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arXiv · 1601.05520

COGENT: Certified Compilation for a Functional Systems Language

Liam O'Connor·Christine Rizkallah·Zilin Chen·Sidney Amani·Japheth Lim·Yutaka Nagashima·Thomas Sewell·Alex Hixon·Gabriele Keller·Toby Murray·Gerwin Klein
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Abstract

We present a self-certifying compiler for the COGENT systems language. COGENT is a restricted, polymorphic, higher-order, and purely functional language with linear types and without the need for a trusted runtime or garbage collector. It compiles to efficient C code that is designed to interoperate with existing C functions. The language is suited for layered systems code with minimal sharing such as file systems or network protocol control code. For a well-typed COGENT program, the compiler produces C code, a high-level shallow embedding of its semantics in Isabelle/HOL, and a proof that the C code correctly implements this embedding. The aim is for proof engineers to reason about the full semantics of real-world systems code productively and equationally, while retaining the interoperability and leanness of C. We describe the formal verification stages of the compiler, which include automated formal refinement calculi, a switch from imperative update semantics to functional value semantics formally justified by the linear type system, and a number of standard compiler phases such as type checking and monomorphisation. The compiler certificate is a series of language-level meta proofs and per-program translation validation phases, combined into one coherent top-level theorem in Isabelle/HOL.

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Liam O'Connor, Christine Rizkallah, Zilin Chen, Sidney Amani, Japheth Lim, Yutaka Nagashima, Thomas Sewell, Alex Hixon, Gabriele Keller, Toby Murray, Gerwin Klein. 2016-01-21. COGENT: Certified Compilation for a Functional Systems Language. https://arxiv.org/abs/1601.05520

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