Fix the type of the Discared section

[• rafael]

Summary

It is constructed with a kind of Regular and will dyn_cast to InputSection, but is declared to be an InputSectionBase.

[ruiu]

ELF/InputSection.cpp

326

I wonder if you can avoid adding a new constructor by

InputSection InputSection::Discard(0, 0, 0, ArrayRef<uint8_t>(), "");

[• rafael]

Use existing constructor.

[ruiu]

LGTM

[• espindola]

r320539

ELF/InputSection.h

SectionBase(Kind SectionKind, StringRef Name, uint64_t Flags,
       : Name(Name), SectionKind(SectionKind), Live(false), Bss(false),
         Alignment(Alignment), Flags(Flags), Entsize(Entsize), Type(Type),
         Link(Link), Info(Info) {}
 };
 
 // This corresponds to a section of an input file.
 class InputSectionBase : public SectionBase {
 public:
-  InputSectionBase()
-      : SectionBase(Regular, "", /*Flags*/ 0, /*Entsize*/ 0, /*Alignment*/ 0,
-                    /*Type*/ 0,
-                    /*Info*/ 0, /*Link*/ 0),
-        NumRelocations(0), AreRelocsRela(false), Repl(this) {}
-
   template <class ELFT>
   InputSectionBase(ObjFile<ELFT> *File, const typename ELFT::Shdr *Header,
                    StringRef Name, Kind SectionKind);
 
   InputSectionBase(InputFile *File, uint64_t Flags, uint32_t Type,
                    uint64_t Entsize, uint32_t Link, uint32_t Info,
                    uint32_t Alignment, ArrayRef<uint8_t> Data, StringRef Name,
                    Kind SectionKind);
 
   static bool classof(const SectionBase *S) { return S->kind() != Output; }
 
   // The file which contains this section. It's dynamic type is always
   // ObjFile<ELFT>, but in order to avoid ELFT, we use InputFile as
   // its static type.
   InputFile *File;
 
   template <class ELFT> ObjFile<ELFT> *getFile() const {
     return cast_or_null<ObjFile<ELFT>>(File);
   }
 
   ArrayRef<uint8_t> Data;
   uint64_t getOffsetInFile() const;
 
-  static InputSectionBase Discarded;
-
   // True if this section has already been placed to a linker script
   // output section. This is needed because, in a linker script, you
   // can refer to the same section more than once. For example, in
   // the following linker script,
   //
   //   .foo : { *(.text) }
   //   .bar : { *(.text) }
   //
public:
   void relocateNonAlloc(uint8_t *Buf, llvm::ArrayRef<RelTy> Rels);
 
   // Used by ICF.
   uint32_t Class[2] = {0, 0};
 
   // Called by ICF to merge two input sections.
   void replace(InputSection *Other);
 
+  static InputSection Discarded;
+
 private:
   template <class ELFT, class RelTy>
   void copyRelocations(uint8_t *Buf, llvm::ArrayRef<RelTy> Rels);
 
   template <class ELFT> void copyShtGroup(uint8_t *Buf);
 };
 
 // The list of all input sections.

ELF/InputSection.cpp

if (auto *D = dyn_cast<Defined>(B))
       if (D->Section == this && D->Value <= Off && Off < D->Value + D->Size)
         return Filename + ":(" + toString(*D) + ")" + Archive;
 
   // If there's no symbol, print out the offset in the section.
   return (Filename + ":(" + Name + "+0x" + utohexstr(Off) + ")" + Archive)
       .str();
 }
 
-InputSectionBase InputSectionBase::Discarded;
+InputSection InputSection::Discarded(0, 0, 0, ArrayRef<uint8_t>(), "");
 
 InputSection::InputSection(uint64_t Flags, uint32_t Type, uint32_t Alignment,
                            ArrayRef<uint8_t> Data, StringRef Name, Kind K)
     : InputSectionBase(nullptr, Flags, Type,
                        /*Entsize*/ 0, /*Link*/ 0, /*Info*/ 0, Alignment, Data,
                        Name, K) {}
 
 template <class ELFT>