1 /*
   2  * Copyright (c) 2000, 2011, 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.oops;
  26 
  27 import java.io.*;
  28 import java.util.*;
  29 import sun.jvm.hotspot.debugger.*;
  30 import sun.jvm.hotspot.runtime.*;
  31 import sun.jvm.hotspot.types.*;
  32 import sun.jvm.hotspot.utilities.*;
  33 
  34 //  ConstantPoolCache : A constant pool cache (constantPoolCacheOopDesc).
  35 //  See cpCacheOop.hpp for details about this class.
  36 //
  37 public class ConstantPoolCache extends Oop {
  38   static {
  39     VM.registerVMInitializedObserver(new Observer() {
  40         public void update(Observable o, Object data) {
  41           initialize(VM.getVM().getTypeDataBase());
  42         }
  43       });
  44   }
  45 
  46   private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
  47     Type type      = db.lookupType("constantPoolCacheOopDesc");
  48     constants      = new OopField(type.getOopField("_constant_pool"), 0);
  49     baseOffset     = type.getSize();
  50     Type elType    = db.lookupType("ConstantPoolCacheEntry");
  51     elementSize    = elType.getSize();
  52     length         = new CIntField(type.getCIntegerField("_length"), 0);
  53   }
  54 
  55   ConstantPoolCache(OopHandle handle, ObjectHeap heap) {
  56     super(handle, heap);
  57   }
  58 
  59   public boolean isConstantPoolCache() { return true; }
  60 
  61   private static OopField constants;
  62 
  63   private static long baseOffset;
  64   private static long elementSize;
  65   private static CIntField length;
  66 
  67 
  68   public ConstantPool getConstants() { return (ConstantPool) constants.getValue(this); }
  69 
  70   public long getObjectSize() {
  71     return alignObjectSize(baseOffset + getLength() * elementSize);
  72   }
  73 
  74   public ConstantPoolCacheEntry getEntryAt(int i) {
  75     if (i < 0 || i >= getLength()) throw new IndexOutOfBoundsException(i + " " + getLength());
  76     return new ConstantPoolCacheEntry(this, i);
  77   }
  78 
  79   public static boolean isSecondaryIndex(int i)     { return (i < 0); }
  80   public static int     decodeSecondaryIndex(int i) { return  isSecondaryIndex(i) ? ~i : i; }
  81   public static int     encodeSecondaryIndex(int i) { return !isSecondaryIndex(i) ? ~i : i; }
  82 
  83   // secondary entries hold invokedynamic call site bindings
  84   public ConstantPoolCacheEntry getSecondaryEntryAt(int i) {
  85     int rawIndex = i;
  86     if (isSecondaryIndex(i)) {
  87       rawIndex = decodeSecondaryIndex(i);
  88     }
  89     ConstantPoolCacheEntry e = getEntryAt(rawIndex);
  90     if (Assert.ASSERTS_ENABLED) {
  91       Assert.that(e.isSecondaryEntry(), "must be a secondary entry:" + rawIndex);
  92     }
  93     return e;
  94   }
  95 
  96   public ConstantPoolCacheEntry getMainEntryAt(int i) {
  97     int primaryIndex = i;
  98     if (isSecondaryIndex(i)) {
  99       // run through an extra level of indirection:
 100       int rawIndex = decodeSecondaryIndex(i);
 101       primaryIndex = getEntryAt(rawIndex).getMainEntryIndex();
 102     }
 103     ConstantPoolCacheEntry e = getEntryAt(primaryIndex);
 104     if (Assert.ASSERTS_ENABLED) {
 105       Assert.that(!e.isSecondaryEntry(), "must not be a secondary entry:" + primaryIndex);
 106     }
 107     return e;
 108   }
 109 
 110   public int getIntAt(int entry, int fld) {
 111     //alignObjectSize ?
 112     long offset = baseOffset + /*alignObjectSize*/entry * elementSize + fld* getHeap().getIntSize();
 113     return (int) getHandle().getCIntegerAt(offset, getHeap().getIntSize(), true );
 114   }
 115 
 116 
 117   public void printValueOn(PrintStream tty) {
 118     tty.print("ConstantPoolCache for " + getConstants().getPoolHolder().getName().asString());
 119   }
 120 
 121   public int getLength() {
 122     return (int) length.getValue(this);
 123   }
 124 
 125   public void iterateFields(OopVisitor visitor, boolean doVMFields) {
 126     super.iterateFields(visitor, doVMFields);
 127     if (doVMFields) {
 128       visitor.doOop(constants, true);
 129       for (int i = 0; i < getLength(); i++) {
 130         ConstantPoolCacheEntry entry = getEntryAt(i);
 131         entry.iterateFields(visitor);
 132       }
 133     }
 134   }
 135 };