1 files changed, 11 insertions, 0 deletions
diff --git a/clang/include/clang/Basic/IdentifierTable.h b/clang/include/clang/Basic/IdentifierTable.h
index 7aa1d074a59..ea5d7adeb2d 100644
--- a/clang/include/clang/Basic/IdentifierTable.h
+++ b/clang/include/clang/Basic/IdentifierTable.h
@@ -384,6 +384,17 @@ public:
     return getName().startswith("<#") && getName().endswith("#>");
   }
 
+  /// Determine whether \p this is a name reserved for the implementation (C99
+  /// 7.1.3, C++ [lib.global.names]).
+  bool isReservedName(bool doubleUnderscoreOnly = false) const {
+    if (getLength() < 2)
+      return false;
+    const char *Name = getNameStart();
+    return Name[0] == '_' &&
+           (Name[1] == '_' ||
+            (Name[1] >= 'A' && Name[1] <= 'Z' && !doubleUnderscoreOnly));
+  }
+
   /// Provide less than operator for lexicographical sorting.
   bool operator<(const IdentifierInfo &RHS) const {
     return getName() < RHS.getName();