Custom static analysis to enhance insight into the usage of in-house libraries

Abstract

For software maintenance and evolution, insight into the codebase is crucial. One way to enhance insight is the application of static analysis to extract and visualize program-specific relations from the code itself, such as call graphs and inheritance trees. Yet, software often contains in-house libraries: unique, domain-specific libraries whose usage is typically scattered throughout the codebase. To provide sufficient insight into the usage of those libraries, the static analysis must be customized with domain-specific information. In this paper, we propose a method to enhance insight into the usage of in-house libraries by producing custom overviews. Furthermore, we describe three exploratory case studies targeting industrial C++ and Ada codebases, in which the method was developed, evolved, and validated. The method prescribes how to create custom overviews using static analysis iteratively, starting from a user-provided, initial specification of proper library usage using code patterns. As a safeguard, the method includes cross-checks to detect code fragments that deviate from proper library usage. Whenever such a deviating library usage is found, the code owners determine whether that deviating library usage should be added to the specification of proper library usage or the code fragment should be made compliant. The latter alternative makes both the codebase more regular and keeps the custom static analysis simpler. The method creates custom overviews that reveal opportunities to improve the usage of the in-house libraries, e.g., the removal of domain-specific redundant code which cannot be detected using generic tools, such as compilers and linters.We observed that industrial codebases are regular enough to create custom overviews using static analysis in the three exploratory case studies. Furthermore, we observed that the cross-checks, which detect deviating library usage, ensure the validity and completeness of the custom overviews. We conclude that producing custom overviews for in-house libraries using the method is valuable and feasible.