Dependency analysis tools: reusable components for software maintenance

A general-purpose toolset that is being developed to capture and analyze software dependencies is described. The tools are designed to serve as reusable components. They can be used not only to aid programmers directly in understanding programs but also as a basis from which other specialized tools can be constructed. The tools use the concept of a dependency graph as a basic abstraction to simplify the understanding of software relationships. Definitional, calling, functional and data-flow dependencies are analyzed. An external dependency graph for each function is developed to encapsulate the effects of function cells