[MC] Clean up unused inline function and non-anchor defaulted destructors; NFCI

[hubert.reinterpretcast]

Summary

Take care of some missing clean-ups that belong with r249548 and some other copy/paste that had happened. In particular, the destructors are no longer vtable anchors after r249548; and setSectionName in MCSectionWasm is private and unused since r313058 culled its only caller. The destructors are now implicitly defined, and the unused function is removed.

[nemanjai]

This looks to me like the right thing to do but I added Jim Grosbach as a reviewer since he owns the MC layer.

[sbc100]

lib/MC/MCSectionCOFF.cpp

17

If its not longer an anchor then presumably it can be removed from the .cpp file? And in fact since its empty removed from the .h file too?

Ditto for ELF and wasm files.

[hubert.reinterpretcast]

lib/MC/MCSectionCOFF.cpp

17

Yes, I think I will do that. It does not look like these destructors do much other than calling the base destructor, and the base destructor is already out-of-line.

[hubert.reinterpretcast]

Address comments: Let public defaulted destructors be implicitly defined

[hubert.reinterpretcast]

A friendly ping?

[nemanjai]

LGTM. Maybe give it a couple of days in case someone else has an objection.

[sbc100]

lgtm.

I assume its safe to remove the destructors here as they were only used for anchors and these class have other virtual functions in the cpp files already. The rules for anchor methods are here: https://llvm.org/docs/CodingStandards.html#provide-a-virtual-method-anchor-for-classes-in-headers.

include/llvm/MC/MCSectionCOFF.h

MCSectionCOFF(StringRef Section, unsigned Characteristics,
       : MCSection(SV_COFF, K, Begin), SectionName(Section),
         Characteristics(Characteristics), COMDATSymbol(COMDATSymbol),
         Selection(Selection) {
     assert((Characteristics & 0x00F00000) == 0 &&
            "alignment must not be set upon section creation");
   }
 
 public:
-  ~MCSectionCOFF();
-
   /// Decides whether a '.section' directive should be printed before the
   /// section name
   bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
 
   StringRef getSectionName() const { return SectionName; }
   unsigned getCharacteristics() const { return Characteristics; }
   MCSymbol *getCOMDATSymbol() const { return COMDATSymbol; }
   int getSelection() const { return Selection; }

include/llvm/MC/MCSectionELF.h

MCSectionELF(StringRef Section, unsigned type, unsigned flags, SectionKind K,
         AssociatedSymbol(AssociatedSymbol) {
     if (Group)
       Group->setIsSignature();
   }
 
   void setSectionName(StringRef Name) { SectionName = Name; }
 
 public:
-  ~MCSectionELF();
-
   /// Decides whether a '.section' directive should be printed before the
   /// section name
   bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
 
   StringRef getSectionName() const { return SectionName; }
   unsigned getType() const { return Type; }
   unsigned getFlags() const { return Flags; }
   unsigned getEntrySize() const { return EntrySize; }

include/llvm/MC/MCSectionWasm.h

class MCSectionWasm final : public MCSection {
   uint32_t SegmentIndex = 0;
 
   friend class MCContext;
   MCSectionWasm(StringRef Section, SectionKind K, const MCSymbolWasm *group,
                 unsigned UniqueID, MCSymbol *Begin)
       : MCSection(SV_Wasm, K, Begin), SectionName(Section), UniqueID(UniqueID),
         Group(group) {}
 
-  void setSectionName(StringRef Name) { SectionName = Name; }
-
 public:
-  ~MCSectionWasm();
-
   /// Decides whether a '.section' directive should be printed before the
   /// section name
   bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
 
   StringRef getSectionName() const { return SectionName; }
   const MCSymbolWasm *getGroup() const { return Group; }
 
   void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,

lib/MC/MCSectionCOFF.cpp

 //===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCSectionCOFF.h"
 #include "llvm/BinaryFormat/COFF.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 
 using namespace llvm;
 
-MCSectionCOFF::~MCSectionCOFF() = default; // anchor.
-
 // ShouldOmitSectionDirective - Decides whether a '.section' directive
 // should be printed before the section name
 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
                                                const MCAsmInfo &MAI) const {
   if (COMDATSymbol)
     return false;
 
   // FIXME: Does .section .bss/.data/.text work everywhere??

lib/MC/MCSectionELF.cpp

 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 
 using namespace llvm;
 
-MCSectionELF::~MCSectionELF() = default; // anchor.
-
 // Decides whether a '.section' directive
 // should be printed before the section name.
 bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name,
                                               const MCAsmInfo &MAI) const {
   if (isUnique())
     return false;
 
   return MAI.shouldOmitSectionDirective(Name);

lib/MC/MCSectionWasm.cpp

 //===- lib/MC/MCSectionWasm.cpp - Wasm Code Section Representation --------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCSectionWasm.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
-MCSectionWasm::~MCSectionWasm() {} // anchor.
-
 // Decides whether a '.section' directive
 // should be printed before the section name.
 bool MCSectionWasm::ShouldOmitSectionDirective(StringRef Name,
                                                const MCAsmInfo &MAI) const {
   return MAI.shouldOmitSectionDirective(Name);
 }
 
 static void printName(raw_ostream &OS, StringRef Name) {