[LLVMdev] CBackend removal

Fri Apr 20 09:21:58 PDT 2012

Hi, 

First of all, I agree in some level that is not good for a production tool as LLVM having features that do not work properly. Actually it should be really annoying if anyone adopted LLVM only because of its non-functional passes, but, as Owen said, the CBackend pass was working for trivial functions, which is, in some cases, only what some person needs. In other words, I agreed that tools as CBackend should not be distributed inside final versions of LLVM, but I also agree that, even not totally functional, it is an interesting feature of LLVM.

And, sorry, Dmitry, for the late reply: actually, I'm in need of the CBackend and the profiling in LLVM as a basic infrastructure for my project. (Yep, apparently I'm so luck that I need exactly the tools that are not in their better days). In this moment, I'm trying to get a minimum profile information for my pass, just to see how it could work. I'm really interested in the CBackend, but as it seams it is the last pass I'm gonna use, I can't invest time on it right now. But I'll let you know when I get there =)

Sincerely, 

-- 
Cristianno Martins
PhD Student of Computer Science
University of Campinas
cmartins at ic.unicamp.br

On Thursday, 19 de April de 2012 at 15:28, Dmitry N. Mikushin wrote:

> Dear Jim and Owen,
> 
> Thanks for replies,
> 
> I only kindly suggest some discussion on the maillist in such cases.
> Just in general, nasty precedents sometimes happen, for example on IRC
> I've recently seen some commits to Objective C were requested to be
> reverted, because they were commited without any discussion. Here
> things are certainly not that hard, but the point is the same: it is
> always nice to put a FYI, because it might help a lot of non-core
> people to properly align their work and prevent late complains.
> 
> To be constructive, I would like to contribute patches to make C
> backend usable. Last time I tried is here:
> http://lists.cs.uiuc.edu/pipermail/llvmdev/2011-August/042243.html But
> my tests are meaningless and specific. It would be perfect to find
> other devs who can contribute test suites. So, I'll give patches, you
> - tests. Let's team up! Cristianno, are you interested?
> 
> - D.
> 
> 2012/4/19 Jim Grosbach <grosbach at apple.com (mailto:grosbach at apple.com)>:
> > Hi Dmitry,
> > 
> > Where were you expecting notice to have been given? If I recall correctly, the obsolescence of the C backend was mentioned many times on this mailing list, and as Owen notes, in the release notes since 2.8. I'm not trying to be snarky. You were obviously genuinely surprised by its removal, and that makes me wonder if where the core open source devs are expecting people to look for that kind of information isn't lining up with where people actually are looking.
> > 
> > -Jim
> > 
> > On Apr 19, 2012, at 9:29 AM, Dmitry N. Mikushin <maemarcus at gmail.com (mailto:maemarcus at gmail.com)> wrote:
> > 
> > > Dear all,
> > > 
> > > I've also noticed C backend was removed a little bit... silently. In
> > > the end of March I only got open bugs closed by Benjamin Kramer in
> > > bugzilla, but they sounded like "decision is made". So the question
> > > is: it such silent removal a normal practice? In times of 3.0 release
> > > there were long discussions on what to drop and what to preserve, e.g.
> > > sparc backend, if I remember correctly.
> > > 
> > > In our project we are very interested in maintaining usable C backend,
> > > at least until there will be at least one full and production quality
> > > PTX backend.
> > > 
> > > Best regards,
> > > - Dima
> > > 
> > > 2012/4/19 Anton Korobeynikov <anton at korobeynikov.info (mailto:anton at korobeynikov.info)>:
> > > > > I'm periodically updating my local version of the LLVM, and, when I did it
> > > > > today, I couldn't use the llc with -march=c. Looking for the CBackend files,
> > > > > I realized that they were removed from the LLVM folder. I actually don't
> > > > > remember reading about a drop of this capability in any of the devlist
> > > > > messages, so I was wondering if this removal could be only temporary, or
> > > > > there will be no more support for this feature in LLVM.
> > > > > 
> > > > 
> > > > CBackend was broken in many ways and thus removed. Patches to
> > > > introduce shiny new CBackend are welcome :)
> > > > 
> > > > --
> > > > With best regards, Anton Korobeynikov
> > > > Faculty of Mathematics and Mechanics, Saint Petersburg State University
> > > > _______________________________________________
> > > > LLVM Developers mailing list
> > > > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> > > > 
> > > 
> > > 
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> > > 
> > 
> > 
> 
> 
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