Re: [Patch, updated] Make emulated TLS lto-friendly.

[IainS <developer at sandoe-acoustics dot co dot uk>]

On 8 Jul 2010, at 00:22, Richard Henderson wrote:

> > +  /* If we need the var, and it's an emulated TLS entity, that
> > +     means we need the control var.  */
> > +  if (!targetm.have_tls && DECL_THREAD_LOCAL_P (node->decl))
> > +    {
> > +      struct varpool_node *cv_node;
> > +      cv_node = varpool_node (emutls_decl (node->decl)) ;
> > +      varpool_mark_needed_node (cv_node);
> > +    }
>
> Do you really need this kind of thing anymore, since you're exposing
> the use of the control variable so early?  I would have thought that
> varpool.c would no longer need any special-casing for !have_tls.

this is my understanding (which might be flawed &| incomplete).

Whilst we are on the parse side - and building varpool & cgraph, the  
relationship is not fully exposed (that happens when gimplication is  
done).

So my reasoning was that the "ghost/proxy" vars should be made to  
track the user-land ones until then.

It would be possible to put all the checks for 'used-ness' and  
finalization in emutls_finish() but it seemed more elegant to do so in  
the places I put it.

I'm happy either way ..

Iain