Re: Regression on prelinked-sepdebug-shlibs

[Jan Kratochvil <jan.kratochvil@redhat.com>]

Hi Tristan,

On Wed, 06 Jan 2010 17:38:55 +0100, Tristan Gingold wrote:
> do you have a patch for dwarf2read.c(dwarf2_psymtab_to_symtab) ?
> 
> 	  /* If this psymtab is constructed from a debug-only objfile, the
> 	     has_section_at_zero flag will not necessarily be correct.  We
> 	     can get the correct value for this flag by looking at the data
> 	     associated with the (presumably stripped) associated objfile.  */
> 	  if (pst->objfile->separate_debug_objfile_backlink)
> 	    {
> 	      struct dwarf2_per_objfile *dpo_backlink
> 	        = objfile_data (pst->objfile->separate_debug_objfile_backlink,
> 		                dwarf2_objfile_data_key);
> 	      dwarf2_per_objfile->has_section_at_zero
> 		= dpo_backlink->has_section_at_zero;
> 	    }
> 
> I think this is not correct: the separate debug file may have one section at
> zero while the main may not.  In the above code, we do not consider wether
> an offset is used.
> 
> I am not sure that this can happen with ELF however.

This has_section_at_zero feature is intended for embedded targets.  I only
know has_section_at_zero can never happen for cases I am aware of.

IMHO embedded targets do not use the file-vs-memory offsets but not sure.
Also the embedded targets probably do not use .linkonce/COMDAT - this is why
this has_section_at_zero differentiator could work.

[PATCH] Allow dwarf2 debug info for function at address 0
http://sourceware.org/ml/gdb-patches/2006-07/msg00291.html


Regards,
Jan