Java example source code file (LVTHarness.java)

This example Java source code file (LVTHarness.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

aliveranges, annotation, arraylist, assertionerror, elementkey, error, file, javactask, list, localvariabletable_attribute, lvtharness, override, string, stringbuilder, unexpectedentry, util

The LVTHarness.java Java example source code

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * 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
 * published by the Free Software Foundation.
 *
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 7047734 8027660
 * @summary The LVT is not generated correctly during some try/catch scenarios;
 *          javac crash while creating LVT entry for a local variable defined in
 *          an inner block
 * @library /tools/javac/lib
 * @build JavacTestingAbstractProcessor LVTHarness
 * @run main LVTHarness
 */

import java.io.File;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.util.Set;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;

import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;

import com.sun.source.util.JavacTask;
import com.sun.tools.classfile.Attribute;
import com.sun.tools.classfile.ClassFile;
import com.sun.tools.classfile.ConstantPool;
import com.sun.tools.classfile.ConstantPoolException;
import com.sun.tools.classfile.Code_attribute;
import com.sun.tools.classfile.ConstantPool.InvalidIndex;
import com.sun.tools.classfile.ConstantPool.UnexpectedEntry;
import com.sun.tools.classfile.Descriptor.InvalidDescriptor;
import com.sun.tools.classfile.LocalVariableTable_attribute;
import com.sun.tools.classfile.Method;

import static javax.tools.StandardLocation.*;
import static com.sun.tools.classfile.LocalVariableTable_attribute.Entry;
import static javax.tools.JavaFileObject.Kind.SOURCE;

public class LVTHarness {

    static int nerrors = 0;

    static final JavaCompiler comp = ToolProvider.getSystemJavaCompiler();
    static final StandardJavaFileManager fm = comp.getStandardFileManager(null, null, null);

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

        String testDir = System.getProperty("test.src");
        fm.setLocation(SOURCE_PATH, Arrays.asList(new File(testDir, "tests")));

        // Make sure classes are written to scratch dir.
        fm.setLocation(CLASS_OUTPUT, Arrays.asList(new File(".")));

        for (JavaFileObject jfo : fm.list(SOURCE_PATH, "", Collections.singleton(SOURCE), true)) {
            new LVTHarness(jfo).check();
        }
        if (nerrors > 0) {
            throw new AssertionError("Errors were found");
        }
    }


    JavaFileObject jfo;
    Map<ElementKey, AliveRanges> aliveRangeMap = new HashMap<>();
    Set<String> declaredKeys = new HashSet<>();
    List<ElementKey> seenAliveRanges = new ArrayList<>();

    protected LVTHarness(JavaFileObject jfo) {
        this.jfo = jfo;
    }

    protected void check() throws Exception {

        JavacTask ct = (JavacTask) comp.getTask(null, fm, null, Arrays.asList("-g"),
                                                null, Arrays.asList(jfo));
        System.err.println("compiling code " + jfo);
        ct.setProcessors(Collections.singleton(new AliveRangeFinder()));
        if (!ct.call()) {
            throw new AssertionError("Error during compilation");
        }


        File javaFile = new File(jfo.getName());
        File classFile = new File(javaFile.getName().replace(".java", ".class"));
        checkClassFile(classFile);

        //check all candidates have been used up
        for (Map.Entry<ElementKey, AliveRanges> entry : aliveRangeMap.entrySet()) {
            if (!seenAliveRanges.contains(entry.getKey())) {
                error("Redundant @AliveRanges annotation on method " +
                        entry.getKey().elem);
            }
        }
    }

    void checkClassFile(File file)
            throws IOException, ConstantPoolException, InvalidDescriptor {
        ClassFile classFile = ClassFile.read(file);
        ConstantPool constantPool = classFile.constant_pool;

        //lets get all the methods in the class file.
        for (Method method : classFile.methods) {
            for (ElementKey elementKey: aliveRangeMap.keySet()) {
                String methodDesc = method.getName(constantPool) +
                        method.descriptor.getParameterTypes(constantPool);
                if (methodDesc.equals(elementKey.elem.toString())) {
                    checkMethod(constantPool, method, aliveRangeMap.get(elementKey));
                    seenAliveRanges.add(elementKey);
                }
            }
        }
    }

    void checkMethod(ConstantPool constantPool, Method method, AliveRanges ranges)
            throws InvalidIndex, UnexpectedEntry {
        Code_attribute code = (Code_attribute) method.attributes.get(Attribute.Code);
        LocalVariableTable_attribute lvt =
            (LocalVariableTable_attribute) (code.attributes.get(Attribute.LocalVariableTable));
        List<String> infoFromRanges = convertToStringList(ranges);
        List<String> infoFromLVT = convertToStringList(constantPool, lvt);

        // infoFromRanges most be contained in infoFromLVT
        int i = 0;
        int j = 0;
        while (i < infoFromRanges.size() && j < infoFromLVT.size()) {
            int comparison = infoFromRanges.get(i).compareTo(infoFromLVT.get(j));
            if (comparison == 0) {
                i++; j++;
            } else if (comparison > 0) {
                j++;
            } else {
                break;
            }
        }

        if (i < infoFromRanges.size()) {
            error(infoFromLVT, infoFromRanges);
        }
    }

    List<String> convertToStringList(AliveRanges ranges) {
        List<String> result = new ArrayList<>();
        for (Annotation anno : ranges.value()) {
            AliveRange range = (AliveRange)anno;
            String str = formatLocalVariableData(range.varName(),
                    range.bytecodeStart(), range.bytecodeLength());
            result.add(str);
        }
        Collections.sort(result);
        return result;
    }

    List<String> convertToStringList(ConstantPool constantPool,
            LocalVariableTable_attribute lvt) throws InvalidIndex, UnexpectedEntry {
        List<String> result = new ArrayList<>();
        for (Entry entry : lvt.local_variable_table) {
            String str = formatLocalVariableData(constantPool.getUTF8Value(entry.name_index),
                    entry.start_pc, entry.length);
            result.add(str);
        }
        Collections.sort(result);
        return result;
    }

    String formatLocalVariableData(String varName, int start, int length) {
        StringBuilder sb = new StringBuilder()
                    .append("var name: ").append(varName)
                    .append(" start: ").append(start)
                    .append(" length: ").append(length);
        return sb.toString();
    }

    protected void error(List<String> infoFromLVT, List infoFromRanges) {
        nerrors++;
        System.err.printf("Error occurred while checking file: %s\n", jfo.getName());
        System.err.println("The range info from the annotations is");
        printStringListToErrOutput(infoFromRanges);
        System.err.println();
        System.err.println("And the range info from the class file is");
        printStringListToErrOutput(infoFromLVT);
        System.err.println();
    }

    void printStringListToErrOutput(List<String> list) {
        for (String s : list) {
            System.err.println("\t" + s);
        }
    }

    protected void error(String msg) {
        nerrors++;
        System.err.printf("Error occurred while checking file: %s\nreason: %s\n",
                jfo.getName(), msg);
    }

    class AliveRangeFinder extends JavacTestingAbstractProcessor {

        @Override
        public boolean process(Set<? extends TypeElement> annotations,
            RoundEnvironment roundEnv) {
            if (roundEnv.processingOver())
                return true;

            TypeElement aliveRangeAnno = elements.getTypeElement("AliveRanges");

            if (!annotations.contains(aliveRangeAnno)) {
                error("no @AliveRanges annotation found in test class");
            }

            for (Element elem: roundEnv.getElementsAnnotatedWith(aliveRangeAnno)) {
                Annotation annotation = elem.getAnnotation(AliveRanges.class);
                aliveRangeMap.put(new ElementKey(elem), (AliveRanges)annotation);
            }
            return true;
        }
    }

    class ElementKey {

        String key;
        Element elem;

        public ElementKey(Element elem) {
            this.elem = elem;
            this.key = computeKey(elem);
        }

        @Override
        public boolean equals(Object obj) {
            if (obj instanceof ElementKey) {
                ElementKey other = (ElementKey)obj;
                return other.key.equals(key);
            }
            return false;
        }

        @Override
        public int hashCode() {
            return key.hashCode();
        }

        String computeKey(Element e) {
            StringBuilder buf = new StringBuilder();
            while (e != null) {
                buf.append(e.toString());
                e = e.getEnclosingElement();
            }
            buf.append(jfo.getName());
            return buf.toString();
        }

        @Override
        public String toString() {
            return "Key{" + key + "}";
        }
    }

}