1 /*
2 * Copyright (c) 2000, 2022, 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 */
24
25 package sun.jvm.hotspot.oops;
26
27 import java.io.*;
28 import sun.jvm.hotspot.debugger.*;
29 import sun.jvm.hotspot.runtime.*;
30 import sun.jvm.hotspot.types.*;
31 import sun.jvm.hotspot.utilities.Observable;
32 import sun.jvm.hotspot.utilities.Observer;
33
34 // Oop represents the superclass for all types of
35 // objects in the HotSpot object heap.
36
37 public class Oop {
38 static {
39 VM.registerVMInitializedObserver(new Observer() {
40 public void update(Observable o, Object data) {
41 initialize(VM.getVM().getTypeDataBase());
42 }
43 });
44 }
45
46 private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
47 Type type = db.lookupType("oopDesc");
48 mark = new CIntField(type.getCIntegerField("_mark"), 0);
49 if (VM.getVM().isCompactObjectHeadersEnabled()) {
50 Type markType = db.lookupType("markWord");
51 headerSize = markType.getSize();
52 } else {
53 headerSize = type.getSize();
54 klass = new MetadataField(type.getAddressField("_metadata._klass"), 0);
55 compressedKlass = new NarrowKlassField(type.getAddressField("_metadata._compressed_klass"), 0);
56 }
57 }
58
59 private OopHandle handle;
60 private ObjectHeap heap;
61
62 Oop(OopHandle handle, ObjectHeap heap) {
63 this.handle = handle;
64 this.heap = heap;
65 }
66
67 ObjectHeap getHeap() { return heap; }
68
69 /** Should not be used or needed by most clients outside this
70 package; is needed, however, by {@link
71 sun.jvm.hotspot.utilities.MarkBits}. */
72 public OopHandle getHandle() { return handle; }
73
74 private static long headerSize;
75 public static long getHeaderSize() { return headerSize; } // Header size in bytes.
76
77 private static CIntField mark;
78 private static MetadataField klass;
79 private static NarrowKlassField compressedKlass;
80
81 // Accessors for declared fields
82 public Mark getMark() { return new Mark(getHandle()); }
83
84 public Klass getKlass() {
85 if (VM.getVM().isCompactObjectHeadersEnabled()) {
86 assert(VM.getVM().isCompressedKlassPointersEnabled());
87 return getMark().getKlass();
88 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
89 return (Klass)compressedKlass.getValue(getHandle());
90 } else {
91 return (Klass)klass.getValue(getHandle());
92 }
93 }
94
95 public boolean isA(Klass k) {
96 return getKlass().isSubtypeOf(k);
97 }
98
99 // Returns the byte size of this object
100 public long getObjectSize() {
101 Klass k = getKlass();
102 // All other types should be overriding getObjectSize directly
103 return ((InstanceKlass)k).getObjectSize(this);
104 }
105
106 // Type test operations
107 public boolean isInstance() { return false; }
108 public boolean isInstanceRef() { return false; }
109 public boolean isArray() { return false; }
110 public boolean isObjArray() { return false; }
111 public boolean isTypeArray() { return false; }
112 public boolean isThread() { return false; }
113
114 // Align the object size.
115 public static long alignObjectSize(long size) {
116 return VM.getVM().alignUp(size, VM.getVM().getMinObjAlignmentInBytes());
117 }
118
119 // All vm's align longs, so pad out certain offsets.
120 public static long alignObjectOffset(long offset) {
121 return VM.getVM().alignUp(offset, VM.getVM().getBytesPerLong());
122 }
123
124 public boolean equals(Object obj) {
125 if (obj instanceof Oop other) {
126 return getHandle().equals(other.getHandle());
127 }
128 return false;
129 }
130
131 public int hashCode() { return getHandle().hashCode(); }
132
133 /** Identity hash in the target VM */
134 public long identityHash() {
135 Mark mark = getMark();
136 if (mark.isUnlocked() && (!mark.hasNoHash())) {
137 return (int) mark.hash();
138 } else if (mark.isMarked()) {
139 return (int) mark.hash();
140 } else {
141 return slowIdentityHash();
142 }
143 }
144
145 public long slowIdentityHash() {
146 return VM.getVM().getObjectSynchronizer().identityHashValueFor(this);
147 }
148
149 public void iterate(OopVisitor visitor, boolean doVMFields) {
150 visitor.setObj(this);
151 visitor.prologue();
152 iterateFields(visitor, doVMFields);
153 visitor.epilogue();
154 }
155
156 void iterateFields(OopVisitor visitor, boolean doVMFields) {
157 if (doVMFields) {
158 visitor.doCInt(mark, true);
159 if (!VM.getVM().isCompactObjectHeadersEnabled()) {
160 if (VM.getVM().isCompressedKlassPointersEnabled()) {
161 visitor.doMetadata(compressedKlass, true);
162 } else {
163 visitor.doMetadata(klass, true);
164 }
165 }
166 }
167 }
168
169 public void print() { printOn(System.out); }
170 public void printValue() { printValueOn(System.out); }
171 public void printRaw() { printRawOn(System.out); }
172
173 public static void printOopValueOn(Oop obj, PrintStream tty) {
174 if (obj == null) {
175 tty.print("null");
176 } else {
177 obj.printValueOn(tty);
178 tty.print(" @ " + VM.getVM().getUniverse().heap().oopAddressDescription(obj.getHandle()));
179 }
180 }
181
182 public static void printOopAddressOn(Oop obj, PrintStream tty) {
183 if (obj == null) {
184 tty.print("null");
185 } else {
186 tty.print(obj.getHandle().toString());
187 }
188 }
189
190 public void printOn(PrintStream tty) {
191 OopPrinter printer = new OopPrinter(tty);
192 iterate(printer, true);
193 }
194
195 public void printValueOn(PrintStream tty) {
196 try {
197 tty.print("Oop for " + getKlass().getName().asString());
198 } catch (java.lang.NullPointerException e) {
199 tty.print("Oop");
200 }
201 }
202
203 public void printRawOn(PrintStream tty) {
204 tty.print("Dumping raw memory for ");
205 printValueOn(tty);
206 tty.println();
207 long size = getObjectSize() * 4;
208 for (long i = 0; i < size; i += 4) {
209 long memVal = getHandle().getCIntegerAt(i, 4, true);
210 tty.println(Long.toHexString(memVal));
211 }
212 }
213
214 public boolean verify() { return true;}
215
216 public static Klass getKlassForOopHandle(OopHandle handle) {
217 if (handle == null) {
218 return null;
219 }
220 if (VM.getVM().isCompactObjectHeadersEnabled()) {
221 Mark mark = new Mark(handle);
222 return mark.getKlass();
223 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
224 return (Klass)Metadata.instantiateWrapperFor(handle.getCompKlassAddressAt(compressedKlass.getOffset()));
225 } else {
226 return (Klass)Metadata.instantiateWrapperFor(handle.getAddressAt(klass.getOffset()));
227 }
228 }
229 };