Hello Bernd,
On Wed, Mar 05, 2008 at 11:08:04AM +0200, Bernd Jendrissek wrote:
> I'm worried that when I do gcov *.o, gcov might not notice that two
> objects are derived from the same file, and thus the coverage notes
> might reflect coverage only of a subset of the use cases - those that
> exercise foo.c through ${bindir}/bar but not those that exercise it
> through ${bindir}/baz.
> Are there any guarantees (or specific lack thereof) about gcov's
> behaviour under these circumstances?
"gcov bar.o baz.o" ->
gcov bar.o reads bar.gcno and bar.gcda, then writes output into foo.c.gcov
gcov baz.o reads baz.gcno and baz.gcda, then writes output into foo.c.gcov
(overwriting the first foo.c) (tested with gcc-3.4.4)
(Although it is built in into the gnu coverage framework to be able to
add up counts this from different runs of the *same* executable, this
is done at the gcda level and not at the foo.c.gcov level, possibly with
the intention to keep things simple.)
Solution: use lcov from the linux test project that has adding
up functionality at the *.c.gcov level (internally it just uses
the same gcov framework)
(Let's assume that bar contains bar.o and baz contain baz.o)
lcov --zerocounters
./bar
lcov --capture --output-file barbaz.info
./baz
lcov --capture --output-file barbaz.info
genhtml barbaz.info
HTH,
--
Holger Blasum AT www.sysgo.com
