Section garbage collection problem

[H.J. Lu]

On Wed, Sep 19, 2007 at 09:34:24PM +0100, Denys Vlasenko wrote:
> 
> Well, ... what is comdat group?...

# info as

and search for comdat.

> 
> I'm not sure that I explained it well enough, so
> a bit of clarification: I don't try to make ld --gc-sections
> discard .text.unused and .smp_locks.BBBB in this situation:
> 
> ... -> .text.f_used -> .smp_locks.AAAA -> .text.f_used
>        .text.unused -> .smp_locks.BBBB -> .text.unused
> 
> because it is already working.
> 
> My problem is how to _make section dependency graph look
> like above_, because currently it looks like
> 
> ... -> .text.f_used -> .smp_locks.AAAA -> .text.f_used
>        .text.unused -> .smp_locks.AAAA -> .text.unused
> 
> In this graph, .text.unused is erroneously seen as "used" by ld,
> because two ".smp_locks.AAAA" sections are coalesced into one
> (because I cannot produce unique section name... see the first
> message in the thread).

With comdat group, you can have sections with the same section name,
but different signature.


H.J.