Lists are ubiquitous in functional programs, thus supporting lists efficiently is a major concern to compiler writers for functional languages. Lists are normally represented as linked cons cells, with each cons cell containing a car (the data) and a cdr (the link); this is inefficient in the use of space, because 50% of the storage is used for links. Loops and recursions on lists are slow on modern machines because of the long chains of control dependences (in checking for nil) and data dependences (in fetching cdr fields). We present a data structure for "unrolled lists," where each cell has several data items (car fields) and one link (cdr). This reduces the memory used for links, and it significantly shortens the length of control-dependence and data-dependence chains in operations on lists. We further present an efficient compile-time analysis that transforms programs written for "ordinary" lists into programs on unrolled lists. The use of our new representation requires no change...

Many language theoreticians have taken great efforts in designing higher-level programming languages that are more elegant and more expressive than conventional languages. However, few of these new languages have been implemented very efficiently. The result is that most software engineers still prefer to use conventional languages, even though the new higherlevel languages offer a better and simpler programming model. This dissertation concentrates on improving the performance of programs written in Standard ML (SML)---a statically typed functional language---on today's RISC machines. SML poses tough challenges to efficient implementations: very frequent function calls, polymorphic types, recursive data structures, higher-order functions, and first-class continuations. This dissertation presents the design and evaluation of several new compilation techniques that meet these challenges by taking advantage of some of the higher-level language features in SML. Type-directed compilation ...

This paper introduces a new data structure, the VList, that is compact, thread safe and significantly faster to use than Linked Lists for nearly all list operations. Space usage can be reduced by 50% to 90% and in typical list operations speed improved by factors ranging from 4 to 20 or more. Some important operations such as indexing and length are typically changed from O(N) to O(1) and O(lgN) respectively. A language interpreter Visp, using a dialect of Common Lisp, has been implemented using VLists and the benchmark comparison with OCAML reported. It is also shown how to adapt the structure to create variable length arrays, persistent deques and functional hash tables. The VArray requires no resize copying and has an average O(1) random access time. Comparisons are made with previous resizable one dimensional arrays, Hash Array Trees (HAT) Sitarski [1996], and Brodnik, Carlsson, Demaine, Munro, and Sedgewick [1999]