[abc-users] polyglot compiler exception while using abc to instrument aspect code

Dear all,
I found out the following problem using abc:
I am trying to instrument the compiled code in order to deduce basic
blocks coverage. To do this I read the soot tutorial to instrument class
files and I produced the following code:
I modified abc.main.AbcExtension adding to the method
addJimplePacks()these four code lines:

//added by me
Scene.v().addBasicClass("abc.aspectj.instrumentation.BlockTagger",SootClass.SIGNATURES);
//added by me
Scene.v().addBasicClass("java.io.PrintStream",SootClass.SIGNATURES);
//added by me
 Scene.v().addBasicClass("java.lang.System",SootClass.SIGNATURES);
PackManager.v().getPack("jtp").add(new Transform("jtp.uce",
UnreachableCodeEliminator.v()));
//added by me
PackManager.v().getPack("jtp").add(new
Transform("jtp.blockInstrumentation", new BlockInstrumenter()));

I built a BlockInstrumenter class which extends BodyTransformer and I
redefined internaltransform method:

protected void internalTransform(Body b, String arg1, Map arg2) {
       
        SootClass sc =
Scene.v().getSootClass("abc.aspectj.instrumentation.BlockTagger");
        SootMethod instrumenter = sc.getMethodByName("tagFirstUnitInBlock");
        BlockGraph bg = new CompleteBlockGraph(b);
        List<Block> blocksInGraph = bg.getBlocks();
        Chain units = b.getUnits();
        for(Block bl: blocksInGraph){
            Unit head = bl.getHead();
            InvokeExpr incExpr=
Jimple.v().newStaticInvokeExpr(instrumenter.makeRef());
            Stmt incStmt = Jimple.v().newInvokeStmt(incExpr);
            units.insertAfter(incStmt,head);
        }

Here is the code of the class I am trying to use for instrumentation.
This class has a static method that I would like to add a call to when a
basic block is entered.

public class BlockTagger {
   
    public static void tagFirstUnitInBlock(Unit u){
        ExecutedBlockTag t = new ExecutedBlockTag();
        ExecutedBlockTagAggregator ta = new ExecutedBlockTagAggregator();
        ta.considerTag(t, u);
    }

}

  ExecutedBlockTag() implements Tag and contains a boolean field.
ExecutedBlockTagAggregator() has an overridden method:
public void considerTag(Tag t, Unit u) {
        units.add(u);
        tags.add(t);
    }

When I run abc on my target program the compilation fails reporting the
following exception:

polyglot.util.InternalCompilerError: BoundPoint.aj:29,1-32:2: Error
during matching
    at
abc.weaving.matching.AdviceApplication.doShadows(AdviceApplication.java:208)
    at abc.main.AbcExtension.findMethodShadows(AbcExtension.java:508)
    at
abc.weaving.matching.AdviceApplication.doMethod(AdviceApplication.java:275)
    at
abc.weaving.matching.AdviceApplication.computeAdviceLists(AdviceApplication.java:312)
    at
abc.weaving.aspectinfo.GlobalAspectInfo.computeAdviceLists(GlobalAspectInfo.java:463)
    at analysis.aspectj.Main.preprocess(Main.java:381)
    at analysis.aspectj.Main.main(Main.java:91)
Caused by: java.lang.NullPointerException
    at abc.weaving.residues.CheckType.construct(CheckType.java:62)
    at abc.weaving.residues.Bind.construct(Bind.java:89)
    at abc.weaving.aspectinfo.ArgVar.matchesAt(ArgVar.java:53)
    at abc.weaving.aspectinfo.Args.matchesAt(Args.java:134)
    at abc.weaving.aspectinfo.AndPointcut.matchesAt(AndPointcut.java:68)
    at
abc.weaving.matching.AdviceApplication$2.run(AdviceApplication.java:114)
    at
abc.weaving.matching.AdviceApplication.doShadows(AdviceApplication.java:191)
    ... 6 more
polyglot.util.InternalCompilerError: BoundPoint.aj:29,1-32:2: Error
during matching
    at
abc.weaving.matching.AdviceApplication.doShadows(AdviceApplication.java:208)
    at abc.main.AbcExtension.findMethodShadows(AbcExtension.java:508)
    at
abc.weaving.matching.AdviceApplication.doMethod(AdviceApplication.java:275)
    at
abc.weaving.matching.AdviceApplication.computeAdviceLists(AdviceApplication.java:312)
    at
abc.weaving.aspectinfo.GlobalAspectInfo.computeAdviceLists(GlobalAspectInfo.java:463)
    at analysis.aspectj.Main.preprocess(Main.java:381)
    at analysis.aspectj.Main.main(Main.java:91)
Caused by: java.lang.NullPointerException
    at abc.weaving.residues.CheckType.construct(CheckType.java:62)
    at abc.weaving.residues.Bind.construct(Bind.java:89)
    at abc.weaving.aspectinfo.ArgVar.matchesAt(ArgVar.java:53)
    at abc.weaving.aspectinfo.Args.matchesAt(Args.java:134)
    at abc.weaving.aspectinfo.AndPointcut.matchesAt(AndPointcut.java:68)
    at
abc.weaving.matching.AdviceApplication$2.run(AdviceApplication.java:114)
    at
abc.weaving.matching.AdviceApplication.doShadows(AdviceApplication.java:191)
    ... 6 more

does anyone have any suggestion that can help me?
thanks in advance
Luca

-- 
Luca Cavallaro
Ph.D. student
DEI, Politecnico di Milano,
Via Golgi 40
200133 Milan,
Italy
/------------------------------------------------------------/
Aphasia is the loss of speech in computer scientists when asked:
   "But of what use is your research?"