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Subject: Re: [gustavoars-linux:for-next/clang-fallthrough 1/1] warning:
 fallthrough annotation in unreachable code/
To:     Nathan Chancellor <nathan@kernel.org>,
        kernel test robot <lkp@intel.com>
Cc:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        clang-built-linux@googlegroups.com, kbuild-all@lists.01.org,
        LKML <linux-kernel@vger.kernel.org>
References: <202108051403.tBfqfI49-lkp@intel.com>
 <YQw2P8esj8PMNRQn@Ryzen-9-3900X.localdomain>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Message-ID: <19cb5505-9f81-3fc2-394e-365a5b230cba@embeddedor.com>
Date:   Thu, 5 Aug 2021 16:52:23 -0500
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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 <lkp@intel.com>
>>
>> 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