[llvmlinux] Clang/LLVM for ARM rebase to 4.13

Sedat Dilek sedat.dilek at gmail.com
Mon Aug 7 09:35:28 UTC 2017

On Mon, Aug 7, 2017 at 9:17 AM, Stefan Agner <stefan at agner.ch> wrote:
> Hi,
> Fwiw, I rebased the Clang/LLVM patches required to build 32-bit ARM
> kernels to v4.13-rc4:
> http://git.agner.ch/gitweb/?p=linux.git;a=shortlog;h=refs/heads/armv7-master-clang-v4.13-rc4

Hi Stefan,

thanks for your feedback!

Do you happen to know (or have tested) the combination of Linux
v4.13-rc4 with x86_64 with your Git tree?

> I also run kernels built with Clang/LLVM 4.0.1 successfully (again,
> after I had issues with 4.0.0).

Did you try other versions of Clang (example: 3.9.x)?

Is this a self-compiled llvm-toolchain, prebuilt-toolchain (from
Linaro?) or offered by your $distro?

> The patch count dropped significantly since several Kbuild patches got
> merged recently.

Great to hear there is progress (to see patches I had in my own queue
are now in upstream [3]).

My personal opinion on llvmlinux (Clang): It is very helpful to make a
lot of warnings and errors visible.

Not happy why kbuild-patches which require a "cc-XXX" call are not
used by default (example see [1]).
Desired is a meachnism which handles this automagically, means check
if $compiler really supports $compiler-flag.

[4] is no more supported with recent Clang versions?
Embed in a cc-XXX-call instead?

Is your ext4-fix still necessary or fixed by [2] in upstream?

Looking at the list of [0] there are some more people doing good work
on getting stuff fixed with Clang.
What about the idea of co-working?

I have asked this a lot ob this mailing-list (I ask again):
What about an agreed development base using stable (released) versions
of llvm-toolchain, Linux-kernel (preferably LTS) release and
build-tools (binutils, llvm-$tools like assembler, linker, etc.).
It's a bit useless for me of not knowing how to reproduce ((re)build)
with your tree.
Example: You forgot to attach your kernel-config file, for me this is

Last but least, what is the plan to get some of your (for me obvious!)
patches upstream?
To keep tons of patches downstream is not very wise.
(If you have no "plan a" or "plan b" the alphabet has 24 more letters :-).)

Looking forward reading from you!

- Sedat -

[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=clang
[1] http://git.agner.ch/gitweb/?p=linux.git;a=commitdiff;h=4abb412be4937662495c027e9ee47089ad60395c
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2df2c3402fc81918a888e1ec711369f6014471f2
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4a1bec4605838fd7872ec41677585e241e256785
[4] http://git.agner.ch/gitweb/?p=linux.git;a=commitdiff;h=929b85c7afe1536c6d56b5b699c9fb264113ba38

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