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

Dale Johannesen
Tue, 07 Apr 2009 19:07:19 -0000

On Apr 7, 2009, at 11:47 AMPDT, Tanya M. Lattner wrote:

>
>>>>  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.

If they can't figure out how to find and read a README file, do we
really want them?

>> 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.
>
> This is stated in the README.LLVM and people rarely follow the
> directions in there too. You can't force people to read documentation.

No you can't, but you need not be sympathetic when they don't.

You can't really build gcc without reading at least some of the
documentation either.  The problem we have is that some people come in
expecting the build procedure to be identical to that of gcc, and it
isn't.   (Calling it llvm-gcc doesn't help, but it's too late now.)

Perhaps:

% make
A make target is required.  If you think you know how to build llvm-
gcc just because you know how to build gcc, you're wrong.  Please read
README.LLVM.

Did I mention there's a reason I don't do user interfaces? :)