Interprocedural register allocation for the WAM based on source-to-source transformations

An approach for interprocedural register allocation for the WAM is presented which is based on source-to-source transformations of an intermediary language called Continuation Prolog. Continuation Prolog fills the conceptual gap between Prolog source code and the underlying abstract machine. Our approach does not require an analysis of the whole program. Only the definition of a predicate must be analyzed, but not its use. For certain kinds of predicates like DCGs no analysis is required at all. An implementation of our approach has been integrated into the WAM code generation of SICStus- Prolog. Our approach yields speedups up to 30% for existing benchmarks.