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 headerSize = 4;
51 } else {
52 headerSize = type.getSize();
53 klass = new MetadataField(type.getAddressField("_metadata._klass"), 0);
54 compressedKlass = new NarrowKlassField(type.getAddressField("_metadata._compressed_klass"), 0);
55 }
56 }
57
58 private OopHandle handle;
59 private ObjectHeap heap;
60
61 Oop(OopHandle handle, ObjectHeap heap) {
62 this.handle = handle;
63 this.heap = heap;
64 }
65
66 ObjectHeap getHeap() { return heap; }
67
68 /** Should not be used or needed by most clients outside this
69 package; is needed, however, by {@link
70 sun.jvm.hotspot.utilities.MarkBits}. */
71 public OopHandle getHandle() { return handle; }
72
73 private static long headerSize;
74 public static long getHeaderSize() { return headerSize; } // Header size in bytes.
75
76 private static CIntField mark;
77 private static MetadataField klass;
78 private static NarrowKlassField compressedKlass;
79
80 // Accessors for declared fields
81 public Mark getMark() { return new Mark(getHandle()); }
82
83 public Klass getKlass() {
84 if (VM.getVM().isCompactObjectHeadersEnabled()) {
85 assert(VM.getVM().isCompressedKlassPointersEnabled());
86 return getMark().getKlass();
87 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
88 return (Klass)compressedKlass.getValue(getHandle());
89 } else {
90 return (Klass)klass.getValue(getHandle());
91 }
92 }
93
94 public boolean isA(Klass k) {
95 return getKlass().isSubtypeOf(k);
96 }
97
98 // Returns the byte size of this object
99 public long getObjectSize() {
100 Klass k = getKlass();
101 // All other types should be overriding getObjectSize directly
102 return ((InstanceKlass)k).getObjectSize(this);
103 }
104
105 // Type test operations
106 public boolean isInstance() { return false; }
107 public boolean isInstanceRef() { return false; }
108 public boolean isArray() { return false; }
109 public boolean isObjArray() { return false; }
110 public boolean isTypeArray() { return false; }
111 public boolean isThread() { return false; }
112
113 // Align the object size.
114 public static long alignObjectSize(long size) {
115 return VM.getVM().alignUp(size, VM.getVM().getMinObjAlignmentInBytes());
116 }
117
118 // All vm's align longs, so pad out certain offsets.
119 public static long alignObjectOffset(long offset) {
120 return VM.getVM().alignUp(offset, VM.getVM().getBytesPerLong());
121 }
122
123 public boolean equals(Object obj) {
124 if (obj instanceof Oop other) {
125 return getHandle().equals(other.getHandle());
126 }
127 return false;
128 }
129
130 public int hashCode() { return getHandle().hashCode(); }
131
132 /** Identity hash in the target VM */
133 public long identityHash() {
134 if (VM.getVM().isCompactObjectHeadersEnabled()) {
135 System.exit(-23);
136 throw new InternalError("Not yet implemented");
137 }
138 Mark mark = getMark();
139 if (mark.isUnlocked() && (!mark.hasNoHash())) {
140 return (int) mark.hash();
141 } else if (mark.isMarked()) {
142 return (int) mark.hash();
143 } else {
144 return slowIdentityHash();
145 }
146 }
147
148 public long slowIdentityHash() {
149 return VM.getVM().getObjectSynchronizer().identityHashValueFor(this);
150 }
151
152 public void iterate(OopVisitor visitor, boolean doVMFields) {
153 visitor.setObj(this);
154 visitor.prologue();
155 iterateFields(visitor, doVMFields);
156 visitor.epilogue();
157 }
158
159 void iterateFields(OopVisitor visitor, boolean doVMFields) {
160 if (doVMFields) {
161 visitor.doCInt(mark, true);
162 if (!VM.getVM().isCompactObjectHeadersEnabled()) {
163 if (VM.getVM().isCompressedKlassPointersEnabled()) {
164 visitor.doMetadata(compressedKlass, true);
165 } else {
166 visitor.doMetadata(klass, true);
167 }
168 }
169 }
170 }
171
172 public void print() { printOn(System.out); }
173 public void printValue() { printValueOn(System.out); }
174 public void printRaw() { printRawOn(System.out); }
175
176 public static void printOopValueOn(Oop obj, PrintStream tty) {
177 if (obj == null) {
178 tty.print("null");
179 } else {
180 obj.printValueOn(tty);
181 tty.print(" @ " + VM.getVM().getUniverse().heap().oopAddressDescription(obj.getHandle()));
182 }
183 }
184
185 public static void printOopAddressOn(Oop obj, PrintStream tty) {
186 if (obj == null) {
187 tty.print("null");
188 } else {
189 tty.print(obj.getHandle().toString());
190 }
191 }
192
193 public void printOn(PrintStream tty) {
194 OopPrinter printer = new OopPrinter(tty);
195 iterate(printer, true);
196 }
197
198 public void printValueOn(PrintStream tty) {
199 try {
200 tty.print("Oop for " + getKlass().getName().asString());
201 } catch (java.lang.NullPointerException e) {
202 tty.print("Oop");
203 }
204 }
205
206 public void printRawOn(PrintStream tty) {
207 tty.print("Dumping raw memory for ");
208 printValueOn(tty);
209 tty.println();
210 long size = getObjectSize() * 4;
211 for (long i = 0; i < size; i += 4) {
212 long memVal = getHandle().getCIntegerAt(i, 4, true);
213 tty.println(Long.toHexString(memVal));
214 }
215 }
216
217 public boolean verify() { return true;}
218
219 public static Klass getKlassForOopHandle(OopHandle handle) {
220 if (handle == null) {
221 return null;
222 }
223 if (VM.getVM().isCompactObjectHeadersEnabled()) {
224 Mark mark = new Mark(handle);
225 return mark.getKlass();
226 } else if (VM.getVM().isCompressedKlassPointersEnabled()) {
227 return (Klass)Metadata.instantiateWrapperFor(handle.getCompKlassAddressAt(compressedKlass.getOffset()));
228 } else {
229 return (Klass)Metadata.instantiateWrapperFor(handle.getAddressAt(klass.getOffset()));
230 }
231 }
232 };