Fails to build sys/i386/boot2 with gcc 4.9

[Warner Losh]

> On Mar 29, 2015, at 2:29 PM, Craig Rodrigues <rodrigc at FreeBSD.org> wrote:
> 
> On Sun, Mar 29, 2015 at 11:04 AM, Warner Losh <imp at bsdimp.com> wrote:
> 
> If we built a UFS1-only boot2, that would fit in the 7.5k we have left
> to play with. We could then build a UFS2-only boot2 that would easily
> fit in the like 32k limit that UFS2 has.
> 
> The only reason we went to supporting both was to have something
> universal. Since it requires a reformat to go from UFS1 -> UFS2 we
> wanted the transition to be as smooth as possible so you didn’t have
> to add boot blocks into the mix.
> 
> Now the only people that use UFS1 are people with really old systems
> that are never going to upgrade, or people building new systems with
> UFS1 because they are space constrained (for whatever reasons that
> we’re not going to debate here: they are still real).
> 
> In the past 5 years, I have worked on some embedded systems where UFS1 was chosen because of very low memory and disk space requirements.
> So those systems are real and out there.
> 
> Just out of curiousity, what is it about newer compilers that cause
> the size of boot2 to increase so much?
> 
> Could we do some silly things like removing/reducing the use of printf()
> to save some more bytes, in order to buy us more time, before having
> to rewrite everything? :)

Removing printf isn’t going to save us. It usually compiles to 80-120 bytes.

I think the only sane way forward is boot2.ufs1 an boot2.ufs2 plus maybe
some safety belts in the boot block splatter programs to prevent
brickification.

Warner

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