1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

Building Linux With LLVM/Clang Excites The Embedded World

Compiler

Published on 09 March 2013 04:25 PM EST
Written by Michael Larabel in Compiler
39 Comments

Building the Linux kernel with LLVM/Clang rather than GCC continues to be a big focus within the embedded Linux community.

Qualcomm among other ARM vendors have been interested in building the Linux kernel with LLVM/Clang. It's possible to build kernels with this alternative open-source C/C++ compiler, but out-of-tree patches are currently required to the Linux kernel and not everything works smoothly. There's a long TODO list until everything is polished and LLVM/Clang becomes a first-class compiler for the Linux kernel, but the effort was formalized last year with the LLVMLinux project that is hosted by the Linux Foundation.

Among the reasons people continue to be interested in using Clang over GCC is the cleaner and easier to work with code-base of the compiler, compilation times are often faster while using less RAM, there's an assortment of static analysis tools and other useful benefits over GCC, and the compiler is under a BSD-style license.

Developers also are pushing the Linux kernel -- and other key software packages -- through Clang since it leads to more portable code by pushing it through more compilers. Among the challenges that the LLVM Linux project has faced is GCC defaulting to using GNU89 of the C language while Clang defaults to GNU99, the kernel using undocumented GCC behavior, unsupported GCC flags, and Kconfig being GCC-specific.

The state of building the Linux kernel with Clang was talked about last month at the Linux Foundation's Embedded Linux Conference 2013. Embedded below is the video of the talk. For those curious about the state of not using GCC to build the Linux kernel, visit the LF project site.

The good news shared during the presentation is that LLVM/Clang 3.3 will likely work "mostly out-of-the-box" for the Linux kernel, albeit patches are still required on the kernel side. (Right now about four patches are require to upstream LLVM/Clang for x86_64 Linux support.)

Slides of the ELC 2013 presentation can be found on Google Docs.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Articles & Reviews
  1. Intel Broadwell: GCC 4.9 vs. LLVM Clang 3.5 Compiler Benchmarks
  2. Ubuntu vs. Fedora Linux On Lenovo's X1 Carbon With Core i7 Broadwell
  3. Ubuntu 15.04 Is The Easy Path To Better Performance On Intel Broadwell
  4. NVIDIA's Latest Maxwell Line-Up Against AMD With Catalyst On Linux
  5. Preliminary Tests Of Intel Sandy Bridge & Ivy Bridge vs. Broadwell
  6. AMD FX-8320E Performance On Linux
Latest Linux News
  1. I Switched (Back) Over To Fedora As My Main OS & It's Going Great!
  2. Windows 10, PS4, C4 & Systemd News Kicked Off 2015
  3. Calamares 1.0 Distribution-Independent Installer Framework Released
  4. Librem 15 Linux Laptop Set To Close At Around $400k USD
  5. Virtual GEM To Increase Mesa's Software Rasterizer Performance
  6. Open Lunchbox: Yet Another Open-Source Laptop Attempt
  7. Wayland/Weston 1.7 Release Candidate
  8. Bugzilla 5.0 Is Coming Soon With New Features
  9. Linux Benchmarking... Even Faster & A Very Interesting February
  10. Does VirtualBox VM Have Much A Future Left?
Most Viewed News This Week
  1. PlayStation 4 System Compiler Support Landing In LLVM
  2. Does VirtualBox VM Have Much A Future Left?
  3. Linux "GHOST" Vulnerability Hits Glibc Systems
  4. LibreOffice 4.4 Is Coming Soon With New Features
  5. LLVM Adds Options To Do Fuzz Testing
  6. LibreOffice 4.4 Released With Better OOXML Support, UI Improvements
  7. Inkscape 0.91 Goes Through C++ Code Conversion, New Cairo Rendering, OpenMP Filters
  8. Broadwell Linux Ultrabook Running MUCH Cooler Than Haswell