[PATCH] D92445: [PowerPC] Add powerpcle target.

Tue Dec 1 20:08:31 PST 2020

Bdragon28 added a comment.

In D92445#2427537 <https://reviews.llvm.org/D92445#2427537>, @Bdragon28 wrote:

> In D92445#2427438 <https://reviews.llvm.org/D92445#2427438>, @nemanjai wrote:
>
>> This seems problematic to me for a few reasons:
>>
>> 1. There is no 32-bit toolchains or libraries for little endian Linux systems
>> 2. There is no support in the ELFv2 ABI for 32-bit object mode and there may be a number of places we assume that little endian systems use ELFv2 ABI
>> 3. There are a number of places that make the assumption that little endian systems must be 64-bit so there's no checking for 32-bit mode (which will likely result in 64-bit specific code gen)
>>
>> Since this seems to be for a very specific use case, can we perhaps severely restrict the support for 32-bit little endian mode (perhaps BSD only, no Altivec/VSX, etc.)?
>
> Technically, 32 bit PowerPC systems are neither ELFv1 nor ELFv2, they are Power Architecture 32-bit ABI (which has various extensions) that does not have the complexities that plagued ELFv1 and is a relatively "normal" ABI.
>
> I have not seen any places that this is problematic that I am not already addressing with this patch.

I would be fine with restricting this to FreeBSD and/or limiting it to freestanding. I mainly added the Linux support as there was recent interest in 32-bit LE and it is a possibility there will be some experimental userlands at some point in the future. https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-May/211669.html

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