[lld] [llvm] [llvm-readelf] Print more information for RELR (PR #89162)

[Fangrui Song via llvm-commits]

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@@ -3926,13 +3930,85 @@ template <class ELFT> void GNUELFDumper<ELFT>::printRelocations() {
     OS << "\nRelocation section '" << Name << "' at offset 0x"
        << utohexstr(Offset, /*LowerCase=*/true) << " contains " << EntriesNum
        << " entries:\n";
-    printRelocHeaderFields<ELFT>(OS, Sec.sh_type, this->Obj.getHeader());
-    this->printRelocationsHelper(Sec);
+
+    if (PrintAsRelr(Sec)) {
+      printRelr(Sec);
+    } else {
+      printRelocHeaderFields<ELFT>(OS, Sec.sh_type, this->Obj.getHeader());
+      this->printRelocationsHelper(Sec);
+    }
   }
   if (!HasRelocSections)
     OS << "\nThere are no relocations in this file.\n";
 }
 
+template <class ELFT> void GNUELFDumper<ELFT>::printRelr(const Elf_Shdr &Sec) {
+  Expected<Elf_Relr_Range> RangeOrErr = this->Obj.relrs(Sec);
+  if (!RangeOrErr) {
+    this->reportUniqueWarning("unable to read relocations from " +
+                              this->describe(Sec) + ": " +
+                              toString(RangeOrErr.takeError()));
+    return;
+  }
+  if (ELFT::Is64Bits)
+    OS << "Index: Entry            Address           Symbolic Address\n";
+  else
+    OS << "Index: Entry    Address   Symbolic Address\n";
+
+  SmallVector<std::pair<uint64_t, std::string>, 0> Syms;
+  if (this->DotSymtabSec) {
+    if (auto SymsOrErr = this->Obj.symbols(this->DotSymtabSec)) {
+      StringRef Strtab =
+          unwrapOrError(this->FileName,
+                        this->Obj.getStringTableForSymtab(*this->DotSymtabSec));
+      for (auto [I, Sym] : enumerate(*SymsOrErr)) {
+        Syms.emplace_back(Sym.st_value,
+                          this->getFullSymbolName(Sym, I, ArrayRef<Elf_Word>(),
+                                                  Strtab, false));
+      }
+    } else {
+      this->reportUniqueWarning(SymsOrErr.takeError());
+    }
+  }
+  llvm::stable_sort(Syms);
+
+  typename ELFT::uint Base = 0;
+  size_t I = 0;
+  auto Print = [&](uint64_t Where) {
+    OS << format_hex_no_prefix(Where, ELFT::Is64Bits ? 16 : 8);
+    for (; I < Syms.size() && Syms[I].first <= Where; ++I)
+      ;
+    if (I) {
+      OS << "  " << Syms[I - 1].second;
+      if (Syms[I - 1].first < Where)
+        OS << " + 0x" << Twine::utohexstr(Where - Syms[I - 1].first);
+    }
+    OS << '\n';
+  };
+  for (auto [I, R] : enumerate(*RangeOrErr)) {
----------------
MaskRay wrote:

Renamed to Index

https://github.com/llvm/llvm-project/pull/89162