GCC testsuite philosophy?

[Stan Shebs <shebs at apple dot com>]

I'm preparing some additional Objective-C testcases to ensure that my
tinkering with the frontend is not causing regressions, but I'm not
clear on the preferred organization, or perhaps there isn't any. :-)

In particular, I want to add compile and noncompile tests for ObjC,
a la gcc.c-torture.  For both of these, I want to be able to match
on warnings and errors.

For noncompile tests, I was able to make an objc-dg.exp and get
reasonable results, except that it runs each test at different
optimization levels, which seems kind of pointless, since the
compiler errors out during parsing.  So is that really how tests for
compilation errors are supposed to work?

For compile tests, I wanted to get a warning and match on it to
make sure it's the right message, but it seems that the c-torture
expect script always passes -w, which kind of defeats the purpose. :-)
This leaves me wondering if I'm missing something obvious, or do
I have to use objc-dg.exp here also?

Also, I need to come up with a way to test some of the objc/
tests one way when using the NeXT-derived runtime in OS X, and
a different way when using the libobjc&GNUstep runtime.  Presumably
I can arrange this similarly to how multiple optimization options
are handled; site.exp hackery seems too heavy-duty.

Finally, are the arguments to dg-warning and dg-error documented
anywhere?

Stan