On 09. 11. 18 16:36, Nathan Chancellor wrote:

On Fri, Nov 09, 2018 at 10:33:00AM +0100, Michal Simek wrote:

quoted

On 08. 11. 18 16:01, Nathan Chancellor wrote:

quoted

On Thu, Nov 08, 2018 at 07:45:42AM +0100, Michal Simek wrote:

quoted

On 07. 11. 18 18:48, Nick Desaulniers wrote:

quoted

On Wed, Nov 7, 2018 at 1:01 AM Michal Simek [off-list ref] wrote:

quoted

On 07. 11. 18 9:55, Nathan Chancellor wrote:

quoted

On Wed, Nov 07, 2018 at 09:46:12AM +0100, Michal Simek wrote:

quoted

On 01. 11. 18 1:57, Nathan Chancellor wrote:

quoted

Clang warns when one enumerated type is implicitly converted to another:

drivers/pinctrl/pinctrl-zynq.c:985:18: warning: implicit conversion from
enumeration type 'enum zynq_pin_config_param' to different enumeration
type 'enum pin_config_param' [-Wenum-conversion]
        {"io-standard", PIN_CONFIG_IOSTANDARD, zynq_iostd_lvcmos18},
        ~               ^~~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/pinctrl-zynq.c:990:16: warning: implicit conversion from
enumeration type 'enum zynq_pin_config_param' to different enumeration
type 'enum pin_config_param' [-Wenum-conversion]
        = { PCONFDUMP(PIN_CONFIG_IOSTANDARD, "IO-standard", NULL, true),
            ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/pinctrl/pinconf-generic.h:163:11: note: expanded from
macro 'PCONFDUMP'
        .param = a, .display = b, .format = c, .has_arg = d     \
                 ^
2 warnings generated.

This is interesting. I have never tried to use llvm for building the
kernel. Do you have any description how this can be done?

Depending on what version of Clang you have access to, it is usually just as
simple as running 'make ARCH=arm CC=clang CROSS_COMPILE=arm-linux-gnueabi-'.

Clang 7.0+ is recommended but 6.0 might work too.

TBH I would expect to download container and run this there to make sure
that I don't break anything else.

This is the first request we've had for a container in order to test a
patch.  If it comes up again from other folks, I think it makes sense
to create one.  Until then, its nice to have.  It's definitely
overkill for this patch.

I have played with it to see that error and here are some steps I did.

docker run --name test-clang -it --rm debian:latest bash
apt-get update
apt-get install gcc-arm-linux-gnueabi gcc-aarch64-linux-gnu clang git bc
build-essential bison flex make llvm vim libssl-dev sparse

git clone
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git --depth 1
cd linux

export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-

make defconfig

This should also have 'CC=clang' because compiler detection happens in
Kconfig now so compiler flags get properly set. Other than that, looks
good and I was able to build pinctrl-zynq.o without any issues with
those commands.

For arm32 I am still getting compilation issue (arm64 is fine)
Below are my steps and version I use. Do you know what could be the
problem?

Thanks,
Michal

root at 1e15921e6d15:~/linux# arm-linux-gnueabi-gcc --version
arm-linux-gnueabi-gcc (Debian 6.3.0-18) 6.3.0 20170516
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

root at 1e15921e6d15:~/linux# clang --version
clang version 3.8.1-24 (tags/RELEASE_381/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin


export ARCH=arm
export CROSS_COMPILE=arm-linux-gnuaebi-
make CC=clang defconfig
make CC=clang drivers/pinctrl/pinctrl-zynq.o

and I get
clang: error: unsupported argument '-W' to option 'Wa,'
scripts/Makefile.build:305: recipe for target 'scripts/mod/empty.o' failed
make[2]: *** [scripts/mod/empty.o] Error 1
scripts/Makefile.build:546: recipe for target 'scripts/mod' failed

Ah because Debian's regular Clang is ancient.

For testing, we use the builds from apt.llvm.org. Commands assuming
you're using the normal Debian image:

curl https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
echo "deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch main" | tee -a /etc/apt/sources.list
apt-get update -qq && apt-get install -y clang-8

Then use `CC=clang-8' instead of 'CC=clang' for all make invocations.

Still I see some issues. Log below.

Thanks,
Michal

root at 1e15921e6d15:~/linux# git reset --hard v4.20-rc2
HEAD is now at ccda4af0f4b9 Linux 4.20-rc2
root at 1e15921e6d15:~/linux#
root at 1e15921e6d15:~/linux#
root at 1e15921e6d15:~/linux# export ARCH=arm
root at 1e15921e6d15:~/linux# export CROSS_COMPILE=arm-linux-gnuaebi-
root at 1e15921e6d15:~/linux# export CC=clang-8
root at 1e15921e6d15:~/linux# make CC=clang-8 defconfig
  HOSTCC  scripts/kconfig/conf.o
  HOSTLD  scripts/kconfig/conf
*** Default configuration is based on 'multi_v7_defconfig'
#
# configuration written to .config
#
root at 1e15921e6d15:~/linux# make CC=clang-8
scripts/kconfig/conf  --syncconfig Kconfig
  SYSHDR  arch/arm/include/generated/uapi/asm/unistd-common.h
  SYSHDR  arch/arm/include/generated/uapi/asm/unistd-oabi.h
  SYSHDR  arch/arm/include/generated/uapi/asm/unistd-eabi.h
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  SYSNR   arch/arm/include/generated/asm/unistd-nr.h
  SYSTBL  arch/arm/include/generated/calls-oabi.S
  SYSTBL  arch/arm/include/generated/calls-eabi.S
  CC      kernel/bounds.s
clang: warning: argument unused during compilation: '-Wa,-W'
[-Wunused-command-line-argument]
clang: warning: argument unused during compilation: '-Wa,-march=armv7-a'
[-Wunused-command-line-argument]
  UPD     include/generated/bounds.h
  CC      arch/arm/kernel/asm-offsets.s
clang: warning: argument unused during compilation: '-Wa,-W'
[-Wunused-command-line-argument]
clang: warning: argument unused during compilation: '-Wa,-march=armv7-a'
[-Wunused-command-line-argument]
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
clang: warning: argument unused during compilation: '-Wa,-W'
[-Wunused-command-line-argument]
clang: warning: argument unused during compilation: '-Wa,-march=armv7-a'
[-Wunused-command-line-argument]
  CC      scripts/mod/empty.o
clang: error: unsupported argument '-W' to option 'Wa,'
scripts/Makefile.build:293: recipe for target 'scripts/mod/empty.o' failed
make[2]: *** [scripts/mod/empty.o] Error 1
scripts/Makefile.build:518: recipe for target 'scripts/mod' failed
make[1]: *** [scripts/mod] Error 2
Makefile:1075: recipe for target 'scripts' failed
make: *** [scripts] Error 2
root at 1e15921e6d15:~/linux# clang-8 --version
clang version 8.0.0-svn345496-1~exp1+0~20181029105533.852~1.gbpf10f36
(trunk)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
root at 1e15921e6d15:~/linux# arm-linux-gnueabi-gcc --version
arm-linux-gnueabi-gcc (Debian 6.3.0-18) 6.3.0 20170516
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.