使用事件自动机规约的C语言有界模型检测∗

摘要

In this paper, a technology is presented to use event automata to specify the safety properties of C programs and apply bounded model checking to verify whether a C program satisfies an event automaton property. An event automaton can specify a safety property which is based on the events generated by a program. It can also specify a property with infinite states. Since an event automaton separates from C programs, it will not change the structures of programs. The paper introduces the definition of an automaton reachability tree based on an event automaton. It then uses automaton reachability trees and the bounded model checking to build the SMT (satisfiability modulo theory) models of event automata and C programs. Finally, it supplies the SMT models to an SMT solver. An algorithm for generating counterexamples is obtained according to the results of the solver. The case studies and experimental results demonstrate that the presented approach can verify the event properties of software systems.%提出使用事件自动机对 C 程序的安全属性进行规约，并给出了基于有界模型检测的形式化验证方法。事件自动机可以规约程序中基于事件的安全属性，且可以描述无限状态的安全属性。事件自动机将属性规约与C程序本身隔离，不会改变程序的结构。在事件自动机的基础上，提出了自动机可达树的概念。结合自动机可达树和有界模型检测技术，给出将事件自动机和C程序转化为可满足性模理论SMT(satisfiability modulo theory)模型的算法。最后，使用SMT求解器对生成的SMT模型求解，并根据求解结果给出反例路径分析算法。实例分析和实验结果表明，该方法可以有效验证软件系统中针对事件的属性规约。