C++ and multiple compilation units

[Jim Blandy]

Dan, a while back I think you mentioned a problem that would only
appear when debugging C++ programs using Dwarf 2 debug info that used
multiple compilation units.  I think the issue was that our current
dwarf 2 reader doesn't really handle inter-CU DIE references, and that
GCC was going to start generating them.  Our current C++ tests
probably won't catch such a problem --- almost all of the test
programs are a single CU.

Can you give more details on this?  Does GCC generate these inter-CU
references now?  For what sorts of constructs?  Do you have a test
case?