Automatic extraction of executable program subsets by simultaneous dynamic program slicing

Abstract

Developers of software product families and maintainers of “legacy” software can benefit from the ability to automatically extract a correctly functioning subset of the code of a system that performs a desired subset of its behaviors. This article introduces a technique for automatic subsetting based on computing asimultaneous dynamic program slice of the code for a set of representative inputs. I show first why the naive approach (unioning traditional dynamic slices) fails, then give an abstract algorithm that succeeds in any slicing framework satisfying certain (mild) assumptions. Experiments using an implementation within the ISAT environment indicate that the algorithm consistently produces significantly smaller subsets than three competing approaches. I also discuss how to characterize the subset's correctness on inputs of interest outside the set used to compute the slice.