1 /*
   2  * Copyright (c) 2016, 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 import java.lang.invoke.*;
  26 
  27 /**
  28  * @test
  29  * @bug 8148752
  30  * @summary Test correct casting of MH arguments during inlining.
  31  * @run main LongReferenceCastingTest
  32  */
  33 public class LongReferenceCastingTest {
  34     static final String MY_STRING = "myString";
  35     static final MethodHandle MH;
  36 
  37     static {
  38         try {
  39             MethodHandles.Lookup lookup = MethodHandles.lookup();
  40             MethodType mt = MethodType.methodType(String.class, long.class, Object.class, String.class);
  41             MH = lookup.findVirtual(LongReferenceCastingTest.class, "myMethod", mt);
  42         } catch (Exception e) {
  43             throw new Error(e);
  44         }
  45     }
  46 
  47     public String myMethod(long l, Object o, String s) {
  48         // The long argument occupies two stack slots, causing C2 to treat it as
  49         // two arguments and casting the fist one two long and the second one to Object.
  50         // As a result, Object o is casted to String and the o.toString() call is
  51         // inlined as String::toString(). We fail at runtime because 'o' is not a String.
  52         return o.toString();
  53     }
  54 
  55     public String toString() {
  56         return MY_STRING;
  57     }
  58 
  59     public static void main(String[] args) throws Exception {
  60         LongReferenceCastingTest test = new LongReferenceCastingTest();
  61         try {
  62             for (int i = 0; i < 20_000; ++i) {
  63                 if (!test.invoke().equals(MY_STRING)) {
  64                     throw new RuntimeException("Invalid string");
  65                 }
  66             }
  67         } catch (Throwable t) {
  68             throw new RuntimeException("Test failed", t);
  69         }
  70     }
  71 
  72     public String invoke() throws Throwable {
  73         return (String) MH.invokeExact(this, 0L, (Object)this, MY_STRING);
  74     }
  75 }