This is the mail archive of the
mailing list for the binutils project.
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
- References: <6AAD87D2-90F9-4AD7-A195-AC91B76EA6AE at apple dot com> <CAMe9rOqNcYnm1YocG-m7XNDE0g68YQAGe=ULP-G98gaatpxSeA at mail dot gmail dot com> <CAJimCsHfT=cfb4kZysB2W_1HFfOq==TpP=wa47XPGB41MHmGyQ at mail dot gmail dot com> <56FB5061 dot 9010303 at redhat dot com> <20160330143421 dot GM15812 at bubble dot grove dot modra dot org> <571161D0 dot 10601 at redhat dot com> <CAMe9rOpt2Fd6RLtjr10wCHz9PVsXxtO9a0yvMR_DeHt1OK0ieg at mail dot gmail dot com> <CAFiYyc2PFQdiUj=UPY8HLv+PjwVaNpcvDW6Skp8JC4DR56MkBg at mail dot gmail dot com> <20160418144911 dot GG15088 at bubble dot grove dot modra dot org> <CAMe9rOog=FJ2Si-mUqHYoOsHVwVFcZavT4X7wQdRjRhbDDWRvQ at mail dot gmail dot com> <20160419050805 dot GI15088 at bubble dot grove dot modra dot org> <CAFiYyc1NJD0LAW2Mxe+xdgizTd3j7A9gwHEzHJA3A+hWpDO+Ew at mail dot gmail dot com> <alpine dot LSU dot 2 dot 20 dot 1604191603210 dot 20277 at wotan dot suse dot de>
>> 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: