[cfe-dev] Warning flags

Ahmed Charles ahmedcharles at gmail.com
Thu Oct 6 14:10:08 PDT 2011

On Thu, Oct 6, 2011 at 1:16 PM, Ted Kremenek <kremenek at apple.com> wrote:
> On Oct 6, 2011, at 10:21 AM, Ahmed Charles wrote:
> I'm looking into adding flags for the various warnings without them and was
> wondering what the bar is in terms of test cases? It seems like existing
> flags don't have explicit test cases and in some cases neither do the
> warnings.
> Good questions.  These are two separate issues.  It's simply bad that we
> have warnings that aren't being tested at all (behaviorally).  For those we
> should continue to add test cases to improve our coverage of the compiler's
> behavior.
> For testing coverage of warning flags, the only thing you could really test
> from a behavior perspective is whether passing -W/-Wno<warning>
> enables/disables the warning (or use pragmas that accomplish the same
> thing).  Many warnings are on by default, so many of the tests would need to
> go for the "disable warning" route.  We are pretty confident that the
> general warning suppression/enabling mechanism works (it is well tested), so
> we only really need to add specific tests like these for warnings where it
> is clear we want to tease out some warning from a larger class of warnings
> and have the ability to disable it (e.g., a user explicitly requested this
> functionality).
> So, for testing whether or not a warning has a flag, we have
> test/Misc/warning-flags.c.  Essentially we run diagtool to list all the
> warnings that are not covered by a flag.  Whenever a warning that was
> previously not covered by a flag gets a flag, this test needs to be updated
> (i.e., remove the entry).  That's usually sufficient in my opinion to test
> that a warning is covered by a flag.

Thanks, that's what I thought.

Ahmed Charles

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