Abstract: The paper presents an interval temporal logic—CFITL(control flow interval temporal logic) which is used to specify the temporal properties of abstract model of program, for example control flow graph, generally abbreviated to CFG. The targeted logic differs from the general sense of temporal logics, typically CTL and LTL, whose semantical models are defined in term of the state-based structures. The semantics of CFITL is defined on an ordered CFG structure, which encodes the static structure and dynamic behavior of program. The ordered CFGs are a subset of CFGs, and their topology can be summarized by partially ordered sets, such that the induced natural number intervals can be mapped onto the well-formed structures of program. In other words, the CFITL formulae have the ability of specifying the properties related to not only the dynamic behavior but also static structure of programs. After the syntax and semantics of CFITL are expounded, the problem of model checking over CFITL is detailedly discussed. Furthermore, two types of algorithms are designed: one is based on the computation of reachable state space as well as the another is based on bounded model checking employing the SMT(satisfiability modulo theories) solvers power. Because programs implemented by advanced programming languages inevitably involve complex abstract data types with unbounded domains and operators, and the semantics of CFITL is more complex than the one of CTL, the method of SMT based model checking is more practical than the method of direct search of state space. In the sequel, a prototype tool is implemented, and some case studies are conducted.

Key words: interval temporal logic, control flow graph (CFG), static structure of program, model checking, satisfiability modulo theories (SMT)