Unjitable.java

/*
 * fb-contrib - Auxiliary detectors for Java programs
 * Copyright (C) 2005-2017 Dave Brosius
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.mebigfatguy.fbcontrib.detect;

import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;

import com.mebigfatguy.fbcontrib.utils.BugType;
import com.mebigfatguy.fbcontrib.utils.Values;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;

/**
 * looks for methods that are bigger than 8000 bytes, as these methods are ignored by the jit for compilation, causing them to always be interpreted.
 */
public class Unjitable extends PreorderVisitor implements Detector {

    private static final int UNJITABLE_CODE_LENGTH = 8000;

    private BugReporter bugReporter;

    public Unjitable(BugReporter bugReporter) {
        this.bugReporter = bugReporter;
    }

    /**
     * implements the visitor to accept the class for visiting
     *
     * @param classContext
     *            the context object of the currently parsed class
     */
    @Override
    public void visitClassContext(ClassContext classContext) {
        JavaClass cls = classContext.getJavaClass();
        cls.accept(this);
    }

    /**
     * implements the visitor to look at the size of the method. static initializer are ignored as these will only be executed once anyway.
     *
     * @param obj
     *            the context object of the currently parsed method
     */
    @Override
    public void visitCode(Code obj) {

        Method m = getMethod();
        if ((!m.isStatic() || !Values.STATIC_INITIALIZER.equals(m.getName())) && (!m.getName().contains("enum constant"))) { // a findbugs thing!!
            byte[] code = obj.getCode();
            if (code.length >= UNJITABLE_CODE_LENGTH) {
                bugReporter.reportBug(new BugInstance(this, BugType.UJM_UNJITABLE_METHOD.name(), NORMAL_PRIORITY).addClass(this).addMethod(this)
                        .addString("Code Bytes: " + code.length));
            }
        }
    }

    /**
     * overrides the visitor, but not used.
     */
    @Override
    public void report() {
        // bugs are reported in visitCode
    }
}