Compilation as Multi-Language Semantics
Abstract
Modeling interoperability between programs in different languages is a key problem when modeling verified and secure compilation, which has been successfully addressed using multi-language semantics. Unfortunately, existing models of compilation using multi-language semantics define two variants of each compiler pass: a syntactic translation on open terms to model compilation, and a run-time translation of closed terms at multi-language boundaries to model interoperability. In this talk, I discuss work-in-progress approach to uniformly model a compiler entirely as a reduction system on open term in a multi-language semantics, rather than as a syntactic translation. This simultaneously defines the compiler and the interoperability semantics, reducing duplication. It also provides interesting semantic insights. Normalization of the cross-language redexes performs ahead-of-time (AOT) compilation. Evaluation in the multi-language models just-in-time (JIT) compilation. Confluence of multi-language reduction implies compiler correctness, and part of the secure compilation proof (full abstraction), enabling focus on the difficult part of the proof. Subject reduction of the multi-language reduction implies type-preservation of the compiler.
Cite
@article{arxiv.2509.19613,
title = {Compilation as Multi-Language Semantics},
author = {William J. Bowman},
journal= {arXiv preprint arXiv:2509.19613},
year = {2025}
}