Generating compilation databases

You can generate compilation databases for consumption by tools such as clangd and clang-tidy by running the following BXL script:

buck2 bxl prelude//cxx/tools/compilation_database.bxl:generate -- --targets ...

The script will generate a compilation database for all source and header inputs to the targets listed on the command line. The path to the database is printed to stdout. Note that files that are referenced by multiple targets will have multiple associated entries in the database, which may not be desirable in all circumstances. For example, clang-tidy runs analysis for each entry sequentially when the file being linted has several entries.

It is common to symlink the resulting data at the root of the repository:

ln -sf $(buck2 bxl prelude//cxx/tools/compilation_database.bxl:generate -- --targets ...) $(git rev-parse --show-toplevel)

Since the path to the script is rather long, consider setting up an alias in your repository:

# `comp_db.bxl`

load("@prelude//cxx/tools/compilation_database.bxl:generate", "generate")

gen = generate

ln -sf $(buck2 bxl comp_db.bxl:gen -- --targets ...) $(git rev-parse --show-toplevel)

Providing better ergonomics for BXL scripts (such as enabling something like buck2 comp_db) is being discussed here.