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

["Anthony G. Basile" <blueness@gentoo.org>]

On 12/29/2013 05:33 PM, Markos Chandras wrote:
> 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.
>
Or their maintaining lots-o-patches which is what starts to happen when 
you deviate from standards.  Anyhow, we should talk to them and see.

-- 
Anthony G. Basile, Ph.D.
Gentoo Linux Developer [Hardened]
E-Mail    : blueness@gentoo.org
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