1 /*

     2  * Copyright (c) 2012, 2015, 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 /*

    25  * @test

    26  * @bug 7190310

    27  * @summary Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops

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

    29  * @modules java.base/java.lang.ref:open

    30  *

    31  * @run main/othervm -Xbatch compiler.c2.Test7190310_unsafe

    32  */

    33 

    34 package compiler.c2;

    35 

    36 import jdk.internal.misc.Unsafe;

    37 

    38 import java.lang.ref.Reference;

    39 import java.lang.ref.WeakReference;

    40 import java.lang.reflect.Field;

    41 

    42 public class Test7190310_unsafe {

    43 

    44     static class TestObject {

    45         public String toString() {

    46             return "TestObject";

    47         }

    48     }

    49 

    50     ;

    51 

    52     private static TestObject str = new TestObject();

    53     private static final WeakReference ref = new WeakReference(str);

    54 

    55     private TestObject obj;

    56 

    57     public static void main(String[] args) throws Exception {

    58         Class c = Test7190310_unsafe.class.getClassLoader().loadClass("jdk.internal.misc.Unsafe");

    59         Field f = c.getDeclaredField("theUnsafe");

    60         f.setAccessible(true);

    61         Unsafe unsafe = (Unsafe) f.get(c);

    62 

    63         f = Reference.class.getDeclaredField("referent");

    64         f.setAccessible(true);

    65         long referent_offset = unsafe.objectFieldOffset(f);

    66 

    67         Test7190310_unsafe t = new Test7190310_unsafe();

    68         TestObject o = new TestObject();

    69         t.obj = o;

    70 

    71         // Warmup (compile methods)

    72         System.err.println("Warmup");

    73         Object obj = null;

    74         for (int i = 0; i < 11000; i++) {

    75             obj = getRef0(ref);

    76         }

    77         for (int i = 0; i < 11000; i++) {

    78             obj = getRef1(unsafe, ref, referent_offset);

    79         }

    80         for (int i = 0; i < 11000; i++) {

    81             obj = getRef2(unsafe, ref, referent_offset);

    82         }

    83         for (int i = 0; i < 11000; i++) {

    84             obj = getRef3(unsafe, ref, referent_offset);

    85         }

    86         for (int i = 0; i < 11000; i++) {

    87             obj = getRef4(unsafe, t, referent_offset);

    88         }

    89 

    90         // Access verification

    91         System.err.println("Verification");

    92         if (!verifyGet(referent_offset, unsafe)) {

    93             System.exit(97);

    94         }

    95 

    96         obj = getRef3(unsafe, t, referent_offset);

    97         if (obj != o) {

    98             System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + o);

    99             System.exit(97);

   100         }

   101         obj = getRef4(unsafe, t, referent_offset);

   102         if (obj != o) {

   103             System.out.println("FAILED: unsafe.getObject(Test7190310, " + referent_offset + ") " + obj + " != " + o);

   104             System.exit(97);

   105         }

   106     }

   107 

   108     static boolean verifyGet(long referent_offset, Unsafe unsafe) throws Exception {

   109         // Access verification

   110         System.out.println("referent: " + str);

   111         Object obj = getRef0(ref);

   112         if (obj != str) {

   113             System.out.println("FAILED: weakRef.get() " + obj + " != " + str);

   114             return false;

   115         }

   116         obj = getRef1(unsafe, ref, referent_offset);

   117         if (obj != str) {

   118             System.out.println("FAILED: unsafe.getObject(weakRef, " + referent_offset + ") " + obj + " != " + str);

   119             return false;

   120         }

   121         obj = getRef2(unsafe, ref, referent_offset);

   122         if (obj != str) {

   123             System.out.println("FAILED: unsafe.getObject(abstRef, " + referent_offset + ") " + obj + " != " + str);

   124             return false;

   125         }

   126         obj = getRef3(unsafe, ref, referent_offset);

   127         if (obj != str) {

   128             System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + str);

   129             return false;

   130         }

   131         return true;

   132     }

   133 

   134     static Object getRef0(WeakReference ref) throws Exception {

   135         return ref.get();

   136     }

   137 

   138     static Object getRef1(Unsafe unsafe, WeakReference ref, long referent_offset) throws Exception {

   139         return unsafe.getObject(ref, referent_offset);

   140     }

   141 

   142     static Object getRef2(Unsafe unsafe, Reference ref, long referent_offset) throws Exception {

   143         return unsafe.getObject(ref, referent_offset);

   144     }

   145 

   146     static Object getRef3(Unsafe unsafe, Object ref, long referent_offset) throws Exception {

   147         return unsafe.getObject(ref, referent_offset);

   148     }

   149 

   150     static Object getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset) throws Exception {

   151         return unsafe.getObject(ref, referent_offset);

   152     }

   153 }

   154