[NFC][llvm-readobj] Pull common code into a helper

[jhenderson]

Summary

This will make planned changes to this code easier to make.

[MaskRay]

Nice!

[grimar]

LGTM. Thoughs about possible futher refactoring is inline.

llvm/tools/llvm-readobj/ELFDumper.cpp

5445

A side note: I think we should probably get rid of First and pass the symbols index instead.
Seems First is used only for that purpose, but it is probably a bit confusing to see 2 Elf_Sym arguments
in a functions called like printSymbolSection, i.e. its name kind of assumes a single symbol, though arguments list has 2.

[grimar]

llvm/tools/llvm-readobj/ELFDumper.cpp

5448

To make the change above, this method and methods inside should be changed.

[jhenderson]

llvm/tools/llvm-readobj/ELFDumper.cpp

5448

I'm changing the getSectionNameIndex method in D69670 to split it up. Is that what you're referring to? Once that change lands, it might be possible to change the Object library getExtendedSymbolTableIndex interface to take an index, or I could change the new getSymbolSectionIndex function to figure out the value of First instead of passing it in.

[grimar]

llvm/tools/llvm-readobj/ELFDumper.cpp

5448

I'm changing the getSectionNameIndex method in D69670 to split it up. Is that what you're referring to?

No, I did not see D69670 when reviewed this one, but anyways I meant this and getExtendedSymbolTableIndex and may be something else will need a change to take an index if we deside to get rid of 'First'.

I think you can land your set of patches first and we can refactor this piece after that, as it is independent and unrelated actually.

llvm/tools/llvm-readobj/ELFDumper.cpp

public:
   void printMipsPLT(const MipsGOTParser<ELFT> &Parser) override;
   void printMipsABIFlags(const ELFObjectFile<ELFT> *Obj) override;
 
 private:
   void printRelocation(const ELFO *Obj, Elf_Rela Rel, const Elf_Shdr *SymTab);
   void printDynamicRelocation(const ELFO *Obj, Elf_Rela Rel);
   void printSymbols(const ELFO *Obj);
   void printDynamicSymbols(const ELFO *Obj);
+  void printSymbolSection(const Elf_Sym *Symbol, const Elf_Sym *First);
   void printSymbol(const ELFO *Obj, const Elf_Sym *Symbol, const Elf_Sym *First,
                    StringRef StrTable, bool IsDynamic,
                    bool /*NonVisibilityBitsUsed*/) override;
   void printProgramHeaders(const ELFO *Obj);
   void printSectionMapping(const ELFO *Obj) {}
 
   ScopedPrinter &W;
 };
if (opts::SectionData && Sec.sh_type != ELF::SHT_NOBITS) {
       W.printBinaryBlock(
           "SectionData",
           StringRef(reinterpret_cast<const char *>(Data.data()), Data.size()));
     }
   }
 }
 
 template <class ELFT>
+void LLVMStyle<ELFT>::printSymbolSection(const Elf_Sym *Symbol,
+                                         const Elf_Sym *First) {
+  unsigned SectionIndex = 0;
+  StringRef SectionName;
+  this->dumper()->getSectionNameIndex(Symbol, First, SectionName, SectionIndex);
+  W.printHex("Section", SectionName, SectionIndex);
+}
+
+template <class ELFT>
 void LLVMStyle<ELFT>::printSymbol(const ELFO *Obj, const Elf_Sym *Symbol,
                                   const Elf_Sym *First, StringRef StrTable,
                                   bool IsDynamic,
                                   bool /*NonVisibilityBitsUsed*/) {
-  unsigned SectionIndex = 0;
-  StringRef SectionName;
-  this->dumper()->getSectionNameIndex(Symbol, First, SectionName, SectionIndex);
   std::string FullSymbolName =
       this->dumper()->getFullSymbolName(Symbol, StrTable, IsDynamic);
   unsigned char SymbolType = Symbol->getType();
 
   DictScope D(W, "Symbol");
   W.printNumber("Name", FullSymbolName, Symbol->st_name);
   W.printHex("Value", Symbol->st_value);
   W.printNumber("Size", Symbol->st_size);
if (Obj->getHeader()->e_machine == EM_MIPS) {
                              std::end(ElfMips16SymOtherFlags));
       else
         SymOtherFlags.insert(SymOtherFlags.end(),
                              std::begin(ElfMipsSymOtherFlags),
                              std::end(ElfMipsSymOtherFlags));
     }
     W.printFlags("Other", Symbol->st_other, makeArrayRef(SymOtherFlags), 0x3u);
   }
-  W.printHex("Section", SectionName, SectionIndex);
+  printSymbolSection(Symbol, First);
 }
 
 template <class ELFT>
 void LLVMStyle<ELFT>::printSymbols(const ELFO *Obj, bool PrintSymbols,
                                    bool PrintDynamicSymbols) {
   if (PrintSymbols)
     printSymbols(Obj);
   if (PrintDynamicSymbols)
if (Parser.IsStatic)
     for (auto &E : Parser.getGlobalEntries()) {
       DictScope D(W, "Entry");
 
       PrintEntry(&E);
 
       const Elf_Sym *Sym = Parser.getGotSym(&E);
       W.printHex("Value", Sym->st_value);
       W.printEnum("Type", Sym->getType(), makeArrayRef(ElfSymbolTypes));
-
-      unsigned SectionIndex = 0;
-      StringRef SectionName;
-      this->dumper()->getSectionNameIndex(
-          Sym, this->dumper()->dynamic_symbols().begin(), SectionName,
-          SectionIndex);
-      W.printHex("Section", SectionName, SectionIndex);
+      printSymbolSection(Sym, this->dumper()->dynamic_symbols().begin());
 
       std::string SymName = this->dumper()->getFullSymbolName(
           Sym, this->dumper()->getDynamicStringTable(), true);
       W.printNumber("Name", SymName, Sym->st_name);
     }
   }
 
   W.printNumber("Number of TLS and multi-GOT entries",
DictScope GS(W, "PLT GOT");
     ListScope LS(W, "Entries");
     for (auto &E : Parser.getPltEntries()) {
       DictScope D(W, "Entry");
       PrintEntry(&E);
 
       const Elf_Sym *Sym = Parser.getPltSym(&E);
       W.printHex("Value", Sym->st_value);
       W.printEnum("Type", Sym->getType(), makeArrayRef(ElfSymbolTypes));
-
-      unsigned SectionIndex = 0;
-      StringRef SectionName;
-      this->dumper()->getSectionNameIndex(
-          Sym, this->dumper()->dynamic_symbols().begin(), SectionName,
-          SectionIndex);
-      W.printHex("Section", SectionName, SectionIndex);
+      printSymbolSection(Sym, this->dumper()->dynamic_symbols().begin());
 
       std::string SymName =
           this->dumper()->getFullSymbolName(Sym, Parser.getPltStrTable(), true);
       W.printNumber("Name", SymName, Sym->st_name);
     }
   }
 }