Add page tests to string/test-strnlen.

Submitted by Wainer dos Santos Moschetta on March 8, 2017, 12:48 p.m.

Details

Message ID 20170308124831.11648-1-wainersm@linux.vnet.ibm.com
State New
Headers show

Commit Message

Wainer dos Santos Moschetta March 8, 2017, 12:48 p.m.
May be tricky for implementations to handle strings around
page boundary once, for instance, it is performed unaligned loads or
when maxlen is used as a hint for vectorized loops. The test cases
should unveil regression bugs on these cases.

To some extend do_random_tests in string/test-strnlen tests strings
placed at page end but it does not cover all cases. So this change
adds tests which consists of placing strings of varying sizes ending
at the page boundary. It also combines with different values of maxlen.

Tested on ppc64le and x86_64.

2017-03-08  Wainer dos Santos Moschetta  <wainersm@linux.vnet.ibm.com>

	* string/test-strnlen.c (do_page_tests): New function
	to check length of strings ending at the page boundary.
	(test_main): Added call to the do_page_tests function.
---
 string/test-strnlen.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

Patch hide | download patch | download mbox

diff --git a/string/test-strnlen.c b/string/test-strnlen.c
index 7059669..4a6fdd3 100644
--- a/string/test-strnlen.c
+++ b/string/test-strnlen.c
@@ -143,6 +143,56 @@  do_random_tests (void)
     }
 }
 
+/* Tests meant to unveil fail on implementation that does not access bytes
+   around the page boundary accordingly.  */
+static void
+do_page_tests (void)
+{
+  size_t i, exp_len, offset;
+  /* Calculate the null character offset.  */
+  size_t last_offset = (page_size / sizeof (CHAR)) - 1;
+
+  CHAR *s = (CHAR *) buf1;
+  for (i = 0; i < last_offset; i++)
+    s[i] = (random() & 127) + 1;
+  s[i] = 0;
+
+  /* Place short strings ending at page boundary.  */
+  offset = last_offset;
+  for (i = 0; i < 128; i++)
+    {
+      offset--;
+      exp_len = last_offset - offset;
+      FOR_EACH_IMPL (impl, 0)
+        {
+          /* Varies maxlen value to cover the cases where it is:
+               - larger than length;
+               - slightly greater than length;
+               - equal to length;
+               - slightly less than length.  */
+          do_one_test (impl, (CHAR *) (s + offset), page_size, exp_len);
+          do_one_test (impl, (CHAR *) (s + offset), exp_len + 1, exp_len);
+          do_one_test (impl, (CHAR *) (s + offset), exp_len, exp_len);
+          if (exp_len > 0)
+            do_one_test (impl, (CHAR *) (s + offset), exp_len - 1, exp_len - 1);
+        }
+    }
+
+  /* Place long strings ending at page boundary.  */
+  offset = (last_offset + 1) / 2;
+  for (i = 0; i < 64; ++i)
+    {
+      offset += i;
+      if (offset >= (last_offset + 1))
+        break;
+      exp_len = last_offset - offset;
+      FOR_EACH_IMPL (impl, 0)
+          /* Checks only for maxlen larger than length because other cases are
+             already covered in do_random_tests.  */
+          do_one_test (impl, (CHAR *) (s + offset), page_size, exp_len);
+    }
+}
+
 int
 test_main (void)
 {
@@ -188,6 +238,7 @@  test_main (void)
     }
 
   do_random_tests ();
+  do_page_tests ();
   return ret;
 }