diff --git a/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h b/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h
--- a/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h
+++ b/llvm/include/llvm/Analysis/InstructionPrecedenceTracking.h
@@ -110,7 +110,7 @@
     return isPreceededBySpecialInstruction(Insn);
   }
 
-  virtual bool isSpecialInstruction(const Instruction *Insn) const;
+  bool isSpecialInstruction(const Instruction *Insn) const override;
 };
 
 class MemoryWriteTracking : public InstructionPrecedenceTracking {
@@ -133,7 +133,7 @@
     return isPreceededBySpecialInstruction(Insn);
   }
 
-  virtual bool isSpecialInstruction(const Instruction *Insn) const;
+  bool isSpecialInstruction(const Instruction *Insn) const override;
 };
 
 } // llvm
diff --git a/llvm/include/llvm/Analysis/MustExecute.h b/llvm/include/llvm/Analysis/MustExecute.h
--- a/llvm/include/llvm/Analysis/MustExecute.h
+++ b/llvm/include/llvm/Analysis/MustExecute.h
@@ -111,17 +111,15 @@
   bool HeaderMayThrow = false; // Same as previous, but specific to loop header
 
 public:
-  virtual bool blockMayThrow(const BasicBlock *BB) const;
+  bool blockMayThrow(const BasicBlock *BB) const override;
 
-  virtual bool anyBlockMayThrow() const;
+  bool anyBlockMayThrow() const override;
 
-  virtual void computeLoopSafetyInfo(const Loop *CurLoop);
+  void computeLoopSafetyInfo(const Loop *CurLoop) override;
 
-  virtual bool isGuaranteedToExecute(const Instruction &Inst,
-                                     const DominatorTree *DT,
-                                     const Loop *CurLoop) const;
-
-  virtual ~SimpleLoopSafetyInfo() {};
+  bool isGuaranteedToExecute(const Instruction &Inst,
+                             const DominatorTree *DT,
+                             const Loop *CurLoop) const override;
 };
 
 /// This implementation of LoopSafetyInfo use ImplicitControlFlowTracking to
@@ -138,15 +136,15 @@
   mutable MemoryWriteTracking MW;
 
 public:
-  virtual bool blockMayThrow(const BasicBlock *BB) const;
+  bool blockMayThrow(const BasicBlock *BB) const override;
 
-  virtual bool anyBlockMayThrow() const;
+  bool anyBlockMayThrow() const override;
 
-  virtual void computeLoopSafetyInfo(const Loop *CurLoop);
+  void computeLoopSafetyInfo(const Loop *CurLoop) override;
 
-  virtual bool isGuaranteedToExecute(const Instruction &Inst,
-                                     const DominatorTree *DT,
-                                     const Loop *CurLoop) const;
+  bool isGuaranteedToExecute(const Instruction &Inst,
+                             const DominatorTree *DT,
+                             const Loop *CurLoop) const override;
 
   /// Returns true if we could not execute a memory-modifying instruction before
   /// we enter \p BB under assumption that \p CurLoop is entered.
@@ -167,8 +165,6 @@
   /// from its block. It will make all cache updates to keep it correct after
   /// this removal.
   void removeInstruction(const Instruction *Inst);
-
-  virtual ~ICFLoopSafetyInfo() {};
 };
 
 bool mayContainIrreducibleControl(const Function &F, const LoopInfo *LI);
diff --git a/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h b/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
--- a/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
+++ b/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
@@ -313,8 +313,8 @@
   explicit PrimitiveTypeNode(PrimitiveKind K)
       : TypeNode(NodeKind::PrimitiveType), PrimKind(K) {}
 
-  void outputPre(OutputStream &OS, OutputFlags Flags) const;
-  void outputPost(OutputStream &OS, OutputFlags Flags) const {}
+  void outputPre(OutputStream &OS, OutputFlags Flags) const override;
+  void outputPost(OutputStream &OS, OutputFlags Flags) const override {}
 
   PrimitiveKind PrimKind;
 };
@@ -474,8 +474,8 @@
 struct TagTypeNode : public TypeNode {
   explicit TagTypeNode(TagKind Tag) : TypeNode(NodeKind::TagType), Tag(Tag) {}
 
-  void outputPre(OutputStream &OS, OutputFlags Flags) const;
-  void outputPost(OutputStream &OS, OutputFlags Flags) const;
+  void outputPre(OutputStream &OS, OutputFlags Flags) const override;
+  void outputPost(OutputStream &OS, OutputFlags Flags) const override;
 
   QualifiedNameNode *QualifiedName = nullptr;
   TagKind Tag;
@@ -484,8 +484,8 @@
 struct ArrayTypeNode : public TypeNode {
   ArrayTypeNode() : TypeNode(NodeKind::ArrayType) {}
 
-  void outputPre(OutputStream &OS, OutputFlags Flags) const;
-  void outputPost(OutputStream &OS, OutputFlags Flags) const;
+  void outputPre(OutputStream &OS, OutputFlags Flags) const override;
+  void outputPost(OutputStream &OS, OutputFlags Flags) const override;
 
   void outputDimensionsImpl(OutputStream &OS, OutputFlags Flags) const;
   void outputOneDimension(OutputStream &OS, OutputFlags Flags, Node *N) const;
diff --git a/llvm/include/llvm/IR/DiagnosticInfo.h b/llvm/include/llvm/IR/DiagnosticInfo.h
--- a/llvm/include/llvm/IR/DiagnosticInfo.h
+++ b/llvm/include/llvm/IR/DiagnosticInfo.h
@@ -213,7 +213,7 @@
 };
 
 class DiagnosticInfoStackSize : public DiagnosticInfoResourceLimit {
-  virtual void anchor() override;
+  void anchor() override;
 public:
   DiagnosticInfoStackSize(const Function &Fn, uint64_t StackSize,
                           DiagnosticSeverity Severity = DS_Warning,
@@ -364,7 +364,7 @@
 
 /// Common features for diagnostics with an associated location.
 class DiagnosticInfoWithLocationBase : public DiagnosticInfo {
-  virtual void anchor() override;
+  void anchor() override;
 public:
   /// \p Fn is the function where the diagnostic is being emitted. \p Loc is
   /// the location information to use in the diagnostic.
@@ -611,7 +611,7 @@
 /// Common features for diagnostics dealing with optimization remarks
 /// that are used by IR passes.
 class DiagnosticInfoIROptimization : public DiagnosticInfoOptimizationBase {
-  virtual void anchor() override;
+  void anchor() override;
 public:
   /// \p PassName is the name of the pass emitting this diagnostic. \p
   /// RemarkName is a textual identifier for the remark (single-word,
@@ -832,7 +832,7 @@
 /// Diagnostic information for optimization analysis remarks related to
 /// floating-point non-commutativity.
 class OptimizationRemarkAnalysisFPCommute : public OptimizationRemarkAnalysis {
-  virtual void anchor();
+  void anchor() override;
 public:
   /// \p PassName is the name of the pass emitting this diagnostic. If this name
   /// matches the regular expression given in -Rpass-analysis=, then the
@@ -874,7 +874,7 @@
 /// Diagnostic information for optimization analysis remarks related to
 /// pointer aliasing.
 class OptimizationRemarkAnalysisAliasing : public OptimizationRemarkAnalysis {
-  virtual void anchor();
+  void anchor() override;
 public:
   /// \p PassName is the name of the pass emitting this diagnostic. If this name
   /// matches the regular expression given in -Rpass-analysis=, then the
diff --git a/llvm/include/llvm/MC/MCELFObjectWriter.h b/llvm/include/llvm/MC/MCELFObjectWriter.h
--- a/llvm/include/llvm/MC/MCELFObjectWriter.h
+++ b/llvm/include/llvm/MC/MCELFObjectWriter.h
@@ -65,7 +65,7 @@
 public:
   virtual ~MCELFObjectTargetWriter() = default;
 
-  virtual Triple::ObjectFormatType getFormat() const { return Triple::ELF; }
+  Triple::ObjectFormatType getFormat() const override { return Triple::ELF; }
   static bool classof(const MCObjectTargetWriter *W) {
     return W->getFormat() == Triple::ELF;
   }
diff --git a/llvm/include/llvm/MC/MCMachObjectWriter.h b/llvm/include/llvm/MC/MCMachObjectWriter.h
--- a/llvm/include/llvm/MC/MCMachObjectWriter.h
+++ b/llvm/include/llvm/MC/MCMachObjectWriter.h
@@ -45,7 +45,7 @@
 public:
   virtual ~MCMachObjectTargetWriter();
 
-  virtual Triple::ObjectFormatType getFormat() const { return Triple::MachO; }
+  Triple::ObjectFormatType getFormat() const override { return Triple::MachO; }
   static bool classof(const MCObjectTargetWriter *W) {
     return W->getFormat() == Triple::MachO;
   }
diff --git a/llvm/include/llvm/MC/MCWasmObjectWriter.h b/llvm/include/llvm/MC/MCWasmObjectWriter.h
--- a/llvm/include/llvm/MC/MCWasmObjectWriter.h
+++ b/llvm/include/llvm/MC/MCWasmObjectWriter.h
@@ -28,7 +28,7 @@
 public:
   virtual ~MCWasmObjectTargetWriter();
 
-  virtual Triple::ObjectFormatType getFormat() const { return Triple::Wasm; }
+  Triple::ObjectFormatType getFormat() const override { return Triple::Wasm; }
   static bool classof(const MCObjectTargetWriter *W) {
     return W->getFormat() == Triple::Wasm;
   }
diff --git a/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h b/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
--- a/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
+++ b/llvm/include/llvm/MC/MCWinCOFFObjectWriter.h
@@ -31,7 +31,7 @@
   public:
     virtual ~MCWinCOFFObjectTargetWriter() = default;
 
-    virtual Triple::ObjectFormatType getFormat() const { return Triple::COFF; }
+    Triple::ObjectFormatType getFormat() const override { return Triple::COFF; }
     static bool classof(const MCObjectTargetWriter *W) {
       return W->getFormat() == Triple::COFF;
     }
diff --git a/llvm/include/llvm/Object/Error.h b/llvm/include/llvm/Object/Error.h
--- a/llvm/include/llvm/Object/Error.h
+++ b/llvm/include/llvm/Object/Error.h
@@ -51,7 +51,7 @@
 /// Currently inherits from ECError for easy interoperability with
 /// std::error_code, but this will be removed in the future.
 class BinaryError : public ErrorInfo<BinaryError, ECError> {
-  virtual void anchor();
+  void anchor() override;
 public:
   static char ID;
   BinaryError() {
diff --git a/llvm/include/llvm/Support/FormatAdapters.h b/llvm/include/llvm/Support/FormatAdapters.h
--- a/llvm/include/llvm/Support/FormatAdapters.h
+++ b/llvm/include/llvm/Support/FormatAdapters.h
@@ -34,7 +34,7 @@
       : FormatAdapter<T>(std::forward<T>(Item)), Where(Where), Amount(Amount),
         Fill(Fill) {}
 
-  void format(llvm::raw_ostream &Stream, StringRef Style) {
+  void format(llvm::raw_ostream &Stream, StringRef Style) override {
     auto Adapter = detail::build_format_adapter(std::forward<T>(this->Item));
     FmtAlign(Adapter, Where, Amount, Fill).format(Stream, Style);
   }
@@ -48,7 +48,7 @@
   PadAdapter(T &&Item, size_t Left, size_t Right)
       : FormatAdapter<T>(std::forward<T>(Item)), Left(Left), Right(Right) {}
 
-  void format(llvm::raw_ostream &Stream, StringRef Style) {
+  void format(llvm::raw_ostream &Stream, StringRef Style) override {
     auto Adapter = detail::build_format_adapter(std::forward<T>(this->Item));
     Stream.indent(Left);
     Adapter.format(Stream, Style);
@@ -63,7 +63,7 @@
   RepeatAdapter(T &&Item, size_t Count)
       : FormatAdapter<T>(std::forward<T>(Item)), Count(Count) {}
 
-  void format(llvm::raw_ostream &Stream, StringRef Style) {
+  void format(llvm::raw_ostream &Stream, StringRef Style) override {
     auto Adapter = detail::build_format_adapter(std::forward<T>(this->Item));
     for (size_t I = 0; I < Count; ++I) {
       Adapter.format(Stream, Style);
@@ -76,7 +76,9 @@
   ErrorAdapter(Error &&Item) : FormatAdapter(std::move(Item)) {}
   ErrorAdapter(ErrorAdapter &&) = default;
   ~ErrorAdapter() { consumeError(std::move(Item)); }
-  void format(llvm::raw_ostream &Stream, StringRef Style) { Stream << Item; }
+  void format(llvm::raw_ostream &Stream, StringRef Style) override {
+    Stream << Item;
+  }
 };
 }
 
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -330,11 +330,11 @@
   LazyValueInfoAnnotatedWriter(LazyValueInfoImpl *L, DominatorTree &DTree)
       : LVIImpl(L), DT(DTree) {}
 
-  virtual void emitBasicBlockStartAnnot(const BasicBlock *BB,
-                                        formatted_raw_ostream &OS);
+  void emitBasicBlockStartAnnot(const BasicBlock *BB,
+                                formatted_raw_ostream &OS) override;
 
-  virtual void emitInstructionAnnot(const Instruction *I,
-                                    formatted_raw_ostream &OS);
+  void emitInstructionAnnot(const Instruction *I,
+                            formatted_raw_ostream &OS) override;
 };
 }
 namespace {
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -101,21 +101,21 @@
   CVMCAdapter(MCStreamer &OS, TypeCollection &TypeTable)
       : OS(&OS), TypeTable(TypeTable) {}
 
-  void emitBytes(StringRef Data) { OS->emitBytes(Data); }
+  void emitBytes(StringRef Data) override { OS->emitBytes(Data); }
 
-  void emitIntValue(uint64_t Value, unsigned Size) {
+  void emitIntValue(uint64_t Value, unsigned Size) override {
     OS->emitIntValueInHex(Value, Size);
   }
 
-  void emitBinaryData(StringRef Data) { OS->emitBinaryData(Data); }
+  void emitBinaryData(StringRef Data) override { OS->emitBinaryData(Data); }
 
-  void AddComment(const Twine &T) { OS->AddComment(T); }
+  void AddComment(const Twine &T) override { OS->AddComment(T); }
 
-  void AddRawComment(const Twine &T) { OS->emitRawComment(T); }
+  void AddRawComment(const Twine &T) override { OS->emitRawComment(T); }
 
-  bool isVerboseAsm() { return OS->isVerboseAsm(); }
+  bool isVerboseAsm() override { return OS->isVerboseAsm(); }
 
-  std::string getTypeName(TypeIndex TI) {
+  std::string getTypeName(TypeIndex TI) override {
     std::string TypeName;
     if (!TI.isNoneType()) {
       if (TI.isSimple())
diff --git a/llvm/lib/Target/AMDGPU/MCTargetDesc/R600MCCodeEmitter.cpp b/llvm/lib/Target/AMDGPU/MCTargetDesc/R600MCCodeEmitter.cpp
--- a/llvm/lib/Target/AMDGPU/MCTargetDesc/R600MCCodeEmitter.cpp
+++ b/llvm/lib/Target/AMDGPU/MCTargetDesc/R600MCCodeEmitter.cpp
@@ -47,7 +47,7 @@
   /// Encode the instruction and write it to the OS.
   void encodeInstruction(const MCInst &MI, raw_ostream &OS,
                          SmallVectorImpl<MCFixup> &Fixups,
-                         const MCSubtargetInfo &STI) const;
+                         const MCSubtargetInfo &STI) const override;
 
   /// \returns the encoding for an MCOperand.
   uint64_t getMachineOpValue(const MCInst &MI, const MCOperand &MO,
diff --git a/llvm/lib/Target/AVR/AVRFrameLowering.cpp b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
--- a/llvm/lib/Target/AVR/AVRFrameLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
@@ -405,7 +405,7 @@
   static char ID;
   AVRFrameAnalyzer() : MachineFunctionPass(ID) {}
 
-  bool runOnMachineFunction(MachineFunction &MF) {
+  bool runOnMachineFunction(MachineFunction &MF) override {
     const MachineFrameInfo &MFI = MF.getFrameInfo();
     AVRMachineFunctionInfo *FuncInfo = MF.getInfo<AVRMachineFunctionInfo>();
 
@@ -457,7 +457,7 @@
     return false;
   }
 
-  StringRef getPassName() const { return "AVR Frame Analyzer"; }
+  StringRef getPassName() const override { return "AVR Frame Analyzer"; }
 };
 
 char AVRFrameAnalyzer::ID = 0;
@@ -473,7 +473,7 @@
   static char ID;
   AVRDynAllocaSR() : MachineFunctionPass(ID) {}
 
-  bool runOnMachineFunction(MachineFunction &MF) {
+  bool runOnMachineFunction(MachineFunction &MF) override {
     // Early exit when there are no variable sized objects in the function.
     if (!MF.getFrameInfo().hasVarSizedObjects()) {
       return false;
@@ -506,7 +506,7 @@
     return true;
   }
 
-  StringRef getPassName() const {
+  StringRef getPassName() const override {
     return "AVR dynalloca stack pointer save/restore";
   }
 };
diff --git a/llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp b/llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
--- a/llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
+++ b/llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp
@@ -178,10 +178,10 @@
     return isUInt<8>(Value);
   }
 
-  bool isReg() const { return Kind == k_Register; }
-  bool isImm() const { return Kind == k_Immediate; }
-  bool isToken() const { return Kind == k_Token; }
-  bool isMem() const { return Kind == k_Memri; }
+  bool isReg() const override { return Kind == k_Register; }
+  bool isImm() const override { return Kind == k_Immediate; }
+  bool isToken() const override { return Kind == k_Token; }
+  bool isMem() const override { return Kind == k_Memri; }
   bool isMemri() const { return Kind == k_Memri; }
 
   StringRef getToken() const {
@@ -189,7 +189,7 @@
     return Tok;
   }
 
-  unsigned getReg() const {
+  unsigned getReg() const override {
     assert((Kind == k_Register || Kind == k_Memri) && "Invalid access!");
 
     return RegImm.Reg;
@@ -239,10 +239,10 @@
     RegImm = {RegNo, Imm};
   }
 
-  SMLoc getStartLoc() const { return Start; }
-  SMLoc getEndLoc() const { return End; }
+  SMLoc getStartLoc() const override { return Start; }
+  SMLoc getEndLoc() const override { return End; }
 
-  virtual void print(raw_ostream &O) const {
+  void print(raw_ostream &O) const override {
     switch (Kind) {
     case k_Token:
       O << "Token: \"" << getToken() << "\"";
diff --git a/llvm/lib/Target/BPF/BTFDebug.h b/llvm/lib/Target/BPF/BTFDebug.h
--- a/llvm/lib/Target/BPF/BTFDebug.h
+++ b/llvm/lib/Target/BPF/BTFDebug.h
@@ -63,8 +63,8 @@
 
 public:
   BTFTypeDerived(const DIDerivedType *Ty, unsigned Tag, bool NeedsFixup);
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
   void setPointeeType(uint32_t PointeeType);
 };
 
@@ -74,8 +74,8 @@
 
 public:
   BTFTypeFwd(StringRef Name, bool IsUnion);
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle int type.
@@ -86,9 +86,9 @@
 public:
   BTFTypeInt(uint32_t Encoding, uint32_t SizeInBits, uint32_t OffsetInBits,
              StringRef TypeName);
-  uint32_t getSize() { return BTFTypeBase::getSize() + sizeof(uint32_t); }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  uint32_t getSize() override { return BTFTypeBase::getSize() + sizeof(uint32_t); }
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle enumerate type.
@@ -98,11 +98,11 @@
 
 public:
   BTFTypeEnum(const DICompositeType *ETy, uint32_t NumValues);
-  uint32_t getSize() {
+  uint32_t getSize() override {
     return BTFTypeBase::getSize() + EnumValues.size() * BTF::BTFEnumSize;
   }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle array type.
@@ -111,9 +111,9 @@
 
 public:
   BTFTypeArray(uint32_t ElemTypeId, uint32_t NumElems);
-  uint32_t getSize() { return BTFTypeBase::getSize() + BTF::BTFArraySize; }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  uint32_t getSize() override { return BTFTypeBase::getSize() + BTF::BTFArraySize; }
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle struct/union type.
@@ -125,11 +125,11 @@
 public:
   BTFTypeStruct(const DICompositeType *STy, bool IsStruct, bool HasBitField,
                 uint32_t NumMembers);
-  uint32_t getSize() {
+  uint32_t getSize() override {
     return BTFTypeBase::getSize() + Members.size() * BTF::BTFMemberSize;
   }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
   std::string getName();
 };
 
@@ -142,11 +142,11 @@
 public:
   BTFTypeFuncProto(const DISubroutineType *STy, uint32_t NumParams,
                    const std::unordered_map<uint32_t, StringRef> &FuncArgNames);
-  uint32_t getSize() {
+  uint32_t getSize() override {
     return BTFTypeBase::getSize() + Parameters.size() * BTF::BTFParamSize;
   }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle subprogram
@@ -155,9 +155,9 @@
 
 public:
   BTFTypeFunc(StringRef FuncName, uint32_t ProtoTypeId, uint32_t Scope);
-  uint32_t getSize() { return BTFTypeBase::getSize(); }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  uint32_t getSize() override { return BTFTypeBase::getSize(); }
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle variable instances
@@ -167,9 +167,9 @@
 
 public:
   BTFKindVar(StringRef VarName, uint32_t TypeId, uint32_t VarInfo);
-  uint32_t getSize() { return BTFTypeBase::getSize() + 4; }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  uint32_t getSize() override { return BTFTypeBase::getSize() + 4; }
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// Handle data sections
@@ -180,15 +180,15 @@
 
 public:
   BTFKindDataSec(AsmPrinter *AsmPrt, std::string SecName);
-  uint32_t getSize() {
+  uint32_t getSize() override {
     return BTFTypeBase::getSize() + BTF::BTFDataSecVarSize * Vars.size();
   }
   void addVar(uint32_t Id, const MCSymbol *Sym, uint32_t Size) {
     Vars.push_back(std::make_tuple(Id, Sym, Size));
   }
   std::string getName() { return Name; }
-  void completeType(BTFDebug &BDebug);
-  void emitType(MCStreamer &OS);
+  void completeType(BTFDebug &BDebug) override;
+  void emitType(MCStreamer &OS) override;
 };
 
 /// String table.
diff --git a/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp b/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
--- a/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
+++ b/llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp
@@ -156,12 +156,12 @@
     addExprOperand(Inst, Mem.Offset);
   }
 
-  bool isReg() const        { return Kind == k_Reg; }
-  bool isImm() const        { return Kind == k_Imm; }
-  bool isToken() const      { return Kind == k_Tok; }
-  bool isMem() const        { return Kind == k_Mem; }
-  bool isIndReg() const     { return Kind == k_IndReg; }
-  bool isPostIndReg() const { return Kind == k_PostIndReg; }
+  bool isReg()   const override { return Kind == k_Reg; }
+  bool isImm()   const override { return Kind == k_Imm; }
+  bool isToken() const override { return Kind == k_Tok; }
+  bool isMem()   const override { return Kind == k_Mem; }
+  bool isIndReg()         const { return Kind == k_IndReg; }
+  bool isPostIndReg()     const { return Kind == k_PostIndReg; }
 
   bool isCGImm() const {
     if (Kind != k_Imm)
@@ -182,7 +182,7 @@
     return Tok;
   }
 
-  unsigned getReg() const {
+  unsigned getReg() const override {
     assert(Kind == k_Reg && "Invalid access!");
     return Reg;
   }
@@ -222,10 +222,10 @@
     return std::make_unique<MSP430Operand>(k_PostIndReg, RegNum, S, E);
   }
 
-  SMLoc getStartLoc() const { return Start; }
-  SMLoc getEndLoc() const { return End; }
+  SMLoc getStartLoc() const override { return Start; }
+  SMLoc getEndLoc() const override { return End; }
 
-  virtual void print(raw_ostream &O) const {
+  void print(raw_ostream &O) const override {
     switch (Kind) {
     case k_Tok:
       O << "Token " << Tok;
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.h b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.h
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.h
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.h
@@ -28,7 +28,7 @@
 };
 
 class PPCXCOFFMCAsmInfo : public MCAsmInfoXCOFF {
-  virtual void anchor();
+  void anchor() override;
 
 public:
   explicit PPCXCOFFMCAsmInfo(bool is64Bit, const Triple &);
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.h b/llvm/lib/Target/X86/X86TargetTransformInfo.h
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.h
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.h
@@ -105,9 +105,9 @@
   /// \name Cache TTI Implementation
   /// @{
   llvm::Optional<unsigned> getCacheSize(
-    TargetTransformInfo::CacheLevel Level) const;
+    TargetTransformInfo::CacheLevel Level) const override;
   llvm::Optional<unsigned> getCacheAssociativity(
-    TargetTransformInfo::CacheLevel Level) const;
+    TargetTransformInfo::CacheLevel Level) const override;
   /// @}
 
   /// \name Vector TTI Implementations
diff --git a/llvm/lib/Transforms/Utils/FixIrreducible.cpp b/llvm/lib/Transforms/Utils/FixIrreducible.cpp
--- a/llvm/lib/Transforms/Utils/FixIrreducible.cpp
+++ b/llvm/lib/Transforms/Utils/FixIrreducible.cpp
@@ -84,7 +84,7 @@
     initializeFixIrreduciblePass(*PassRegistry::getPassRegistry());
   }
 
-  void getAnalysisUsage(AnalysisUsage &AU) const {
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequiredID(LowerSwitchID);
     AU.addRequired<DominatorTreeWrapperPass>();
     AU.addRequired<LoopInfoWrapperPass>();
@@ -93,7 +93,7 @@
     AU.addPreserved<LoopInfoWrapperPass>();
   }
 
-  bool runOnFunction(Function &F);
+  bool runOnFunction(Function &F) override;
 };
 } // namespace
 
diff --git a/llvm/lib/Transforms/Utils/PredicateInfo.cpp b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
--- a/llvm/lib/Transforms/Utils/PredicateInfo.cpp
+++ b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
@@ -885,11 +885,11 @@
 public:
   PredicateInfoAnnotatedWriter(const PredicateInfo *M) : PredInfo(M) {}
 
-  virtual void emitBasicBlockStartAnnot(const BasicBlock *BB,
-                                        formatted_raw_ostream &OS) {}
+  void emitBasicBlockStartAnnot(const BasicBlock *BB,
+                                formatted_raw_ostream &OS) override {}
 
-  virtual void emitInstructionAnnot(const Instruction *I,
-                                    formatted_raw_ostream &OS) {
+  void emitInstructionAnnot(const Instruction *I,
+                            formatted_raw_ostream &OS) override {
     if (const auto *PI = PredInfo->getPredicateInfoFor(I)) {
       OS << "; Has predicate info\n";
       if (const auto *PB = dyn_cast<PredicateBranch>(PI)) {
diff --git a/llvm/lib/Transforms/Utils/UnifyLoopExits.cpp b/llvm/lib/Transforms/Utils/UnifyLoopExits.cpp
--- a/llvm/lib/Transforms/Utils/UnifyLoopExits.cpp
+++ b/llvm/lib/Transforms/Utils/UnifyLoopExits.cpp
@@ -33,7 +33,7 @@
     initializeUnifyLoopExitsPass(*PassRegistry::getPassRegistry());
   }
 
-  void getAnalysisUsage(AnalysisUsage &AU) const {
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequiredID(LowerSwitchID);
     AU.addRequired<LoopInfoWrapperPass>();
     AU.addRequired<DominatorTreeWrapperPass>();
@@ -42,7 +42,7 @@
     AU.addPreserved<DominatorTreeWrapperPass>();
   }
 
-  bool runOnFunction(Function &F);
+  bool runOnFunction(Function &F) override;
 };
 } // namespace