🤖 AI Summary
In logical reasoning about concurrent programs, expression and condition reuse is semantically unsafe due to interference from shared variables.
Method: This paper introduces the first algebraic formalization of the rely-guarantee framework, constructing an algebraic semantic model that supports precise expression evaluation semantics; it systematically characterizes necessary and sufficient conditions for safe expression reuse.
Contribution/Results: The work fills a foundational gap in Hoare logic—namely, the lack of a sound theoretical basis for reasoning about expression evaluation under concurrent interference. It derives novel, verifiable inference rules that extend standard concurrent program logics, ensuring both formal rigor and automation friendliness. By enabling sound and modular reuse of expressions and conditions across concurrent contexts, the approach significantly enhances the reliability, reusability, and automated verifiability of logical reasoning for concurrent programs.
📝 Abstract
Hoare-style inference rules for program constructs permit the copying of expressions and tests from program text into logical contexts. It is known that this requires care even for sequential programs but further issues arise for concurrent programs because of potential interference to the values of variables. The"rely-guarantee"approach does tackle the issue of recording acceptable interference and offers a way to provide safe inference rules. This paper shows how the algebraic presentation of rely-guarantee ideas can clarify and formalise the conditions for safely re-using expressions and tests from program text in logical contexts for reasoning about programs.