Add initial support for constant CFStrings.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@41136 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/cfstring.c b/test/Sema/cfstring.c
new file mode 100644
index 0000000..41181ea
--- /dev/null
+++ b/test/Sema/cfstring.c
@@ -0,0 +1,10 @@
+#define CFSTR __builtin___CFStringMakeConstantString
+
+// RUN: clang %s -parse-ast-check
+void f() {
+  CFSTR("\242"); // expected-warning { CFString literal contains non-ASCII character }
+  CFSTR("\0"); // expected-warning { CFString literal contains NUL character }
+  CFSTR(242); // expected-error { error: CFString literal is not a string constant } \
+  expected-warning { incompatible types }
+  CFSTR("foo", "bar"); // expected-error { error: too many arguments to function }
+}