[RFA] [4/5] Use DWARF-2 DW_AT_artificial information

[Jim Blandy]

Possibly clueless suggestion:

Couldn't we represent a method's arguments the same way we represent a
function's arguments?  That is, nfields would carry the number of
arguments, and fields[i] would describe the n'th field.  We could use
the `artificial' member of `union field_location' in `struct field' to
hold the information conveyed by DW_AT_artificial.

The fact that we've distinguished these has caused problems in the
past.  Check out the following code in hand_function_call:

  for (i = nargs - 1; i >= 0; i--)
    {
      /* Assume that methods are always prototyped, unless they are off the
	 end (which we should only be allowing if there is a ``...'').  
         FIXME.  */
      if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
	{
	  if (i < n_method_args)
	    args[i] = value_arg_coerce (args[i], TYPE_ARG_TYPES (ftype)[i], 1);
	  else
	    args[i] = value_arg_coerce (args[i], NULL, 0);
	}

      /* If we're off the end of the known arguments, do the standard
         promotions.  FIXME: if we had a prototype, this should only
         be allowed if ... were present.  */
      if (i >= TYPE_NFIELDS (ftype))
	args[i] = value_arg_coerce (args[i], NULL, 0);

      else
	{
	  param_type = TYPE_FIELD_TYPE (ftype, i);
	  args[i] = value_arg_coerce (args[i], param_type, TYPE_PROTOTYPED (ftype));
	}

Those two loops could be re-collapsed into one.