Tail all elimination on the Java

URL: http://www.elsevier.nl/locate/entcs/volume59.html 14 pages Tail all elimination on the Java Virtual Ma hine Mi hel S hinz 1 Martin Odersky 2 É ole Polyte hnique Fédérale de Lausanne Abstra t A problem that often has to be solved by ompilers for fun tional languages targeting the Java Virtual Ma hine is the elimination of tail alls. This paper explains how we solved it in our Funnel ompiler and presents some experimental results about the impa t our te hnique has on both performan e and size of the ompiled programs. 1 Introdu tion A problem fa ed by authors of ompilers for fun tional languages targeting the Java Virtual Ma hine (JVM) [7℄ is the elimination of tail alls. Fun tional programming languages typi ally do not have expli it looping onstru ts, and programmers therefore have to resort to re ursion to perform loops. While this is no major problem for programmers, ompiler writers have to make sure that their implementations perform tail all elimination, an optimisation whi h guarantees that loops implemented using re ursion exe ute in onstant spa e. Implementing tail all elimination in its full generality typi ally requires some support from the target ma hine. Unfortunately, the JVM does not provide su h support, and implementors either have to abandon general tail all elimination, or use spe ial tri ks. We have implemented general tail all elimination for our Funnel ompiler. This paper explains the te hnique we used, and shows its impa t on ode size and exe ution time for several ben hmark programs. It is stru tured in the following way: Se tion 2 explains why tail all elimination is needed, espeially in the urrent version of Funnel; Se tion 3 presents known te hniques to eliminate tail alls, then our te hnique and some experimental results about it; Se tion 4 presents related work; nally, Se tion 5 on ludes and talks about future work.