Using Mathematics to Improve Ada Compiled Code

Abstract

We have developed two mathematical techniques which, used together, can increase the speed of Ada compiled code, in two ways. We can eliminate most subprogram call overhead, involving stack pointer adjustment when a subprogram is called and when it returns. We can also eliminate most static scoping overhead, requiring the use of multiple base registers when procedures are nested. In particular, all this overhead can be eliminated in the absence of recursion. One of our techniques is based on an analogy with a variant of the well-known critical path method. The other is based on a new result in directed graph theory, which has many potential applications in addition to the one presented here.