Automated Compositional Abstraction Re nement for Concurrent C Programs : A Two - Level Approach 1

The state space explosion problem in model checking remains the chief obstacle to the practical veri cation of real-world distributed systems. We attempt to address this problem in the context of verifying concurrent (message-passing) C programs against safety speci cations. More speci cally, we present a fully automated compositional framework which combines two orthogonal abstraction techniques (operating respectively on data and events) within a counterexample-guided abstraction re nement (CEGAR) scheme. In this way, our algorithm incrementally increases the granularity of the abstractions until the speci cation is either established or refuted. Our explicit use of compositionality delays the onset of state space explosion for as long as possible. To our knowledge, this is the rst compositional use of CEGAR in the context of model checking concurrent C programs. We describe our approach in detail, and report on some very encouraging preliminary experimental results obtained with our tool MAGIC.