--- /dev/null 2014-11-04 10:00:21.340256507 -0500 +++ new/compiler/jsr292/RedefineMethodUsedByMultipleMethodHandles.java 2014-11-07 14:34:15.769740920 -0500 @@ -0,0 +1,184 @@ +/* + * 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. + * + */ + +/** + * @test + * @bug 8059556 + * @compile -XDignore.symbol.file RedefineMethodUsedByMultipleMethodHandles.java + * @run main RedefineMethodUsedByMultipleMethodHandles + */ + +import java.io.*; +import java.lang.instrument.*; +import java.lang.invoke.*; +import java.lang.invoke.MethodHandles.Lookup; +import java.lang.management.*; +import java.lang.reflect.*; +import java.nio.file.*; +import java.security.*; +import java.util.jar.*; + +import javax.tools.*; + +import jdk.internal.org.objectweb.asm.*; + +public class RedefineMethodUsedByMultipleMethodHandles { + + static class Foo { + public static Object getName() { + return "foo"; + } + } + + public static void main(String[] args) throws Throwable { + + Lookup lookup = MethodHandles.lookup(); + Method fooMethod = Foo.class.getDeclaredMethod("getName"); + + // fooMH2 displaces fooMH1 from the MemberNamesTable + MethodHandle fooMH1 = lookup.unreflect(fooMethod); + MethodHandle fooMH2 = lookup.unreflect(fooMethod); + + System.out.println("before invoke fooMH1 = " + fooMH1); + System.out.println("before invoke fooMH2 = " + fooMH2); + + System.out.println("fooMH1.invoke = " + fooMH1.invokeExact()); + System.out.println("fooMH2.invoke = " + fooMH2.invokeExact()); + + System.out.println("after invoke fooMH1 = " + fooMH1); + System.out.println("after invoke fooMH2 = " + fooMH2); + + // Redefining Foo.getName() causes vmtarget to be updated + // in fooMH2 but not fooMH1 + redefineFoo(); + + // Full GC causes fooMH1.vmtarget to be deallocated + System.gc(); + + System.out.println("after redef+gc fooMH1 = " + fooMH1); + System.out.println("after redef+gc fooMH2 = " + fooMH2); + + System.out.println("fooMH1.invoke = " + fooMH1.invokeExact()); + System.out.println("fooMH2.invoke = " + fooMH2.invokeExact()); + } + + /** + * Adds the class file bytes for {@code c} to {@code jar}. + */ + static void add(JarOutputStream jar, Class c) throws IOException { + String classAsPath = c.getName().replace('.', '/') + ".class"; + jar.putNextEntry(new JarEntry(classAsPath)); + InputStream stream = c.getClassLoader().getResourceAsStream(classAsPath); + + int b; + while ((b = stream.read()) != -1) { + jar.write(b); + } + } + + static void redefineFoo() throws Exception { + Manifest manifest = new Manifest(); + manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0"); + Attributes mainAttrs = manifest.getMainAttributes(); + mainAttrs.putValue("Agent-Class", FooAgent.class.getName()); + mainAttrs.putValue("Can-Redefine-Classes", "true"); + mainAttrs.putValue("Can-Retransform-Classes", "true"); + + Path jar = Files.createTempFile("myagent", ".jar"); + try { + JarOutputStream jarStream = new JarOutputStream(new FileOutputStream(jar.toFile()), manifest); + add(jarStream, FooAgent.class); + add(jarStream, FooTransformer.class); + jarStream.close(); + runAgent(jar); + } finally { + Files.deleteIfExists(jar); + } + } + + public static void runAgent(Path agent) throws Exception { + String vmName = ManagementFactory.getRuntimeMXBean().getName(); + int p = vmName.indexOf('@'); + assert p != -1 : "VM name not in @ format: " + vmName; + String pid = vmName.substring(0, p); + ClassLoader cl = ToolProvider.getSystemToolClassLoader(); + Class c = Class.forName("com.sun.tools.attach.VirtualMachine", true, cl); + Method attach = c.getDeclaredMethod("attach", String.class); + Method loadAgent = c.getDeclaredMethod("loadAgent", String.class); + Method detach = c.getDeclaredMethod("detach"); + Object vm = attach.invoke(null, pid); + loadAgent.invoke(vm, agent.toString()); + detach.invoke(vm); + } + + public static class FooAgent { + + public static void agentmain(@SuppressWarnings("unused") String args, Instrumentation inst) throws Exception { + assert inst.isRedefineClassesSupported(); + assert inst.isRetransformClassesSupported(); + inst.addTransformer(new FooTransformer(), true); + Class[] classes = inst.getAllLoadedClasses(); + for (int i = 0; i < classes.length; i++) { + Class c = classes[i]; + if (c == Foo.class) { + inst.retransformClasses(new Class[]{c}); + } + } + } + } + +// static class FooTransformer implements ClassFileTransformer, Opcodes { + static class FooTransformer implements ClassFileTransformer { + + @Override + public byte[] transform(ClassLoader cl, String className, Class classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { + if (Foo.class.equals(classBeingRedefined)) { + System.out.println("redefining " + classBeingRedefined); + ClassReader cr = new ClassReader(classfileBuffer); + ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_FRAMES); + ClassVisitor adapter = new ClassVisitor(Opcodes.ASM5, cw) { + @Override + public MethodVisitor visitMethod(int access, String base, String desc, String signature, String[] exceptions) { + MethodVisitor mv = cv.visitMethod(access, base, desc, signature, exceptions); + if (mv != null) { + mv = new MethodVisitor(Opcodes.ASM5, mv) { + @Override + public void visitLdcInsn(Object cst) { + System.out.println("replacing \"" + cst + "\" with \"bar\""); + mv.visitLdcInsn("bar"); + } + }; + } + return mv; + } + }; + + cr.accept(adapter, ClassReader.SKIP_FRAMES); + cw.visitEnd(); + return cw.toByteArray(); + } + return classfileBuffer; + } + } +}