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Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248]
- From: Cary Coutant <ccoutant at gmail dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: Richard Biener <richard dot guenther at gmail dot com>, Alan Modra <amodra at gmail dot com>, "H.J. Lu" <hjl dot tools at gmail dot com>, Jeff Law <law at redhat dot com>, Joe Groff <jgroff at apple dot com>, Binutils <binutils at sourceware dot org>, GCC <gcc at gcc dot gnu dot org>
- Date: Tue, 19 Apr 2016 08:37:27 -0700
- Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248]
- Authentication-results: sourceware.org; auth=none
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>> So with all this it sounds that current protected visibility is just
>> broken and we should forgo with it, making it equal to default
> Like how? You mean in GCC regarding protected as default visibility? No,
> that's just throwing out the baby with the water. We should make
> protected do what it was intended to do and accept that not all invariants
> that are true for default visible symbols are also true for protected
> symbols, possibly by ...
>> At least I couldn't decipher a solution that solves all of the issues
>> with protected visibility apart from trying to error at link-time (or
>> runtime?) for the cases that are tricky (impossible?) to solve.
> ... this.
Right. Protected visibility worked fine without copy relocations for
15 years until HJ's patch. I don't know of anyone with a legitimate
complaint about that until HJ filed a bug based on his artificial test
Other compilers implement protected the way it was intended, so the
linkers must still disallow copy relocations against protected
symbols, or we get legitimate complaints like these: