1/*
2 * Copyright (c) 2013, 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 8022186
27 * @summary javac generates dead code if a try with an empty body has a finalizer
28 * @modules jdk.jdeps/com.sun.tools.classfile
29 *          jdk.compiler/com.sun.tools.javac.util
30 */
31
32import com.sun.tools.classfile.Attribute;
33import com.sun.tools.classfile.ClassFile;
34import com.sun.tools.classfile.Code_attribute;
35import com.sun.tools.classfile.ConstantPool;
36import com.sun.tools.classfile.ConstantPool.CONSTANT_String_info;
37import com.sun.tools.classfile.ConstantPool.CPInfo;
38import com.sun.tools.classfile.ConstantPool.InvalidIndex;
39import com.sun.tools.classfile.Instruction;
40import com.sun.tools.classfile.Instruction.KindVisitor;
41import com.sun.tools.classfile.Instruction.TypeKind;
42import com.sun.tools.classfile.Method;
43import com.sun.tools.javac.util.Assert;
44import java.io.BufferedInputStream;
45import java.nio.file.Files;
46import java.nio.file.Path;
47import java.nio.file.Paths;
48
49public class DeadCodeGeneratedForEmptyTryTest {
50
51    public static void main(String[] args) throws Exception {
52        new DeadCodeGeneratedForEmptyTryTest().run();
53    }
54
55    void run() throws Exception {
56        checkClassFile(Paths.get(System.getProperty("test.classes"),
57                this.getClass().getName() + "$Test.class"));
58    }
59
60    int utf8Index;
61    int numberOfRefToStr = 0;
62    ConstantPool constantPool;
63
64    void checkClassFile(final Path path) throws Exception {
65        ClassFile classFile = ClassFile.read(
66                new BufferedInputStream(Files.newInputStream(path)));
67        constantPool = classFile.constant_pool;
68        utf8Index = constantPool.getUTF8Index("STR_TO_LOOK_FOR");
69        for (Method method: classFile.methods) {
70            if (method.getName(constantPool).equals("methodToLookFor")) {
71                Code_attribute codeAtt = (Code_attribute)method.attributes.get(Attribute.Code);
72                for (Instruction inst: codeAtt.getInstructions()) {
73                    inst.accept(codeVisitor, null);
74                }
75            }
76        }
77        Assert.check(numberOfRefToStr == 1,
78                "There should only be one reference to a CONSTANT_String_info structure in the generated code");
79    }
80
81    CodeVisitor codeVisitor = new CodeVisitor();
82
83    class CodeVisitor implements KindVisitor<Void, Void> {
84
85        void checkIndirectRefToString(int cp_index) {
86            try {
87                CPInfo cInfo = constantPool.get(cp_index);
88                if (cInfo instanceof CONSTANT_String_info) {
89                    CONSTANT_String_info strInfo = (CONSTANT_String_info)cInfo;
90                    if (strInfo.string_index == utf8Index) {
91                        numberOfRefToStr++;
92                    }
93                }
94            } catch (InvalidIndex ex) {
95                throw new AssertionError("invalid constant pool index at " + cp_index);
96            }
97        }
98
99        @Override
100        public Void visitNoOperands(Instruction instr, Void p) {
101            return null;
102        }
103
104        @Override
105        public Void visitArrayType(Instruction instr, TypeKind kind, Void p) {
106            return null;
107        }
108
109        @Override
110        public Void visitBranch(Instruction instr, int offset, Void p) {
111            return null;
112        }
113
114        @Override
115        public Void visitConstantPoolRef(Instruction instr, int index, Void p) {
116            checkIndirectRefToString(index);
117            return null;
118        }
119
120        @Override
121        public Void visitConstantPoolRefAndValue(Instruction instr, int index, int value, Void p) {
122            checkIndirectRefToString(index);
123            return null;
124        }
125
126        @Override
127        public Void visitLocal(Instruction instr, int index, Void p) {
128            return null;
129        }
130
131        @Override
132        public Void visitLocalAndValue(Instruction instr, int index, int value, Void p) {
133            return null;
134        }
135
136        @Override
137        public Void visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, Void p) {
138            return null;
139        }
140
141        @Override
142        public Void visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, Void p) {
143            return null;
144        }
145
146        @Override
147        public Void visitValue(Instruction instr, int value, Void p) {
148            return null;
149        }
150
151        @Override
152        public Void visitUnknown(Instruction instr, Void p) {
153            return null;
154        }
155
156    }
157
158    public class Test {
159        void methodToLookFor() {
160            try {
161            } finally {
162                System.out.println("STR_TO_LOOK_FOR");
163            }
164        }
165    }
166}
167