Cross platform building best practices (building 6 on 7)

Julian Elischer julian at
Fri Jun 20 21:58:57 UTC 2008

Alexander Sack wrote:
> On Fri, Jun 20, 2008 at 5:14 PM, Julian Elischer <julian at> wrote:
>> Alexander Sack wrote:
>>> On Thu, Jun 19, 2008 at 11:22 AM, Garrett Cooper <yanefbsd at>
>>> wrote:
>>>> On Thu, Jun 19, 2008 at 6:29 AM, Alexander Sack <pisymbol at>
>>>> wrote:
>>>>> Hello Folks:
>>>>> I've done a lot of Googling and scouring the lists about this
>>>>> particular subject so I apologize for rehashing it.  However, I'm
>>>>> still confused on what's the best way to perform BSD cross platform
>>>>> builds.  Ideally what I want to have is an environment whereby I can
>>>>> build a 6.1-RELEASE tree on a 7.0-RELEASE box.  I thought originally I
>>>>> could check out a 6.1 release version, perform make world, and then
>>>>> use the output of that build as either a basis for a jail or a
>>>>> toolchain.  However, as noted by previous threads, 6.x doesn't build
>>>>> on a 7.x due to gcc4/binutils compatibility issues (please correct me
>>>>> if I'm wrong).  I then thought I could potentially download a patched
>>>>> binutils, copy it into src/contrib/binutils and that would potentially
>>>>> fix it.  No dice (and I'm still debugging why since this binutils
>>>>> package DOES build outside of the make world infrastructure without
>>>>> issue, this very well could be pilot error on my part since I didn't
>>>>> update the VERSION string and didn't trim the source files as per the
>>>>> FreeBSD-deleteList etc.).
>>>>> I THEN thought if I build/install a gcc-3.x/bintuils toolchain I could
>>>>> complie a 6.x on a 7.x machine.  Well I haven't done that yet since at
>>>>> this point I believe I'm diverged from the path of FreeBSD build
>>>>> enlightenment!  Moreover, if would be NICE if I could bootstrap the
>>>>> normal dev tools from the exiting make world build tree.  I'm not yet
>>>>> ready for a lot of hackery on the build tree without asking around.
>>>>> :D!
>>>>> Does anyone due cross-platform builds (without host virtualization)?
>>>>> Thanks!
>>>>> -aps
>>>> (I'll stick to just hackers@ because I don't want to pollute
>>>> questions@ unnecessarily)
>>> Sorry I felt really bad actually cc'ing questions its just that my
>>> last groking produced many threads in freebsd-questions as opposed to
>>> hackers.  I'll try to be more attentive to my posts (I have a habit
>>> cc'ing multiple forums because sometimes they apply but questions is
>>> for normal troubleshooting, not cross-platform build issues!).
>>>> You touched on an important point. There were some code quality issues
>>>> (I think) with 6.x that were resolved moving to 7.x, which caused
>>>> gcc-4.2.x to barf.
>>> Probably but I'm not trying to point fingers!  :D!
>>>> gcc-4.2.x requires a newer version of binutils, just because (for API
>>>> / usage compatibility).
>>> Yea understood.  To be honest, this isn't documented very readily.  I
>>> first thought it was pilot error on me, then I decided to take a look
>>> at what failed to compile (I believe it was an innocent extern).  And
>>> then got lost in gcc/binutils hell.  Luckily I've smelled this problem
>>> before and after some research confirmed by suspicion.
>>>> What you should probably do is create a jail then do your development
>>>> for 6.x in a jail, 7.x in another, and (if you're bold enough ;)...)
>>>> do 8.x development in yet a third. Jail's are a much better way to
>>>> isolate things such that you don't have to worry about toolchain
>>>> issues like these and are able to setup a sourcebase as the devs
>>>> intended it (for the most part; you may run into issues with sysctls
>>>> and virtual kernel stuff like that, but cest la vie... there isn't a
>>>> better way I know of than that outside of running a VM).
>>> I figured you were going ot say that Garrett.  Well OK, but I still
>>> need to bootstrap my dev environment for 6.x development on 7.x.
>>> Since binutils compatibility makes my 6.x make world barf on 7.x,
>>> where should I go?  I HAVE not parsed through a lot of the build
>>> infrastructure yet but it would seem to be IF make world bootstraps
>>> the world including the development tools, why can't I update
>>> binutils/gcc inplace and then compile (or is this a regression issue
>>> which I failed to grasp).  Or do I need to update binutils on my
>>> *host* system itself?  i.e. what I'm really asking is does make world
>>> bootstrap the right bintuils/gcc etc. and then use THAT to compile the
>>> rest or does it just perform a host build of everything and plops it
>>> in DESTDIR?
>>> Hope I make some sense here (still a n00b)....
>> One thing we always strive for in FreeBSD is an upgrade path.
>> As a general rule, a newer system should be able to run a jail
>> populated with an earlier system. There are some small exceptions,
>> for example you may need a new version of netstat, ps and libkvm
>> in your jail. possibly grab them from the /rescue on the new system
>> so they are statically linked.
>> also 8.x systems will require that threaded programs from 6.x be dynamically
>> linked so that they can be remapped to use libthr instead of libkse as
>> libkse is not supported in 8.
> So you are talking about binary/ABI compatibility yes?  So I would
> assume what you are saying is I can take a 6.x system, create a
> filesystem tarball, drop it on a 7.x system and then create a jail out
> of it.


>> asside from those I think that just about every thing else should be fine..
>> I've run a FreeBSD 1.1 chroot on a freeBSD 7 system
>> (I had to make 1 very small fix).
>> At Ironport we build 4.x binaries on 6.x systems by spinning off
>> a 4.x chroot as prart of the build process. (they need to link with 4.x
>> third party binaries) so it's very esay to do.
> I believe this answers my question but I want to confirm.  I THOUGHT
> about this but I wanted a more *cleanroom* approach.  That's all.
> -aps

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