author | coleenp |
Sun, 13 Apr 2008 17:43:42 -0400 | |
changeset 360 | 21d113ecbf6a |
parent 1 | 489c9b5090e2 |
child 670 | ddf3e9583f2f |
permissions | -rw-r--r-- |
1 | 1 |
/* |
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* Copyright 2000 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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* |
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*/ |
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package sun.jvm.hotspot.utilities; |
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import java.util.*; |
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import sun.jvm.hotspot.debugger.*; |
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import sun.jvm.hotspot.memory.*; |
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import sun.jvm.hotspot.runtime.*; |
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import sun.jvm.hotspot.types.*; |
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/** This class determines to the best of its ability, and in a |
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reasonably robust fashion, whether a given pointer is an intact |
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oop or not. It does this by checking the integrity of the |
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metaclass hierarchy. This is only intended for use in the |
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debugging system. It may provide more resilience to unexpected VM |
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states than the ObjectHeap code. */ |
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public class RobustOopDeterminator { |
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private static OopField klassField; |
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static { |
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VM.registerVMInitializedObserver(new Observer() { |
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public void update(Observable o, Object data) { |
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initialize(VM.getVM().getTypeDataBase()); |
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} |
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}); |
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} |
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private static void initialize(TypeDataBase db) { |
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Type type = db.lookupType("oopDesc"); |
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360
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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if (VM.getVM().isCompressedOopsEnabled()) { |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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klassField = type.getNarrowOopField("_metadata._compressed_klass"); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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} else { |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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klassField = type.getOopField("_metadata._klass"); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
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} |
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} |
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public static boolean oopLooksValid(OopHandle oop) { |
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if (oop == null) { |
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return false; |
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} |
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if (!VM.getVM().getUniverse().isIn(oop)) { |
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return false; |
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} |
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try { |
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for (int i = 0; i < 4; ++i) { |
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OopHandle next = klassField.getValue(oop); |
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if (next == null) { |
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return false; |
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} |
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if (next.equals(oop)) { |
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return true; |
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} |
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oop = next; |
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} |
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return false; |
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} |
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catch (AddressException e) { |
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return false; |
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} |
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} |
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} |