1 /*
   2  * Copyright (c) 2000, 2013, 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.io.*;
  28 import java.util.*;
  29 import sun.jvm.hotspot.debugger.*;
  30 import sun.jvm.hotspot.oops.*;
  31 import sun.jvm.hotspot.types.*;
  32 
  33 /** <P> ThreadLocalAllocBuffer: a descriptor for thread-local storage
  34     used by the threads for allocation. </P>
  35 
  36     <P> It is thread-private at any time, but maybe multiplexed over
  37     time across multiple threads. </P> */
  38 
  39 public class ThreadLocalAllocBuffer extends VMObject {
  40   private static AddressField  startField;
  41   private static AddressField  topField;
  42   private static AddressField  endField;
  43   private static CIntegerField desired_sizeField;
  44 
  45   static {
  46     VM.registerVMInitializedObserver(new Observer() {
  47         public void update(Observable o, Object data) {
  48           initialize(VM.getVM().getTypeDataBase());
  49         }
  50       });
  51   }
  52 
  53   private static synchronized void initialize(TypeDataBase db) {
  54     Type type = db.lookupType("ThreadLocalAllocBuffer");
  55 
  56     startField         = type.getAddressField("_start");
  57     topField           = type.getAddressField("_top");
  58     endField           = type.getAddressField("_end");
  59     desired_sizeField          = type.getCIntegerField("_desired_size");
  60   }
  61 
  62   public ThreadLocalAllocBuffer(Address addr) {
  63     super(addr);
  64   }
  65 
  66   public Address start()    { return startField.getValue(addr); }
  67   public Address end()      { return   endField.getValue(addr); }
  68   public Address top()      { return   topField.getValue(addr); }
  69   public Address hardEnd()  { return end().addOffsetTo(alignmentReserve()); }
  70 
  71   private long alignmentReserve() {
  72     return Oop.alignObjectSize(endReserve());
  73   }
  74 
  75   private long endReserve() {
  76     long minFillerArraySize = Array.baseOffsetInBytes(BasicType.T_INT);
  77     long reserveForAllocationPrefetch = VM.getVM().getReserveForAllocationPrefetch();
  78     long heapWordSize = VM.getVM().getHeapWordSize();
  79 
  80     return Math.max(minFillerArraySize, reserveForAllocationPrefetch * heapWordSize);
  81   }
  82 
  83   /** Support for iteration over heap -- not sure how this will
  84       interact with GC in reflective system, but necessary for the
  85       debugging mechanism */
  86   public OopHandle startAsOopHandle() {
  87     return startField.getOopHandle(addr);
  88   }
  89 
  90   /** Support for iteration over heap -- not sure how this will
  91       interact with GC in reflective system, but necessary for the
  92       debugging mechanism */
  93   public OopHandle nextOopHandle(OopHandle handle, long size) {
  94     return handle.addOffsetToAsOopHandle(size);
  95   }
  96 
  97   //  public int     size();           // FIXME: must adjust this to be in bytes
  98   //  public int     availableSize();  // FIXME: must adjust this to be in bytes
  99   public void print() {
 100     printOn(System.out);
 101   }
 102 
 103   public boolean contains(Address p) {
 104     if (top() == null) {
 105       return false;
 106     }
 107     return (start().lessThanOrEqual(p) && top().greaterThan(p));
 108   }
 109 
 110   public void printOn(PrintStream tty) {
 111     tty.println(" [" + start() + "," +
 112                 top() + "," + end() + ",{" + hardEnd() + "})");
 113   }
 114 }