1 files changed, 7 insertions, 0 deletions
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 18b106ad84..27c2e676e6 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -476,6 +476,13 @@ static void InitializePredefinedMacros(Preprocessor &PP,
     DefineBuiltinMacro(Buf, "__int64=long long");
     DefineBuiltinMacro(Buf, "__declspec(X)=");
   }
+  if (PP.getLangOptions().Blocks) {
+    DefineBuiltinMacro(Buf, "__byref=__attribute__((__blocks__(byref)))");
+    DefineBuiltinMacro(Buf, "__block=__attribute__((__blocks__(byref)))");
+  } else {
+    DefineBuiltinMacro(Buf, "__byref=");
+    DefineBuiltinMacro(Buf, "__block=");
+  }
   // FIXME: Should emit a #line directive here.
 }