[llvm] r273019 - Change RelaxELFRelocations for llc.

[Sean Silva via llvm-commits]

On Tue, Jun 21, 2016 at 10:07 AM, Rafael Espíndola <
llvm-commits at lists.llvm.org> wrote:

> .
> >
> > I wouldn't mind if the default simply stayed "false", like it was in the
> past for everything but those tools that can know it's safe. But, if
> there's going to be any a default of using the new relocs in other
> circumstances, I think that must be guarded behind the off-by-default cmake
> flag, for now. Even for the developer tools. Probably in a couple years
> from now it'll be safe to change the global default without breaking
> anything, but it's really not, now...
>
> If we don't change the default in the library, tool writers are not likely
> to find out that there are new relocations out there and we will be having
> exactly the same discussion a couple of years from now.
>
Is there any ELF system linker whose most recent version doesn't support
the new relocations? From what I can tell it is just a matter of time until
all linkers in common use support the relocations. So I disagree that "we
will be having exactly the same discussion a couple of years from now".
Most likely a couple years from now there will be general support.



> If we change the library default each tool will find out about it when
> they upgrade, trivially disable  it and in the future we will be able to
> check if anyone is still depending on it.
>

I think you're seriously underestimating how much time may be consumed
between seeing a random linker failure and tracing it down to the fix. I
don't think it is anywhere near "trivial". Also a person experiencing the
issue may not be in a position to fix or understand the problem (for
example, the person running into the issue is not one of the core
developers of the tool or is new to the tool and unfamiliar with LLVM).

-- Sean Silva

> Cheers,
> Rafael
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160621/f4f15809/attachment.html>