Analysis of synchronisation patterns in stateful active objects

This paper presents a static analysis technique based on effect and behavioural types for deriving synchronisation patterns of stateful active objects and verifying their safety – e.g. absence of deadlocks. This is challenging because active objects use futures to refer to results of pending asynchronous invocations and because these futures can be stored in object fields, passed as method parameters, or returned by invocations. Our effect system traces the access to object fields, thus allowing us to compute behavioural types that express synchronisation patterns in a precise way. The behavioural types are thereafter analysed by a solver that discovers potential deadlocks. Key-words : Deadlock detection, type system, behavioral types, stateful active objects 1. Laboratoire I3S – CNRS – [email protected] 2. INRIA, University of Bologna [email protected] 3. Laboratoire I3S – Université Côte d’Azur, INRIA – [email protected] Analysis of synchronisations in stateful active objects Ludovic Henrio, Cosimo Laneve, and Vincenzo Mastandrea 1 Université Côte d’Azur, CNRS, I3S, France, [email protected] 2 University of Bologna, Italy & INRIA-Focus, France, [email protected] 3 Université Côte d’Azur, CNRS, I3S, INRIA-Focus, France, [email protected] Abstract. This paper presents a static analysis technique based on effect and behavioural types for deriving synchronisation patterns of stateful active objects and verifying their safety – e.g. absence of deadlocks. This is challenging because active objects use futures to refer to results of pending asynchronous invocations and because these futures can be stored in object fields, passed as method parameters, or returned by invocations. Our effect system traces the access to object fields, thus allowing us to compute behavioural types that express synchronisation patterns in a precise way. The behavioural types are thereafter analysed by a solver that discovers potential deadlocks. This paper presents a static analysis technique based on effect and behavioural types for deriving synchronisation patterns of stateful active objects and verifying their safety – e.g. absence of deadlocks. This is challenging because active objects use futures to refer to results of pending asynchronous invocations and because these futures can be stored in object fields, passed as method parameters, or returned by invocations. Our effect system traces the access to object fields, thus allowing us to compute behavioural types that express synchronisation patterns in a precise way. The behavioural types are thereafter analysed by a solver that discovers potential deadlocks.