1 /*

     2  * Copyright (c) 2014, 2015, 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 8076110

    27  * @summary Redefine running methods that have cached resolution errors

    28  * @library /testlibrary

    29  * @modules java.instrument

    30  *          java.base/jdk.internal.org.objectweb.asm

    31  * @build RedefineClassHelper

    32  * @run main RedefineClassHelper

    33  * @run main/othervm -javaagent:redefineagent.jar -XX:TraceRedefineClasses=0x600 RedefineRunningMethodsWithResolutionErrors

    34  */

    35 

    36 import jdk.internal.org.objectweb.asm.ClassWriter;

    37 import jdk.internal.org.objectweb.asm.Label;

    38 import jdk.internal.org.objectweb.asm.MethodVisitor;

    39 import jdk.internal.org.objectweb.asm.Opcodes;

    40 

    41 import java.lang.reflect.InvocationTargetException;

    42 

    43 public class RedefineRunningMethodsWithResolutionErrors extends ClassLoader implements Opcodes {

    44 

    45     @Override

    46     protected Class<?> findClass(String name) throws ClassNotFoundException {

    47         if (name.equals("C")) {

    48             byte[] b = loadC(false);

    49             return defineClass(name, b, 0, b.length);

    50         } else {

    51             return super.findClass(name);

    52         }

    53     }

    54 

    55     private static byte[] loadC(boolean redefine) {

    56         ClassWriter cw = new ClassWriter(0);

    57 

    58         cw.visit(52, ACC_SUPER | ACC_PUBLIC, "C", null, "java/lang/Object", null);

    59         {

    60             MethodVisitor mv;

    61 

    62             mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "m", "()V", null, null);

    63             mv.visitCode();

    64 

    65             // First time we run we will:

    66             // 1) Cache resolution errors

    67             // 2) Redefine the class / method

    68             // 3) Try to read the resolution errors that were cached

    69             //

    70             // The redefined method will never run, throw error to be sure

    71             if (redefine) {

    72                 createThrowRuntimeExceptionCode(mv, "The redefined method was called");

    73             } else {

    74                 createMethodBody(mv);

    75             }

    76             mv.visitMaxs(3, 0);

    77             mv.visitEnd();

    78         }

    79         cw.visitEnd();

    80         return cw.toByteArray();

    81     }

    82 

    83     private static void createMethodBody(MethodVisitor mv) {

    84         Label classExists = new Label();

    85 

    86         // Cache resolution errors

    87         createLoadNonExistentClassCode(mv, classExists);

    88 

    89         // Redefine our own class and method

    90         mv.visitMethodInsn(INVOKESTATIC, "RedefineRunningMethodsWithResolutionErrors", "redefine", "()V");

    91 

    92         // Provoke the same error again to make sure the resolution error cache works

    93         createLoadNonExistentClassCode(mv, classExists);

    94 

    95         // Test passed

    96         mv.visitInsn(RETURN);

    97 

    98         mv.visitFrame(F_SAME, 0, new Object[0], 0, new Object[0]);

    99         mv.visitLabel(classExists);

   100 

   101         createThrowRuntimeExceptionCode(mv, "Loaded class that shouldn't exist (\"NonExistentClass\")");

   102     }

   103 

   104     private static void createLoadNonExistentClassCode(MethodVisitor mv, Label classExists) {

   105         Label tryLoadBegin = new Label();

   106         Label tryLoadEnd = new Label();

   107         Label catchLoadBlock = new Label();

   108         mv.visitTryCatchBlock(tryLoadBegin, tryLoadEnd, catchLoadBlock, "java/lang/NoClassDefFoundError");

   109 

   110         // Try to load a class that does not exist to provoke resolution errors

   111         mv.visitLabel(tryLoadBegin);

   112         mv.visitMethodInsn(INVOKESTATIC, "NonExistentClass", "nonExistentMethod", "()V");

   113         mv.visitLabel(tryLoadEnd);

   114 

   115         // No NoClassDefFoundError means NonExistentClass existed, which shouldn't happen

   116         mv.visitJumpInsn(GOTO, classExists);

   117 

   118         mv.visitFrame(F_SAME1, 0, new Object[0], 1, new Object[] { "java/lang/NoClassDefFoundError" });

   119         mv.visitLabel(catchLoadBlock);

   120 

   121         // Ignore the expected NoClassDefFoundError

   122         mv.visitInsn(POP);

   123     }

   124 

   125     private static void createThrowRuntimeExceptionCode(MethodVisitor mv, String msg) {

   126         mv.visitTypeInsn(NEW, "java/lang/RuntimeException");

   127         mv.visitInsn(DUP);

   128         mv.visitLdcInsn(msg);

   129         mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");

   130         mv.visitInsn(ATHROW);

   131     }

   132 

   133     private static Class<?> c;

   134 

   135     public static void redefine() throws Exception {

   136         RedefineClassHelper.redefineClass(c, loadC(true));

   137     }

   138 

   139     public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {

   140         c = Class.forName("C", true, new RedefineRunningMethodsWithResolutionErrors());

   141         c.getMethod("m").invoke(null);

   142     }

   143 }