A unified interprocedural program representation for a maintenance environment

Unified interprocedural graph (UIG) that extracts the important features of existing program representations and adds new information to provide an integrated representation for maintenance tasks is presented. Algorithms that were developed for previous representations are adapted to use the UIG by identifying the subset of nodes and edges in the UIG required for that computation. Newly developed algorithms can use the UIG since it contains data flow, control flow, data dependence, and control dependence information. The main benefits of this approach are the reduction in storage space since individual representations are not kept, the savings in maintenance time of a single representation over the individual representations, and the convenience of accessing a single program representation without increase in access time. A single program representation also assists in program understanding since relationships among program elements are incorporated into one graph