Re: [sw-dev] Mandating that pcrel_lo and pcrel_hi stay in the same section
On 17 Apr 2019, at 19:16, Luke Kenneth Casson Leighton <lkcl@lkcl.net> wrote:
>
> Ping fwding this in case it has not been seen widely. Is it listed in bugs.debuan.org yet?
I don't see why we need a bug. As far as I'm aware, GNU ld already imposes this
restriction, and neither GCC nor LLVM generate assembly that violates this.
This is merely documenting it so that other implementations (in this case, the
LLVM backend and LLD) have an official statement that they don't need to
implement this, and can thus be simpler. What would the bug be filed against?
James
> ---------- Forwarded message ----------
> From: Palmer Dabbelt <palmer@sifive.com>
> Date: Wednesday, April 17, 2019
> Subject: [sw-dev] Mandating that pcrel_lo and pcrel_hi stay in the same section
> To: sw-dev@groups.riscv.org
>
>
> There's a proposal out on the RISC-V ELF psABI specification's github repo that is nominally an ABI change. The ABI is frozen, but we do make exceptions for cases like this where we think this quirk is unlikely to be useful and causes trouble for implementations. The full discussion can be seen here
>
> https://github.com/riscv/riscv-elf-psabi-doc/issues/90
>
> Since it's officially an ABI change I wanted to bring it up here to make sure nobody was relying on it. Given that the quirk causes binutils to fail when linking and was only found when trying to simplify LLD we think it's unlikely that any objects taking advantage of this ABI quirk exist in the wild, which is the only reason we're even considering the change in the first place.
>
> The maintainers of the various RISC-V toolchains appear to be in agreement that adding a restriction to the ABI is the right way to go, but I thought it would be good to bring up here in case someone wasn't watching github.
>
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