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From:   =?UTF-8?B?RsSBbmctcnXDrCBTw7JuZw==?= <maskray@google.com>
Date:   Fri, 13 Nov 2020 09:28:03 -0800
Message-ID: <CAFP8O3LpSmxVnjHfQAN455k1ZRg3PbgZYhWr030evCq1T10k=Q@mail.gmail.com>
Subject: Re: Error: invalid switch -me200
To:     kernel test robot <lkp@intel.com>
Cc:     kbuild-all@lists.01.org,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>
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On Thu, Nov 12, 2020 at 7:22 PM kernel test robot <lkp@intel.com> wrote:
>
> Hi Fangrui,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba
> commit: ca9b31f6bb9c6aa9b4e5f0792f39a97bbffb8c51 Makefile: Fix GCC_TOOLCHAIN_DIR prefix for Clang cross compilation
> date:   4 months ago
> config: powerpc-randconfig-r031-20201113 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9e0c35655b6e8186baef8840b26ba4090503b554)
> 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
>         # install powerpc cross compiling tool for clang build
>         # apt-get install binutils-powerpc-linux-gnu
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ca9b31f6bb9c6aa9b4e5f0792f39a97bbffb8c51
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout ca9b31f6bb9c6aa9b4e5f0792f39a97bbffb8c51
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>    Assembler messages:
> >> Error: invalid switch -me200
> >> Error: unrecognized option -me200
>    clang-12: error: assembler command failed with exit code 1 (use -v to see invocation)
>    make[2]: *** [scripts/Makefile.build:281: scripts/mod/empty.o] Error 1
>    make[2]: Target '__build' not remade because of errors.
>    make[1]: *** [Makefile:1174: prepare0] Error 2
>    make[1]: Target 'prepare' not remade because of errors.
>    make: *** [Makefile:185: __sub-make] Error 2
>    make: Target 'prepare' not remade because of errors.
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

This can be ignored. The LLVM integrated assembler does not recognize
-me200 (-Wa,-me200 in arch/powerpc/Makefile). I guess the GNU as -m
option is similar to .arch or .machine and controls what instructions
are recognized. The integrated assembler tends to support all
instructions (conditional supporting some instructions has some
challenges; in the end I have patched parsing but ignoring `.arch` for
x86-64 and ignoring `.machine ppc64` for ppc64)

(In addition, e200 is a 32-bit Power ISA microprocessor. 32-bit
support may get less attention in LLVM.)