lld status with powerpc64
Bill Schmidt
wschmidt@linux.ibm.com
Mon Nov 8 13:26:21 GMT 2021
On 11/8/21 5:37 AM, Adhemerval Zanella wrote:
>
> On 07/11/2021 11:24, Bill Schmidt wrote:
>> Please coordinate with Alan Modra and Nemanja Ivanovic on this topic. There are ongoing discussions about bfd and lld linker support around @notoc that will be resolved soon, and Tulio is on vacation, so I don't want the community to make steps they'll have to undo later, or for people to engage in duplicate work.
> For this specific issue I just sent a patch to fix it on glibc side [1].
> However I think it would be good if lld also implements the ld.bfd
> optimization to fallback to older stub generation if no pcrel relocation
> is found (although it is debatable that @notoc should implicit generate
> older ISA code depending of the resulting objects being linked against).
>
> [1] https://patchwork.sourceware.org/project/glibc/patch/20211108113316.8867-1-adhemerval.zanella@linaro.org/
Hi Adhemerval,
Current course and speed is that @notoc will imply pcrel stubs on P10 and later,
but will not do so on P9 and earlier. The relocation currently associated with
@notoc actually came with ELFv2 on P8 and, although no compilers ever generated
@notoc, assembly routines using it prior to P10 are a valid case and should not be
punished. This can be handled by generating a different reloc for @notoc in the
two cases.
If this solution holds up, then changes to glibc should be unnecessary.
Thanks,
Bill
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