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Re: SHT_GROUP COMDAT


On Thu, Oct 16, 2003 at 09:36:25AM -0700, H. J. Lu wrote:
> On Thu, Oct 16, 2003 at 09:22:27AM -0700, Matt Austern wrote:
> > I plan to start working on SHT_GROUP COMDAT once I'm done with my
> > current work of enabling vague linkage for Darwin.
> > 
> > Unfortunately, group COMDAT may require some changes in binutils.
> > It has been implemented in binutils but, without compiler support,
> > it hasn't really been tested.  There may be some corner cases
> > that it doesn't quite get right.
> 
> Support multiple sections of the same name with section group is on
> my todo list:
> 
> http://sources.redhat.com/ml/binutils/2003-06/msg00295.html

So, there is no support for it in binutils yet?
H.J., the reason that I am interested in this subject is
because certain .gnu.linkonce* sections from different
compile units but containing the same template function
(or call method) instantiation, have each their own line
information being generated and put in the .debug_line
section (from ".loc ..." line in the .s file) by GNU as.
But the assembly code, and therefore the line number information
of these two instantiations can slightly differ.  GNU ld now
picks one instantiation, and an arbitrary .debug_line
part covering the function  - sometimes not the matching
one.

Therefore, one of the things that is needed is that 'GNU as'
needs to generate section groups for the .debug_line sections,
of .gnu.linkonce* "instantiations", linking the ones that belong
together.

Sorry if I am being unclear - it is not clear to myself
how this should be solved.  But it seem specific enough
to need special attention;  I was wondering if this will
be on your todo list too :).

-- 
Carlo Wood <carlo@alinoe.com>


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