[FFmpeg-trac] #11302(avcodec:new): RISCV: Properly set relocate parameter of const macro in libavcodec/riscv/h264dsp_rvv.S

[FFmpeg]

#11302: RISCV: Properly set relocate parameter of const macro in
libavcodec/riscv/h264dsp_rvv.S
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             Reporter:  kxxt        |                    Owner:  (none)
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:              |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Description changed by kxxt:

Old description:

> Summary of the bug:
>
> I am building chromium for riscv64 which builds ffmpeg using its own
> build system. I encountered the following error:
>
> ld.lld: error: relocation R_RISCV_64 cannot be used against symbol
> 'ff_h264_weight_pixels16_8_rvv'; recompile with -fPIC
> >>> defined in
> obj/third_party/ffmpeg/libffmpeg_internal.a(ffmpeg_internal/h264dsp_rvv.o)
> >>> referenced by
> ffmpeg_internal/h264dsp_rvv.o:(ff_h264_weight_funcs_8_rvv) in archive
> obj/third_party/ffmpeg/libffmpeg_internal.a
>
> It is caused by
> https://github.com/FFmpeg/FFmpeg/blob/7332b1700e3b257dd80341f40305cf0bf4582fcf/libavcodec/riscv/h264dsp_rvv.S#L163-L176
> which uses the const macro from libavutil/riscv/asm.S without enabling
> relocatable parameter.
>
> Could we enable the relocatable parameter unconditionally here? Or would
> it break the build in position dependent code mode?

New description:

 Summary of the bug:

 I am building chromium for riscv64 which builds ffmpeg using its own build
 system. I encountered the following error when linking
 v8_context_snapshot_generator:

 ld.lld: error: relocation R_RISCV_64 cannot be used against symbol
 'ff_h264_weight_pixels16_8_rvv'; recompile with -fPIC
 >>> defined in
 obj/third_party/ffmpeg/libffmpeg_internal.a(ffmpeg_internal/h264dsp_rvv.o)
 >>> referenced by
 ffmpeg_internal/h264dsp_rvv.o:(ff_h264_weight_funcs_8_rvv) in archive
 obj/third_party/ffmpeg/libffmpeg_internal.a

 It is caused by
 https://github.com/FFmpeg/FFmpeg/blob/7332b1700e3b257dd80341f40305cf0bf4582fcf/libavcodec/riscv/h264dsp_rvv.S#L163-L176
 which uses the const macro from libavutil/riscv/asm.S without enabling
 relocatable parameter.

 Could we enable the relocatable parameter unconditionally here? Or would
 it break the build in position dependent code mode?

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Ticket URL: <https://trac.ffmpeg.org/ticket/11302#comment:1>
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