[vta->trunk] VTA merge

[Mark Mitchell]

Jakub Jelinek wrote:

>>> I don't know about other debuggers, but GDB will issue an error like:
>>>
>>>     Unhandled dwarf expression opcode 0x9e
>>>
>>> if you try to print a variable whose location uses that opcode.
>> That's unfortunate.  Obviously, we can't do anything about older
>> versions of GDB, but can we change GDB so that it doesn't complain and
>> just silently ignores the expression, unless in some debugging mode? 
> 
> Yes, it is unfortunate.  But we can't retroactively change released GDBs,
> and the upcoming GDB will understand it.  And you need the upcoming GDB to
> debug GCC 4.5 compiled code anyway, because older GDBs mishandle
> DW_CFA_restore_state which is now used all around in .eh_frame, otherwise
> backtraces really don't work.

Yes, I understand; nothing we can do for 4.5.  But, I'd like to hear
that we're fixing GDB so that if GCC (or some other compiler) introduces
new DWARF opcodes in future we won't have a similar problem.

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713