1 /*
   2  * Copyright (c) 2020, 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 8238550
  27  * @summary Test that verifer assignability checks involving the 'this' pointer
  28  *          work ok for hidden classes.
  29  * @compile FieldInSuperSub.jasm
  30  * @run main/othervm -Xverify:remote FieldInSuper
  31  */
  32 
  33 import java.io.ByteArrayOutputStream;
  34 import java.io.File;
  35 import java.io.FileInputStream;
  36 import java.lang.invoke.MethodHandles;
  37 import java.lang.invoke.MethodHandles.Lookup;
  38 import static java.lang.invoke.MethodHandles.Lookup.ClassOption.*;
  39 import java.nio.file.Path;
  40 import java.nio.file.Paths;
  41 
  42 public class FieldInSuper {
  43 
  44     static final Path CLASSES_DIR = Paths.get(System.getProperty("test.classes"));
  45     String hello = "hello";
  46 
  47     static byte[] readClassFile(String classFileName) throws Exception {
  48         File classFile = new File(CLASSES_DIR + File.separator + classFileName);
  49         try (FileInputStream in = new FileInputStream(classFile);
  50              ByteArrayOutputStream out = new ByteArrayOutputStream()) {
  51             int b;
  52             while ((b = in.read()) != -1) {
  53                 out.write(b);
  54             }
  55             return out.toByteArray();
  56         }
  57     }
  58 
  59     public static void main(String[] args) throws Throwable {
  60         Lookup lookup = MethodHandles.lookup();
  61         byte[] bytes = readClassFile("FieldInSuperSub.class");
  62 
  63         // Define a hidden class that loads the 'this' pointer and then
  64         // references field 'hello' using:
  65         //   getfield Field FieldInSuper.hello:"Ljava/lang/String;";
  66         // This will cause the verifier to check that the 'this' pointer for
  67         // the hidden class is assignable to FieldInSuper.
  68         Class<?> c = lookup.defineHiddenClass(bytes, true, NESTMATE).lookupClass();
  69         Object fss = c.newInstance();
  70         c.getMethod("printMe").invoke(fss);
  71     }
  72 
  73 }