Index: include/clang/Sema/AttributeList.h
===================================================================
--- include/clang/Sema/AttributeList.h
+++ include/clang/Sema/AttributeList.h
@@ -88,6 +88,8 @@
 struct ParsedAttrInfo {
   /// Which spelling of the attribute this ParsedAttrInfo corresponds to
   unsigned SpellingListIndex;
+  /// Corresponds to the Spelling enum of the corresponding Attr class
+  unsigned SemanticSpelling;
   /// Corresponds to the AttributeList::Kind enum
   unsigned AttrKind : 16;
   /// Corresponds to the AttributeList::Syntax enum
@@ -117,9 +119,9 @@
   unsigned IsLateParsed : 1;
 
   ParsedAttrInfo()
-  : SpellingListIndex(0), AttrKind(0), Syntax(0), NumArgs(0), OptArgs(0),
-    HasCustomParsing(0), IsTargetSpecific(0), IsType(0), IsStmt(0),
-    IsKnownToGCC(0), IsUnevaluatedArgContext(0), IsIdentifierArg(0),
+  : SpellingListIndex(0), SemanticSpelling(0), AttrKind(0), Syntax(0),
+    NumArgs(0), OptArgs(0), HasCustomParsing(0), IsTargetSpecific(0), IsType(0),
+    IsStmt(0), IsKnownToGCC(0), IsUnevaluatedArgContext(0), IsIdentifierArg(0),
     IsTypeArg(0), IsLateParsed(0) { }
 
   virtual ~ParsedAttrInfo() {}
@@ -138,11 +140,6 @@
   virtual bool existsInTarget(const TargetInfo &Target) const {
     return true;
   }
-  /// Convert the spelling index of Attr to a semantic spelling enum value
-  virtual unsigned
-  spellingIndexToSemanticSpelling(const AttributeList &Attr) const {
-    return UINT_MAX;
-  }
 };
 
 /// AttributeList - Represents a syntactic attribute.
Index: lib/Sema/AttributeList.cpp
===================================================================
--- lib/Sema/AttributeList.cpp
+++ lib/Sema/AttributeList.cpp
@@ -207,7 +207,7 @@
 }
 
 unsigned AttributeList::getSemanticSpelling() const {
-  return getInfo()->spellingIndexToSemanticSpelling(*this);
+  return getInfo()->SemanticSpelling;
 }
 
 bool AttributeList::hasVariadicArg() const {
Index: utils/TableGen/ClangAttrEmitter.cpp
===================================================================
--- utils/TableGen/ClangAttrEmitter.cpp
+++ utils/TableGen/ClangAttrEmitter.cpp
@@ -2712,32 +2712,6 @@
   OS << "  }\n\n";
 }
 
-static void GenerateSpellingIndexToSemanticSpelling(const Record &Attr,
-                                                    raw_ostream &OS) {
-  // If the attribute does not have a semantic form, we can bail out early.
-  if (!Attr.getValueAsBit("ASTNode"))
-    return;
-
-  std::vector<FlattenedSpelling> Spellings = GetFlattenedSpellings(Attr);
-
-  // If there are zero or one spellings, or all of the spellings share the same
-  // name, we can also bail out early.
-  if (Spellings.size() <= 1 || SpellingNamesAreCommon(Spellings))
-    return;
-
-  // Generate the enumeration we will use for the mapping.
-  SemanticSpellingMap SemanticToSyntacticMap;
-  std::string Enum = CreateSemanticSpellings(Spellings, SemanticToSyntacticMap);
-  std::string Name = Attr.getName().str() + "AttrSpellingMap";
-
-  OS << "  virtual unsigned spellingIndexToSemanticSpelling(";
-  OS << "const AttributeList &Attr) const {\n";
-  OS << Enum;
-  OS << "    unsigned Idx = Attr.getAttributeSpellingListIndex();\n";
-  WriteSemanticSpellingSwitch("Idx", SemanticToSyntacticMap, OS);
-  OS << "  }\n\n";
-}
-
 static bool IsKnownToGCC(const Record &Attr) {
   // Look at the spellings for this subject; if there are any spellings which
   // claim to be known to GCC, the attribute is known to GCC.
@@ -2765,6 +2739,8 @@
     const Record &Attr = *I.second;
     const std::string &AttrName = I.first;
     std::vector<FlattenedSpelling> Spellings = GetFlattenedSpellings(Attr);
+    SemanticSpellingMap SemanticToSyntacticMap;
+    CreateSemanticSpellings(Spellings, SemanticToSyntacticMap);
     unsigned SpellingIdx = 0;
     for (const auto &S : Spellings) {
       std::string Spelling;
@@ -2777,6 +2753,16 @@
       OS << "struct " << AttrInfoName << " : public ParsedAttrInfo {\n";
       OS << "  " << AttrInfoName << "() {\n";
       OS << "    SpellingListIndex = " << SpellingIdx << ";\n";
+      // If the attribute does not have a semantic form, has at most one
+      // spelling, or all spellings share the same name then it has no semantic
+      // spelling.
+      if (!Attr.getValueAsBit("ASTNode") || Spellings.size() <= 1 ||
+          SpellingNamesAreCommon(Spellings)) {
+        OS << "    SemanticSpelling = UINT_MAX;\n";
+      } else {
+        OS << "    SemanticSpelling = " << Attr.getName() << "Attr::"
+           << SemanticToSyntacticMap[SpellingIdx] << ";\n";
+      }
       if (Attr.getValueAsBit("Ignored")) {
         OS << "    AttrKind = AttributeList::IgnoredAttribute;\n";
       } else {
@@ -2806,7 +2792,6 @@
       GenerateAppertainsTo(Attr, OS);
       GenerateLangOptRequirements(Attr, OS);
       GenerateTargetRequirements(Attr, Dupes, OS);
-      GenerateSpellingIndexToSemanticSpelling(Attr, OS);
       OS << "};\n";
       OS << "static AttrInfoRegistry::Add<" << AttrInfoName << "> " << AttrInfoName << "Instance(\"" << Spelling << "\",\"\");\n";
       ++SpellingIdx;