[tree-ssa] Reorganize expansion of nested functions

[Jan Hubicka]

> On Sun, Feb 01, 2004 at 03:25:53AM +0100, Jan Hubicka wrote:
> > + /* PARAM is function parameter referenced by nested function, prepare to
> > +    produce correct code in that case.  */
> > + void
> > + notice_parameter_referenced_by_nested_function (tree param ATTRIBUTE_UNUSED)
> > + {
> > + #ifdef NEED_SEPARATE_AP
> > +   get_arg_pointer_save_area (cfun);
> > + #endif
> > + }
> 
> Why is this needed?  Indeed, I would expect basically all of this:

It is needed to make it possible to access the argument by nested
functions.  There is corresponding code in function.c

      /* If reached via arg pointer, get the arg pointer value
	 out of that function's stack frame.

	 There are two cases:  If a separate ap is needed, allocate a
	 slot in the outer function for it and dereference it that way.
	 This is correct even if the real ap is actually a pseudo.
	 Otherwise, just adjust the offset from the frame pointer to
	 compensate.  */

#ifdef NEED_SEPARATE_AP
      rtx addr;

      addr = get_arg_pointer_save_area (fp);
      addr = fix_lexical_addr (XEXP (addr, 0), var);
      addr = memory_address (Pmode, addr);

      base = gen_rtx_MEM (Pmode, addr);
      set_mem_alias_set (base, get_frame_alias_set ());
      base = copy_to_reg (base);
#else
      displacement += (FIRST_PARM_OFFSET (context) - STARTING_FRAME_OFFSET);
      base = lookup_static_chain (var);
#endif
> 
> > ! examine_nested_functions_1 (tree * tp, int *walk_subtrees, void *data)
> 
> to be handled by rtl expansion of the parent function.

It is done by rtl expansion of nested function that hooks it into parent
function if I understand it right.  But I can move the walk around into
the expansion somewhere.
> 
> >     expand_function_end ();
> > + 
> > +   expand_nested_functions ();
> 
> As far as I can see, moving expansion of nested functions here
> from expand_used_vars is the only substantive change.

Yes, the other stuff is needed to make it work :)

Honza
> 
> 
> r~