private void calculateGenKillSets(CFGBlock block, BlockDataFlowState bFlow) {
   for (int i = block.getStatements().size() - 1; i >= 0; i--) {
     LIRStatement stmt = block.getStatements().get(i);
     if (stmt.getClass().equals(QuadrupletStmt.class)) {
       QuadrupletStmt qStmt = (QuadrupletStmt) stmt;
       if (!qStmt.getDestination().getClass().equals(RegisterName.class)) {
         updateKillGenSet(block.getMethodName(), qStmt, bFlow);
       }
     } else if (stmt.getClass().equals(StoreStmt.class)) {
       updateKillGenSet(block.getMethodName(), (StoreStmt) stmt, bFlow);
     } else if (stmt.getClass().equals(CallStmt.class)) {
       updateKillGenSet(block.getMethodName(), (CallStmt) stmt, bFlow);
     }
   }
 }
  private BlockDataFlowState generateDFState(CFGBlock block) {
    int totalGlobals = this.uniqueGlobals.get(block.getMethodName()).size();

    // Get the original inBitSet for this block
    BitSet origIn;
    if (this.cfgBlocksState.containsKey(block)) {
      origIn = this.cfgBlocksState.get(block).getIn();
    } else {
      origIn = new BitSet(totalGlobals);
      origIn.set(0, totalGlobals);
    }

    // Calculate the in BitSet by taking intersection of predecessors
    BlockDataFlowState bFlow = new BlockDataFlowState(totalGlobals);

    // If there exist at least one successor, set Out to all True
    if (block.getSuccessors().size() > 0) {
      bFlow.getOut().set(0, totalGlobals);
    }

    BitSet out = bFlow.getOut();
    for (CFGBlock pred : block.getSuccessors()) {
      if (this.cfgBlocksState.containsKey(pred)) {
        out.and(this.cfgBlocksState.get(pred).getIn());
      }
    }

    calculateGenKillSets(block, bFlow);

    // Calculate Out
    BitSet in = bFlow.getIn(); // IN = (OUT - KILL) U GEN
    in.or(out);
    in.xor(bFlow.getKill());
    in.or(bFlow.getGen());

    if (!in.equals(origIn)) {
      // Add successors to cfgBlocks list
      for (CFGBlock pred : block.getPredecessors()) {
        if (!cfgBlocksToProcess.contains(pred)) {
          cfgBlocksToProcess.add(pred);
        }
      }
    }

    // Remove this block, since it has been processed
    cfgBlocksToProcess.remove(block);

    return bFlow;
  }