Extracting State Diagrams from Legacy Systems

A basic problem of reverse engineering is to understand legacy systems and derive abstract characterizations of poorly documented software. In the case of objectoriented software, the static structure (e.g. inheritance and association relationships) can usually be understood easily, and it can be extracted from existing software using automated tools. This is due to the fact that the static aspects of object-oriented programs are well known and more or less explicitly indicated in the source. Understanding and characterizing the dynamic behavior of such systems, in contrast, is usually much more difficult because of the gap between the static source text and the run-time behavior of the resulting executable program. However, the dynamic behavior of a program is equally important as its static specification for understanding the software. Dynamic characterization is particularly important for those parts of a system which are mainly understood by their dynamic behavior, like various kinds of controllers, drivers etc.