# HG changeset patch # User thartmann # Date 1408947617 -7200 # Node ID c3990b8c710e4c1996b5cd579681645d9f0408c1 # Parent 7fa57b65c27f6f483a002f08eede48042028bebe 8054402: "klass->is_loader_alive(_is_alive)) failed: must be alive" for anonymous classes Summary: Because anonymous classes are not in the system dictionary, we have to set 'unloading_occurred' based on 'CLDG::do_unloading()'. Added jtreg test. Reviewed-by: kvn, coleenp diff -r 7fa57b65c27f -r c3990b8c710e src/share/vm/classfile/dictionary.cpp --- a/src/share/vm/classfile/dictionary.cpp Thu Aug 21 14:48:49 2014 -0700 +++ b/src/share/vm/classfile/dictionary.cpp Mon Aug 25 08:20:17 2014 +0200 @@ -130,15 +130,13 @@ } -bool Dictionary::do_unloading() { +void Dictionary::do_unloading() { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); - bool class_was_unloaded = false; - int index = 0; // Defined here for portability! Do not move // Remove unloadable entries and classes from system dictionary // The placeholder array has been handled in always_strong_oops_do. DictionaryEntry* probe = NULL; - for (index = 0; index < table_size(); index++) { + for (int index = 0; index < table_size(); index++) { for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) { probe = *p; Klass* e = probe->klass(); @@ -158,16 +156,8 @@ // Do we need to delete this system dictionary entry? if (loader_data->is_unloading()) { // If the loader is not live this entry should always be - // removed (will never be looked up again). Note that this is - // not the same as unloading the referred class. - if (k_def_class_loader_data == loader_data) { - // This is the defining entry, so the referred class is about - // to be unloaded. - class_was_unloaded = true; - } - // Also remove this system dictionary entry. + // removed (will never be looked up again). purge_entry = true; - } else { // The loader in this entry is alive. If the klass is dead, // (determined by checking the defining class loader) @@ -196,7 +186,6 @@ p = probe->next_addr(); } } - return class_was_unloaded; } void Dictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { diff -r 7fa57b65c27f -r c3990b8c710e src/share/vm/classfile/dictionary.hpp --- a/src/share/vm/classfile/dictionary.hpp Thu Aug 21 14:48:49 2014 -0700 +++ b/src/share/vm/classfile/dictionary.hpp Mon Aug 25 08:20:17 2014 +0200 @@ -108,9 +108,8 @@ return (loader_data->is_the_null_class_loader_data() || !ClassUnloading); } - // Unload (that is, break root links to) all unmarked classes and - // loaders. Returns "true" iff something was unloaded. - bool do_unloading(); + // Unload (that is, break root links to) all unmarked classes and loaders. + void do_unloading(); // Protection domains Klass* find(int index, unsigned int hash, Symbol* name, diff -r 7fa57b65c27f -r c3990b8c710e src/share/vm/classfile/systemDictionary.cpp --- a/src/share/vm/classfile/systemDictionary.cpp Thu Aug 21 14:48:49 2014 -0700 +++ b/src/share/vm/classfile/systemDictionary.cpp Mon Aug 25 08:20:17 2014 +0200 @@ -1662,10 +1662,9 @@ // Note: anonymous classes are not in the SD. bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { // First, mark for unload all ClassLoaderData referencing a dead class loader. - bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive); - bool unloading_occurred = false; - if (has_dead_loaders) { - unloading_occurred = dictionary()->do_unloading(); + bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive); + if (unloading_occurred) { + dictionary()->do_unloading(); constraints()->purge_loader_constraints(); resolution_errors()->purge_resolution_errors(); } diff -r 7fa57b65c27f -r c3990b8c710e test/compiler/classUnloading/anonymousClass/TestAnonymousClassUnloading.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/compiler/classUnloading/anonymousClass/TestAnonymousClassUnloading.java Mon Aug 25 08:20:17 2014 +0200 @@ -0,0 +1,130 @@ +/* + * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +import sun.hotspot.WhiteBox; +import sun.misc.Unsafe; +import sun.misc.IOUtils; + +import java.lang.reflect.Method; +import java.net.URL; +import java.net.URLConnection; + +/* + * @test TestAnonymousClassUnloading + * @bug 8054402 + * @summary "Tests unloading of anonymous classes." + * @library /testlibrary /testlibrary/whitebox + * @compile TestAnonymousClassUnloading.java + * @run main ClassFileInstaller TestAnonymousClassUnloading + * sun.hotspot.WhiteBox + * sun.hotspot.WhiteBox$WhiteBoxPermission + * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:-BackgroundCompilation TestAnonymousClassUnloading + */ +public class TestAnonymousClassUnloading { + private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox(); + private static final Unsafe UNSAFE = Unsafe.getUnsafe(); + private static int COMP_LEVEL_SIMPLE = 1; + private static int COMP_LEVEL_FULL_OPTIMIZATION = 4; + + /** + * We override hashCode here to be able to access this implementation + * via an Object reference (we cannot cast to TestAnonymousClassUnloading). + */ + @Override + public int hashCode() { + return 42; + } + + /** + * Does some work by using the anonymousClass. + * @param anonymousClass Class performing some work (will be unloaded) + */ + static private void doWork(Class anonymousClass) throws InstantiationException, IllegalAccessException { + // Create a new instance + Object anon = anonymousClass.newInstance(); + // We would like to call a method of anonymousClass here but we cannot cast because the class + // was loaded by a different class loader. One solution would be to use reflection but since + // we want C2 to implement the call as an IC we call Object::hashCode() here which actually + // calls anonymousClass::hashCode(). C2 will then implement this call as an IC. + if (anon.hashCode() != 42) { + new RuntimeException("Work not done"); + } + } + + /** + * Makes sure that method is compiled by forcing compilation if not yet compiled. + * @param m Method to be checked + */ + static private void makeSureIsCompiled(Method m) { + // Make sure background compilation is disabled + if (WHITE_BOX.getBooleanVMFlag("BackgroundCompilation")) { + throw new RuntimeException("Background compilation enabled"); + } + + // Check if already compiled + if (!WHITE_BOX.isMethodCompiled(m)) { + // If not, try to compile it with C2 + if(!WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION)) { + // C2 compiler not available, try to compile with C1 + WHITE_BOX.enqueueMethodForCompilation(m, COMP_LEVEL_SIMPLE); + } + // Because background compilation is disabled, method should now be compiled + if(!WHITE_BOX.isMethodCompiled(m)) { + throw new RuntimeException(m + " not compiled"); + } + } + } + + /** + * This test creates stale Klass* metadata referenced by a compiled IC. + * + * The following steps are performed: + * (1) An anonymous version of TestAnonymousClassUnloading is loaded by a custom class loader + * (2) The method doWork that calls a method of the anonymous class is compiled. The call + * is implemented as an IC referencing Klass* metadata of the anonymous class. + * (3) Unloading of the anonymous class is enforced. The IC now references dead metadata. + */ + static public void main(String[] args) throws Exception { + // (1) Load an anonymous version of this class using the corresponding Unsafe method + URL classUrl = TestAnonymousClassUnloading.class.getResource("TestAnonymousClassUnloading.class"); + URLConnection connection = classUrl.openConnection(); + byte[] classBytes = IOUtils.readFully(connection.getInputStream(), connection.getContentLength(), true); + Class anonymousClass = UNSAFE.defineAnonymousClass(TestAnonymousClassUnloading.class, classBytes, null); + + // (2) Make sure all paths of doWork are profiled and compiled + for (int i = 0; i < 100000; ++i) { + doWork(anonymousClass); + } + + // Make sure doWork is compiled now + Method doWork = TestAnonymousClassUnloading.class.getDeclaredMethod("doWork", Class.class); + makeSureIsCompiled(doWork); + + // (3) Throw away reference to anonymousClass to allow unloading + anonymousClass = null; + + // Force garbage collection to trigger unloading of anonymousClass + // Dead metadata reference to anonymousClass triggers JDK-8054402 + WHITE_BOX.fullGC(); + } +}