1 /*
   2  * Copyright (c) 2017, 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.gc.g1;
  26 
  27 import java.util.Observable;
  28 import java.util.Observer;
  29 import sun.jvm.hotspot.debugger.Address;
  30 import sun.jvm.hotspot.runtime.VM;
  31 import sun.jvm.hotspot.runtime.VMObject;
  32 import sun.jvm.hotspot.types.CIntegerField;
  33 import sun.jvm.hotspot.types.Type;
  34 import sun.jvm.hotspot.types.TypeDataBase;
  35 
  36 // Mirror class for HeapRegionType. Currently we don't actually include
  37 // any of its fields but only iterate over it.
  38 
  39 public class HeapRegionType extends VMObject {
  40 
  41     private static int freeTag;
  42 
  43     private static int youngMask;
  44 
  45     private static int humongousMask;
  46 
  47     private static int pinnedMask;
  48 
  49     private static int oldMask;
  50 
  51     private static CIntegerField tagField;
  52 
  53     private int tag;
  54 
  55     static {
  56         VM.registerVMInitializedObserver(new Observer() {
  57                 public void update(Observable o, Object data) {
  58                     initialize(VM.getVM().getTypeDataBase());
  59                 }
  60         });
  61     }
  62 
  63     private static synchronized void initialize(TypeDataBase db) {
  64         Type type = db.lookupType("HeapRegionType");
  65 
  66         tagField = type.getCIntegerField("_tag");
  67 
  68         youngMask = db.lookupIntConstant("HeapRegionType::YoungMask");
  69         humongousMask = db.lookupIntConstant("HeapRegionType::HumongousMask");
  70         oldMask = db.lookupIntConstant("HeapRegionType::OldMask");
  71     }
  72 
  73     public boolean isFree() {
  74         return tagField.getValue(addr) == freeTag;
  75     }
  76 
  77     public boolean isYoung() {
  78         return (tagField.getValue(addr) & youngMask) != 0;
  79     }
  80 
  81     public boolean isHumongous() {
  82         return (tagField.getValue(addr) & humongousMask) != 0;
  83     }
  84 
  85     public boolean isPinned() {
  86         return (tagField.getValue(addr) & pinnedMask) != 0;
  87     }
  88 
  89     public boolean isOld() {
  90         return (tagField.getValue(addr) & oldMask) != 0;
  91     }
  92 
  93     public HeapRegionType(Address addr) {
  94         super(addr);
  95     }
  96 }