https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89959
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2019-04-04
Assignee|unassigned at gcc dot gnu.org |marxin at gcc dot
gnu.org
Target Milestone|--- |9.0
Ever confirmed|0 |1
--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Hi.
Thank you very much for using the GCOV.
>
> a) Running "gcov -r -s <source_dir> -o <object directory> <.gcda file>" I
> get files like
>
> <source file>.gcov
>
>
> b) Running "gcov -p -r -s <source_dir> -o <object directory> <.gcda file>" I
> get files like
>
> <relative path to the source file>.gcov
>
>
> c) Running "gcov -x -r -s <source_dir> -o <object directory> <.gcda file>" I
> get files like
>
> <source file>##<hash>.gcov
>
>
> d) Running "gcov -p -l -r -s <source_dir> -o <object directory> <.gcda
> file>" I get files like
>
> <full path to the .gcda file>##<relative path to the source file>.gcov
>
>
> e) Running "gcov -x -l -r -s <source_dir> -o <object directory> <.gcda
> file>" I get files like
>
> <source file>##<hash>.gcov
>
>
>
> Notice that 'c' and 'e' are identical, "-l" in 'e' has had no effect. I
> would have expected 'e' to be
>
> <full path to the .gcda file>##<source file>##<hash>.gcov
>
>
>
> Also, notice that the documentation for --hash-filenames starts by saying:
> "By default, gcov uses the full pathname of the source files to create an
> output filename." That's incorrect, by default it uses only the filename.
Correct, I'll fix that in documentation.
> The documentation would be more clear if it would describe
> "--hash-filenames" as an alternative to "--preserve-paths".
Exactly, the documentation describes problem of long file-names, but it should
make it clear that -l would be ignored.
Interestingly,
> when "-x" is being used "-l" is ignored... but "-p" isn't. So it's possible
> to use "-p" and "-x" simultaneously, which makes no sense. You are using
> "-x" to avoid long filenames, but by using it together with "-p" you are
> just making the filename *longer*.
You are right, -p should be also ignored in case of -x usage.
>
>
>
>
> FWIW the reason I'm using "-l" is not because I "want to see the individual
> contributions". My problem is that I'm using CDash (www.cdash.org), which
> runs gcov once per .gcda instead of running it a single time taking all the
> .gcda files as input (they should fix this
> https://gitlab.kitware.com/cmake/cmake/issues/19124#note_554321, but there
> may be others).
> By running gcov once per .gcda file the .gcov file for a header created by
> one invocation can get overwritten by the next .gcov invocation. Using "-l"
> works around this issue.
> Again, the problem is that CDash is using gcov incorrectly and they should
> fix the issue. But since I suspect they are not the only ones... maybe it
> makes sense to have another option to use the hash of the .gcda file?
> Meaning, running "gcov -x --hash-long-file-names -r -s <source_dir> -o
> <object directory> <.gcda file>" I would get files like
>
> <gcda_path_hash>##<source file>##<source_file_path_hash>.gcov
Please now, even now the complexity of option combination is quite huge :)
>
> Which would let me, using short file names, call gcov once per .gcda file
> without the risk of overwriting .gcov files.
Then I would recommend using -l option.
