A Practical String Analyzer by the Widening Approach

Abstract. The static determination of approximated values of string expressions has many potential applications. For instance, approximated string values may be used to check the validity and security of generated strings, as well as to collect the useful string properties. Previous string analysis efforts have been focused primarily on the maxmization of the precision of regular approximations of strings. These methods have not been completely satisfactory due to the difficulties in dealing with heap variables and context sensitivity. In this paper, we present an abstract-interpretation-based solution that employs a heuristic widening method. The presented solution is implemented and compared to JSA. In most cases, our solution gives results as precise as those produced by previ-ous methods, and it makes the additional contribution of easily dealing with heap variables and context sensitivity in a very natural way. We anticipate the employment of our method in practical applications.

ASTEC -- the Aarhus STellar Evolution Code

The Aarhus code is the result of a long development, starting in 1974, and still ongoing. A novel feature is the integration of the computation of adiabatic oscillations for specified models as part of the code. It offers substantial flexibility in terms of microphysics and has been carefully tested for the computation of solar models. However, considerable development is still required in the treatment of nuclear reactions, diffusion and convective mixing.Comment: Astrophys. Space Sci, in the pres

Shape Analysis in the Absence of Pointers and Structure

discover properties of dynamic and/or mutable structures. We ask, “Is there an equivalent to shape analysis for purely functional programs, and if so, what ‘shapes ’ does it discover? ” By treating binding environments as dynamically allocated structures, by treating bindings as addresses, and by treating value environments as heaps, we argue that we can analyze the “shape ” of higher-order functions. To demonstrate this, we enrich an abstract-interpretive control-flow analysis with principles from shape analysis. In particular, we promote “anodization ” as a way to generalize both singleton abstraction and the notion of focusing, and we promote “binding invariants ” as the analog of shape predicates. Our analysis enables two optimizations known to be beyond the reach of control-flow analysis (globalization and super-β inlining) and one previously unknown optimization (higher-order rematerialization).