Scheduling Constraint Based Abstraction Refinement for Weak Memory Models

Abstract

Scheduling constraint based abstraction refinement (SCAR) is one of the most efficient methods for verifying programs under sequential consistency (SC). However, most multi-processor architectures implement weak memory models (WMMs) in order to improve the performance of a program. Due to the nondeterministic execution of those memory operations by the same thread, the behavior of a program under WMMs is much more complex than that under SC, which significantly increases the verification complexity. This paper elegantly extends the SCAR method to WMMs such as TSO and PSO. To capture the order requirements of an abstraction counterexample under WMMs, we have enriched the event order graph (EOG) of a counterexample such that it is competent for both SC and WMMs. We have also proposed a unified EOG generation method which can always obtain a minimal EOG efficiently. Experimental results on a large set of multi-threaded C programs show promising results of our method. It significantly outperforms state-of-the-art tools, and the time and memory it required to verify a program under TSO and PSO are roughly comparable to that under SC.