[MC] Add "override" where appropriate (NFC) (llvm#165135)

Note that "override" makes "virtual" redundant.

Identified with modernize-use-override.

Author: kazutakahirata

llvm/include/llvm/MC/MCDXContainerWriter.h

@@ -23,7 +23,7 @@ class MCDXContainerTargetWriter : public MCObjectTargetWriter {
   MCDXContainerTargetWriter() {}
 
 public:
-  virtual ~MCDXContainerTargetWriter();
+  ~MCDXContainerTargetWriter() override;
 
   Triple::ObjectFormatType getFormat() const override {
     return Triple::DXContainer;

llvm/include/llvm/MC/MCELFObjectWriter.h

@@ -62,7 +62,7 @@ class MCELFObjectTargetWriter : public MCObjectTargetWriter {
                           bool HasRelocationAddend_, uint8_t ABIVersion_ = 0);
 
 public:
-  virtual ~MCELFObjectTargetWriter() = default;
+  ~MCELFObjectTargetWriter() override = default;
 
   Triple::ObjectFormatType getFormat() const override { return Triple::ELF; }
   static bool classof(const MCObjectTargetWriter *W) {

llvm/include/llvm/MC/MCGOFFObjectWriter.h

@@ -21,7 +21,7 @@ class MCGOFFObjectTargetWriter : public MCObjectTargetWriter {
   MCGOFFObjectTargetWriter() = default;
 
 public:
-  virtual ~MCGOFFObjectTargetWriter() = default;
+  ~MCGOFFObjectTargetWriter() override = default;
 
   Triple::ObjectFormatType getFormat() const override { return Triple::GOFF; }
 

llvm/include/llvm/MC/MCMachObjectWriter.h

@@ -48,7 +48,7 @@ class LLVM_ABI MCMachObjectTargetWriter : public MCObjectTargetWriter {
   }
 
 public:
-  virtual ~MCMachObjectTargetWriter();
+  ~MCMachObjectTargetWriter() override;
 
   Triple::ObjectFormatType getFormat() const override { return Triple::MachO; }
   static bool classof(const MCObjectTargetWriter *W) {

llvm/include/llvm/MC/MCObjectStreamer.h

@@ -68,7 +68,7 @@ class MCObjectStreamer : public MCStreamer {
   MCObjectStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
                    std::unique_ptr<MCObjectWriter> OW,
                    std::unique_ptr<MCCodeEmitter> Emitter);
-  ~MCObjectStreamer();
+  ~MCObjectStreamer() override;
 
 public:
   /// state management

llvm/include/llvm/MC/MCWasmObjectWriter.h

@@ -27,7 +27,7 @@ class MCWasmObjectTargetWriter : public MCObjectTargetWriter {
   explicit MCWasmObjectTargetWriter(bool Is64Bit_, bool IsEmscripten);
 
 public:
-  virtual ~MCWasmObjectTargetWriter();
+  ~MCWasmObjectTargetWriter() override;
 
   Triple::ObjectFormatType getFormat() const override { return Triple::Wasm; }
   static bool classof(const MCObjectTargetWriter *W) {

llvm/include/llvm/MC/MCWinCOFFObjectWriter.h

@@ -29,7 +29,7 @@ class MCWinCOFFObjectTargetWriter : public MCObjectTargetWriter {
   MCWinCOFFObjectTargetWriter(unsigned Machine_);
 
 public:
-  virtual ~MCWinCOFFObjectTargetWriter() = default;
+  ~MCWinCOFFObjectTargetWriter() override = default;
 
   Triple::ObjectFormatType getFormat() const override { return Triple::COFF; }
   static bool classof(const MCObjectTargetWriter *W) {

llvm/lib/MC/GOFFObjectWriter.cpp

@@ -440,7 +440,7 @@ class TextStream : public raw_ostream {
     SetBuffer(Buffer, sizeof(Buffer));
   }
 
-  ~TextStream() { flush(); }
+  ~TextStream() override { flush(); }
 };
 } // namespace
 

llvm/lib/MC/MCAsmStreamer.cpp

@@ -295,7 +295,7 @@ class MCAsmStreamer final : public MCStreamer {
                              unsigned Flags, unsigned Isa,
                              unsigned Discriminator, StringRef FileName,
                              StringRef Location = {}) override;
-  virtual void emitDwarfLocLabelDirective(SMLoc Loc, StringRef Name) override;
+  void emitDwarfLocLabelDirective(SMLoc Loc, StringRef Name) override;
 
   MCSymbol *getDwarfLineTableSymbol(unsigned CUID) override;
 

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -726,7 +726,7 @@ class HLASMAsmParser final : public AsmParser {
     Lexer.setLexHLASMStrings(true);
   }
 
-  ~HLASMAsmParser() { Lexer.setSkipSpace(true); }
+  ~HLASMAsmParser() override { Lexer.setSkipSpace(true); }
 
   bool parseStatement(ParseStatementInfo &Info,
                       MCAsmParserSemaCallback *SI) override;