Re: [debug-early] fix problem with template parameter packs

[Aldy Hernandez <aldyh at redhat dot com>]

On 06/04/2015 02:39 PM, Jason Merrill wrote:
> On 06/04/2015 02:23 PM, Jason Merrill wrote:
> > On 06/03/2015 10:42 AM, Aldy Hernandez wrote:
> > > +  /* Die was generated early via dwarf2out_early_global_decl.  */
> > > +  BOOL_BITFIELD dumped_early : 1;
> >
> > Missed a "dump".
> >
> > Actually, why do we need this flag?  The uses I see are
> >
> > * to avoid declaring prototype parameters multiple times

It used to verify the sanity of the late limbo list.  I can remove this 
though if you want.

dwarf2out_decl() also has a sanity check to verify that early dumped 
DIEs are not generated again.  I can remove this as well if you prefer.

And finally, I believe the big block you speak of below has a check for 
dumped_early, that may or may not allow it to distinguish for things 
that happen in LTO which still acts like traditional late dwarf.  I 
haven't checked this though... but if you want it removed I can check 
and retest.

> > Can't we just assume that if we have an old DIE, it already has
> > parameters?
> >
> > * to make the logic in gen_variable_die even more horrible
> >
> > It's really not clear to me that we need the new big block of code.  I
> > would think that it should be enough to update this:
> >
> > >    /* If the compiler emitted a definition for the DECL declaration
> > > +     and we already emitted a DIE for it, don't emit a second
> > >       DIE for it again. Allow re-declarations of DECLs that are
> > >       inside functions, though.  */
> > > -  if (old_die && declaration && !local_scope_p (context_die))
> > >      return;
> >
> > to add locations instead of just returning when !early_dwarf.
> >
> > Incidentally, why did you change "declaration" to "!declaration" in this
> > condition?
>
> Ah, wait.  If we revert that mysterious change, it's clear again that
> this check is just dealing with avoiding duplicate declarations, so
> within this condition isn't the right place for adding locations to
> early DIEs; that should probably happen right after this.

This was in Michael Matz's original prototype.  I'm surprised it 
survived this long.

So... if I revert the !declaration change and move the big block below 
said change, would you be OK with it, or did you still want some changes 
to it?

Aldy