Ping: RFC: add dwarf support for xcoff/AIX

[Richard Sandiford]

Tristan Gingold <gingold@adacore.com> writes:
>> * because section names are limited to 8 characters, the standard
>> dwarf names cannot be used.  XCOFF defines alternate names (.dwinfo,
>> .dwline...)  But to simplify the interface with gdb and objdump, the
>> xcoff back-end automatically canonicalize the names to the standard
>> dwarf names.  To do this I added a coff hook (expand_section_name)
>> and a new coff macro (adjust_scnhdr_before_swap).  Not sure that this
>> conversion is a good idea, so comments are welcome here.

I can see the attraction of this, but does it mean that objcopy and
objdump operations on the original ("real") sections won't work?
That might be a bit confusing for human (rather than scripted)
users of the tools.  Especially if you use the AIX and GNU tools
together.

An alternative might be to have a pointer to a table of section names
in the bfd_target structure.  We could then replace direct uses of
".debug_frame" etc. with uses of accessor macros.  What do others think?

>> * AIX as has a special pseudo for declaring dwarf sections: .dwsect
>> However this pseudo does prepend the size.  As this is very unusual
>> (and would require more work in gcc), I choose to not implement it
>> and to use the standard .section semantic (which was already present
>> for convenience).  Of course, nothing prevents from adding .dwsect
>> later (the difficult part would be in gcc)

That's fair enough, but it could also be added to gas with the gcc side
left as future work.

Richard