Mercurial > hg > graal-compiler
view graal/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/Fallback.java @ 18344:cc291e4c5564
made InvokeTarget and ForeignCallsProvider extend Remote
author | Doug Simon <doug.simon@oracle.com> |
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date | Wed, 12 Nov 2014 10:39:39 +0100 |
parents | 7b6a4ae58de4 |
children |
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/* * Copyright (c) 2012, 2014, 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 com.oracle.truffle.api.dsl; import java.lang.annotation.*; import com.oracle.truffle.api.nodes.*; /** * <p> * A method annotated with {@link Fallback} is treated as a {@link Specialization} that implicitly * links all the guards of all other declared {@link Specialization} annotated methods of the * operation in a negated form. As a consequence it cannot declare any other guards. The expected * signature of the method must match to the signature of a {@link Specialization} with the * additional limitation that only generically executable argument types are allowed. A generically * executable argument is a an argument hat can be executed from the child {@link Node} using an * execute method without {@link UnsupportedOperationException}. In many cases the generically * executable type is {@link Object}. An operation is limited to just one {@link Fallback} * specialization which is always ordered at the end of the specialization chain. * </p> * * <p> * A simple example showing the use of the {@link Fallback} annotation in a DSL operation: * </p> * * <pre> * @Specialization int doInt(int a) {..} * @Specialization int doDouble(double a) {..} * @Fallback int orElse(Object a) {..} * </pre> * * <p> * The previous example could be redeclared just using {@link Specialization} annotated methods as * follows: * </p> * * <pre> * @Specialization int doInt(int a) {..} * @Specialization int doDouble(double a) {..} * @Specialization(guard={"!isInt(a)", "!isDouble(a)"}) * int orElse(Object a) {..} * </pre> * * <p> * <b>Performance note:</b> For operations with a lot of {@link Specialization} annotated methods * the use of {@link Fallback} might generate a guard that is very big. Try to avoid the use of * {@link Fallback} for specializations that are significantly important for peak performance. * </p> * * @see Specialization * @see NodeChild */ @Retention(RetentionPolicy.CLASS) @Target({ElementType.METHOD}) public @interface Fallback { }