Re: Generating code coverage reports

[Ludovic Courtès]

Hi Ralf,

Ralf Wildenhues <address@hidden> writes:

> Hello Ludovic, Simon,
>
> * Ludovic Courtès wrote on Tue, Oct 28, 2008 at 05:48:12PM CET:
>> 
>> Let me explain this.  Suppose you have tests T1 and T2:
>> 
>>   * T1 uses code from foo.c and t1.c;
>>   * T2 uses code from foo.c and t2.c.
>> 
>> Running "make check" runs T1, then T2:
>> 
>>   * T1 is run, producing foo.gcda and t1.gcda;
>>   * T2 is run, *overriding* foo.gcda and producing t2.gcda.
>> 
>> In the end, `lcov' is fed with foo.gcda from the T2 run, whereas what we
>> really want to have is the code covered in foo.c by T1 *and* T2.
>
> That's not what my GCC documentation says (info gcc 'Invoking Gcov',
> near the end):
>
>    The execution counts are cumulative.  If the example program were
>   executed again without removing the `.gcda' file, the count for the
>   number of times each line in the source was executed would be added to
>   the results of the previous run(s). [...]

Oh, you're right.  The GCC 4.2 manual contains the same paragaph:
http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Invoking-Gcov.html#Invoking-Gcov .

Sorry for the confusion.

> FWIW, IIRC then the directory handling of the files was only fixed to be
> sane rather recently in the GCC tree (I guess 4.4 only).

By "directory handling", you mean the location where GCDA files are
produced relative to the location of the corresponding `.o' files?

Thanks,
Ludo'.