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>:>> 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
On Apr 19, 2012, at 9:29 AM, Dmitry N. Mikushin <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.As far back as the LLVM 2.8, the release notes have included this warning: "The C backend has numerous problems and is not being actively maintained. Depending on it for anything serious is not advised." It had, in fact, been non-functional for all but non-trivial functions for much longer than that. Nobody had ever stepped up to actually fix it, despite various people saying they wanted it to it. We're not interested in having non-working code hanging around in LLVM, misleading users as to the actual usability of the feature. If you want to contribute (and maintain!) a *working* C backend, have at it! --Owen
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> 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>: >>> 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 > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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>:> 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> 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>: >>>> 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 >> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >