Re: [RFC] analyzer: Add exit, and _exit replacement, to sm-signal.

[David Malcolm via Gcc-patches]

On Sun, 2020-05-17 at 18:42 -0400, David Malcolm via Gcc-patches wrote:
> On Sun, 2020-05-17 at 18:39 -0400, David Malcolm via Gcc-patches
> wrote:
> > On Mon, 2020-05-18 at 00:05 +0200, Mark Wielaard wrote:
> 
> [...snip...]
> 
> > How about something like this (though I even haven't checked if it
> > compiles, and am not 100% sure what the wording should be):
> > 
> >   bool emit (rich_location *rich_loc) FINAL OVERRIDE
> >   {
> >     diagnostic_metadata m;
> >     /* CWE-479: Signal Handler Use of a Non-reentrant Function.  */
> >     m.add_cwe (479);
> 
> ...and there should be this here:
>       auto_diagnostic_group d;
> 
> to associate the note with the warning.
> 
> >     if (warning_meta (rich_loc, m,
> >                   OPT_Wanalyzer_unsafe_call_within_signal_handler,
> >                   "call to %qD from within signal handler",
> >                   m_unsafe_fndecl))
> >       {
> >     if (m_replacement)
> >       {
> >         gcc_rich_location note_rich_loc (gimple_location
> > (m_unsafe_call));
> >         note_rich_loc.add_fixit_replace (m_replacement);
> >         inform (&note_rich_loc, "%qs is a signal-safe replacement
> > for %qD",
> >                 m_replacement, unsafe_fndecl);
> >       }
> >     return true;
> >       }
> >     return false;
> >   }

Also, m_unsafe_fndecl is a field of signal_unsafe_call, so we can delay
calling replacement_fn until inside signal_unsafe_call::emit, after the
warning has been emitted.

It could even become a member function of signal_unsafe_call, giving
something like this for signal_unsafe_call::emit:


  bool emit (rich_location *rich_loc) FINAL OVERRIDE
  {
    auto_diagnostic_group d;
    diagnostic_metadata m;
    /* CWE-479: Signal Handler Use of a Non-reentrant Function.  */
    m.add_cwe (479);
    if (warning_meta (rich_loc, m,
                      OPT_Wanalyzer_unsafe_call_within_signal_handler,
                      "call to %qD from within signal handler",
                      m_unsafe_fndecl))
      {
        if (const char *replacement = get_replacement_fn ())
          {
            gcc_rich_location note_rich_loc (gimple_location (m_unsafe_call));
            note_rich_loc.add_fixit_replace (replacement);
            inform (&note_rich_loc, "%qs is a signal-safe replacement for %qD",
                    replacement, m_unsafe_fndecl);
          }
        return true;
      }
    return false;
  }