[PLUG] How something compiles...

[robinsoq]

---------- Original Message ----------------------------------
From: Jeme A Brelin <jeme at brelin.net>
Reply-To: plug at lists.pdxlinux.org
Date:  Wed, 9 Jul 2003 23:38:15 -0700 (PDT)

>
>On Wed, 9 Jul 2003, robinsoq  wrote:
>> If you don't put optimizations into the spec file for gcc will configure
>> in general detect what your compiling on and optimize for that?
>
>What spec file?
>
Do an rpm -ql gcc on a Redhat 7.x or newer system and the spec file under
/usr/lib/gcc... something is where you can optimize your compiler
flags.  Strangely though, having done nothing to the global compiler flags
I don't get it why with my Linux From Scratch system that it would by 
default be compiling to the architecture of the host system.  Morover, I'm 
curious what is involved in compiling Linux's libraries for multiple 
architectures: K6, PIII, PII, PI, Duron, Athlon, and 386.  Theoretically, 
I would think through cross compilation that I could have all the 
possibilities.  Then again, compiling for 386 should work everywhere 
where I probably don't need the optimization.  Are all architecture
optimizations contained in Linux's libraries or would having multiple
architecture compatibility ( within the same architecture family ) mean
that you have to have executables compiled in multiple ways?  This would
probably mean a slightly different filesystem structure with a full Linux 
Filesystem Standard tree for each architecture choice.  Setting this up
generically would probably be done most easily by doing multiple LFS 
systems in seperate partitions, one for each architecture.  Talk about 
massive waste :-(  I think autoconfigure is causing optimization to
the host system's architecture.

     --  Michael