1 /*
2 * Copyright (c) 2020, 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
26 * @summary Test unloading of hidden classes.
27 * @library /test/lib /
28 * @build sun.hotspot.WhiteBox
29 * @run driver ClassFileInstaller sun.hotspot.WhiteBox
30 * sun.hotspot.WhiteBox$WhiteBoxPermission
31 *
32 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
33 * -XX:-BackgroundCompilation
34 * compiler.classUnloading.hiddenClass.TestHiddenClassUnloading
35 */
36
37 package compiler.classUnloading.hiddenClass;
38
39 import sun.hotspot.WhiteBox;
40
41 import java.io.IOException;
42 import java.lang.invoke.MethodHandles;
43 import java.lang.invoke.MethodHandles.Lookup;
44 import static java.lang.invoke.MethodHandles.Lookup.ClassOption.*;
45 import java.lang.reflect.Method;
46 import java.net.URL;
47 import java.net.URLConnection;
48 import compiler.whitebox.CompilerWhiteBoxTest;
49
50 // This is based on test compiler/classUnloading/anonymousClass/TestAnonymousClassUnloading.java
51 public class TestHiddenClassUnloading {
52 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
53
54 /**
55 * We override hashCode here to be able to access this implementation
56 * via an Object reference (we cannot cast to TestHiddenClassUnloading).
57 */
58 @Override
59 public int hashCode() {
60 return 42;
61 }
62
63 /**
64 * Does some work by using the hiddenClass.
65 * @param hiddenClass Class performing some work (will be unloaded)
66 */
67 static private void doWork(Class<?> hiddenClass) throws InstantiationException, IllegalAccessException {
68 // Create a new instance
69 Object anon = hiddenClass.newInstance();
70 // We would like to call a method of hiddenClass here but we cannot cast because the class
71 // was loaded by a different class loader. One solution would be to use reflection but since
72 // we want C2 to implement the call as an IC we call Object::hashCode() here which actually
73 // calls hiddenClass::hashCode(). C2 will then implement this call as an IC.
74 if (anon.hashCode() != 42) {
75 new RuntimeException("Work not done");
76 }
77 }
78
79 /**
80 * Makes sure that method is compiled by forcing compilation if not yet compiled.
81 * @param m Method to be checked
82 */
83 static private void makeSureIsCompiled(Method m) {
84 // Make sure background compilation is disabled
85 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) {
86 throw new RuntimeException("Background compilation enabled");
87 }
88
89 // Check if already compiled
90 if (!WHITE_BOX.isMethodCompiled(m)) {
91 // If not, try to compile it with C2
92 if(!WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_FULL_OPTIMIZATION)) {
93 // C2 compiler not available, try to compile with C1
94 WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_SIMPLE);
95 }
96 // Because background compilation is disabled, method should now be compiled
97 if(!WHITE_BOX.isMethodCompiled(m)) {
98 throw new RuntimeException(m + " not compiled");
99 }
100 }
101 }
102
103 /**
104 * This test creates stale Klass* metadata referenced by a compiled IC.
105 *
106 * The following steps are performed:
107 * (1) A hidden version of TestHiddenClassUnloading is loaded by a custom class loader
108 * (2) The method doWork that calls a method of the hidden class is compiled. The call
109 * is implemented as an IC referencing Klass* metadata of the hidden class.
110 * (3) Unloading of the hidden class is enforced. The IC now references dead metadata.
111 */
112 static public void main(String[] args) throws Exception {
113 // (1) Load a hidden version of this class using method lookup.defineHiddenClass().
114 String rn = TestHiddenClassUnloading.class.getSimpleName() + ".class";
115 URL classUrl = TestHiddenClassUnloading.class.getResource(rn);
116 URLConnection connection = classUrl.openConnection();
117
118 int length = connection.getContentLength();
119 byte[] classBytes = connection.getInputStream().readAllBytes();
120 if (length != -1 && classBytes.length != length) {
121 throw new IOException("Expected:" + length + ", actual: " + classBytes.length);
122 }
123
124 Lookup lookup = MethodHandles.lookup();
125 Class<?> hiddenClass = lookup.defineHiddenClass(classBytes, true, NESTMATE, WEAK).lookupClass();
126
127 // (2) Make sure all paths of doWork are profiled and compiled
128 for (int i = 0; i < 100000; ++i) {
129 doWork(hiddenClass);
130 }
131
132 // Make sure doWork is compiled now
133 Method doWork = TestHiddenClassUnloading.class.getDeclaredMethod("doWork", Class.class);
134 makeSureIsCompiled(doWork);
135
136 // (3) Throw away reference to hiddenClass to allow unloading
137 hiddenClass = null;
138
139 // Force garbage collection to trigger unloading of hiddenClass
140 WHITE_BOX.fullGC();
141 }
142 }