[FFmpeg-trac] #9399(avcodec:new): ld: warning: could not create compact unwind

[FFmpeg]

#9399: ld: warning: could not create compact unwind
-------------------------------------+-------------------------------------
             Reporter:  Daniel       |                     Type:  defect
  Schürmann                          |
               Status:  new          |                 Priority:  normal
            Component:  avcodec      |                  Version:
             Keywords:  dwarf stack  |  unspecified
  size compact unwind                |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 When trying to link ffmpeg statically with Mixxx on macOS, the Apple
 linker is complaining:
 {{{
 2021-08-18T22:06:41.3473950Z ld: warning: could not create compact unwind
 for _ff_cfhd_init_vlcs: stack subq instruction is too different from dwarf
 stack size
 2021-08-18T22:06:41.3475230Z ld: warning: could not create compact unwind
 for _ff_rl_init_vlc: stack subq instruction is too different from dwarf
 stack size
 }}}

 This happens with gcc and clang 12.0.0.12000032

 The issue was original reported here:
 https://github.com/microsoft/vcpkg/issues/19699

 Only these two functions are reported. When I disable cfhd encoder and
 decoder, one warning disappears.

 I can also specify {{{ LDFLAGS="-Wl,-no_compact_unwind" }}} to make remove
 this warning, but that will affect all functions.

 Both functions locate big arrays on the stack, my guess it that these
 arrays are too big for compact unwind.

 What is the best option to lower the used stack?

 Do you know what is the limit for unwinding, the dwarf stack size?

 Thank you.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9399>
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