diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
--- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
@@ -3205,6 +3205,8 @@
   Record *AsmParser = Target.getAsmParser();
   StringRef ClassName = AsmParser->getValueAsString("AsmParserClassName");
 
+  emitSourceFileHeader("Assembly Matcher Source Fragment", OS);
+
   // Compute the information on the instructions to match.
   AsmMatcherInfo Info(AsmParser, Target, Records);
   Info.buildInfo();
@@ -4002,11 +4004,5 @@
   OS << "#endif // GET_MNEMONIC_CHECKER\n\n";
 }
 
-namespace llvm {
-
-void EmitAsmMatcher(RecordKeeper &RK, raw_ostream &OS) {
-  emitSourceFileHeader("Assembly Matcher Source Fragment", OS);
-  AsmMatcherEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<AsmMatcherEmitter>
+    X("gen-asm-matcher", "Generate assembly instruction matcher");
diff --git a/llvm/utils/TableGen/AsmWriterEmitter.cpp b/llvm/utils/TableGen/AsmWriterEmitter.cpp
--- a/llvm/utils/TableGen/AsmWriterEmitter.cpp
+++ b/llvm/utils/TableGen/AsmWriterEmitter.cpp
@@ -1300,17 +1300,12 @@
   std::vector<std::vector<std::string>> TableDrivenOperandPrinters;
   unsigned BitsLeft = 0;
   unsigned AsmStrBits = 0;
+  emitSourceFileHeader("Assembly Writer Source Fragment", O);
   EmitGetMnemonic(O, TableDrivenOperandPrinters, BitsLeft, AsmStrBits);
   EmitPrintInstruction(O, TableDrivenOperandPrinters, BitsLeft, AsmStrBits);
   EmitGetRegisterName(O);
   EmitPrintAliasInstruction(O);
 }
 
-namespace llvm {
-
-void EmitAsmWriter(RecordKeeper &RK, raw_ostream &OS) {
-  emitSourceFileHeader("Assembly Writer Source Fragment", OS);
-  AsmWriterEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<AsmWriterEmitter>
+    X("gen-asm-writer", "Generate assembly writer");
diff --git a/llvm/utils/TableGen/Attributes.cpp b/llvm/utils/TableGen/Attributes.cpp
--- a/llvm/utils/TableGen/Attributes.cpp
+++ b/llvm/utils/TableGen/Attributes.cpp
@@ -18,7 +18,7 @@
 class Attributes {
 public:
   Attributes(RecordKeeper &R) : Records(R) {}
-  void emit(raw_ostream &OS);
+  void run(raw_ostream &OS);
 
 private:
   void emitTargetIndependentNames(raw_ostream &OS);
@@ -124,16 +124,11 @@
   OS << "#endif\n";
 }
 
-void Attributes::emit(raw_ostream &OS) {
+void Attributes::run(raw_ostream &OS) {
   emitTargetIndependentNames(OS);
   emitFnAttrCompatCheck(OS, false);
   emitAttributeProperties(OS);
 }
 
-namespace llvm {
-
-void EmitAttributes(RecordKeeper &RK, raw_ostream &OS) {
-  Attributes(RK).emit(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<Attributes> X("gen-attrs",
+                                                 "Generate attributes");
diff --git a/llvm/utils/TableGen/CTagsEmitter.cpp b/llvm/utils/TableGen/CTagsEmitter.cpp
--- a/llvm/utils/TableGen/CTagsEmitter.cpp
+++ b/llvm/utils/TableGen/CTagsEmitter.cpp
@@ -86,8 +86,5 @@
     T.emit(OS);
 }
 
-namespace llvm {
-
-void EmitCTags(RecordKeeper &RK, raw_ostream &OS) { CTagsEmitter(RK).run(OS); }
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<CTagsEmitter>
+    X("gen-ctags", "Generate ctags-compatible index");
diff --git a/llvm/utils/TableGen/CallingConvEmitter.cpp b/llvm/utils/TableGen/CallingConvEmitter.cpp
--- a/llvm/utils/TableGen/CallingConvEmitter.cpp
+++ b/llvm/utils/TableGen/CallingConvEmitter.cpp
@@ -42,6 +42,8 @@
 } // End anonymous namespace
 
 void CallingConvEmitter::run(raw_ostream &O) {
+  emitSourceFileHeader("Calling Convention Implementation Fragment", O);
+
   std::vector<Record *> CCs = Records.getAllDerivedDefinitions("CallingConv");
 
   // Emit prototypes for all of the non-custom CC's so that they can forward ref
@@ -427,11 +429,5 @@
   }
 }
 
-namespace llvm {
-
-void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS) {
-  emitSourceFileHeader("Calling Convention Implementation Fragment", OS);
-  CallingConvEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<CallingConvEmitter>
+    X("gen-callingconv", "Generate calling convention descriptions");
diff --git a/llvm/utils/TableGen/CodeEmitterGen.cpp b/llvm/utils/TableGen/CodeEmitterGen.cpp
--- a/llvm/utils/TableGen/CodeEmitterGen.cpp
+++ b/llvm/utils/TableGen/CodeEmitterGen.cpp
@@ -421,6 +421,8 @@
 }
 
 void CodeEmitterGen::run(raw_ostream &o) {
+  emitSourceFileHeader("Machine Code Emitter", o);
+
   CodeGenTarget Target(Records);
   std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
 
@@ -565,11 +567,5 @@
 
 } // end anonymous namespace
 
-namespace llvm {
-
-void EmitCodeEmitter(RecordKeeper &RK, raw_ostream &OS) {
-  emitSourceFileHeader("Machine Code Emitter", OS);
-  CodeEmitterGen(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<CodeEmitterGen>
+    X("gen-emitter", "Generate machine code emitter");
diff --git a/llvm/utils/TableGen/CompressInstEmitter.cpp b/llvm/utils/TableGen/CompressInstEmitter.cpp
--- a/llvm/utils/TableGen/CompressInstEmitter.cpp
+++ b/llvm/utils/TableGen/CompressInstEmitter.cpp
@@ -904,10 +904,5 @@
   emitCompressInstEmitter(o, EmitterType::CheckCompress);
 }
 
-namespace llvm {
-
-void EmitCompressInst(RecordKeeper &RK, raw_ostream &OS) {
-  CompressInstEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<CompressInstEmitter>
+    X("gen-compress-inst-emitter", "Generate RISCV compressed instructions.");
diff --git a/llvm/utils/TableGen/DAGISelEmitter.cpp b/llvm/utils/TableGen/DAGISelEmitter.cpp
--- a/llvm/utils/TableGen/DAGISelEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelEmitter.cpp
@@ -125,6 +125,7 @@
 
 
 void DAGISelEmitter::run(raw_ostream &OS) {
+  Records.startTimer("Parse patterns");
   emitSourceFileHeader("DAG Instruction Selector for the " +
                        CGP.getTargetInfo().getName().str() + " target", OS);
 
@@ -187,11 +188,5 @@
   EmitMatcherTable(TheMatcher.get(), CGP, OS);
 }
 
-namespace llvm {
-
-void EmitDAGISel(RecordKeeper &RK, raw_ostream &OS) {
-  RK.startTimer("Parse patterns");
-  DAGISelEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<DAGISelEmitter>
+    X("gen-dag-isel", "Generate a DAG instruction selector");
diff --git a/llvm/utils/TableGen/DFAEmitter.cpp b/llvm/utils/TableGen/DFAEmitter.cpp
--- a/llvm/utils/TableGen/DFAEmitter.cpp
+++ b/llvm/utils/TableGen/DFAEmitter.cpp
@@ -370,10 +370,5 @@
     OS << ")";
 }
 
-namespace llvm {
-
-void EmitAutomata(RecordKeeper &RK, raw_ostream &OS) {
-  AutomatonEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<AutomatonEmitter>
+    X("gen-automata", "Generate generic automata");
diff --git a/llvm/utils/TableGen/DFAPacketizerEmitter.cpp b/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
--- a/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
+++ b/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
@@ -206,6 +206,7 @@
 // Run the worklist algorithm to generate the DFA.
 //
 void DFAPacketizerEmitter::run(raw_ostream &OS) {
+  emitSourceFileHeader("Target DFA Packetizer Tables", OS);
   OS << "\n"
      << "#include \"llvm/CodeGen/DFAPacketizer.h\"\n";
   OS << "namespace llvm {\n";
@@ -353,11 +354,5 @@
      << "\n}\n\n";
 }
 
-namespace llvm {
-
-void EmitDFAPacketizer(RecordKeeper &RK, raw_ostream &OS) {
-  emitSourceFileHeader("Target DFA Packetizer Tables", OS);
-  DFAPacketizerEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<DFAPacketizerEmitter>
+    X("gen-dfa-packetizer", "Generate DFA Packetizer for VLIW targets");
diff --git a/llvm/utils/TableGen/DXILEmitter.cpp b/llvm/utils/TableGen/DXILEmitter.cpp
--- a/llvm/utils/TableGen/DXILEmitter.cpp
+++ b/llvm/utils/TableGen/DXILEmitter.cpp
@@ -411,9 +411,7 @@
   OS << "}\n ";
 }
 
-namespace llvm {
-
-void EmitDXILOperation(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitDXILOperation(RecordKeeper &Records, raw_ostream &OS) {
   std::vector<Record *> Ops = Records.getAllDerivedDefinitions("dxil_op");
   OS << "// Generated code, do not edit.\n";
   OS << "\n";
@@ -439,4 +437,5 @@
   OS << "\n";
 }
 
-} // namespace llvm
+static TableGen::Emitter::Opt X("gen-dxil-operation", EmitDXILOperation,
+                                "Generate DXIL operation information");
diff --git a/llvm/utils/TableGen/DecoderEmitter.cpp b/llvm/utils/TableGen/DecoderEmitter.cpp
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -15,6 +15,7 @@
 #include "CodeGenInstruction.h"
 #include "CodeGenTarget.h"
 #include "InfoByHwMode.h"
+#include "TableGenBackends.h"
 #include "VarLenCodeEmitterGen.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/ArrayRef.h"
diff --git a/llvm/utils/TableGen/DirectiveEmitter.cpp b/llvm/utils/TableGen/DirectiveEmitter.cpp
--- a/llvm/utils/TableGen/DirectiveEmitter.cpp
+++ b/llvm/utils/TableGen/DirectiveEmitter.cpp
@@ -174,11 +174,9 @@
   return HasDuplicateClausesInDirectives(getDirectives());
 }
 
-namespace llvm {
-
 // Generate the declaration section for the enumeration in the directive
 // language
-void EmitDirectivesDecl(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitDirectivesDecl(RecordKeeper &Records, raw_ostream &OS) {
   const auto DirLang = DirectiveLanguage{Records};
   if (DirLang.HasValidityErrors())
     return;
@@ -247,8 +245,6 @@
   OS << "#endif // LLVM_" << DirLang.getName() << "_INC\n";
 }
 
-} // namespace llvm
-
 // Generate function implementation for get<Enum>Name(StringRef Str)
 static void GenerateGetName(const std::vector<Record *> &Records,
                             raw_ostream &OS, StringRef Enum,
@@ -877,11 +873,9 @@
   GenerateIsAllowedClause(DirLang, OS);
 }
 
-namespace llvm {
-
 // Generate the implemenation section for the enumeration in the directive
 // language.
-void EmitDirectivesImpl(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitDirectivesImpl(RecordKeeper &Records, raw_ostream &OS) {
   const auto DirLang = DirectiveLanguage{Records};
   if (DirLang.HasValidityErrors())
     return;
@@ -893,4 +887,10 @@
   EmitDirectivesBasicImpl(DirLang, OS);
 }
 
-} // namespace llvm
+static TableGen::Emitter::Opt
+    X("gen-directive-decl", EmitDirectivesDecl,
+      "Generate directive related declaration code (header file)");
+
+static TableGen::Emitter::Opt
+    Y("gen-directive-impl", EmitDirectivesImpl,
+      "Generate directive related implementation code");
diff --git a/llvm/utils/TableGen/DisassemblerEmitter.cpp b/llvm/utils/TableGen/DisassemblerEmitter.cpp
--- a/llvm/utils/TableGen/DisassemblerEmitter.cpp
+++ b/llvm/utils/TableGen/DisassemblerEmitter.cpp
@@ -94,12 +94,7 @@
 /// X86RecognizableInstr.cpp contains the implementation for a single
 ///   instruction.
 
-namespace llvm {
-
-extern void EmitDecoder(RecordKeeper &RK, raw_ostream &OS,
-                        const std::string &PredicateNamespace);
-
-void EmitDisassembler(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitDisassembler(RecordKeeper &Records, raw_ostream &OS) {
   CodeGenTarget Target(Records);
   emitSourceFileHeader(" * " + Target.getName().str() + " Disassembler", OS);
 
@@ -136,4 +131,5 @@
   EmitDecoder(Records, OS, PredicateNamespace);
 }
 
-} // end namespace llvm
+static TableGen::Emitter::Opt X("gen-disassembler", EmitDisassembler,
+                                "Generate disassembler");
diff --git a/llvm/utils/TableGen/ExegesisEmitter.cpp b/llvm/utils/TableGen/ExegesisEmitter.cpp
--- a/llvm/utils/TableGen/ExegesisEmitter.cpp
+++ b/llvm/utils/TableGen/ExegesisEmitter.cpp
@@ -203,10 +203,5 @@
 
 } // end anonymous namespace
 
-namespace llvm {
-
-void EmitExegesis(RecordKeeper &RK, raw_ostream &OS) {
-  ExegesisEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<ExegesisEmitter>
+    X("gen-exegesis", "Generate llvm-exegesis tables");
diff --git a/llvm/utils/TableGen/FastISelEmitter.cpp b/llvm/utils/TableGen/FastISelEmitter.cpp
--- a/llvm/utils/TableGen/FastISelEmitter.cpp
+++ b/llvm/utils/TableGen/FastISelEmitter.cpp
@@ -858,9 +858,7 @@
   // TODO: SignaturesWithConstantForms should be empty here.
 }
 
-namespace llvm {
-
-void EmitFastISel(RecordKeeper &RK, raw_ostream &OS) {
+static void EmitFastISel(RecordKeeper &RK, raw_ostream &OS) {
   CodeGenDAGPatterns CGP(RK);
   const CodeGenTarget &Target = CGP.getTargetInfo();
   emitSourceFileHeader("\"Fast\" Instruction Selector for the " +
@@ -876,4 +874,5 @@
   F.printFunctionDefinitions(OS);
 }
 
-} // namespace llvm
+static TableGen::Emitter::Opt X("gen-fast-isel", EmitFastISel,
+                                "Generate a \"fast\" instruction selector");
diff --git a/llvm/utils/TableGen/GICombinerEmitter.cpp b/llvm/utils/TableGen/GICombinerEmitter.cpp
--- a/llvm/utils/TableGen/GICombinerEmitter.cpp
+++ b/llvm/utils/TableGen/GICombinerEmitter.cpp
@@ -1067,8 +1067,7 @@
 
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-void EmitGICombiner(RecordKeeper &RK, raw_ostream &OS) {
+static void EmitGICombiner(RecordKeeper &RK, raw_ostream &OS) {
   CodeGenTarget Target(RK);
   emitSourceFileHeader("Global Combiner", OS);
 
@@ -1083,4 +1082,5 @@
   NumPatternTotalStatistic = NumPatternTotal;
 }
 
-} // namespace llvm
+static TableGen::Emitter::Opt X("gen-global-isel-combiner", EmitGICombiner,
+                                "Generate GlobalISel combiner");
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -6363,8 +6363,5 @@
 
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-void EmitGlobalISel(RecordKeeper &RK, raw_ostream &OS) {
-  GlobalISelEmitter(RK).run(OS);
-}
-} // namespace llvm
+static TableGen::Emitter::OptClass<GlobalISelEmitter>
+    X("gen-global-isel", "Generate GlobalISel selector");
diff --git a/llvm/utils/TableGen/InstrDocsEmitter.cpp b/llvm/utils/TableGen/InstrDocsEmitter.cpp
--- a/llvm/utils/TableGen/InstrDocsEmitter.cpp
+++ b/llvm/utils/TableGen/InstrDocsEmitter.cpp
@@ -54,9 +54,7 @@
   return Result;
 }
 
-namespace llvm {
-
-void EmitInstrDocs(RecordKeeper &RK, raw_ostream &OS) {
+static void EmitInstrDocs(RecordKeeper &RK, raw_ostream &OS) {
   CodeGenDAGPatterns CDP(RK);
   CodeGenTarget &Target = CDP.getTargetInfo();
   unsigned VariantCount = Target.getAsmParserVariantCount();
@@ -217,4 +215,5 @@
   }
 }
 
-} // end namespace llvm
+static TableGen::Emitter::Opt X("gen-instr-docs", EmitInstrDocs,
+                                "Generate instruction documentation");
diff --git a/llvm/utils/TableGen/InstrInfoEmitter.cpp b/llvm/utils/TableGen/InstrInfoEmitter.cpp
--- a/llvm/utils/TableGen/InstrInfoEmitter.cpp
+++ b/llvm/utils/TableGen/InstrInfoEmitter.cpp
@@ -1245,13 +1245,12 @@
   OS << "#endif // GET_INSTRINFO_SCHED_ENUM\n\n";
 }
 
-namespace llvm {
-
-void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS) {
+static void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS) {
   RK.startTimer("Analyze DAG patterns");
   InstrInfoEmitter(RK).run(OS);
   RK.startTimer("Emit map table");
   EmitMapTable(RK, OS);
 }
 
-} // end namespace llvm
+static TableGen::Emitter::Opt X("gen-instr-info", EmitInstrInfo,
+                                "Generate instruction descriptions");
diff --git a/llvm/utils/TableGen/IntrinsicEmitter.cpp b/llvm/utils/TableGen/IntrinsicEmitter.cpp
--- a/llvm/utils/TableGen/IntrinsicEmitter.cpp
+++ b/llvm/utils/TableGen/IntrinsicEmitter.cpp
@@ -967,10 +967,16 @@
   OS << "#endif\n\n";
 }
 
-void llvm::EmitIntrinsicEnums(RecordKeeper &RK, raw_ostream &OS) {
+static void EmitIntrinsicEnums(RecordKeeper &RK, raw_ostream &OS) {
   IntrinsicEmitter(RK).run(OS, /*Enums=*/true);
 }
 
-void llvm::EmitIntrinsicImpl(RecordKeeper &RK, raw_ostream &OS) {
+static TableGen::Emitter::Opt X("gen-intrinsic-enums", EmitIntrinsicEnums,
+                                "Generate intrinsic enums");
+
+static void EmitIntrinsicImpl(RecordKeeper &RK, raw_ostream &OS) {
   IntrinsicEmitter(RK).run(OS, /*Enums=*/false);
 }
+
+static TableGen::Emitter::Opt Y("gen-intrinsic-impl", EmitIntrinsicImpl,
+                                "Generate intrinsic information");
diff --git a/llvm/utils/TableGen/OptParserEmitter.cpp b/llvm/utils/TableGen/OptParserEmitter.cpp
--- a/llvm/utils/TableGen/OptParserEmitter.cpp
+++ b/llvm/utils/TableGen/OptParserEmitter.cpp
@@ -213,8 +213,7 @@
 /// OptParserEmitter - This tablegen backend takes an input .td file
 /// describing a list of options and emits a data structure for parsing and
 /// working with those options when given an input command line.
-namespace llvm {
-void EmitOptParser(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitOptParser(RecordKeeper &Records, raw_ostream &OS) {
   // Get the option groups and options.
   const std::vector<Record*> &Groups =
     Records.getAllDerivedDefinitions("OptionGroup");
@@ -500,4 +499,6 @@
 
   OS << "\n";
 }
-} // end namespace llvm
+
+static TableGen::Emitter::Opt X("gen-opt-parser-defs", EmitOptParser,
+                                "Generate option definitions");
diff --git a/llvm/utils/TableGen/OptRSTEmitter.cpp b/llvm/utils/TableGen/OptRSTEmitter.cpp
--- a/llvm/utils/TableGen/OptRSTEmitter.cpp
+++ b/llvm/utils/TableGen/OptRSTEmitter.cpp
@@ -16,8 +16,7 @@
 
 /// OptParserEmitter - This tablegen backend takes an input .td file
 /// describing a list of options and emits a RST man page.
-namespace llvm {
-void EmitOptRST(RecordKeeper &Records, raw_ostream &OS) {
+static void EmitOptRST(RecordKeeper &Records, raw_ostream &OS) {
   llvm::StringMap<std::vector<Record *>> OptionsByGroup;
   std::vector<Record *> OptionsWithoutGroup;
 
@@ -103,4 +102,6 @@
     }
   }
 }
-} // end namespace llvm
+
+static TableGen::Emitter::Opt X("gen-opt-rst", EmitOptRST,
+                                "Generate option RST");
diff --git a/llvm/utils/TableGen/PseudoLoweringEmitter.cpp b/llvm/utils/TableGen/PseudoLoweringEmitter.cpp
--- a/llvm/utils/TableGen/PseudoLoweringEmitter.cpp
+++ b/llvm/utils/TableGen/PseudoLoweringEmitter.cpp
@@ -314,10 +314,5 @@
   emitLoweringEmitter(o);
 }
 
-namespace llvm {
-
-void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS) {
-  PseudoLoweringEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<PseudoLoweringEmitter>
+    X("gen-pseudo-lowering", "Generate pseudo instruction lowering");
diff --git a/llvm/utils/TableGen/RISCVTargetDefEmitter.cpp b/llvm/utils/TableGen/RISCVTargetDefEmitter.cpp
--- a/llvm/utils/TableGen/RISCVTargetDefEmitter.cpp
+++ b/llvm/utils/TableGen/RISCVTargetDefEmitter.cpp
@@ -47,7 +47,7 @@
   return (*ISAInfo)->toString();
 }
 
-void llvm::EmitRISCVTargetDef(const RecordKeeper &RK, raw_ostream &OS) {
+static void EmitRISCVTargetDef(RecordKeeper &RK, raw_ostream &OS) {
   OS << "#ifndef PROC\n"
      << "#define PROC(ENUM, NAME, DEFAULT_MARCH)\n"
      << "#endif\n\n";
@@ -80,3 +80,6 @@
 
   OS << "\n#undef TUNE_PROC\n";
 }
+
+static TableGen::Emitter::Opt X("gen-riscv-target-def", EmitRISCVTargetDef,
+                                "Generate the list of CPU for RISCV");
diff --git a/llvm/utils/TableGen/RegisterBankEmitter.cpp b/llvm/utils/TableGen/RegisterBankEmitter.cpp
--- a/llvm/utils/TableGen/RegisterBankEmitter.cpp
+++ b/llvm/utils/TableGen/RegisterBankEmitter.cpp
@@ -328,10 +328,5 @@
   OS << "#endif // GET_TARGET_REGBANK_IMPL\n";
 }
 
-namespace llvm {
-
-void EmitRegisterBank(RecordKeeper &RK, raw_ostream &OS) {
-  RegisterBankEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<RegisterBankEmitter>
+    X("gen-register-bank", "Generate registers bank descriptions");
diff --git a/llvm/utils/TableGen/RegisterInfoEmitter.cpp b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
--- a/llvm/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
@@ -1909,10 +1909,5 @@
   }
 }
 
-namespace llvm {
-
-void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS) {
-  RegisterInfoEmitter(RK).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<RegisterInfoEmitter>
+    X("gen-register-info", "Generate registers and register classes info");
diff --git a/llvm/utils/TableGen/SearchableTableEmitter.cpp b/llvm/utils/TableGen/SearchableTableEmitter.cpp
--- a/llvm/utils/TableGen/SearchableTableEmitter.cpp
+++ b/llvm/utils/TableGen/SearchableTableEmitter.cpp
@@ -823,10 +823,5 @@
     OS << "#undef " << Guard << "\n";
 }
 
-namespace llvm {
-
-void EmitSearchableTables(RecordKeeper &RK, raw_ostream &OS) {
-  SearchableTableEmitter(RK).run(OS);
-}
-
-} // namespace llvm
+static TableGen::Emitter::OptClass<SearchableTableEmitter>
+    X("gen-searchable-tables", "Generate generic binary-searchable table");
diff --git a/llvm/utils/TableGen/SubtargetEmitter.cpp b/llvm/utils/TableGen/SubtargetEmitter.cpp
--- a/llvm/utils/TableGen/SubtargetEmitter.cpp
+++ b/llvm/utils/TableGen/SubtargetEmitter.cpp
@@ -70,7 +70,7 @@
     }
   };
 
-  const CodeGenTarget &TGT;
+  CodeGenTarget TGT;
   RecordKeeper &Records;
   CodeGenSchedModels &SchedModels;
   std::string Target;
@@ -128,8 +128,8 @@
   void ParseFeaturesFunction(raw_ostream &OS);
 
 public:
-  SubtargetEmitter(RecordKeeper &R, CodeGenTarget &TGT)
-      : TGT(TGT), Records(R), SchedModels(TGT.getSchedModels()),
+  SubtargetEmitter(RecordKeeper &R)
+      : TGT(R), Records(R), SchedModels(TGT.getSchedModels()),
         Target(TGT.getName()) {}
 
   void run(raw_ostream &o);
@@ -1985,11 +1985,5 @@
   EmitMCInstrAnalysisPredicateFunctions(OS);
 }
 
-namespace llvm {
-
-void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS) {
-  CodeGenTarget CGTarget(RK);
-  SubtargetEmitter(RK, CGTarget).run(OS);
-}
-
-} // end namespace llvm
+static TableGen::Emitter::OptClass<SubtargetEmitter>
+    X("gen-subtarget", "Generate subtarget enumerations");
diff --git a/llvm/utils/TableGen/TableGen.cpp b/llvm/utils/TableGen/TableGen.cpp
--- a/llvm/utils/TableGen/TableGen.cpp
+++ b/llvm/utils/TableGen/TableGen.cpp
@@ -13,6 +13,7 @@
 #include "TableGenBackends.h" // Declares all backends.
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TableGen/Main.h"
 #include "llvm/TableGen/Record.h"
@@ -23,48 +24,6 @@
 
 using namespace llvm;
 
-enum ActionType {
-  PrintRecords,
-  PrintDetailedRecords,
-  NullBackend,
-  DumpJSON,
-  GenEmitter,
-  GenRegisterInfo,
-  GenInstrInfo,
-  GenInstrDocs,
-  GenAsmWriter,
-  GenAsmMatcher,
-  GenDisassembler,
-  GenPseudoLowering,
-  GenCompressInst,
-  GenCallingConv,
-  GenDAGISel,
-  GenDFAPacketizer,
-  GenFastISel,
-  GenSubtarget,
-  GenIntrinsicEnums,
-  GenIntrinsicImpl,
-  PrintEnums,
-  PrintSets,
-  GenOptParserDefs,
-  GenOptRST,
-  GenCTags,
-  GenAttributes,
-  GenSearchableTables,
-  GenGlobalISel,
-  GenGICombiner,
-  GenX86EVEX2VEXTables,
-  GenX86FoldTables,
-  GenX86MnemonicTables,
-  GenRegisterBank,
-  GenExegesis,
-  GenAutomata,
-  GenDirectivesEnumDecl,
-  GenDirectivesEnumImpl,
-  GenDXILOperation,
-  GenRISCVTargetDef,
-};
-
 namespace llvm {
 cl::opt<bool> EmitLongStrLiterals(
     "long-string-literals",
@@ -74,223 +33,67 @@
     cl::Hidden, cl::init(true));
 } // end namespace llvm
 
+namespace llvm {
+namespace TableGen {
+namespace Emitter {
+ManagedStatic<cl::opt<FnT>, OptCreatorT> Action;
+void *OptCreatorT::call() {
+  return new cl::opt<FnT>(cl::desc("Action to perform:"));
+}
+} // namespace Emitter
+} // namespace TableGen
+} // namespace llvm
+
 namespace {
-cl::opt<ActionType> Action(
-    cl::desc("Action to perform:"),
-    cl::values(
-        clEnumValN(PrintRecords, "print-records",
-                   "Print all records to stdout (default)"),
-        clEnumValN(PrintDetailedRecords, "print-detailed-records",
-                   "Print full details of all records to stdout"),
-        clEnumValN(NullBackend, "null-backend",
-                   "Do nothing after parsing (useful for timing)"),
-        clEnumValN(DumpJSON, "dump-json",
-                   "Dump all records as machine-readable JSON"),
-        clEnumValN(GenEmitter, "gen-emitter", "Generate machine code emitter"),
-        clEnumValN(GenRegisterInfo, "gen-register-info",
-                   "Generate registers and register classes info"),
-        clEnumValN(GenInstrInfo, "gen-instr-info",
-                   "Generate instruction descriptions"),
-        clEnumValN(GenInstrDocs, "gen-instr-docs",
-                   "Generate instruction documentation"),
-        clEnumValN(GenCallingConv, "gen-callingconv",
-                   "Generate calling convention descriptions"),
-        clEnumValN(GenAsmWriter, "gen-asm-writer", "Generate assembly writer"),
-        clEnumValN(GenDisassembler, "gen-disassembler",
-                   "Generate disassembler"),
-        clEnumValN(GenPseudoLowering, "gen-pseudo-lowering",
-                   "Generate pseudo instruction lowering"),
-        clEnumValN(GenCompressInst, "gen-compress-inst-emitter",
-                   "Generate RISCV compressed instructions."),
-        clEnumValN(GenAsmMatcher, "gen-asm-matcher",
-                   "Generate assembly instruction matcher"),
-        clEnumValN(GenDAGISel, "gen-dag-isel",
-                   "Generate a DAG instruction selector"),
-        clEnumValN(GenDFAPacketizer, "gen-dfa-packetizer",
-                   "Generate DFA Packetizer for VLIW targets"),
-        clEnumValN(GenFastISel, "gen-fast-isel",
-                   "Generate a \"fast\" instruction selector"),
-        clEnumValN(GenSubtarget, "gen-subtarget",
-                   "Generate subtarget enumerations"),
-        clEnumValN(GenIntrinsicEnums, "gen-intrinsic-enums",
-                   "Generate intrinsic enums"),
-        clEnumValN(GenIntrinsicImpl, "gen-intrinsic-impl",
-                   "Generate intrinsic information"),
-        clEnumValN(PrintEnums, "print-enums", "Print enum values for a class"),
-        clEnumValN(PrintSets, "print-sets",
-                   "Print expanded sets for testing DAG exprs"),
-        clEnumValN(GenOptParserDefs, "gen-opt-parser-defs",
-                   "Generate option definitions"),
-        clEnumValN(GenOptRST, "gen-opt-rst", "Generate option RST"),
-        clEnumValN(GenCTags, "gen-ctags", "Generate ctags-compatible index"),
-        clEnumValN(GenAttributes, "gen-attrs", "Generate attributes"),
-        clEnumValN(GenSearchableTables, "gen-searchable-tables",
-                   "Generate generic binary-searchable table"),
-        clEnumValN(GenGlobalISel, "gen-global-isel",
-                   "Generate GlobalISel selector"),
-        clEnumValN(GenGICombiner, "gen-global-isel-combiner",
-                   "Generate GlobalISel combiner"),
-        clEnumValN(GenX86EVEX2VEXTables, "gen-x86-EVEX2VEX-tables",
-                   "Generate X86 EVEX to VEX compress tables"),
-        clEnumValN(GenX86FoldTables, "gen-x86-fold-tables",
-                   "Generate X86 fold tables"),
-        clEnumValN(GenX86MnemonicTables, "gen-x86-mnemonic-tables",
-                   "Generate X86 mnemonic tables"),
-        clEnumValN(GenRegisterBank, "gen-register-bank",
-                   "Generate registers bank descriptions"),
-        clEnumValN(GenExegesis, "gen-exegesis",
-                   "Generate llvm-exegesis tables"),
-        clEnumValN(GenAutomata, "gen-automata", "Generate generic automata"),
-        clEnumValN(GenDirectivesEnumDecl, "gen-directive-decl",
-                   "Generate directive related declaration code (header file)"),
-        clEnumValN(GenDirectivesEnumImpl, "gen-directive-impl",
-                   "Generate directive related implementation code"),
-        clEnumValN(GenDXILOperation, "gen-dxil-operation",
-                   "Generate DXIL operation information"),
-        clEnumValN(GenRISCVTargetDef, "gen-riscv-target-def",
-                   "Generate the list of CPU for RISCV")));
+
 cl::OptionCategory PrintEnumsCat("Options for -print-enums");
 cl::opt<std::string> Class("class", cl::desc("Print Enum list for this class"),
                            cl::value_desc("class name"),
                            cl::cat(PrintEnumsCat));
 
-bool LLVMTableGenMain(raw_ostream &OS, RecordKeeper &Records) {
-  switch (Action) {
-  case PrintRecords:
-    OS << Records;              // No argument, dump all contents
-    break;
-  case PrintDetailedRecords:
-    EmitDetailedRecords(Records, OS);
-    break;
-  case NullBackend:             // No backend at all.
-    break;
-  case DumpJSON:
-    EmitJSON(Records, OS);
-    break;
-  case GenEmitter:
-    EmitCodeEmitter(Records, OS);
-    break;
-  case GenRegisterInfo:
-    EmitRegisterInfo(Records, OS);
-    break;
-  case GenInstrInfo:
-    EmitInstrInfo(Records, OS);
-    break;
-  case GenInstrDocs:
-    EmitInstrDocs(Records, OS);
-    break;
-  case GenCallingConv:
-    EmitCallingConv(Records, OS);
-    break;
-  case GenAsmWriter:
-    EmitAsmWriter(Records, OS);
-    break;
-  case GenAsmMatcher:
-    EmitAsmMatcher(Records, OS);
-    break;
-  case GenDisassembler:
-    EmitDisassembler(Records, OS);
-    break;
-  case GenPseudoLowering:
-    EmitPseudoLowering(Records, OS);
-    break;
-  case GenCompressInst:
-    EmitCompressInst(Records, OS);
-    break;
-  case GenDAGISel:
-    EmitDAGISel(Records, OS);
-    break;
-  case GenDFAPacketizer:
-    EmitDFAPacketizer(Records, OS);
-    break;
-  case GenFastISel:
-    EmitFastISel(Records, OS);
-    break;
-  case GenSubtarget:
-    EmitSubtarget(Records, OS);
-    break;
-  case GenIntrinsicEnums:
-    EmitIntrinsicEnums(Records, OS);
-    break;
-  case GenIntrinsicImpl:
-    EmitIntrinsicImpl(Records, OS);
-    break;
-  case GenOptParserDefs:
-    EmitOptParser(Records, OS);
-    break;
-  case GenOptRST:
-    EmitOptRST(Records, OS);
-    break;
-  case PrintEnums: {
-    for (Record *Rec : Records.getAllDerivedDefinitions(Class))
-      OS << Rec->getName() << ", ";
-    OS << "\n";
-    break;
-  }
-  case PrintSets:
-  {
-    SetTheory Sets;
-    Sets.addFieldExpander("Set", "Elements");
-    for (Record *Rec : Records.getAllDerivedDefinitions("Set")) {
-      OS << Rec->getName() << " = [";
-      const std::vector<Record*> *Elts = Sets.expand(Rec);
-      assert(Elts && "Couldn't expand Set instance");
-      for (Record *Elt : *Elts)
-        OS << ' ' << Elt->getName();
-      OS << " ]\n";
-    }
-    break;
-  }
-  case GenCTags:
-    EmitCTags(Records, OS);
-    break;
-  case GenAttributes:
-    EmitAttributes(Records, OS);
-    break;
-  case GenSearchableTables:
-    EmitSearchableTables(Records, OS);
-    break;
-  case GenGlobalISel:
-    EmitGlobalISel(Records, OS);
-    break;
-  case GenGICombiner:
-    EmitGICombiner(Records, OS);
-    break;
-  case GenRegisterBank:
-    EmitRegisterBank(Records, OS);
-    break;
-  case GenX86EVEX2VEXTables:
-    EmitX86EVEX2VEXTables(Records, OS);
-    break;
-  case GenX86MnemonicTables:
-    EmitX86MnemonicTables(Records, OS);
-    break;
-  case GenX86FoldTables:
-    EmitX86FoldTables(Records, OS);
-    break;
-  case GenExegesis:
-    EmitExegesis(Records, OS);
-    break;
-  case GenAutomata:
-    EmitAutomata(Records, OS);
-    break;
-  case GenDirectivesEnumDecl:
-    EmitDirectivesDecl(Records, OS);
-    break;
-  case GenDirectivesEnumImpl:
-    EmitDirectivesImpl(Records, OS);
-    break;
-  case GenDXILOperation:
-    EmitDXILOperation(Records, OS);
-    break;
-  case GenRISCVTargetDef:
-    EmitRISCVTargetDef(Records, OS);
-    break;
+void PrintRecords(RecordKeeper &Records, raw_ostream &OS) {
+  OS << Records; // No argument, dump all contents
+}
+
+void PrintEnums(RecordKeeper &Records, raw_ostream &OS) {
+  for (Record *Rec : Records.getAllDerivedDefinitions(Class))
+    OS << Rec->getName() << ", ";
+  OS << "\n";
+}
+
+void PrintSets(RecordKeeper &Records, raw_ostream &OS) {
+  SetTheory Sets;
+  Sets.addFieldExpander("Set", "Elements");
+  for (Record *Rec : Records.getAllDerivedDefinitions("Set")) {
+    OS << Rec->getName() << " = [";
+    const std::vector<Record *> *Elts = Sets.expand(Rec);
+    assert(Elts && "Couldn't expand Set instance");
+    for (Record *Elt : *Elts)
+      OS << ' ' << Elt->getName();
+    OS << " ]\n";
   }
+}
 
+bool LLVMTableGenMain(raw_ostream &OS, RecordKeeper &Records) {
+  auto ActionFn = TableGen::Emitter::Action->getValue();
+  assert(ActionFn != nullptr);
+  ActionFn(Records, OS);
   return false;
 }
-}
+
+TableGen::Emitter::Opt X[] = {
+    {"print-records", PrintRecords, "Print all records to stdout (default)",
+     true},
+    {"print-detailed-records", EmitDetailedRecords,
+     "Print full details of all records to stdout"},
+    {"null-backend", [](RecordKeeper &Records, raw_ostream &OS) {},
+     "Do nothing after parsing (useful for timing)"},
+    {"dump-json", EmitJSON, "Dump all records as machine-readable JSON"},
+    {"print-enums", PrintEnums, "Print enum values for a class"},
+    {"print-sets", PrintSets, "Print expanded sets for testing DAG exprs"},
+};
+
+} // namespace
 
 int main(int argc, char **argv) {
   InitLLVM X(argc, argv);
diff --git a/llvm/utils/TableGen/TableGenBackends.h b/llvm/utils/TableGen/TableGenBackends.h
--- a/llvm/utils/TableGen/TableGenBackends.h
+++ b/llvm/utils/TableGen/TableGenBackends.h
@@ -15,6 +15,11 @@
 #ifndef LLVM_UTILS_TABLEGEN_TABLEGENBACKENDS_H
 #define LLVM_UTILS_TABLEGEN_TABLEGENBACKENDS_H
 
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ManagedStatic.h"
+#include <string>
+
 // A TableGen backend is a function that looks like
 //
 //    EmitFoo(RecordKeeper &RK, raw_ostream &OS /*, anything else you need */ )
@@ -61,41 +66,40 @@
 class raw_ostream;
 class RecordKeeper;
 
-void EmitIntrinsicEnums(RecordKeeper &RK, raw_ostream &OS);
-void EmitIntrinsicImpl(RecordKeeper &RK, raw_ostream &OS);
-void EmitAsmMatcher(RecordKeeper &RK, raw_ostream &OS);
-void EmitAsmWriter(RecordKeeper &RK, raw_ostream &OS);
-void EmitCallingConv(RecordKeeper &RK, raw_ostream &OS);
-void EmitCodeEmitter(RecordKeeper &RK, raw_ostream &OS);
-void EmitDAGISel(RecordKeeper &RK, raw_ostream &OS);
-void EmitDFAPacketizer(RecordKeeper &RK, raw_ostream &OS);
-void EmitDisassembler(RecordKeeper &RK, raw_ostream &OS);
-void EmitFastISel(RecordKeeper &RK, raw_ostream &OS);
-void EmitInstrInfo(RecordKeeper &RK, raw_ostream &OS);
-void EmitInstrDocs(RecordKeeper &RK, raw_ostream &OS);
-void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS);
-void EmitCompressInst(RecordKeeper &RK, raw_ostream &OS);
-void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS);
-void EmitSubtarget(RecordKeeper &RK, raw_ostream &OS);
+namespace TableGen {
+namespace Emitter {
+using FnT = void (*)(RecordKeeper &Records, raw_ostream &OS);
+
+struct OptCreatorT {
+  static void *call();
+};
+
+extern ManagedStatic<cl::opt<FnT>, OptCreatorT> Action;
+
+struct Opt {
+  Opt(StringRef p, FnT fn, StringRef desc, bool isDefault = false) {
+    if (isDefault)
+      Action->setInitialValue(fn);
+    Action->getParser().addLiteralOption(p, fn, desc);
+  }
+};
+
+template <class EmitterC> class OptClass : Opt {
+  static void run(RecordKeeper &RK, raw_ostream &OS) { EmitterC(RK).run(OS); }
+
+public:
+  OptClass(StringRef p, StringRef d) : Opt(p, run, d) {}
+};
+
+} // namespace Emitter
+} // namespace TableGen
+
 void EmitMapTable(RecordKeeper &RK, raw_ostream &OS);
-void EmitOptParser(RecordKeeper &RK, raw_ostream &OS);
-void EmitOptRST(RecordKeeper &RK, raw_ostream &OS);
-void EmitCTags(RecordKeeper &RK, raw_ostream &OS);
-void EmitAttributes(RecordKeeper &RK, raw_ostream &OS);
-void EmitSearchableTables(RecordKeeper &RK, raw_ostream &OS);
-void EmitGlobalISel(RecordKeeper &RK, raw_ostream &OS);
-void EmitGICombiner(RecordKeeper &RK, raw_ostream &OS);
-void EmitX86EVEX2VEXTables(RecordKeeper &RK, raw_ostream &OS);
-void EmitX86FoldTables(RecordKeeper &RK, raw_ostream &OS);
-void EmitX86MnemonicTables(RecordKeeper &RK, raw_ostream &OS);
-void EmitRegisterBank(RecordKeeper &RK, raw_ostream &OS);
-void EmitExegesis(RecordKeeper &RK, raw_ostream &OS);
-void EmitAutomata(RecordKeeper &RK, raw_ostream &OS);
-void EmitDirectivesDecl(RecordKeeper &RK, raw_ostream &OS);
-void EmitDirectivesImpl(RecordKeeper &RK, raw_ostream &OS);
-void EmitDXILOperation(RecordKeeper &RK, raw_ostream &OS);
-void EmitRISCVTargetDef(const RecordKeeper &RK, raw_ostream &OS);
-
-} // End llvm namespace
+
+// Defined in DecoderEmitter.cpp
+void EmitDecoder(RecordKeeper &RK, raw_ostream &OS,
+                 const std::string &PredicateNamespace);
+
+} // namespace llvm
 
 #endif
diff --git a/llvm/utils/TableGen/X86EVEX2VEXTablesEmitter.cpp b/llvm/utils/TableGen/X86EVEX2VEXTablesEmitter.cpp
--- a/llvm/utils/TableGen/X86EVEX2VEXTablesEmitter.cpp
+++ b/llvm/utils/TableGen/X86EVEX2VEXTablesEmitter.cpp
@@ -241,8 +241,5 @@
 }
 } // namespace
 
-namespace llvm {
-void EmitX86EVEX2VEXTables(RecordKeeper &RK, raw_ostream &OS) {
-  X86EVEX2VEXTablesEmitter(RK).run(OS);
-}
-} // namespace llvm
+static TableGen::Emitter::OptClass<X86EVEX2VEXTablesEmitter>
+    X("gen-x86-EVEX2VEX-tables", "Generate X86 EVEX to VEX compress tables");
diff --git a/llvm/utils/TableGen/X86FoldTablesEmitter.cpp b/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
--- a/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
+++ b/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
@@ -165,7 +165,7 @@
   X86FoldTablesEmitter(RecordKeeper &R) : Records(R), Target(R) {}
 
   // run - Generate the 6 X86 memory fold tables.
-  void run(formatted_raw_ostream &OS);
+  void run(raw_ostream &OS);
 
 private:
   // Decides to which table to add the entry with the given instructions.
@@ -512,7 +512,8 @@
   }
 }
 
-void X86FoldTablesEmitter::run(formatted_raw_ostream &OS) {
+void X86FoldTablesEmitter::run(raw_ostream &o) {
+  formatted_raw_ostream OS(o);
   emitSourceFileHeader("X86 fold tables", OS);
 
   // Holds all memory instructions
@@ -611,10 +612,5 @@
   printTable(Table4, "Table4", OS);
 }
 
-namespace llvm {
-
-void EmitX86FoldTables(RecordKeeper &RK, raw_ostream &o) {
-  formatted_raw_ostream OS(o);
-  X86FoldTablesEmitter(RK).run(OS);
-}
-} // namespace llvm
+static TableGen::Emitter::OptClass<X86FoldTablesEmitter>
+    X("gen-x86-fold-tables", "Generate X86 fold tables");
diff --git a/llvm/utils/TableGen/X86MnemonicTables.cpp b/llvm/utils/TableGen/X86MnemonicTables.cpp
--- a/llvm/utils/TableGen/X86MnemonicTables.cpp
+++ b/llvm/utils/TableGen/X86MnemonicTables.cpp
@@ -88,8 +88,5 @@
 
 } // namespace
 
-namespace llvm {
-void EmitX86MnemonicTables(RecordKeeper &RK, raw_ostream &OS) {
-  X86MnemonicTablesEmitter(RK).run(OS);
-}
-} // namespace llvm
+static TableGen::Emitter::OptClass<X86MnemonicTablesEmitter>
+    X("gen-x86-mnemonic-tables", "Generate X86 mnemonic tables");