Re: [gentoo-dev] Re: GLEP draf for cross-compile support in multilib profiles

[Zac Medico]

On 07/01/2012 02:34 PM, Thomas Sachau wrote:
> Zac Medico schrieb:
>> On 07/01/2012 04:29 AM, Thomas Sachau wrote:
>>> Matt Turner schrieb:
>>>> On Fri, Jun 29, 2012 at 10:30 AM, Thomas Sachau <tommy@g.o> wrote:
>>>>>
>>>>
>>>> I'm interested in this because I'm regularly annoyed with the emul-
>>>> packages and also because multilib is pretty important for mips.
>>>>
>>>>> If a package has dependencies, then those dependencies are required to have
>>>>> at least the same targets enabled as the package
>>>>
>>>> That seems like the obvious (but perhaps naive) choice. What about
>>>> depending on packages that don't install libraries, like x11-proto/
>>>> packages or generators like dev-util/indent?
>>>>
>>>> Maybe I just don't understand. Would these packages even have ABI flags?
>>>
>>> All packages do get the ABI flags (with the needed EAPI or via enabled
>>> portage feature, which is currently in the multilib branch).
>>>
>>> If a package does not install anything ABI-specific (no headers, no libs
>>> and no binaries), then there is no overhead, since it will just get
>>> compiled/installed for one ABI, even if multiple ABI flags are enabled.
>>
>> For a package like this that does not install anything ABI-specific,
>> does the package manager still execute phases for each enabled ABI, or
>> is there some way for the ebuild to indicate whether or not its phases
>> need to be executed for each enabled ABI?
>>
>
>
> This is dynamicly checked at runtime, no need to modify the ebuilds and
> also no needless compilation, when there is no ABI-specific content.
>
> A more detailed answer at package manager level:
> After the src_install phase for the first requested ABI has been
> finished, the content of $DESTDIR is checked. If there is no ABI
> specific content, the other enabled ABIs are skipped and the following
> steps are done as usual.

In case anyone want some more detail, here's a follow-up question from irc:

<zmedico> Tommy[D]: does any ELF executable qualify as "abi specific"
and trigger builds for all ABIs?
<Tommy[D]> zmedico: if it goes into any of /bin /usr/bin /sbin /usr/sbin
and you enable the abiwrapper USE flag, yes, otherwise you just request
a binary for the default ABI, so no need to rebuild everything for no need
-- 
Thanks,
Zac