diff mbox

Fix PR66206

Message ID 56735A98.9010601@t-online.de
State New
Headers show

Commit Message

Bernd Schmidt Dec. 18, 2015, 1 a.m. UTC 
This is a small problem found by a static analyzer, a function in 
bt-load can in theory return the address of a local variable.

Bootstrapped and tested on x86_64-linux, ok?


Bernd

Comments

Andrew Pinski Dec. 18, 2015, 1:15 a.m. UTC | #1 
On Thu, Dec 17, 2015 at 5:00 PM, Bernd Schmidt <bernds_cb1@t-online.de> wrote:
> This is a small problem found by a static analyzer, a function in bt-load
> can in theory return the address of a local variable.
>
> Bootstrapped and tested on x86_64-linux, ok?

Except PATTERN (insn) will never be a REG.
The only case where the input can be a REG is:
gcc_assert (!find_btr_use (src));

And that is basically making sure the left hand side is not part of
all_btrs so the way to fix that would be simpler if you define a new
function called btr_use_p or something to that effect and return
true/false instead.

Also if you are touching this code, can you change the literal 0 to
NULL inside find_btr_use.

Thanks,
Andrew





>
>
> Bernd
Bernd Schmidt Dec. 18, 2015, 1:21 a.m. UTC | #2 
On 12/18/2015 02:15 AM, Andrew Pinski wrote:
>
> Except PATTERN (insn) will never be a REG.
> The only case where the input can be a REG is:
> gcc_assert (!find_btr_use (src));

Yeah, so we _are_ calling it with a REG. It's a minor issue that won't 
trigger in practice, but in order to close the PR we might as well fix 
it and this is the least invasive way.


Bernd
Eric Botcazou Dec. 19, 2015, 10:11 a.m. UTC | #3 
> This is a small problem found by a static analyzer, a function in
> bt-load can in theory return the address of a local variable.
> 
> Bootstrapped and tested on x86_64-linux, ok?

OK, thanks.
Jeff Law Dec. 21, 2015, 8:08 p.m. UTC | #4 
On 12/17/2015 06:00 PM, Bernd Schmidt wrote:
> This is a small problem found by a static analyzer, a function in
> bt-load can in theory return the address of a local variable.
>
> Bootstrapped and tested on x86_64-linux, ok?
OK.

jeff
diff mbox

Patch

	PR rtl-optimization/66206
	* bt-load.c (find_btr_use): Change first arg to be a pointer to an rtx.
	All callers changed.

Index: gcc/bt-load.c
===================================================================
--- gcc/bt-load.c	(revision 231653)
+++ gcc/bt-load.c	(working copy)
@@ -1,4 +1,3 @@ 
-
 /* Perform branch target register load optimizations.
    Copyright (C) 2001-2015 Free Software Foundation, Inc.
 
@@ -188,14 +187,14 @@  basic_block_freq (const_basic_block bb)
   return bb->frequency;
 }
 
-/* If X references (sets or reads) any branch target register, return one
-   such register.  If EXCLUDEP is set, disregard any references within
-   that location.  */
+/* If the rtx at *XP references (sets or reads) any branch target
+   register, return one such register.  If EXCLUDEP is set, disregard
+   any references within that location.  */
 static rtx *
-find_btr_use (rtx x, rtx *excludep = 0)
+find_btr_use (rtx *xp, rtx *excludep = 0)
 {
   subrtx_ptr_iterator::array_type array;
-  FOR_EACH_SUBRTX_PTR (iter, array, &x, NONCONST)
+  FOR_EACH_SUBRTX_PTR (iter, array, xp, NONCONST)
     {
       rtx *loc = *iter;
       if (loc == excludep)
@@ -232,7 +231,7 @@  insn_sets_btr_p (const rtx_insn *insn, i
       if (REG_P (dest)
 	  && TEST_HARD_REG_BIT (all_btrs, REGNO (dest)))
 	{
-	  gcc_assert (!find_btr_use (src));
+	  gcc_assert (!find_btr_use (&src));
 
 	  if (!check_const || CONSTANT_P (src))
 	    {
@@ -324,7 +323,7 @@  new_btr_user (basic_block bb, int insn_l
      to decide whether we can replace all target register
      uses easily.
    */
-  rtx *usep = find_btr_use (PATTERN (insn));
+  rtx *usep = find_btr_use (&PATTERN (insn));
   rtx use;
   btr_user *user = NULL;
 
@@ -335,7 +334,7 @@  new_btr_user (basic_block bb, int insn_l
       /* We want to ensure that USE is the only use of a target
 	 register in INSN, so that we know that to rewrite INSN to use
 	 a different target register, all we have to do is replace USE.  */
-      unambiguous_single_use = !find_btr_use (PATTERN (insn), usep);
+      unambiguous_single_use = !find_btr_use (&PATTERN (insn), usep);
       if (!unambiguous_single_use)
 	usep = NULL;
     }
@@ -511,7 +510,7 @@  compute_defs_uses_and_gen (btr_heap_t *a
 		}
 	      else
 		{
-		  if (find_btr_use (PATTERN (insn)))
+		  if (find_btr_use (&PATTERN (insn)))
 		    {
 		      btr_user *user = new_btr_user (bb, insn_luid, insn);