Re: Should the section address be ignored when processing DWARF information ?

[Corinna Vinschen <vinschen at redhat dot com>]

Hi Nick & Eric,

On Apr 20 13:44, Nick Clifton wrote:
> >>  Does Mach-O need to have the section address added in to the offset
> >>  calculation when processing DWARF information ?
> >
> >Right now dwarf information is only used in object files which are a 
> >single "section", that then the actual sections are offsets within that 
> >so unfortunately, yes, it needs the section address added into the 
> >offset calculation when processing dwarf in object files.
> 
> Darn.
> 
> >Out of 
> >curiosity what is the section offset in the coff/pe files? I would think 
> >it would be something similar...
> 
> Corinna can probably answer this better than I, but I believe that the 
> dwarf sections in PE files are given addresses after the end of all the 
> other data.  (See ld/scripttempl/pe.sc).  They do not have the Mach-O 
> problem however, because the offsets are all section relative to the 
> start of the real debug sections, not Mach-O's mega-section.

The PE/COFF format on x86 Windows requires that every section in a file
starts on the next 4K boundary after the end of the previous section.
Therefore, even though debug sections are marked as NOLOAD sections,
they have to have a valid VMA address according to that rule.  Otherwise
the Windows runtime loader complains that the binary is not a valid
executable image.

> So - Eric, Corinna - please could you try out the attached,
> alternative patch ?

Works fine for Cygwin.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Project Co-Leader
Red Hat