kvn@1586: /*
kvn@1586:  * Copyright 2009 D.E. Shaw.  All Rights Reserved.
kvn@1586:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
kvn@1586:  *
kvn@1586:  * This code is free software; you can redistribute it and/or modify it
kvn@1586:  * under the terms of the GNU General Public License version 2 only, as
kvn@1586:  * published by the Free Software Foundation.
kvn@1586:  *
kvn@1586:  * This code is distributed in the hope that it will be useful, but WITHOUT
kvn@1586:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
kvn@1586:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
kvn@1586:  * version 2 for more details (a copy is included in the LICENSE file that
kvn@1586:  * accompanied this code).
kvn@1586:  *
kvn@1586:  * You should have received a copy of the GNU General Public License version
kvn@1586:  * 2 along with this work; if not, write to the Free Software Foundation,
kvn@1586:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
kvn@1586:  *
kvn@1586:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
kvn@1586:  * CA 95054 USA or visit www.sun.com if you need additional information or
kvn@1586:  * have any questions.
kvn@1586:  */
kvn@1586: 
kvn@1586: /**
kvn@1586:  * @test
kvn@1586:  * @bug 6912517
kvn@1586:  * @summary JIT bug compiles out (and stops running) code that needs to be run.  Causes NPE.
kvn@1586:  *
kvn@1586:  * @run main/othervm -Xbatch -XX:CompileThreshold=100 -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops Test
kvn@1586:  */
kvn@1586: 
kvn@1586: /**
kvn@1586:  * Highlights a bug with the JIT compiler.
kvn@1586:  * @author Matt Bruce m b r u c e __\at/__ g m a i l DOT c o m
kvn@1586:  */
kvn@1586: public class Test implements Runnable
kvn@1586: {
kvn@1586:     private final Thread myThread;
kvn@1586:     private Thread       myInitialThread;
kvn@1586:     private boolean      myShouldCheckThreads;
kvn@1586: 
kvn@1586:     /**
kvn@1586:      * Sets up the running thread, and starts it.
kvn@1586:      */
kvn@1586:     public Test(int id)
kvn@1586:     {
kvn@1586:         myThread = new Thread(this);
kvn@1586:         myThread.setName("Runner: " + id);
kvn@1586:         myThread.start();
kvn@1586:         myShouldCheckThreads = false;
kvn@1586:     }
kvn@1586: 
kvn@1586:     /**
kvn@1586:      * @param shouldCheckThreads the shouldCheckThreads to set
kvn@1586:      */
kvn@1586:     public void setShouldCheckThreads(boolean shouldCheckThreads)
kvn@1586:     {
kvn@1586:         myShouldCheckThreads = shouldCheckThreads;
kvn@1586:     }
kvn@1586: 
kvn@1586:     /**
kvn@1586:      * Starts up the two threads with enough delay between them for JIT to
kvn@1586:      * kick in.
kvn@1586:      * @param args
kvn@1586:      * @throws InterruptedException
kvn@1586:      */
kvn@1586:     public static void main(String[] args) throws InterruptedException
kvn@1586:     {
kvn@1586:         // let this run for a bit, so the "run" below is JITTed.
kvn@1586:         for (int id = 0; id < 20; id++) {
kvn@1586:             System.out.println("Starting thread: " + id);
kvn@1586:             Test bug = new Test(id);
kvn@1586:             bug.setShouldCheckThreads(true);
kvn@1586:             Thread.sleep(2500);
kvn@1586:         }
kvn@1586:     }
kvn@1586: 
kvn@1586:     /**
kvn@1586:      * @see java.lang.Runnable#run()
kvn@1586:      */
kvn@1586:     public void run()
kvn@1586:     {
kvn@1586:         long runNumber = 0;
kvn@1586:         while (true) {
kvn@1586:             // run hot for a little while, give JIT time to kick in to this loop.
kvn@1586:             // then run less hot.
kvn@1586:             if (runNumber > 15000) {
kvn@1586:                 try {
kvn@1586:                     Thread.sleep(5);
kvn@1586:                 }
kvn@1586:                 catch (InterruptedException e) {
kvn@1586:                     e.printStackTrace();
kvn@1586:                 }
kvn@1586:             }
kvn@1586:             runNumber++;
kvn@1586:             ensureProperCallingThread();
kvn@1586:         }
kvn@1586:     }
kvn@1586: 
kvn@1586:     private void ensureProperCallingThread()
kvn@1586:     {
kvn@1586:         // this should never be null.  but with the JIT bug, it will be.
kvn@1586:         // JIT BUG IS HERE ==>>>>>
kvn@1586:         if (myShouldCheckThreads) {
kvn@1586:             if (myInitialThread == null) {
kvn@1586:                 myInitialThread = Thread.currentThread();
kvn@1586:             }
kvn@1586:             else if (myInitialThread != Thread.currentThread()) {
kvn@1586:                 System.out.println("Not working: " + myInitialThread.getName());
kvn@1586:             }
kvn@1586:         }
kvn@1586:     }
kvn@1586: }