Re: [gentoo-mips] Re: On MIPS using the same CHOST for all multilib ABIs

[Markos Chandras <hwoarang@gentoo.org>]

On 12/29/2013 10:19 PM, Anthony G. Basile wrote:
> On 12/29/2013 05:13 PM, Markos Chandras wrote:
>> On 12/29/2013 09:52 PM, Anthony G. Basile wrote:
>>> On 12/29/2013 04:48 PM, Markos Chandras wrote:
>>>> On 12/29/2013 09:48 PM, Michał Górny wrote:
>>>>> Dnia 2013-12-29, o godz. 16:40:08
>>>>> Joshua Kinard <kumba@gentoo.org> napisał(a):
>>>>>
>>>>>> On 12/28/2013 5:58 PM, Michał Górny wrote:
>>>>>>> I've noticed today that mips uses the same CHOST value for all three
>>>>>>> ABIs it supports:
>>>>>>>
>>>>>>> arch/mips/mips64/multilib/make.defaults:CHOST_o32="${CHOST}"
>>>>>>> arch/mips/mips64/multilib/make.defaults:CHOST_n32=${CHOST}
>>>>>>> arch/mips/mips64/multilib/make.defaults:CHOST_n64=${CHOST}
>>>>>>> arch/mips/mipsel/mips64el/multilib/make.defaults:CHOST_o32="${CHOST}"
>>>>>>>
>>>>>>> arch/mips/mipsel/mips64el/multilib/make.defaults:CHOST_n32="${CHOST}"
>>>>>>>
>>>>>>> arch/mips/mipsel/mips64el/multilib/make.defaults:CHOST_n64="${CHOST}"
>>>>>>>
>>>>>>>
>>>>>>> [...]
>>>>>> Matt can probably vouch for this better, but the only two ABIs
>>>>>> affected by
>>>>>> this are n32 and n64.  mips[el]-unknown-linux-gnu implies a 32-bit
>>>>>> big/little endian CHOST, which means the o32 ABI.
>>>>>> mips64[el]-unknown-linux-gnu means either n32 or n64.  So no change
>>>>>> should
>>>>>> be needed for o32-based installs.
>>>>> Just to be clear:
>>>>>
>>>>> profiles/arch/mips/mipsel/mips64el/multilib/make.defaults:
>>>>>
>>>>> CHOST="mips64el-unknown-linux-gnu"
>>>>>
>>>>> [...]
>>>>>
>>>>> CFLAGS_o32="-mabi=32"
>>>>> CHOST_o32="${CHOST}"
>>>>>
>>>>> CFLAGS_n32="-mabi=n32"
>>>>> CHOST_n32="${CHOST}"
>>>>>
>>>>> CFLAGS_n64="-mabi=64"
>>>>> CHOST_n64="${CHOST}"
>>>>>
>>>>> So in this case, o32 actually uses mips64el-unknown-linux-gnu, unless
>>>>> I'm missing something.
>>>>>
>>>> Yes all 3 ABIs use the same tuple.
>>>>
>>> I think people are missing Mike's point from earlier, which is that
>>> tuples label toolchains and a toolchain can support multiple abis.  So
>>> for example, what would one do on a system which simultaneously has o32,
>>> n32 and n64?  -gnuabi32n32n64 looks pretty crazy.
>>>
>> There is only one default ABI, so the toolchain should be named after
>> that. But that does not mean the toolchain can't build for different ABIs
>>
> No because that would confuse a toolchain which only supports n32 with
> one that supports o32/n32/n64.
Ah fair point

  Anyhow, Michał response is heading in
> the right direction where we'd have to use multiple tuple on multilib
> system support more than one lib.  I'm still not sure where this will
> land us with respect to gnuconfig and other tuple parsing tools that
> bring in their own assumptions.
> 
I would guess that if debian is using the -gnuabin32/64 suffix and it
works for them, then such tools would already understand such tuples.

-- 
Regards,
Markos Chandras