1 /*
   2  * Copyright (c) 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.runtime;
  26 
  27 import java.util.*;
  28 import sun.jvm.hotspot.debugger.*;
  29 import sun.jvm.hotspot.debugger.cdbg.CDebugger;
  30 import sun.jvm.hotspot.debugger.cdbg.ClosestSymbol;
  31 import sun.jvm.hotspot.debugger.cdbg.LoadObject;
  32 import sun.jvm.hotspot.types.*;
  33 import sun.jvm.hotspot.HotSpotTypeDataBase;
  34 
  35 /** Given a pointer to some memory return an appropriate wrapper.
  36  Various subclasses provide different mechanisms for identifying the
  37  appropriate wrapper. */
  38 
  39 abstract public class InstanceConstructor<T> {
  40   /** Instantiate the most-precisely typed wrapper object available
  41       for the type of the given Address. If no type in the mapping
  42       matched the type of the Address, throws a WrongTypeException.
  43       Returns null for a null address (similar behavior to
  44       VMObjectFactory). */
  45   abstract public T instantiateWrapperFor(Address addr) throws WrongTypeException;
  46 
  47   protected WrongTypeException newWrongTypeException(Address addr) {
  48     String message = "No suitable match for type of address " + addr;
  49     CDebugger cdbg = VM.getVM().getDebugger().getCDebugger();
  50     if (cdbg != null) {
  51       // Most common case: V-table pointer is the first field
  52       Address vtblPtr = addr.getAddressAt(0);
  53       LoadObject lo = cdbg.loadObjectContainingPC(vtblPtr);
  54       if (lo != null) {
  55         ClosestSymbol symbol = lo.closestSymbolToPC(vtblPtr);
  56         if (symbol != null) {
  57           message += " (nearest symbol is " + symbol.getName() + ")";
  58         }
  59       }
  60     }
  61 
  62     return new WrongTypeException(message);
  63   }
  64 }