Downgrade linker error on protected symbols in .dynbss to a warning

[H.J. Lu]

On Fri, Apr 10, 2015 at 4:58 AM, Alan Modra <amodra@gmail.com> wrote:
> On Fri, Apr 10, 2015 at 03:49:23AM -0700, H.J. Lu wrote:
>> Adding a warning is wrong since it is OK to have copy relocation against
>> protected symbol.  It works with glibc 2.22.
>
> Not without gcc changes, and the gcc changes you posted will generate
> code that is wrong if using glibc 2.21.  Somehow you even got your

GCC 5 is no more wrong than before with older glibc.

> changes past review into gcc-5!  That's sad for gcc-5 on x86_64.

That is a matter of opinion.

>>  Totally revert my patch is
>> also wrong as indicated by tests I added since protected symbols
>> should reference globally on targets with copy relocation. It will also fail
>> the new protected symbol tests in glibc.
>
> Please show me who approved your patch in the first place.

Since my patch is limited to x86, I thought it was OK.

> I'll OK a patch that leaves the warning enabled for previous gcc code
> but disables it when detecting code that is safe to use with .dynbss
> copies of protected visibility variables.  Otherwise you are just
> hiding a real problem, as reported in PR15228.  Exactly how you detect
> the safe code is up to you.

It was about the incorrect shared library with protected symbols and
it is a run-time issue. How can linker know if the run-time shared library
is safe at link-time?

The real problem on x86 in GCC and glibc has been fixed on x86.
I will re-install my patch which is limited to x86.

-- 
H.J.