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

["Anthony G. Basile" <basile@opensource.dyc.edu>]

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.

-- 
Anthony G. Basile, Ph. D.
Chair of Information Technology
D'Youville College
Buffalo, NY 14201
(716) 829-8197