Sagar Chaki

Sagar Chaki, Edmund Clarke, Natasha Sharygina, Nishant Sinha, Formal Methods in System Design (FMSD), volume 32, number 3, page 235-266, June 2008.

Abstract: This paper presents an automated and compositional procedure to solve the substitutability problem in the context of evolving software systems. Our solution contributes two techniques for checking correctness of software upgrades: 1) a technique based on simultaneous use of over- and under- approximations obtained via existential and universal abstractions; 2) a dynamic assume-guarantee reasoning algorithm -- previously generated component assumptions are reused and altered on-the-fly to prove or disprove the global safety properties on the updated system. When upgrades are found to be non-substitutable, our solution generates constructive feedback to developers showing how to improve the components. The substitutability approach has been implemented and validated in the ComFoRT reasoning framework, and we report encouraging results on an industrial benchmark.