BDD-Based Software Model Checking with CPAchecker

In symbolic software model checking, most approaches use predicates as symbolic representation of the state space, and SMT solvers for computations on the state space; BDDs are sometimes used as auxiliary data structure. The representation of software state spaces by BDDs was not yet thoroughly investigated, although BDDs are successful in hardware verification. The reason for this is that BDDs do not efficiently support all operations that are needed in software verification. In this work, we evaluate the use of a pure BDD representation of integer variable values, and focus on a particular class of programs: event-conditionaction systems with limited operations. A symbolic representation using BDDs seems appropriate for this particular class of programs. We implement a program analysis based on BDDs and experimentally compare three symbolic techniques to verify reachability properties of ECA programs. The results show that BDDs are efficient, which yields the insight that BDDs could be used selectively for some variables (to be determined by a pre-analysis), even in general software model checking.