Symbolic Analysis of Maude Theories with Narval

[EN] Concurrent functional languages that are endowed with symbolic reasoning capabilities such as Maude offer a high-level, elegant, and efficient approach to programming and analyzing complex, highly nondeterministic software systems. Maude's symbolic capabilities are based on equational unification and narrowing in rewrite theories, and provide Maude with advanced logic programming capabilities such as unification modulo user-definable equational theories and symbolic reachability analysis in rewrite theories. Intricate computing problems may be effectively and naturally solved in Maude thanks to the synergy of these recently developed symbolic capabilities and classical Maude features, such as: (i) rich type structures with sorts (types), subsorts, and overloading; (ii) equational rewriting modulo various combinations of axioms such as associativity, commutativity, and identity; and (iii) classical reachability analysis in rewrite theories. However, the combination of all of these features may hinder the understanding of Maude symbolic computations for non-experienced developers. The purpose of this article is to describe how programming and analysis of Maude rewrite theories can be made easier by providing a sophisticated graphical tool called Narval that supports the fine-grained inspection of Maude symbolic computations.This work has been partially supported by the EU (FEDER) and the Spanish MCIU under grant RTI2018-094403-B-C32, by the Spanish Generalitat Valenciana under grants PROMETEO/2019/098 and APOSTD/2019/127, and by the US Air Force Office of Scientific Research under award number FA9550-17-1-0286.Alpuente Frasnedo, M.; Escobar Román, S.; Sapiña-Sanchis, J.; Ballis, D. (2019). Symbolic Analysis of Maude Theories with Narval. Theory and Practice of Logic Programming. 19(5-6):874-890. https://doi.org/10.1017/S1471068419000243S874890195-

TOOLympics 2019: An Overview of Competitions in Formal Methods

Evaluation of scientific contributions can be done in many different ways. For the various research communities working on the verification of systems (software, hardware, or the underlying involved mechanisms), it is important to bring together the community and to compare the state of the art, in order to identify progress of and new challenges in the research area. Competitions are a suitable way to do that. The first verification competition was created in 1992 (SAT competition), shortly followed by the CASC competition in 1996. Since the year 2000, the number of dedicated verification competitions is steadily increasing. Many of these events now happen regularly, gathering researchers that would like to understand how well their research prototypes work in practice. Scientific results have to be reproducible, and powerful computers are becoming cheaper and cheaper, thus, these competitions are becoming an important means for advancing research in verification technology. TOOLympics 2019 is an event to celebrate the achievements of the various competitions, and to understand their commonalities and differences. This volume is dedicated to the presentation of the 16 competitions that joined TOOLympics as part of the celebration of the 25th anniversary of the TACAS conference

Formal Design of Cloud Computing Systems in Maude

Cloud computing systems are complex distributed systems whose design is challenging for two main reasons: (1) since they are distributed systems, a correct design is very hard to achieve by testing alone; and (2) cloud computing applications have high availability and performance requirements; but these are hard to measure before implementation and hard to compare between different implementations. This paper summarizes our experience in using formal specification in Maude and model checking analysis to quickly explore the design space of a cloud computing system to achieve a high quality design that: (1) has verified correctness guarantees; (2) has better performance properties than other design alternatives so explored; (3) can be achieved before an actual implementation; and (4) can be used for both rapid prototyping and for automatic code generation.Ope

Dagstuhl News January - December 2011

"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic

Tools and Algorithms for the Construction and Analysis of Systems

This open access two-volume set constitutes the proceedings of the 27th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2021, which was held during March 27 – April 1, 2021, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2021. The conference was planned to take place in Luxembourg and changed to an online format due to the COVID-19 pandemic. The total of 41 full papers presented in the proceedings was carefully reviewed and selected from 141 submissions. The volume also contains 7 tool papers; 6 Tool Demo papers, 9 SV-Comp Competition Papers. The papers are organized in topical sections as follows: Part I: Game Theory; SMT Verification; Probabilities; Timed Systems; Neural Networks; Analysis of Network Communication. Part II: Verification Techniques (not SMT); Case Studies; Proof Generation/Validation; Tool Papers; Tool Demo Papers; SV-Comp Tool Competition Papers

Programming Languages and Systems

This open access book constitutes the proceedings of the 28th European Symposium on Programming, ESOP 2019, which took place in Prague, Czech Republic, in April 2019, held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2019

Automated Black Box Generation of Structured Inputs for Use in Software Testing

A common problem in automated software testing is the need to generate many inputs with complex structure in a black-box fashion. For example, a library for manipulating red-black trees may require that inputs are themselves valid red-black trees, meaning anything invalid is not suitable for testing. As another example, in order to test code generation in a compiler, it is necessary to use input programs which are both syntactically valid and well-typed. Despite the importance of this problem, we observe that existing solutions are few in number and have severe drawbacks, including unreasonably slow performance and a lack of generality to testing different systems.This thesis presents a solution to this problem of black-box structured input generation. I observe that test inputs can be described as solutions to systems of logical constraints, and that more expressive constraints can lead to more complex tests. In order to test effectively and generate many tests, we need high-performance constraint solvers capable of finding many solutions to these constraints. I observe that constraint logic programming (CLP) offers an expressive constraint language paired with a high-performance constraint solver, and thus serves as a potential solution to this problem. Via a series of case studies, I have found that CLP (1) is applicable to testing a wide variety of systems; (2) can scale to more complex constraints than ever previously described; and (3) is often orders of magnitude faster than competing solutions. These case studies have also exposed dozens of bugs in high-profile software, including the Rust compiler and the Z3 SMT solver