Re: [committed][gdb/testsuite] Update psym-external-decl.exp for gcc-10/clang

[Gary Benson <gbenson@redhat.com>]

Tom de Vries wrote:
> On 6/19/20 4:00 PM, Gary Benson wrote:
> > Tom de Vries wrote:
> > > On 6/18/20 6:10 PM, Gary Benson wrote:
> > > > Tom de Vries wrote:
> > > > > On 6/17/20 2:24 PM, Gary Benson wrote:
> > > > > > Tom, I'd like this testcase to not fail silently.  Is the
> > > > > > functionality under test something that isn't ever
> > > > > > expected to work with clang, or is this a test that should
> > > > > > pass with clang (but it currently doesn't, for whatever
> > > > > > reason)?
> > > > >
> > > > > I'm not sure.  The test can pass with clang, provided it
> > > > > generates the required debug info.  It currently doesn't.
> > > > > Why that is the case, I have no idea.
> > > >
> > > > I think that means the test should work but it doesn't.  Would
> > > > you object if I push a patch removing the test-skipping logic?
> > > > It will mean an extra FAIL when tested using clang
> > >
> > > I don't think having a fail for a compiler bug/missing-feature
> > > is a good idea.
> > >
> > > If this is due to a bug/missing-feature in clang, then we need to:
> > > - xfail the test,
> > > - file the PR in clang, and
> > > - reference the PR at the xfail.
> > 
> > Is this a bug/missing feature in clang though?
> > How sure are you GDB isn't at fault?
> 
> Clang emits less debug info than GCC.  Whether that's a bug, a
> missing feature or an explicit unsupported feature in clang, I
> don't known.
> 
> I known that gdb isn't at fault.  It can't do anything without the
> missing debug info.  The test was specifically written to use that
> debug info.

I'm not really sure what's the right thing to do here.

On the one hand, my current task is ensuring GDB can debug
clang-compiled with clang as well as it can debug GCC-compiled
code.  From that perspective the skip-if-clang logic in this
test is hiding a failure I need to investigate.

On the other hand, I'm an engineer working on GDB, and from that
perspective I want to be able to run the GDB testsuite and see
100% pass, on whatever setup I test it on.  And yes, I know it
doesn't... but it *should*.

Is there a way to pass a "don't skip clang failures" flag to the
testcases, such that people running the testsuite normally would
see tests like these return UNSUPPORTED, but I could run the
testsuite with the flag so it'd not skip but FAIL wherever the
problem is?

Thanks,
Gary

-- 
Gary Benson - he / him / his
Principal Software Engineer, Red Hat