Re: DWARF question/inlining/local classes

[Geoff Keating <geoffk at geoffk dot org>]

> Date: Wed, 30 Oct 2002 17:53:05 -0800
> From: Mark Mitchell <mark@codesourcery.com>

> --On Wednesday, October 30, 2002 04:44:12 PM -0800 Geoff Keating 
> <geoffk@geoffk.org> wrote:
> 
> > Mark Mitchell <mark@codesourcery.com> writes:
> >
> >> PR 8391 contains this code:
> >>
> >>    inline void h(const Outer &o)
> >>    {
> >>      struct Local : public Outer::Inner {
> >> 	 virtual bool f() {};
> >>      };
> >>      Local l;
> >>      o.g(l);
> >>    }
> >>
> >> When we try to emit the body of Local::f (the function in the struct
> >> inside h), we don't actually emit assembly code because of this code
> >> in rest_of_compilation:
> >>
> >>       /* If this is nested inside an inlined external function, pretend
> >> 	 it was only declared.  Since we cannot inline such functions,
> >> 	 generating code for this one is not only not necessary but will
> >> 	 confuse some debugging output writers.  */
> >>       for (parent = DECL_CONTEXT (current_function_decl);
> >> 	   parent != NULL_TREE;
> >> 	   parent = get_containing_scope (parent))
> >> 	if (TREE_CODE (parent) == FUNCTION_DECL
> >> 	    && DECL_INLINE (parent) && DECL_EXTERNAL (parent))
> >> 	  {
> >> 	    DECL_INITIAL (decl) = 0;
> >> 	    goto exit_rest_of_compilation;
> >> 	  }
> >>
> >> This logic is wrong for C++; we need to emit Local::f.
> >
> > I believe the rationale behind this code is that Local::f can't be
> > used from this translation unit, since the function won't be inlined.
> > It will be emitted when the out-of-line copy of the function is emitted.
> >
> > Will this function really not be inlined?
> 
> The function will indeed be inlined in this translation unit.

That's what I thought.  I bet this comment dates from the time of the
RTL inliner, which (no doubt) really couldn't inline such functions.
It's possible that this code is obsolete and should go away.

-- 
- Geoffrey Keating <geoffk@geoffk.org>