1 /* 2 * Copyright (c) 2014, 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 * @bug 8054402 27 * @summary "Tests unloading of anonymous classes." 28 * @library /test/lib / 29 * @modules java.base/jdk.internal.misc 30 * @build sun.hotspot.WhiteBox 31 * @run driver ClassFileInstaller sun.hotspot.WhiteBox 32 * 33 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI 34 * -XX:-BackgroundCompilation 35 * compiler.classUnloading.anonymousClass.TestAnonymousClassUnloading 36 */ 37 38 package compiler.classUnloading.anonymousClass; 39 40 import jdk.internal.misc.Unsafe; 41 import sun.hotspot.WhiteBox; 42 43 import java.io.IOException; 44 import java.lang.reflect.Method; 45 import java.net.URL; 46 import java.net.URLConnection; 47 import compiler.whitebox.CompilerWhiteBoxTest; 48 49 public class TestAnonymousClassUnloading { 50 private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox(); 51 private static final Unsafe UNSAFE = Unsafe.getUnsafe(); 52 53 /** 54 * We override hashCode here to be able to access this implementation 55 * via an Object reference (we cannot cast to TestAnonymousClassUnloading). 56 */ 57 @Override hashCode()58 public int hashCode() { 59 return 42; 60 } 61 62 /** 63 * Does some work by using the anonymousClass. 64 * @param anonymousClass Class performing some work (will be unloaded) 65 */ doWork(Class<?> anonymousClass)66 static private void doWork(Class<?> anonymousClass) throws InstantiationException, IllegalAccessException { 67 // Create a new instance 68 Object anon = anonymousClass.newInstance(); 69 // We would like to call a method of anonymousClass here but we cannot cast because the class 70 // was loaded by a different class loader. One solution would be to use reflection but since 71 // we want C2 to implement the call as an IC we call Object::hashCode() here which actually 72 // calls anonymousClass::hashCode(). C2 will then implement this call as an IC. 73 if (anon.hashCode() != 42) { 74 new RuntimeException("Work not done"); 75 } 76 } 77 78 /** 79 * Makes sure that method is compiled by forcing compilation if not yet compiled. 80 * @param m Method to be checked 81 */ makeSureIsCompiled(Method m)82 static private void makeSureIsCompiled(Method m) { 83 // Make sure background compilation is disabled 84 if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) { 85 throw new RuntimeException("Background compilation enabled"); 86 } 87 88 // Check if already compiled 89 if (!WHITE_BOX.isMethodCompiled(m)) { 90 // If not, try to compile it with C2 91 if(!WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_FULL_OPTIMIZATION)) { 92 // C2 compiler not available, try to compile with C1 93 WHITE_BOX.enqueueMethodForCompilation(m, CompilerWhiteBoxTest.COMP_LEVEL_SIMPLE); 94 } 95 // Because background compilation is disabled, method should now be compiled 96 if(!WHITE_BOX.isMethodCompiled(m)) { 97 throw new RuntimeException(m + " not compiled"); 98 } 99 } 100 } 101 102 /** 103 * This test creates stale Klass* metadata referenced by a compiled IC. 104 * 105 * The following steps are performed: 106 * (1) An anonymous version of TestAnonymousClassUnloading is loaded by a custom class loader 107 * (2) The method doWork that calls a method of the anonymous class is compiled. The call 108 * is implemented as an IC referencing Klass* metadata of the anonymous class. 109 * (3) Unloading of the anonymous class is enforced. The IC now references dead metadata. 110 */ main(String[] args)111 static public void main(String[] args) throws Exception { 112 // (1) Load an anonymous version of this class using the corresponding Unsafe method 113 String rn = TestAnonymousClassUnloading.class.getSimpleName() + ".class"; 114 URL classUrl = TestAnonymousClassUnloading.class.getResource(rn); 115 URLConnection connection = classUrl.openConnection(); 116 117 int length = connection.getContentLength(); 118 byte[] classBytes = connection.getInputStream().readAllBytes(); 119 if (length != -1 && classBytes.length != length) { 120 throw new IOException("Expected:" + length + ", actual: " + classBytes.length); 121 } 122 123 Class<?> anonymousClass = UNSAFE.defineAnonymousClass(TestAnonymousClassUnloading.class, classBytes, null); 124 125 // (2) Make sure all paths of doWork are profiled and compiled 126 for (int i = 0; i < 100000; ++i) { 127 doWork(anonymousClass); 128 } 129 130 // Make sure doWork is compiled now 131 Method doWork = TestAnonymousClassUnloading.class.getDeclaredMethod("doWork", Class.class); 132 makeSureIsCompiled(doWork); 133 134 // (3) Throw away reference to anonymousClass to allow unloading 135 anonymousClass = null; 136 137 // Force garbage collection to trigger unloading of anonymousClass 138 // Dead metadata reference to anonymousClass triggers JDK-8054402 139 WHITE_BOX.fullGC(); 140 } 141 } 142