Re: clang-12: i386: Unsupported relocation type: R_386_PLT32 (4)

[Sedat Dilek]

On Mon, Feb 22, 2021 at 5:08 PM Naresh Kamboju
<naresh.kamboju@xxxxxxxxxx> wrote:
>
> While building i386 configs on stable-rc 5.10, stable-rc 5.11 branch
> and mainline
> with clang-12 these following warnings and errors were noticed.
>

Hi Naresh,

Please see commit bb73d07148c405c293e576b40af37737faf23a6a
("x86/build: Treat R_386_PLT32 relocation as R_386_PC32").
Recently accepted into Linus Git tree.

[1] says:

Further info for the more interested:

  https://github.com/ClangBuiltLinux/linux/issues/1210
  https://sourceware.org/bugzilla/show_bug.cgi?id=27169
  https://github.com/llvm/llvm-project/commit/a084c0388e2a59b9556f2de0083333232da3f1d6

Hope that helps.

- Sedat -

[1] https://git.kernel.org/linus/bb73d07148c405c293e576b40af37737faf23a6a

> make --silent --keep-going --jobs=8
> O=/home/tuxbuild/.cache/tuxmake/builds/1/tmp ARCH=i386
> CROSS_COMPILE=i686-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache
> clang'
>
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:2586:9: warning: shift
> count >= width of type [-Wshift-count-overflow]
>
>         return hweight64(VDBOX_MASK(&i915->gt));
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/asm-generic/bitops/const_hweight.h:29:49: note: expanded from
> macro 'hweight64'
> #define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) :
> __arch_hweight64(w))
>                                                 ^~~~~~~~~~~~~~~~~~~~
> include/asm-generic/bitops/const_hweight.h:21:76: note: expanded from
> macro '__const_hweight64'
> #define __const_hweight64(w) (__const_hweight32(w) +
> __const_hweight32((w) >> 32))
>                                                                            ^  ~~
> include/asm-generic/bitops/const_hweight.h:20:49: note: expanded from
> macro '__const_hweight32'
> #define __const_hweight32(w) (__const_hweight16(w) +
> __const_hweight16((w) >> 16))
>                                                 ^
> include/asm-generic/bitops/const_hweight.h:19:48: note: expanded from
> macro '__const_hweight16'
> #define __const_hweight16(w) (__const_hweight8(w)  +
> __const_hweight8((w)  >> 8 ))
>                                                ^
> include/asm-generic/bitops/const_hweight.h:10:9: note: expanded from
> macro '__const_hweight8'
>          ((!!((w) & (1ULL << 0))) +     \
>                ^
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:2586:9: warning: shift
> count >= width of type [-Wshift-count-overflow]
>         return hweight64(VDBOX_MASK(&i915->gt));
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> <trim>
>
> 32 warnings generated.
> Unsupported relocation type: R_386_PLT32 (4)
> make[3]: *** [arch/x86/boot/compressed/Makefile:116:
> arch/x86/boot/compressed/vmlinux.relocs] Error 1
> make[3]: *** Deleting file 'arch/x86/boot/compressed/vmlinux.relocs'
> make[3]: Target 'arch/x86/boot/compressed/vmlinux' not remade because of errors.
>
> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
>
> Steps to reproduce:
> ---------------------------
> # TuxMake is a command line tool and Python library that provides
> # portable and repeatable Linux kernel builds across a variety of
> # architectures, toolchains, kernel configurations, and make targets.
> #
> # TuxMake supports the concept of runtimes.
> # See https://docs.tuxmake.org/runtimes/, for that to work it requires
> # that you install podman or docker on your system.
> #
> # To install tuxmake on your system globally:
> # sudo pip3 install -U tuxmake
> #
> # See https://docs.tuxmake.org/ for complete documentation.
>
> tuxmake --runtime podman --target-arch i386 --toolchain clang-12
> --kconfig defconfig  --kconfig-add
> https://builds.tuxbuild.com/1opxSKxZuRowPsiOsSJ0IoUOXOt/config
>
> --
> Linaro LKFT
> https://lkft.linaro.org
>
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