[llvm-readobj] - Simplify .gnu.version_r dumping a bit.

[grimar]

Summary

.gnu.version_r was implemented by me in D21024.

Implementation takes "Number of needed versions" from DT_VERNEEDNUM
dynamic tag entry. Though it would be simpler to take it from sh_info section header field:
https://docs.oracle.com/cd/E19683-01/816-1386/chapter6-94076/index.html

[ruiu]

LGTM

llvm/trunk/tools/llvm-readobj/ELFDumper.cpp

static void printVersionDependencySection(ELFDumper<ELFT> *Dumper,
                                           ScopedPrinter &W) {
   using VerNeed = typename ELFO::Elf_Verneed;
   using VernAux = typename ELFO::Elf_Vernaux;
 
   DictScope SD(W, "SHT_GNU_verneed");
   if (!Sec)
     return;
 
-  unsigned VerNeedNum = 0;
-  for (const typename ELFO::Elf_Dyn &Dyn : Dumper->dynamic_table()) {
-    if (Dyn.d_tag == DT_VERNEEDNUM) {
-      VerNeedNum = Dyn.d_un.d_val;
-      break;
-    }
-  }
-
   const uint8_t *SecData = (const uint8_t *)Obj->base() + Sec->sh_offset;
   const typename ELFO::Elf_Shdr *StrTab =
       unwrapOrError(Obj->getSection(Sec->sh_link));
 
   const uint8_t *P = SecData;
+  unsigned VerNeedNum = Sec->sh_info;
   for (unsigned I = 0; I < VerNeedNum; ++I) {
     const VerNeed *Need = reinterpret_cast<const VerNeed *>(P);
     DictScope Entry(W, "Dependency");
     W.printNumber("Version", Need->vn_version);
     W.printNumber("Count", Need->vn_cnt);
     W.printString("FileName",
                   StringRef((const char *)(Obj->base() + StrTab->sh_offset +
                                            Need->vn_file)));