calls: Fix a memory leak in maybe_warn_rdwr_sizes [PR99004]

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.

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.

diff --git a/gcc/calls.c b/gcc/calls.c
index 354adc606c2f2133fff4767e2c4f0e909eb37b9a..1fea022ad8af799b3456bf6376bc55a6a78beeb0 100644 (file)
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -2032,7 +2032,7 @@ maybe_warn_rdwr_sizes (rdwr_map *rwm, tree fndecl, tree fntype, tree exp)
       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, tree fndecl, tree fntype, tree exp)
            }
          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';