Re: From LLVM: I got a note that LLVM plans to remove PPC64's V1 abi support; I'm asked about what support there is for the PPC64 little-endian/V2 abi (see forwarded message)

From: Justin Hibbits <chmeeedalf_at_gmail.com>
Date: Wed, 28 Mar 2018 15:34:00 -0500
On Wed, Mar 28, 2018 at 3:17 PM, A. Wilcox <AWilcox_at_wilcox-tech.com> wrote:
> On 03/28/18 13:38, Nathan Whitehorn wrote:
>> Is this big-endian support or V1 support being removed? We support
>> the V2 ABI fully on FreeBSD, but not (yet) little-endian. Like on
>> Linux, the default ABI on big-endian will likely remain V1 for the
>> indefinite future,
>
> This is an important distinction to make (big-endian != ELFv1, and ELFv1
> != big-endian).
>
> But do note that on Linux, the musl libc (in use by distros like Alpine,
> Adélie, postmarketOS) only supports ELFv2, even in big-endian mode.  And
> as the maintainer of Adélie using it as a daily-driver on an iMac G5,
> it's definitely something you can use (the only breakage I've seen so
> far on Linux is the PCRE JIT ignoring __CALL_ELF and inserting function
> descriptors anyway).
>
> So I wouldn't discount moving to ELFv2 ABI on BE if that is necessary to
> keep LLVM happy.  It'd be some effort but it should work.
>
> If this is really something FreeBSD is interested in, you might even
> manage to convince me to put on my ports hat again, to help get the JIT
> patches in that are needed for upstreams that went comatose.
>
>
> Best,
> --arw
>
>
>> however, and it would be good if it were at least simple to re-add
>> support at some later date. -Nathan
>>
>
> --
> A. Wilcox (awilfox)
> Open-source programmer (C, C++, Python)
> https://code.foxkit.us/u/awilfox/
>

Moving to ELFv2 is predicated on having a complete toolchain
supporting it.  Right now, base gcc+binutils only supports ELFv1, and
we cannot upgrade to newer toolchain yet.

- Justin
Received on Wed Mar 28 2018 - 18:34:03 UTC

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