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