Don't warn about null characters in Objective-C format string literals.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127703 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index ea14b4b..24cf23b 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -1218,10 +1218,12 @@
 }
 
 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
-  // The presence of a null character is likely an error.
-  S.Diag(getLocationOfByte(nullCharacter),
-         diag::warn_printf_format_string_contains_null_char)
-    << getFormatStringRange();
+  if (!IsObjCLiteral) {
+    // The presence of a null character is likely an error.
+    S.Diag(getLocationOfByte(nullCharacter),
+           diag::warn_printf_format_string_contains_null_char)
+      << getFormatStringRange();
+  }
 }
 
 const Expr *CheckFormatHandler::getDataArg(unsigned i) const {