2 * Copyright (C) 2014, United States Government, as represented by the
3 * Administrator of the National Aeronautics and Space Administration.
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
10 * http://www.apache.org/licenses/LICENSE-2.0.
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.
18 package gov.nasa.jpf.jvm.bytecode;
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.Scheduler;
24 import gov.nasa.jpf.vm.StackFrame;
25 import gov.nasa.jpf.vm.ThreadInfo;
28 * Exit monitor for object
29 * ..., objectref => ...
31 public class MONITOREXIT extends LockInstruction {
34 public Instruction execute (ThreadInfo ti) {
35 boolean didUnblock = false;
36 StackFrame frame = ti.getTopFrame();
37 Scheduler scheduler = ti.getScheduler();
39 int objref = frame.peek();
40 if (objref == MJIEnv.NULL) {
41 return ti.createAndThrowException("java.lang.NullPointerException", "attempt to release lock for null object");
45 ElementInfo ei = ti.getElementInfo(objref);
46 ei = scheduler.updateObjectSharedness(ti, ei, null); // locks most likely belong to shared objects
48 if (!ti.isFirstStepInsn()){
49 ei = ei.getModifiableInstance();
50 // we only do this in the top half of the first execution, but before potentially creating
51 // a CG so that blocked threads are runnable again
52 didUnblock = ei.unlock(ti);
55 if (ei.getLockCount() == 0) { // might still be recursively locked, which wouldn't be a release
56 if (scheduler.setsLockReleaseCG(ti, ei, didUnblock)){ // scheduling point
61 // bottom half or monitorexit proceeded
62 frame = ti.getModifiableTopFrame();
69 public int getByteCode () {
74 public void accept(JVMInstructionVisitor insVisitor) {
75 insVisitor.visit(this);