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 }