MCSectionXCOFF: Remove classof

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

Author: MaskRay

llvm/include/llvm/MC/MCSectionXCOFF.h

@@ -95,10 +95,6 @@ class MCSectionXCOFF final : public MCSection {
 public:
   ~MCSectionXCOFF();
 
-  static bool classof(const MCSection *S) {
-    return S->getVariant() == SV_XCOFF;
-  }
-
   XCOFF::StorageMappingClass getMappingClass() const {
     assert(isCsect() && "Only csect section has mapping class property!");
     return CsectProp->MappingClass;

llvm/lib/CodeGen/AsmPrinter/AIXException.cpp

@@ -37,8 +37,8 @@ void AIXException::emitExceptionInfoTable(const MCSymbol *LSDA,
   //   unsigned long personality;  /* Pointer to the personality routine */
   //   }
 
-  auto *EHInfo =
-      cast<MCSectionXCOFF>(Asm->getObjFileLowering().getCompactUnwindSection());
+  auto *EHInfo = static_cast<MCSectionXCOFF *>(
+      Asm->getObjFileLowering().getCompactUnwindSection());
   if (Asm->TM.getFunctionSections()) {
     // If option -ffunction-sections is on, append the function name to the
     // name of EH Info Table csect so that each function has its own EH Info

llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

@@ -2388,23 +2388,25 @@ TargetLoweringObjectFileXCOFF::getTargetSymbol(const GlobalValue *GV,
   // here.
   if (const GlobalObject *GO = dyn_cast<GlobalObject>(GV)) {
     if (GO->isDeclarationForLinker())
-      return cast<MCSectionXCOFF>(getSectionForExternalReference(GO, TM))
+      return static_cast<const MCSectionXCOFF *>(
+                 getSectionForExternalReference(GO, TM))
           ->getQualNameSymbol();
 
     if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
       if (GVar->hasAttribute("toc-data"))
-        return cast<MCSectionXCOFF>(
+        return static_cast<const MCSectionXCOFF *>(
                    SectionForGlobal(GVar, SectionKind::getData(), TM))
             ->getQualNameSymbol();
 
     SectionKind GOKind = getKindForGlobal(GO, TM);
     if (GOKind.isText())
-      return cast<MCSectionXCOFF>(
+      return static_cast<const MCSectionXCOFF *>(
                  getSectionForFunctionDescriptor(cast<Function>(GO), TM))
           ->getQualNameSymbol();
     if ((TM.getDataSections() && !GO->hasSection()) || GO->hasCommonLinkage() ||
         GOKind.isBSSLocal() || GOKind.isThreadBSSLocal())
-      return cast<MCSectionXCOFF>(SectionForGlobal(GO, GOKind, TM))
+      return static_cast<const MCSectionXCOFF *>(
+                 SectionForGlobal(GO, GOKind, TM))
           ->getQualNameSymbol();
   }
 
@@ -2740,7 +2742,7 @@ MCSection *TargetLoweringObjectFileXCOFF::getSectionForTOCEntry(
 
 MCSection *TargetLoweringObjectFileXCOFF::getSectionForLSDA(
     const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const {
-  auto *LSDA = cast<MCSectionXCOFF>(LSDASection);
+  auto *LSDA = static_cast<MCSectionXCOFF *>(LSDASection);
   if (TM.getFunctionSections()) {
     // If option -ffunction-sections is on, append the function name to the
     // name of the LSDA csect so that each function has its own LSDA csect.

llvm/lib/MC/MCXCOFFStreamer.cpp

@@ -38,7 +38,7 @@ XCOFFObjectWriter &MCXCOFFStreamer::getWriter() {
 
 void MCXCOFFStreamer::changeSection(MCSection *Section, uint32_t Subsection) {
   MCObjectStreamer::changeSection(Section, Subsection);
-  auto *Sec = cast<MCSectionXCOFF>(Section);
+  auto *Sec = static_cast<const MCSectionXCOFF *>(Section);
   // We might miss calculating the symbols difference as absolute value before
   // adding fixups when symbol_A without the fragment set is the csect itself
   // and symbol_B is in it.

llvm/lib/MC/XCOFFObjectWriter.cpp

@@ -550,13 +550,13 @@ CsectGroup &XCOFFWriter::getCsectGroup(const MCSectionXCOFF *MCSec) {
 
 static MCSectionXCOFF *getContainingCsect(const MCSymbolXCOFF *XSym) {
   if (XSym->isDefined())
-    return cast<MCSectionXCOFF>(XSym->getFragment()->getParent());
+    return static_cast<MCSectionXCOFF *>(XSym->getFragment()->getParent());
   return XSym->getRepresentedCsect();
 }
 
 void XCOFFWriter::executePostLayoutBinding() {
   for (const auto &S : *Asm) {
-    const auto *MCSec = cast<const MCSectionXCOFF>(&S);
+    auto *MCSec = static_cast<const MCSectionXCOFF *>(&S);
     assert(!SectionMap.contains(MCSec) && "Cannot add a section twice.");
 
     // If the name does not fit in the storage provided in the symbol table
@@ -747,7 +747,7 @@ void XCOFFWriter::recordRelocation(const MCFragment &F, const MCFixup &Fixup,
       FixedValue = TOCEntryOffset;
     }
   } else if (Type == XCOFF::RelocationType::R_RBR) {
-    MCSectionXCOFF *ParentSec = cast<MCSectionXCOFF>(F.getParent());
+    auto *ParentSec = static_cast<MCSectionXCOFF *>(F.getParent());
     assert((SymASec->getMappingClass() == XCOFF::XMC_PR &&
             ParentSec->getMappingClass() == XCOFF::XMC_PR) &&
            "Only XMC_PR csect may have the R_RBR relocation.");
@@ -768,7 +768,7 @@ void XCOFFWriter::recordRelocation(const MCFragment &F, const MCFixup &Fixup,
   }
 
   XCOFFRelocation Reloc = {Index, FixupOffsetInCsect, SignAndSize, Type};
-  MCSectionXCOFF *RelocationSec = cast<MCSectionXCOFF>(F.getParent());
+  auto *RelocationSec = static_cast<MCSectionXCOFF *>(F.getParent());
   assert(SectionMap.contains(RelocationSec) &&
          "Expected containing csect to exist in map.");
   SectionMap[RelocationSec]->Relocations.push_back(Reloc);

llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp

@@ -213,7 +213,7 @@ class PPCTargetAsmStreamer : public PPCTargetStreamer {
   void emitTCEntry(const MCSymbol &S, PPCMCExpr::Specifier Kind) override {
     if (const MCSymbolXCOFF *XSym = dyn_cast<MCSymbolXCOFF>(&S)) {
       MCSymbolXCOFF *TCSym =
-          cast<MCSectionXCOFF>(Streamer.getCurrentSectionOnly())
+          static_cast<const MCSectionXCOFF *>(Streamer.getCurrentSectionOnly())
               ->getQualNameSymbol();
       // On AIX, we have TLS variable offsets (symbol@({gd|ie|le|ld}) depending
       // on the TLS access method (or model). For the general-dynamic access

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

@@ -2274,9 +2274,9 @@ void PPCAIXAsmPrinter::emitLinkage(const GlobalValue *GV,
 
 void PPCAIXAsmPrinter::SetupMachineFunction(MachineFunction &MF) {
   // Setup CurrentFnDescSym and its containing csect.
-  MCSectionXCOFF *FnDescSec =
-      cast<MCSectionXCOFF>(getObjFileLowering().getSectionForFunctionDescriptor(
-          &MF.getFunction(), TM));
+  auto *FnDescSec = static_cast<MCSectionXCOFF *>(
+      getObjFileLowering().getSectionForFunctionDescriptor(&MF.getFunction(),
+                                                           TM));
   FnDescSec->setAlignment(Align(Subtarget->isPPC64() ? 8 : 4));
 
   CurrentFnDescSym = FnDescSec->getQualNameSymbol();
@@ -2669,9 +2669,9 @@ void PPCAIXAsmPrinter::emitTracebackTable() {
     MCSymbol *EHInfoSym =
         TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(MF);
     MCSymbol *TOCEntry = lookUpOrCreateTOCEntry(EHInfoSym, TOCType_EHBlock);
-    const MCSymbol *TOCBaseSym =
-        cast<MCSectionXCOFF>(getObjFileLowering().getTOCBaseSection())
-            ->getQualNameSymbol();
+    const MCSymbol *TOCBaseSym = static_cast<const MCSectionXCOFF *>(
+                                     getObjFileLowering().getTOCBaseSection())
+                                     ->getQualNameSymbol();
     const MCExpr *Exp =
         MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCEntry, Ctx),
                                 MCSymbolRefExpr::create(TOCBaseSym, Ctx), Ctx);
@@ -2788,7 +2788,7 @@ void PPCAIXAsmPrinter::emitGlobalVariableHelper(const GlobalVariable *GV) {
     }
   }
 
-  MCSectionXCOFF *Csect = cast<MCSectionXCOFF>(
+  auto *Csect = static_cast<MCSectionXCOFF *>(
       getObjFileLowering().SectionForGlobal(GV, GVKind, TM));
 
   // Switch to the containing csect.
@@ -2869,9 +2869,9 @@ void PPCAIXAsmPrinter::emitFunctionDescriptor() {
   OutStreamer->emitValue(MCSymbolRefExpr::create(CurrentFnSym, OutContext),
                          PointerSize);
   // Emit TOC base address.
-  const MCSymbol *TOCBaseSym =
-      cast<MCSectionXCOFF>(getObjFileLowering().getTOCBaseSection())
-          ->getQualNameSymbol();
+  const MCSymbol *TOCBaseSym = static_cast<const MCSectionXCOFF *>(
+                                   getObjFileLowering().getTOCBaseSection())
+                                   ->getQualNameSymbol();
   OutStreamer->emitValue(MCSymbolRefExpr::create(TOCBaseSym, OutContext),
                          PointerSize);
   // Emit a null environment pointer.
@@ -2996,10 +2996,10 @@ void PPCAIXAsmPrinter::emitEndOfAsmFile(Module &M) {
       Name += Prefix;
       Name += cast<MCSymbolXCOFF>(I.first.first)->getSymbolTableName();
       MCSymbol *S = OutContext.getOrCreateSymbol(Name);
-      TCEntry = cast<MCSectionXCOFF>(
+      TCEntry = static_cast<MCSectionXCOFF *>(
           getObjFileLowering().getSectionForTOCEntry(S, TM));
     } else {
-      TCEntry = cast<MCSectionXCOFF>(
+      TCEntry = static_cast<MCSectionXCOFF *>(
           getObjFileLowering().getSectionForTOCEntry(I.first.first, TM));
     }
     OutStreamer->switchSection(TCEntry);
@@ -3054,7 +3054,7 @@ bool PPCAIXAsmPrinter::doInitialization(Module &M) {
       return;
 
     SectionKind GOKind = getObjFileLowering().getKindForGlobal(GO, TM);
-    MCSectionXCOFF *Csect = cast<MCSectionXCOFF>(
+    auto *Csect = static_cast<MCSectionXCOFF *>(
         getObjFileLowering().SectionForGlobal(GO, GOKind, TM));
 
     Align GOAlign = getGVAlignment(GO, GO->getDataLayout());
@@ -3316,9 +3316,9 @@ void PPCAIXAsmPrinter::emitTTypeReference(const GlobalValue *GV,
       GlobalType = TOCType_GlobalExternal;
     MCSymbol *TypeInfoSym = TM.getSymbol(GV);
     MCSymbol *TOCEntry = lookUpOrCreateTOCEntry(TypeInfoSym, GlobalType);
-    const MCSymbol *TOCBaseSym =
-        cast<MCSectionXCOFF>(getObjFileLowering().getTOCBaseSection())
-            ->getQualNameSymbol();
+    const MCSymbol *TOCBaseSym = static_cast<const MCSectionXCOFF *>(
+                                     getObjFileLowering().getTOCBaseSection())
+                                     ->getQualNameSymbol();
     auto &Ctx = OutStreamer->getContext();
     const MCExpr *Exp =
         MCBinaryExpr::createSub(MCSymbolRefExpr::create(TOCEntry, Ctx),