Mercurial > hg > Members > kono > jpf-core

comparison src/main/gov/nasa/jpf/vm/ReferenceFieldInfo.java @ 0:61d41facf527

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initial v8 import (history reset)
author Peter Mehlitz <Peter.C.Mehlitz@nasa.gov>
date Fri, 23 Jan 2015 10:14:01 -0800
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1 /*
2 * Copyright (C) 2014, United States Government, as represented by the
3 * Administrator of the National Aeronautics and Space Administration.
4 * All rights reserved.
5 *
6 * The Java Pathfinder core (jpf-core) platform is licensed under the
7 * Apache License, Version 2.0 (the "License"); you may not use this file except
8 * in compliance with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0.
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package gov.nasa.jpf.vm;
19
20 import gov.nasa.jpf.JPFException;
21
22
23 /**
24 * field info for object fields
25 */
26 public class ReferenceFieldInfo extends SingleSlotFieldInfo {
27 int init; // = MJIEnv.NULL; // not required for MJIEnv.NULL = 0
28
29 String sInit; // <2do> pcm - just a temporary quirk to init from string literals
30 // check if there are other non-object reference inits
31
32 public ReferenceFieldInfo (String name, String type, int modifiers) {
33 super(name, type, modifiers);
34 }
35
36 @Override
37 public String valueToString (Fields f) {
38 int i = f.getIntValue(storageOffset);
39 if (i == MJIEnv.NULL) {
40 return "null";
41 } else {
42 return (VM.getVM().getHeap().get(i)).toString();
43 }
44 }
45
46 @Override
47 public boolean isReference () {
48 return true;
49 }
50
51 @Override
52 public Class<? extends ChoiceGenerator<?>> getChoiceGeneratorType() {
53 return ReferenceChoiceGenerator.class;
54 }
55
56 @Override
57 public boolean isArrayField () {
58 return ci.isArray;
59 }
60
61 @Override
62 public void setConstantValue (Object constValue){
63 // <2do> pcm - check what other constants we might encounter, this is most
64 // probably not just used for Strings.
65 // Besides the type issue, there is an even bigger problem with identities.
66 // For instance, all String refs initialized via the same string literal
67 // inside a single classfile are in fact refering to the same object. This
68 // means we have to keep a registry (hashtab) with string-literal created
69 // String objects per ClassInfo, and use this when we assign or init
70 // String references.
71 // For the sake of progress, we ignore this for now, but have to come back
72 // to it because it violates the VM spec
73
74 if (constValue instanceof String){
75 cv = constValue;
76 sInit = (String)constValue;
77 } else {
78 throw new JPFException ("unsupported reference initialization: " + constValue);
79 }
80 }
81
82 @Override
83 public void initialize (ElementInfo ei, ThreadInfo ti) {
84 int ref = init;
85 if (sInit != null) {
86 VM vm = ti.getVM();
87 Heap heap = vm.getHeap();
88 ref = heap.newString(sInit, ti).getObjectRef();
89 }
90 ei.getFields().setReferenceValue( storageOffset, ref);
91 }
92
93 @Override
94 public Object getValueObject (Fields f){
95 int i = f.getIntValue(storageOffset);
96 if (i == MJIEnv.NULL) {
97 return null;
98 } else {
99 Heap heap = VM.getVM().getHeap();
100 return heap.get(i);
101 }
102 }
103 }