re PR sanitizer/71480 (ASan should align string constants to shadow granularity.)

2016-06-10  Maxim Ostapenko  <m.ostapenko@samsung.com>

	PR sanitizer/71480
	* varasm.c (place_block_symbol): Adjust alignment for asan protected
	STRING_CSTs even if TREE_CONSTANT_POOL_ADDRESS_P.

	* c-c++-common/asan/pr71480.c: New test.

From-SVN: r237306

gcc/ChangeLog

+2016-06-10  Maxim Ostapenko  <m.ostapenko@samsung.com>
+
+	PR sanitizer/71480
+	* varasm.c (place_block_symbol): Adjust alignment for asan protected
+	STRING_CSTs even if TREE_CONSTANT_POOL_ADDRESS_P.
+
 2016-06-10  Jan Hubicka  <hubicka@ucw.cz>
 
 	* profile.c: Include cfgloop.h.

gcc/testsuite/ChangeLog

+2016-06-10  Maxim Ostapenko  <m.ostapenko@samsung.com>
+
+	PR sanitizer/71480
+	* c-c++-common/asan/pr71480.c: New test.
+
 2016-06-10  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.dg/guality/pr68037-1.c (ASMNAME): New.

gcc/testsuite/c-c++-common/asan/pr71480.c

+/* { dg-do run } */
+
+__attribute__ ((noinline, noclone)) int
+foo (char *c)
+{
+  asm volatile ("" : : "r" (c) : "memory");
+  return 1;
+}
+
+__attribute__ ((noinline, noclone)) void
+bar (char *c)
+{
+  asm volatile ("" : : "r" (c) : "memory");
+}
+
+int main ()
+{
+  char tpl[20] = "/tmp/test.XXXXXX";
+  char tpl2[20] = "/tmp/test.XXXXXX";
+  int fd = foo (tpl);
+  int fd2 = foo (tpl2);
+  if (fd == -1)
+    {
+      if (fd2 != -1)
+	 bar (tpl2);
+      return 1;
+    }
+
+  if (fd2 == -1)
+    return 1;
+
+  bar (tpl);
+  bar (tpl2);
+
+  if (__builtin_strcmp (tpl, "/tmp/test.XXXXXX") != 0)
+    return 1;
+
+  if (__builtin_strcmp (tpl, tpl2) != 0)
+    return 1;
+
+   return 0;
+}

gcc/varasm.c

@@ -7201,7 +7201,11 @@ place_block_symbol (rtx symbol)
       if ((flag_sanitize & SANITIZE_ADDRESS)
 	  && TREE_CODE (DECL_INITIAL (decl)) == STRING_CST
 	  && asan_protect_global (DECL_INITIAL (decl)))
-	size += asan_red_zone_size (size);
+	{
+	  size += asan_red_zone_size (size);
+	  alignment = MAX (alignment,
+			   ASAN_RED_ZONE_SIZE * BITS_PER_UNIT);
+	}
     }
   else
     {