[LLVMdev] advice on default options for building LLVM-GCC on Ubuntu Linux

Bill Wendling
Tue, 07 Apr 2009 18:17:20 -0000

On Tue, Apr 7, 2009 at 12:38 AM, Duncan Sands <baldrick at free.fr>
wrote:
> Hi Bill,
>
>> We use GNUmakefile to trigger using the build_gcc script.
>
> thanks for the explanation, but I still don't understand why
> it is done this way.  Why not just get Apple people to run some
> script, rather than trying to have "make" automagically do an
> Apple build?
>
It's more complicated than that. Suffice it to say that we wouldn't be
able to get the people who need to use GNUmakefile/build_gcc to change
just for our team (it's more than just our team that is required to do
this). In truth, they do have this. It's called "xcodebuild". But
llvm-gcc is very incompatible with this method of building.

>> It's not
>> ideal, but it's all we have at the moment. For LLVM, we placed
those
>> files in a subdirectory. This isn't ideal because of our build
>> processes, but was better than the alternative. We would *really*
>> prefer not doing the same thing to LLVM-GCC. Because we've been
>> building LLVM-GCC with srcdir != objdir for years now, it shouldn't
be
>> too much of a burden. . .
>>
>>  From what I understand, FSF GCC doesn't recommend building with
>> srcdir == objdir. Not that this necessarily means much to us, but
>> should indicate that it's not entirely out of the ordinary that we
>> require srcdir != objdir for LLVM-GCC. :-)
>
> Newcomers to llvm-gcc regularly try to build with srcdir == objdir.
> Some of them come on irc and ask about why it fails, but probably
> most of them just give up on llvm-gcc.
>
I understand. Believe me, I'm not a big fan of this method of building
llvm-gcc either. But I'm not a Makefile guru, so I don't know how to
make the two systems of building llvm-gcc compatible. Is there a FAQ
entry on this? If not, I'll add one.

-bw