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Backward analysis via over-approximate abstraction and under-approximate subtraction
conference contribution
posted on 2014-06-26, 14:09 authored by Nir Piterman, Alexey Bakhirkin, Josh BerdineWe propose a novel approach for computing weakest liberal safe preconditions of programs. The standard approaches, which call for either under-approximation of a greatest fixed point, or complementation of a least fixed point, are often difficult to apply successfully. Our approach relies on a different decomposition of the weakest precondition of loops. We exchange the greatest fixed point for the computation of a least fixed point above a recurrent set, instead of the bottom element. Convergence is achieved using over-approximation, while in order to maintain soundness we use an under-approximating logical subtraction operation. Unlike general complementation, subtraction more easily allows for increased precision in case its arguments are related. The approach is not restricted to a specific abstract domain and we use it to analyze programs using the abstract domains of intervals and of 3-valued structures.
History
Citation
Lecture Notes in Computer ScienceAuthor affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Computer ScienceSource
21st International Static Analysis Symposium, Munich GermanyVersion
- AM (Accepted Manuscript)