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 * @bug 8167298 27 * @summary Unsafe.compareAndExchangeObject should keep track of returned type after matching 28 * @modules java.base/jdk.internal.misc 29 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:-UseCompressedOops TestCAEAntiDep 30 * 31 */ 32 33 import java.lang.reflect.Field; 34 import jdk.internal.misc.Unsafe; 35 36 public class TestCAEAntiDep { 37 static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe(); 38 static final long O_OFFSET; 39 40 static class C { 41 int f1; 42 } 43 44 C o = new C(); 45 46 static { 47 try { 48 Field oField = TestCAEAntiDep.class.getDeclaredField("o"); 49 O_OFFSET = UNSAFE.objectFieldOffset(oField); 50 } catch (Exception e) { 51 throw new RuntimeException(e); 52 } 53 } 54 55 static int m(TestCAEAntiDep test, Object expected, Object x) { 56 C old = (C)UNSAFE.compareAndExchangeObjectVolatile(test, O_OFFSET, expected, x); 57 int res = old.f1; 58 old.f1 = 0x42; 59 return res; 60 } 61 62 static public void main(String[] args) { 63 TestCAEAntiDep test = new TestCAEAntiDep(); 64 for (int i = 0; i < 20000; i++) { 65 m(test, test.o, test.o); 66 } 67 } 68 }