Abstract

Control flow analysis (cfa) is now well known but is not widely used in real compilers since optimizations that can be achieved via cfa are not so clear. This paper aims at showing that control flow analysis is very valuable in practice by presenting a fundamental optimization based on cfa: the closure representation algorithm, the essential optimizing phase of a -language compiler. Since naive and regular scheme to represent functions as heap allocated structures is far too inefficient, the main effort of modern functional languages compilers is devoted to minimize the amount of memory allocated for functions. In particular, compilers try to discover when a procedure can safely be handled without any allocation at all. Previously described methods to do so are ad hoc, depending on the language compiled, and not very precise. Using cfa, we present a general approach which produces better results. This refined closure analysis subsumes previously known ones and optimizes more than 80 % ...

Citations