POLYVER: A compositional approach for polyglot system modeling and verification

Many software systems are polyglot; that is, they comprise programs implemented in a combination of programming languages. Program verifiers, however, tend to be customized for individual languages. Verification by compiling to a
common encoding requires supporting full language syntax and semantics which is prohibitive for modern languages. We present POLYVER, an alternative compositional approach to polyglot verification that bootstraps off-the-shelf language-specific verifiers with abstraction and synthesis. POLYVER uses contracts written in an intermediate language to abstract individual procedures in the system. Our verification approach uses language-specific verifiers (e.g., for C or Rust) to validate these contracts and the UCLID5 model checker for com- positionally verifying a temporal property on the overall system using the contracts. The intermediate language sidesteps the need for compiling implementation languages to a common encoding, a key obstacle with polyglot verification. Finally, POLYVER automates the generation of contracts using synthesis oracles such as large-language-models (LLMs). Overall POLYVER performs contract synthesis and verification in a counterexample-guided abstraction refinement and inductive synthesis (CEGIS-CEGAR) loop to verify the system-level property. We use POLYVER to verify programs in the Lingua Franca polyglot language. We are able to verify systems with C and Rust procedures, as well as C language fragments that were unsupported in previous work.