Macro definitions in AST files have their own IDs.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114014 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 3714b77..8628d74 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -112,10 +112,13 @@
     typedef llvm::DenseMap<QualType, TypeIdx, UnsafeQualTypeDenseMapInfo>
         TypeIdxMap;
 
-    /// \brief An ID number that refers to an identifier in an AST
-    /// file.
+    /// \brief An ID number that refers to an identifier in an AST file.
     typedef uint32_t IdentID;
 
+    /// \brief An ID number that refers to a macro in an AST file.
+    typedef uint32_t MacroID;
+
+    /// \brief An ID number that refers to an ObjC selctor in an AST file.
     typedef uint32_t SelectorID;
 
     /// \brief Describes the various kinds of blocks that occur within