@Override
    public void visitCallInstruction(CallInstruction instruction, int offset, int nextOffset) {
      visitInstruction(instruction, offset, nextOffset);
      for (int i = instruction.procBegin; i <= instruction.procEnd; i++) {
        readVariables[i] = null;
      }
    }
@Override
    public void visitCallInstruction(CallInstruction instruction, int offset, int nextOffset)