Towards certified compilation of RTFM-core applications

Abstract

Concurrent programming is dominated by thread based solutions with lock based critical sections. Careful attention has to be paid to avoid race and deadlock conditions. Real-Time for The Masses (RTFM) takes an alternative language approach, introducing tasks and named critical sections (via resources) natively in the RTFM-core language. RTFM-core programs can be compiled to native C-code, and efficiently executed onto single-core platforms under the Stack Resource Policy (SRP) by the RTFM-kernel. In this paper we formally define the well-formedness criteria for SRP based resource management, and develop a certified (formally proven) implementation of the corresponding compilation from nested critical sections of the input RTFM-core program to a resulting flat sequence of primitive operations and scheduling primitives. Moreover we formalise the properties for resource ceilings under SRP and develop a certified algorithm for their computation. The feasibility of the described approach is shown through the adoption of the Why3 platform, which allows the necessary verification conditions to be automatically generated and discharged through a variety of automatic external SMT-solvers and interactive theorem provers. Moreover, Why3 supports the extraction of certified Ocaml code for proven implementations in WhyML. As a proof of concept the certified extracted development is demonstrated on an example system.