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Open Source Programming

LLVM 3.5 Brings C++1y Improvements, Unified 64-bit ARM Backend 99

An anonymous reader writes: LLVM 3.5 along with Clang 3.5 are now available for download. LLVM 3.5 offers many compiler advancements including a unified 64-bit ARM back-end from the merging of the Apple and community AArch64 back-ends, C++1y/C++1z language additions, self-hosting support of Clang on SPARC64, and various other compiler improvements.
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LLVM 3.5 Brings C++1y Improvements, Unified 64-bit ARM Backend

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  • Oh good. (Score:3, Insightful)

    by i kan reed ( 749298 ) on Friday September 05, 2014 @04:10PM (#47837749) Homepage Journal

    It's one of those summaries.

    You know "update on [OSS product]"

    Why would we, the general populace of readers, want a very short summary of what this OSS product does, when we can have unclear references to the changelog?
    Why would we want a link to the homepage with more information, when we can have 2 links that also are essentially changelogs, and one direct download?

    If it's not the Linux Kernel, Firefox, or Chrome, please stop assuming everyone knows what it is.

    • by Anonymous Coward

      But it's LLVM 3.5 along with Clang 3.5! And it unifies the Apple and AArch64 backends along with C++1y/C++1z additions! It's self-explanatory, surely?

    • by jandrese ( 485 )
      Man, if only there were some way to look up information you don't know. Some service you could type a clearly easy to search for string like "llvm" into to get as much information on the topic as you need...

      Are you reading Slashdot in print form in some place with no internet access? Do you have to call your secretary so she can type out the comments on a punched card to feed into the internetotron?
      • Re: (Score:3, Insightful)

        by i kan reed ( 749298 )

        How about, fuck you, you could just look up LLVM anytime you wanted news about it. Why come to slashdot for that? See how stupid that "resources exist" argument is?

        Decent journalism isn't hard, and I don't feel that basic fucking context is too much to ask of a summary.

        • It is not out of the question for Slashdot submissions to expect their target audience to know about LLVM and Clang. If you didn't then you weren't the target audience.

          It would be like me having to write "Obama (the current US president)..." in a Democratic Party Newsletter or "Alabama (a US State)..." on an American news site.

          Do we have to explain what a "Tesla Model S" or a "Ford Escort" is to the reader? No, because they been around long enough that it can be expected that most of the audience will kn

          • Right... let's take that a bit of a different direction, and instead of the US president, talk about, say, the minority whip and see how well your analogy holds up.

            • by Threni ( 635302 )

              It would be a good analogy if you were talking about, say, a site which was targeted at - and largely read by - people interested in political issues.

              It's perfectly reasonably to understand that the majority of Slashdot users either know what Clang/LLVM is, or are willing and capable of looking them up. Clearly, if you've not idea what Clang is, then you're going to skate on over the headline to the next stor, just like I did when I saw the headline about giving cyborgs rights.

            • His analogy holds up pretty much perfectly.

              I would expect someone who reads the Democratic Party Newsletter to know who the majority whip is, but not really anyone else. Pretty much just like anyone on slashdot who isn't new should have hard of llvm and clang. Its a fairly common talking point for slashdot stories and comments.

              If you don't know what LLVM and clang are, slashdot really isn't someplace you should visit frequently unless you willing to learn what they are.

              • Sorry, but democratic-party-news-letter::slashdot isn't an analogy that holds up. More like WashingtonPost::slashdot.

                (And democratic party newsletters would totally mention the name of the whip, you're totally crazy)

          • > Maybe you'll find CNet, USA Today, or Highlights for Children more acceptable.

            And you're expecting him to know who Goofus and Gallant are?!

    • by Anonymous Coward
      I miss the good old days when it was just geeks that would understand the story posting on Slashdot. Now we have to put up with posers.
    • by Anonymous Coward

      Slashdot has everything a nerd could want

      Apart from two things: Editors and Journalism.

  • Nerds are not interested in champagne & handbags. Get ye to idle!

  • by Guy Harris ( 3803 ) <guy@alum.mit.edu> on Friday September 05, 2014 @04:18PM (#47837817)

    The article pointed to the very very very very very incomplete release notes for stuff after 3.5.

    You wanted to link to the 3.5 release notes [llvm.org].

    • by jandrese ( 485 )
      Where are the CLang release notes? They are not where I expect them to be [llvm.org]. I was really hoping they've implemented C11's _atomic keyword, but I have my doubts.
      • by fnj ( 64210 )

        Yeah, somebody please PLEASE track them down. Frankly LLVM itself is boring (don't hit me). The clang part is where the interesting stuff is. Why in hell doesn't somebody fix that miserable horror of a website?

        Look at this [llvm.org] fucking page. As I write this the title says "Clang 3.5 (In-Progress) Release Notes - Clang 3.6 documentation". The top heading says "Clang 3.6 documentation". The level 2 subheading says "Clang 3.5 (In-Progress) Release Notes". The level 3 heading says "Clang 3.5 (In-Progress) Release No

        • by fnj ( 64210 )

          OK, I think I found it [llvm.org] - by downloading the clang source, opening the release notes file in the archive, and doing a google search for the exact phrase.

          Hope this helps. It's actually great quality work, if they only made it possible to FIND it on the website.

  • by Anonymous Coward

    I've been using LLVM and Clang a lot lately. They're an exceptionally good compiler system. The more I use it, the more I ask myself, Is there even any point continuing the development of GCC?

    All software projects come to an end eventually. Something better comes along, and those who can't compete are better off giving up. I think that GCC has entered that phase, now that we have LLVM and Clang available to us.

    LLVM and Clang have a better code base, a freer license, better runtime performance, better corpor

    • by Anonymous Coward on Friday September 05, 2014 @05:40PM (#47838317)

      rarely-used languages and platforms

      Rarely-used platforms? Tell that to all the people developing for various embedded platforms like AVR which LLVM doesn't support. Those aren't rarely used.

    • Actually I still use gcc for gfortran - I can't personally afford to use the commercial license, and I have code I want to maintain and develop in Fortran. But on Windows I develop C++ in either MSVC, due chiefly to the fact I like its debugger better than any other I've worked with, or in Clang, and on Linux I develop C++ in Clang. I'm glad gcc is there but my default these days is certainly Clang.

    • by Anonymous Coward on Friday September 05, 2014 @05:48PM (#47838353)

      Better corporate support? I might have missed it, but e.g. Intel, Google, ARM, AMD, etc. are still also making significant contributions to GCC.

      Better runtime performance? Have you even read the Phoronix article?

      People using Ada and Fortran using the better compilers out there... Eh... GNU Ada is *the* Ada compiler standard, and GNU Fortran is widely used even in high-performance computing because the commercial compilers aren't really better at all (and generally more buggy).

      Go do your home work.

      • Re: (Score:2, Interesting)

        "GNU Fortran is widely used even in high-performance computing because the commercial compilers aren't really better at all (and generally more buggy)."

        While I've certainly encountered (and notified Intel of) bugs in ifort, and more than I'd expect in something that cost the university a pretty parcel of money, I wouldn't even begin to pretend that gfortran is as good for high-performance computing as ifort. Unless you're triggering an ifort bug, and I haven't hit a genuinely serious one since a weird memor

      • Better runtime performance? Have you even read the Phoronix article?

        So there is just one, right? One lone article on Phoronix?

        • Actually, it seems that Phoronix tests are the best available around - at least a quick search didn't reveal any further recent tests. Besides, that's what TFA links to.

          If you wish to imply that Phoronix tests are somehow skewed in favour of GCC, why don't you provide a link to tests claiming otherwise?
          • No, my point is that there are quite a lot of articles re: GCC vs. Clang on Phoronix, and that the comparisons are quite a bit more thorough and the results more varied than the parent hinted at with his/her implied claim that ‘the’ Phoronix article proves how GCC runtime performance is better. I read another article (at http://www.phoronix.com/scan.p... [phoronix.com]), and though it’s half a year old, it still shows that the compilers can be neck to neck in one area, and that they beat one another in v
    • by Eravnrekaree ( 467752 ) on Friday September 05, 2014 @06:22PM (#47838543)

      GCC's support for Fortran and Ada make it valuable, the point is the need for an open source compiler so when your requirement is open source a commercial compiler wont do. Many assiduously avoid closed source software and want to be able to have the facility for ada and fortran. Many "infrequently used" platforms are more important than you think, such as the system Z platform from IBM.

    • by tlhIngan ( 30335 )

      The more I use it, the more I ask myself, Is there even any point continuing the development of GCC?

      Well, the "advantage" of GCC is it's GPL. To a large number of FOSS people, the GPL is a far better license than BSD, so it doesn't matter if LLVM/CLang is better, superior or whatever, GCC is GPL and that is all that matters.

      Also, there's a lot of GCC-isms out there in the code, many of which are not supported by LLVM/Clang or other compilers and they often do strange things so porting them to use another co

    • I'm using GNAT Ada with GCC, as practically all other Ada users. GNAT is the only Ada version that implements the latest language features of Ada 2012.

      Adacore alone is reason enough to continue developing GCC. The commercial version of GNAT uses GCC and is used in production systems like airplanes you fly with.

  • Lies (Score:3, Funny)

    by Tailhook ( 98486 ) on Friday September 05, 2014 @04:25PM (#47837843)

    Apple didn't contribute any work to LLVM/clang because LLVM/clang are licensed with U of I's BSD-ish and, as we all know, corporate capitalist pig-dogs will not contribute if they're not forced to by license requirements.

    Can't believe anything you read on Slashdot these days.

    • Maybe if you had read the release notes you wouldn't have posted such a retarded comment. Oh, and large chunks of the llvm/clang team work at Apple.

      "During the 3.5 release cycle, Apple released the source used to generate 64-bit ARM programs on iOS platforms. This took the form of a separate backend that had been developed in parallel to, and largely isolation from, the existing code.

      We decided that maintaining the two backends indefinitely was not an option, since their features almost entirely overlapped.

      • by caseih ( 160668 )

        Oh dear. I guess your browser doesn't render the humor or sarcasm tags properly. The parent comment was intended to be snarky humor poking fun at those of us who think the gpl is a good idea. Whether or not it was actually funny is debatable of course.

        • Oh dear. I guess your browser doesn't render the humor or sarcasm tags properly. The parent comment was intended to be snarky humor poking fun at those of us who think the gpl is a good idea. Whether or not it was actually funny is debatable of course.

          With a user number about the same as mine, you have spent enough time on the internet to realize that sarcasm generally doesn't communicate well through plain text. No matter how outlandish and stupid you think your sarcasm sounds, I guarantee you that there is a significantly non-zero number of people on the same forum who are actually stupid enough to post in earnest what you posted sarcastically. So you shouldn't be surprised when people take your sarcasm as stupidity in earnest.

    • by Anonymous Coward

      But Apple did use the hard work of open source developers to subsidize a closed platform of user and developer hostile products. When companies want to exploit their customers to the fullest they should not be able to benefit from the efforts of open source developers, they should have to hire developers and write their own code from scratch. All BSD licensing accomplishes is the depression of wages paid to developers. GPL licensing makes up for the depression of wages by creating a better world.

  • by IllForgetMyNickSoonA ( 748496 ) on Saturday September 06, 2014 @04:45AM (#47840053)
    What's the LLVM / clang fuss about anyway? I keep hearing about LLVM for years already, it's presented by its' supporters (of which many have never actually even tried it out, I bet!) as "The Solution To All (alleged) GCC Problems", but it somehow fails to replace the GCC as an omnipresent compilation system.

    Until there is not a single Linux distribuition out there compiled with LLVM / clang, and there still is none, it will just not cut it.

    Besides, as the Phoronix article shows, it's also not on-par performance-wise.

    I'd love to move to a compiler with better / more understandable errors and warnings, especially for C++, and which compiles faster - but until the code does not execute at the same speed (and it seems it mostly lags behind GCC), and until it is not integrated into the system adequately (read: LLVM-based distribution), I do not see the point in switching.
    • Instead of only talking out of my a$$, I just compiled a small QT project of mine (8333 LOC, spread over 60 files (including auto generated moc files), lines counted with "wc -l"), with gcc 4.8.2 and with clang 3.5 (these are per default available on Ubuntu 14.04), and it seems that the compilation times are nearly identical:

      CLANG:

      real 0m26.100s
      user 0m24.815s
      sys 0m1.208s


      GCC:

      real 0m27.936s
      user 0m26.715s
      sys 0m1.755s


      All files (including compilers, libraries and includes
      • With compilers, what counts is the speed of compiled code rather than compilation speed, and here clang loses by quite a bit.

        Compilation speed really matters only in rapid compile-debug cycles, but there clang, despite winning on compile speed, is hindered by producing worse debug info.

        • I agree (except that I value compile time higher than you do, it seems, but clang doesn't seem to deliver THAT much in this area either), and that's why I can't do differently but wonder what the fuss is all about.
        • With compilers, what counts is the speed of compiled code rather than compilation speed, and here clang loses by quite a bit.

          Says who? For the first statement, I haven't seen any code in the last few years where the difference between compiler optimisations would have made any difference. I haven't actually seen any code that needed any cleverness. I have seen code that needed stupidity removed, but nothing else.

          For the second statement, there is a benchmark that shows gcc to be better, and goes what, the gcc developers try their best to optimise for it, while everyone else ignores it. The results are predictable.

    • Replying (again) to my own post, just found out that llvm supports only DWARF3 debugging imformation, while gcc is on a DWARF4. One more reason to wonder about where the llvm buzz comes from.
    • by Anonymous Coward

      It's getting common to develop C++ with Clang, then distribute with GCC.
      Though it's not huge in Linux camps, BSD is using Clang.

      LLVMLinux getting closer (similar performance, and very few patches needed, soon none):
      http://www.phoronix.com/scan.php?page=news_item&px=MTcxNDA
      and it compiles Debian's repos quite well too, with most problems being edge cases and standard differences.
      Distributions need this groundwork first.

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