[LLVMdev] [cfe-dev] [RFC] Raising LLVM minimum required MSVC version to 2013 for trunk

[Kristof Beyls]

> >
> > This is a considerably more interesting case (at least to me) than
> > hypothetical benefits -- if we retain MSVC 2012 support, we will also
> > require /bigobj support, have slower compile times for ASTMatcher
> > projects, and slower benchmarks for clang-tidy. This points to
> > concrete benefits to expediting switching away from MSVC 2012, which
> > is why I am pinging this thread again.
> 
> I guess I'm a little surprised that /bigobj is such a compile-time hit,
> but haven't tried any benchmarking. Anyway, whatever works best for you.
> --paulr

I'm not 100% sure, but my understanding is that the huge number of template
instantiations is the root cause of the compile-time hit. It's the same root
cause that requires /bigobj to be needed, as each template instantiation
seems to need its own section? Therefore, /bigobj in itself probably doesn't
incur a compile-time hit, but rather the huge number of template instantiations
produced.
Aaron, did I understand correctly that moving to MSVC2013 would allow to
adapt the code so that no longer a huge number of templates need to be instantiated?

Thanks,

Kristof