1 /* 2 * Copyright (c) 2016, 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 * @summary Clearing control during final graph reshape causes memory barrier to loose dependency on null check 27 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:+UseShenandoahGC -XX:-TieredCompilation -XX:+UnlockDiagnosticVMOptions -XX:+StressLCM -XX:+StressGCM TestWriteBarrierClearControl 28 * 29 */ 30 public class TestWriteBarrierClearControl { 31 32 int f; 33 34 static void test1(TestWriteBarrierClearControl o) { 35 o.f = 0x42; 36 } 37 38 static TestWriteBarrierClearControl fo = new TestWriteBarrierClearControl(); 39 40 static void test2() { 41 TestWriteBarrierClearControl o = fo; 42 o.f = 0x42; 43 } 44 45 static public void main(String[] args) { 46 TestWriteBarrierClearControl o = new TestWriteBarrierClearControl(); 47 for (int i = 0; i < 20000; i++) { 48 test1(o); 49 test2(); 50 } 51 try { 52 test1(null); 53 } catch(NullPointerException npe) {} 54 fo = null; 55 try { 56 test2(); 57 } catch(NullPointerException npe) {} 58 } 59 }