BadFields.java

/* Soot - a J*va Optimization Framework
 * Copyright (C) 2003 Ondrej Lhotak
 *
 * 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 soot.tools;
import soot.*;
import java.util.*;
import soot.jimple.*;
import soot.jimple.toolkits.callgraph.*;

public class BadFields extends SceneTransformer {
    public static void main(String[] args) 
    {
	PackManager.v().getPack("cg").add(
	    new Transform("cg.badfields", new BadFields()));
	soot.Main.main(args);
    }

    private SootClass lastClass;
    private SootClass currentClass;

    protected void internalTransform(String phaseName, Map options)
    {
        lastClass = null;

        for( Iterator clIt = Scene.v().getApplicationClasses().iterator(); clIt.hasNext(); ) {

            final SootClass cl = (SootClass) clIt.next();
            currentClass = cl;
            handleClass( cl );
            for( Iterator it = cl.methodIterator(); it.hasNext(); ) {
                handleMethod( (SootMethod) it.next() );
            }
        }
        Scene.v().setCallGraph( new CallGraph() );
    }

    private void handleClass( SootClass cl ) {
        for( Iterator fIt = cl.getFields().iterator(); fIt.hasNext(); ) {
            final SootField f = (SootField) fIt.next();
            if( !f.isStatic() ) continue;
            String typeName = f.getType().toString();
            if( typeName.equals( "java.lang.Class" ) ) continue;
            if( f.isFinal() ) {
                if( f.getType() instanceof PrimType ) continue;
                if( typeName.equals( "java.io.PrintStream" ) ) continue;
                if( typeName.equals( "java.lang.String" ) ) continue;
                if( typeName.equals( "java.lang.Object" ) ) continue;
                if( typeName.equals( "java.lang.Integer" ) ) continue;
                if( typeName.equals( "java.lang.Boolean" ) ) continue;
            }
            warn( "Bad field "+f );
        }
    }

    private void warn( String warning ) {
        if( lastClass != currentClass ) 
            G.v().out.println( "In class "+currentClass );
        lastClass = currentClass;
        G.v().out.println( "  "+warning );
    }

    private void handleMethod( SootMethod m ) {
        if( !m.isConcrete() ) return;
        for( Iterator bIt = m.retrieveActiveBody().getUseAndDefBoxes().iterator(); bIt.hasNext(); ) {
            final ValueBox b = (ValueBox) bIt.next();
            Value v = b.getValue();
            if( !(v instanceof StaticFieldRef) ) continue;
            StaticFieldRef sfr = (StaticFieldRef) v;
            SootField f = sfr.getField();
            if( !f.getDeclaringClass().getName().equals( "java.lang.System" ) )
                continue;
            if( f.getName().equals( "err" ) ) {
                G.v().out.println( "Use of System.err in "+m );
            }
            if( f.getName().equals( "out" ) ) {
                G.v().out.println( "Use of System.out in "+m );
            }
        }
        for( Iterator sIt = m.getActiveBody().getUnits().iterator(); sIt.hasNext(); ) {
            final Stmt s = (Stmt) sIt.next();
            if( !s.containsInvokeExpr() ) continue;
            InvokeExpr ie = s.getInvokeExpr();
            SootMethod target = ie.getMethod();
            if( target.getDeclaringClass().getName().equals( "java.lang.System" )
                    && target.getName().equals( "exit" ) ) {
                warn( ""+m+" calls System.exit" );
            }
        }
        if( m.getName().equals( "<clinit>" ) ) {
            for( Iterator sIt = m.getActiveBody().getUnits().iterator(); sIt.hasNext(); ) {
                final Stmt s = (Stmt) sIt.next();
                for( Iterator bIt = s.getUseBoxes().iterator(); bIt.hasNext(); ) {
                    final ValueBox b = (ValueBox) bIt.next();
                    Value v = b.getValue();
                    if( v instanceof FieldRef ) {
                        warn( m.getName()+" reads field "+v );
                    }
                }
                if( !s.containsInvokeExpr() ) continue;
                InvokeExpr ie = s.getInvokeExpr();
                SootMethod target = ie.getMethod();
                calls( target );
            }
        }
    }
    private void calls( SootMethod target ) {
        if( target.getName().equals("<init>") ) {
            if( target.getDeclaringClass().getName().equals( "java.io.PrintStream" ) ) return;
            if( target.getDeclaringClass().getName().equals( "java.lang.Boolean" ) ) return;
            if( target.getDeclaringClass().getName().equals( "java.lang.Integer" ) ) return;
            if( target.getDeclaringClass().getName().equals( "java.lang.String" ) ) return;
            if( target.getDeclaringClass().getName().equals( "java.lang.Object" ) ) return;
        }
        if( target.getName().equals("getProperty") ) {
            if( target.getDeclaringClass().getName().equals( "java.lang.System" ) ) return;
        }
        if( target.getName().equals("charAt") ) {
            if( target.getDeclaringClass().getName().equals( "java.lang.String" ) ) return;
        }
        warn( "<clinit> invokes "+target );
    }
}