Zooid: a DSL for certified multiparty computation: from mechanised metatheory to certified multiparty processes

We design and implement Zooid, a domain specific language for certified multiparty communication, embedded in Coq and implemented atop our mechanisation framework of asynchronous multiparty session types (the first of its kind). Zooid provides a fully mechanised metatheory for the semantics of global and local types, and a fully verified end-point process language that faithfully reflects the type-level behaviours and thus inherits the global types properties such as deadlock freedom, protocol compliance, and liveness guarantees

A Dependently-Typed Linear π -Calculus in Agda

Session types have consolidated as a formalism for the specification and static enforcement of communication protocols. Many different theories of dependent session types have been proposed, some enabling refined specifications on the content of messages, others allowing the structure of the protocols to depend on data exchanged in the protocol itself. In this work we continue a line of research studying the foundations of binary session types. In particular, we propose a variant of the linear π-calculus whose type structure encompasses virtually all dependent session types using just two type constructors: linear channel types and linear dependent pairs. We use Agda not only to formalize the metatheory of the calculus and obtain machine-checked proofs of type soundness, but also as host language in which we implement data-dependent protocols

Zooid: A DSL for Certified Multiparty Computation

We design and implement Zooid, a domain specific language for certified multiparty communication, embedded in Coq and implemented atop our mechanisation framework of asynchronous multiparty session types (the first of its kind). Zooid provides a fully mechanised metatheory forthe semantics of global and local types, and a fully verified end-point process language that faithfully reflects the type-level behaviours and thus inherits the global types properties such as deadlock freedom, protocol compliance, and liveness guarantees

Comparing type systems for deadlock freedom

Message-passing software systems exhibit non-trivial forms of concurrency and distribution; they are expected to follow intended protocols among communicating services, but also to never “get stuck”. This intuitive requirement has been expressed by liveness properties such as progress or (dead)lock freedom and various type systems ensure these properties for concurrent processes. Unfortunately, very little is known about the precise relationship between these type systems and the classes of typed processes they induce. This paper puts forward the first comparative study of different type systems for message-passing processes that guarantee deadlock freedom. We compare two classes of deadlock-free typed processes, here denoted L and K. The class L stands out for its canonicity: it results from Curry-Howard interpretations of classical linear logic propositions as session types. The class K, obtained by encoding session types into Kobayashi’s linear types with usages, includes processes not typable in other type systems. We show that L is strictly included in K, and identify the precise conditions under which they coincide. We also provide two type-preserving translations of processes in K into processes in L

Bounded Verification of Message-Passing Concurrency in Go

Go is a programming language that has gained increased popularity due to its good support for system programming and its channel-based message passing concurrency mechanism. These features rendered Go the language of choice of many platform software developers. Go offers a wide range of primitives to coordinate lightweight threads, e.g., channels, waitgroups, and mutexes. Although, these concurrency primitives help mitigate data races, they introduce additional complications due to the complexity of reasoning about concurrency. In this thesis, we first perform an empirical analysis on concurrent Go programs which analyses 125 Go projects from GitHub in order to understand how concurrency is used in publicly available code. Our results include the following findings: (1) concurrency primitives are used frequently and intensively, (2) most projects use synchronous communication channels over asynchronous ones, and (3) most Go projects use simple concurrent thread topologies, which are however currently not fully supported by existing static verification frameworks. To address these limitations, we propose a novel static checker for Go programs that relies on performing bounded model checking of their concurrent behaviours. In contrast to previous works, our approach deals with large codebases, supports programs that have statically unknown parameters and is extensible to additional concurrency primitives. Our work includes an empirical analysis that studies the usage of concurrency in Go projects, a detailed presentation of the extraction algorithm from Go programs to Promela models, an algorithm to automatically check programs with statically unknown parameters, and a large scale evaluation of our approach. The latter shows that our approach outperforms the state-of-the-art

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 25th International Conference on Fundamental Approaches to Software Engineering, FASE 2022, which was held during April 4-5, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 17 regular papers presented in this volume were carefully reviewed and selected from 64 submissions. The proceedings also contain 3 contributions from the Test-Comp Competition. The papers deal with the foundations on which software engineering is built, including topics like software engineering as an engineering discipline, requirements engineering, software architectures, software quality, model-driven development, software processes, software evolution, AI-based software engineering, and the specification, design, and implementation of particular classes of systems, such as (self-)adaptive, collaborative, AI, embedded, distributed, mobile, pervasive, cyber-physical, or service-oriented applications

Verification of Concurrent Systems : optimality, Scalability and Applicability

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, leída el 14-10-2020Tanto el testing como la verificacion de sistemas concurrentes requieren explorar todos los posibles entrelazados no deterministas que la ejecucion concurrente puede tener, ya que cualquiera de estos entrelazados podra revelar un comportamiento erroneo del sistema. Esto introduce una explosion combinatoria en el numero de estados del programa que deben ser considerados, lo que frecuentemente lleva a un problema computacionalmente intratable. El objetivo de esta tesis es el desarrollo de tecnicas novedosas para el testing y la verificacion de programas concurrentes que permitan reducir esta explosion combinatoria...Both verification and testing of concurrent systems require exploring all possible non-deterministic interleavings that the concurrent execution may have, as any of the interleavings may reveal an erroneous behavior of the system. This introduces a combinatorial explosion on the number of program states that must be considered, what leads often to a computationally intractable problem. The overall goal of this thesis is to investigate novel techniques for testing and verification of concurrent programs that reduce this combinatorial explosion...Fac. de InformáticaTRUEunpu

Tools and Algorithms for the Construction and Analysis of Systems

This open access two-volume set constitutes the proceedings of the 26th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The total of 60 regular papers presented in these volumes was carefully reviewed and selected from 155 submissions. The papers are organized in topical sections as follows: Part I: Program verification; SAT and SMT; Timed and Dynamical Systems; Verifying Concurrent Systems; Probabilistic Systems; Model Checking and Reachability; and Timed and Probabilistic Systems. Part II: Bisimulation; Verification and Efficiency; Logic and Proof; Tools and Case Studies; Games and Automata; and SV-COMP 2020