Re: [RFC Patch 0/5] gcov: integrate gcov into kbuild

[Peter Oberparleiter <oberpar@linux.vnet.ibm.com>]

Amerigo Wang wrote:
> This patchset is mainly to integrate gcov into kbuild system, so that
> we can use "make foo/bar.c.gcov" to get the gcov files.
> Also moves the useful scripts in gcov.txt into tools/gcov/ direcotry.

Interesting approach - this should definitely make it more easy for 
developers to get coverage data for their code. A couple of 
thoughts/observations:

- does not work when compiling with a separate build directory (make O=)

/sys/kernel/debug/gcov//mnt/out//mnt/linux-2.6.gcno:cannot open graph file
make[2]: *** [init/main.c.gcov] Error 1
make[1]: *** [init/main.c.gcov] Error 2
make: *** [sub-make] Error 2

This is most likely due to target_base_name being an absolute path 
(relative to srctree) in case build and source directories are different.

- gcov call should use option -p, otherwise gcov may overwrite .gcov 
files if a .c file includes two .h files from different directories.
- an option to generate .gcov files for all .c files in a subdirectory 
would be nice


Regards,
   Peter Oberparleiter