Teresa Johnson
Software Engineer at Google
Los Gatos, California, United States
Summary
🤩
Rockstar🎓
Top SchoolTeresa Johnson is a seasoned software engineer with 14+ years of professional experience and a deep academic grounding in electrical and computer engineering from UIUC. Based in Los Gatos, she has spent over a decade at Google after a long tenure leading compiler development and research at Hewlett-Packard. Her expertise centers on compiler and toolchain back-end work—ThinLTO, LTO, LLVM/Clang, and LLVM-based optimizations—where she has improved debug info handling, hot-cold splitting, and MemProf context disambiguation. Teresa’s open-source contributions to high-profile projects like the LLVM monorepo and Apple’s Swift toolchain demonstrate a rare blend of careful refactoring, performance-minded data-structure work, and production-focused feature integration. Colleagues rely on her for pragmatic, low-level problem solving that bridges research-quality rigor with shipping robust compiler features. An understated detail: she regularly surfaces subtle correctness fixes (e.g., loop metadata handling and profile-aware naming) that prevent elusive runtime and profiling bugs.
14 years of coding experience
14 years of employment as a software developer
University of Illinois Urbana-Champaign
Github Skills (30)
c-language10
back-end-development10
llvm10
compiler-development10
data-structure10
code-generation10
compiler-construction10
compiler-optimization10
data-structures10
memory-profiling10
backend10
cprogramming-language10
optimization10
linker9
meta9
Programming languages (5)
Github contributions (5)
apple/swift-llvm
Jan 2016 - Feb 2019
Role in this project:
Backend Developer
Backend DeveloperContributions:113 commits in 3 years 1 month
Contributions summary:Teresa primarily contributed to the LLVM project by addressing issues related to debug information and the hot-cold splitting optimization pass. Their work involved modifying the debug information processing to correctly handle loop metadata during the stripping process. They also implemented improvements to the hot-cold split pass, adding functionality to correctly name extracted functions and include profile entry metadata when PGO is enabled.
llvm/llvm-project
Aug 2021 - Aug 2021
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:Back-end Developer
Back-end DeveloperContributions:880 reviews, 1 commit, 265 PRs in 1 day
Contributions summary:Teresa primarily worked on compiler and toolchain technologies, specifically focusing on optimizing and refactoring the MemProf context disambiguation process within the LLVM project. Their contributions included refactoring code for improved efficiency, such as switching to DenseMaps, leveraging remove_if, and optimizing data structure usage. They also added support for reporting hinted allocation sizes and improved the reliability and performance of context graph processing, including better handling of edge iterations.
compilerllvmtoolchain
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