A Non-Intrusive Approach for Measuring Data and Control Coupling b/w Software Components: Addressing the Challenges of DO-178C Compliance, Verification and Certification 2024-26-0464

Software certification guidelines, such as RTCA DO-178C, mandate the analysis of data and control coupling (DC/CC) in safety-critical avionics software using requirement-based testing. The intention of this analysis is to ensure correctness in the interactions and dependencies between software components. The shift from confirming the coupling (as in DO-178B) to verifying the exercising of the coupling (as introduced in DO-178C) transitions the DC/CC objective from an analytical exercise against the test design to a measurement exercise against the test execution. Current methodologies for measuring Data Coupling and Control Coupling (DC/CC) rely on source code instrumentation, which embeds code to record coverage information during requirements-based testing. However, this approach has significant drawbacks. Primarily, it necessitates executing tests on both the instrumented and non-instrumented versions of the code, ensuring their outputs match. This not only increases testing costs and time but also presents performance issues as the inserted instrumentation expands code size, potentially consuming more memory and extending execution time. Often, the instrumented code is so large it surpasses memory limitations, leading to the creation and maintenance of numerous partially instrumented code builds, further complicating the testing process and inflating testing costs. This paper proposes a novel, non-intrusive, and highly efficient method for measuring and reporting data and control coupling (DC/CC) information derived from the execution of requirements-based tests. The proposed method extracts the expected DC/CC information from the software architecture and design, and the actual DC/CC information from program execution and data trace information during test execution, all without source code instrumentation. This addresses all the challenges present in existing solutions.