A Parallel On-Demand Algorithm for Computing Interprocedural Dominators

Abstract

We present a new algorithm for computing interprocedural dominators. The algorithm identifies a set of special nodes, which are the only ones that can have interprocedural dominance edges, and extends the intraprocedural dominator trees by deriving those edges. The computation of the dominators of each node is independent of the computation of any other node, and therefore can be done on demand for each node as required. For the same reason, the algorithm lends itself naturally to parallelization. The algorithm has been implemented, and is shown to be practical for large programs. Because of its cooperative caching behavior, the algorithm gains a large performance boost when running on parallel hardware. We also present an efficient way of extending the algorithm for computing interprocedural dominance frontiers and control dependence.