Systematic design of static program analyzers

Static program analyzers (SPA) are interactive tools that enhance program understanding by answering queries about programs. An SPA parses source programs and builds a so-called program knowledge base (PKB) that enables automatic processing of program queries. An SPA design method described in this paper consists of steps during which we (1) identify, a class of program queries we wish to answer, (2) model program information that is required to resolve queries, (3) define physical representation for programs, based on the concept of a hybrid PKB, and (4) implement other SPA components such as a front-end and user interface. Generally, queries related to global properties of programs are best handled if we store program information in a relational database. On the other hand, detailed queries are best supported if we represent programs as attributed syntax trees. A hybrid PKB described in this paper integrates these two program representations. Our notation for specifying a hybrid PKB forms a basis for a generation system that automates some of the routine, but time consuming, tasks involved in implementation of programming tools