We propose a denotational semantics for the two-level language of [GJ91, Gom92], and prove its correctness w.r.t. a standard denotational semantics. Other researchers (see [Gom91, GJ91, Gom92, JGS93, HM94]) have claimed correctness for lambda-mix (or extensions of it) based on denotational models, but the proofs of such claims rely on imprecise definitions and are basically awed. At a technical level there are two important differences between our model and more naive models in Cpo: the domain for interpreting dynamic expressions is more abstract (we interpret code as -terms modulo -conversion), the semantics of newname is handled differently (we exploit functor categories). The key idea is to interpret a two-level language in a suitable functor category Cpo D op rather than Cpo. The semantics of newname follows the ideas pioneered by Oles and Reynolds for modeling the stack discipline of Algol-like languages. Indeed, we can think of the objects of D (i.e. the natural numbers) as ...

. We show that compiler optimisations based on strictness analysis can be expressed formally in the functional framework using continuations. This formal presentation has two benefits: it allows us to give a rigorous correctness proof of the optimised compiler; and it exposes the various optimisations made possible by a strictness analysis. 1 Introduction Realistic compilers for imperative or functional languages include a number of optimisations based on non-trivial global analyses. Proving the correctness of such optimising compilers can be done in three steps: 1. proving the correctness of the original (unoptimised) compiler; 2. proving the correctness of the analysis; and 3. proving the correctness of the modifications of the simple-minded compiler to exploit the results of the analysis. A substantial amount of work has been devoted to steps (1) and (2) but there have been surprisingly few attempts at tackling step (3). In this paper we show how to carry out this third step in the...

We show that compiler optimisations based on strictness analysis can be expressed formally in the functional framework using continuations. This formal presentation has two benefits: it allows us to give a rigorous correctness proof of the optimised compiler; and it exposes the various optimisations made possible by a strictness analysis. These benefits are especially significant in the presence of partially evaluated data structures. 1 Introduction Realistic compilers for imperative or functional languages include a number of optimisations based on non-trivial global analyses. Proving the correctness of such optimising compilers should involve three steps: 1. proving the correctness of the original (unoptimised) compiler; 2. proving the correctness of the analysis; and 3. proving the correctness of the modifications of the simple-minded compiler to exploit the results of the analysis. A substantial amount of work has been devoted to steps (1) and (2) but there has been surprisingly ...