A Type System for the Automatic Distribution of Higher-order Synchronous Dataflow Programs

International audienceWe address the design of distributed systems with synchronous dataflow programming languages. As modular design entails handling both architectural and functional modularity, our first contribution is to extend an existing synchronous dataflow programming language with primitives allowing the description of a distributed architecture and the localization of some expressions onto some processors. We also present a distributed semantics to formalize the distributed execution of synchronous programs. Our second contribution is to provide a type system, in order to infer the localization of non-annotated values by means of type inference and to ensure, at compilation time, the consistency of the distribution. Our third contribution is to provide a type-directed projection operation to obtain automatically,from a centralized typed program, the local program to be executed by each computing resource. The type system as well as the automatic distribution mechanism has been fully implemented in the compiler of an existing synchronous data-flow programming language

Multi-threaded code generation from Signal program to OpenMP

International audienceThe use of multi-core processors will become a trend in safety critical systems. For safe execution of multithreaded code, automatic code generation from formal specification is a desirable method. Signal, a synchronous language dedicated for the functional description of safety critical systems, provides soundness semantics for deterministic concurrency. Although sequential code generation of Signal has been implemented in Polychrony compiler, deterministic multi-threaded code generation strategy is still far from mature. Moreover, existing code generation methods use certain multi-thread library, which limits the cross platform executions. OpenMP is an application program interface (API) standard for parallel programming, supported by several mainstream compilers from different platforms. This paper presents a methodology translating Signal program to OpenMP-based multi-threaded C code. First, the intermediate representation of the core syntax of Signal using synchronous guarded actions is defined. Then, according to the compositional semantics of Signal equations, the Signal program is synthesized to dependency graph (DG). After parallel tasks are extracted from dependency graph, the Signal program can be finally translated into OpenMP-based C code which can be executed on multiple platforms

Compilation of polychronous data flow equations

Chapter 1, on the "Compilation of Polychronous Data-Flow Equations", gives a thorough presentation of the program analysis and code generation techniques present in Polychrony, a compiler for the data-flow synchronous language Signal. Introduced in the late 1980s, Signal and its polychronous model of computation stand among the most developed concepts of synchronous programming. It allows to model concurrent embedded software architectures using high-level multi-clocked synchronous data-flow equations. The chapter defines the formal methodology consisting of all required program analysis and transformation techniques to automatically generate the sequential or concurrent code suiting the targer architecture (embedded or distributed) or compilation goals (modularity or performance)