Updating LLVM/Clang support for VS for VS2017

CCing Zach, who did a lot of the VS 2017 support work (AFAIK), and Reid, who’s the general Microsoft support overlord.

By full support for VS 2017, do you mean within the IDE itself? I haven’t ever used clang from within the VS IDE, so I can’t speak to that. All non-IDE stuff should work though, as far as I know.

Which compiler options/switches specifically are missing? Filing bugs for those at https://bugs.llvm.org/ is probably the way to go. clang-cl does support the /std switch, at least. 5.0 supports /std:c++14 and /std:c++latest, and trunk adds support for /std:c++17.

I’m curious to know what’s missing as well. The only thing I can think of off the top of my head is that we haven’t updated the VS integration to add clang-cl as a toolchain to the IDE. But, I don’t know that we even did that for 2015 either, that has been stale for quite a while.

As far as C++ language and ABI compatibility, I’m not aware of anything that’s missing.

I also imagine Osman refers to the Visual Studio IDE integration, not
so much the compiler itself.

The last time we updated that was for the VS "14" CTP.

This stuff lives in LLVM's tools/msbuild/ directory, and contributions
would be very welcome.