1 /*
2 * Copyright (c) 2014, 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 import sun.hotspot.WhiteBox;
25 import sun.misc.Unsafe;
26 import sun.misc.IOUtils;
27
28 import java.lang.reflect.Method;
29 import java.net.URL;
30 import java.net.URLConnection;
31
32 /*
33 * @test TestAnonymousClassUnloading
34 * @bug 8054402
35 * @summary "Tests unloading of anonymous classes."
36 * @library /testlibrary /testlibrary/whitebox
37 * @compile TestAnonymousClassUnloading.java
38 * @run main ClassFileInstaller TestAnonymousClassUnloading sun.hotspot.WhiteBox
39 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:-BackgroundCompilation TestAnonymousClassUnloading
40 */
41 public class TestAnonymousClassUnloading {
42 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
43 private static final Unsafe UNSAFE = Unsafe.getUnsafe();
44 private static int COMP_LEVEL_SIMPLE = 1;
45 private static int COMP_LEVEL_FULL_OPTIMIZATION = 4;
46
47 /**
48 * We override hashCode here to be able to access this implementation
49 * via an Object reference (we cannot cast to TestAnonymousClassUnloading).
50 */
51 @Override
52 public int hashCode() {
53 return 42;
54 }
55
56 /**
57 * Does some work by using the anonymousClass.
58 * @param anonymousClass Class performing some work (will be unloaded)
59 */
60 static private void doWork(Class<?> anonymousClass) throws InstantiationException, IllegalAccessException {
61 // Create a new instance
62 Object anon = anonymousClass.newInstance();
63 // We would like to call a method of anonymousClass here but we cannot cast because the class
64 // was loaded by a different class loader. One solution would be to use reflection but since
65 // we want C2 to implement the call as an IC we call Object::hashCode() here which actually
66 // calls anonymousClass::hashCode(). C2 will then implement this call as an IC.
67 if (anon.hashCode() != 42) {
68 new RuntimeException("Work not done");
69 }
70 }
71
72 /**
73 * Makes sure that method is compiled by forcing compilation if not yet compiled.
74 * @param m Method to be checked
75 */
76 static private void makeSureIsCompiled(Method m) {
77 // Make sure background compilation is disabled
78 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) {
79 throw new RuntimeException("Background compilation enabled");
80 }
81
82 // Check if already compiled
83 if (!WHITE_BOX.isMethodCompiled(m)) {
84 // If not, try to compile it with C2
85 if(!WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION)) {
86 // C2 compiler not available, try to compile with C1
87 WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_SIMPLE);
88 }
89 // Because background compilation is disabled, method should now be compiled
90 if(!WHITE_BOX.isMethodCompiled(m)) {
91 throw new RuntimeException(m + " not compiled");
92 }
93 }
94 }
95
96 /**
97 * This test creates stale Klass* metadata referenced by a compiled IC.
98 *
99 * The following steps are performed:
100 * (1) An anonymous version of TestAnonymousClassUnloading is loaded by a custom class loader
101 * (2) The method doWork that calls a method of the anonymous class is compiled. The call
102 * is implemented as an IC referencing Klass* metadata of the anonymous class.
103 * (3) Unloading of the anonymous class is enforced. The IC now references dead metadata.
104 */
105 static public void main(String[] args) throws Exception {
106 // (1) Load an anonymous version of this class using the corresponding Unsafe method
107 URL classUrl = TestAnonymousClassUnloading.class.getResource("TestAnonymousClassUnloading.class");
108 URLConnection connection = classUrl.openConnection();
109 byte[] classBytes = IOUtils.readFully(connection.getInputStream(), connection.getContentLength(), true);
110 Class<?> anonymousClass = UNSAFE.defineAnonymousClass(TestAnonymousClassUnloading.class, classBytes, null);
111
112 // (2) Make sure all paths of doWork are profiled and compiled
113 for (int i = 0; i < 100000; ++i) {
114 doWork(anonymousClass);
115 }
116
117 // Make sure doWork is compiled now
118 Method doWork = TestAnonymousClassUnloading.class.getDeclaredMethod("doWork", Class.class);
119 makeSureIsCompiled(doWork);
120
121 // (3) Throw away reference to anonymousClass to allow unloading
122 anonymousClass = null;
123
124 // Force garbage collection to trigger unloading of anonymousClass
125 // Dead metadata reference to anonymousClass triggers JDK-8054402
126 WHITE_BOX.fullGC();
127 }
128 }