/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.jvm.hotspot.oops;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.memory.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.types.Type;
import sun.jvm.hotspot.types.TypeDataBase;
import sun.jvm.hotspot.utilities.*;
import sun.jvm.hotspot.jdi.JVMTIThreadState;
/** A utility class encapsulating useful oop operations */
// initialize fields for java.lang.Class
public class java_lang_Class {
// java.lang.Class fields
static OopField klassField;
static IntField oopSizeField;
static {
VM.registerVMInitializedObserver(new Observer() {
public void update(Observable o, Object data) {
initialize(VM.getVM().getTypeDataBase());
}
});
}
private static synchronized void initialize(TypeDataBase db) {
// klass and oop_size are HotSpot magic fields and hence we can't
// find them from InstanceKlass for java.lang.Class.
Type jlc = db.lookupType("java_lang_Class");
int klassOffset = (int) jlc.getCIntegerField("_klass_offset").getValue();
if (VM.getVM().isCompressedOopsEnabled()) {
klassField = new NarrowOopField(new NamedFieldIdentifier("klass"), klassOffset, true);
} else {
klassField = new OopField(new NamedFieldIdentifier("klass"), klassOffset, true);
}
int oopSizeOffset = (int) jlc.getCIntegerField("_oop_size_offset").getValue();
oopSizeField = new IntField(new NamedFieldIdentifier("oop_size"), oopSizeOffset, true);
}
/** get klassOop field at offset hc_klass_offset from a java.lang.Class object */
public static Klass asKlass(Oop aClass) {
return (Klass) java_lang_Class.klassField.getValue(aClass);
}
/** get oop_size field at offset oop_size_offset from a java.lang.Class object */
public static long getOopSize(Oop aClass) {
return java_lang_Class.oopSizeField.getValue(aClass);
}
}