1 /*
   2  * Copyright (c) 2003, 2015, 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.parallel;
  26 
  27 import java.io.*;
  28 import java.util.*;
  29 
  30 import sun.jvm.hotspot.debugger.*;
  31 import sun.jvm.hotspot.memory.*;
  32 import sun.jvm.hotspot.runtime.*;
  33 import sun.jvm.hotspot.types.*;
  34 
  35 public abstract class ImmutableSpace 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) {
  45       Type type = db.lookupType("ImmutableSpace");
  46       bottomField = type.getAddressField("_bottom");
  47       endField    = type.getAddressField("_end");
  48    }
  49 
  50    public ImmutableSpace(Address addr) {
  51       super(addr);
  52    }
  53 
  54    // Fields
  55    private static AddressField bottomField;
  56    private static AddressField endField;
  57 
  58    // Accessors
  59    public Address   bottom()       { return bottomField.getValue(addr); }
  60    public Address   end()          { return endField.getValue(addr);    }
  61 
  62    /** Returns a subregion of the space containing all the objects in
  63       the space. */
  64    public MemRegion usedRegion() {
  65       return new MemRegion(bottom(), end());
  66    }
  67 
  68    /** Support for iteration over heap -- not sure how this will
  69       interact with GC in reflective system, but necessary for the
  70       debugging mechanism */
  71    public OopHandle bottomAsOopHandle() {
  72       return bottomField.getOopHandle(addr);
  73    }
  74 
  75    /** returns all MemRegions where live objects are */
  76    public abstract List/*<MemRegion>*/ getLiveRegions();
  77 
  78    /** Returned value is in bytes */
  79    public long capacity() { return end().minus(bottom()); }
  80 
  81    public abstract long used();
  82 
  83    /** Testers */
  84    public boolean contains(Address p) {
  85       return (bottom().lessThanOrEqual(p) && end().greaterThan(p));
  86    }
  87 
  88    public void print() { printOn(System.out); }
  89    public abstract void printOn(PrintStream tty);
  90 }