1 /*
2 * Copyright (c) 2000, 2020, 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.util.*;
28 import sun.jvm.hotspot.debugger.*;
29 import sun.jvm.hotspot.memory.*;
30 import sun.jvm.hotspot.runtime.*;
31 import sun.jvm.hotspot.types.*;
32 import sun.jvm.hotspot.utilities.Observable;
33 import sun.jvm.hotspot.utilities.Observer;
34
35 // Array is an abstract superclass for TypeArray and ObjArray
36
37 public class Array extends 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 Array(OopHandle handle, ObjectHeap heap) {
47 super(handle, heap);
48 }
49
50 private static void initialize(TypeDataBase db) throws WrongTypeException {
51 Type type = db.lookupType("arrayOopDesc");
52 typeSize = (int)type.getSize();
53 }
54
55 // Size of the arrayOopDesc
56 private static long headerSize=0;
57 private static long lengthOffsetInBytes=0;
58 private static long typeSize;
59
60 // Check whether an element of a typeArrayOop with the given type must be
61 // aligned 0 mod 8. The typeArrayOop itself must be aligned at least this
62 // strongly.
63 public static boolean elementTypeShouldBeAligned(BasicType type) {
64 if (VM.getVM().isLP64()) {
65 if (type == BasicType.T_OBJECT || type == BasicType.T_ARRAY) {
66 return !VM.getVM().isCompressedOopsEnabled();
67 }
68 }
69 return type == BasicType.T_DOUBLE || type == BasicType.T_LONG;
70 }
71
72 private static long headerSizeInBytes() {
73 if (headerSize != 0) {
74 return headerSize;
75 }
76 if (VM.getVM().isCompactObjectHeadersEnabled()) {
77 headerSize = lengthOffsetInBytes() + VM.getVM().getIntSize();
78 } else {
79 if (VM.getVM().isCompressedKlassPointersEnabled()) {
80 headerSize = typeSize;
81 } else {
82 headerSize = VM.getVM().alignUp(typeSize + VM.getVM().getIntSize(),
83 VM.getVM().getHeapWordSize());
84 }
85 }
86 return headerSize;
87 }
88
89 private static long headerSize(BasicType type) {
90 if (elementTypeShouldBeAligned(type)) {
91 return alignObjectSize(headerSizeInBytes())/VM.getVM().getHeapWordSize();
92 } else {
93 return headerSizeInBytes()/VM.getVM().getHeapWordSize();
94 }
95 }
96
97 private static long lengthOffsetInBytes() {
98 if (lengthOffsetInBytes != 0) {
99 return lengthOffsetInBytes;
100 }
101 if (VM.getVM().isCompactObjectHeadersEnabled()) {
102 lengthOffsetInBytes = Oop.getHeaderSize();
103 } else {
104 if (VM.getVM().isCompressedKlassPointersEnabled()) {
105 lengthOffsetInBytes = typeSize - VM.getVM().getIntSize();
106 } else {
107 lengthOffsetInBytes = typeSize;
108 }
109 }
110 return lengthOffsetInBytes;
111 }
112
113 // Accessors for declared fields
114 public long getLength() {
115 boolean isUnsigned = true;
116 return this.getHandle().getCIntegerAt(lengthOffsetInBytes(), VM.getVM().getIntSize(), isUnsigned);
117 }
118
119 public long getObjectSize() {
120 ArrayKlass klass = (ArrayKlass) getKlass();
121 // We have to fetch the length of the array, shift (multiply) it
122 // appropriately, up to wordSize, add the header, and align to
123 // object size.
124 long s = getLength() << klass.getLog2ElementSize();
125 s += klass.getArrayHeaderInBytes();
126 s = Oop.alignObjectSize(s);
127 return s;
128 }
129
130 public static long baseOffsetInBytes(BasicType type) {
131 if (VM.getVM().isCompactObjectHeadersEnabled()) {
132 long typeSizeInBytes = headerSizeInBytes();
133 if (elementTypeShouldBeAligned(type)) {
134 VM vm = VM.getVM();
135 return vm.alignUp(typeSizeInBytes, vm.getVM().getHeapWordSize());
136 } else {
137 return typeSizeInBytes;
138 }
139 } else {
140 return headerSize(type) * VM.getVM().getHeapWordSize();
141 }
142 }
143
144 public boolean isArray() { return true; }
145
146 public void iterateFields(OopVisitor visitor, boolean doVMFields) {
147 super.iterateFields(visitor, doVMFields);
148 }
149 }