From: Alan Modra <amodra@bigpond.net.au>
To: "H. J. Lu" <hjl@lucon.org>
Cc: binutils@sources.redhat.com
Subject: Re: RFC: -Bsymbolic, hidden and protected
Date: Thu, 03 Mar 2005 21:54:00 -0000 [thread overview]
Message-ID: <20050303215444.GF376@bubble.modra.org> (raw)
In-Reply-To: <20050303165510.GA10048@lucon.org>
On Thu, Mar 03, 2005 at 08:55:10AM -0800, H. J. Lu wrote:
> On Thu, Mar 03, 2005 at 07:55:04AM -0800, H. J. Lu wrote:
> > On Thu, Mar 03, 2005 at 11:19:13PM +1030, Alan Modra wrote:
> > > On Wed, Mar 02, 2005 at 08:14:59PM -0800, H. J. Lu wrote:
> > > > Protected visibility has almost everything, but requires
> > > > special handling at run-time.
> > > >
> > > > I was wondering if we could allow version script to overwrite
> > > > hidden symbols. That is if a symbol is global in version script, we
> > > > export it even if it is marked hidden. It may improve run-time
> > > > performance.
> > >
> > > How is this going to be different from using protected symbols?
> >
> > No run-time special handling accociated with protected symbols, which
> > may take extra lookup.
>
> Also compiler/linker can't optimize protected function pointers.
Which means that if you export hidden function symbols from shared
libraries by means of a version script, you will break function pointer
comparisons.
--
Alan Modra
IBM OzLabs - Linux Technology Centre
next prev parent reply other threads:[~2005-03-03 21:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-03 4:15 H. J. Lu
2005-03-03 12:49 ` Alan Modra
2005-03-03 15:55 ` H. J. Lu
2005-03-03 16:55 ` H. J. Lu
2005-03-03 21:54 ` Alan Modra [this message]
2005-03-04 1:37 ` H. J. Lu
2005-04-21 21:06 ` PATCH: Force a hidden symbol global H. J. Lu
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