public FaintVariableAnalysis(Body body) {

    Chain<Local> locals = body.getLocals();

    allVariables = new CollectionFlowUniverse<Local>(locals);

    universalSet = new ArrayPackedSet(allVariables);

    for (Local l : locals) universalSet.add(l);

    useSetMap = new HashMap<Unit, BoundedFlowSet>();
    defSetMap = new HashMap<Unit, BoundedFlowSet>();

    UnitGraph graph = new BriefUnitGraph(body);
    for (Unit u : graph) {

      BoundedFlowSet defSet = new ArrayPackedSet(allVariables);
      BoundedFlowSet useSet = new ArrayPackedSet(allVariables);

      for (ValueBox v : u.getDefBoxes()) {
        // Only do this for locals. We're not going to even try to handle anything
        // other than locals.
        if (v.getValue() instanceof Local) {
          defSet.add(v.getValue());
        }
      }
      for (ValueBox v : u.getUseBoxes()) {
        // Only do this for locals. We're not going to even try to handle anything
        // other than locals.
        if (v.getValue() instanceof Local) {
          useSet.add(v.getValue());
        }
      }

      defSetMap.put(u, defSet);
      useSetMap.put(u, useSet);
    }
  }