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 private static Klass getKlass(Mark mark) {
85 assert(VM.getVM().isCompactObjectHeadersEnabled());
86 if (mark.hasMonitor()) {
87 ObjectMonitor mon = mark.monitor();
88 mark = mon.header();
89 }
90 return mark.getKlass();
91 }
92
93 public Klass getKlass() {
94 if (VM.getVM().isCompactObjectHeadersEnabled()) {
95 assert(VM.getVM().isCompressedKlassPointersEnabled());
96 return getKlass(getMark());
97 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
98 return (Klass)compressedKlass.getValue(getHandle());
99 } else {
100 return (Klass)klass.getValue(getHandle());
101 }
102 }
103
104 public boolean isA(Klass k) {
105 return getKlass().isSubtypeOf(k);
106 }
107
108 // Returns the byte size of this object
109 public long getObjectSize() {
110 Klass k = getKlass();
111 // All other types should be overriding getObjectSize directly
112 return ((InstanceKlass)k).getObjectSize(this);
113 }
114
115 // Type test operations
116 public boolean isInstance() { return false; }
117 public boolean isInstanceRef() { return false; }
118 public boolean isArray() { return false; }
119 public boolean isObjArray() { return false; }
120 public boolean isTypeArray() { return false; }
121 public boolean isThread() { return false; }
122
123 // Align the object size.
124 public static long alignObjectSize(long size) {
125 return VM.getVM().alignUp(size, VM.getVM().getMinObjAlignmentInBytes());
126 }
127
128 // All vm's align longs, so pad out certain offsets.
129 public static long alignObjectOffset(long offset) {
130 return VM.getVM().alignUp(offset, VM.getVM().getBytesPerLong());
131 }
132
133 public boolean equals(Object obj) {
134 if (obj instanceof Oop other) {
135 return getHandle().equals(other.getHandle());
136 }
137 return false;
138 }
139
140 public int hashCode() { return getHandle().hashCode(); }
141
142 /** Identity hash in the target VM */
143 public long identityHash() {
144 Mark mark = getMark();
145 if (mark.isUnlocked() && (!mark.hasNoHash())) {
146 return (int) mark.hash();
147 } else if (mark.isMarked()) {
148 return (int) mark.hash();
149 } else {
150 return slowIdentityHash();
151 }
152 }
153
154 public long slowIdentityHash() {
155 return VM.getVM().getObjectSynchronizer().identityHashValueFor(this);
156 }
157
158 public void iterate(OopVisitor visitor, boolean doVMFields) {
159 visitor.setObj(this);
160 visitor.prologue();
161 iterateFields(visitor, doVMFields);
162 visitor.epilogue();
163 }
164
165 void iterateFields(OopVisitor visitor, boolean doVMFields) {
166 if (doVMFields) {
167 visitor.doCInt(mark, true);
168 if (!VM.getVM().isCompactObjectHeadersEnabled()) {
169 if (VM.getVM().isCompressedKlassPointersEnabled()) {
170 visitor.doMetadata(compressedKlass, true);
171 } else {
172 visitor.doMetadata(klass, true);
173 }
174 }
175 }
176 }
177
178 public void print() { printOn(System.out); }
179 public void printValue() { printValueOn(System.out); }
180 public void printRaw() { printRawOn(System.out); }
181
182 public static void printOopValueOn(Oop obj, PrintStream tty) {
183 if (obj == null) {
184 tty.print("null");
185 } else {
186 obj.printValueOn(tty);
187 tty.print(" @ " + VM.getVM().getUniverse().heap().oopAddressDescription(obj.getHandle()));
188 }
189 }
190
191 public static void printOopAddressOn(Oop obj, PrintStream tty) {
192 if (obj == null) {
193 tty.print("null");
194 } else {
195 tty.print(obj.getHandle().toString());
196 }
197 }
198
199 public void printOn(PrintStream tty) {
200 OopPrinter printer = new OopPrinter(tty);
201 iterate(printer, true);
202 }
203
204 public void printValueOn(PrintStream tty) {
205 try {
206 tty.print("Oop for " + getKlass().getName().asString());
207 } catch (java.lang.NullPointerException e) {
208 tty.print("Oop");
209 }
210 }
211
212 public void printRawOn(PrintStream tty) {
213 tty.print("Dumping raw memory for ");
214 printValueOn(tty);
215 tty.println();
216 long size = getObjectSize() * 4;
217 for (long i = 0; i < size; i += 4) {
218 long memVal = getHandle().getCIntegerAt(i, 4, true);
219 tty.println(Long.toHexString(memVal));
220 }
221 }
222
223 public boolean verify() { return true;}
224
225 public static Klass getKlassForOopHandle(OopHandle handle) {
226 if (handle == null) {
227 return null;
228 }
229 if (VM.getVM().isCompactObjectHeadersEnabled()) {
230 Mark mark = new Mark(handle);
231 return getKlass(mark);
232 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
233 return (Klass)Metadata.instantiateWrapperFor(handle.getCompKlassAddressAt(compressedKlass.getOffset()));
234 } else {
235 return (Klass)Metadata.instantiateWrapperFor(handle.getAddressAt(klass.getOffset()));
236 }
237 }
238 };