[build2] Using build2 with clang 6 (trunk) on windows

[Boris Kolpackov]

Username I Wanted Was Already Taken <usernameiwantedwasalreadytaken at gmail.com> writes:

> First of all thanks for the great work with Build2. I'm starting using it,
> but it seems a great tool.

Thanks, I am glad you like it so far!


> I am trying to compile a simple hello sample on windows. I have MSVC
> Community 2017 and Clang 6 (built from source) installed.

We haven't really tested this combination, but if you are willing to
provide some feedback (see below), I am sure we can make it work.


> C:\Tests\Build2\hello\clang-6>b
> ../hello/build\root.build:3:7: error: cc and bin module target mismatch
>   info: cc.target is x86_64-windows-msvc
>   info: bin.target is x86_64-windows-msvc

Hm, this definitely doesn't look right. Can you re-run it with --verbose 6
and send the output?


>   target     x86_64-windows-msvc (x86_64-pc-windows-msvc)
>   inc dirs
>     C:\LLVM\build\lib\clang\6.0.0\include\
>     C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.11.25503\include\
>     C:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\ucrt\
>     C:\Program Files (x86)\Windows Kits\10\include\10.0.16299.0\shared\
>     C:\Program Files (x86)\Windows Kits\10\include\10.0.16299.0\um\
>     C:\Program Files (x86)\Windows Kits\10\include\10.0.16299.0\winrt\

This is interesting, thanks for sending it. To support Clang with the
MSVC target I can see two immediate things that we will need to do:

1. We will need to remap Clang's 'x86_64-pc-windows-msvc' to build2's
   more precise 'x86_64-microsoft-win32-msvcNN.N' where NN.N is the
   MSVC runtime version.

   In this light, do you know if there is a way to query Clang for
   the MSVC runtime it is using? I guess we could get it from the
   '...\MSVC\14.11.25503\include' bit of the include path but that
   feels rather hackish.

2. We will need to find the rest of the toolchain (link.exe, rc.exe,
   mt.exe, etc).

   When you use Clang, are you expected to run it from the corresponding
   MSVC development command prompt (where the PATH is already set to
   include the correct variants of these tools)?

   Also, can you show the output of this command:

   clang -print-search-dirs

Thanks,
Boris