Precise Goal-Independent Abstract Interpretation of Constraint Logic Programs

AbstractWe present a goal-independent abstract interpretation framework for pure constraint logic programs, and prove the sufficiency of a set of conditions for abstract domains to ensure that the analysis will never lose precision. Along the way, we formally define pure constraint logic programming systems, give a formal semantics that is independent of the actual constraint domain, and formally define the maximally precise abstraction of a pure constraint logic program

A program analysis framework for tccp based on abstract interpretation

[EN] The timed concurrent constraint language (tccp) is a timed extension of the concurrent constraint paradigm. tccp was defined to model reactive systems, where infinite behaviors arise naturally. In previous works, a semantic framework and abstract diagnosis method for the language have been defined. On the basis of that semantic framework, this paper proposes an abstract semantics that, together with a widening operator, is suitable for the definition of different analyses for tccp programs. The abstract semantics is correct and can be represented as a finite graph where each node represents a hypothetical (abstract) computational step of the program. The widening operator allows us to guarantee the convergence of the abstract fixpoint computation.This author has been supported by the Andalusian Excellence Project P11-TIC-7659. This work has been partially supported by the EU (FEDER) and the Spanish MINECO under grants TIN 2015-69175-C4-1-R and TIN 2013-45732-C4-1-P and by Generalitat Valenciana PROMETEOII/2015/013Comini, M.; Gallardo, M.; Titolo, L.; Villanueva, A. (2017). A program analysis framework for tccp based on abstract interpretation. Formal Aspects of Computing. 29(3):531-557. https://doi.org/10.1007/s00165-016-0409-8S531557293Alpuente M, Gallardo MM, Pimentel E, Villanueva A (2006) A semantic framework for the abstract model checking of tccp programs. Theor Comput Scie 346(1): 58–95Bagnara R, Hill PM., Ricci E, Zaffanella E (2005) Precise widening operators for convex polyhedra. Sci Comput Program 58(1–2):28–56Cousot P, Cousot R (1977) Abstract interpretation: a unified lattice model for static analysis of programs by construction or approximation of fixpoints. In: Proceedings of the 4th ACM SIGACT-SIGPLAN symposium on principles of programming languages, Los Angeles, California, January 17–19. ACM Press, New York, pp 238–252Clarke EM, Grumberg O, Jha S, Lu Y, Veith H (2000) Counterexample-guided abstraction refinement. In: CAV, Lecture Notes in Computer Science, vol 1855. Springer, pp 154–169Comini M, Gallardo MM, Titolo L, Villanueva A (2015) Abstract Analysis of Universal Properties for tccp. In: Falaschi M (ed) Logic-based Program Synthesis and Transformation, 25th International Symposium, LOPSTR 2015. Revised Selected Papers, Lecture Notes in Computer Science, vol 9527. Springer, pp 163–178Comini M, Titolo L, Villanueva A (2011) Abstract diagnosis for timed concurrent constraint programs. Theory Pract Logic Programm 11(4-5):487–502Comini M, Titolo L, Villanueva A (2013) A condensed goal-independent bottom-up fixpoint modeling the behavior of tccp. Technical report, DSIC, Universitat Politècnica de València. http://riunet.upv.es/handle/10251/34328de Boer FS, Gabbrielli M, Meo MC (2000) A timed concurrent constraint language. Inf Comput 161(1): 45–83Falaschi M, Gabbrielli M, Marriott K, Palamidessi C (1993) Compositional analysis for concurrent constraint programming. In: Proceedings of the eighth annual IEEE symposium on logic in computer science, Los Alamitos, CA, USA, IEEE Computer Society Press, pp 210–221Falaschi M, Olarte C, Palamidessi C (2015) Abstract interpretation of temporal concurrent constraint programs. Theory and Pract Logic Program (TPLP) 15(3): 312–357Falaschi M, Villanueva A (2006) Automatic verification of timed concurrent constraint programs. Theory Pract Logic Program 6(3): 265–300Gallardo MM, Merino P, Pimentel E (2002) Refinement of LTL formulas for abstract model checking. In: Static analysis, 9th international symposium, SAS 2002, Madrid, Spain, September 17–20, 2002, Proceedings, pp 395–410Saraswat VA (1993) Concurrent constraint programming. The MIT Press, CambridgeSaraswat VA, Rinard M, Panangaden P (1991) The semantic foundations of concurrent constraint programming. In: Proceedings of the 18th ACM SIGPLAN-SIGACT symposium on principles of programming languages. ACM, New York, pp 333–352Zaffanella E, Giacobazzi R, Levi G (1997) Abstracting synchronization in concurrent constraint programming. J Funct Logic Program (6

Modular Constraint Solver Cooperation via Abstract Interpretation

Cooperation among constraint solvers is difficult because different solving paradigms have different theoretical foundations. Recent works have shown that abstract interpretation can provide a unifying theory for various constraint solvers. In particular, it relies on abstract domains which capture constraint languages as ordered structures. The key insight of this paper is viewing cooperation schemes as abstract domains combinations. We propose a modular framework in which solvers and cooperation schemes can be seamlessly added and combined. This differs from existing approaches such as SMT where the cooperation scheme is usually fixed (e.g., Nelson-Oppen). We contribute to two new cooperation schemes: (i) interval propagators completion that allows abstract domains to exchange bound constraints, and (ii) delayed product which exchanges over-approximations of constraints between two abstract domains. Moreover, the delayed product is based on delayed goal of logic programming, and it shows that abstract domains can also capture control aspects of constraint solving. Finally, to achieve modularity, we propose the shared product to combine abstract domains and cooperation schemes. Our approach has been fully implemented, and we provide various examples on the flexible job shop scheduling problem. Under consideration for acceptance in TPLP.Comment: Paper presented at the 36th International Conference on Logic Programming (ICLP 2020), University Of Calabria, Rende (CS), Italy, September 2020, 17 pages. v2: Fix an example in Section 3.2 (improved closure

Experiments in abstract interpretation-based code certification for pervasive systems

Proof carrying code (PCC) is a general is originally a roof in ñrst-order logic of certain vermethodology for certifying that the execution of an un- ification onditions and the checking process involves trusted mobile code is safe. The baste idea is that the ensuring that the certifícate is indeed a valid ñrst-order code supplier attaches a certifícate to the mobile code proof. which the consumer checks in order to ensure that the The main practical difñculty of PCC techniques is in code is indeed safe. The potential benefit is that the generating safety certiñeates which at the same time: i) consumer's task is reduced from the level of proving to allow expressing interesting safety properties, ii) can be the level of checking. Recently, the abstract interpre- generated automatically and, iii) are easy and efficient tation techniques developed, in logic programming have to check. In [1], the abstract interpretation techniques been proposed as a basis for PCC. This extended ab- [5] developed in logic programming1 are proposed as stract reports on experiments which illustrate several is- a basis for PCC. They offer a number of advantages sues involved in abstract interpretation-based certifica- for dealing with the aforementioned issues. In particution. First, we describe the implementation of our sys- lar, the xpressiveness of existing abstract domains will tem in the context of CiaoPP: the preprocessor of the be implicitly available in abstract interpretation-based Ciao multi-paradigm programming system. Then, by code certification to deñne a wide range of safety propermeans of some experiments, we show how code certifi- ties. Furthermore, the approach inherits the automation catión is aided in the implementation of the framework. and inference power of the abstract interpretation en- Finally, we discuss the application of our method within gines used in (Constraint) Logic Programming, (C)LP. the área, of pervasive system

A practical approach to the global analysis of CLP programs

This paper presents and illustrates with an example a practical approach to the dataflow analysis of programs written in constraint logic programming (CLP) languages using abstract interpretation. It is first argued that, from the framework point of view, it sufnces to propose relatively simple extensions of traditional analysis methods which have already been proved useful and practical and for which efncient fixpoint algorithms have been developed. This is shown by proposing a simple but quite general extensión of Bruynooghe's traditional framework to the analysis of CLP programs. In this extensión constraints are viewed not as "suspended goals" but rather as new information in the store, following the traditional view of CLP. Using this approach, and as an example of its use, a complete, constraint system independent, abstract analysis is presented for approximating definiteness information. The analysis is in fact of quite general applicability. It has been implemented and used in the analysis of CLP(R) and Prolog-III applications. Results from the implementation of this analysis are also presented

Temporal reasoning in a logic programming language with modularity

Actualmente os Sistemas de Informação Organizacionais (SIO) lidam cada vez mais com informação que tem dependências temporais. Neste trabalho concebemos um ambiente de trabalho para construir e manter SIO Temporais. Este ambiente assenta sobre um linguagem lógica denominada Temporal Contextua) Logic Programming que integra modularidade com raciocínio temporal fazendo com que a utilização de um módulo dependa do tempo do contexto. Esta linguagem é a evolução de uma outra, também introduzida nesta tese, que combina Contextua) Logic Programming com Temporal Annotated Constraint Logic Programming, na qual a modularidade e o tempo são características ortogonais. Ambas as linguagens são formalmente discutidas e exemplificadas. As principais contribuições do trabalho descrito nesta tese incluem: • Optimização de Contextua) Logic Programming (CxLP) através de interpretação abstracta. • Sintaxe e semântica operacional para uma linguagem que combina de um modo independente as linguagens Temporal Annotated Constraint Logic Programming (TACLP) e CxLP. É apresentado um compilador para esta linguagem. • Linguagem (sintaxe e semântica) que integra de um modo inovador modularidade (CxLP) com raciocínio temporal (TACLP). Nesta linguagem a utilização de um dado módulo está dependente do tempo do contexto. É descrito um interpretador e um compilador para esta linguagem. • Ambiente de trabalho para construir e fazer a manutenção de SIO Temporais. Assenta sobre uma especificação revista da linguagem ISCO, adicionando classes e manipulação de dados temporais. É fornecido um compilador em que a linguagem resultante é a descrita no item anterior. ABSTRACT- Current Organisational Information Systems (OIS) deal with more and more Infor-mation that, is time dependent. In this work we provide a framework to construct and maintain Temporal OIS. This framework builds upon a logical language called Temporal Contextual. Logic Programming that deeply integrates modularity with tem-poral reasoning making the usage of a module time dependent. This language is an evolution of another one, also introduced in this thesis, that combines Contextual Logic Programming with Temporal Annotated Constraint Logic Programming where modularity and time are orthogonal features. Both languages are formally discussed and illustrated. The main contributions of the work described in this thesis include: • Optimisation of Contextual Logic Programming (CxLP) through abstract interpretation. • Syntax and operational semantics for an independent combination of the temporal framework Temporal Annotated Constraint Logic Programming (TACLP) and CxLP. A compiler for this language is also provided. • Language (syntax and semantics) that integrates in a innovative way modularity (CxLP) with temporal reasoning (TACLP). In this language the usage of a given module depends of the time of the context. An interpreter and a compiler for this language are described. • Framework to construct and maintain Temporal Organisational Information Systems. It builds upon a revised specification of the language ISCO, adding temporal classes and temporal data manipulation. A compiler targeting the language presented in the previous item is also given

Some considerations on the compile-time analysis of constraint logic programs

This paper discusses some issues which arise in the dataflow analysis of constraint logic programming (CLP) languages. The basic technique applied is that of abstract interpretation. First, some types of optimizations possible in a number of CLP systems (including efficient parallelization) are presented and the information that has to be obtained at compile-time in order to be able to implement such optimizations is considered. Two approaches are then proposed and discussed for obtaining this information for a CLP program: one based on an analysis of a CLP metainterpreter using standard Prolog analysis tools, and a second one based on direct analysis of the CLP program. For the second approach an abstract domain which approximates groundness (also referred to as "definiteness") information (i.e. constraint to a single valué) and the related abstraction functions are presented