1 /*
  2  * Copyright (c) 2001, 2020, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 package sun.jvm.hotspot.runtime;
 26 
 27 import java.util.*;
 28 
 29 import sun.jvm.hotspot.debugger.*;
 30 import sun.jvm.hotspot.oops.*;
 31 import sun.jvm.hotspot.types.*;
 32 import sun.jvm.hotspot.utilities.Observable;
 33 import sun.jvm.hotspot.utilities.Observer;
 34 
 35 public class ObjectMonitor extends VMObject {
 36   static {
 37     VM.registerVMInitializedObserver(new Observer() {
 38         public void update(Observable o, Object data) {
 39           initialize(VM.getVM().getTypeDataBase());
 40         }
 41       });
 42   }
 43 
 44   private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
 45     heap = VM.getVM().getObjectHeap();
 46     Type type  = db.lookupType("ObjectMonitor");
 47     sun.jvm.hotspot.types.Field f = type.getField("_header");
 48     headerFieldOffset = f.getOffset();
 49     f = type.getField("_object");
 50     objectFieldOffset = f.getOffset();
 51     f = type.getField("_owner");
 52     ownerFieldOffset = f.getOffset();
 53     f = type.getField("_next_om");
 54     nextOMFieldOffset = f.getOffset();
 55     contentionsField  = type.getJIntField("_contentions");
 56     waitersField = type.getJIntField("_waiters");
 57     recursionsField = type.getCIntegerField("_recursions");


 58   }
 59 
 60   public ObjectMonitor(Address addr) {
 61     super(addr);
 62   }
 63 
 64   public Mark header() {
 65     return new Mark(addr.addOffsetTo(headerFieldOffset));
 66   }
 67 
 68   // FIXME
 69   //  void      set_header(markWord hdr);
 70 
 71   // FIXME: must implement and delegate to platform-dependent implementation
 72   //  public boolean isBusy();
 73   public boolean isEntered(sun.jvm.hotspot.runtime.Thread current) {
 74     Address o = owner();
 75     if (current.threadObjectAddress().equals(o) ||
 76         current.isLockOwned(o)) {
 77       return true;
 78     }
 79     return false;
 80   }
 81 




 82   public Address owner() { return addr.getAddressAt(ownerFieldOffset); }
 83   // FIXME
 84   //  void      set_owner(void* owner);
 85 
 86   public int    waiters() { return waitersField.getValue(addr); }
 87 
 88   public Address nextOM() { return addr.getAddressAt(nextOMFieldOffset); }
 89   // FIXME
 90   //  void      set_queue(void* owner);
 91 
 92   public long recursions() { return recursionsField.getValue(addr); }
 93 
 94   public OopHandle object() {
 95     Address objAddr = addr.getAddressAt(objectFieldOffset);
 96     if (objAddr == null) {
 97       return null;
 98     }
 99     return objAddr.getOopHandleAt(0);
100   }
101 
102   public int contentions() {
103       return contentionsField.getValue(addr);
104   }
105 
106   // The following four either aren't expressed as typed fields in
107   // vmStructs.cpp because they aren't strongly typed in the VM, or
108   // would confuse the SA's type system.
109   private static ObjectHeap    heap;
110   private static long          headerFieldOffset;
111   private static long          objectFieldOffset;
112   private static long          ownerFieldOffset;
113   private static long          nextOMFieldOffset;
114   private static JIntField     contentionsField;
115   private static JIntField     waitersField;
116   private static CIntegerField recursionsField;


117   // FIXME: expose platform-dependent stuff
118 }
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