Work

Compositional Semantics for Shared-Variable Concurrency

Year: 2024

Type: article

Abstract: We revisit the fundamental problem of defining a compositional semantics for a concurrent programming language under sequentially consistent memory with the aim of equating the denotations of pieces of code if and only if these pieces induce the same behavior under all program contexts. While the denotational semantics presented by Brookes [Information and Computation 127, 2 (1996)] has been considered a definitive solution, we observe that Brookes’s full abstraction result crucially relies on the availability of an impractical whole-memory atomic read-modify-write instruction. In contrast, we consider a language with standard primitives, which apply to a single variable. For that language, we propose an alternative denotational semantics based on traces that track program write actions together with the writes expected from the environment, and equipped with several closure operators to achieve necessary abstraction. We establish the adequacy of the semantics, and demonstrate full abstraction for the case that the analyzed code segment is loop-free. Furthermore, we show that by including a whole-memory atomic read in the language, one obtains full abstraction for programs with loops. To gain confidence, our results are fully mechanized in Coq.

Source: Proceedings of the ACM on Programming Languages

DOI: 10.1145/3656399

Authors: Mikhail Svyatlovskiy, Shai Mermelstein, Ori Lahav

Institution: Tel Aviv University

Language: English

Topic: Logic, programming, and type systems

Subfield: Software

Field: Computer Science

Domain: Physical Sciences

Open Access status: diamond

Funders: Israel Science Foundation, European Research Council

Awards: G2929751576, G4244396775