[LLVMdev] LLVM LTO

[Hal Finkel]

----- Original Message -----
> You should probably send them for review/inclusion in bfd.

Yes, I'll do that. FWIW, I imagine that further modification will be necessary for upstream acceptance (unless everything just works out okay, and I've not really tested this, some of the checks for a valid object file that the patch elides may need to be added back at some other points in order to not introduce problems with actually-invalid input files).

Thanks again,
Hal

> 
> On 11 October 2013 12:39, Hal Finkel <hfinkel at anl.gov> wrote:
> > Quick update: the previous patch only worked for static linking;
> > this version should work for both static and dynamic linking.
> >
> > I'm not going to send any more updated patches to this list, but
> > please feel free to e-mail me off-list, and I'll be happy to share
> > any updates I have at any point in the future.
> >
> >  -Hal
> >
> > ----- Original Message -----
> >> Rafael, Rui,
> >>
> >> This is obviously an old thread, but in case there is interest,
> >> I've
> >> been able to get this to work (using the LLVM gold plugin with the
> >> ld.bfd linker). This requires some additional logic in the ld.bfd
> >> linker (and a small change to the bfd library). I've attached the
> >> patch (against binutils HEAD from 2013-09-17) in case anyone finds
> >> this useful. The core issue is that ld.bfd is currently setup to
> >> use
> >> the GCC LTO plugin, which produces its IR in an ELF container, and
> >> we don't. As a result, ld.bfd needs to ask the plugin if it would
> >> like to claim files of unknown format (in addition to querying for
> >> recognized object files).
> >>
> >>  -Hal
> >>
> >> P.S. For the record, I'm certainly not a binutils expert, this
> >> just
> >> seems to work for me.
> >>
> >> ----- Original Message -----
> >> > On 1 August 2012 23:00, Sun, Rui <rui.sun at intel.com> wrote:
> >> > > Hi,
> >> > >
> >> > >
> >> > >
> >> > > I am trying to use LLVM LTO. I read
> >> > > http://llvm.org/docs/GoldPlugin.html and
> >> > > have some questions. Could anyone help?
> >> > >
> >> > >
> >> > >
> >> > > 1.       Can LLVMgold.so work with BFD LD instead of gold? In
> >> > > the
> >> > > description of changes in binutils 2.20, “* The plugin target
> >> > > has
> >> > > been added
> >> > > to bfd. It can load the same shared objects
> >> > >
> >> > > used by gold and uses them to provide basic support for new
> >> > > file
> >> > > formats.”.
> >> > > Does this mean BFD LD after 2.20 can support LLVMgold.so?  Ld
> >> > > version on my
> >> > > system is:
> >> > >
> >> > > GNU ld (GNU Binutils for Ubuntu) 2.21.53.20110810
> >> > >
> >> >
> >> > In theory it can, but I think it is completely untested.  I
> >> > think
> >> > that, as with gold, you have to build it with --enable-plugins.
> >> >
> >> > >
> >> > > 2.       Gold only supports ELF. If BFD LD can support
> >> > > LLVMgold,
> >> > > can LTO be
> >> > > applied to COFF objects after recompiling the binutils with
> >> > > target==x86_64-pc-pe?
> >> >
> >> > Double untested, but I guess it could be made to work :-)
> >> >
> >> > >
> >> > > Thanks!
> >> > >
> >> > > Rui
> >> > >
> >> > >
> >> >
> >> > Cheers,
> >> > Rafael
> >> >
> >> > _______________________________________________
> >> > LLVM Developers mailing list
> >> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> >> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >> >
> >>
> >> --
> >> Hal Finkel
> >> Assistant Computational Scientist
> >> Leadership Computing Facility
> >> Argonne National Laboratory
> >
> > --
> > Hal Finkel
> > Assistant Computational Scientist
> > Leadership Computing Facility
> > Argonne National Laboratory
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory