Enabling level 4 warnings by default for MSVC builds

Following my recent round of changes to disable selected MSVC builds both the core llvm project and clang are building cleanly with MSVC 2013 Update 4 with the LLVM_ENABLE_WARNINGS option set to ‘true’ (enabling MSVC’s level 4 warnings). I have not built any other projects with MSVC, but I would expect at most a manageable, and possibly even useful, set of warnings to be produced.

The LLVM_ENABLE_WARNINGS option currently defaults to ‘false’ for MSVC builds due to the previously extremely high number of warnings produced. Now that the warnings that were judged to fall below the line of significance of have been disabled, I’d like to reverse the default to match builds with other compilers.

Does anyone object to doing so?



Hi Andy,

I think it is good idea. It would help projects that depends on LLVM as there is a lots of inline code in LLVM headers.

Do you need any help with that? I use VS quite often.

  • Paweł

Please do! I didn't realize the default value was based on usage of MSVC.
I've been enabling it manually for so long I'd forgotten I had to.