Fangrui Song
Staff Software Engineer at Tesla
Earth, Texas, United States
Summary
🤩
Rockstar🎓
Top SchoolFangrui Song is a systems-focused software engineer and longtime open-source contributor with 15 years of experience working deep in compiler, runtime, and tooling ecosystems. Based in Texas, they’ve made substantive contributions to high-profile projects such as LLVM/Clang, glibc, libc++, TensorFlow, and Emacs LSP, often touching low-level build systems, code generation, and platform compatibility. Their work ranges from fixing static analyzer issues and thread-local storage mechanics to improving LLVM instruction selection and integrating LLVM updates into TensorFlow, demonstrating fluency in C, C++, and build automation. Fangrui also brings QA and tooling strengths—modernizing tests for Python 3, refining language-server integrations, and enhancing debugging pretty-printers—so their impact reliably improves developer experience as well as runtime correctness. A retired competitive algo/CTF and student cluster competitor, they combine performance-minded engineering with a taste for hard technical puzzles. Colleagues rely on them for careful refactors and pragmatic fixes that keep complex toolchains maintainable and performant.
15 years of coding experience
8 years of employment as a software developer
No. 2 High School Attached to East China Normal UniversityComputer Science and Technology Computer Science and Technology, Computer Science and Technology Computer Science and Technology at Tsinghua University
Chinese, English
Stackoverflow
356reputation
3kreached
3answers
0questions
Github Skills (94)
python10
compiler-development10
testing10
language-server-protocol10
c1110
c1710
dt10
arm10
dynamic-linking10
clang10
optimization10
astm10
matcher10
relocate10
static-analysis10
Programming languages (37)
Github contributions (5)
MaskRay/ccls
Nov 2017 - Jan 2023
C/C++/ObjC language server supporting cross references, hierarchies, completion and semantic highlighting
Role in this project:
Back-end Developer
Back-end DeveloperContributions:25 releases, 18 reviews, 1400 commits in 5 years 2 months
Contributions summary:Fangrui contributed code to enhance the ccls codebase by adding `Generation gen` fields to the `QueryFunc`, `QueryType`, and `QueryVar` structures, along with corresponding functions to handle these fields. They also made changes to several files to incorporate the `Generation gen` fields and the new functions, updating the code to ensure the proper tracking and management of generated data. Further, they added support to the textDocument/references and ccls/memberHierarchy functionalities.
cpphierarchieslsp-serverobjcide
llvm/llvm-project
Oct 2021 - Jan 2023
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
Role in this project:Back-end Developer & Software Architect
Back-end Developer & Software ArchitectContributions:3265 reviews, 43 commits, 720 PRs in 1 year 3 months
Contributions summary:Fangrui's contributions primarily focused on low-level infrastructure and architecture modifications. They worked on adapting Bazel build configurations and test suite, indicating familiarity with build systems and software build processes. They also made adjustments to the code generation process, refactoring certain aspects of the system, and fixing bugs.
compilerstechnologiesclangsubmittoolchain
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