MCSymbol: Move isExported/setExported to MCSymbol{COFF,MachO,Wasm}

Make it clear that other object file formats (e.g. ELF) do not use this
field.

Author: MaskRay

llvm/include/llvm/MC/MCSymbol.h

@@ -352,10 +352,6 @@ class MCSymbol {
     return Fragment;
   }
 
-  // For ELF, use MCSymbolELF::setBinding instead.
-  bool isExternal() const { return IsExternal; }
-  void setExternal(bool Value) const { IsExternal = Value; }
-
   // COFF-specific
   bool isWeakExternal() const { return IsWeakExternal; }
 

llvm/include/llvm/MC/MCSymbolCOFF.h

@@ -33,6 +33,9 @@ class MCSymbolCOFF : public MCSymbol {
   MCSymbolCOFF(const MCSymbolTableEntry *Name, bool isTemporary)
       : MCSymbol(Name, isTemporary) {}
 
+  bool isExternal() const { return IsExternal; }
+  void setExternal(bool Value) const { IsExternal = Value; }
+
   uint16_t getType() const {
     return Type;
   }

llvm/include/llvm/MC/MCSymbolMachO.h

@@ -46,6 +46,8 @@ class MCSymbolMachO : public MCSymbol {
   MCSymbolMachO(const MCSymbolTableEntry *Name, bool isTemporary)
       : MCSymbol(Name, isTemporary) {}
 
+  bool isExternal() const { return IsExternal; }
+  void setExternal(bool Value) const { IsExternal = Value; }
   bool isPrivateExtern() const { return IsPrivateExtern; }
   void setPrivateExtern(bool Value) { IsPrivateExtern = Value; }
 

llvm/include/llvm/MC/MCSymbolWasm.h

@@ -37,6 +37,8 @@ class MCSymbolWasm : public MCSymbol {
   MCSymbolWasm(const MCSymbolTableEntry *Name, bool isTemporary)
       : MCSymbol(Name, isTemporary) {}
 
+  bool isExternal() const { return IsExternal; }
+  void setExternal(bool Value) const { IsExternal = Value; }
   const MCExpr *getSize() const { return SymbolSize; }
   void setSize(const MCExpr *SS) { SymbolSize = SS; }
 

llvm/include/llvm/MC/MCSymbolXCOFF.h

@@ -37,6 +37,8 @@ class MCSymbolXCOFF : public MCSymbol {
     return Name;
   }
 
+  bool isExternal() const { return IsExternal; }
+  void setExternal(bool Value) const { IsExternal = Value; }
   void setStorageClass(XCOFF::StorageClass SC) {
     StorageClass = SC;
   };

llvm/lib/MC/MCContext.cpp

@@ -326,7 +326,6 @@ MCSymbol *MCContext::cloneSymbol(MCSymbol &Sym) {
 
   // Ensure the original symbol is not emitted to the symbol table.
   Sym.IsTemporary = true;
-  Sym.setExternal(false);
   return NewSym;
 }
 

llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp

@@ -144,7 +144,6 @@ void HexagonMCELFStreamer::HexagonMCEmitLocalCommonSymbol(MCSymbol *Symbol,
   getAssembler().registerSymbol(*Symbol);
   auto ELFSymbol = static_cast<const MCSymbolELF *>(Symbol);
   ELFSymbol->setBinding(ELF::STB_LOCAL);
-  ELFSymbol->setExternal(false);
   HexagonMCEmitCommonSymbol(Symbol, Size, ByteAlignment, AccessSize);
 }