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

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

On 12/29/2013 05:13 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.  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.

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