Mercurial > hg > Members > kono > jpf-core

comparison src/main/gov/nasa/jpf/jvm/bytecode/ARRAYLENGTH.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.jvm.bytecode;
19
20 import gov.nasa.jpf.vm.ElementInfo;
21 import gov.nasa.jpf.vm.Instruction;
22 import gov.nasa.jpf.vm.MJIEnv;
23 import gov.nasa.jpf.vm.StackFrame;
24 import gov.nasa.jpf.vm.ThreadInfo;
25
26
27 /**
28 * Get length of array
29 * ..., arrayref => ..., length
30 */
31 public class ARRAYLENGTH extends Instruction implements JVMInstruction {
32
33 protected int arrayRef;
34
35 /**
36 * only makes sense from an executeInstruction() or instructionExecuted() listener,
37 * it is undefined outside of insn exec notifications
38 */
39 public int getArrayRef (ThreadInfo ti){
40 if (ti.isPreExec()){
41 return peekArrayRef(ti);
42 } else {
43 return arrayRef;
44 }
45 }
46
47 public ElementInfo peekArrayElementInfo (ThreadInfo ti){
48 int aref = getArrayRef(ti);
49 return ti.getElementInfo(aref);
50 }
51
52 @Override
53 public Instruction execute (ThreadInfo ti) {
54 StackFrame frame = ti.getModifiableTopFrame();
55
56 arrayRef = frame.pop();
57
58 if (arrayRef == MJIEnv.NULL){
59 return ti.createAndThrowException("java.lang.NullPointerException",
60 "array length of null object");
61 }
62
63 ElementInfo ei = ti.getElementInfo(arrayRef);
64 frame.push(ei.arrayLength(), false);
65
66 return getNext(ti);
67 }
68
69 @Override
70 public int getByteCode () {
71 return 0xBE;
72 }
73
74 @Override
75 public void accept(JVMInstructionVisitor insVisitor) {
76 insVisitor.visit(this);
77 }
78
79 protected int peekArrayRef (ThreadInfo ti) {
80 return ti.getTopFrame().peek();
81 }
82 }