1 /*

     2  * Copyright (c) 2017, 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 8186125

    27  * @summary cast before unsafe access moved in dominating null check null path causes crash

    28  * @modules java.base/jdk.internal.misc:+open

    29  *

    30  * @run main/othervm -XX:-BackgroundCompilation TestSplitIf

    31  *

    32  */

    33 

    34 import jdk.internal.misc.Unsafe;

    35 import java.lang.reflect.Field;

    36 

    37 public class TestSplitIf {

    38 

    39     static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();

    40     static final long F_OFFSET;

    41 

    42     static class A {

    43         int f;

    44         A(int f) {

    45             this.f = f;

    46         }

    47     }

    48 

    49     static {

    50         try {

    51             Field fField = A.class.getDeclaredField("f");

    52             F_OFFSET = UNSAFE.objectFieldOffset(fField);

    53         } catch (Exception e) {

    54             throw new RuntimeException(e);

    55         }

    56     }

    57 

    58     static int test(A a1, A a2, boolean flag1) {

    59         boolean flag2;

    60         int f = 0;

    61         A a = null;

    62         if (flag1) {

    63             flag2 = true;

    64             a = a1;

    65         } else {

    66             flag2 = false;

    67             a = a2;

    68         }

    69         if (flag2) {

    70             f = UNSAFE.getInt(a, F_OFFSET);

    71         } else {

    72             f = UNSAFE.getInt(a, F_OFFSET);

    73         }

    74         return f;

    75     }

    76 

    77     static public void main(String[] args) {

    78         A a = new A(0x42);

    79         for (int i = 0; i < 20000; i++) {

    80             test(a, a, (i % 2) == 0);

    81         }

    82     }

    83 

    84 }