DeepSpec Summer School, July 13-28, 2017
The formal verification of compilers Xavier Leroy
Formal semantics of programming languages supports not only reasoning over individual programs (program correctness), but also reasoning over program transformations and static analyses, as typically found in compilers (tool correctness). With the help of a proof assistant, we can prove semantic preservation properties of program transformations and semantic soundness properties of static analyses that greatly increase the confidence we can have in compilers and program verification tools.
The topics covered in this lecture include:
- Non-optimizing compilation of a structured imperative language to a virtual machine, and its correctness proof.
- Notions of semantic preservation during compilation.
- Various forms of operational semantics and their mechanization in Coq: big-step, small-step, small-step with continuations.
- Examples of program optimizations: dead code elimination, register allocation.
- Compiler verification "in the large" : an overview of the CompCert verified C compiler.
We use the Coq proof assistant and build on the formalization of the IMP language from Logical Foundations by Pierce et al.
Lecture material
The dsss17 repository contains lecture notes and homework for this lecture in the compiler/ directory.
The slides for the lecture.