| /* |
| * Copyright (c) 2017, Red Hat Inc. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| import java.lang.reflect.Field; |
| |
| /** |
| * @test |
| * @bug 8175887 |
| * @summary C1 value numbering handling of Unsafe.get*Volatile is incorrect |
| * @modules java.base/jdk.internal.misc |
| * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TieredStopAtLevel=1 UnsafeVolatileGuardTest |
| */ |
| public class UnsafeVolatileGuardTest { |
| volatile static private int a; |
| static private int b; |
| |
| static final jdk.internal.misc.Unsafe UNSAFE = jdk.internal.misc.Unsafe.getUnsafe(); |
| |
| static final Object BASE; |
| static final long OFFSET; |
| |
| static { |
| try { |
| Field f = UnsafeVolatileGuardTest.class.getDeclaredField("a"); |
| BASE = UNSAFE.staticFieldBase(f); |
| OFFSET = UNSAFE.staticFieldOffset(f); |
| } catch (Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| static void test() { |
| int tt = b; // makes the JVM CSE the value of b |
| |
| while (UNSAFE.getIntVolatile(BASE, OFFSET) == 0) {} // burn |
| if (b == 0) { |
| System.err.println("wrong value of b"); |
| System.exit(1); // fail hard to report the error |
| } |
| } |
| |
| public static void main(String [] args) throws Exception { |
| for (int i = 0; i < 10; i++) { |
| new Thread(UnsafeVolatileGuardTest::test).start(); |
| } |
| b = 1; |
| a = 1; |
| } |
| } |