TestMethodUnloading.java revision 6865:d5d005f1d973 
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
24import sun.hotspot.WhiteBox;
25
26import java.lang.reflect.Method;
27import java.net.URL;
28import java.net.URLClassLoader;
29
30/*
31 * @test MethodUnloadingTest
32 * @bug 8029443
33 * @summary "Tests the unloading of methods to to class unloading"
34 * @library /testlibrary /testlibrary/whitebox
35 * @build TestMethodUnloading
36 * @build WorkerClass
37 * @run main ClassFileInstaller sun.hotspot.WhiteBox
38 *                              sun.hotspot.WhiteBox$WhiteBoxPermission
39 * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:-BackgroundCompilation -XX:-UseCompressedOops -XX:+UseParallelGC -XX:CompileOnly=TestMethodUnloading::doWork TestMethodUnloading
40 */
41public class TestMethodUnloading {
42    private static final String workerClassName = "WorkerClass";
43    private static int work = -1;
44
45    private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
46    private static int COMP_LEVEL_SIMPLE = 1;
47    private static int COMP_LEVEL_FULL_OPTIMIZATION = 4;
48
49    /**
50     * Does some work by either using the workerClass or locally producing values.
51     * @param workerClass Class performing some work (will be unloaded)
52     * @param useWorker If true the workerClass is used
53     */
54    static private void doWork(Class<?> workerClass, boolean useWorker) throws InstantiationException, IllegalAccessException {
55        if (useWorker) {
56            // Create a new instance
57            Object worker = workerClass.newInstance();
58            // We would like to call a method of WorkerClass here but we cannot cast to WorkerClass
59            // because the class was loaded by a different class loader. One solution would be to use
60            // reflection but since we want C2 to implement the call as an optimized IC we call
61            // Object::hashCode() here which actually calls WorkerClass::hashCode().
62            // C2 will then implement this call as an optimized IC that points to a to-interpreter stub
63            // referencing the Method* for WorkerClass::hashCode().
64            work = worker.hashCode();
65            if (work != 42) {
66                new RuntimeException("Work not done");
67            }
68        } else {
69            // Do some important work here
70            work = 1;
71        }
72    }
73
74    /**
75     * Makes sure that method is compiled by forcing compilation if not yet compiled.
76     * @param m Method to be checked
77     */
78    static private void makeSureIsCompiled(Method m) {
79        // Make sure background compilation is disabled
80        if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) {
81            throw new RuntimeException("Background compilation enabled");
82        }
83
84        // Check if already compiled
85        if (!WHITE_BOX.isMethodCompiled(m)) {
86            // If not, try to compile it with C2
87            if(!WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION)) {
88                // C2 compiler not available, try to compile with C1
89                WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_SIMPLE);
90            }
91            // Because background compilation is disabled, method should now be compiled
92            if(!WHITE_BOX.isMethodCompiled(m)) {
93                throw new RuntimeException(m + " not compiled");
94            }
95        }
96    }
97
98    /**
99     * This test creates stale Method* metadata in a to-interpreter stub of an optimized IC.
100     *
101     * The following steps are performed:
102     * (1) A workerClass is loaded by a custom class loader
103     * (2) The method doWork that calls a method of the workerClass is compiled. The call
104     *     is implemented as an optimized IC calling a to-interpreted stub. The to-interpreter
105     *     stub contains a Method* to a workerClass method.
106     * (3) Unloading of the workerClass is enforced. The to-interpreter stub now contains a dead Method*.
107     * (4) Depending on the implementation of the IC, the compiled version of doWork should still be
108     *     valid. We call it again without using the workerClass.
109     */
110    static public void main(String[] args) throws Exception {
111        // (1) Create a custom class loader with no parent class loader
112        URL url = TestMethodUnloading.class.getProtectionDomain().getCodeSource().getLocation();
113        URLClassLoader loader = new URLClassLoader(new URL[] {url}, null);
114
115        // Load worker class with custom class loader
116        Class<?> workerClass = Class.forName(workerClassName, true, loader);
117
118        // (2) Make sure all paths of doWork are profiled and compiled
119        for (int i = 0; i < 100000; ++i) {
120            doWork(workerClass, true);
121            doWork(workerClass, false);
122        }
123
124        // Make sure doWork is compiled now
125        Method doWork = TestMethodUnloading.class.getDeclaredMethod("doWork", Class.class, boolean.class);
126        makeSureIsCompiled(doWork);
127
128        // (3) Throw away class loader and reference to workerClass to allow unloading
129        loader.close();
130        loader = null;
131        workerClass = null;
132
133        // Force garbage collection to trigger unloading of workerClass
134        // Dead reference to WorkerClass::hashCode triggers JDK-8029443
135        WHITE_BOX.fullGC();
136
137        // (4) Depending on the implementation of the IC, the compiled version of doWork
138        // may still be valid here. Execute it without a workerClass.
139        doWork(null, false);
140        if (work != 1) {
141            throw new RuntimeException("Work not done");
142        }
143
144        doWork(Object.class, false);
145    }
146}
147