[Bug gcov-profile/47618] Collecting multiple profiles and using all for PGO

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47618

--- Comment #24 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to qinzhao from comment #23)
> (In reply to Andrew Pinski from comment #7)
> > Created attachment 27869 [details]
> > Patch for adding merge-gcda
> > 
> > here is the patch which adds merge-gcda .  I don't add any testcases as it
> > is currently designed only for how Cavium's Simple-exec works in that each
> > core writes out its own gcda file.
> 
> I recently found this bug due to a similar problem. looks like that there
> are two parts of work for this problem:
> 
> 1. GCC's new feature to guarantee that all pre-merged files are saved with
> different names for different instances of the same process. 
> 2. a merge tool to merge all the gcda files afterwards. 
> 
> from my understanding, the patch for the above 1 has been committed into
> GCC9.

Yes.

> How about the patch for the above 2? has it been committed?

It has been there for a while, please take a look at:

$ gcov-tool merge --help
merge: unrecognized option '--help'
Merge subcomand usage:  merge [options] <dir1> <dir2>         Merge coverage
file contents
    -o, --output <dir>                  Output directory
    -v, --verbose                       Verbose mode
    -w, --weight <w1,w2>                Set weights (float point values)