[llvm-commits] [PATCH] Add MSVC multi processor compilation to build system

[Erik Olofsson]

> -----Original Message-----
> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> bounces at cs.uiuc.edu] On Behalf Of Óscar Fuentes

> IMHO, we must have a very good reason for enabling by default a feature
> that it is disabled by default on the build tool. If the user is expected to add
> /MP to his project setting in case he wants multiprocessor builds, we
> shouldn't do more.

I think Microsoft leaves this off by default because it's incompatible with some other options. Those options are not used by llvm however. I think it would be useful when a developer compiles llvm on Microsoft compilers the compilation should be as fast as possible out of the box. If we leave this off by default most developers will not know about the option and will not benefit from the feature.

> MSVC is true for all build tools that work with the MSVC compiler. AFAIK
> /MP only works with MSBuild or whatever is used nowadays by the IDE.
> Please use MSVC_IDE instead of MSVC.

Ok will do. It won't break the build though as it's a compiler option. If the build tool doesn't provide several translation units in one invocation it will simply ignore the parameter.

Regards,
Erik