https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47618
--- Comment #28 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #26)
> (In reply to qinzhao from comment #25)
> > (In reply to Martin Liška from comment #24)
> > >
> > > > 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)
> >
> > two more questions on this merge tool:
> > 1. it can only merge two directories at one time. So, for multiple
> > directories, for example "n", we have to invoke gcov-tool merge n-1 times in
> > order to merge all of them?
>
> Yep. I guess one can write a simple bash script that does that.
>
> > 2. Intel compiler (icc)'s profmerge is able to merge all the .dyn files
> > under one directory, does gcc have such functionality currently?
>
> We have folder-base merging where we search for all .gcda files and we merge
> them to a destination folder.
$ echo "int main() {return 0;}" >> main.c && gcc --coverage main.c && ./a.out
$ mkdir a && mkdir b && cp main.gcda c && cp main.gcda b
$ gcov-tool merge a b -o a+b -v
reading file: ./main.gcda
tag one function id=108032747
reading file: ./main.gcda
tag one function id=108032747
$ ls a+b
main.gcda
$ gcov-dump a+b/main.gcda
a+b/main.gcda:data:magic `gcda':version `A83*'
a+b/main.gcda:stamp 2031787297
a+b/main.gcda: a3000000: 22:PROGRAM_SUMMARY checksum=0x33c369a8
a+b/main.gcda: counts=1, runs=1, sum_all=2, run_max=2, sum_max=2
a+b/main.gcda: counter histogram:
a+b/main.gcda: 2: num counts=1, min counter=2, cum_counter=2
a+b/main.gcda: 01000000: 3:FUNCTION ident=108032747,
lineno_checksum=0x3b5ee2be, cfg_checksum=0xdb5de9e8
a+b/main.gcda: 01a10000: 2:COUNTERS arcs 1 counts
