From: Aldy Hernandez <aldyh@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Richard Biener <rguenther@suse.de>,
gcc-patches@gcc.gnu.org, amacleod@redhat.com
Subject: Re: [PATCH] middle-end/114604 - ranger allocates bitmap without initialized obstack
Date: Mon, 8 Apr 2024 18:08:37 +0200 [thread overview]
Message-ID: <CAGm3qMWm3aUXE_oSr_PfMhei8gqxSk5KkSHigBH+5fwyAJfsuw@mail.gmail.com> (raw)
In-Reply-To: <ZhQTOb2RGLQ+ChDl@tucnak>
On Mon, Apr 8, 2024 at 5:54 PM Jakub Jelinek <jakub@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.
Aldy
next prev parent reply other threads:[~2024-04-08 16:08 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240408095018.4853D385841E@sourceware.org>
2024-04-08 15:40 ` Aldy Hernandez
2024-04-08 15:54 ` Jakub Jelinek
2024-04-08 16:08 ` Aldy Hernandez [this message]
2024-04-08 16:28 ` Richard Biener
2024-04-08 16:39 ` Aldy Hernandez
2024-04-08 17:47 ` Richard Biener
2024-04-09 5:43 ` Aldy Hernandez
2024-04-09 6:48 ` Richard Biener
2024-06-20 8:08 ` Aldy Hernandez
2024-06-20 9:31 ` Richard Biener
2024-06-20 14:05 ` Andrew MacLeod
2024-06-20 14:36 ` Richard Biener
2024-06-26 8:50 ` Aldy Hernandez
2024-04-08 9:49 Richard Biener
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