Remove Elf_Sym_Iter.

It was a fairly broken concept for an ELF only class.

An ELF file can have two symbol tables, but they have exactly the same
format. There is no concept of a dynamic or a static symbol. Storing this
on the iterator also makes us do more work per symbol than necessary. To fetch
a name we would:

* Find if we had a static or a dynamic symbol.
* Look at the corresponding symbol table and find the string table section.
* Look at the string table section to fetch its contents.
* Compute the name as a substring of the string table.

All but the last step can be done per symbol table instead of per symbol. This
is a step in that direction.

llvm-svn: 240939

llvm/tools/llvm-objdump/llvm-objdump.cpp

@@ -321,6 +321,10 @@ static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
   const ELFFile<ELFT> &EF = *Obj->getELFFile();
 
   const Elf_Shdr *sec = EF.getSection(Rel.d.a);
+  const Elf_Shdr *SymTab = EF.getSection(sec->sh_link);
+  assert(SymTab->sh_type == ELF::SHT_SYMTAB ||
+         SymTab->sh_type == ELF::SHT_DYNSYM);
+  const Elf_Shdr *StrTab = EF.getSection(SymTab->sh_link);
   uint8_t type;
   StringRef res;
   int64_t addend = 0;
@@ -351,8 +355,7 @@ static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
       return EC;
     Target = *SecName;
   } else {
-    ErrorOr<StringRef> SymName =
-        EF.getSymbolName(EF.getSection(sec->sh_link), symb);
+    ErrorOr<StringRef> SymName = EF.getSymbolName(StrTab, symb);
     if (!SymName)
       return SymName.getError();
     Target = *SymName;