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.compareAndSetObject(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 }