Compiling FreeBSD with GCC 4.3+

[David Naylor]

On Tuesday 21 April 2009 10:32:04 Mel Flynn wrote:
> Hi David,
>
> On Monday 20 April 2009 21:48:39 David Naylor wrote:
> > There has been an article recently published by phoronix
> > (http://www.phoronix.com/scan.php?page=article&item=pcbsd_vs_kubuntu&num=
> >1) that compares PC-BSD to Kubuntu.  Kubuntu uses GCC 4.3.3 compared to
> > FreeBSD's GCC 4.2.2.  There is a considerable performance difference
> > between the two OS's, the article contributes this difference to the
> > compiler.
>
> Nice shot in the dark, since except the calculations a lot of these are
> influenced by "journaled FS vs stock UFS".

I know, benchmarking anything but the simplest things are influenced by too 
many factors.  Pity it doesn't provide an unbiased comparison of FreeBSD and 
Linux.  

> > In order to check if this is so (and to get the speed improvements of GCC
> > 4.3+) one needs to compile the ports (and preferable world/kernel as
> > well) with GCC 4.3+.
>
> It's license is incompatible with world/kernel. 

What type of incompatibility.  I know FreeBSD has reservations about GPLv3 (I 
personally don't understand why everyone cannot be friends and use BSD 
Licenses).  So is this a policy incompatibility or a legal one (i.e. would it 
be 'illegal' for me to use GCC 4.3+ to compile world/kernel, as an 
end-user/consumer of FreeBSD).  I assume the same discussion applies to 
binutils.  

> That said, install 
> lang/gcc43 and set CC/CXX for ports. World/kernel would be a lot harder.
> Maybe setting WITHOUT_GCC in /etc/src.conf and setting CC/CXX would work,
> but there's quite a few modifications to gcc that aren't in ports lang/gcc,
> so I have my doubts.

I suppose it would be nice if there was an easy way to use an out-of-source 
compiler in FreeBSD.  Like set PORTS_COMPILER=gcc43 and the port will 
installed and used... One may have dreams.  

> > Is there an easy way to set this up and does anyone know the
> > compatibility of world/kernel/ports with GCC 4.3+?
> >
> > Also has anyone tried this and benchmarked the result?
>
> Not me, but be sure to stick around for the new non-gcc compiler coming to
> a FreeBSD near you. And with the work done by Marcel Molenaar on gpart,
> hopefully we can have ZFS and gjournal as choices in the installer.

You mean llvm, waiting patiently.  I suppose my suggestion above will become 
even more important (at least for compiling ports) since it will be a while 
till llvm has decent c++ support.  

Thanks for your reply
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 195 bytes
Desc: This is a digitally signed message part.
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20090421/a689b1c4/attachment.pgp