Mercurial > hg > truffle
annotate agent/src/share/classes/sun/jvm/hotspot/utilities/RobustOopDeterminator.java @ 113:ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold
author | coleenp |
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date | Sun, 13 Apr 2008 17:43:42 -0400 |
parents | a61af66fc99e |
children | d1605aabd0a1 |
rev | line source |
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0 | 1 /* |
2 * Copyright 2000 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 package sun.jvm.hotspot.utilities; | |
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 | |
33 /** This class determines to the best of its ability, and in a | |
34 reasonably robust fashion, whether a given pointer is an intact | |
35 oop or not. It does this by checking the integrity of the | |
36 metaclass hierarchy. This is only intended for use in the | |
37 debugging system. It may provide more resilience to unexpected VM | |
38 states than the ObjectHeap code. */ | |
39 | |
40 public class RobustOopDeterminator { | |
41 private static OopField klassField; | |
42 | |
43 static { | |
44 VM.registerVMInitializedObserver(new Observer() { | |
45 public void update(Observable o, Object data) { | |
46 initialize(VM.getVM().getTypeDataBase()); | |
47 } | |
48 }); | |
49 } | |
50 | |
51 private static void initialize(TypeDataBase db) { | |
52 Type type = db.lookupType("oopDesc"); | |
53 | |
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
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54 if (VM.getVM().isCompressedOopsEnabled()) { |
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
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55 klassField = type.getNarrowOopField("_metadata._compressed_klass"); |
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
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56 } else { |
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
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57 klassField = type.getOopField("_metadata._klass"); |
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6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
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58 } |
0 | 59 } |
60 | |
61 public static boolean oopLooksValid(OopHandle oop) { | |
62 if (oop == null) { | |
63 return false; | |
64 } | |
65 if (!VM.getVM().getUniverse().isIn(oop)) { | |
66 return false; | |
67 } | |
68 try { | |
69 for (int i = 0; i < 4; ++i) { | |
70 OopHandle next = klassField.getValue(oop); | |
71 if (next == null) { | |
72 return false; | |
73 } | |
74 if (next.equals(oop)) { | |
75 return true; | |
76 } | |
77 oop = next; | |
78 } | |
79 return false; | |
80 } | |
81 catch (AddressException e) { | |
82 return false; | |
83 } | |
84 } | |
85 } |