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Re: PATCH: Use x86_64 bits/environments.h for both i386 and x86_64


On Thu, May 31, 2012 at 4:39 PM, Roland McGrath <roland@hack.frob.com> wrote:
>> That is true. ?However, ILP32 here means -m32, not -mx32.
>> POSIX only supports LP64 (-m64) and ILP32 (-m32). ?There
>> is nothing for -mx32.
>
> cf http://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html
>
> POSIX doesn't say that any of the variants have to be mutually compatible.
> x32 meets the requirements of _POSIX_V7_ILP32_OFFBIG.
> So __ILP32_OFFBIG_{C,LD}FLAGS could be -mx32.
>
> It also says that additional environments could be supported, beyond those
> that are listed in the standard. ?So _CS_V7_WIDTH_RESTRICTED_ENVS could
> yield an additional name we choose. ?Then that new name could correspond to
> -mx32, or _POSIX_V7_ILP32_OFFBIG could correspond to -mx32 and the new name
> to what _POSIX_V7_ILP32_OFFBIG means today.
>
> It's not clear adding an additional nonstandard name is particularly
> useful, since it seems unlikely anything would ever request it.
>
> Leaving things as they are is almost certainly the wisest thing to do, at
> least for now. ?But if a POSIX-compliant application really just wants
> _POSIX_V7_ILP32_OFFBIG because it is not 64-bit clean yet cares about big
> files, having that produce -mx32 on an x86_64 system would mean that this
> application gets built to the most efficient ABI it can handle (presuming
> x32 is more efficient than i386, which is the point of it).
>

I will take a look. I may have a patch somewhere.  Let me see if I can find it.

Thanks.

-- 
H.J.


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