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comparison test/compiler/7190310/Test7190310_unsafe.java @ 6615:09aad8452938

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7190310: Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops Summary: In C2 add software membar after load from Reference.referent field to prevent commoning of loads across safepoint since GC can change its value. In C1 always generate Reference.get() intrinsic. Reviewed-by: roland, twisti, dholmes, johnc
author kvn
date Mon, 20 Aug 2012 09:58:58 -0700
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6614:006050192a5a 6615:09aad8452938
1 /*
2 * Copyright (c) 2012, 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 /*
26 * @test
27 * @bug 7190310
28 * @summary Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops
29 * @run main/othervm -Xbatch Test7190310_unsafe
30 */
31
32 import java.lang.ref.*;
33 import java.lang.reflect.*;
34 import sun.misc.Unsafe;
35
36 public class Test7190310_unsafe {
37
38 static class TestObject {
39 public String toString() {
40 return "TestObject";
41 }
42 };
43
44 private static TestObject str = new TestObject();
45 private static final WeakReference ref = new WeakReference(str);
46
47 private TestObject obj;
48
49 public static void main(String[] args) throws Exception {
50 Class c = Test7190310_unsafe.class.getClassLoader().loadClass("sun.misc.Unsafe");
51 Field f = c.getDeclaredField("theUnsafe");
52 f.setAccessible(true);
53 Unsafe unsafe = (Unsafe)f.get(c);
54
55 f = Reference.class.getDeclaredField("referent");
56 f.setAccessible(true);
57 long referent_offset = unsafe.objectFieldOffset(f);
58
59 Test7190310_unsafe t = new Test7190310_unsafe();
60 TestObject o = new TestObject();
61 t.obj = o;
62
63 // Warmup (compile methods)
64 System.err.println("Warmup");
65 Object obj = null;
66 for (int i = 0; i < 11000; i++) {
67 obj = getRef0(ref);
68 }
69 for (int i = 0; i < 11000; i++) {
70 obj = getRef1(unsafe, ref, referent_offset);
71 }
72 for (int i = 0; i < 11000; i++) {
73 obj = getRef2(unsafe, ref, referent_offset);
74 }
75 for (int i = 0; i < 11000; i++) {
76 obj = getRef3(unsafe, ref, referent_offset);
77 }
78 for (int i = 0; i < 11000; i++) {
79 obj = getRef4(unsafe, t, referent_offset);
80 }
81
82 // Access verification
83 System.err.println("Verification");
84 if (!verifyGet(referent_offset, unsafe)) {
85 System.exit(97);
86 }
87
88 obj = getRef3(unsafe, t, referent_offset);
89 if (obj != o) {
90 System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + o);
91 System.exit(97);
92 }
93 obj = getRef4(unsafe, t, referent_offset);
94 if (obj != o) {
95 System.out.println("FAILED: unsafe.getObject(Test7190310, " + referent_offset + ") " + obj + " != " + o);
96 System.exit(97);
97 }
98 }
99
100 static boolean verifyGet(long referent_offset, Unsafe unsafe) throws Exception {
101 // Access verification
102 System.out.println("referent: " + str);
103 Object obj = getRef0(ref);
104 if (obj != str) {
105 System.out.println("FAILED: weakRef.get() " + obj + " != " + str);
106 return false;
107 }
108 obj = getRef1(unsafe, ref, referent_offset);
109 if (obj != str) {
110 System.out.println("FAILED: unsafe.getObject(weakRef, " + referent_offset + ") " + obj + " != " + str);
111 return false;
112 }
113 obj = getRef2(unsafe, ref, referent_offset);
114 if (obj != str) {
115 System.out.println("FAILED: unsafe.getObject(abstRef, " + referent_offset + ") " + obj + " != " + str);
116 return false;
117 }
118 obj = getRef3(unsafe, ref, referent_offset);
119 if (obj != str) {
120 System.out.println("FAILED: unsafe.getObject(Object, " + referent_offset + ") " + obj + " != " + str);
121 return false;
122 }
123 return true;
124 }
125
126 static Object getRef0(WeakReference ref) throws Exception {
127 return ref.get();
128 }
129 static Object getRef1(Unsafe unsafe, WeakReference ref, long referent_offset) throws Exception {
130 return unsafe.getObject(ref, referent_offset);
131 }
132 static Object getRef2(Unsafe unsafe, Reference ref, long referent_offset) throws Exception {
133 return unsafe.getObject(ref, referent_offset);
134 }
135 static Object getRef3(Unsafe unsafe, Object ref, long referent_offset) throws Exception {
136 return unsafe.getObject(ref, referent_offset);
137 }
138 static Object getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset) throws Exception {
139 return unsafe.getObject(ref, referent_offset);
140 }
141 }
142