2021-08-05 08:19:28

by kernel test robot

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Subject: [gustavoars-linux:for-next/clang-fallthrough 1/1] warning: fallthrough annotation in unreachable code

tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git for-next/clang-fallthrough
head: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
commit: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00 [1/1] Revert "Revert "Makefile: Enable -Wimplicit-fallthrough for Clang""
config: hexagon-randconfig-r023-20210804 (attached as .config)
compiler: clang version 12.0.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
git remote add gustavoars-linux https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git
git fetch --no-tags gustavoars-linux for-next/clang-fallthrough
git checkout 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
2 warnings generated.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]


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2021-08-05 20:59:22

by Nathan Chancellor

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Subject: Re: [gustavoars-linux:for-next/clang-fallthrough 1/1] warning: fallthrough annotation in unreachable code/

On Thu, Aug 05, 2021 at 02:21:34PM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git for-next/clang-fallthrough
> head: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
> commit: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00 [1/1] Revert "Revert "Makefile: Enable -Wimplicit-fallthrough for Clang""
> config: hexagon-randconfig-r023-20210804 (attached as .config)
> compiler: clang version 12.0.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
> git remote add gustavoars-linux https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git
> git fetch --no-tags gustavoars-linux for-next/clang-fallthrough
> git checkout 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All warnings (new ones prefixed by >>):
>
> >> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
> >> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
> 2 warnings generated.

With a newer version of clang that shows proper line numbers:

sound/core/pcm_native.c:3812:3: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
fallthrough;
^
include/linux/compiler_attributes.h:211:41: note: expanded from macro 'fallthrough'
# define fallthrough __attribute__((__fallthrough__))
^
sound/core/pcm_native.c:3820:3: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
fallthrough;
^
include/linux/compiler_attributes.h:211:41: note: expanded from macro 'fallthrough'
# define fallthrough __attribute__((__fallthrough__))
^
2 warnings generated.

Which is already being tracked: https://github.com/ClangBuiltLinux/linux/issues/1429

Cheers,
Nathan

2021-08-06 01:23:07

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [gustavoars-linux:for-next/clang-fallthrough 1/1] warning: fallthrough annotation in unreachable code/



On 8/5/21 14:04, Nathan Chancellor wrote:
> On Thu, Aug 05, 2021 at 02:21:34PM +0800, kernel test robot wrote:
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git for-next/clang-fallthrough
>> head: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
>> commit: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00 [1/1] Revert "Revert "Makefile: Enable -Wimplicit-fallthrough for Clang""
>> config: hexagon-randconfig-r023-20210804 (attached as .config)
>> compiler: clang version 12.0.0
>> reproduce (this is a W=1 build):
>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
>> git remote add gustavoars-linux https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git
>> git fetch --no-tags gustavoars-linux for-next/clang-fallthrough
>> git checkout 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
>> # save the attached .config to linux build tree
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <[email protected]>
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
>>>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
>> 2 warnings generated.
>
> With a newer version of clang that shows proper line numbers:

Yep; I've been using mainline since you told us about commit

1b4800c26259 ("[clang][parser] Set source ranges for GNU-style attributes")

:)

> Which is already being tracked: https://github.com/ClangBuiltLinux/linux/issues/1429

Hopefully, this will be solved soon: https://bugs.llvm.org/show_bug.cgi?id=51094 (fingers crossed).

Thanks
--
Gustavo