[PATCH] calls: Fix a memory leak in maybe_warn_rdwr_sizes [PR99004]

[Jakub Jelinek]

Hi!

The print_generic_expr_to_str function ends with
return xstrdup (...); and therefore expects the caller to free
the argument.

The following patch does that after it has been copied.
Instead of doing const_cast to cast away const char * to char *,
because the code uses s0 and s1 in so few places, I chose just
to change the types of the two variables so that const_cast
is not needed.  After all, it is a heap allocated string that
this function owns and so if it wanted, it could change it too.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2021-02-09  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/99004
	* calls.c (maybe_warn_rdwr_sizes): Change s0 and s1 type from
	const char * to char * and free those pointers after use.

--- gcc/calls.c.jj	2021-01-04 10:25:39.253229068 +0100
+++ gcc/calls.c	2021-02-08 17:39:10.749551785 +0100
@@ -2032,7 +2032,7 @@ maybe_warn_rdwr_sizes (rdwr_map *rwm, tr
       tree sizrng[2] = { size_zero_node, build_all_ones_cst (sizetype) };
       if (get_size_range (access_size, sizrng, true))
 	{
-	  const char *s0 = print_generic_expr_to_str (sizrng[0]);
+	  char *s0 = print_generic_expr_to_str (sizrng[0]);
 	  if (tree_int_cst_equal (sizrng[0], sizrng[1]))
 	    {
 	      gcc_checking_assert (strlen (s0) < sizeof sizstr);
@@ -2040,11 +2040,13 @@ maybe_warn_rdwr_sizes (rdwr_map *rwm, tr
 	    }
 	  else
 	    {
-	      const char *s1 = print_generic_expr_to_str (sizrng[1]);
+	      char *s1 = print_generic_expr_to_str (sizrng[1]);
 	      gcc_checking_assert (strlen (s0) + strlen (s1)
 				   < sizeof sizstr - 4);
 	      sprintf (sizstr, "[%s, %s]", s0, s1);
+	      free (s1);
 	    }
+	  free (s0);
 	}
       else
 	*sizstr = '\0';

	Jakub