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 * Copyright (c) 2000, 2020, 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.io.*;
import java.util.*;
import sun.jvm.hotspot.utilities.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

// Oop represents the superclass for all types of
// objects in the HotSpot object heap.

public class Oop {
  static {
    VM.registerVMInitializedObserver(new Observer() {
        public void update(Observable o, Object data) {
          initialize(VM.getVM().getTypeDataBase());
        }
      });
  }

  private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
    Type type  = db.lookupType("oopDesc");
    mark       = new CIntField(type.getCIntegerField("_mark"), 0);
    klass      = new MetadataField(type.getAddressField("_metadata._klass"), 0);
    compressedKlass  = new NarrowKlassField(type.getAddressField("_metadata._compressed_klass"), 0);
    headerSize = type.getSize();
  }

  private OopHandle  handle;
  private ObjectHeap heap;

  Oop(OopHandle handle, ObjectHeap heap) {
    this.handle = handle;
    this.heap   = heap;
  }

  ObjectHeap getHeap()   { return heap; }

  
Should not be used or needed by most clients outside this package; is needed, however, by MarkBits.
/** Should not be used or needed by most clients outside this package; is needed, however, by {@link sun.jvm.hotspot.utilities.MarkBits}. */
public OopHandle getHandle() { return handle; } private static long headerSize; public static long getHeaderSize() { return headerSize; } // Header size in bytes. private static CIntField mark; private static MetadataField klass; private static NarrowKlassField compressedKlass; // Accessors for declared fields public Mark getMark() { return new Mark(getHandle()); } public Klass getKlass() { if (VM.getVM().isCompressedKlassPointersEnabled()) { return (Klass)compressedKlass.getValue(getHandle()); } else { return (Klass)klass.getValue(getHandle()); } } public boolean isA(Klass k) { return getKlass().isSubtypeOf(k); } // Returns the byte size of this object public long getObjectSize() { Klass k = getKlass(); // All other types should be overriding getObjectSize directly return ((InstanceKlass)k).getObjectSize(this); } // Type test operations public boolean isInstance() { return false; } public boolean isInstanceRef() { return false; } public boolean isArray() { return false; } public boolean isObjArray() { return false; } public boolean isTypeArray() { return false; } public boolean isThread() { return false; } // Align the object size. public static long alignObjectSize(long size) { return VM.getVM().alignUp(size, VM.getVM().getMinObjAlignmentInBytes()); } // All vm's align longs, so pad out certain offsets. public static long alignObjectOffset(long offset) { return VM.getVM().alignUp(offset, VM.getVM().getBytesPerLong()); } public boolean equals(Object obj) { if (obj != null && (obj instanceof Oop)) { return getHandle().equals(((Oop) obj).getHandle()); } return false; } public int hashCode() { return getHandle().hashCode(); }
Identity hash in the target VM
/** Identity hash in the target VM */
public long identityHash() { Mark mark = getMark(); if (mark.isUnlocked() && (!mark.hasNoHash())) { return (int) mark.hash(); } else if (mark.isMarked()) { return (int) mark.hash(); } else { return slowIdentityHash(); } } public long slowIdentityHash() { return VM.getVM().getObjectSynchronizer().identityHashValueFor(this); } public void iterate(OopVisitor visitor, boolean doVMFields) { visitor.setObj(this); visitor.prologue(); iterateFields(visitor, doVMFields); visitor.epilogue(); } void iterateFields(OopVisitor visitor, boolean doVMFields) { if (doVMFields) { visitor.doCInt(mark, true); if (VM.getVM().isCompressedKlassPointersEnabled()) { visitor.doMetadata(compressedKlass, true); } else { visitor.doMetadata(klass, true); } } } public void print() { printOn(System.out); } public void printValue() { printValueOn(System.out); } public void printRaw() { printRawOn(System.out); } public static void printOopValueOn(Oop obj, PrintStream tty) { if (obj == null) { tty.print("null"); } else { obj.printValueOn(tty); tty.print(" @ " + VM.getVM().getUniverse().heap().oopAddressDescription(obj.getHandle())); } } public static void printOopAddressOn(Oop obj, PrintStream tty) { if (obj == null) { tty.print("null"); } else { tty.print(obj.getHandle().toString()); } } public void printOn(PrintStream tty) { OopPrinter printer = new OopPrinter(tty); iterate(printer, true); } public void printValueOn(PrintStream tty) { try { tty.print("Oop for " + getKlass().getName().asString()); } catch (java.lang.NullPointerException e) { tty.print("Oop"); } } public void printRawOn(PrintStream tty) { tty.print("Dumping raw memory for "); printValueOn(tty); tty.println(); long size = getObjectSize() * 4; for (long i = 0; i < size; i += 4) { long memVal = getHandle().getCIntegerAt(i, 4, true); tty.println(Long.toHexString(memVal)); } } public boolean verify() { return true;} public static Klass getKlassForOopHandle(OopHandle handle) { if (handle == null) { return null; } if (VM.getVM().isCompressedKlassPointersEnabled()) { return (Klass)Metadata.instantiateWrapperFor(handle.getCompKlassAddressAt(compressedKlass.getOffset())); } else { return (Klass)Metadata.instantiateWrapperFor(handle.getAddressAt(klass.getOffset())); } } };