1 /* 2 * Copyright (c) 2014, 2016, 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 /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 import compiler.whitebox.CompilerWhiteBoxTest; 46 47 public class TestAnonymousClassUnloading { 48 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox(); 49 private static final Unsafe UNSAFE = Unsafe.getUnsafe(); 50 51 /** 52 * We override hashCode here to be able to access this implementation 53 * via an Object reference (we cannot cast to TestAnonymousClassUnloading). 54 */ 55 @Override 56 public int hashCode() { 57 return 42; 58 } 59 60 /** 61 * Does some work by using the anonymousClass. 62 * @param anonymousClass Class performing some work (will be unloaded) 63 */ 64 static private void doWork(Class<?> anonymousClass) throws InstantiationException, IllegalAccessException { 65 // Create a new instance 66 Object anon = anonymousClass.newInstance(); 67 // We would like to call a method of anonymousClass here but we cannot cast because the class 68 // was loaded by a different class loader. One solution would be to use reflection but since 69 // we want C2 to implement the call as an IC we call Object::hashCode() here which actually 70 // calls anonymousClass::hashCode(). C2 will then implement this call as an IC. 71 if (anon.hashCode() != 42) { 72 new RuntimeException("Work not done"); 73 } 74 } 75 76 /** 77 * Makes sure that method is compiled by forcing compilation if not yet compiled. 78 * @param m Method to be checked 79 */ 80 static private void makeSureIsCompiled(Method m) { 81 // Make sure background compilation is disabled 82 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) { 83 throw new RuntimeException("Background compilation enabled"); 84 } 85 86 // Check if already compiled 87 if (!WHITE_BOX.isMethodCompiled(m)) { 88 // If not, try to compile it with C2 89 if(!WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_FULL_OPTIMIZATION)) { 90 // C2 compiler not available, try to compile with C1 91 WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_SIMPLE); 92 } 93 // Because background compilation is disabled, method should now be compiled 94 if(!WHITE_BOX.isMethodCompiled(m)) { 95 throw new RuntimeException(m + " not compiled"); 96 } 97 } 98 } 99 100 /** 101 * This test creates stale Klass* metadata referenced by a compiled IC. 102 * 103 * The following steps are performed: 104 * (1) An anonymous version of TestAnonymousClassUnloading is loaded by a custom class loader 105 * (2) The method doWork that calls a method of the anonymous class is compiled. The call 106 * is implemented as an IC referencing Klass* metadata of the anonymous class. 107 * (3) Unloading of the anonymous class is enforced. The IC now references dead metadata. 108 */ 109 static public void main(String[] args) throws Exception { 110 // (1) Load an anonymous version of this class using the corresponding Unsafe method 111 String rn = TestAnonymousClassUnloading.class.getSimpleName() + ".class"; 112 URL classUrl = TestAnonymousClassUnloading.class.getResource(rn); 113 URLConnection connection = classUrl.openConnection(); 114 115 int length = connection.getContentLength(); 116 byte[] classBytes = connection.getInputStream().readAllBytes(); 117 if (length != -1 && classBytes.length != length) { 118 throw new IOException("Expected:" + length + ", actual: " + classBytes.length); 119 } 120 121 Class<?> anonymousClass = UNSAFE.defineAnonymousClass(TestAnonymousClassUnloading.class, classBytes, null); 122 123 // (2) Make sure all paths of doWork are profiled and compiled 124 for (int i = 0; i < 100000; ++i) { 125 doWork(anonymousClass); 126 } 127 128 // Make sure doWork is compiled now 129 Method doWork = TestAnonymousClassUnloading.class.getDeclaredMethod("doWork", Class.class); 130 makeSureIsCompiled(doWork); 131 132 // (3) Throw away reference to anonymousClass to allow unloading 133 anonymousClass = null; 134 135 // Force garbage collection to trigger unloading of anonymousClass 136 // Dead metadata reference to anonymousClass triggers JDK-8054402 137 WHITE_BOX.fullGC(); 138 } 139 }