Re: RFC: Document unexpected behaviour of --fatal-warnings

["H.J. Lu" <hjl.tools@gmail.com>]

On Wed, Jan 24, 2024 at 7:15 AM Sam James <sam@gentoo.org> wrote:
>
>
> Nick Clifton <nickc@redhat.com> writes:
>
> > Hi Guys,
>
> Hi Nick,
>
> >
> >   It was recently pointed out to me that the bfd linker's
> >   --fatal-warnings option can behave in an unexpected manner.  For
> >   example:
> >
> >     $ ld.bfd -z bad-option --fatal-warnings -e 0/dev/null
> >     ld.bfd: warning: -z bad-option ignored
> >     $ echo $?
> >     0
> >
> >   ie the warning about the ignored option is not being treated as an
> >   error.  This happens because the --fatal-warnings option only takes
> >   affect after it has been processed, and we process the options in a
> >   linear order.  So the following works:
> >
> >     $ ld.bfd --fatal-warnings -z bad-option -e 0 /dev/null
> >     ld.bfd: warning: -z bad-option ignored
> >     $ echo $?
> >     1
> >
> >   This behaviour differs from gold and lld, both of which honour
> >   --fatal-warnings no matter where it occurs on the command line.
> >
> >   So we could fix the linker, create a two pass argument scan and the
> >   problem would be solved.  But a) I am lazy and b) we already have a
> >   precedent for options on the command line only affecting options that
> >   come after it.  (I am thinking of the -L option here, although there
> >   are probably several others).  So instead I am considering documenting
> >   the current behaviour as expected.  (See the patch below).
> >
> >   What do people think ?
>
> I'm OK with it either way. We're really used to this kind of linker
> behaviour so it's not a problem to just document it. I've not hit
> this as a problem at all.
>
> Then if someone wants to improve it later on, so be it.
>
> (We could maybe change the docs to say "may not affect" if we want
> leeway to change it later.)

I opened:

https://sourceware.org/bugzilla/show_bug.cgi?id=31289

and will submit a fix this week.

-- 
H.J.