2012 | OriginalPaper | Chapter
Language-Theoretic Abstraction Refinement
Authors : Zhenyue Long, Georgel Calin, Rupak Majumdar, Roland Meyer
Published in: Fundamental Approaches to Software Engineering
Publisher: Springer Berlin Heidelberg
Activate our intelligent search to find suitable subject content or patents.
Select sections of text to find matching patents with Artificial Intelligence. powered by
Select sections of text to find additional relevant content using AI-assisted search. powered by
We give a language-theoretic counterexample-guided abstraction refinement (CEGAR) algorithm for the safety verification of recursive multi-threaded programs. First, we reduce safety verification to the (undecidable) language emptiness problem for the intersection of context-free languages. Initially, our CEGAR procedure overapproximates the intersection by a context-free language. If the overapproximation is empty, we declare the system safe. Otherwise, we compute a bounded language from the overapproximation and check emptiness for the intersection of the context free languages and the bounded language (which is decidable). If the intersection is non-empty, we report a bug. If empty, we refine the overapproximation by removing the bounded language and try again. The key idea of the CEGAR loop is the language-theoretic view: different strategies to get regular overapproximations and bounded approximations of the intersection give different implementations. We give concrete algorithms to approximate context-free languages using regular languages and to generate bounded languages representing a family of counterexamples. We have implemented our algorithms and provide an experimental comparison on various choices for the regular overapproximation and the bounded underapproximation.