MCSymbolELF: Migrate away from classof

The object file format specific derived classes are used in context
where the type is statically known. We don't use isa/dyn_cast and we
want to eliminate MCSymbol::Kind in the base class.

Author: MaskRay

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -3194,7 +3194,7 @@ void AsmPrinter::emitJumpTableSizesSection(const MachineJumpTableInfo &MJTI,
     return;
 
   if (isElf) {
-    MCSymbolELF *LinkedToSym = dyn_cast<MCSymbolELF>(CurrentFnSym);
+    auto *LinkedToSym = static_cast<MCSymbolELF *>(CurrentFnSym);
     int Flags = F.hasComdat() ? static_cast<int>(ELF::SHF_GROUP) : 0;
 
     JumpTableSizesSection = OutContext.getELFSection(

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

@@ -581,7 +581,8 @@ static const MCSymbolELF *getLinkedToSymbol(const GlobalObject *GO,
 
   auto *VM = cast<ValueAsMetadata>(MD->getOperand(0).get());
   auto *OtherGV = dyn_cast<GlobalValue>(VM->getValue());
-  return OtherGV ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGV)) : nullptr;
+  return OtherGV ? static_cast<const MCSymbolELF *>(TM.getSymbol(OtherGV))
+                 : nullptr;
 }
 
 static unsigned getEntrySizeForKind(SectionKind Kind) {
@@ -1011,7 +1012,7 @@ MCSection *TargetLoweringObjectFileELF::getSectionForLSDA(
       (getContext().getAsmInfo()->useIntegratedAssembler() &&
        getContext().getAsmInfo()->binutilsIsAtLeast(2, 36))) {
     Flags |= ELF::SHF_LINK_ORDER;
-    LinkedToSym = cast<MCSymbolELF>(&FnSym);
+    LinkedToSym = static_cast<const MCSymbolELF *>(&FnSym);
   }
 
   // Append the function name as the suffix like GCC, assuming

llvm/lib/MC/ELFObjectWriter.cpp

@@ -409,8 +409,7 @@ static bool isIFunc(const MCSymbolELF *Symbol) {
 void ELFWriter::writeSymbol(SymbolTableWriter &Writer, uint32_t StringIndex,
                             ELFSymbolData &MSD) {
   auto &Symbol = static_cast<const MCSymbolELF &>(*MSD.Symbol);
-  const MCSymbolELF *Base =
-      cast_or_null<MCSymbolELF>(Asm.getBaseSymbol(Symbol));
+  auto *Base = static_cast<const MCSymbolELF *>(Asm.getBaseSymbol(Symbol));
 
   // This has to be in sync with when computeSymbolTable uses SHN_ABS or
   // SHN_COMMON.
@@ -1317,7 +1316,7 @@ void ELFObjectWriter::recordRelocation(const MCFragment &F,
   auto &Section = static_cast<const MCSectionELF &>(*F.getParent());
   MCContext &Ctx = getContext();
 
-  const auto *SymA = cast_or_null<MCSymbolELF>(Target.getAddSym());
+  auto *SymA = static_cast<const MCSymbolELF *>(Target.getAddSym());
   const MCSectionELF *SecA =
       (SymA && SymA->isInSection())
           ? static_cast<const MCSectionELF *>(&SymA->getSection())

llvm/lib/MC/MCContext.cpp

@@ -446,7 +446,7 @@ Symbol *MCContext::getOrCreateSectionSymbol(StringRef Section) {
   // Use the symbol's index to track if it has been used as a section symbol.
   // Set to -1 to catch potential bugs if misused as a symbol index.
   if (Sym && Sym->getIndex() != -1u) {
-    R = cast<Symbol>(Sym);
+    R = static_cast<Symbol *>(Sym);
   } else {
     SymEntry.second.Used = true;
     R = new (&SymEntry, *this) Symbol(&SymEntry, /*isTemporary=*/false);
@@ -586,7 +586,7 @@ MCContext::createELFRelSection(const Twine &Name, unsigned Type, unsigned Flags,
 
   return createELFSectionImpl(
       I->getKey(), Type, Flags, EntrySize, Group, true, true,
-      cast<MCSymbolELF>(RelInfoSection->getBeginSymbol()));
+      static_cast<const MCSymbolELF *>(RelInfoSection->getBeginSymbol()));
 }
 
 MCSectionELF *MCContext::getELFNamedSection(const Twine &Prefix,

llvm/lib/MC/MCELFStreamer.cpp

@@ -272,8 +272,8 @@ void MCELFStreamer::emitCommonSymbol(MCSymbol *S, uint64_t Size,
                          " redeclared as different type");
   }
 
-  cast<MCSymbolELF>(Symbol)
-      ->setSize(MCConstantExpr::create(Size, getContext()));
+  static_cast<MCSymbolELF *>(Symbol)->setSize(
+      MCConstantExpr::create(Size, getContext()));
 }
 
 void MCELFStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {

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

@@ -96,7 +96,7 @@ void HexagonMCELFStreamer::HexagonMCEmitCommonSymbol(MCSymbol *Symbol,
   getAssembler().registerSymbol(*Symbol);
   StringRef sbss[4] = {".sbss.1", ".sbss.2", ".sbss.4", ".sbss.8"};
 
-  auto ELFSymbol = cast<MCSymbolELF>(Symbol);
+  auto ELFSymbol = static_cast<MCSymbolELF *>(Symbol);
   if (!ELFSymbol->isBindingSet())
     ELFSymbol->setBinding(ELF::STB_GLOBAL);
 
@@ -143,7 +143,7 @@ void HexagonMCELFStreamer::HexagonMCEmitLocalCommonSymbol(MCSymbol *Symbol,
                                                           Align ByteAlignment,
                                                           unsigned AccessSize) {
   getAssembler().registerSymbol(*Symbol);
-  auto ELFSymbol = cast<MCSymbolELF>(Symbol);
+  auto ELFSymbol = static_cast<const MCSymbolELF *>(Symbol);
   ELFSymbol->setBinding(ELF::STB_LOCAL);
   ELFSymbol->setExternal(false);
   HexagonMCEmitCommonSymbol(Symbol, Size, ByteAlignment, AccessSize);