Synthesising Interprocedural Bit-Precise Termination Proofs (extended version)
This addresses the need for scalable termination proofs to prevent issues like hanging programs and denial-of-service attacks, representing an incremental advance in a largely unexplored area.
The paper tackles the problem of proving program termination for large systems by developing an interprocedural termination analysis for C programs, showing that their tool 2LS outperforms state-of-the-art alternatives in efficiency while maintaining comparable precision.
Proving program termination is key to guaranteeing absence of undesirable behaviour, such as hanging programs and even security vulnerabilities such as denial-of-service attacks. To make termination checks scale to large systems, interprocedural termination analysis seems essential, which is a largely unexplored area of research in termination analysis, where most effort has focussed on difficult single-procedure problems. We present a modular termination analysis for C programs using template-based interprocedural summarisation. Our analysis combines a context-sensitive, over-approximating forward analysis with the inference of under-approximating preconditions for termination. Bit-precise termination arguments are synthesised over lexicographic linear ranking function templates. Our experimental results show that our tool 2LS outperforms state-of-the-art alternatives, and demonstrate the clear advantage of interprocedural reasoning over monolithic analysis in terms of efficiency, while retaining comparable precision.