Author:

Keywords:

partial evaluation, partial deduction, program specialisation, compiler generation, abstract interpretation, binding-time analysis, logic programs, partial evaluator, termination analysis, compilation, mercury, tool, Science & Technology, Technology, Computer Science, Software Engineering, Computer Science, Theory & Methods, Logic, Computer Science, Science & Technology - Other Topics, BINDING-TIME ANALYSIS, PARTIAL DEDUCTION, PARTIAL EVALUATOR, TERMINATION ANALYSIS, cs.PL, cs.AI, D.1.6; D.1.2; I.2.2; F.4.1; I.2.3, 0801 Artificial Intelligence and Image Processing, 0802 Computation Theory and Mathematics, 0803 Computer Software, Computation Theory & Mathematics, 4602 Artificial intelligence, 4613 Theory of computation

Abstract:

The so called "cogen approach" to program specialisation, writing a compiler generator instead of a specialiser, has been used with considerable success in partial evaluation of both functional and imperative languages. This paper demonstrates that the cogen approach is also applicable to the specialisation of logic programs (called partial deduction) and leads to effective specialisers. Moreover, using good binding-time annotations, the speed-ups of the specialised programs are comparable to the speed-ups obtained with online specialisers. The paper first develops a generic approach to offline partial deduction and then a specific offline partial deduction method, leading to the offline system LIX for pure logic programs. While this is a usable specialiser by itself, it is used to develop the cogen System LOGEN. Given a program, a specification of what inputs will be static, and an annotation specifying which calls should be unfolded, LOGEN generates a specialised specialiser for the program at hand. Running this specialiser with particular values for the static inputs results in the specialised program. While this requires two steps instead of one, the efficiency of the specialisation process is improved in situations where the same program is specialised multiple times. The paper also presents and evaluates an automatic binding-time analysis that is able to derive the annotations. While the derived annotations are still suboptimal compared to hand-crafted ones, they enable nonexpert users to use the LOGEN system in a fully automated way. Finally, LOGEN is extended so as to directly support a large part of Prolog's declarative and non-declarative features and so as to be able to perform so called mixline specialisations.