7 ms·

I'm glad that VoidLinux isn't anymore the only distro in town that's switched to LibreSSL. And with Docker defaulting to Alpine, more OpenSSL/LibreSSL compatibi

by cm3 10y ago

I'm glad that VoidLinux isn't anymore the only distro in town that's switched to LibreSSL. And with Docker defaulting to Alpine, more OpenSSL/LibreSSL compatibility fixes will trickle into upstream projects. This is good news. EDIT: Next, I predict a linux distro will, after having switched to musl, also support llvm/compiler-rt/libunwind/libc++ as base toolchain instead of gcc/libgcc/libstdc++

rvense 10y ago
Can Clang/LLVM compile Linux itself?
- qznc 10y ago
  No. https://llvm.org/bugs/show_bug.cgi?id=4068 https://llvm.org/bugs/show_bug.cgi?id=4068 https://www.phoronix.com/scan.php?page=news_item&px=Clang-The-Kernel-2016 https://www.phoronix.com/scan.php?page=news_item&px=Clang-Th...
- cm3 10y ago
  A not-yet-fully-upstreamed branch maintained by the linux foundation can, yes. But just like FreeBSD has to make an exception to build certain packages with gcc, the kernel can be exclusively built with gcc for the time being. If you're not using musl libc, I guess glibc might also require gcc but that's an unsurprising coupling, likely due to gcc C extensions in use. The important points are that such a distro will quickly improve the situation of clang and libc++ compatibility across the board and exercise the alternative toolchain a lot more. In fact, there isn't much incompatible code out there, and it's been fixed mostly due to efforts of Debian, FreeBSD and of course Apple and Bitrig and Gentoo. FreeBSD is the leading force behind making lld a viable alternative to binutils ld and so far ThinLTO (which works with binutils, to be clear) is exclusive to llvm, so there's that. https://aur.archlinux.org/packages/llvmlinux-git/ https://aur.archlinux.org/packages/llvmlinux-git/ http://llvm.linuxfoundation.org/index.php/Main_Page http://llvm.linuxfoundation.org/index.php/Main_Page
  - bogomipz 10y ago
    Can you remind me why LLVM/CLANG can't compile the linux kernel? Is it dependance on GCC extensions?
    - justincormack 10y ago
      I think those are mostly fixed for C code, but assembly still has issues. Otherwise dependence on exact gcc behaviour is an issue.
      - bogomipz 10y ago
        thanks
    - valarauca1 10y ago
      TL;DR Yeah GCC specific compiler compiler extensions. GCC has some platform specific symbols that are really just functions wrapping assembly. Most of this is related to crypto and AESNI (built in x86 AES operations). This breaks some crypto, which breaks some wifi/file system stuff. XEN driver uses a GCC specific ASM macro for counting NUMA Nodes and CPU cores. Dynamic compiling within the kernel for say BSD Packet Filtering JIT requires LLVM Compiler-RT have a custom wrapper. Also some libgcc specific header information.
vbernat 10y ago
It is quite unlikely that generic Linux distributions will switch to musl as it lacks support of locales and NSS.
- cm3 10y ago
  Right, that's why I wrote "_a_ linux distro", not "some linux distros". I'm sorry for not making that clearer.
justincormack 10y ago
NetBSD has had two installs, one with the gcc chain and one with the llvm chain for some years now. unwind compatibility was a problem but is getting better I think. For the base distro it makes less difference perhaps, although more C++ code is coming in.
- bogomipz 10y ago
  What is "unwind compatibility"?
  - justincormack 10y ago
    The clang and gcc unwind libraries have slightly different interfaces.
    - bogomipz 10y ago
      thanks
zeveb 10y ago
> EDIT: Next, I predict a linux distro will, after having switched to musl, also support llvm/compiler-rt/libunwind/libc++ as base toolchain instead of gcc/libgcc/libstdc++ You're probably right, but I hate that the work free software developers contribute to LLVM & clang will end up being taken proprietary by the likes of Apple. With GCC one knows that the users of one's code will always have the ability to run, read, modify & share that code, rather than having their rights stripped away.
- yellowapple 10y ago
  On the flip side, code from permissively-licensed projects (like LLVM/clang) can be incorporated into free software with GPL-incompatible licenses. I personally consider that gain to be more than worth the risk of proprietary forks. Also, the licenses of neither GCC nor LLVM apply to programs compiled by either project. I don't think that's what you meant by the copyleft sentiment, but the wording of that bit is weird and it's worth clarifying just in case.
- mioelnir 10y ago
  Please note that no company has the right to strip your copyright or license away. But they may chose to extend your software without giving you access to the extension, if that is permitted by the license.
- Sanddancer 10y ago
  Yes, some people won't give back. However, a project like llvm/clang, most people do give back because sharing is cool, and also it makes their job easier because they don't have to repatch for every new version of the compiler. Sony's team developing the Playstation 4 wished at times they could use newer versions of llvm/clang for their software, but couldn't because their version had so many patches [1]. Because of this, after the PS4 was released, Sony developers sent a bunch of patches upstream, and work pretty closely with the rest of the developers. Some bits and pieces may not get merged upstream, but that's the same for any project, GPL or not. [1] http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain.pdf http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain....
- justincormack 10y ago
Thaxll 10y ago
It's not anytime soon that musl will replace libc.

by cm3 10y ago

rvense 10y ago

Can Clang/LLVM compile Linux itself?

qznc 10y ago
No. https://llvm.org/bugs/show_bug.cgi?id=4068 https://llvm.org/bugs/show_bug.cgi?id=4068 https://www.phoronix.com/scan.php?page=news_item&px=Clang-The-Kernel-2016 https://www.phoronix.com/scan.php?page=news_item&px=Clang-Th...
cm3 10y ago
A not-yet-fully-upstreamed branch maintained by the linux foundation can, yes. But just like FreeBSD has to make an exception to build certain packages with gcc, the kernel can be exclusively built with gcc for the time being. If you're not using musl libc, I guess glibc might also require gcc but that's an unsurprising coupling, likely due to gcc C extensions in use. The important points are that such a distro will quickly improve the situation of clang and libc++ compatibility across the board and exercise the alternative toolchain a lot more. In fact, there isn't much incompatible code out there, and it's been fixed mostly due to efforts of Debian, FreeBSD and of course Apple and Bitrig and Gentoo. FreeBSD is the leading force behind making lld a viable alternative to binutils ld and so far ThinLTO (which works with binutils, to be clear) is exclusive to llvm, so there's that. https://aur.archlinux.org/packages/llvmlinux-git/ https://aur.archlinux.org/packages/llvmlinux-git/ http://llvm.linuxfoundation.org/index.php/Main_Page http://llvm.linuxfoundation.org/index.php/Main_Page
- bogomipz 10y ago
  Can you remind me why LLVM/CLANG can't compile the linux kernel? Is it dependance on GCC extensions?
  - justincormack 10y ago
    I think those are mostly fixed for C code, but assembly still has issues. Otherwise dependence on exact gcc behaviour is an issue.
    - bogomipz 10y ago
      thanks
  - valarauca1 10y ago
    TL;DR Yeah GCC specific compiler compiler extensions. GCC has some platform specific symbols that are really just functions wrapping assembly. Most of this is related to crypto and AESNI (built in x86 AES operations). This breaks some crypto, which breaks some wifi/file system stuff. XEN driver uses a GCC specific ASM macro for counting NUMA Nodes and CPU cores. Dynamic compiling within the kernel for say BSD Packet Filtering JIT requires LLVM Compiler-RT have a custom wrapper. Also some libgcc specific header information.

vbernat 10y ago

It is quite unlikely that generic Linux distributions will switch to musl as it lacks support of locales and NSS.

cm3 10y ago
Right, that's why I wrote "_a_ linux distro", not "some linux distros". I'm sorry for not making that clearer.

justincormack 10y ago

NetBSD has had two installs, one with the gcc chain and one with the llvm chain for some years now. unwind compatibility was a problem but is getting better I think. For the base distro it makes less difference perhaps, although more C++ code is coming in.

bogomipz 10y ago
What is "unwind compatibility"?
- justincormack 10y ago
  The clang and gcc unwind libraries have slightly different interfaces.
  - bogomipz 10y ago
    thanks

zeveb 10y ago

> EDIT: Next, I predict a linux distro will, after having switched to musl, also support llvm/compiler-rt/libunwind/libc++ as base toolchain instead of gcc/libgcc/libstdc++ You're probably right, but I hate that the work free software developers contribute to LLVM & clang will end up being taken proprietary by the likes of Apple. With GCC one knows that the users of one's code will always have the ability to run, read, modify & share that code, rather than having their rights stripped away.

yellowapple 10y ago
On the flip side, code from permissively-licensed projects (like LLVM/clang) can be incorporated into free software with GPL-incompatible licenses. I personally consider that gain to be more than worth the risk of proprietary forks. Also, the licenses of neither GCC nor LLVM apply to programs compiled by either project. I don't think that's what you meant by the copyleft sentiment, but the wording of that bit is weird and it's worth clarifying just in case.
mioelnir 10y ago
Please note that no company has the right to strip your copyright or license away. But they may chose to extend your software without giving you access to the extension, if that is permitted by the license.
Sanddancer 10y ago
Yes, some people won't give back. However, a project like llvm/clang, most people do give back because sharing is cool, and also it makes their job easier because they don't have to repatch for every new version of the compiler. Sony's team developing the Playstation 4 wished at times they could use newer versions of llvm/clang for their software, but couldn't because their version had so many patches [1]. Because of this, after the PS4 was released, Sony developers sent a bunch of patches upstream, and work pretty closely with the rest of the developers. Some bits and pieces may not get merged upstream, but that's the same for any project, GPL or not. [1] http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain.pdf http://llvm.org/devmtg/2013-11/slides/Robinson-PS4Toolchain....
justincormack 10y ago

Thaxll 10y ago

It's not anytime soon that musl will replace libc.