[Bug lto/54962] Strange-looking diagnostics from diagnostic_report_current_module() from warnings emitted during LTO

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54962

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-18
     Ever Confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2012-10-18 09:55:45 UTC ---
(In reply to comment #0)
>   290          while (! MAIN_FILE_P (map))
>   291            {
>   292              map = INCLUDED_FROM (line_table, map);
> 
> This code appears to assume (via MAIN_FILE_P) that there is a concept of a main
> file, and that everything else is included from it.  However in the context of
> diagnostics emitted during LTO it's not clear that this concept makes sense (or
> maybe I'm missing something?  I also wonder if by attempting to issue
> diagnostics from within lto1 if I'm in unexplored territory here?)

You definitely are, if you are expecting everything to work just fine ;)

> This is called by default_tree_diagnostic_starter FWIW; perhaps lto1 needs its
> own implementation of this?

Maybe yes.  LTO should print the "main" file as well (so it doesn't have
a MAIN_FILE_P), but not as included-from but in some other way.

Patches welcome ;)