/*
* Copyright 2009 D.E. Shaw. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/**
* @test
* @bug 6912517
* @summary JIT bug compiles out (and stops running) code that needs to be run. Causes NPE.
*
* @run main/othervm -Xbatch -XX:CompileThreshold=100 -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops Test
*/
/**
* Highlights a bug with the JIT compiler.
* @author Matt Bruce m b r u c e __\at/__ g m a i l DOT c o m
*/
public class Test implements Runnable
{
private final Thread myThread;
private Thread myInitialThread;
private boolean myShouldCheckThreads;
/**
* Sets up the running thread, and starts it.
*/
public Test(int id)
{
myThread = new Thread(this);
myThread.setName("Runner: " + id);
myThread.start();
myShouldCheckThreads = false;
}
/**
* @param shouldCheckThreads the shouldCheckThreads to set
*/
public void setShouldCheckThreads(boolean shouldCheckThreads)
{
myShouldCheckThreads = shouldCheckThreads;
}
/**
* Starts up the two threads with enough delay between them for JIT to
* kick in.
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
// let this run for a bit, so the "run" below is JITTed.
for (int id = 0; id < 20; id++) {
System.out.println("Starting thread: " + id);
Test bug = new Test(id);
bug.setShouldCheckThreads(true);
Thread.sleep(2500);
}
}
/**
* @see java.lang.Runnable#run()
*/
public void run()
{
long runNumber = 0;
while (true) {
// run hot for a little while, give JIT time to kick in to this loop.
// then run less hot.
if (runNumber > 15000) {
try {
Thread.sleep(5);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
runNumber++;
ensureProperCallingThread();
}
}
private void ensureProperCallingThread()
{
// this should never be null. but with the JIT bug, it will be.
// JIT BUG IS HERE ==>>>>>
if (myShouldCheckThreads) {
if (myInitialThread == null) {
myInitialThread = Thread.currentThread();
}
else if (myInitialThread != Thread.currentThread()) {
System.out.println("Not working: " + myInitialThread.getName());
}
}
}
}