Heejin Ahn
Software Engineer at Google
Mountain View, California, United States
Summary
🤩
Rockstar🎓
Top SchoolHeejin Ahn is a software engineer with nine years of experience specializing in compiler backends and WebAssembly toolchains, currently developing Wasm infrastructure at Google in Mountain View. Her open-source contributions to LLVM/Clang, Binaryen, Emscripten, and wabt show deep expertise in exception handling, setjmp/longjmp support, and low-level codegen optimizations that improved Wasm compatibility and tooling. She combines academic grounding from KAIST and Princeton with practical industry experience dating back to compiler work for a clustered VLIW at Samsung. Notably, her patches added new Wasm EH instructions and bridged platform-specific exception mechanisms, reflecting both protocol-level skill and attention to cross-platform interoperability. She’s as comfortable writing rigorous tests and refactors in major projects as she is diagnosing subtle parsing and alignment bugs in toolchains.
9 years of coding experience
8 years of employment as a software developer
Master of Arts (M.A.), Computer Science, Master of Arts (M.A.), Computer Science at Princeton UniversityThe University of MelbourneBachelor of Science (B.S.), Computer science, Bachelor of Science (B.S.), Computer science at Korea Advanced Institute of Science and Technology
English, Korean, Japanese
Github Skills (18)
c-language10
llvm10
low-level-programming10
compiler-design10
exception-handling10
compiler10
emscripten10
webassembly10
clangd10
cprogramming-language10
clang10
compiler-development9
type-check9
javascript9
thread9
Programming languages (10)
Github contributions (5)
WebAssembly/binaryen
Aug 2016 - Aug 2022
Optimizer and compiler/toolchain library for WebAssembly
Role in this project:
Backend Developer
Backend DeveloperContributions:1493 reviews, 239 commits, 531 PRs in 6 years 1 month
Contributions summary:Heejin appears to have focused on improving the Binaryen optimizer and compiler/toolchain library for WebAssembly. Their contributions included fixing parsing bugs, implementing asm.js style exception handling for WebAssembly, and supporting setjmp/longjmp functionality. The user also addressed alignment issues, and added support for tag-related elements in the code, suggesting a focus on core compiler infrastructure and low-level code optimization for WebAssembly.
compilersemscriptenc-plus-pluswebassemblytoolchain
llvm/llvm-project
Jan 2019 - Apr 2025
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:Back-end Developer
Back-end DeveloperContributions:177 reviews, 199 PRs, 275 pushes in 6 years 3 months
Contributions summary:Heejin primarily contributed to the WebAssembly (Wasm) backend of the LLVM project, with a focus on exception handling and associated compiler features. Their work involved implementing support for new Wasm EH instructions, including `try_table` and `throw_ref`, and integrating them with existing EH mechanisms like the legacy Itanium ABI. The user also worked on correcting rethrow index calculation and adding test cases for various exception handling scenarios. Their contributions improved the LLVM's compilation capabilities for Wasm's exception handling features.
compilerstechnologiesclangsubmittoolchain
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