Fix the interpretation of a 0 st_name.

The ELF spec is very clear:

-----------------------------------------------------------------------------
If the value is non-zero, it represents a string table index that gives the
symbol name. Otherwise, the symbol table entry has no name.
--------------------------------------------------------------------------

In particular, a st_name of 0 most certainly doesn't mean that the symbol has
the same name as the section.

llvm-svn: 238899

1 files changed, 13 insertions, 9 deletions

diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 880143af712..8963c5e7032 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -705,26 +705,30 @@ void ELFDumper<ELFT>::printRelocation(const Elf_Shdr *Sec,
                                       typename ELFO::Elf_Rela Rel) {
   SmallString<32> RelocName;
   Obj->getRelocationTypeName(Rel.getType(Obj->isMips64EL()), RelocName);
-  StringRef SymbolName;
+  StringRef TargetName;
   std::pair<const Elf_Shdr *, const Elf_Sym *> Sym =
       Obj->getRelocationSymbol(Sec, &Rel);
-  if (Sym.first)
-    SymbolName = errorOrDefault(Obj->getSymbolName(Sym.first, Sym.second));
+  if (Sym.second && Sym.second->getType() == ELF::STT_SECTION) {
+    const Elf_Shdr *Sec = Obj->getSection(Sym.second);
+    ErrorOr<StringRef> SecName = Obj->getSectionName(Sec);
+    if (SecName)
+      TargetName = SecName.get();
+  } else if (Sym.first) {
+    TargetName = errorOrDefault(Obj->getSymbolName(Sym.first, Sym.second));
+  }
 
   if (opts::ExpandRelocs) {
     DictScope Group(W, "Relocation");
     W.printHex("Offset", Rel.r_offset);
     W.printNumber("Type", RelocName, (int)Rel.getType(Obj->isMips64EL()));
-    W.printNumber("Symbol", SymbolName.size() > 0 ? SymbolName : "-",
+    W.printNumber("Symbol", TargetName.size() > 0 ? TargetName : "-",
                   Rel.getSymbol(Obj->isMips64EL()));
     W.printHex("Addend", Rel.r_addend);
   } else {
     raw_ostream& OS = W.startLine();
-    OS << W.hex(Rel.r_offset)
-       << " " << RelocName
-       << " " << (SymbolName.size() > 0 ? SymbolName : "-")
-       << " " << W.hex(Rel.r_addend)
-       << "\n";
+    OS << W.hex(Rel.r_offset) << " " << RelocName << " "
+       << (TargetName.size() > 0 ? TargetName : "-") << " "
+       << W.hex(Rel.r_addend) << "\n";
   }
 }