Re: [PATCH/RFC] Per-architecture DWARF CFI register state initialization hooks

[Daniel Jacobowitz <drow@false.org>]

On Mon, Feb 16, 2004 at 02:01:29PM +0100, Ulrich Weigand wrote:
> Daniel Jacobowitz wrote:
> 
> > On Mon, Feb 16, 2004 at 02:27:24AM +0100, Ulrich Weigand wrote:
> > > +void
> > > +dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
> > > +                          void (*init_reg) (struct gdbarch *, int,
> > > +                                            struct dwarf2_frame_state_reg *))
> > 
> > > Unfortunately this now crashes on s390, because the 
> > > dwarf2_frame_init routine is called from within
> > > _initialize_dwarf2_frame, while the s390 backend calls
> > > dwarf2_frame_set_init_reg from within _initialize_s390_tdep.
> > 
> > Er, how?  You shouldn't have a gdbarch in _initialize_s390_tdep.  You
> > don't have one until s390_gdbarch_init.
> 
> Sorry, my analysis wasn't completely correct.  What actually happens
> is an init-order problem during the initialization of the gdbarch
> in initialize_current_architecture.  The problem is that I call
> dwarf2_frame_set_init_reg from within the s390_gdbarch_init routine
> (which I gather is the right place?), and at this point in time,
> the gdbarch_data call in dwarf2_frame_set_init_reg returns NULL
> because the gdbarch hasn't finished initialization yet:
> 
> gdbarch_data (struct gdbarch *gdbarch, struct gdbarch_data *data)
> {
>   gdb_assert (data->index < gdbarch->nr_data);
>   /* The data-pointer isn't initialized, call init() to get a value but
>      only if the architecture initializaiton has completed.  Otherwise
>      punt - hope that the caller knows what they are doing.  */
>   if (gdbarch->data[data->index] == NULL
>       && gdbarch->initialized_p)

Oopsie.  Yes, now I can see what's going on - I'm not sure what should
change here.  Andrew, do you recall if the initialized_p check was for
any specific problem, or might we be able to remove it?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer