CppCon 2017: Teresa Johnson “ThinLTO: Scalable and Incremental Link-Time Optimization”

Teresa Johnson explains ThinLTO, a scalable compilation model in LLVM that enables whole-program optimization and fast incremental builds.

CppCon.org — Presentation Slides, PDFs, Source Code and other presenter materials are available at: github.com/CppCon/CppCon2017 — Whole program optimization enables higher performance in C++ applications, because of the expanded scope for analysis and optimization. However, the memory and time required to optimize the entire program together as a single unit traditionally has made whole program optimization infeasible for complex and large C++ applications, such as those being built at Google. Additionally, traditional whole program optimization frameworks have not supported fast incremental builds. ThinLTO (Thin Link Time Optimization) is a new compilation model that was recently deployed in the LLVM compiler toolchain to enable scalable whole program optimization for these huge C++ applications, and additionally enables the fast incremental builds required for use in day-to-day development. In this talk we’ll describe why whole program optimization is beneficial for C++ applications, how the ThinLTO compilation model enables scalable and incremental builds, and how ThinLTO can be integrated with distributed build systems for even faster whole program builds. Additionally, we’ll describe implications for C++ developers. — Teresa Johnson: Software Engineer, Google Teresa Johnson works on compiler optimization at Google. Prior to joining Google in 2011, she developed compiler optimizations for the Itanium compiler at HP, and received a PhD from the University of Illinois at Urbana-Champaign. — Videos Filmed & Edited by Bash Films: BashFilms.com Work at Hudson River Trading (HRT): tinyurl.com/safxfctf --- Videos Filmed & Edited by Bash Films: BashFilms.com