1 /*
   2  * Copyright (c) 2018, 2019, 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.z;
  26 
  27 import sun.jvm.hotspot.debugger.Address;
  28 import sun.jvm.hotspot.runtime.VM;
  29 import sun.jvm.hotspot.runtime.VMObject;
  30 import sun.jvm.hotspot.types.AddressField;
  31 import sun.jvm.hotspot.types.Type;
  32 import sun.jvm.hotspot.types.TypeDataBase;
  33 
  34 public class ZAddressRangeMapForPageTable  extends VMObject {
  35     private static AddressField mapField;
  36 
  37     private static long AddressRangeShift = ZGlobals.ZPageSizeMinShift;
  38 
  39     static {
  40         VM.registerVMInitializedObserver((o, d) -> initialize(VM.getVM().getTypeDataBase()));
  41     }
  42 
  43     static private synchronized void initialize(TypeDataBase db) {
  44         Type type = db.lookupType("ZAddressRangeMapForPageTable");
  45 
  46         mapField = type.getAddressField("_map");
  47     }
  48 
  49     public ZAddressRangeMapForPageTable(Address addr) {
  50         super(addr);
  51     }
  52 
  53     private Address map() {
  54         return mapField.getValue(addr);
  55     }
  56 
  57     public long size() {
  58         return ZGlobals.ZAddressOffsetMax >> AddressRangeShift;
  59     }
  60 
  61     private long index_for_addr(Address addr) {
  62         long index = ZAddress.offset(addr) >> AddressRangeShift;
  63 
  64         return index;
  65     }
  66 
  67     Address at(long index) {
  68         return map().getAddressAt(index * VM.getVM().getBytesPerLong());
  69     }
  70 
  71     Address get(Address addr) {
  72         long index = index_for_addr(addr);
  73         return at(index);
  74     }
  75 
  76     public class Iterator {
  77         private long next = 0;
  78 
  79         boolean hasNext() {
  80             return next < size();
  81         }
  82 
  83         Address next() {
  84             if (next >= size()) {
  85                 throw new RuntimeException("OOIBE");
  86             }
  87 
  88             return at(next++);
  89         }
  90     }
  91 }