Vladimír Štill

Petr Ročkai, Vladimír Štill, Ivana černá et al.

In this paper, we introduce the concept of a virtual machine with graph-organised memory as a versatile backend for both explicit-state and abstraction-driven verification of software. Our virtual machine uses the LLVM IR as its instruction set, enriched with a small set of hypercalls. We show that the provided hypercalls are sufficient to implement a small operating system, which can then be linked with applications to provide a POSIX-compatible verification environment. Finally, we demonstrate the viability of the approach through a comparison with a more traditionally-designed LLVM model checker.

Vladimír Štill, Petr Ročkai, Jiří Barnat

An important step toward adoption of formal methods in software development is support for mainstream programming languages. Unfortunately, these languages are often rather complex and come with substantial standard libraries. However, by choosing a suitable intermediate language, most of the complexity can be delegated to existing execution-oriented (as opposed to verification-oriented) compiler frontends and standard library implementations. In this paper, we describe how support for C++ exceptions can take advantage of the same principle. Our work is based on DiVM, an LLVM-derived, verification-friendly intermediate language. Our implementation consists of 2 parts: an implementation of the `libunwind` platform API which is linked to the program under test and consists of 9 C functions. The other part is a preprocessor for LLVM bitcode which prepares exception-related metadata and replaces associated special-purpose LLVM instructions.