New Software Verification Methods Enhance C Language Modularity

Modularity, the division of software into functional units, has been a cornerstone of software development for half a century, particularly in the C language through compilation units and header files. However, effectively specifying and verifying these modular units to ensure correctness and reliability remains a significant challenge. This study addresses the knowledge gap in complementing programmatic modularity with robust specification and verification idioms for C, especially within the context of Verifiable C.

The developed techniques successfully enabled the formal verification of complex software units written in C, building upon principles established over half a century of software engineering. The implementation of abstract predicate declarations provided a robust framework for integrating existing verification principles, significantly enhancing modular reasoning capabilities. Residual predicates proved highly effective in enforcing data abstraction, particularly within callback-rich code, thereby bolstering software integrity and predictability. > The innovations allowed for the successful composition of fully linked verified programs using a novel, abstraction-respecting component composition rule for Verifiable C, a significant advancement since the study's publication in 2021. This approach effectively bridged the gap between low-level code verification and high-level model-level reasoning for object-oriented features.