Placing llvm-tools installed via rustup onto the PATH

Problem you are trying to solve

I have been working with the llvm-tools-preview component (in this case llvm-profdata).

These executables seem to be installed into an atypical bin directory inside the toolchain directory:

# location of llvm-profdata
~/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/bin/llvm-profdata

# location of rustc
~/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc

This means that for whatever combination of OS / target / toolchain I am running, I need to deduce the correct path to llvm-profdata myself. See for example https://github.com/pydantic/pydantic-core/blob/5c696e5ab32f323753f6c4da0000f4475225673c/.github/workflows/ci.yml#L471

Solution you'd like

It would be nice to have a supported way in rustup to run llvm-profdata for the target toolchain. Maybe rustup run could add this bin directory onto the PATH, so that e.g. rustup run stable llvm-profdata just works.

Notes

No response

Start with the rustup run command and how it selects a target toolchain, then inspect how the toolchain's bin directories are exposed. Check the llvm-tools-preview layout described in the issue and add coverage for invoking llvm-profdata through rustup run; done means the command works without manually constructing a target-specific path.