8054402: "klass->is_loader_alive(_is_alive)) failed: must be alive" for anonymous classes

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

hotspot/test/compiler/classUnloading/anonymousClass/TestAnonymousClassUnloading.java

@@ -0,0 +1,128 @@
+/*
+ * 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
+ * @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();
+    }
+}