1 /*
2 * Copyright (c) 2014, 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 TestAnonymousClassUnloading
26 * @bug 8054402
27 * @summary "Tests unloading of anonymous classes."
28 * @library /testlibrary /test/lib /
29 * @modules java.base/jdk.internal.misc
30 *
31 * @run main/othervm/bootclasspath -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
32 * -XX:-BackgroundCompilation
33 * compiler.classUnloading.anonymousClass.TestAnonymousClassUnloading
34 */
35
36 package compiler.classUnloading.anonymousClass;
37
38 import jdk.internal.misc.Unsafe;
39 import sun.hotspot.WhiteBox;
40
41 import java.io.IOException;
42 import java.lang.reflect.Method;
43 import java.net.URL;
44 import java.net.URLConnection;
45
46 public class TestAnonymousClassUnloading {
47 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
48 private static final Unsafe UNSAFE = Unsafe.getUnsafe();
49 private static int COMP_LEVEL_SIMPLE = 1;
50 private static int COMP_LEVEL_FULL_OPTIMIZATION = 4;
51
52 /**
53 * We override hashCode here to be able to access this implementation
54 * via an Object reference (we cannot cast to TestAnonymousClassUnloading).
55 */
56 @Override
57 public int hashCode() {
58 return 42;
59 }
60
61 /**
62 * Does some work by using the anonymousClass.
63 * @param anonymousClass Class performing some work (will be unloaded)
64 */
65 static private void doWork(Class<?> anonymousClass) throws InstantiationException, IllegalAccessException {
66 // Create a new instance
67 Object anon = anonymousClass.newInstance();
68 // We would like to call a method of anonymousClass here but we cannot cast because the class
69 // was loaded by a different class loader. One solution would be to use reflection but since
70 // we want C2 to implement the call as an IC we call Object::hashCode() here which actually
71 // calls anonymousClass::hashCode(). C2 will then implement this call as an IC.
72 if (anon.hashCode() != 42) {
73 new RuntimeException("Work not done");
74 }
75 }
76
77 /**
78 * Makes sure that method is compiled by forcing compilation if not yet compiled.
79 * @param m Method to be checked
80 */
81 static private void makeSureIsCompiled(Method m) {
82 // Make sure background compilation is disabled
83 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) {
84 throw new RuntimeException("Background compilation enabled");
85 }
86
87 // Check if already compiled
88 if (!WHITE_BOX.isMethodCompiled(m)) {
89 // If not, try to compile it with C2
90 if(!WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION)) {
91 // C2 compiler not available, try to compile with C1
92 WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_SIMPLE);
93 }
94 // Because background compilation is disabled, method should now be compiled
95 if(!WHITE_BOX.isMethodCompiled(m)) {
96 throw new RuntimeException(m + " not compiled");
97 }
98 }
99 }
100
101 /**
102 * This test creates stale Klass* metadata referenced by a compiled IC.
103 *
104 * The following steps are performed:
105 * (1) An anonymous version of TestAnonymousClassUnloading is loaded by a custom class loader
106 * (2) The method doWork that calls a method of the anonymous class is compiled. The call
107 * is implemented as an IC referencing Klass* metadata of the anonymous class.
108 * (3) Unloading of the anonymous class is enforced. The IC now references dead metadata.
109 */
110 static public void main(String[] args) throws Exception {
111 // (1) Load an anonymous version of this class using the corresponding Unsafe method
112 URL classUrl = TestAnonymousClassUnloading.class.getResource(
113 TestAnonymousClassUnloading.class.getName().replace('.', '/') + ".class");
114 URLConnection connection = classUrl.openConnection();
115
116 int length = connection.getContentLength();
117 byte[] classBytes = connection.getInputStream().readAllBytes();
118 if (length != -1 && classBytes.length != length) {
119 throw new IOException("Expected:" + length + ", actual: " + classBytes.length);
120 }
121
122 Class<?> anonymousClass = UNSAFE.defineAnonymousClass(TestAnonymousClassUnloading.class, classBytes, null);
123
124 // (2) Make sure all paths of doWork are profiled and compiled
125 for (int i = 0; i < 100000; ++i) {
126 doWork(anonymousClass);
127 }
128
129 // Make sure doWork is compiled now
130 Method doWork = TestAnonymousClassUnloading.class.getDeclaredMethod("doWork", Class.class);
131 makeSureIsCompiled(doWork);
132
133 // (3) Throw away reference to anonymousClass to allow unloading
134 anonymousClass = null;
135
136 // Force garbage collection to trigger unloading of anonymousClass
137 // Dead metadata reference to anonymousClass triggers JDK-8054402
138 WHITE_BOX.fullGC();
139 }
140 }