Dependency analysis of Ada programs

1. ABSTRACT The working hypothesis of this paper has been the belief that Software Testing and Analysis (STA) methods should be integrated around a common conceptual framework. An analysis of two potential candidates for such a framework, Program Dependencies and Information Flow relations, shows that the ideal framework should posses the mathematical elegance of the flow relations and the generality of program dependencies. However, program dependencies have originally been formulated for compiler optimization and their uncritical use in software engineering is lacking. Therefore, modifications to the original dependencies have been proposed in this paper. They include partial vs. total definitions of Ada arrays, new concept of reaching definitions, potential Vs guaranteed dependencies, interprocedural dependencies, and an explanation feature that helps the user understand the reasons for the generated reports. It has been shown how the modified model can support descriptive and proscriptive (e.g. anomalies) queries about the program and, due to the clear separation of control flow from data flow and the lack of language restrictions, they are potentially applicable to a wider class of STA methods, including dynamic (execution-based) analysis. Also, Path Analysis, a novel method for the identification of dependencies along individual program paths has been proposed. It has been shown that path analysis offers a more accurate model for procedure calls, allows one to detect otherwise undetectable data flow anomalies and can serve as a vehicle for the analysis of error creation and propagation in testing and debugging.