Symbiotic-Witch: A Klee-Based Violation Witness Checker - (Competition Contribution)

Abstract

Abstract Symbiotic-Witch is a new tool for checking violation witnesses in the GraphML-based format used at SV-COMP since 2015. Roughly speaking, Symbiotic-Witch symbolically executes a given program with Klee and simultaneously tracks the set of nodes the witness automaton can be in. Moreover, it reads the return values of nondeterministic functions specified in the witness and uses them to prune the symbolic execution. The violation witness is confirmed if the symbolic execution reaches an error and the current set of witness nodes contains a matching violation node. Symbiotic-Witch currently supports violation witnesses of reachability safety, memory safety, memory cleanup, and overflow properties.