Mercurial > hg > Members > kono > jpf-core
view src/main/gov/nasa/jpf/vm/ReferenceFieldInfo.java @ 0:61d41facf527
initial v8 import (history reset)
author | Peter Mehlitz <Peter.C.Mehlitz@nasa.gov> |
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date | Fri, 23 Jan 2015 10:14:01 -0800 |
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/* * Copyright (C) 2014, United States Government, as represented by the * Administrator of the National Aeronautics and Space Administration. * All rights reserved. * * The Java Pathfinder core (jpf-core) platform is licensed under the * Apache License, Version 2.0 (the "License"); you may not use this file except * in compliance with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0. * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package gov.nasa.jpf.vm; import gov.nasa.jpf.JPFException; /** * field info for object fields */ public class ReferenceFieldInfo extends SingleSlotFieldInfo { int init; // = MJIEnv.NULL; // not required for MJIEnv.NULL = 0 String sInit; // <2do> pcm - just a temporary quirk to init from string literals // check if there are other non-object reference inits public ReferenceFieldInfo (String name, String type, int modifiers) { super(name, type, modifiers); } @Override public String valueToString (Fields f) { int i = f.getIntValue(storageOffset); if (i == MJIEnv.NULL) { return "null"; } else { return (VM.getVM().getHeap().get(i)).toString(); } } @Override public boolean isReference () { return true; } @Override public Class<? extends ChoiceGenerator<?>> getChoiceGeneratorType() { return ReferenceChoiceGenerator.class; } @Override public boolean isArrayField () { return ci.isArray; } @Override public void setConstantValue (Object constValue){ // <2do> pcm - check what other constants we might encounter, this is most // probably not just used for Strings. // Besides the type issue, there is an even bigger problem with identities. // For instance, all String refs initialized via the same string literal // inside a single classfile are in fact refering to the same object. This // means we have to keep a registry (hashtab) with string-literal created // String objects per ClassInfo, and use this when we assign or init // String references. // For the sake of progress, we ignore this for now, but have to come back // to it because it violates the VM spec if (constValue instanceof String){ cv = constValue; sInit = (String)constValue; } else { throw new JPFException ("unsupported reference initialization: " + constValue); } } @Override public void initialize (ElementInfo ei, ThreadInfo ti) { int ref = init; if (sInit != null) { VM vm = ti.getVM(); Heap heap = vm.getHeap(); ref = heap.newString(sInit, ti).getObjectRef(); } ei.getFields().setReferenceValue( storageOffset, ref); } @Override public Object getValueObject (Fields f){ int i = f.getIntValue(storageOffset); if (i == MJIEnv.NULL) { return null; } else { Heap heap = VM.getVM().getHeap(); return heap.get(i); } } }