Value-passing CCS for Trees: A Theory for Concurrent Systems

TL;DR

This paper extends CCS for trees to include value-passing capabilities, introduces a nonsequential semantics, and demonstrates its application in modeling concurrent programming languages and relaxed memory models.

Contribution

It develops a new value-passing version of CCS for trees with a nonsequential semantics and applies it to formalize concurrent programming and memory models.

Findings

Defined weak barbed congruence and localized early weak bisimilarity.

Proposed semantics for a toy multi-threaded language.

Proved DRF-guarantee property for relaxed memory models.

Abstract

In this paper, we extend the theory CCS for trees (CCTS) to value-passing CCTS (VCCTS), of which symbols have the capacity for receiving and sending data values, and a nonsequential semantics is proposed in an operational approach. In this concurrent model, a weak barbed congruence and a localized early weak bisimilarity are defined, and the latter relation is proved to be sufficient to justify the former. As an illustration of potential applications of VCCTS, a semantics based on VCCTS is given to a toy multi-threaded programming language featuring a core of C/C++ concurrency; and a formalization based on the operational semantics of VCCTS is proposed for some relaxed memory models, and a DRF-guarantee property with respect to VCCTS is proved.