From: Dominik Vogt <vogt@linux.vnet.ibm.com>
To: Bernd Schmidt <bschmidt@redhat.com>, Jeff Law <law@redhat.com>,
gcc-patches@gcc.gnu.org,
Andreas Krebbel <krebbel@linux.vnet.ibm.com>,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
Andreas Arnez <arnez@linux.vnet.ibm.com>
Subject: Re: [PATCH v5] Allocate constant size dynamic stack space in the prologue
Date: Mon, 11 Jul 2016 11:44:00 -0000 [thread overview]
Message-ID: <20160711114412.GA6171@linux.vnet.ibm.com> (raw)
In-Reply-To: <20160707115716.GA14409@linux.vnet.ibm.com>
On Thu, Jul 07, 2016 at 12:57:16PM +0100, Dominik Vogt wrote:
> On Wed, Jul 06, 2016 at 02:01:06PM +0200, Bernd Schmidt wrote:
> > There's one thing I don't quite understand and which seems to have
> > changed since v1:
> >
> > On 07/04/2016 02:19 PM, Dominik Vogt wrote:
> > >@@ -1099,8 +1101,10 @@ expand_stack_vars (bool (*pred) (size_t), struct stack_vars_data *data)
> > >
> > > /* If there were any, allocate space. */
> > > if (large_size > 0)
> > >- large_base = allocate_dynamic_stack_space (GEN_INT (large_size), 0,
> > >- large_align, true);
> > >+ {
> > >+ large_allocsize = GEN_INT (large_size);
> > >+ get_dynamic_stack_size (&large_allocsize, 0, large_align, NULL);
> > >+ }
> > > }
> > >
> > > for (si = 0; si < n; ++si)
> > >@@ -1186,6 +1190,19 @@ expand_stack_vars (bool (*pred) (size_t), struct stack_vars_data *data)
> > > /* Large alignment is only processed in the last pass. */
> > > if (pred)
> > > continue;
> > >+
> > >+ if (large_allocsize && ! large_allocation_done)
> > >+ {
> > >+ /* Allocate space the virtual stack vars area in the
> > >+ prologue. */
> > >+ HOST_WIDE_INT loffset;
> > >+
> > >+ loffset = alloc_stack_frame_space
> > >+ (INTVAL (large_allocsize),
> > >+ PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT);
> > >+ large_base = get_dynamic_stack_base (loffset, large_align);
> > >+ large_allocation_done = true;
> > >+ }
> > > gcc_assert (large_base != NULL);
> > >
> >
> > Why is this code split between the two places here?
>
> This is a bugfix from v1 to v2.
> I think I had to move this code to the second loop so that the
> space for dynamically aligned variables is allocated at the "end"
> of the space for stack variables. I cannot remember what the bug
> was, but maybe it was that the variables with fixed and static
> alignment ended up at the same address.
>
> Anyway, now that the new allocation strategy is used
> unconditionally, it should be possible to move the
> get_dynamic_stack_size call down to the second loop and simplify
> the code somewhat. I'll look into that.
Version 5 with some code moved from the first loop to the second.
Ciao
Dominik ^_^ ^_^
--
Dominik Vogt
IBM Germany
next prev parent reply other threads:[~2016-07-11 11:44 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 13:17 [PATCH] " Dominik Vogt
2015-11-25 13:33 ` Bernd Schmidt
2015-11-25 14:54 ` Dominik Vogt
2015-11-25 15:06 ` Bernd Schmidt
2015-11-27 14:13 ` Dominik Vogt
2015-11-27 14:24 ` Dominik Vogt
2015-12-02 19:05 ` Jeff Law
2015-12-03 0:16 ` Bernd Schmidt
2016-05-06 9:38 ` [PATCH v2] " Dominik Vogt
2016-05-06 9:44 ` Dominik Vogt
2016-06-20 11:09 ` [PATCH v2, PING 1] " Dominik Vogt
2016-06-23 4:46 ` [PATCH v2] " Jeff Law
2016-06-23 15:48 ` Dominik Vogt
2016-06-24 12:40 ` Dominik Vogt
2016-07-04 12:20 ` Dominik Vogt
2016-07-04 14:09 ` Andreas Krebbel
2016-07-06 12:01 ` Bernd Schmidt
2016-07-07 11:57 ` Dominik Vogt
2016-07-11 11:44 ` Dominik Vogt [this message]
2016-07-13 22:12 ` [PATCH v5] " Jeff Law
2016-07-14 9:11 ` Dominik Vogt
2016-07-15 11:51 ` Bernd Schmidt
2016-07-15 12:05 ` Dominik Vogt
2016-07-15 12:22 ` Dominik Vogt
2016-07-15 13:18 ` Bernd Schmidt
2016-07-18 13:11 ` Andreas Krebbel
2016-06-23 4:43 ` [PATCH v2] " Jeff Law
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