Re: [PATCH, Pointer Bounds Checker 13/x] Early versioning

[Jeff Law <law at redhat dot com>]

On 06/03/14 03:29, Richard Biener wrote:
> On Tue, Jun 3, 2014 at 7:55 AM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
> > 2014-06-02 21:27 GMT+04:00 Jeff Law <law@redhat.com>:
> > > On 06/02/14 04:48, Ilya Enkovich wrote:
> > > > > Hmm, so if I understand things correctly, src_fun has no loop
> > > > > structures attached, thus there's nothing to copy.  Presumably at
> > > > > some later point we build loop structures for the copy from scratch?
> > > >
> > > > I suppose it is just a simple bug with absent NULL pointer check.  Here is
> > > > original code:
> > > >
> > > >     /* Duplicate the loop tree, if available and wanted.  */
> > > >     if (loops_for_fn (src_cfun) != NULL
> > > >         && current_loops != NULL)
> > > >       {
> > > >         copy_loops (id, entry_block_map->loop_father,
> > > >                     get_loop (src_cfun, 0));
> > > >         /* Defer to cfgcleanup to update loop-father fields of
> > > > basic-blocks.  */
> > > >         loops_state_set (LOOPS_NEED_FIXUP);
> > > >       }
> > > >
> > > >     /* If the loop tree in the source function needed fixup, mark the
> > > >        destination loop tree for fixup, too.  */
> > > >     if (loops_for_fn (src_cfun)->state & LOOPS_NEED_FIXUP)
> > > >       loops_state_set (LOOPS_NEED_FIXUP);
> > > >
> > > > As you may see we have check for absent loops structure in the first
> > > > if-statement and no check in the second one.  I hit segfault and added the
> > > > check.
> > >
> > > Downthread you indicated you're not in SSA form which might explain the
> > > inconsistency here.  If so, then we need to make sure that the loop & df
> > > structures do get set up properly later.
> >
> > That is what init_data_structures pass will do for us as Richard pointed. Right?
>
> loops are set up during the CFG construction and thus are available everywhere.
Which would argue that the hunk that checks for the loop tree's 
existence before accessing it should not be needed.  Ilya -- is it 
possible you hit this prior to Richi's work to build the loop structures 
as part of CFG construction and maintain them throughout compilation.


> the df structures are set up in init_data_structures pass which is run before
> going into SSA form (I'd like to somehow cleanup that area).
OK.   So this part should be approved since we've established this code 
is running prior to going into SSA form.

jeff