Automated Workarounds from Java Program Specifications based on SAT Solving

The failures that bugs in software lead to can sometimes be bypassed by the so-called workarounds: when a (faulty) routine fails, alternative routines that the system offers can be used in place of the failing one, to circumvent the failure. Existing approaches to workaround-based system recovery consider workarounds that are produced from equivalent method sequences, automatically computed from user-provided abstract models, or directly produced from user-provided equivalent sequences of operations. In this paper, we present two techniques for computing workarounds from Java code equipped with formal specifications, that improve previous approaches in two respects. First, the particular state where the failure originated is actively involved in computing workarounds, thus leading to repairs that are more state specific. Second, our techniques automatically compute workarounds on concrete program state characterizations, avoiding abstract software models and user-provided equivalences. The first technique uses SAT solving to compute a sequence of methods that is equivalent to a failing method on a specific failing state, but which can also be generalized to schemas for workaround reuse. The second technique directly exploits SAT to circumvent a failing method, building a state that mimics the (correct) behaviour of a failing routine, from a specific program state too. We perform an experimental evaluation based on case studies involving implementations of collections and a library for date arithmetic, showing that the techniques can effectively compute workarounds from complex contracts in an important number of cases, in time that makes them feasible to be used for run-time repairs. Our results also show that our state-specific workarounds enable us to produce repairs in many cases where previous workaround-based approaches are inapplicable.Fil: Uva, Marcelo Ariel. Universidad Nacional de Río Cuarto; ArgentinaFil: Ponzio, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Regis, Germán. Universidad Nacional de Río Cuarto; ArgentinaFil: Aguirre, Nazareno Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Frias, Marcelo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Instituto Tecnológico de Buenos Aires; Argentin

The DynAlloy Visualizer

We present an extension to the DynAlloy tool to navigate DynAlloy counterexamples: the DynAlloy Visualizer. The user interface mimics the functionality of a programming language debugger. Without this tool, a DynAlloy user is forced to deal with the internals of the Alloy intermediate representation in order to debug a flaw in her model.Comment: In Proceedings LAFM 2013, arXiv:1401.056

Towards scaling up DynAlloy analysis using predicate abstraction

DynAlloy is an extension to the Alloy specifi cation language suitable for modeling properties of executions of software systems. DynAlloy provides fully automated support for verifying properties of programs, in the style of the Alloy Analyzer, i.e., by exhaustively searching for counterexamples of properties in bounded scenarios (bounded domains and iterations of programs). But, as for other automated analysis techniques, the so called state explotion problem makes the analysis feasible only for small bounds. In this paper, we take advantage of an abstraction technique known as predicate abstraction, for scaling up the analysis of DynAlloy specifi cations. The implementation of predicate abstraction we present enables us to substantially increase the domain and iteration bounds in some case studies, and its use is fully automated. Our implementation is relatively e cient, exploiting the reuse of already calculated abstractions when these are available, and an "on the fly" check of traces when looking for counterexamples. We introduce the implementation of the technique, and some preliminary experimental results with case studies, to illustrate the benefi ts of the technique.VI Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

Translating between Alloy specifications and UML class diagrams annotated with OCL

Model-driven engineering (MDE) is a software engineering approach based on model transformations at different abstraction levels. It prescribes the development of software by successively transforming the models from abstract (specifications) to more concrete ones (code). Alloy is an increasingly popular lightweight formal specification language that supports automatic verification. Unfortunately, its widespread industrial adoption is hampered by the lack of an ecosystem of MDE tools, namely code generators. This paper presents a model transformation from Alloy to UML class diagrams annotated with OCL (UML+OCL) and shows how an existing transformation from UML+OCL to Alloy can be improved to handle dynamic issues. The proposed bidirectional transformation enables a smooth integration of Alloy in the current MDE contexts, by allowing UML+OCL specifications to be transformed to Alloy for validation and verification, to correct and possibly refine them inside Alloy, and to translate them back to UML+OCL for sharing with stakeholders or to reuse current model-driven architecture tools to refine them toward code.This work was funded by European Regional Development Fund (ERDF) through the COMPETE Programme (operational program for competitiveness) and by national funds through the FCT (Fundaaco para a Ciencia e a Tecnologia-portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-020532. Part of the work was done while the first author was visiting the Software Design Group at CSAIL, MIT, USA, funded by FCT sabbatical grant SFRH/BSAB/1187/2011. The second author was also partially supported by QREN (the portuguese National Strategy Reference Chart) project 1621, while visiting the High-Assurance Software Laboratory at Universidade do Minho, Portugal. Finally, we would also like to thank all anonymous reviewers for the valuable comments and suggestions

Reparación de programas aplicando templates: generando workarounds permanentes a través de SAT

La aplicación de procesos modernos y sistemáticos en el desarrollo de sistemas informáticos con estrictos estándares de calidad no ha podido evitar la presencia de defectos en el software. A pesar de extensas test-suites, un alto porcentaje de sistemas son implantados con fallas. El desarrollo de técnicas de reparación de programas ha cobrado gran importancia en esta última década. El concepto de workaround ha sido utilizado por diversos enfoques para la reparación de programas. Un workaround aprovecha la redundancia implícita en un sistema con el propósito de evitar fallas detectadas en runtime. A partir de una técnica de cómputo automático de state-bound workarounds (workarounds dependientes de estado) que utiliza SAT-Solving, se propone un procedimiento de búsqueda de workaround templates independientes de estado, es decir, state-free workarounds que permitan mejorar los tiempos de reparación de programas.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Reparación de programas aplicando templates: generando workarounds permanentes a través de SAT

La aplicación de procesos modernos y sistemáticos en el desarrollo de sistemas informáticos con estrictos estándares de calidad no ha podido evitar la presencia de defectos en el software. A pesar de extensas test-suites, un alto porcentaje de sistemas son implantados con fallas. El desarrollo de técnicas de reparación de programas ha cobrado gran importancia en esta última década. El concepto de workaround ha sido utilizado por diversos enfoques para la reparación de programas. Un workaround aprovecha la redundancia implícita en un sistema con el propósito de evitar fallas detectadas en runtime. A partir de una técnica de cómputo automático de state-bound workarounds (workarounds dependientes de estado) que utiliza SAT-Solving, se propone un procedimiento de búsqueda de workaround templates independientes de estado, es decir, state-free workarounds que permitan mejorar los tiempos de reparación de programas.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Reparación de programas aplicando templates: generando workarounds permanentes a través de SAT

La aplicación de procesos modernos y sistemáticos en el desarrollo de sistemas informáticos con estrictos estándares de calidad no ha podido evitar la presencia de defectos en el software. A pesar de extensas test-suites, un alto porcentaje de sistemas son implantados con fallas. El desarrollo de técnicas de reparación de programas ha cobrado gran importancia en esta última década. El concepto de workaround ha sido utilizado por diversos enfoques para la reparación de programas. Un workaround aprovecha la redundancia implícita en un sistema con el propósito de evitar fallas detectadas en runtime. A partir de una técnica de cómputo automático de state-bound workarounds (workarounds dependientes de estado) que utiliza SAT-Solving, se propone un procedimiento de búsqueda de workaround templates independientes de estado, es decir, state-free workarounds que permitan mejorar los tiempos de reparación de programas.XVI Workshop Ingeniería de Software.Red de Universidades con Carreras en Informátic

Towards scaling up DynAlloy analysis using predicate abstraction

DynAlloy is an extension to the Alloy specifi cation language suitable for modeling properties of executions of software systems. DynAlloy provides fully automated support for verifying properties of programs, in the style of the Alloy Analyzer, i.e., by exhaustively searching for counterexamples of properties in bounded scenarios (bounded domains and iterations of programs). But, as for other automated analysis techniques, the so called state explotion problem makes the analysis feasible only for small bounds. In this paper, we take advantage of an abstraction technique known as predicate abstraction, for scaling up the analysis of DynAlloy specifi cations. The implementation of predicate abstraction we present enables us to substantially increase the domain and iteration bounds in some case studies, and its use is fully automated. Our implementation is relatively e cient, exploiting the reuse of already calculated abstractions when these are available, and an "on the fly" check of traces when looking for counterexamples. We introduce the implementation of the technique, and some preliminary experimental results with case studies, to illustrate the benefi ts of the technique.VI Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI