001/*
002 * Copyright (c) 2009, 2014, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package jdk.internal.jvmci.meta;
024
025/**
026 * Interface for values manipulated by the compiler. All values have a {@linkplain Kind kind} and
027 * are immutable.
028 */
029public interface Value extends KindProvider, TrustedInterface {
030
031    Value[] NO_VALUES = new Value[0];
032
033    AllocatableValue ILLEGAL = new IllegalValue();
034
035    public final class IllegalValue extends AllocatableValue {
036        private IllegalValue() {
037            super(LIRKind.Illegal);
038        }
039
040        @Override
041        public String toString() {
042            return "-";
043        }
044
045        @Override
046        public boolean equals(Object other) {
047            // Due to de-serialization this object may exist multiple times. So we compare classes
048            // instead of the individual objects. (This anonymous class has always the same meaning)
049            return other instanceof IllegalValue;
050        }
051    }
052
053    LIRKind getLIRKind();
054
055    /**
056     * Returns the platform specific kind used to store this value.
057     */
058    PlatformKind getPlatformKind();
059
060    /**
061     * Checks if this value is identical to {@code other}.
062     *
063     * Warning: Use with caution! Usually equivalence {@link #equals(Object)} is sufficient and
064     * should be used.
065     */
066    default boolean identityEquals(Value other) {
067        return this == other;
068    }
069}