Mercurial > hg > openjdk > jigsaw > nashorn
view src/jdk/nashorn/internal/ir/TypeOverride.java @ 143:4be452026847
8010652: Eliminate non-child references in Block/FunctionNode, and make few node types immutable
Reviewed-by: jlaskey, lagergren
author | attila |
---|---|
date | Sat, 23 Mar 2013 00:58:39 +0100 |
parents | 5a1b0714df0e |
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; /** * A type override makes it possible to change the return type of a node, if we know * that the linker can provide it directly. For example, an identity node that is * in the scope, can very well look like an object to the compiler of the method it * is in, but if someone does (int)x, it make senses to ask for it directly * with an int getter instead of loading it as an object and explicitly converting it * by using JSType.toInt32. Especially in scenarios where the field is already stored * as a primitive, this will be much faster than the "object is all I see" scope * available in the method * @param <T> the type of the node implementing the interface */ public interface TypeOverride<T extends Node> { /** * Set the override type * * @param type the type * @return a node equivalent to this one except for the requested change. */ public T setType(final Type type); /** * Returns true if this node can have a callsite override, e.g. all scope ident nodes * which lead to dynamic getters can have it, local variable nodes (slots) can't. * Call nodes can have it unconditionally and so on * * @return true if it is possible to assign a type override to this node */ public boolean canHaveCallSiteType(); }