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Re: C++ debugging progress
On Wed, Nov 28, 2001 at 07:40:37PM +0000, Jason Merrill wrote:
> >>>>> "Daniel" == Daniel Jacobowitz <firstname.lastname@example.org> writes:
> > On Wed, Nov 28, 2001 at 09:31:07AM +0000, Jason Merrill wrote:
> >> So you're using the inheritance information in the RTTI rather than the debug
> >> info? That seems unfortunate. I'm not sure why you would need to worry
> >> about ordering; the debug info should tell you exactly where things are.
> >> If it doesn't, it should probably be fixed.
> > In that case, the debug info absolutely needs to be fixed.
> > <1><22e>: Abbrev Number: 15 (DW_TAG_structure_type)
> > DW_AT_sibling : <2df>
> > DW_AT_name : Left
> > DW_AT_byte_size : 12
> > DW_AT_decl_file : 1
> > DW_AT_decl_line : 2
> > DW_AT_containing_type: <22e>
> > <2><23f>: Abbrev Number: 22 (DW_TAG_inheritance)
> > DW_AT_type : <56>
> > DW_AT_data_member_location: 2 byte block: 23 8 (DW_OP_plus_uconst: 8; )
> > DW_AT_virtuality : 1 (virtual)
> > DW_AT_accessibility: 1 (public)
> Yep. Since Base is a virtual base of Left, the DW_AT_data_member_location
> here should be a complex expression telling the debugger to go through the
> vtable. I'll get on it.
> I'll also change the stabs output to give the offset within the vtable
> rather than the offset of the base in a complete object; gdb will still
> need to be clever enough to know what to do with it.
I should add: is there some way we can disambiguate correct and
incorrect debug info after this fix? For Dwarf2 I see how to do it
pretty easily. Would an explicit minus sign work? I think GDB won't
croak on that.
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer