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
26 import java.lang.reflect.Method;
27 import java.net.URL;
28 import java.net.URLClassLoader;
29
30 /*
31 * @test MethodUnloadingTest
32 * @bug 8029443
33 * @summary "Tests the unloading of methods to to class unloading"
34 * @modules java.base/jdk.internal.misc
35 * @library /testlibrary /test/lib
36 * @build TestMethodUnloading
37 * @build WorkerClass
38 * @run main ClassFileInstaller sun.hotspot.WhiteBox
39 * sun.hotspot.WhiteBox$WhiteBoxPermission
40 * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:-BackgroundCompilation -XX:-UseCompressedOops -XX:CompileOnly=TestMethodUnloading::doWork TestMethodUnloading
41 */
42 public class TestMethodUnloading {
43 private static final String workerClassName = "WorkerClass";
44 private static int work = -1;
45
46 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
47 private static int COMP_LEVEL_SIMPLE = 1;
48 private static int COMP_LEVEL_FULL_OPTIMIZATION = 4;
49
50 /**
51 * Does some work by either using the workerClass or locally producing values.
52 * @param workerClass Class performing some work (will be unloaded)
53 * @param useWorker If true the workerClass is used
54 */
55 static private void doWork(Class<?> workerClass, boolean useWorker) throws InstantiationException, IllegalAccessException {
56 if (useWorker) {
57 // Create a new instance
58 Object worker = workerClass.newInstance();
59 // We would like to call a method of WorkerClass here but we cannot cast to WorkerClass
60 // because the class was loaded by a different class loader. One solution would be to use
61 // reflection but since we want C2 to implement the call as an optimized IC we call
62 // Object::hashCode() here which actually calls WorkerClass::hashCode().
63 // C2 will then implement this call as an optimized IC that points to a to-interpreter stub
64 // referencing the Method* for WorkerClass::hashCode().
65 work = worker.hashCode();
66 if (work != 42) {
67 new RuntimeException("Work not done");
68 }
69 } else {
70 // Do some important work here
71 work = 1;
72 }
73 }
74
75 /**
76 * Makes sure that method is compiled by forcing compilation if not yet compiled.
77 * @param m Method to be checked
78 */
79 static private void makeSureIsCompiled(Method m) {
80 // Make sure background compilation is disabled
81 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) {
82 throw new RuntimeException("Background compilation enabled");
83 }
84
85 // Check if already compiled
86 if (!WHITE_BOX.isMethodCompiled(m)) {
87 // If not, try to compile it with C2
88 if(!WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION)) {
89 // C2 compiler not available, try to compile with C1
90 WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_SIMPLE);
91 }
92 // Because background compilation is disabled, method should now be compiled
93 if(!WHITE_BOX.isMethodCompiled(m)) {
94 throw new RuntimeException(m + " not compiled");
95 }
96 }
97 }
98
99 /**
100 * This test creates stale Method* metadata in a to-interpreter stub of an optimized IC.
101 *
102 * The following steps are performed:
103 * (1) A workerClass is loaded by a custom class loader
104 * (2) The method doWork that calls a method of the workerClass is compiled. The call
105 * is implemented as an optimized IC calling a to-interpreted stub. The to-interpreter
106 * stub contains a Method* to a workerClass method.
107 * (3) Unloading of the workerClass is enforced. The to-interpreter stub now contains a dead Method*.
108 * (4) Depending on the implementation of the IC, the compiled version of doWork should still be
109 * valid. We call it again without using the workerClass.
110 */
111 static public void main(String[] args) throws Exception {
112 // (1) Create a custom class loader with no parent class loader
113 URL url = TestMethodUnloading.class.getProtectionDomain().getCodeSource().getLocation();
114 URLClassLoader loader = new URLClassLoader(new URL[] {url}, null);
115
116 // Load worker class with custom class loader
117 Class<?> workerClass = Class.forName(workerClassName, true, loader);
118
119 // (2) Make sure all paths of doWork are profiled and compiled
120 for (int i = 0; i < 100000; ++i) {
121 doWork(workerClass, true);
122 doWork(workerClass, false);
123 }
124
125 // Make sure doWork is compiled now
126 Method doWork = TestMethodUnloading.class.getDeclaredMethod("doWork", Class.class, boolean.class);
127 makeSureIsCompiled(doWork);
128
129 // (3) Throw away class loader and reference to workerClass to allow unloading
130 loader.close();
131 loader = null;
132 workerClass = null;
133
134 // Force garbage collection to trigger unloading of workerClass
135 // Dead reference to WorkerClass::hashCode triggers JDK-8029443
136 WHITE_BOX.fullGC();
137
138 // (4) Depending on the implementation of the IC, the compiled version of doWork
139 // may still be valid here. Execute it without a workerClass.
140 doWork(null, false);
141 if (work != 1) {
142 throw new RuntimeException("Work not done");
143 }
144
145 doWork(Object.class, false);
146 }
147 }