYS_TRUE_BOOLEAN) { return ifTrue; } else if (condStatus == ALWAYS_FALSE_BOOLEAN) { if (ifFalse != null) { return ifFalse; } // Replace if (false) xxx by empty block return new Node(Token.BLOCK, lineno); } Node result = new Node(Token.BLOCK, lineno); Node ifNotTarget = Node.newTarget(); Node.Jump IFNE = new Node.Jump(Token.IFNE, cond); IFNE.target = ifNotTarget; result.addChildToBack(IFNE); result.addChildrenToBack(ifTrue); if (ifFalse != null) { Node endTarget = Node.newTarget(); result.addChildToBack(makeJump(Token.GOTO, endTarget)); result.addChildToBack(ifNotTarget); result.addChildrenToBack(ifFalse); result.addChildToBack(endTarget); } else { result.addChildToBack(ifNotTarget); } return result; } Node createCondExpr(Node cond, Node ifTrue, Node ifFalse) { int condStatus = isAlwaysDefinedBoolean(cond); if (condStatus == ALWAYS_TRUE_BOOLEAN) { return ifTrue; } else if (condStatus == ALWAYS_FALSE_BOOLEAN) { return ifFalse; } return new Node(Token.HOOK, cond, ifTrue, ifFalse); } /** * Unary */ Node createUnary(int nodeType, Node child) { int childType = child.getType(); switch (nodeType) { case Token.DELPROP: { Node n; if (childType == Token.NAME) { // Transform Delete(Name "a") // to Delete(Bind("a"), String("a")) child.setType(Token.BINDNAME); Node left = child; Node right = Node.newString(child.getString()); n = new Node(nodeType, left, right); } else if (childType == Token.GETPROP || childType == Token.GETELEM) { Node left = child.getFirstChild(); Node right = child.getLastChild(); child.removeChild(left); child.removeChild(right); n = new Node(nodeType, left, right); } else if (childType == Token.GET_REF) { Node ref = child.getFirstChild(); child.removeChild(ref); n = new Node(Token.DEL_REF, ref); } else { n = new Node(Token.TRUE); } return n; } case Token.TYPEOF: if (childType == Token.NAME) { child.setType(Token.TYPEOFNAME); return child; } break; case Token.BITNOT: if (childType == Token.NUMBER) { int value = ScriptRuntime.toInt32(child.getDouble()); child.setDouble(~value); return child; } break; case Token.NEG: if (childType == Token.NUMBER) { child.setDouble(-child.getDouble()); return child; } break; case Token.NOT: { int status = isAlwaysDefinedBoolean(child); if (status != 0) { int type; if (status == ALWAYS_TRUE_BOOLEAN) { type = Token.FALSE; } else { type = Token.TRUE; } if (childType == Token.TRUE || childType == Token.FALSE) { child.setType(type); return child; } return new Node(type); } break; } } return new Node(nodeType, child); } Node createCallOrNew(int nodeType, Node child) { int type = Node.NON_SPECIALCALL; if (child.getType() == Token.NAME) { String name = child.getString(); if (name.equals("eval")) { type = Node.SPECIALCALL_EVAL; } else if (name.equals("With")) { type = Node.SPECIALCALL_WITH; } } else if (child.getType() == Token.GETPROP) { String name = child.getLastChild().getString(); if (name.equals("eval")) { type = Node.SPECIALCALL_EVAL; } } Node node = new Node(nodeType, child); if (type != Node.NON_SPECIALCALL) { // Calls to these functions require activation objects. setRequiresActivation(); node.putIntProp(Node.SPECIALCALL_PROP, type); } return node; } Node createIncDec(int nodeType, boolean post, Node child) { child = makeReference(child); if (child == null) { String msg; if (nodeType == Token.DEC) { msg = "msg.bad.decr"; } else { msg = "msg.bad.incr"; } parser.reportError(msg); return null; } int childType = child.getType(); switch (childType) { case Token.NAME: case Token.GETPROP: case Token.GETELEM: case Token.GET_REF: { Node n = new Node(nodeType, child); int incrDecrMask = 0; if (nodeType == Token.DEC) { incrDecrMask |= Node.DECR_FLAG; } if (post) { incrDecrMask |= Node.POST_FLAG; } n.putIntProp(Node.INCRDECR_PROP, incrDecrMask); return n; } } throw Kit.codeBug(); } Node createPropertyGet(Node target, String namespace, String name, int memberTypeFlags) { if (namespace == null && memberTypeFlags == 0) { if (target == null) { return createName(name); } checkActivationName(name, Token.GETPROP); if (ScriptRuntime.isSpecialProperty(name)) { Node ref = new Node(Token.REF_SPECIAL, target); ref.putProp(Node.NAME_PROP, name); return new Node(Token.GET_REF, ref); } return new Node(Token.GETPROP, target, createString(name)); } Node elem = createString(name); memberTypeFlags |= Node.PROPERTY_FLAG; return createMemberRefGet(target, namespace, elem, memberTypeFlags); } Node createElementGet(Node target, String namespace, Node elem, int memberTypeFlags) { // OPT: could optimize to createPropertyGet // iff elem is string that can not be number if (namespace == null && memberTypeFlags == 0) { // stand-alone [aaa] as primary expression is array literal // declaration and should not come here! if (target == null) throw Kit.codeBug(); return new Node(Token.GETELEM, target, elem); } return createMemberRefGet(target, namespace, elem, memberTypeFlags); } private Node createMemberRefGet(Node target, String namespace, Node elem, int memberTypeFlags) { Node nsNode = null; if (namespace != null) { // See 11.1.2 in ECMA 357 if (namespace.equals("*")) { nsNode = new Node(Token.NULL); } else { nsNode = createName(namespace); } } Node ref; if (target == null) { if (namespace == null) { ref = new Node(Token.REF_NAME, elem); } else { ref = new Node(Token.REF_NS_NAME, nsNode, elem); } } else { if (namespace == null) { ref = new Node(Token.REF_MEMBER, target, elem); } else { ref = new Node(Token.REF_NS_MEMBER, target, nsNode, elem); } } if (memberTypeFlags != 0) { ref.putIntProp(Node.MEMBER_TYPE_PROP, memberTypeFlags); } return new Node(Token.GET_REF, ref); } /** * Binary */ Node createBinary(int nodeType, Node left, Node right) { switch (nodeType) { case Token.ADD: // numerical addition and string concatenation if (left.type == Token.STRING) { String s2; if (right.type == Token.STRING) { s2 = right.getString(); } else if (right.type == Token.NUMBER) { s2 = ScriptRuntime.numberToString(right.getDouble(), 10); } else { break; } String s1 = left.getString(); left.setString(s1.concat(s2)); return left; } else if (left.type == Token.NUMBER) { if (right.type == Token.NUMBER) { left.setDouble(left.getDouble() + right.getDouble()); return left; } else if (right.type == Token.STRING) { String s1, s2; s1 = ScriptRuntime.numberToString(left.getDouble(), 10); s2 = right.getString(); right.setString(s1.concat(s2)); return right; } } // can't do anything if we don't know both types - since // 0 + object is supposed to call toString on the object and do // string concantenation rather than addition break; case Token.SUB: // numerical subtraction if (left.type == Token.NUMBER) { double ld = left.getDouble(); if (right.type == Token.NUMBER) { //both numbers left.setDouble(ld - right.getDouble()); return left; } else if (ld == 0.0) { // first 0: 0-x -> -x return new Node(Token.NEG, right); } } else if (right.type == Token.NUMBER) { if (right.getDouble() == 0.0) { //second 0: x - 0 -> +x // can not make simply x because x - 0 must be number return new Node(Token.POS, left); } } break; case Token.MUL: // numerical multiplication if (left.type == Token.NUMBER) { double ld = left.getDouble(); if (right.type == Token.NUMBER) { //both numbers left.setDouble(ld * right.getDouble()); return left; } else if (ld == 1.0) { // first 1: 1 * x -> +x return new Node(Token.POS, right); } } else if (right.type == Token.NUMBER) { if (right.getDouble() == 1.0) { //second 1: x * 1 -> +x // can not make simply x because x - 0 must be number return new Node(Token.POS, left); } } // can't do x*0: Infinity * 0 gives NaN, not 0 break; case Token.DIV: // number division if (right.type == Token.NUMBER) { double rd = right.getDouble(); if (left.type == Token.NUMBER) { // both constants -- just divide, trust Java to handle x/0 left.setDouble(left.getDouble() / rd); return left; } else if (rd == 1.0) { // second 1: x/1 -> +x // not simply x to force number convertion return new Node(Token.POS, left); } } break; case Token.AND: { // Since x && y gives x, not false, when Boolean(x) is false, // and y, not Boolean(y), when Boolean(x) is true, x && y // can only be simplified if x is defined. See bug 309957. int leftStatus = isAlwaysDefinedBoolean(left); if (leftStatus == ALWAYS_FALSE_BOOLEAN) { // if the first one is false, just return it return left; } else if (leftStatus == ALWAYS_TRUE_BOOLEAN) { // if first is true, set to second return right; } break; } case Token.OR: { // Since x || y gives x, not true, when Boolean(x) is true, // and y, not Boolean(y), when Boolean(x) is false, x || y // can only be simplified if x is defined. See bug 309957. int leftStatus = isAlwaysDefinedBoolean(left); if (leftStatus == ALWAYS_TRUE_BOOLEAN) { // if the first one is true, just return it return left; } else if (leftStatus == ALWAYS_FALSE_BOOLEAN) { // if first is false, set to second return right; } break; } } return new Node(nodeType, left, right); } private Node simpleAssignment(Node left, Node right) { int nodeType = left.getType(); switch (nodeType) { case Token.NAME: left.setType(Token.BINDNAME); return new Node(Token.SETNAME, left, right); case Token.GETPROP: case Token.GETELEM: { Node obj = left.getFirstChild(); Node id = left.getLastChild(); int type; if (nodeType == Token.GETPROP) { type = Token.SETPROP; } else { type = Token.SETELEM; } return new Node(type, obj, id, right); } case Token.GET_REF: { Node ref = left.getFirstChild(); checkMutableReference(ref); return new Node(Token.SET_REF, ref, right); } } throw Kit.codeBug(); } private void checkMutableReference(Node n) { int memberTypeFlags = n.getIntProp(Node.MEMBER_TYPE_PROP, 0); if ((memberTypeFlags & Node.DESCENDANTS_FLAG) != 0) { parser.reportError("msg.bad.assign.left"); } } Node createAssignment(int assignType, Node left, Node right) { left = makeReference(left); if (left == null) { parser.reportError("msg.bad.assign.left"); return right; } int assignOp; switch (assignType) { case Token.ASSIGN: return simpleAssignment(left, right); case Token.ASSIGN_BITOR: assignOp = Token.BITOR; break; case Token.ASSIGN_BITXOR: assignOp = Token.BITXOR; break; case Token.ASSIGN_BITAND: assignOp = Token.BITAND; break; case Token.ASSIGN_LSH: assignOp = Token.LSH; break; case Token.ASSIGN_RSH: assignOp = Token.RSH; break; case Token.ASSIGN_URSH: assignOp = Token.URSH; break; case Token.ASSIGN_ADD: assignOp = Token.ADD; break; case Token.ASSIGN_SUB: assignOp = Token.SUB; break; case Token.ASSIGN_MUL: assignOp = Token.MUL; break; case Token.ASSIGN_DIV: assignOp = Token.DIV; break; case Token.ASSIGN_MOD: assignOp = Token.MOD; break; default: throw Kit.codeBug(); } int nodeType = left.getType(); switch (nodeType) { case Token.NAME: { String s = left.getString(); Node opLeft = Node.newString(Token.NAME, s); Node op = new Node(assignOp, opLeft, right); Node lvalueLeft = Node.newString(Token.BINDNAME, s); return new Node(Token.SETNAME, lvalueLeft, op); } case Token.GETPROP: case Token.GETELEM: { Node obj = left.getFirstChild(); Node id = left.getLastChild(); int type = nodeType == Token.GETPROP ? Token.SETPROP_OP : Token.SETELEM_OP; Node opLeft = new Node(Token.USE_STACK); Node op = new Node(assignOp, opLeft, right); return new Node(type, obj, id, op); } case Token.GET_REF: { Node ref = left.getFirstChild(); checkMutableReference(ref); Node opLeft = new Node(Token.USE_STACK); Node op = new Node(assignOp, opLeft, right); return new Node(Token.SET_REF_OP, ref, op); } } throw Kit.codeBug(); } Node createUseLocal(Node localBlock) { if (Token.LOCAL_BLOCK != localBlock.getType()) throw Kit.codeBug(); Node result = new Node(Token.LOCAL_LOAD); result.putProp(Node.LOCAL_BLOCK_PROP, localBlock); return result; } private Node.Jump makeJump(int type, Node target) { Node.Jump n = new Node.Jump(type); n.target = target; return n; } private Node makeReference(Node node) { int type = node.getType(); switch (type) { case Token.NAME: case Token.GETPROP: case Token.GETELEM: case Token.GET_REF: return node; case Token.CALL: node.setType(Token.REF_CALL); return new Node(Token.GET_REF, node); } // Signal caller to report error return null; } // Check if Node always mean true or false in boolean context private static int isAlwaysDefinedBoolean(Node node) { switch (node.getType()) { case Token.FALSE: case Token.NULL: return ALWAYS_FALSE_BOOLEAN; case Token.TRUE: return ALWAYS_TRUE_BOOLEAN; case Token.NUMBER: { double num = node.getDouble(); if (num == num && num != 0.0) { return ALWAYS_TRUE_BOOLEAN; } else { return ALWAYS_FALSE_BOOLEAN; } } } return 0; } // Commented-out: no longer used // private static boolean hasSideEffects(Node exprTree) // { // switch (exprTree.getType()) { // case Token.INC: // case Token.DEC: // case Token.SETPROP: // case Token.SETELEM: // case Token.SETNAME: // case Token.CALL: // case Token.NEW: // return true; // default: // Node child = exprTree.getFirstChild(); // while (child != null) { // if (hasSideEffects(child)) // return true; // child = child.getNext(); // } // break; // } // return false; // } private void checkActivationName(String name, int token) { if (parser.insideFunction()) { boolean activation = false; if ("arguments".equals(name) || (parser.compilerEnv.activationNames != null && parser.compilerEnv.activationNames.containsKey(name))) { activation = true; } else if ("length".equals(name)) { if (token == Token.GETPROP && parser.compilerEnv.getLanguageVersion() == Context.VERSION_1_2) { // Use of "length" in 1.2 requires an activation object. activation = true; } } if (activation) { setRequiresActivation(); } } } private void setRequiresActivation() { if (parser.insideFunction()) { ((FunctionNode)parser.currentScriptOrFn).itsNeedsActivation = true; } } private Parser parser; private static final int LOOP_DO_WHILE = 0; private static final int LOOP_WHILE = 1; private static final int LOOP_FOR = 2; private static final int ALWAYS_TRUE_BOOLEAN = 1; private static final int ALWAYS_FALSE_BOOLEAN = -1; }




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