[PATCH] genrecog: Fix crash on invalid input

[PATCH] genrecog: Fix crash on invalid input

[Segher Boessenkool]

If your machine description refers to a non-existent predicate genrecog
crashes.  This fixes it.

Is this okay for trunk?


Segher


2016-03-14  Segher Boeesenkool  <segher#kernel.crashing.org>

	* genrecog.c (safe_predicate_mode): If PRED is NULL, return false.

---
 gcc/genrecog.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gcc/genrecog.c b/gcc/genrecog.c
index f8b8ef4..65882f4 100644
--- a/gcc/genrecog.c
+++ b/gcc/genrecog.c
@@ -3378,6 +3378,9 @@ find_subroutines (routine_type type, state *s, vec <state *> &procs)
 static bool
 safe_predicate_mode (const struct pred_data *pred, machine_mode mode)
 {
+  if (!pred)
+    return false;
+
   /* Scalar integer constants have VOIDmode.  */
   if (GET_MODE_CLASS (mode) == MODE_INT
       && (pred->codes[CONST_INT]
-- 
1.9.3

Re: [PATCH] genrecog: Fix crash on invalid input

[Bernd Schmidt]

On 03/14/2016 04:38 PM, Segher Boessenkool wrote:
> If your machine description refers to a non-existent predicate genrecog
> crashes.  This fixes it.

Might be better to fix the caller?


Bernd

Re: [PATCH] genrecog: Fix crash on invalid input

[Segher Boessenkool]

On Mon, Mar 14, 2016 at 06:39:12PM +0100, Bernd Schmidt wrote:
> On 03/14/2016 04:38 PM, Segher Boessenkool wrote:
> >If your machine description refers to a non-existent predicate genrecog
> >crashes.  This fixes it.
> 
> Might be better to fix the caller?

Yeah maybe.  The next function that takes a pred also tests for !pred,
but let me see what the caller of the failing case is.


Segher

Re: [PATCH] genrecog: Fix crash on invalid input

[Segher Boessenkool]

On Mon, Mar 14, 2016 at 01:41:38PM -0500, Segher Boessenkool wrote:
> On Mon, Mar 14, 2016 at 06:39:12PM +0100, Bernd Schmidt wrote:
> > On 03/14/2016 04:38 PM, Segher Boessenkool wrote:
> > >If your machine description refers to a non-existent predicate genrecog
> > >crashes.  This fixes it.
> > 
> > Might be better to fix the caller?
> 
> Yeah maybe.  The next function that takes a pred also tests for !pred,
> but let me see what the caller of the failing case is.

There is just the single caller, and pred is set right before the call
there.  How about this patch, then?


Segher


Subject: [PATCH] genrecog: Fix crash on invalid input

If your machine description refers to a non-existent predicate genrecog
crashes.  This fixes it.


2016-03-14  Segher Boeesenkool  <segher#kernel.crashing.org>

	* genrecog.c (match_pattern_2): If pred is NULL don't call
	safe_predicate_mode on it.

---
 gcc/genrecog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/genrecog.c b/gcc/genrecog.c
index f8b8ef4..47e4266 100644
--- a/gcc/genrecog.c
+++ b/gcc/genrecog.c
@@ -4037,7 +4037,7 @@ match_pattern_2 (state *s, md_rtx_info *info, position *pos, rtx pattern)
 		/* Check the mode first, to distinguish things like SImode
 		   and DImode register_operands, as described above.  */
 		machine_mode mode = GET_MODE (e->pattern);
-		if (safe_predicate_mode (pred, mode))
+		if (pred && safe_predicate_mode (pred, mode))
 		  s = add_decision (s, rtx_test::mode (e->pos), mode, true);
 
 		/* Assign to operands[] first, so that the rtx usually doesn't
-- 
1.9.3

Re: [PATCH] genrecog: Fix crash on invalid input

[Bernd Schmidt]

On 03/14/2016 09:00 PM, Segher Boessenkool wrote:
> There is just the single caller, and pred is set right before the call
> there.  How about this patch, then?

Looks alright.


Bernd