I think this should have been fixed by https://github.com/google/autofdo/pull/65, pease re-open if otherwise. about autofdo

[pchome]

More info: on Gentoo this can be controlled by splitdebug and compressdebug FEATURES flags.
Which will do the following:

local objcopy_flags="--only-keep-debug"
${FEATURES_compressdebug} && objcopy_flags+=" --compress-debug-sections"
${OBJCOPY} ${objcopy_flags} "${x}" "${y}"
${OBJCOPY} --add-gnu-debuglink="${y}" "${x}"

where local y=${ED%/}/usr/lib/debug/${x:${#d_noslash}}.debug.

Generated example: mesa-progs-8.3.0.tar.gz

create_gcov -gcov_version=1 -use_lbr=false -binary=$(which glxgears)

I1107 15:12:50.406280 25129 perf_reader.cc:798] Number of events stored: 13181
I1107 15:12:50.438150 25129 perf_parser.cc:268] Parser processed: 96 MMAP/MMAP2 events, 2 COMM events, 0 FORK events, 1 EXIT events, 13079 SAMPLE events, 13079 of these were mapped
W1107 15:12:50.441745 25129 addr2line.cc:41] File '/usr/bin/glxgears' has no .debug_info section.  
W1107 15:12:50.441792 25129 addr2line.cc:41] File '/usr/bin/glxgears' has no .debug_ranges section.  
W1107 15:12:50.441807 25129 addr2line.cc:41] File '/usr/bin/glxgears' has no .debug_line section.  
W1107 15:12:50.441926 25129 module_grouper.cc:60] Cannot read compilation info from binary. Please use -frecord-compilation-info-in-elf when building the binary

[pchome]

debuglink.c.patch.txt -- a rough patch for elfutils debuglink.c test to print more debuglink info.

$ gcc debuglink.c -lelf -ldw -o debuglink
$ ./debuglink a.out $(which glxgears)  $(which glxinfo)
a.out: <no gnu_debuglink file>
Symbols in:
  module:     module1
  file:       a.out
  debugfile:  (null)
  symbols:    60
/usr/bin/glxgears: glxgears.debug, crc: 1dcf4a9
Symbols in:
  module:     module1
  file:       /usr/bin/glxgears
  debugfile:  /usr/lib/debug/usr/bin/glxgears.debug
  symbols:    179
/usr/bin/glxinfo: glxinfo.debug, crc: 6047213
Symbols in:
  module:     module1
  file:       /usr/bin/glxinfo
  debugfile:  /usr/lib/debug/usr/bin/glxinfo.debug
  symbols:    223

[justanerd]

This works still only with nostrip applied in gentoo.
Is there any easy fix to get create_gcov to find the debug file in /usr/lib/debug?