A practical and flexible flow analysis for higher-order languages

Abstract

A flow analysis collects data-flow and control-flow information about programs. A compiler can use this information to enable optimizations. The analysis described in this article unifies and extends previous work on flow analysis for higher-order languages supporting assignment and control operators. The analysis is abstract interpretation based and is parameterized over two polyvariance operators and a projection operator. These operators are used to regulate the speed and accuracy of the analysis. An implementation of the analysis is incorporated into and used in a production Scheme compiler. The analysis can process any legal Scheme program without modification. Others have demonstrated that a 0CFA analysis can enables the optimizations, but a 0CFA analysis is O ( n ) 3 ). An O ( n ) instantiation of our analysis successfully enables the optimization of closure representations and procedure calls. Experiments with the cheaper instantiation show that it is as effective as 0CFA for these optimizations.