Enhanced Sharing Analysis Techniques: A Comprehensive Evaluation

Roberto Bagnara, Enea Zaffanella and Patricia M. Hill

To appear at the 2nd International Conference on Principles and Practice of Declarative Programming (PPDP 2000), Montreal, Canada, September 20-22, 2000


Sharing, a domain due to Jacobs and Langen for the analysis of logic programs, derives useful aliasing information. It is well-known that a commonly used core of techniques, such as the standard integration of Sharing with freeness and linearity information, can significantly improve the precision of Sharing. However, a number of other proposals for refined domain combinations have been circulating for years. One feature that is common to these proposals is that they do not seem to have undergone experimental evaluation even with respect to the expected precision gains. In this paper, we discuss and/or experimentally evaluate: helping Sharing with definitely ground variables computed with Pos; the incorporation of explicit structural information into the domain of analysis; more sophisticated ways of integrating Sharing and Pos; the issue of reordering the bindings in the computation of the abstract mgu; an original proposal concerning the addition of a domain recording the set of variables that are deemed to be ground or free; a more refined way of using linearity to improve the analysis; the issue of whether tracking compoundness allows to compute more precise sharing information; and, finally, the recovery of hidden information in the combination of Sharing with the usual domain for freeness.