Parallel Refinement for Multi-Threaded Program Verification

Program verification is one of the most important methods to ensuring the correctness of concurrent programs. However, due to the path explosion problem, concurrent program verification is usually time consuming, which hinders its scalability to industrial programs. Parallel processing is a mainstream technique to deal with those problems which require mass computing. Hence, designing parallel algorithms to improve the performance of concurrent program verification is highly desired. This paper focuses on parallelization of the abstraction refinement technique, one of the most efficient techniques for concurrent program verification. We present a parallel refinement framework which employs multiple engines to refine the abstraction in parallel. Different from existing work which parallelizes the search process, our method achieves the effect of parallelization by refinement constraint and learnt clause sharing, so that the number of required iterations can be significantly reduced. We have implemented this framework on the scheduling constraint based abstraction refinement method, one of the best methods for concurrent program verification. Experiments on SV-COMP 2018 show the encouraging results of our method. For those complex programs requiring a large number of iterations, our method can obtain a linear reduction of the iteration number and significantly improve the verification performance.