Deprecate -funit-at-a-time

[Jan Hubicka]

> On Fri, Jul 18, 2008 at 08:14:40PM +0200, Richard Guenther wrote:
> > On Fri, Jul 18, 2008 at 7:29 PM, Jan Hubicka <hubicka@ucw.cz> wrote:
> > >> Richard Guenther wrote:
> > >> Why -fno-section-anchors?
> > >
> > > See Jakub's message.
> > 
> > I agree with Mark.  -fno-toplevel-reorder should imply
> > -fno-section-anchors instead.
> 
> Explicit -fno-toplevel-reorder should imply -fno-section-anchors, but didn't
> Honza want to make -fno-toplevel-reorder the default at -O0 (or is it
> already)?  If yes, perhaps the PPC folks wouldn't be happy that
> -fno-section-anchors is used for -O0.

I enabled it at O0 already.  For C ti didn't seem appropriate to do
implicit reordering or to drop unused static vars.  It has turned out to
be interesting at least in keeping -fno-toplevel-reorder working, it had
uncovered nuber of bugs.

Well, I guess we have concensus on following:

 1) keep -funit-at-a-time option forever implying -fno-toplevel-reorder
 2) explicit -fno-toplevel-reorder imply -fno-section-anchors
    (I can imagine use of ASM statements that is compatible with anchors
    but you don't want other changes of -fno-toplevel-reprder)
 3) explicit -fno-topelvel-reoder and -fsection-anchors should error.

I can make -O0 just to enable -fno-toplevel-reorder but no anchors, or I
can drop -fno-toplevel-reorder from -O0 whatever seems more appropriate.

To make -funit-at-a-time to cancel -fno-unit-at-a-time, I guess I am
stick with keeping the option and handling everything in opts.c, right?
(that is init flag_section_anchors and flag_toplevel_reorder to 2 and
handle the defaults by hand).

Seems sane?
Honza
> 
> 	Jakub