Modular Termination Analysis
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.
Synthesising Interprocedural Bit-Precise Termination Proofs
H. Chen, C. David, D. Kroening, P. Schrammel, and B. Wachter
Extended version on arXiv
Our tool is maintained in a git repository. To get the tool, follow these instructions:
git clone https://github.com/diffblue/2ls
./2ls file.c --termination
See the 2LS website for further information.
There is a package for reproducing the experiments reported in the paper.