[PATCH] D26579: [cmake] Allow CMAKE_BUILD_TYPE=Gentoo

[Michał Górny via llvm-commits]

mgorny added a comment.

In https://reviews.llvm.org/D26579#593739, @mehdi_amini wrote:

> In https://reviews.llvm.org/D26579#593711, @mgorny wrote:
>
> > In https://reviews.llvm.org/D26579#593702, @mehdi_amini wrote:
> >
> > > There is a good reason Gento is doing it: to make sure they have full control over compiler flags in the Gentoo configuration.  See here: https://github.com/coreos/portage-stable/blob/master/eclass/cmake-utils.eclass#L43
> > >
> > > However accepting the value "Gentoo" here won't address the problem, it'll just mask it. We are expecting values from this list in multiple place.
> >
> >
> > Yes. I can volunteer to make sure that Gentoo appears there whenever desired, if that's what you need.
>
>
> That's not what *I* need, that's what *you* need.


I need things to work somehow. Now I'm looking for a solution that would satisfy the other LLVM developers while making them work for us.

>>> For example in llvm/cmake/modules/HandleLLVMOptions.cmake:
>>> 
>>>   # On non-Debug builds cmake automatically defines NDEBUG, so we
>>>   # explicitly undefine it:
>>>   if( NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" )
>>>    
>> 
>> Just to be clear, here 'Gentoo' is not expected since CMake doesn't control -DNDEBUG for this build type.
> 
> But here we're gonna add "-UNDEBUG" when the build type is Gentoo, is it OK?
> 
>> 
>> 
>>>   if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" AND
>>>       NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELWITHDEBINFO")
>>>     add_flag_if_supported("-gline-tables-only" GLINE_TABLES_ONLY)
>>>   endif()
>>>    
>> 
>> …and here it's not expected since appending -g flags implicitly is against a Gentoo policy.
> 
> Right, and with BUILD_TYPE=Gentoo this will add "-gline-tables-only".
> 
> I don't know what is the right thing for each of these cases, and this alone shows that you'll need to have a clear description and requirement for this "special" build type if you expect to have it supported upstream.

You are right, this is quite confusing.


https://reviews.llvm.org/D26579