DoubleCastTest.java revision 2942:08092deced3f 
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 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
33import java.util.List;
34import java.util.ArrayList;
35import com.sun.tools.classfile.*;
36import com.sun.tools.javac.util.Assert;
37
38public 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