1 /* 2 * Copyright (c) 2017, Red Hat Inc. 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 7170145 27 * @summary C1 doesn't respect the JMM with volatile field loads 28 * 29 * @run main/othervm -XX:TieredStopAtLevel=1 VolatileAcquireTest 30 */ 31 public class VolatileAcquireTest { 32 volatile static private int a; 33 static private int b; 34 35 public static void main(String [] args) throws Exception { 36 for (int i = 0; i < 100; i++) { 37 new Thread() { 38 39 @Override 40 public void run() { 41 int tt = b; // makes the JVM CSE the value of b 42 43 while (a == 0) {} // burn 44 if (b == 0) { 45 System.out.println("error"); 46 System.exit(1); // fail hard 47 } 48 } 49 50 }.start(); 51 } 52 53 b = 1; 54 a = 1; 55 } 56 }