This is the mail archive of the
mailing list for the GCC project.
Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248]
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: Cary Coutant <ccoutant at gmail dot com>, Michael Matz <matz at suse dot de>, "Maciej W. Rozycki" <macro at imgtec dot com>, Alan Modra <amodra at gmail dot com>, Richard Biener <richard dot guenther at gmail dot com>, Joe Groff <jgroff at apple dot com>, Binutils <binutils at sourceware dot org>, GCC <gcc at gcc dot gnu dot org>
- Date: Mon, 25 Apr 2016 10:31:50 -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: <983472E1-A1BC-4970-9CF9-0138A6BAD16D at apple dot com> <CAMe9rOqTTwirymAY6ORp6D_GnCsMc_hYEdy1NbZpG6x5vQc5DQ at mail dot gmail dot com> <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> <alpine dot DEB dot 2 dot 00 dot 1604181631420 dot 21846 at tp dot orcam dot me dot uk> <CAMe9rOoxb2RKQ3ELPu=omSxnLnH326tyXpAPkZ8G+t8edSGuxw at mail dot gmail dot com> <alpine dot LSU dot 2 dot 20 dot 1604181918110 dot 20277 at wotan dot suse dot de> <CAJimCsHLxxED8we1YHMnnz5=JNFoZEeY2fgg9VPPuP0xBXK8vQ at mail dot gmail dot com> <18662de1-62db-2b44-ef50-2c04204e2521 at redhat dot com>
On Mon, Apr 25, 2016 at 10:24 AM, Jeff Law <email@example.com> wrote:
> On 04/18/2016 11:55 AM, Cary Coutant wrote:
>>>> That is why protected visibility is such a mess.
>>> Not mess, but it comes with certain limitations. And that's okay. It's
>>> intended as an optimization, and it should do that optimization if
>>> requested, and error out if it can't be done for whatever reason.
>> I completely agree.
> ISTM this ought to be the guiding principle here, with the additional caveat
> that if one of the limitations is tickled that we issue a good diagnostic.
> The current situation (gcc-5, gcc-6-rc) essentially de-optimizes protected
> systems in an attempt to work around the various limitations of protected
> symbols. Reverting that change is, IMHO, what needs to happen. My worry is
> that we're so damn late in the gcc-6 cycle that it may need to be deferred
> to 6.2 or beyond.
Please keep in mind that many limitations can only be detected at
link-time or run-time, which are yet to be implemented, not at