Not exactly sure how to title this nicely.
I've got a large CMake project that is targeting the MSVC compiler with Ninja build files. I'd like to integrate Clang-Tidy to analyze our code but am hitting a few roadblocks.
Differing Flags between Clang-tidy and MSVC
Our project uses certain MSVC options like /FI to include certain files. These are not recognized when clang-tidy. This represents a barrier for using the CMAKE_<LANG>_CLANG_TIDY as I would essentially have to do a different configuration for actually compiling the files and another for just doing tidy.
How do I remedy an issue like this beyond just find and replace the flags from the variables used by each source file (ie, string(REPLACE "/FI" "-include" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})). Doing this is likely to break whenever a new option is added. I believe that this directly relates to my next part of the question.
Clang Tidy Integration per-Target
When you set CMAKE_<LANG>_CLANG_TIDY, you get tidy run on the build command of every source file rather than a seperate "tidy" target. This is generally fine for a debug build or a single target.
I'd be interested to have tidy run as a separate target (--target tidy) that just reports the warnings / fixes from clang-tidy. I would imagine doing this something like (pseudo code):
function(tidy-target tgt)
add_custom_target(${tgt}_tidy)
for source in tgt:
add_custom_target(${source}_tidy "${CLANG_TIDY} source")
# Copy all flags, includes, options, defines and pass to clang tidy, how?
add_dependency(${tgt}_tidy ${source}_tidy)
endfunction()
This would give me the benefit of integrating this check slowly onto the larger project (as there will be a lot of issues to move through). As well, it gives the ability to easily separate a dry-run from a fix invocation of tidy. Just wanted thoughts on this process.
I think the most finicky part will be setting up the custom targets to ensure they have all of the correct options as the real build. I wonder if there is a built-in way around something like this. Perhaps, how does CMake do this when using the traditional CMAKE_<LANG>_CLANG_TIDY variable? Or am I stuck just copying each _FLAGS variable into the custom target?
EDIT:
Seems like maybe some of the options such as /FI are properly respected by clang-tidy, but not all the time. Some of my files might be generating with poorly formed commands...
