DW_AT_containing_type

[David Carlton]

What's with GDB's and GCC's use of DW_AT_containing type?  As far as I
can tell, it's only supposed to be used within
DW_TAG_ptr_to_member_type, but GCC generates it and GDB uses it in
many other contexts.

I'll try to find time to figure out how we use it later, but I wanted
to raise the issue in case anybody knows the answer or in case other
people aren't aware that we seem to be misusing it.

David Carlton
carlton@kealia.com