[llvm-readelf] - Stop using 'unwrapOrError()' in 'ELFDumper<ELFT>::getSymbolVersion'.

[grimar]

Summary

This allows to propagate an error and report a warning properly.

[MaskRay]

LGTM.

[jhenderson]

LGTM too.

llvm/test/tools/llvm-readobj/ELF/versym-invalid.test

Sections:
   - Name:    .gnu.version
     Type:    SHT_GNU_versym
     Entries: [ ]
     ShOffset: 0xffff
 
 ## Check we report a warning when a SHT_GNU_versym section has an invalid entry size.
 
 # RUN: yaml2obj --docnum=5 %s -o %t5
-# RUN: llvm-readelf -V %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-GNU
-# RUN: llvm-readobj -V %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-LLVM
+# RUN: llvm-readelf -V --dyn-syms %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-GNU
+# RUN: llvm-readobj -V --dyn-syms %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-LLVM
 
+# INVALID-ENT-SIZE-GNU:      Symbol table '.dynsym' contains 2 entries:
+# INVALID-ENT-SIZE-GNU-NEXT:    Num:    Value          Size Type    Bind   Vis       Ndx Name
+# INVALID-ENT-SIZE-GNU-NEXT: warning: '[[FILE]]': section [index 1] has invalid sh_entsize: expected 2, but got 3
+# INVALID-ENT-SIZE-GNU-NEXT:      0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT   UND @<corrupt>
+# INVALID-ENT-SIZE-GNU-NEXT:      1: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT   UND foo@<corrupt>
 # INVALID-ENT-SIZE-GNU:      Version symbols section '.gnu.version' contains 1 entries:
 # INVALID-ENT-SIZE-GNU-NEXT:  Addr: 0000000000000000  Offset: 0x000040  Link: 0 ()
 # INVALID-ENT-SIZE-GNU-NEXT: warning: '[[FILE]]': cannot read content of SHT_GNU_versym section with index 1: section [index 1] has an invalid sh_entsize: 3
 
+# INVALID-ENT-SIZE-LLVM:      DynamicSymbols [
+# INVALID-ENT-SIZE-LLVM-NEXT: warning: '[[FILE]]': section [index 1] has invalid sh_entsize: expected 2, but got 3
+# INVALID-ENT-SIZE-LLVM-NEXT:   Symbol {
+# INVALID-ENT-SIZE-LLVM-NEXT:     Name: @<corrupt> (0)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Value: 0x0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Size: 0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Binding: Local (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Type: None (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Other: 0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Section: Undefined (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:   }
+# INVALID-ENT-SIZE-LLVM-NEXT:   Symbol {
+# INVALID-ENT-SIZE-LLVM-NEXT:     Name: foo@<corrupt> (1)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Value: 0x0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Size: 0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Binding: Local (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Type: None (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:     Other: 0
+# INVALID-ENT-SIZE-LLVM-NEXT:     Section: Undefined (0x0)
+# INVALID-ENT-SIZE-LLVM-NEXT:   }
+# INVALID-ENT-SIZE-LLVM-NEXT: ]
 # INVALID-ENT-SIZE-LLVM:      VersionSymbols [
 # INVALID-ENT-SIZE-LLVM-NEXT: warning: '[[FILE]]': cannot read content of SHT_GNU_versym section with index 1: section [index 1] has an invalid sh_entsize: 3
 # INVALID-ENT-SIZE-LLVM-NEXT: ]
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_EXEC
   Machine: EM_X86_64
 Sections:
   - Name:    .gnu.version
     Type:    SHT_GNU_versym
     Entries: [ 0 ]
     EntSize: 3
+DynamicSymbols:
+  - Name: foo
 
 ## Check we report a warning when the number of version entries does not match the number of symbols in the associated symbol table.
 
 # RUN: yaml2obj --docnum=6 %s -o %t6
 # RUN: llvm-readelf -V %t6 2>&1 | FileCheck -DFILE=%t6 %s --check-prefix=SYMBOLS-NUM-MISMATCH-GNU
 # RUN: llvm-readobj -V %t6 2>&1 | FileCheck -DFILE=%t6 %s --check-prefix=SYMBOLS-NUM-MISMATCH-LLVM
 
 # SYMBOLS-NUM-MISMATCH-GNU:      Version symbols section '.gnu.version' contains 2 entries:

llvm/tools/llvm-readobj/ELFDumper.cpp

Expected<StringRef> ELFDumper<ELFT>::getSymbolVersion(const Elf_Sym *Sym,
 
   assert(DynSymRegion && "DynSymRegion has not been initialised");
   // Determine the position in the symbol table of this entry.
   size_t EntryIndex = (reinterpret_cast<uintptr_t>(Sym) -
                        reinterpret_cast<uintptr_t>(DynSymRegion->Addr)) /
                       sizeof(Elf_Sym);
 
   // Get the corresponding version index entry.
-  const Elf_Versym *Versym = unwrapOrError(
-      ObjF->getFileName(), ObjF->getELFFile()->template getEntry<Elf_Versym>(
-                               SymbolVersionSection, EntryIndex));
-  return this->getSymbolVersionByIndex(Versym->vs_index, IsDefault);
+  if (Expected<const Elf_Versym *> EntryOrErr =
+          ObjF->getELFFile()->template getEntry<Elf_Versym>(
+              SymbolVersionSection, EntryIndex))
+    return this->getSymbolVersionByIndex((*EntryOrErr)->vs_index, IsDefault);
+  else
+    return EntryOrErr.takeError();
 }
 
 template <typename ELFT>
 Expected<std::pair<const typename ELFT::Sym *, std::string>>
 ELFDumper<ELFT>::getRelocationTarget(const Elf_Shdr *SymTab,
                                      const Elf_Rela &R) const {
   const ELFFile<ELFT> *Obj = ObjF->getELFFile();
   Expected<const Elf_Sym *> SymOrErr = Obj->getRelocationSymbol(&R, SymTab);