1 /*
2 * Copyright (c) 2010, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package jdk.vm.ci.code;
24
25 import java.util.Arrays;
26 import java.util.Collections;
27 import java.util.IdentityHashMap;
28 import java.util.Set;
29
30 import jdk.vm.ci.meta.JavaKind;
31 import jdk.vm.ci.meta.JavaValue;
32 import jdk.vm.ci.meta.ResolvedJavaField;
33 import jdk.vm.ci.meta.ResolvedJavaType;
34
35 /**
36 * An instance of this class represents an object whose allocation was removed by escape analysis.
37 * The information stored in the {@link VirtualObject} is used during deoptimization to recreate the
38 * object.
39 */
40 public final class VirtualObject implements JavaValue {
41
42 private final ResolvedJavaType type;
43 private JavaValue[] values;
44 private JavaKind[] slotKinds;
45 private final int id;
46
47 /**
48 * Creates a new {@link VirtualObject} for the given type, with the given fields. If
49 * {@code type} is an instance class then {@code values} provides the values for the fields
50 * returned by {@link ResolvedJavaType#getInstanceFields(boolean) getInstanceFields(true)}. If
51 * {@code type} is an array then the length of the values array determines the reallocated array
52 * length.
53 *
54 * @param type the type of the object whose allocation was removed during compilation. This can
55 * be either an instance of an array type.
56 * @param id a unique id that identifies the object within the debug information for one
57 * position in the compiled code.
58 * @return a new {@link VirtualObject} instance.
59 */
60 public static VirtualObject get(ResolvedJavaType type, int id) {
61 return new VirtualObject(type, id);
62 }
63
64 private VirtualObject(ResolvedJavaType type, int id) {
65 this.type = type;
66 this.id = id;
67 }
68
69 private static StringBuilder appendValue(StringBuilder buf, JavaValue value, Set<VirtualObject> visited) {
70 if (value instanceof VirtualObject) {
71 VirtualObject vo = (VirtualObject) value;
72 buf.append("vobject:").append(vo.type.toJavaName(false)).append(':').append(vo.id);
73 if (!visited.contains(vo)) {
74 visited.add(vo);
75 buf.append('{');
76 if (vo.values == null) {
77 buf.append("<uninitialized>");
78 } else {
79 if (vo.type.isArray()) {
80 for (int i = 0; i < vo.values.length; i++) {
81 if (i != 0) {
82 buf.append(',');
83 }
84 buf.append(i).append('=');
85 appendValue(buf, vo.values[i], visited);
86 }
87 } else {
88 ResolvedJavaField[] fields = vo.type.getInstanceFields(true);
89 assert fields.length == vo.values.length : vo.type + ", fields=" + Arrays.toString(fields) + ", values=" + Arrays.toString(vo.values);
90 for (int i = 0; i < vo.values.length; i++) {
91 if (i != 0) {
92 buf.append(',');
93 }
94 buf.append(fields[i].getName()).append('=');
95 appendValue(buf, vo.values[i], visited);
96 }
97 }
98 }
99 buf.append('}');
100 }
101 } else {
102 buf.append(value);
103 }
104 return buf;
105 }
106
107 @Override
108 public String toString() {
109 Set<VirtualObject> visited = Collections.newSetFromMap(new IdentityHashMap<VirtualObject, Boolean>());
110 return appendValue(new StringBuilder(), this, visited).toString();
111 }
112
113 /**
114 * Returns the type of the object whose allocation was removed during compilation. This can be
115 * either an instance of an array type.
116 */
117 public ResolvedJavaType getType() {
118 return type;
119 }
120
121 /**
122 * Returns an array containing all the values to be stored into the object when it is recreated.
123 */
124 public JavaValue[] getValues() {
125 return values;
126 }
127
128 /**
129 * Returns an array containing the Java kind of all values in the object.
130 */
131 public JavaKind[] getSlotKinds() {
132 return slotKinds;
133 }
134
135 /**
136 * Returns the unique id that identifies the object within the debug information for one
137 * position in the compiled code.
138 */
139 public int getId() {
140 return id;
141 }
142
143 /**
144 * Overwrites the current set of values with a new one.
145 *
146 * @param values an array containing all the values to be stored into the object when it is
147 * recreated.
148 * @param slotKinds an array containing the Java kinds of the values.
149 */
150 public void setValues(JavaValue[] values, JavaKind[] slotKinds) {
151 this.values = values;
152 this.slotKinds = slotKinds;
153 }
154
155 @Override
156 public int hashCode() {
157 return 42 + type.hashCode();
158 }
159
160 @Override
161 public boolean equals(Object o) {
162 if (o == this) {
163 return true;
164 }
165 if (o instanceof VirtualObject) {
166 VirtualObject l = (VirtualObject) o;
167 if (!l.type.equals(type) || l.values.length != values.length) {
168 return false;
169 }
170 for (int i = 0; i < values.length; i++) {
171 /*
172 * Virtual objects can form cycles. Calling equals() could therefore lead to
173 * infinite recursion.
174 */
175 if (!same(values[i], l.values[i])) {
176 return false;
177 }
178 }
179 return true;
180 }
181 return false;
182 }
183
184 private static boolean same(Object o1, Object o2) {
185 return o1 == o2;
186 }
187 }