Mercurial > hg > truffle
comparison agent/src/share/classes/sun/jvm/hotspot/utilities/ReversePtrs.java @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 |
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-1:000000000000 | 0:a61af66fc99e |
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1 /* | |
2 * Copyright 2002-2006 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.oops.*; | |
29 | |
30 /** ReversePtrs hashtable. */ | |
31 | |
32 public class ReversePtrs { | |
33 private HashMap rp; | |
34 | |
35 public ReversePtrs() { | |
36 rp = new HashMap(); | |
37 } | |
38 | |
39 public void put(LivenessPathElement from, Oop to) { | |
40 if (to == null) return; | |
41 ArrayList al = (ArrayList) rp.get((Object) to); | |
42 if (al == null) al = new ArrayList(); | |
43 // Inserting at the beginning is a hack to change the reported | |
44 // paths from LivenessAnalysis to look more like they used to; | |
45 // otherwise paths through the Finalizer queue to popular objects | |
46 // seem to be preferred | |
47 al.add(0, (Object) from); | |
48 rp.put((Object) to, (Object) al); | |
49 } | |
50 | |
51 /** Returns an ArrayList of the incoming references to this Oop if | |
52 it is alive, and null if it is dead according to the | |
53 ReversePtrsAnalysis. Currently not all roots are scanned so this | |
54 result is frequently inaccurate for JVM-internal objects, but is | |
55 usually correct for Java-level objects. */ | |
56 public ArrayList/*<LivenessPathElement>*/ get(Oop obj) { | |
57 return (ArrayList) rp.get((Object)obj); | |
58 } | |
59 } |