Add "checkout_clang_tidy": True to .gclient file in the custom_vars (or use standalone-maximal.gclient which includes this).
"custom_vars": { "checkout_clang_tidy": True, }
gclient sync
Set up a build directory for the configuration you want to run. It doesn't need to be built yet. This can be a native build or a cross-compiled build.
Run tools/run-tricium-clang-tidy.py --help for instructions. Running the tool with --default takes about 12 minutes on a 10-core M1 Pro laptop and under 2.5 minutes on a 64-core (128-thread) cloud VM.
This will output a json file with the full findings, and a summary file with a nicely-formatted list of results.
Tips:
It's recommended to set up clangd and open a file in your IDE to see the errors in context (and to get an autofix button). In VSCode you can less the summary file to your terminal and then cmd-click/ctrl-click the lines to take you to the exact source line.
You can use clang-tidy to process individual source files and their headers like so: third_party/llvm-build/Release+Asserts/bin/clang-tidy -p out/debug SOURCE_FILES...
These must be source files - it isn't capable of processing header files directly.
Fixes can be applied with --fix. To fix just specific checks, add --checks=-*,CHECKS,TO,FIX. This is much slower to run over many files, as it‘s not parallelized. *If any file fails to compile, it won’t apply any fixes to any file.*
TODO(crbug.com/501491694): Investigate applying replacements from the *-findings.json file, using clang-apply-replacements. This would be somewhat limited because tricium_clang_tidy_script.py drops replacements when they‘re in a different file from the warning. Alternatively, see if there’s a way to automate it via clangd.
For additional info on running Clang-Tidy locally, see these instructions.