Source code

001/*
002 * Copyright (c) 2010, 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.code;
024
025import java.util.*;
026
027import jdk.internal.jvmci.meta.*;
028
029/**
030 * An instance of this class represents an object whose allocation was removed by escape analysis.
031 * The information stored in the {@link VirtualObject} is used during deoptimization to recreate the
032 * object.
033 */
034public final class VirtualObject extends AbstractValue implements JavaValue {
035
036    private final ResolvedJavaType type;
037    private Value[] values;
038    private final int id;
039
040    /**
041     * Creates a new {@link VirtualObject} for the given type, with the given fields. If
042     * {@code type} is an instance class then {@code values} provides the values for the fields
043     * returned by {@link ResolvedJavaType#getInstanceFields(boolean) getInstanceFields(true)}. If
044     * {@code type} is an array then the length of the values array determines the reallocated array
045     * length.
046     *
047     * @param type the type of the object whose allocation was removed during compilation. This can
048     *            be either an instance of an array type.
049     * @param values an array containing all the values to be stored into the object when it is
050     *            recreated
051     * @param id a unique id that identifies the object within the debug information for one
052     *            position in the compiled code.
053     * @return a new {@link VirtualObject} instance.
054     */
055    public static VirtualObject get(ResolvedJavaType type, Value[] values, int id) {
056        return new VirtualObject(type, values, id);
057    }
058
059    private VirtualObject(ResolvedJavaType type, Value[] values, int id) {
060        super(LIRKind.reference(Kind.Object));
061        this.type = type;
062        this.values = values;
063        this.id = id;
064    }
065
066    private static StringBuilder appendValue(StringBuilder buf, Value value, Set<VirtualObject> visited) {
067        if (value instanceof VirtualObject) {
068            VirtualObject vo = (VirtualObject) value;
069            buf.append("vobject:").append(vo.type.toJavaName(false)).append(':').append(vo.id);
070            if (!visited.contains(vo)) {
071                visited.add(vo);
072                buf.append('{');
073                if (vo.values == null) {
074                    buf.append("<uninitialized>");
075                } else {
076                    if (vo.type.isArray()) {
077                        for (int i = 0; i < vo.values.length; i++) {
078                            if (i != 0) {
079                                buf.append(',');
080                            }
081                            buf.append(i).append('=');
082                            appendValue(buf, vo.values[i], visited);
083                        }
084                    } else {
085                        ResolvedJavaField[] fields = vo.type.getInstanceFields(true);
086                        assert fields.length == vo.values.length : vo.type + ", fields=" + Arrays.toString(fields) + ", values=" + Arrays.toString(vo.values);
087                        for (int i = 0; i < vo.values.length; i++) {
088                            if (i != 0) {
089                                buf.append(',');
090                            }
091                            buf.append(fields[i].getName()).append('=');
092                            appendValue(buf, vo.values[i], visited);
093                        }
094                    }
095                }
096                buf.append('}');
097            }
098        } else {
099            buf.append(value);
100        }
101        return buf;
102    }
103
104    @Override
105    public String toString() {
106        Set<VirtualObject> visited = Collections.newSetFromMap(new IdentityHashMap<VirtualObject, Boolean>());
107        return appendValue(new StringBuilder(), this, visited).toString();
108    }
109
110    /**
111     * Returns the type of the object whose allocation was removed during compilation. This can be
112     * either an instance of an array type.
113     */
114    public ResolvedJavaType getType() {
115        return type;
116    }
117
118    /**
119     * Returns an array containing all the values to be stored into the object when it is recreated.
120     */
121    public Value[] getValues() {
122        return values;
123    }
124
125    /**
126     * Returns the unique id that identifies the object within the debug information for one
127     * position in the compiled code.
128     */
129    public int getId() {
130        return id;
131    }
132
133    private static boolean checkValues(ResolvedJavaType type, Value[] values) {
134        if (values != null) {
135            if (!type.isArray()) {
136                ResolvedJavaField[] fields = type.getInstanceFields(true);
137                int fieldIndex = 0;
138                for (int i = 0; i < values.length; i++) {
139                    ResolvedJavaField field = fields[fieldIndex++];
140                    Kind valKind = values[i].getKind().getStackKind();
141                    if (field.getKind() == Kind.Object) {
142                        assert values[i].getLIRKind().isReference(0) : field + ": " + valKind + " != " + field.getKind();
143                    } else {
144                        if ((valKind == Kind.Double || valKind == Kind.Long) && field.getKind() == Kind.Int) {
145                            assert fields[fieldIndex].getKind() == Kind.Int;
146                            fieldIndex++;
147                        } else {
148                            assert valKind == field.getKind().getStackKind() : field + ": " + valKind + " != " + field.getKind();
149                        }
150                    }
151                }
152                assert fields.length == fieldIndex : type + ": fields=" + Arrays.toString(fields) + ", field values=" + Arrays.toString(values);
153            } else {
154                Kind componentKind = type.getComponentType().getKind().getStackKind();
155                if (componentKind == Kind.Object) {
156                    for (int i = 0; i < values.length; i++) {
157                        assert values[i].getLIRKind().isReference(0) : values[i].getKind() + " != " + componentKind;
158                    }
159                } else {
160                    for (int i = 0; i < values.length; i++) {
161                        assert values[i].getKind() == componentKind || componentKind.getBitCount() >= values[i].getKind().getBitCount() ||
162                                        (componentKind == Kind.Int && values[i].getKind().getBitCount() >= Kind.Int.getBitCount()) : values[i].getKind() + " != " + componentKind;
163                    }
164                }
165            }
166        }
167        return true;
168    }
169
170    /**
171     * Overwrites the current set of values with a new one.
172     *
173     * @param values an array containing all the values to be stored into the object when it is
174     *            recreated.
175     */
176    public void setValues(Value[] values) {
177        assert checkValues(type, values);
178        this.values = values;
179    }
180
181    @Override
182    public int hashCode() {
183        return getLIRKind().hashCode() + type.hashCode();
184    }
185
186    @Override
187    public boolean equals(Object o) {
188        if (o == this) {
189            return true;
190        }
191        if (o instanceof VirtualObject) {
192            VirtualObject l = (VirtualObject) o;
193            if (!l.type.equals(type) || l.values.length != values.length) {
194                return false;
195            }
196            for (int i = 0; i < values.length; i++) {
197                /*
198                 * Virtual objects can form cycles. Calling equals() could therefore lead to
199                 * infinite recursion.
200                 */
201                if (!same(values[i], l.values[i])) {
202                    return false;
203                }
204            }
205            return true;
206        }
207        return false;
208    }
209
210    private static boolean same(Object o1, Object o2) {
211        return o1 == o2;
212    }
213}