1 /* 2 * Copyright 2009 D.E. Shaw. All Rights Reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /** 25 * @test 26 * @bug 6912517 27 * @summary JIT bug compiles out (and stops running) code that needs to be run. Causes NPE. 28 * 29 * @run main/othervm -Xbatch -XX:CompileThreshold=100 -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops 30 * compiler.c2.Test6912517 31 */ 32 33 package compiler.c2; 34 35 /** 36 * Highlights a bug with the JIT compiler. 37 * @author Matt Bruce m b r u c e __\at/__ g m a i l DOT c o m 38 */ 39 public class Test6912517 implements Runnable 40 { 41 private final Thread myThread; 42 private Thread myInitialThread; 43 private boolean myShouldCheckThreads; 44 45 /** 46 * Sets up the running thread, and starts it. 47 */ 48 public Test6912517(int id) 49 { 50 myThread = new Thread(this); 51 myThread.setName("Runner: " + id); 52 myThread.start(); 53 myShouldCheckThreads = false; 54 } 55 56 /** 57 * @param shouldCheckThreads the shouldCheckThreads to set 58 */ 59 public void setShouldCheckThreads(boolean shouldCheckThreads) 60 { 61 myShouldCheckThreads = shouldCheckThreads; 62 } 63 64 /** 65 * Starts up the two threads with enough delay between them for JIT to 66 * kick in. 67 * @param args 68 * @throws InterruptedException 69 */ 70 public static void main(String[] args) throws InterruptedException 71 { 72 // let this run for a bit, so the "run" below is JITTed. 73 for (int id = 0; id < 20; id++) { 74 System.out.println("Starting thread: " + id); 75 Test6912517 bug = new Test6912517(id); 76 bug.setShouldCheckThreads(true); 77 Thread.sleep(2500); 78 } 79 } 80 81 /** 82 * @see java.lang.Runnable#run() 83 */ 84 public void run() 85 { 86 long runNumber = 0; 87 while (true) { 88 // run hot for a little while, give JIT time to kick in to this loop. 89 // then run less hot. 90 if (runNumber > 15000) { 91 try { 92 Thread.sleep(5); 93 } 94 catch (InterruptedException e) { 95 e.printStackTrace(); 96 } 97 } 98 runNumber++; 99 ensureProperCallingThread(); 100 } 101 } 102 103 private void ensureProperCallingThread() 104 { 105 // this should never be null. but with the JIT bug, it will be. 106 // JIT BUG IS HERE ==>>>>> 107 if (myShouldCheckThreads) { 108 if (myInitialThread == null) { 109 myInitialThread = Thread.currentThread(); 110 } 111 else if (myInitialThread != Thread.currentThread()) { 112 System.out.println("Not working: " + myInitialThread.getName()); 113 } 114 } 115 } 116 }