Nicolas Pierron
Compiler Engineer at Mozilla Corporation
Greater Paris Metropolitan Region France
Summary
🤩
Rockstar🎓
Top SchoolNicolas Pierron is a seasoned compiler engineer with 18 years of experience building and optimizing low-level systems, currently contributing to Mozilla's IonMonkey JIT and the Cranelift code generator in the Bytecode Alliance ecosystem. His work spans x86/ARM code generation, legalization passes, and JIT optimizations for high-performance JavaScript and WebAssembly runtimes, with notable contributions to wasmtime and Firefox internals. Deeply rooted in functional and language-oriented design, he helped introduce modularity to NixOS and authored papers on distribution design and semantics-driven disambiguation. Nicolas combines systems-level pragmatism (self-taught IA-32 reverse engineering and binary patching) with academic rigor from EPITA and studies in fundamental physics, favoring core-system challenges over UI polish. He’s equally comfortable improving build automation and developer workflows—having modernized Nix-based Firefox builds—and enjoys generalizing complex codebases into elegant, reusable abstractions. Fluent in French and English, he thrives on technically demanding problems and a methodical, end-to-end approach to solution design.
18 years of coding experience
4 years of employment as a software developer
Engineer, Computer Science, Engineer, Computer Science at EPITA: Ecole d'Ingénieurs en InformatiqueEnglish, English at Shafston UniversityFun, Fundamental Physics, Fun, Fundamental Physics at Pierre and Marie Curie University
French, English
Github Skills (28)
javascript10
c-language10
nix10
rust-wasm10
x8610
code-generation10
wasmer10
x86-6410
build-automation10
compile10
compiler-optimization10
arm10
wasmtime10
webassembly10
rust10
Programming languages (17)
Github contributions (5)
mozilla/nixpkgs-mozilla
Jul 2016 - Nov 2021
Mozilla overlay for Nixpkgs.
Role in this project:
DevOps Engineer & Build Automation Engineer
DevOps Engineer & Build Automation EngineerContributions:49 reviews, 79 commits, 132 PRs in 5 years 5 months
Contributions summary:Nicolas primarily focused on improving the build environment and automating the build process for the Firefox project. Their contributions include fixing compiler issues related to clang versions, adding dependencies for building Gecko within a Nix environment, and streamlining the integration of Rust and Cargo. They implemented enhancements to the Nix build system, including creating a FHS environment and adding debugging tools, and also integrated auto-updating of Firefox binaries. These modifications directly impacted the build process and developer experience.
nix-overlaynixosrustlangoverlaymozilla
mozilla/gecko-dev
Nov 2012 - Dec 2022
Read-only Git mirror of the Mercurial gecko repositories at https://hg.mozilla.org. How to contribute: https://firefox-source-docs.mozilla.org/contributing/contribution_quickref.html
Role in this project:Backend Developer
Backend DeveloperContributions:690 commits in 10 years 2 months
Contributions summary:Nicolas primarily focused on improving the JavaScript engine's JIT compiler within the Gecko rendering engine. Their work involved optimizing memory management related to JIT code, specifically making code writable and pre-allocating indices for safepoints and OSI points. The contributions also included enhancements to the code generator, such as refactoring the out-of-line code management and fixing aliasing issues in the MIR. Furthermore, the user added a shell option to emulate WebAudio worklets and fixed an ARM64 related bug.
repositoriesfirefoxmercurialgit-mirrormozilla
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