/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

/*

 * @test

 * @bug 8022186

 * @summary javac generates dead code if a try with an empty body has a finalizer

 * @modules jdk.jdeps/com.sun.tools.classfile

 *          jdk.compiler/com.sun.tools.javac.util

 */

import com.sun.tools.classfile.Attribute;

import com.sun.tools.classfile.ClassFile;

import com.sun.tools.classfile.Code_attribute;

import com.sun.tools.classfile.ConstantPool;

import com.sun.tools.classfile.ConstantPool.CONSTANT_String_info;

import com.sun.tools.classfile.ConstantPool.CPInfo;

import com.sun.tools.classfile.ConstantPool.InvalidIndex;

import com.sun.tools.classfile.Instruction;

import com.sun.tools.classfile.Instruction.KindVisitor;

import com.sun.tools.classfile.Instruction.TypeKind;

import com.sun.tools.classfile.Method;

import com.sun.tools.javac.util.Assert;

import java.io.BufferedInputStream;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

public class DeadCodeGeneratedForEmptyTryTest {

    public static void main(String[] args) throws Exception {

        new DeadCodeGeneratedForEmptyTryTest().run();

    }

    void run() throws Exception {

        checkClassFile(Paths.get(System.getProperty("test.classes"),

                this.getClass().getName() + "$Test.class"));

    }

    int utf8Index;

    int numberOfRefToStr = 0;

    ConstantPool constantPool;

    void checkClassFile(final Path path) throws Exception {

        ClassFile classFile = ClassFile.read(

                new BufferedInputStream(Files.newInputStream(path)));

        constantPool = classFile.constant_pool;

        utf8Index = constantPool.getUTF8Index("STR_TO_LOOK_FOR");

        for (Method method: classFile.methods) {

            if (method.getName(constantPool).equals("methodToLookFor")) {

                Code_attribute codeAtt = (Code_attribute)method.attributes.get(Attribute.Code);

                for (Instruction inst: codeAtt.getInstructions()) {

                    inst.accept(codeVisitor, null);

                }

            }

        }

        Assert.check(numberOfRefToStr == 1,

                "There should only be one reference to a CONSTANT_String_info structure in the generated code");

    }

    CodeVisitor codeVisitor = new CodeVisitor();

    class CodeVisitor implements KindVisitor<Void, Void> {

        void checkIndirectRefToString(int cp_index) {

            try {

                CPInfo cInfo = constantPool.get(cp_index);

                if (cInfo instanceof CONSTANT_String_info) {

                    CONSTANT_String_info strInfo = (CONSTANT_String_info)cInfo;

                    if (strInfo.string_index == utf8Index) {

                        numberOfRefToStr++;

                    }

                }

            } catch (InvalidIndex ex) {

                throw new AssertionError("invalid constant pool index at " + cp_index);

            }

        }

        @Override

        public Void visitNoOperands(Instruction instr, Void p) {

            return null;

        }

        @Override

        public Void visitArrayType(Instruction instr, TypeKind kind, Void p) {

            return null;

        }

        @Override

        public Void visitBranch(Instruction instr, int offset, Void p) {

            return null;

        }

        @Override

        public Void visitConstantPoolRef(Instruction instr, int index, Void p) {

            checkIndirectRefToString(index);

            return null;

        }

        @Override

        public Void visitConstantPoolRefAndValue(Instruction instr, int index, int value, Void p) {

            checkIndirectRefToString(index);

            return null;

        }

        @Override

        public Void visitLocal(Instruction instr, int index, Void p) {

            return null;

        }

        @Override

        public Void visitLocalAndValue(Instruction instr, int index, int value, Void p) {

            return null;

        }

        @Override

        public Void visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, Void p) {

            return null;

        }

        @Override

        public Void visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, Void p) {

            return null;

        }

        @Override

        public Void visitValue(Instruction instr, int value, Void p) {

            return null;

        }

        @Override

        public Void visitUnknown(Instruction instr, Void p) {

            return null;

        }

    }

    public class Test {

        void methodToLookFor() {

            try {

            } finally {

                System.out.println("STR_TO_LOOK_FOR");

            }

        }

    }

}