[llvm-dev] [flang-dev] Re: Adapting and open-sourcing PGI's Fortran frontend for LLVM

Fri May 27 10:48:57 PDT 2016

----- Original Message -----
> From: "C Bergström" <cbergstrom at pathscale.com>
> To: "Rob Neely" <neely4 at llnl.gov>
> Cc: "Mehdi Amini" <mehdi.amini at apple.com>, "Pat McCormick" <pat at lanl.gov>, llvm-dev at lists.llvm.org, "Mike Heroux"
> <maherou at sandia.gov>, "flang-dev" <flang-dev at googlegroups.com>, "douglas miles (PGI)" <douglas.miles at pgroup.com>
> Sent: Friday, May 27, 2016 4:21:16 AM
> Subject: [flang-dev] Re: [llvm-dev] Adapting and open-sourcing PGI's Fortran frontend for LLVM
> 
> This process is certainly only open to a select group, so
> pragmatically it's closed. I can understand that it will certainly
> not
> be an easy process once it's public due to the amount of code and
> complexity.
> 
> Maybe someone can comment on a specific issue -
> 
> When we ported our Fortran front-end to target llvm, we found that
> Fortran ENTRY doesn't map very well to llvm ir.
> 
> Can anyone who is actually working on this migration comment how they
> plan to handle that?
> ENTRY docs
> http://docs.oracle.com/cd/E19957-01/805-4939/6j4m0vn99/
> 
> ENTRY is I think officially deprecated, but dinosaurs won't nuke
> anything, ever.. (It's still used in the wild as well... ugh)

How do you handle it? Is there any reason we can't just generate one function body per entry point? Where these might call some internal implementation function which takes a hidden argument that feeds an initial jump table.

> 
> /* btw for anyone actually reading this - I think it's odd that
> nobody
> has emailed me to ask for help reviewing. I must have thought wrongly
> that everyone around here knows we (PathScale) ported Fortran to LLVM
> IR since 5 years.. */

Lot's of people are reading ;) -- Thanks for volunteering! I don't think that we've really put together the external reviewers on DOE's side of things, but please do contact the PGI folks out-of-band about early access to provide feedback.

Thanks again,
Hal

> -------------
> I'm not sure if I asked before, but will any corresponding tests be
> open sourced as well? I know of a handful of private Fortran
> testsuites, but not much in the way of public.. (gfortran is about
> the
> only game which comes to mind)
> 
> 
> On Fri, May 27, 2016 at 5:32 AM, Neely, Rob via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> > No closed doors intended here. Just a recognition that for
> > something like
> > an initial review to be useful, we probably have to be a bit
> > careful in
> > how many people we can reasonably involve before it could get
> > unwieldy,
> > and trying to be respectful of people’s time if we can nail down
> > 90% of
> > issues with a smaller group before going broader. I think we’d be
> > fine
> > with opening up the WebEx presentations to whoever wanted to
> > observe and
> > possibly chime in if it could be a managed process.
> >
> > —Rob
> >
> >
> > On 5/26/16, 2:06 PM, "mehdi.amini at apple.com on behalf of Mehdi
> > Amini"
> > <mehdi.amini at apple.com> wrote:
> >
> >>
> >>> On May 26, 2016, at 1:57 PM, Neely, Rob via llvm-dev
> >>><llvm-dev at lists.llvm.org> wrote:
> >>>
> >>> Chad, et al,
> >>>
> >>> In addition to Doug’s excellent technical update, I’ll note that
> >>> we are
> >>> starting to have some discussions on the DOE side with PGI about
> >>> establishing a more formal review team made up of some key LLVM
> >>> stakeholders to help smooth the way for a broader public rollout
> >>> of the
> >>> Flang code base and eventual integration. We’ll probably rely on
> >>> Hal and
> >>> others here to help us figure out who that group might be. My
> >>>expectation
> >>> is that it would involve a few WebEx/telecons on an as-needed
> >>> basis
> >>> (perhaps quarterly?) starting later this summer when code starts
> >>> to move
> >>> out of PGI’s internal systems and into a private github space.
> >>> Stay
> >>>tuned
> >>> - we (both DOE and PGI) are keenly interested in doing what we
> >>> can to
> >>>make
> >>> this successful.
> >>
> >>It seems to me that this "let's do it with selected people behind
> >>close
> >>doors" does not play well with "we are seeking to have some
> >>integration
> >>in the open-source projects and its broaden community".
> >>My own personal impression is that not conducting it in the open
> >>blurs
> >>the "message" around Flang direction and goals.
> >>
> >>--
> >>Mehdi
> >>
> >>
> >>>
> >>> —Rob Neely, LLNL
> >>>
> >>>
> >>> On 5/26/16, 11:57 AM, "douglas miles (PGI)"
> >>> <douglas.miles at pgroup.com>
> >>> wrote:
> >>>
> >>>
> >>>> Hi Chad - We have a functional Fortran compiler, with the PGI
> >>>> front-end
> >>>> bridged directly to LLVM, all of our Fortran runtime libraries
> >>>> integrated, and the Clang driver adapted for use with the
> >>>> Fortran
> >>>> compiler.  We're working with a few users at DOE who are trying
> >>>> to
> >>>> compile big applications with a binary version of the compiler.
> >>>>  Work
> >>>>is
> >>>> ongoing to migrate the source code into an LLVM-style
> >>>> repository, build
> >>>> infrastructure, documentation and web pages.  All of the
> >>>> compiler and
> >>>> runtime source is now built with Clang or the Fortran front-end
> >>>> with
> >>>> LLVM.  Much work remains on source code refactoring and
> >>>> documentation;
> >>>> we expect that work to accelerate once all the infrastructure
> >>>> work is
> >>>> done.
> >>>>
> >>>> Doug
> >>>>
> >>>> -----Original Message-----
> >>>> From: Hal Finkel [mailto:hfinkel at anl.gov]
> >>>> Sent: Thursday, May 26, 2016 9:17 AM
> >>>> To: mcrosier at codeaurora.org
> >>>> Cc: flang-dev; douglas miles (PGI); Rob Neely; Chris Lattner;
> >>>> llvm-dev at lists.llvm.org
> >>>> Subject: Re: [llvm-dev] Adapting and open-sourcing PGI's Fortran
> >>>>frontend
> >>>> for LLVM
> >>>>
> >>>> Hi Chad,
> >>>>
> >>>> I can tell you that progress is being made on PGI's side; I'll
> >>>> let
> >>>> Doug/Rob provide more detailed updates.
> >>>>
> >>>> -Hal
> >>>>
> >>>> ----- Original Message -----
> >>>>> From: "Chad Rosier" <mcrosier at codeaurora.org>
> >>>>> To: "Hal Finkel" <hfinkel at anl.gov>
> >>>>> Cc: "flang-dev" <flang-dev at googlegroups.com>, "douglas miles
> >>>>> (PGI)"
> >>>>> <douglas.miles at pgroup.com>, "Rob Neely"
> >>>>> <neely4 at llnl.gov>, "Chris Lattner" <clattner at apple.com>,
> >>>>> llvm-dev at lists.llvm.org
> >>>>> Sent: Thursday, May 26, 2016 10:47:19 AM
> >>>>> Subject: RE: [llvm-dev] Adapting and open-sourcing PGI's
> >>>>> Fortran
> >>>>> frontend   for     LLVM
> >>>>>
> >>>>> Hi Hal,
> >>>>> I haven't been following this closely, but has there been any
> >>>>> updates
> >>>>> recently.
> >>>>>
> >>>>> Regards,
> >>>>>  Chad
> >>>>>
> >>>>> -----Original Message-----
> >>>>> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On
> >>>>> Behalf Of
> >>>>> Chris Lattner via llvm-dev
> >>>>> Sent: Sunday, November 15, 2015 12:46 AM
> >>>>> To: Hal Finkel <hfinkel at anl.gov>
> >>>>> Cc: LLVM Dev <llvm-dev at lists.llvm.org>; flang-dev
> >>>>> <flang-dev at googlegroups.com>; douglas miles (PGI)
> >>>>> <douglas.miles at pgroup.com>; Rob Neely <neely4 at llnl.gov>
> >>>>> Subject: Re: [llvm-dev] Adapting and open-sourcing PGI's
> >>>>> Fortran
> >>>>> frontend for LLVM
> >>>>>
> >>>>>
> >>>>>> On Nov 13, 2015, at 2:22 PM, Hal Finkel via llvm-dev
> >>>>>> <llvm-dev at lists.llvm.org> wrote:
> >>>>>>
> >>>>>> Hi everyone,
> >>>>>>
> >>>>>> I have some very good news for everyone interested a
> >>>>>> production-quality Fortran frontend for LLVM:
> >>>>>>
> >>>>>> The U.S. Department of Energy’s National Nuclear Security
> >>>>>> Administration and its three national labs have reached an
> >>>>>> agreement
> >>>>>> with NVIDIA's PGI division to adapt and open-source PGI's
> >>>>>> Fortran
> >>>>>> frontend, and associated Fortran runtime library, for
> >>>>>> contribution
> >>>>>> to the LLVM project. PGI is now working on isolating the
> >>>>>> necessary
> >>>>>> frontend components from their existing compiler code base and
> >>>>>> adapting those components to produce LLVM IR for consumption
> >>>>>> by our
> >>>>>> existing infrastructure.
> >>>>>
> >>>>> This sounds very interesting Hal (and Doug), and I’m glad to
> >>>>> hear
> >>>>> about it.  I look forward to when more details and code is
> >>>>> available,
> >>>>>
> >>>>> -Chris
> >>>>> _______________________________________________
> >>>>> LLVM Developers mailing list
> >>>>> llvm-dev at lists.llvm.org
> >>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>>>>
> >>>>>
> >>>>
> >>>> --
> >>>> Hal Finkel
> >>>> Assistant Computational Scientist
> >>>> Leadership Computing Facility
> >>>> Argonne National Laboratory
> >>>>
> >>>>
> >>>>------------------------------------------------------------------------
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> >>>> is prohibited.  If you are not the intended recipient, please
> >>>> contact
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> >>>> sender by
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> >>>>
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> >>>>--
> >>>> ---------
> >>>
> >>> _______________________________________________
> >>> LLVM Developers mailing list
> >>> llvm-dev at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >
> > _______________________________________________
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-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory