diff --git a/llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h b/llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h
index 1e07fbe64f7d3..faaff4ad8ee02 100644
--- a/llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h
+++ b/llvm/include/llvm/Support/X86DisassemblerDecoderCommon.h
@@ -18,8 +18,7 @@
 
 #include "llvm/Support/DataTypes.h"
 
-namespace llvm {
-namespace X86Disassembler {
+namespace llvm::X86Disassembler {
 
 #define INSTRUCTIONS_SYM x86DisassemblerInstrSpecifiers
 #define CONTEXTS_SYM x86DisassemblerContexts
@@ -541,7 +540,6 @@ static const unsigned X86_MAX_OPERANDS = 6;
 /// respectively.
 enum DisassemblerMode { MODE_16BIT, MODE_32BIT, MODE_64BIT };
 
-} // namespace X86Disassembler
-} // namespace llvm
+} // namespace llvm::X86Disassembler
 
 #endif
diff --git a/llvm/lib/TableGen/Error.cpp b/llvm/lib/TableGen/Error.cpp
index de0c4c971efeb..3ba2c6c6dddb2 100644
--- a/llvm/lib/TableGen/Error.cpp
+++ b/llvm/lib/TableGen/Error.cpp
@@ -19,10 +19,10 @@
 #include "llvm/TableGen/Record.h"
 #include <cstdlib>
 
-namespace llvm {
+using namespace llvm;
 
-SourceMgr SrcMgr;
-unsigned ErrorsPrinted = 0;
+SourceMgr llvm::SrcMgr;
+unsigned llvm::ErrorsPrinted = 0;
 
 static void PrintMessage(ArrayRef<SMLoc> Locs, SourceMgr::DiagKind Kind,
                          const Twine &Msg) {
@@ -49,118 +49,118 @@ static void PrintMessage(ArrayRef<SMLoc> Locs, SourceMgr::DiagKind Kind,
 
 // Functions to print notes.
 
-void PrintNote(const Twine &Msg) {
-  WithColor::note() << Msg << "\n";
-}
+void llvm::PrintNote(const Twine &Msg) { WithColor::note() << Msg << "\n"; }
 
-void PrintNote(function_ref<void(raw_ostream &OS)> PrintMsg) {
+void llvm::PrintNote(function_ref<void(raw_ostream &OS)> PrintMsg) {
   PrintMsg(WithColor::note());
 }
 
-void PrintNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
+void llvm::PrintNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
   PrintMessage(NoteLoc, SourceMgr::DK_Note, Msg);
 }
 
 // Functions to print fatal notes.
 
-void PrintFatalNote(const Twine &Msg) {
+void llvm::PrintFatalNote(const Twine &Msg) {
   PrintNote(Msg);
   fatal_exit();
 }
 
-void PrintFatalNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
+void llvm::PrintFatalNote(ArrayRef<SMLoc> NoteLoc, const Twine &Msg) {
   PrintNote(NoteLoc, Msg);
   fatal_exit();
 }
 
 // This method takes a Record and uses the source location
 // stored in it.
-void PrintFatalNote(const Record *Rec, const Twine &Msg) {
+void llvm::PrintFatalNote(const Record *Rec, const Twine &Msg) {
   PrintNote(Rec->getLoc(), Msg);
   fatal_exit();
 }
 
 // This method takes a RecordVal and uses the source location
 // stored in it.
-void PrintFatalNote(const RecordVal *RecVal, const Twine &Msg) {
+void llvm::PrintFatalNote(const RecordVal *RecVal, const Twine &Msg) {
   PrintNote(RecVal->getLoc(), Msg);
   fatal_exit();
 }
 
 // Functions to print warnings.
 
-void PrintWarning(const Twine &Msg) { WithColor::warning() << Msg << "\n"; }
+void llvm::PrintWarning(const Twine &Msg) {
+  WithColor::warning() << Msg << "\n";
+}
 
-void PrintWarning(ArrayRef<SMLoc> WarningLoc, const Twine &Msg) {
+void llvm::PrintWarning(ArrayRef<SMLoc> WarningLoc, const Twine &Msg) {
   PrintMessage(WarningLoc, SourceMgr::DK_Warning, Msg);
 }
 
-void PrintWarning(const char *Loc, const Twine &Msg) {
+void llvm::PrintWarning(const char *Loc, const Twine &Msg) {
   SrcMgr.PrintMessage(SMLoc::getFromPointer(Loc), SourceMgr::DK_Warning, Msg);
 }
 
 // Functions to print errors.
 
-void PrintError(const Twine &Msg) { WithColor::error() << Msg << "\n"; }
+void llvm::PrintError(const Twine &Msg) { WithColor::error() << Msg << "\n"; }
 
-void PrintError(function_ref<void(raw_ostream &OS)> PrintMsg) {
+void llvm::PrintError(function_ref<void(raw_ostream &OS)> PrintMsg) {
   PrintMsg(WithColor::error());
 }
 
-void PrintError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
+void llvm::PrintError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
   PrintMessage(ErrorLoc, SourceMgr::DK_Error, Msg);
 }
 
-void PrintError(const char *Loc, const Twine &Msg) {
+void llvm::PrintError(const char *Loc, const Twine &Msg) {
   SrcMgr.PrintMessage(SMLoc::getFromPointer(Loc), SourceMgr::DK_Error, Msg);
 }
 
 // This method takes a Record and uses the source location
 // stored in it.
-void PrintError(const Record *Rec, const Twine &Msg) {
+void llvm::PrintError(const Record *Rec, const Twine &Msg) {
   PrintMessage(Rec->getLoc(), SourceMgr::DK_Error, Msg);
 }
 
 // This method takes a RecordVal and uses the source location
 // stored in it.
-void PrintError(const RecordVal *RecVal, const Twine &Msg) {
+void llvm::PrintError(const RecordVal *RecVal, const Twine &Msg) {
   PrintMessage(RecVal->getLoc(), SourceMgr::DK_Error, Msg);
 }
 
 // Functions to print fatal errors.
 
-void PrintFatalError(const Twine &Msg) {
+void llvm::PrintFatalError(const Twine &Msg) {
   PrintError(Msg);
   fatal_exit();
 }
 
-void PrintFatalError(function_ref<void(raw_ostream &OS)> PrintMsg) {
+void llvm::PrintFatalError(function_ref<void(raw_ostream &OS)> PrintMsg) {
   PrintError(PrintMsg);
   fatal_exit();
 }
 
-void PrintFatalError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
+void llvm::PrintFatalError(ArrayRef<SMLoc> ErrorLoc, const Twine &Msg) {
   PrintError(ErrorLoc, Msg);
   fatal_exit();
 }
 
 // This method takes a Record and uses the source location
 // stored in it.
-void PrintFatalError(const Record *Rec, const Twine &Msg) {
+void llvm::PrintFatalError(const Record *Rec, const Twine &Msg) {
   PrintError(Rec->getLoc(), Msg);
   fatal_exit();
 }
 
 // This method takes a RecordVal and uses the source location
 // stored in it.
-void PrintFatalError(const RecordVal *RecVal, const Twine &Msg) {
+void llvm::PrintFatalError(const RecordVal *RecVal, const Twine &Msg) {
   PrintError(RecVal->getLoc(), Msg);
   fatal_exit();
 }
 
 // Check an assertion: Obtain the condition value and be sure it is true.
 // If not, print a nonfatal error along with the message.
-bool CheckAssert(SMLoc Loc, const Init *Condition, const Init *Message) {
+bool llvm::CheckAssert(SMLoc Loc, const Init *Condition, const Init *Message) {
   auto *CondValue = dyn_cast_or_null<IntInit>(Condition->convertInitializerTo(
       IntRecTy::get(Condition->getRecordKeeper())));
   if (!CondValue) {
@@ -178,11 +178,9 @@ bool CheckAssert(SMLoc Loc, const Init *Condition, const Init *Message) {
 }
 
 // Dump a message to stderr.
-void dumpMessage(SMLoc Loc, const Init *Message) {
+void llvm::dumpMessage(SMLoc Loc, const Init *Message) {
   if (auto *MessageInit = dyn_cast<StringInit>(Message))
     PrintNote(Loc, MessageInit->getValue());
   else
     PrintError(Loc, "dump value is not of type string");
 }
-
-} // end namespace llvm
diff --git a/llvm/lib/TableGen/Main.cpp b/llvm/lib/TableGen/Main.cpp
index f545706d6fe30..42043f70768c5 100644
--- a/llvm/lib/TableGen/Main.cpp
+++ b/llvm/lib/TableGen/Main.cpp
@@ -64,14 +64,12 @@ WriteIfChanged("write-if-changed", cl::desc("Only write output if it changed"));
 static cl::opt<bool>
 TimePhases("time-phases", cl::desc("Time phases of parser and backend"));
 
-namespace llvm {
-cl::opt<bool> EmitLongStrLiterals(
+cl::opt<bool> llvm::EmitLongStrLiterals(
     "long-string-literals",
     cl::desc("when emitting large string tables, prefer string literals over "
              "comma-separated char literals. This can be a readability and "
              "compile-time performance win, but upsets some compilers"),
     cl::Hidden, cl::init(true));
-} // end namespace llvm
 
 static cl::opt<bool> NoWarnOnUnusedTemplateArgs(
     "no-warn-on-unused-template-args",
diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index 051a896cfd1b4..2ea3a24bb8eb2 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -46,8 +46,7 @@ using namespace llvm;
 //    Context
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-namespace detail {
+namespace llvm::detail {
 /// This class represents the internal implementation of the RecordKeeper.
 /// It contains all of the contextual static state of the Record classes. It is
 /// kept out-of-line to simplify dependencies, and also make it easier for
@@ -100,8 +99,7 @@ struct RecordKeeperImpl {
 
   void dumpAllocationStats(raw_ostream &OS) const;
 };
-} // namespace detail
-} // namespace llvm
+} // namespace llvm::detail
 
 void detail::RecordKeeperImpl::dumpAllocationStats(raw_ostream &OS) const {
   // Dump memory allocation related stats.
diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index f928ded16186f..3d31d8e2717b1 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -31,8 +31,6 @@ using namespace llvm;
 // Support Code for the Semantic Actions.
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-
 RecordsEntry::RecordsEntry(std::unique_ptr<Record> Rec) : Rec(std::move(Rec)) {}
 RecordsEntry::RecordsEntry(std::unique_ptr<ForeachLoop> Loop)
     : Loop(std::move(Loop)) {}
@@ -41,6 +39,7 @@ RecordsEntry::RecordsEntry(std::unique_ptr<Record::AssertionInfo> Assertion)
 RecordsEntry::RecordsEntry(std::unique_ptr<Record::DumpInfo> Dump)
     : Dump(std::move(Dump)) {}
 
+namespace llvm {
 struct SubClassReference {
   SMRange RefRange;
   const Record *Rec = nullptr;
@@ -61,6 +60,7 @@ struct SubMultiClassReference {
   bool isInvalid() const { return MC == nullptr; }
   void dump() const;
 };
+} // end namespace llvm
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void SubMultiClassReference::dump() const {
@@ -74,8 +74,6 @@ LLVM_DUMP_METHOD void SubMultiClassReference::dump() const {
 }
 #endif
 
-} // end namespace llvm
-
 static bool checkBitsConcrete(Record &R, const RecordVal &RV) {
   const auto *BV = cast<BitsInit>(RV.getValue());
   for (unsigned i = 0, e = BV->getNumBits(); i != e; ++i) {
diff --git a/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp
index 75bea77faba42..8076ce2486f56 100644
--- a/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/Common/CodeGenDAGPatterns.cpp
@@ -246,16 +246,14 @@ bool TypeSetByHwMode::operator==(const TypeSetByHwMode &VTS) const {
   return true;
 }
 
-namespace llvm {
-raw_ostream &operator<<(raw_ostream &OS, const MachineValueTypeSet &T) {
+raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineValueTypeSet &T) {
   T.writeToStream(OS);
   return OS;
 }
-raw_ostream &operator<<(raw_ostream &OS, const TypeSetByHwMode &T) {
+raw_ostream &llvm::operator<<(raw_ostream &OS, const TypeSetByHwMode &T) {
   T.writeToStream(OS);
   return OS;
 }
-} // namespace llvm
 
 LLVM_DUMP_METHOD
 void TypeSetByHwMode::dump() const { dbgs() << *this << '\n'; }
diff --git a/llvm/utils/TableGen/Common/CodeGenRegisters.cpp b/llvm/utils/TableGen/Common/CodeGenRegisters.cpp
index 294f3af5a0055..8d0ec9abd23ae 100644
--- a/llvm/utils/TableGen/Common/CodeGenRegisters.cpp
+++ b/llvm/utils/TableGen/Common/CodeGenRegisters.cpp
@@ -857,17 +857,6 @@ unsigned CodeGenRegisterClass::getWeight(const CodeGenRegBank &RegBank) const {
   return (*Members.begin())->getWeight(RegBank);
 }
 
-namespace llvm {
-
-raw_ostream &operator<<(raw_ostream &OS, const CodeGenRegisterClass::Key &K) {
-  OS << "{ " << K.RSI;
-  for (const auto R : *K.Members)
-    OS << ", " << R->getName();
-  return OS << " }";
-}
-
-} // end namespace llvm
-
 // This is a simple lexicographical order that can be used to search for sets.
 // It is not the same as the topological order provided by TopoOrderRC.
 bool CodeGenRegisterClass::Key::operator<(
diff --git a/llvm/utils/TableGen/Common/InfoByHwMode.cpp b/llvm/utils/TableGen/Common/InfoByHwMode.cpp
index a6e2fc415f350..4c8197dc60c14 100644
--- a/llvm/utils/TableGen/Common/InfoByHwMode.cpp
+++ b/llvm/utils/TableGen/Common/InfoByHwMode.cpp
@@ -227,19 +227,17 @@ EncodingInfoByHwMode::EncodingInfoByHwMode(const Record *R,
   }
 }
 
-namespace llvm {
-raw_ostream &operator<<(raw_ostream &OS, const ValueTypeByHwMode &T) {
+raw_ostream &llvm::operator<<(raw_ostream &OS, const ValueTypeByHwMode &T) {
   T.writeToStream(OS);
   return OS;
 }
 
-raw_ostream &operator<<(raw_ostream &OS, const RegSizeInfo &T) {
+raw_ostream &llvm::operator<<(raw_ostream &OS, const RegSizeInfo &T) {
   T.writeToStream(OS);
   return OS;
 }
 
-raw_ostream &operator<<(raw_ostream &OS, const RegSizeInfoByHwMode &T) {
+raw_ostream &llvm::operator<<(raw_ostream &OS, const RegSizeInfoByHwMode &T) {
   T.writeToStream(OS);
   return OS;
 }
-} // namespace llvm
diff --git a/llvm/utils/TableGen/Common/PredicateExpander.cpp b/llvm/utils/TableGen/Common/PredicateExpander.cpp
index 09d953801600d..03252ed465b75 100644
--- a/llvm/utils/TableGen/Common/PredicateExpander.cpp
+++ b/llvm/utils/TableGen/Common/PredicateExpander.cpp
@@ -14,7 +14,7 @@
 #include "CodeGenSchedule.h" // Definition of STIPredicateFunction.
 #include "llvm/TableGen/Record.h"
 
-namespace llvm {
+using namespace llvm;
 
 void PredicateExpander::expandTrue(raw_ostream &OS) { OS << "true"; }
 void PredicateExpander::expandFalse(raw_ostream &OS) { OS << "false"; }
@@ -553,5 +553,3 @@ void STIPredicateExpander::expandSTIPredicate(raw_ostream &OS,
     expandEpilogue(OS, Fn);
   }
 }
-
-} // namespace llvm
diff --git a/llvm/utils/TableGen/DXILEmitter.cpp b/llvm/utils/TableGen/DXILEmitter.cpp
index 09ce9f3027410..94719598dfd58 100644
--- a/llvm/utils/TableGen/DXILEmitter.cpp
+++ b/llvm/utils/TableGen/DXILEmitter.cpp
@@ -37,15 +37,6 @@ struct DXILIntrinsicSelect {
   SmallVector<const Record *> ArgSelectRecords;
 };
 
-static StringRef StripIntrinArgSelectTypePrefix(StringRef Type) {
-  StringRef Prefix = "IntrinArgSelect_";
-  if (!Type.starts_with(Prefix)) {
-    PrintFatalError("IntrinArgSelectType definintion must be prefixed with "
-                    "'IntrinArgSelect_'");
-  }
-  return Type.substr(Prefix.size());
-}
-
 struct DXILOperationDesc {
   std::string OpName; // name of DXIL operation
   int OpCode;         // ID of DXIL operation
@@ -66,6 +57,15 @@ struct DXILOperationDesc {
 };
 } // end anonymous namespace
 
+static StringRef stripIntrinArgSelectTypePrefix(StringRef Type) {
+  StringRef Prefix = "IntrinArgSelect_";
+  if (!Type.starts_with(Prefix)) {
+    PrintFatalError("IntrinArgSelectType definintion must be prefixed with "
+                    "'IntrinArgSelect_'");
+  }
+  return Type.substr(Prefix.size());
+}
+
 /// In-place sort TableGen records of class with a field
 ///    Version dxil_version
 /// in the ascending version order.
@@ -449,7 +449,7 @@ static void emitDXILIntrinsicMap(ArrayRef<DXILOperationDesc> Ops,
             ArgSelect->getValueAsDef("type")->getNameInitAsString();
         int Value = ArgSelect->getValueAsInt("value");
         OS << "(IntrinArgSelect{"
-           << "IntrinArgSelect::Type::" << StripIntrinArgSelectTypePrefix(Type)
+           << "IntrinArgSelect::Type::" << stripIntrinArgSelectTypePrefix(Type)
            << "," << Value << "}), ";
       }
       OS << ")\n";
@@ -466,7 +466,7 @@ static void emitDXILIntrinsicArgSelectTypes(const RecordKeeper &Records,
   OS << "#ifdef DXIL_OP_INTRINSIC_ARG_SELECT_TYPE\n";
   for (const Record *Records :
        Records.getAllDerivedDefinitions("IntrinArgSelectType")) {
-    StringRef StrippedName = StripIntrinArgSelectTypePrefix(Records->getName());
+    StringRef StrippedName = stripIntrinArgSelectTypePrefix(Records->getName());
     OS << "DXIL_OP_INTRINSIC_ARG_SELECT_TYPE(" << StrippedName << ")\n";
   }
   OS << "#undef DXIL_OP_INTRINSIC_ARG_SELECT_TYPE\n";
diff --git a/llvm/utils/TableGen/DecoderEmitter.cpp b/llvm/utils/TableGen/DecoderEmitter.cpp
index 961dc2815f6b9..5d41b7dc3c311 100644
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -194,10 +194,6 @@ class DecoderEmitter {
   void parseInstructionEncodings();
 };
 
-} // end anonymous namespace
-
-namespace {
-
 struct EncodingIsland {
   unsigned StartBit;
   unsigned NumBits;
diff --git a/llvm/utils/TableGen/ExegesisEmitter.cpp b/llvm/utils/TableGen/ExegesisEmitter.cpp
index 1b4b0729a5fcc..bd69919bb462e 100644
--- a/llvm/utils/TableGen/ExegesisEmitter.cpp
+++ b/llvm/utils/TableGen/ExegesisEmitter.cpp
@@ -58,6 +58,14 @@ class ExegesisEmitter {
   const std::map<llvm::StringRef, unsigned> PfmCounterNameTable;
 };
 
+struct ValidationCounterInfo {
+  int64_t EventNumber;
+  StringRef EventName;
+  unsigned PfmCounterID;
+};
+
+} // namespace
+
 static std::map<llvm::StringRef, unsigned>
 collectPfmCounters(const RecordKeeper &Records) {
   std::map<llvm::StringRef, unsigned> PfmCounterNameTable;
@@ -106,14 +114,8 @@ ExegesisEmitter::ExegesisEmitter(const RecordKeeper &RK)
   Target = Targets[0]->getName().str();
 }
 
-struct ValidationCounterInfo {
-  int64_t EventNumber;
-  StringRef EventName;
-  unsigned PfmCounterID;
-};
-
-bool EventNumberLess(const ValidationCounterInfo &LHS,
-                     const ValidationCounterInfo &RHS) {
+static bool EventNumberLess(const ValidationCounterInfo &LHS,
+                            const ValidationCounterInfo &RHS) {
   return LHS.EventNumber < RHS.EventNumber;
 }
 
@@ -221,7 +223,7 @@ void ExegesisEmitter::emitPfmCounters(raw_ostream &OS) const {
     emitPfmCountersInfo(*Def, IssueCountersTableOffset, OS);
 
   OS << "\n";
-} // namespace
+}
 
 void ExegesisEmitter::emitPfmCountersLookupTable(raw_ostream &OS) const {
   std::vector<const Record *> Bindings =
@@ -249,7 +251,5 @@ void ExegesisEmitter::run(raw_ostream &OS) const {
   emitPfmCountersLookupTable(OS);
 }
 
-} // end anonymous namespace
-
 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
index 694d89a5ada3c..dba8bde54ff4d 100644
--- a/llvm/utils/TableGen/FastISelEmitter.cpp
+++ b/llvm/utils/TableGen/FastISelEmitter.cpp
@@ -52,11 +52,9 @@ struct InstructionMemo {
   InstructionMemo(const InstructionMemo &Other) = delete;
   InstructionMemo(InstructionMemo &&Other) = default;
 };
-} // End anonymous namespace
 
 /// ImmPredicateSet - This uniques predicates (represented as a string) and
 /// gives them unique (small) integer ID's that start at 0.
-namespace {
 class ImmPredicateSet {
   DenseMap<TreePattern *, unsigned> ImmIDs;
   std::vector<TreePredicateFn> PredsByName;
@@ -77,12 +75,10 @@ class ImmPredicateSet {
   iterator begin() const { return PredsByName.begin(); }
   iterator end() const { return PredsByName.end(); }
 };
-} // End anonymous namespace
 
 /// OperandsSignature - This class holds a description of a list of operand
 /// types. It has utility methods for emitting text based on the operands.
 ///
-namespace {
 struct OperandsSignature {
   class OpKind {
     enum { OK_Reg, OK_FP, OK_Imm, OK_Invalid = -1 };
@@ -366,9 +362,7 @@ struct OperandsSignature {
       Opnd.printManglingSuffix(OS, ImmPredicates, StripImmCodes);
   }
 };
-} // End anonymous namespace
 
-namespace {
 class FastISelMap {
   // A multimap is needed instead of a "plain" map because the key is
   // the instruction's complexity (an int) and they are not unique.
diff --git a/llvm/utils/TableGen/X86DisassemblerShared.h b/llvm/utils/TableGen/X86DisassemblerShared.h
index f60fd477788a5..d5f936dabab6a 100644
--- a/llvm/utils/TableGen/X86DisassemblerShared.h
+++ b/llvm/utils/TableGen/X86DisassemblerShared.h
@@ -14,6 +14,8 @@
 
 #include "llvm/Support/X86DisassemblerDecoderCommon.h"
 
+namespace llvm::X86Disassembler {
+
 struct InstructionSpecifier {
   llvm::X86Disassembler::OperandSpecifier
       operands[llvm::X86Disassembler::X86_MAX_OPERANDS];
@@ -52,4 +54,6 @@ struct ContextDecision {
   ContextDecision() { memset(opcodeDecisions, 0, sizeof(opcodeDecisions)); }
 };
 
+} // namespace llvm::X86Disassembler
+
 #endif
diff --git a/llvm/utils/TableGen/X86FoldTablesEmitter.cpp b/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
index 1e1e4ab650030..6f523b5a197d3 100644
--- a/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
+++ b/llvm/utils/TableGen/X86FoldTablesEmitter.cpp
@@ -30,22 +30,23 @@ struct ManualMapEntry {
   const char *MemInstStr;
   uint16_t Strategy;
 };
+} // namespace
 
 // List of instructions requiring explicitly aligned memory.
-const char *ExplicitAlign[] = {"MOVDQA",  "MOVAPS",  "MOVAPD",  "MOVNTPS",
-                               "MOVNTPD", "MOVNTDQ", "MOVNTDQA"};
+static constexpr const char *ExplicitAlign[] = {
+    "MOVDQA", "MOVAPS", "MOVAPD", "MOVNTPS", "MOVNTPD", "MOVNTDQ", "MOVNTDQA"};
 
 // List of instructions NOT requiring explicit memory alignment.
-const char *ExplicitUnalign[] = {"MOVDQU",    "MOVUPS",    "MOVUPD",
-                                 "PCMPESTRM", "PCMPESTRI", "PCMPISTRM",
-                                 "PCMPISTRI"};
+static constexpr const char *ExplicitUnalign[] = {
+    "MOVDQU",    "MOVUPS",    "MOVUPD",   "PCMPESTRM",
+    "PCMPESTRI", "PCMPISTRM", "PCMPISTRI"};
 
-const ManualMapEntry ManualMapSet[] = {
+static const ManualMapEntry ManualMapSet[] = {
 #define ENTRY(REG, MEM, FLAGS) {#REG, #MEM, FLAGS},
 #include "X86ManualFoldTables.def"
 };
 
-const std::set<StringRef> NoFoldSet = {
+static const std::set<StringRef> NoFoldSet = {
 #define NOFOLD(INSN) #INSN,
 #include "X86ManualFoldTables.def"
 };
@@ -62,6 +63,7 @@ static bool isExplicitUnalign(const CodeGenInstruction *Inst) {
   });
 }
 
+namespace {
 class X86FoldTablesEmitter {
   const RecordKeeper &Records;
   const CodeGenTarget Target;
@@ -230,6 +232,7 @@ class X86FoldTablesEmitter {
     OS << "};\n\n";
   }
 };
+} // namespace
 
 // Return true if one of the instruction's operands is a RST register class
 static bool hasRSTRegClass(const CodeGenInstruction *Inst) {
@@ -318,6 +321,7 @@ static bool isNOREXRegClass(const Record *Op) {
 
 // Function object - Operator() returns true if the given Reg instruction
 // matches the Mem instruction of this object.
+namespace {
 class IsMatch {
   const CodeGenInstruction *MemInst;
   const X86Disassembler::RecognizableInstrBase MemRI;
diff --git a/llvm/utils/TableGen/X86InstrMappingEmitter.cpp b/llvm/utils/TableGen/X86InstrMappingEmitter.cpp
index be5e2a73e8d43..2745ba72ba624 100644
--- a/llvm/utils/TableGen/X86InstrMappingEmitter.cpp
+++ b/llvm/utils/TableGen/X86InstrMappingEmitter.cpp
@@ -66,6 +66,7 @@ class X86InstrMappingEmitter {
   void printTable(ArrayRef<Entry> Table, StringRef Name, StringRef Macro,
                   raw_ostream &OS);
 };
+} // namespace
 
 void X86InstrMappingEmitter::printClassDef(raw_ostream &OS) {
   OS << "struct X86TableEntry {\n"
@@ -106,6 +107,7 @@ void X86InstrMappingEmitter::printTable(ArrayRef<Entry> Table, StringRef Name,
   printMacroEnd(Macro, OS);
 }
 
+namespace {
 class IsMatch {
   const CodeGenInstruction *OldInst;
 
@@ -146,6 +148,7 @@ class IsMatch {
     return true;
   }
 };
+} // namespace
 
 static bool isInteresting(const Record *Rec) {
   // _REV instruction should not appear before encoding optimization
@@ -368,7 +371,6 @@ void X86InstrMappingEmitter::run(raw_ostream &OS) {
   emitND2NonNDTable(Insts, OS);
   emitSSE2AVXTable(Insts, OS);
 }
-} // namespace
 
 static TableGen::Emitter::OptClass<X86InstrMappingEmitter>
     X("gen-x86-instr-mapping", "Generate X86 instruction mapping");
diff --git a/llvm/utils/TableGen/X86MnemonicTables.cpp b/llvm/utils/TableGen/X86MnemonicTables.cpp
index 85bd4df0d4362..7851919bd7387 100644
--- a/llvm/utils/TableGen/X86MnemonicTables.cpp
+++ b/llvm/utils/TableGen/X86MnemonicTables.cpp
@@ -30,6 +30,7 @@ class X86MnemonicTablesEmitter {
   // Output X86 mnemonic tables.
   void run(raw_ostream &OS);
 };
+} // namespace
 
 void X86MnemonicTablesEmitter::run(raw_ostream &OS) {
   emitSourceFileHeader("X86 Mnemonic tables", OS);
@@ -83,7 +84,5 @@ void X86MnemonicTablesEmitter::run(raw_ostream &OS) {
   OS << "} // end namespace X86\n} // end namespace llvm";
 }
 
-} // namespace
-
 static TableGen::Emitter::OptClass<X86MnemonicTablesEmitter>
     X("gen-x86-mnemonic-tables", "Generate X86 mnemonic tables");
diff --git a/llvm/utils/TableGen/X86ModRMFilters.h b/llvm/utils/TableGen/X86ModRMFilters.h
index b579f229379bb..7bf111ffa1d50 100644
--- a/llvm/utils/TableGen/X86ModRMFilters.h
+++ b/llvm/utils/TableGen/X86ModRMFilters.h
@@ -19,9 +19,7 @@
 
 #include <cstdint>
 
-namespace llvm {
-
-namespace X86Disassembler {
+namespace llvm::X86Disassembler {
 
 /// ModRMFilter - Abstract base class for clases that recognize patterns in
 ///   ModR/M bytes.
@@ -135,8 +133,6 @@ class ExactFilter : public ModRMFilter {
   bool accepts(uint8_t modRM) const override { return (ModRM == modRM); }
 };
 
-} // namespace X86Disassembler
-
-} // namespace llvm
+} // namespace llvm::X86Disassembler
 
 #endif
diff --git a/llvm/utils/TableGen/X86RecognizableInstr.h b/llvm/utils/TableGen/X86RecognizableInstr.h
index b74e74dd3f6e7..52f95383b6fb4 100644
--- a/llvm/utils/TableGen/X86RecognizableInstr.h
+++ b/llvm/utils/TableGen/X86RecognizableInstr.h
@@ -22,8 +22,6 @@
 #include <string>
 #include <vector>
 
-struct InstructionSpecifier;
-
 namespace llvm {
 class Record;
 #define X86_INSTR_MRM_MAPPING                                                  \
@@ -179,6 +177,8 @@ enum { ExplicitREX2 = 1, ExplicitEVEX = 3 };
 
 namespace X86Disassembler {
 class DisassemblerTables;
+struct InstructionSpecifier;
+
 /// Extract common fields of a single X86 instruction from a CodeGenInstruction
 struct RecognizableInstrBase {
   /// The OpPrefix field from the record