Clang-Scan-Deps Lands In Clang 9.0 For Much Faster Dependency Scanning

Landing this week in the LLVM Clang 9.0 development code-base is the new clang-scan-deps tool for much faster scanning of files for dependencies compared to the traditional pre-processor based approach.

Development of clang-scan-deps was led by Apple's compiler team and delivers up to around ten (10) times faster performance for scanning of dependencies/modules before compiling compared to the pre-processor-based scanning.

Clang-scan-deps is designed to scale out nicely for code-bases with many C++ files and is working on proper C++20 modules support. Ultimately they plan to provide integration of clang-scan-deps with the Clangd service and more for IDE integration and other use-cases.

The initial clang-scan-deps code merged this week into Clang SVN/Git. LLVM/Clang 9.0 is expected for release around September given their usual release cadence.