TestMemBarAcquire.java revision 11707:ad7af1afda7a 
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
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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
32package compiler.membars;
33
34public 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
58