The Apron Numerical Abstract Domain Library
Participants : Antoine Miné [ correspondent ] , Bertrand Jeannet [ team PopArt, INRIA-RA ] .
The Apron library is dedicated to the static analysis of the numerical variables of a program by abstract interpretation. Its goal is threefold: provide ready-to-use numerical abstractions under a common API for analysis implementers, encourage the research in numerical abstract domains by providing a platform for integration and comparison of domains, and provide a teaching and demonstration tool to disseminate knowledge on abstract interpretation.
The Apron library is not tied to a particular numerical abstraction but instead provides several domains with various precision versus cost trade-offs (including intervals, octagons, linear equalities and polyhedra). A specific C API was designed for domain developers to minimize the effort when incorporating a new abstract domain: only few domain-specific functions need to be implemented while the library provides various generic services and fallback methods (such as scalar and interval operations for most numerical data-types, parametric reduced products, and generic transfer functions for non-linear assignments). For the analysis designer, the Apron library exposes a higher-level API with C, C++, and OCaml bindings. This API is domain-neutral and supports a rich set of semantic operations, including parallel assignments (useful to analyze automata), substitutions (useful for backward analysis), non-linear numerical expressions, and IEEE floating-point arithmetic.
The Apron library is freely available on the web at http://apron.cri.ensmp.fr/library/ under the LGPL license. Packages exist for the Debian and Fedora Linux distributions. In order to help disseminate the knowledge on abstract interpretation, a simple inter-procedural static analyzer for a toy language is included. An on-line version is deployed at http://pop-art.inrialpes.fr/interproc/interprocweb.cgi .
The Apron library is developed since 2006 and currently consists of 86 000 lines of C, C++, and OCaml. This year has seen the release of version 0.9.10, which mainly includes bugfixes and minor improvements in the API and build system. We also published a tool paper  describing the library and its design philosophy.
Current external library users include the Proval/Démon team (LRI Orsay, France), the Analysis of Computer Systems Group (New-York University, USA), the Sierum software analysis platform (Kansas State University, USA), NEC Labs (Princeton, USA), EADS CCR (Paris, France), IRIT (Toulouse, France), ONERA (Toulouse, France), CEA LIST (Saclay, France), VERIMAG (Grenoble, France), ENSMP CRI (Fontainebleau, France), the IBM T.J. Watson Research Center (USA), the University of Edinburgh (UK).