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
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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
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22  */
23 
24 /*
25  * @test
26  * @bug 8015499
27  * @summary javac, Gen is generating extra checkcast instructions in some corner cases
28  * @modules jdk.jdeps/com.sun.tools.classfile
29  *          jdk.compiler/com.sun.tools.javac.util
30  * @run main DoubleCastTest
31  */
32 
33 import java.util.List;
34 import java.util.ArrayList;
35 import com.sun.tools.classfile.*;
36 import com.sun.tools.javac.util.Assert;
37 
38 public class DoubleCastTest {
39     class C {
40         Object x;
41         Object m() { return null; }
42         void m1(byte[] b) {}
43         void m2() {
44             Object o;
45             Object[] os = null;
46             m1((byte[])(o = null));
47             m1((byte[])o);
48             m1((byte[])(o == null ? o : o));
49             m1((byte[])m());
50             m1((byte[])os[0]);
51             m1((byte[])this.x);
52             m1((byte[])((byte []) (o = null)));
53         }
54     }
55 
56     public static void main(String... cmdline) throws Exception {
57 
58         ClassFile cls = ClassFile.read(DoubleCastTest.class.getResourceAsStream("DoubleCastTest$C.class"));
59         for (Method m: cls.methods)
60             check(m);
61     }
62 
63     static void check(Method m) throws Exception {
64         boolean last_is_cast = false;
65         int last_ref = 0;
66         Code_attribute ea = (Code_attribute)m.attributes.get(Attribute.Code);
67         for (Instruction i : ea.getInstructions()) {
68             if (i.getOpcode() == Opcode.CHECKCAST) {
69                 Assert.check
70                     (!(last_is_cast && last_ref == i.getUnsignedShort(1)),
71                      "Double cast found - Test failed");
72                 last_is_cast = true;
73                 last_ref = i.getUnsignedShort(1);
74             } else {
75                 last_is_cast = false;
76             }
77         }
78     }
79 }
80