1 /* 2 * Copyright (c) 2014, Oracle and/or its affiliates. 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 TestMemBarAcquire 26 * @bug 8048879 27 * @summary Tests optimization of MemBarAcquireNodes 28 * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation 29 * compiler.membars.TestMemBarAcquire 30 */ 31 32 package compiler.membars; 33 34 public class TestMemBarAcquire { 35 private volatile static Object defaultObj = new Object(); 36 private Object obj; 37 38 public TestMemBarAcquire(Object param) { 39 // Volatile load. MemBarAcquireNode is added after the 40 // load to prevent following loads from floating up past. 41 // StoreNode is added to store result of load in 'obj'. 42 this.obj = defaultObj; 43 // Overrides 'obj' and therefore makes previous StoreNode 44 // and the corresponding LoadNode useless. However, the 45 // LoadNode is still connected to the MemBarAcquireNode 46 // that should now release the reference. 47 this.obj = param; 48 } 49 50 public static void main(String[] args) throws Exception { 51 // Make sure TestMemBarAcquire::<init> is compiled 52 for (int i = 0; i < 100000; ++i) { 53 TestMemBarAcquire p = new TestMemBarAcquire(new Object()); 54 } 55 } 56 } 57