This is the mail archive of the mailing list for the binutils project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [RFC][PATCH] Check ELF relocs after opening all all input files

On Wed, Apr 20, 2016 at 08:54:57AM +0930, Alan Modra wrote:
> On Tue, Apr 19, 2016 at 11:03:15AM -0700, H.J. Lu wrote:
> > On Tue, Apr 19, 2016 at 9:01 AM, Nick Clifton <> wrote:
> > > Hi H.J.
> > >
> > >> Delaying checking ELF relocations until opening all input files so
> > >> that symbol information is final when relocations are checked.  This
> > >> is only enabled for x86 targets.
> > >
> > >> Any comments, feedbacks?
> > >
> > > What benefit is gained by doing this ?  I would guess that it is connected
> > > with symbols changing type and/or visibility and/or protected status, but
> > > it would be nice to know what you are hoping to achieve.
> > 
> > Yes,  this change is motivated by that discussion.  Currently backend
> > check_relocs doesn't have the final information on symbols.  A better
> > linker can provide better diagnostics in check_relocs if symbol info is
> > final.
> There are other benefits too.  As it is the backend check_relocs
> functions do things like "maybe this symbol remains undefined so
> perhaps it needs a plt entry", and "maybe this symbol remains dynamic
> so perhaps it needs dynamic relocations".  This complexity can
> disappear if all of those "maybe" cases are resolved.
> Now, if you run check_relocs even later, say at
> ldemul_before_allocation, after gc-sections has run, then all the
> reference counting code for plt and got relocs can be removed too.

Sounds nice! This would probably have avoided bug #19516 ever


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]