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/*
* Copyright (c) 2014, 2015, 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 8076110
* @summary Redefine running methods that have cached resolution errors
* @library /testlibrary
* @modules java.instrument
* java.base/jdk.internal.org.objectweb.asm
* @build RedefineClassHelper
* @run main RedefineClassHelper
* @run main/othervm -javaagent:redefineagent.jar RedefineRunningMethodsWithResolutionErrors
*/
import jdk.internal.org.objectweb.asm.ClassWriter;
import jdk.internal.org.objectweb.asm.Label;
import jdk.internal.org.objectweb.asm.MethodVisitor;
import jdk.internal.org.objectweb.asm.Opcodes;
import java.lang.reflect.InvocationTargetException;
public class RedefineRunningMethodsWithResolutionErrors extends ClassLoader implements Opcodes {
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
if (name.equals("C")) {
byte[] b = loadC(false);
return defineClass(name, b, 0, b.length);
} else {
return super.findClass(name);
}
}
private static byte[] loadC(boolean redefine) {
ClassWriter cw = new ClassWriter(0);
cw.visit(52, ACC_SUPER | ACC_PUBLIC, "C", null, "java/lang/Object", null);
{
MethodVisitor mv;
mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "m", "()V", null, null);
mv.visitCode();
// First time we run we will:
// 1) Cache resolution errors
// 2) Redefine the class / method
// 3) Try to read the resolution errors that were cached
//
// The redefined method will never run, throw error to be sure
if (redefine) {
createThrowRuntimeExceptionCode(mv, "The redefined method was called");
} else {
createMethodBody(mv);
}
mv.visitMaxs(3, 0);
mv.visitEnd();
}
cw.visitEnd();
return cw.toByteArray();
}
private static void createMethodBody(MethodVisitor mv) {
Label classExists = new Label();
// Cache resolution errors
createLoadNonExistentClassCode(mv, classExists);
// Redefine our own class and method
mv.visitMethodInsn(INVOKESTATIC, "RedefineRunningMethodsWithResolutionErrors", "redefine", "()V");
// Provoke the same error again to make sure the resolution error cache works
createLoadNonExistentClassCode(mv, classExists);
// Test passed
mv.visitInsn(RETURN);
mv.visitFrame(F_SAME, 0, new Object[0], 0, new Object[0]);
mv.visitLabel(classExists);
createThrowRuntimeExceptionCode(mv, "Loaded class that shouldn't exist (\"NonExistentClass\")");
}
private static void createLoadNonExistentClassCode(MethodVisitor mv, Label classExists) {
Label tryLoadBegin = new Label();
Label tryLoadEnd = new Label();
Label catchLoadBlock = new Label();
mv.visitTryCatchBlock(tryLoadBegin, tryLoadEnd, catchLoadBlock, "java/lang/NoClassDefFoundError");
// Try to load a class that does not exist to provoke resolution errors
mv.visitLabel(tryLoadBegin);
mv.visitMethodInsn(INVOKESTATIC, "NonExistentClass", "nonExistentMethod", "()V");
mv.visitLabel(tryLoadEnd);
// No NoClassDefFoundError means NonExistentClass existed, which shouldn't happen
mv.visitJumpInsn(GOTO, classExists);
mv.visitFrame(F_SAME1, 0, new Object[0], 1, new Object[] { "java/lang/NoClassDefFoundError" });
mv.visitLabel(catchLoadBlock);
// Ignore the expected NoClassDefFoundError
mv.visitInsn(POP);
}
private static void createThrowRuntimeExceptionCode(MethodVisitor mv, String msg) {
mv.visitTypeInsn(NEW, "java/lang/RuntimeException");
mv.visitInsn(DUP);
mv.visitLdcInsn(msg);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");
mv.visitInsn(ATHROW);
}
private static Class<?> c;
public static void redefine() throws Exception {
RedefineClassHelper.redefineClass(c, loadC(true));
}
public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
c = Class.forName("C", true, new RedefineRunningMethodsWithResolutionErrors());
c.getMethod("m").invoke(null);
}
}
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