Systematic formal verification of interpreters

Formal methods have gained acceptance in the hardware field through a pragmatic approach that has succeeded in providing systematic, scalable, highly automated, and cost effective treatments for certain stereotypical problems of practical importance. By identifying stereotypical problems, the effort required to develop effective formal methods has been amortized over many applications. We suggest that formal methods can achieve similar industrial success in selected software applications by following the same principles. As an illustration, we examine approaches to the stereotypical problem of interpreter correctness in the presence of timing differences between the specification and implementation interpreters. In hardware, this corresponds to the problem of verifying microprogrammed, pipelined, or superscalar processors, but it has wider applications to any system-hardware or software-that can be considered as an interpreter.