1 /*
   2  * Copyright (c) 2001, 2014, 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 
  33 public class ObjectMonitor extends VMObject {
  34   static {
  35     VM.registerVMInitializedObserver(new Observer() {
  36         public void update(Observable o, Object data) {
  37           initialize(VM.getVM().getTypeDataBase());
  38         }
  39       });
  40   }
  41 
  42   private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
  43     heap = VM.getVM().getObjectHeap();
  44     Type type  = db.lookupType("ObjectMonitor");
  45     sun.jvm.hotspot.types.Field f = type.getField("_header");
  46     headerFieldOffset = f.getOffset();
  47     f = type.getField("_object");
  48     objectFieldOffset = f.getOffset();
  49     f = type.getField("_owner");
  50     ownerFieldOffset = f.getOffset();
  51     f = type.getField("FreeNext");
  52     FreeNextFieldOffset = f.getOffset();
  53     countField  = type.getJIntField("_count");
  54     waitersField = type.getJIntField("_waiters");
  55     recursionsField = type.getCIntegerField("_recursions");
  56   }
  57 
  58   public ObjectMonitor(Address addr) {
  59     super(addr);
  60   }
  61 
  62   public Mark header() {
  63     return new Mark(addr.addOffsetTo(headerFieldOffset));
  64   }
  65 
  66   // FIXME
  67   //  void      set_header(markOop hdr);
  68 
  69   // FIXME: must implement and delegate to platform-dependent implementation
  70   //  public boolean isBusy();
  71   public boolean isEntered(sun.jvm.hotspot.runtime.Thread current) {
  72     Address o = owner();
  73     if (current.threadObjectAddress().equals(o) ||
  74         current.isLockOwned(o)) {
  75       return true;
  76     }
  77     return false;
  78   }
  79 
  80   public Address owner() { return addr.getAddressAt(ownerFieldOffset); }
  81   // FIXME
  82   //  void      set_owner(void* owner);
  83 
  84   public int    waiters() { return waitersField.getValue(addr); }
  85 
  86   public Address freeNext() { return addr.getAddressAt(FreeNextFieldOffset); }
  87   // FIXME
  88   //  void      set_queue(void* owner);
  89 
  90   public int count() { return countField.getValue(addr); }
  91   // FIXME
  92   //  void      set_count(int count);
  93 
  94   public long recursions() { return recursionsField.getValue(addr); }
  95 
  96   public OopHandle object() {
  97     return addr.getOopHandleAt(objectFieldOffset);
  98   }
  99 
 100   // contentions is always equal to count
 101   public int contentions() {
 102       return count();
 103   }
 104 
 105   // FIXME
 106   //  void*     object_addr();
 107   //  void      set_object(void* obj);
 108 
 109   // The following four either aren't expressed as typed fields in
 110   // vmStructs.cpp because they aren't strongly typed in the VM, or
 111   // would confuse the SA's type system.
 112   private static ObjectHeap    heap;
 113   private static long          headerFieldOffset;
 114   private static long          objectFieldOffset;
 115   private static long          ownerFieldOffset;
 116   private static long          FreeNextFieldOffset;
 117   private static JIntField     countField;
 118   private static JIntField     waitersField;
 119   private static CIntegerField recursionsField;
 120   // FIXME: expose platform-dependent stuff
 121 }