Moral dominance relations for program comprehension

Dominance trees have been used as a means for reengineering legacy systems into potential reuse candidates. The dominance relation suggests the reuse candidates which are identified by strongly directly dominated subtrees. We review the approach and illustrate how the dominance tree may fail to show the relationship between the strongly directly dominated procedures and the directly dominated procedures. We introduce a relation of generalized conditional independence which strengthens the argument for the adoption of the potential reuse candidates suggested by the dominance tree and explains their relationship with the directly dominated vertices. This leads to an improved dominance tree, the moral dominance tree, which helps aid program comprehension available from the tree. The generalized conditional independence relation also identifies potential reuse candidates that are missed by the dominance relation.