Evaluating inlining techniques

For efficiency and ease of implementation, many compilers implicitly impose an “inlining policy” to restrict the conditions under which a procedure may be inlined. An inlining technique consists of an inlining policy and a strategy for choosing a sequence of inlining operations that is consistent with the policy. The effectiveness of an inlining technique is affected by the restrictiveness of the inlining policy as well as the effectiveness of the (heuristic) inlining strategy. The focus of this paper is on the comparison of inlining policies and techniques, and the notions of power and flexibility are introduced. As a major case study, we identify and compare policies based on the version of the inlined procedure that is used.