Message-ID: <4AA4C354.4040002@linux.vnet.ibm.com>
Date: Mon, 07 Sep 2009 10:24:52 +0200
From: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
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To: Amerigo Wang <amwang@redhat.com>
CC: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
       linux-kbuild@vger.kernel.org, Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [RFC Patch 0/5] gcov: integrate gcov into kbuild
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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

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