Mercurial > hg > openjdk > lambda > nashorn
view src/jdk/nashorn/internal/ir/Expression.java @ 666:7985ec3782b5
8027042: Evaluation order for binary operators can be improved
Reviewed-by: lagergren, jlaskey, attila
author | hannesw |
---|---|
date | Fri, 25 Oct 2013 10:20:49 +0200 |
parents | 2c007a8bb0e7 |
children |
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/* * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package jdk.nashorn.internal.ir; import jdk.nashorn.internal.codegen.types.Type; /** * Common superclass for all expression nodes. Expression nodes can have * an associated symbol as well as a type. * */ public abstract class Expression extends Node { private Symbol symbol; Expression(long token, int start, int finish) { super(token, start, finish); } Expression(long token, int finish) { super(token, finish); } Expression(Expression expr) { super(expr); this.symbol = expr.symbol; } /** * Return the Symbol the compiler has assigned to this Node. The symbol * is the place where it's expression value is stored after evaluation * * @return the symbol */ public Symbol getSymbol() { return symbol; } /** * Assign a symbol to this node. See {@link Expression#getSymbol()} for explanation * of what a symbol is * * @param lc lexical context * @param symbol the symbol * @return new node */ public Expression setSymbol(final LexicalContext lc, final Symbol symbol) { if (this.symbol == symbol) { return this; } final Expression newExpr = (Expression)clone(); newExpr.symbol = symbol; return newExpr; } /** * Check if the expression has a type. The default behavior is to go into the symbol * and check the symbol type, but there may be overrides, for example in * getters that require a different type than the internal representation * * @return true if a type exists */ public boolean hasType() { return getSymbol() != null; } /** * Returns the type of the expression. Typically this is the symbol type. No types * are stored in the expression itself, unless it implements TypeOverride. * * @return the type of the node. */ public Type getType() { assert hasType() : this + " has no type"; return symbol.getSymbolType(); } /** * Returns {@code true} if this expression depends exclusively on state that is constant * or local to the currently running function and thus inaccessible to other functions. * This implies that a local expression must not call any other functions (neither directly * nor implicitly through a getter, setter, or object-to-primitive type conversion). * * @return true if this expression does not depend on state shared with other functions. */ public boolean isLocal() { return false; } }