Re: [patch] stop objcopy breaking group sections

[Andrew Stubbs <ams at codesourcery dot com>]

Alan Modra wrote:
> Nope.
>
> The ELF spec says sh_info for SHT_GROUP is:
>
> The symbol table index of an entry in the associated symbol table. The
> name of the specified symbol table entry provides a signature for the
> section group.
>
> Since the section name is changed to the group name, it should be
> possible to use the section symbol as the id symbol.  Doesn't look
> like a "wrong symbol" or "broken" to me.  If ld is having trouble
> linking such a group, then we need to fix ld.

OK, I'll admit that I do not fully understand how this mechanism works. 
The code is less than easy to understand, and it doesn't help that it 
doesn't even attempt to do copies precisely.

On a second examination it does seem that the value of sh_info is 
meaningful, although confusingly it doesn't use the same value that the 
original file had (and I still can't see the mechanism by which it 
calculates this value).

But I can't decide if this is "wrong" or not. Your quote said "The name 
of the specified symbol table entry provides a signature for the section 
group." In this case readelf does not display a name for the symbol. It 
is this anonymity that is causing the problem, but I don't know why yet.

Hmmm, I'm going to have to go away and think about this one some more.

Thanks

Andrew