[PATCH] Set a debugger "target" to guide DWARF choices

[Robinson, Paul]

> > On Darwin this is for two reasons:
> > 
> > 1) LLDB is the default debugger & can't cope with this debug info
> > 2) Apple ships a device driver API without debug info - that API 
> > includes a base class that drivers will derive from. The base class's 
> > debug info is missing in this situation.

Sounds like -fstandalone-debug is really (LLDB || Darwin) because there's
a platform consideration as well as a debugger consideration.

> > What's the motivation on FreeBSD? Is LLDB the default debugger there
> 
> We're on track to have LLDB as the default debugger in the FreeBSD
> base system. Right now we have both GDB 6.1.1 and LLDB 3.6 in the
> tree. The obsolete version of GDB we've got is not particularly useful
> at this point, and it remains only until the kernel debugging support
> is resolved in LLDB and in GDB in the ports tree.
> 
> > (considered fixing LLDB?)
> 
> I'd love to eventually, but there's a large number of items ahead of
> that on my list.

The -fstandalone-debug defaulting is currently triple-based and done in
the frontend.  I kinda think its scope is confined to Clang?
Which is a whole 'nother can of worms, but I'll make a note of this for
the moment when I can't put off opening that one.
Thanks,
--paulr