Counterexample Guided Abstraction Refinement of product-line behavioural models

The model-checking problem for Software Products Lines (SPLs) is harder than for single systems: variability constitutes a new source of complexity that exacerbates the state-explosion problem. Abstraction techniques have successfully alleviated state explosion in single-system models. However, they need to be adapted to SPLs, to take into account the set of variants that produce a counterexample. In this paper, we apply CEGAR (Counterexample-Guided Abstraction Refinement) and we design new forms of abstraction specifically for SPLs. We carry out experiments to evaluate the efficiency of our new abstractions. The results show that our abstractions, combined with an appropriate refinement strategy, hold the potential to achieve large reductions in verification time, although they sometimes perform worse. We discuss in which cases a given abstraction should be used.