On Mon, Apr 8, 2024 at 6:29 PM Richard Biener <rguent...@suse.de> wrote: > > > > > Am 08.04.2024 um 18:09 schrieb Aldy Hernandez <al...@redhat.com>: > > > > On Mon, Apr 8, 2024 at 5:54 PM Jakub Jelinek <ja...@redhat.com> wrote: > >> > >> On Mon, Apr 08, 2024 at 05:40:23PM +0200, Aldy Hernandez wrote: > >>>> PR middle-end/114604 > >>>> * gimple-range.cc (enable_ranger): Initialize the global > >>>> bitmap obstack. > >>>> (disable_ranger): Release it. > >>>> --- > >>>> gcc/gimple-range.cc | 4 ++++ > >>>> 1 file changed, 4 insertions(+) > >>>> > >>>> diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc > >>>> index c16b776c1e3..4d3b1ce8588 100644 > >>>> --- a/gcc/gimple-range.cc > >>>> +++ b/gcc/gimple-range.cc > >>>> @@ -689,6 +689,8 @@ enable_ranger (struct function *fun, bool > >>>> use_imm_uses) > >>>> { > >>>> gimple_ranger *r; > >>>> > >>>> + bitmap_obstack_initialize (NULL); > >>>> + > >>>> gcc_checking_assert (!fun->x_range_query); > >>>> r = new gimple_ranger (use_imm_uses); > >>>> fun->x_range_query = r; > >>>> @@ -705,6 +707,8 @@ disable_ranger (struct function *fun) > >>>> gcc_checking_assert (fun->x_range_query); > >>>> delete fun->x_range_query; > >>>> fun->x_range_query = NULL; > >>>> + > >>>> + bitmap_obstack_release (NULL); > >>> > >>> Are you not allowed to initialize/use obstacks unless > >>> bitmap_obstack_initialize(NULL) is called? > >> > >> You can use it with some other obstack, just not the default one. > >> > >>> If so, wouldn't it be > >>> better to lazily initialize it downstream (bitmap_alloc, or whomever > >>> needs it initialized)? > >> > >> No, you still need to decide where is the safe point to release it. > >> Unlike the non-default bitmap_obstack_initialize/bitmap_obstack_release, > >> the default one can nest (has associated nesting counter). So, the above > >> patch just says that ranger starts using the default obstack in > >> enable_ranger and stops using it in disable_ranger and anything ranger > >> associated in the obstack can be freed at that point. > > > > I thought ranger never used the default one: > > > > $ grep bitmap_obstack_initialize *value* *range* > > value-relation.cc: bitmap_obstack_initialize (&m_bitmaps); > > value-relation.cc: bitmap_obstack_initialize (&m_bitmaps); > > gimple-range-cache.cc: bitmap_obstack_initialize (&m_bitmaps); > > gimple-range-gori.cc: bitmap_obstack_initialize (&m_bitmaps); > > gimple-range-infer.cc: bitmap_obstack_initialize (&m_bitmaps); > > gimple-range-phi.cc: bitmap_obstack_initialize (&m_bitmaps); > > > > or even: > > > > $ grep obstack.*NULL *value* *range* > > value-range-storage.cc: obstack_free (&m_obstack, NULL); > > value-relation.cc: obstack_free (&m_chain_obstack, NULL); > > value-relation.cc: obstack_free (&m_chain_obstack, NULL); > > gimple-range-infer.cc: obstack_free (&m_list_obstack, NULL); > > value-range-storage.cc: obstack_free (&m_obstack, NULL); > > > > I'm obviously missing something here. > > Look for BITMAP_ALLOC (NULL) in the backtrace in the PR
Ahh! Thanks. A few default obstack uses snuck in while I wasn't looking. $ grep BITMAP_ALLOC.*NULL *range* gimple-range-cache.cc: m_propfail = BITMAP_ALLOC (NULL); gimple-range-cache.h: inline ssa_lazy_cache () { active_p = BITMAP_ALLOC (NULL); } gimple-range.cc: m_pop_list = BITMAP_ALLOC (NULL); I wonder if it would be cleaner to just change these to use named obstacks. Andrew, is there a reason we were using the default obstack for these? For reference, they are class update_list used in the ranger cache, ssa_lazy_cache, and dom_ranger. Aldy