diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index 218b37707d52ac20e5077032d58835134b83922a..37072a765824427fc22937aa9aa0d5a7f3757be7 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -2377,6 +2377,38 @@ CINDEX_LINKAGE enum CXLanguageKind clang_getCursorLanguage(CXCursor cursor);
  */
 CINDEX_LINKAGE CXTranslationUnit clang_Cursor_getTranslationUnit(CXCursor);
 
+
+/**
+ * \brief A fast container representing a set of CXCursors.
+ */
+typedef struct CXCursorSetImpl *CXCursorSet;
+
+/**
+ * \brief Creates an empty CXCursorSet.
+ */
+CINDEX_LINKAGE CXCursorSet clang_createCXCursorSet(void);
+
+/**
+ * \brief Disposes a CXCursorSet and releases its associated memory.
+ */
+CINDEX_LINKAGE void clang_disposeCXCursorSet(CXCursorSet cset);
+
+/**
+ * \brief Queries a CXCursorSet to see if it contains a specific CXCursor.
+ *
+ * \returns non-zero if the set contains the specified cursor.
+*/
+CINDEX_LINKAGE unsigned clang_CXCursorSet_contains(CXCursorSet cset,
+                                                   CXCursor cursor);
+
+/**
+ * \brief Inserts a CXCursor into a CXCursorSet.
+ *
+ * \returns zero if the CXCursor was already in the set, and non-zero otherwise.
+*/
+CINDEX_LINKAGE unsigned clang_CXCursorSet_insert(CXCursorSet cset,
+                                                 CXCursor cursor);
+
 /**
  * \brief Determine the semantic parent of the given cursor.
  *
diff --git a/tools/libclang/CXCursor.cpp b/tools/libclang/CXCursor.cpp
index f494d96be4c8c7ed1a24f12d40553137f6460286..b5682055b9e3851c7af918e2eae6e62c081575ad 100644
--- a/tools/libclang/CXCursor.cpp
+++ b/tools/libclang/CXCursor.cpp
@@ -997,6 +997,72 @@ CXCursor clang_Cursor_getArgument(CXCursor C, unsigned i) {
   return clang_getNullCursor();
 }
 
+} // end: extern "C"
+
+//===----------------------------------------------------------------------===//
+// CXCursorSet.
+//===----------------------------------------------------------------------===//
+
+typedef llvm::DenseMap<CXCursor, unsigned> CXCursorSet_Impl;
+
+static inline CXCursorSet packCXCursorSet(CXCursorSet_Impl *setImpl) {
+  return (CXCursorSet) setImpl;
+}
+static inline CXCursorSet_Impl *unpackCXCursorSet(CXCursorSet set) {
+  return (CXCursorSet_Impl*) set;
+}
+namespace llvm {
+template<> struct DenseMapInfo<CXCursor> {
+public:
+  static inline CXCursor getEmptyKey() {
+    return MakeCXCursorInvalid(CXCursor_InvalidFile);
+  }
+  static inline CXCursor getTombstoneKey() {
+    return MakeCXCursorInvalid(CXCursor_NoDeclFound);
+  }
+  static inline unsigned getHashValue(const CXCursor &cursor) {
+    return llvm::DenseMapInfo<std::pair<const void *, const void *> >
+      ::getHashValue(std::make_pair(cursor.data[0], cursor.data[1]));
+  }
+  static inline bool isEqual(const CXCursor &x, const CXCursor &y) {
+    return x.kind == y.kind &&
+           x.data[0] == y.data[0] &&
+           x.data[1] == y.data[1];
+  }
+};
+}
+
+extern "C" {
+CXCursorSet clang_createCXCursorSet() {
+  return packCXCursorSet(new CXCursorSet_Impl());
+}
+
+void clang_disposeCXCursorSet(CXCursorSet set) {
+  delete unpackCXCursorSet(set);
+}
+
+unsigned clang_CXCursorSet_contains(CXCursorSet set, CXCursor cursor) {
+  CXCursorSet_Impl *setImpl = unpackCXCursorSet(set);
+  if (!setImpl)
+    return 0;
+  return setImpl->find(cursor) == setImpl->end();
+}
+
+unsigned clang_CXCursorSet_insert(CXCursorSet set, CXCursor cursor) {
+  // Do not insert invalid cursors into the set.
+  if (cursor.kind >= CXCursor_FirstInvalid &&
+      cursor.kind <= CXCursor_LastInvalid)
+    return 1;
+
+  CXCursorSet_Impl *setImpl = unpackCXCursorSet(set);
+  if (!setImpl)
+    return 1;
+  unsigned &entry = (*setImpl)[cursor];
+  unsigned flag = entry == 0 ? 1 : 0;
+  entry = 1;
+  return flag;
+}
+  
 CXCompletionString clang_getCursorCompletionString(CXCursor cursor) {
   enum CXCursorKind kind = clang_getCursorKind(cursor);
   if (clang_isDeclaration(kind)) {
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index 3fe8378a8b2f478a2233970a7e22d076e08fe25b..c7508bc5449becee2348bd9cb64665cd12b4c578 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -1,3 +1,5 @@
+clang_CXCursorSet_contains
+clang_CXCursorSet_insert
 clang_CXIndex_getGlobalOptions
 clang_CXIndex_setGlobalOptions
 clang_CXXMethod_isStatic
@@ -77,6 +79,7 @@ clang_constructUSR_ObjCIvar
 clang_constructUSR_ObjCMethod
 clang_constructUSR_ObjCProperty
 clang_constructUSR_ObjCProtocol
+clang_createCXCursorSet
 clang_createIndex
 clang_createTranslationUnit
 clang_createTranslationUnitFromSourceFile
@@ -85,6 +88,7 @@ clang_defaultDiagnosticDisplayOptions
 clang_defaultEditingTranslationUnitOptions
 clang_defaultReparseOptions
 clang_defaultSaveOptions
+clang_disposeCXCursorSet
 clang_disposeCXTUResourceUsage
 clang_disposeCodeCompleteResults
 clang_disposeDiagnostic