[Bug c/49702] Undefined static functions resolve to external definitions

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49702

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-11 
11:53:06 UTC ---
Warning code in question:

toplev.c:
void
check_global_declaration_1 (tree decl)
{
  /* Warn about any function declared static but not defined.  We don't
     warn about variables, because many programs have static variables
     that exist only to get some text into the object file.  */
  if (TREE_CODE (decl) == FUNCTION_DECL
      && DECL_INITIAL (decl) == 0
      && DECL_EXTERNAL (decl)
      && ! DECL_ARTIFICIAL (decl)
      && ! TREE_NO_WARNING (decl)
      && ! TREE_PUBLIC (decl)
      && (warn_unused_function
          || TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))))
    {
      if (TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
        pedwarn (input_location, 0, "%q+F used but never defined", decl);
      else
        warning (OPT_Wunused_function, "%q+F declared %<static%> but never
defined", decl);
      /* This symbol is effectively an "extern" declaration now.  */
      TREE_PUBLIC (decl) = 1;
      assemble_external (decl);
    }