diff --git a/src/profile-generator.cc b/src/profile-generator.cc
index 2d0984e..0dc162d 100644
--- a/src/profile-generator.cc
+++ b/src/profile-generator.cc
@@ -3559,9 +3559,9 @@
   // The first (zero) item of nodes array is an object describing node
   // serialization layout.  We use a set of macros to improve
   // readability.
-#define JSON_A(s) "["s"]"
-#define JSON_O(s) "{"s"}"
-#define JSON_S(s) "\""s"\""
+#define JSON_A(s) "[" s "]"
+#define JSON_O(s) "{" s "}"
+#define JSON_S(s) "\"" s "\""
   writer_->AddString(JSON_O(
     JSON_S("fields") ":" JSON_A(
         JSON_S("type")