1 /* 2 * Copyright (c) 2016, 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 * @test 25 * @bug 8134918 26 * @modules java.base/jdk.internal.misc 27 * 28 * @run main/bootclasspath/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TypeProfileLevel=222 -XX:+UseTypeSpeculation -Xbatch 29 * -XX:CompileCommand=dontinline,compiler.profiling.UnsafeAccess::test* 30 * compiler.profiling.UnsafeAccess 31 */ 32 33 package compiler.profiling; 34 35 import jdk.internal.misc.Unsafe; 36 37 public class UnsafeAccess { 38 private static final Unsafe U = Unsafe.getUnsafe(); 39 40 static Class cls = Object.class; 41 static long off = U.ARRAY_OBJECT_BASE_OFFSET; 42 43 static Object testUnsafeAccess(Object o, boolean isObjArray) { 44 if (o != null && cls.isInstance(o)) { // speculates "o" type to int[] 45 return helperUnsafeAccess(o, isObjArray); 46 } 47 return null; 48 } 49 50 static Object helperUnsafeAccess(Object o, boolean isObjArray) { 51 if (isObjArray) { 52 U.putObject(o, off, new Object()); 53 } 54 return o; 55 } 56 57 static Object testUnsafeLoadStore(Object o, boolean isObjArray) { 58 if (o != null && cls.isInstance(o)) { // speculates "o" type to int[] 59 return helperUnsafeLoadStore(o, isObjArray); 60 } 61 return null; 62 } 63 64 static Object helperUnsafeLoadStore(Object o, boolean isObjArray) { 65 if (isObjArray) { 66 Object o1 = U.getObject(o, off); 67 U.compareAndSwapObject(o, off, o1, new Object()); 68 } 69 return o; 70 } 71 72 public static void main(String[] args) { 73 Object[] objArray = new Object[10]; 74 int[] intArray = new int[10]; 75 76 for (int i = 0; i < 20_000; i++) { 77 helperUnsafeAccess(objArray, true); 78 } 79 for (int i = 0; i < 20_000; i++) { 80 testUnsafeAccess(intArray, false); 81 } 82 83 for (int i = 0; i < 20_000; i++) { 84 helperUnsafeLoadStore(objArray, true); 85 } 86 for (int i = 0; i < 20_000; i++) { 87 testUnsafeLoadStore(intArray, false); 88 } 89 90 System.out.println("TEST PASSED"); 91 } 92 }