New ot-tidy.py script for development and CI

[ziuziakowska]

This replaces the existing ot-tidy.sh script with a new Python script.

This new script should make it easier to run the linter locally in the same way as CI, as the older wrapper script did not have any usage information.

The script also checks for some misconfigurations and reports those - such as QEMU not being configured to use Clang which results in a different incompatible set of warning flags to be used with GCC to be used for clang-tidy.

In addition, this script adds a -j flag to run linting in parallel, using the run-clang-tidy wrapper that comes with clang-tidy. On my machine, this reduced linting time on the same set of files as CI from ~3 minutes to 30 seconds.

[jwnrt]

I get this error from the script:

$ scripts/opentitan/ot_tidy.py --ci-files
Could not parse 'clang-tidy' version string.

Here's my output of clang-tidy --version:

$ clang-tidy --version
LLVM (http://llvm.org/):
  LLVM version 16.0.2
  Optimized build.

I think it's because my version_line is the second line, not the first

[ziuziakowska]

I think it's because my version_line is the second line, not the first

Fixed it to look for that on any line.
Mine appeared like this:

$ clang-tidy-20 --version
Ubuntu LLVM version 20.1.2
  Optimized build.

[jwnrt]

Yep, that works now, thanks

[rivos-eblot]

I think several features are broken, and some are a bit fragile (parsing, ANSI management, ...).

Can you run flake8, as there are many outsized lines and argument aligment warning messages. Thanks.

[AlexJones0]

Thanks, I've left a couple of additional comments. This LGTM though and definitely makes local clang-tidy runs faster.

[jwnrt]

Regression failure is known and unrelated