Fails to build sys/i386/boot2 with gcc 4.9

[Warner Losh]

> On Mar 29, 2015, at 6:37 PM, Garrett Cooper <yaneurabeya at gmail.com> wrote:
> 
>> 
>> On Mar 29, 2015, at 15:56, Warner Losh <imp at bsdimp.com> wrote:
>> 
>>> 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.
> 
> Since the proposal to split up the code by filesystems is on the table, would it make sense to do something similar for zfs?
> Thanks!

zfs isn’t in boot2 by default, just ufs1 and ufs2, so I on’t understand the question.

Warner

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