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
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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
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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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
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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 {
toString()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 
main(String[] args)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.getReference(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.getReference(Test7190310, " + referent_offset + ") " + obj + " != " + o);
104             System.exit(97);
105         }
106     }
107 
verifyGet(long referent_offset, Unsafe unsafe)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.getReference(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.getReference(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.getReference(Object, " + referent_offset + ") " + obj + " != " + str);
129             return false;
130         }
131         return true;
132     }
133 
getRef0(WeakReference ref)134     static Object getRef0(WeakReference ref) throws Exception {
135         return ref.get();
136     }
137 
getRef1(Unsafe unsafe, WeakReference ref, long referent_offset)138     static Object getRef1(Unsafe unsafe, WeakReference ref, long referent_offset) throws Exception {
139         return unsafe.getReference(ref, referent_offset);
140     }
141 
getRef2(Unsafe unsafe, Reference ref, long referent_offset)142     static Object getRef2(Unsafe unsafe, Reference ref, long referent_offset) throws Exception {
143         return unsafe.getReference(ref, referent_offset);
144     }
145 
getRef3(Unsafe unsafe, Object ref, long referent_offset)146     static Object getRef3(Unsafe unsafe, Object ref, long referent_offset) throws Exception {
147         return unsafe.getReference(ref, referent_offset);
148     }
149 
getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset)150     static Object getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset) throws Exception {
151         return unsafe.getReference(ref, referent_offset);
152     }
153 }
154 
155