[llvm-readobj] - Stop using `unwrapOrError` in `DumpStyle<ELFT>::getGroups()`

[grimar]

Summary

With this we are able to diagnose possible issues much better and
don't exit on an error.

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/groups.test

135

The string table isn't directly linked to a group section, so I found the origianl message slightly confusing.

186

282

llvm/tools/llvm-readobj/ELFDumper.cpp

3572

I don't like this function name. It implies it is solely for use by errors, which isn't the case. How about getSectionNameOrFallback?

[grimar]

• Addressed review comments.

llvm/tools/llvm-readobj/ELFDumper.cpp

3572

Done. 2 more possible names probably are: getSectionNameOrWarn or tryGetSectionName.

[jhenderson]

LGTM.

llvm/test/tools/llvm-readobj/ELF/groups.test

186

Ping this?

llvm/tools/llvm-readobj/ELFDumper.cpp

3572

tryGetSectionName would work for me too. I'm happy with whichever you prefer. I'd probably not use getSectionNameOrWarn.

[grimar]

llvm/test/tools/llvm-readobj/ELF/groups.test

186

Will fix. Sorry!

llvm/test/tools/llvm-readobj/ELF/groups.test

 --- !ELF
 FileHeader:
   Class: ELFCLASS64
   Data:  ELFDATA2LSB
   Type:  ET_REL
 Sections:
   - Name: .group
     Type: SHT_GROUP
-    Link: .symtab
+    Link: [[SYMTAB1=.symtab]]
     Info: foo
     Members:
       - SectionOrType: GRP_COMDAT
       - SectionOrType: .text.foo
-      - SectionOrType: .rela.text.foo
+      - SectionOrType: [[MEMBER1=.rela.text.foo]]
+    ShSize: [[SECSIZE1=<none>]]
+    ShName: [[GROUP1SHNAME=<none>]]
   - Name: .group1
     Type: SHT_GROUP
-    Link: .symtab
+    Link: [[SYMTAB2=.symtab]]
     Info: bar
     Members:
       - SectionOrType: GRP_COMDAT
-      - SectionOrType: [[TEXTBARNAME=.text.bar]]
+      - SectionOrType: [[MEMBER2=.text.bar]]
       - SectionOrType: .rela.text.bar
+    ShSize: [[SECSIZE2=<none>]]
   - Name:  .text.foo
     Type:  SHT_PROGBITS
   - Name: .rela.text.foo
     Type: SHT_RELA
     Link: .symtab
     Info: .text.foo
-  - Name: .text.bar
-    Type: SHT_PROGBITS
+  - Name:   .text.bar
+    Type:   SHT_PROGBITS
+    ShName: [[TEXTBARSHNAME=<none>]]
   - Name: .rela.text.bar
     Type: SHT_RELA
     Link: .symtab
     Info: .text.bar
   - Name: .symtab
     Type: SHT_SYMTAB
     Link: [[SYMTABLINK=.strtab]]
 Symbols:
   - Name:    foo
     Section: .text.foo
   - Name:    bar
     Section: .text.bar
 
 ## Check that we report a warning and continue dumping when a section is included
 ## in two group sections at the same time.
 
-# RUN: yaml2obj %s -DTEXTBARNAME=.text.foo -o %t.dup.o
+# RUN: yaml2obj %s -DMEMBER2=.text.foo -o %t.dup.o
 # RUN: llvm-readobj --elf-section-groups %t.dup.o 2>&1 | FileCheck %s -DFILE=%t.dup.o --check-prefix=DUP-LLVM
 # RUN: llvm-readelf --elf-section-groups %t.dup.o 2>&1 | FileCheck %s -DFILE=%t.dup.o --check-prefix=DUP-GNU
 
 # DUP-LLVM:      Group {
 # DUP-LLVM-NEXT:   Name: .group
 # DUP-LLVM-NEXT:   Index: 1
 # DUP-LLVM-NEXT:   Link: 7
 # DUP-LLVM-NEXT:   Info: 1

 # DUP-GNU-NEXT:  [    4]   .rela.text.foo
 
 # DUP-GNU:      COMDAT group section [    2] `.group1' [bar] contains 2 sections:
 # DUP-GNU-NEXT:    [Index]    Name
 # DUP-GNU-NEXT: warning: '[[FILE]]': section with index 3, included in the group section with index 1, was also found in the group section with index 2
 # DUP-GNU-NEXT:    [    3]   .text.foo
 # DUP-GNU-NEXT:    [    6]   .rela.text.bar
 
+## Check what we do when we are unable to dump the signature symbol name.
+## In this case the index of the string table section, linked to group sections, is broken (section does not exist).
+## Check we report a warning in this case. Check we don't print the same warning message twice.
+
 # RUN: yaml2obj %s -DSYMTABLINK=0xFF -o %t.symtab.o
 # RUN: llvm-readobj --elf-section-groups %t.symtab.o 2>&1 | \
 # RUN:   FileCheck -DFILE=%t.symtab.o %s --check-prefix=SYMTAB-LLVM --implicit-check-not=warning:
 # RUN: llvm-readelf --elf-section-groups %t.symtab.o 2>&1 | \
 # RUN:   FileCheck -DFILE=%t.symtab.o %s --check-prefix=SYMTAB-GNU --implicit-check-not=warning:
 
 # SYMTAB-LLVM:      Groups {
 # SYMTAB-LLVM-NEXT: warning: '[[FILE]]': unable to get the string table for SHT_SYMTAB section with index 7: invalid section index: 255

 # SYMTAB-GNU-NEXT:      [Index]    Name
 # SYMTAB-GNU-NEXT:      [    3]   .text.foo
 # SYMTAB-GNU-NEXT:      [    4]   .rela.text.foo
 # SYMTAB-GNU-EMPTY:
 # SYMTAB-GNU-NEXT:   COMDAT group section [    2] `.group1' [<?>] contains 2 sections:
 # SYMTAB-GNU-NEXT:      [Index]    Name
 # SYMTAB-GNU-NEXT:      [    5]   .text.bar
 # SYMTAB-GNU-NEXT:      [    6]   .rela.text.bar
+
+## This tests the behavior for two more cases when we are unable to dump the signature symbol name.
+## In the first case we link the group section to the section with index 255, which does not exist.
+## We check that the warning is reported when we are unable to locate the symbol table.
+## In the second case we link the SHT_GROUP section to itself. This documents that we don't check the
+## type of the linked section (we assume it is the symbol table) and checks that we report a warning
+## when we are unable to read a signature symbol.
+
+# RUN: yaml2obj %s -DSYMTAB1=0xFF -DSYMTAB2=0x1 -o %t.symtab2.o
+# RUN: llvm-readobj --elf-section-groups %t.symtab2.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.symtab2.o %s --check-prefix=SIGNATURE-LLVM --implicit-check-not=warning:
+# RUN: llvm-readelf --elf-section-groups %t.symtab2.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.symtab2.o %s --check-prefix=SIGNATURE-GNU --implicit-check-not=warning:
+
+# SIGNATURE:      Groups {
+# SIGNATURE-LLVM: warning: '[[FILE]]': unable to get the symbol table for SHT_GROUP section with index 1: invalid section index: 255
+# SIGNATURE-LLVM: warning: '[[FILE]]': unable to get the signature symbol for SHT_GROUP section with index 2: section [index 1] has invalid sh_entsize: expected 24, but got 4
+# SIGNATURE-LLVM:   Group {
+# SIGNATURE-LLVM:     Name: .group (16)
+# SIGNATURE-LLVM:     Index: 1
+# SIGNATURE-LLVM:     Link: 255
+# SIGNATURE-LLVM:     Info: 1
+# SIGNATURE-LLVM:     Type: COMDAT (0x1)
+# SIGNATURE-LLVM:     Signature: <?>
+# SIGNATURE-LLVM:     Section(s) in group [
+# SIGNATURE-LLVM:       .text.foo (3)
+# SIGNATURE-LLVM:       .rela.text.foo (4)
+# SIGNATURE-LLVM:     ]
+# SIGNATURE-LLVM:   }
+# SIGNATURE-LLVM:   Group {
+# SIGNATURE-LLVM:     Name: .group1 (64)
+# SIGNATURE-LLVM:     Index: 2
+# SIGNATURE-LLVM:     Link: 1
+# SIGNATURE-LLVM:     Info: 2
+# SIGNATURE-LLVM:     Type: COMDAT (0x1)
+# SIGNATURE-LLVM:     Signature: <?>
+# SIGNATURE-LLVM:     Section(s) in group [
+# SIGNATURE-LLVM:       .text.bar (5)
+# SIGNATURE-LLVM:       .rela.text.bar (6)
+# SIGNATURE-LLVM:     ]
+# SIGNATURE-LLVM:   }
+# SIGNATURE-LLVM: }
+
+# SIGNATURE-GNU:       warning: '[[FILE]]': unable to get the symbol table for SHT_GROUP section with index 1: invalid section index: 255
+# SIGNATURE-GNU-NEXT:  warning: '[[FILE]]': unable to get the signature symbol for SHT_GROUP section with index 2: section [index 1] has invalid sh_entsize: expected 24, but got 4
+# SIGNATURE-GNU-EMPTY:
+# SIGNATURE-GNU-NEXT:  COMDAT group section [    1] `.group' [<?>] contains 2 sections:
+# SIGNATURE-GNU-NEXT:     [Index]    Name
+# SIGNATURE-GNU-NEXT:     [    3]   .text.foo
+# SIGNATURE-GNU-NEXT:     [    4]   .rela.text.foo
+# SIGNATURE-GNU-EMPTY:
+# SIGNATURE-GNU-NEXT:  COMDAT group section [    2] `.group1' [<?>] contains 2 sections:
+# SIGNATURE-GNU-NEXT:     [Index]    Name
+# SIGNATURE-GNU-NEXT:     [    5]   .text.bar
+# SIGNATURE-GNU-NEXT:     [    6]   .rela.text.bar
+
+## Check we report a warning when the content of the group section is empty or can't be read.
+## In both cases we are unable to read the section group flag and dump it as 0.
+
+# RUN: yaml2obj %s -DSECSIZE1=0x0 -DSECSIZE2=0x1 -o %t.secsize.o
+# RUN: llvm-readobj --elf-section-groups %t.secsize.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.secsize.o %s --check-prefix=CONTENT-LLVM --implicit-check-not=warning:
+# RUN: llvm-readelf --elf-section-groups %t.secsize.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.secsize.o %s --check-prefix=CONTENT-GNU --implicit-check-not=warning:
+
+# CONTENT-LLVM:      Groups {
+# CONTENT-LLVM-NEXT: warning: '[[FILE]]': unable to read the section group flag from the SHT_GROUP section with index 1: the section is empty
+# CONTENT-LLVM-NEXT: warning: '[[FILE]]': unable to get the content of the SHT_GROUP section with index 2: section [index 2] has an invalid sh_size (1) which is not a multiple of its sh_entsize (4)
+# CONTENT-LLVM-NEXT:   Group {
+# CONTENT-LLVM-NEXT:     Name: .group (16)
+# CONTENT-LLVM-NEXT:     Index: 1
+# CONTENT-LLVM-NEXT:     Link: 7
+# CONTENT-LLVM-NEXT:     Info: 1
+# CONTENT-LLVM-NEXT:     Type: (unknown) (0x0)
+# CONTENT-LLVM-NEXT:     Signature: foo
+# CONTENT-LLVM-NEXT:     Section(s) in group [
+# CONTENT-LLVM-NEXT:     ]
+# CONTENT-LLVM-NEXT:   }
+# CONTENT-LLVM-NEXT:   Group {
+# CONTENT-LLVM-NEXT:     Name: .group1 (64)
+# CONTENT-LLVM-NEXT:     Index: 2
+# CONTENT-LLVM-NEXT:     Link: 7
+# CONTENT-LLVM-NEXT:     Info: 2
+# CONTENT-LLVM-NEXT:     Type: (unknown) (0x0)
+# CONTENT-LLVM-NEXT:     Signature: bar
+# CONTENT-LLVM-NEXT:     Section(s) in group [
+# CONTENT-LLVM-NEXT:     ]
+# CONTENT-LLVM-NEXT:   }
+# CONTENT-LLVM-NEXT: }
+
+# CONTENT-GNU:       warning: '[[FILE]]': unable to read the section group flag from the SHT_GROUP section with index 1: the section is empty
+# CONTENT-GNU:       warning: '[[FILE]]': unable to get the content of the SHT_GROUP section with index 2: section [index 2] has an invalid sh_size (1) which is not a multiple of its sh_entsize (4)
+# CONTENT-GNU-EMPTY:
+# CONTENT-GNU-NEXT:  (unknown) group section [    1] `.group' [foo] contains 0 sections:
+# CONTENT-GNU-NEXT:    [Index]    Name
+# CONTENT-GNU-EMPTY:
+# CONTENT-GNU-NEXT:  (unknown) group section [    2] `.group1' [bar] contains 0 sections:
+# CONTENT-GNU-NEXT:    [Index]    Name
+
+## Check that we a warning when we are unable to read the group section name or the name of a member.
+
+# RUN: yaml2obj %s -DGROUP1SHNAME=0xAAAA -DTEXTBARSHNAME=0xBBBB -o %t.name.o
+# RUN: llvm-readobj --elf-section-groups %t.name.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.name.o %s --check-prefix=NAME-LLVM --implicit-check-not=warning:
+# RUN: llvm-readelf --elf-section-groups %t.name.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.name.o %s --check-prefix=NAME-GNU --implicit-check-not=warning:
+
+# NAME-LLVM:      Groups {
+# NAME-LLVM-NEXT: warning: '[[FILE]]': unable to get the name of the SHT_GROUP section with index 1: a section [index 1] has an invalid sh_name (0xaaaa) offset which goes past the end of the section name string table
+# NAME-LLVM-NEXT: warning: '[[FILE]]': unable to get the name of the SHT_PROGBITS section with index 5: a section [index 5] has an invalid sh_name (0xbbbb) offset which goes past the end of the section name string table
+# NAME-LLVM-NEXT:   Group {
+# NAME-LLVM-NEXT:     Name: <?> (43690)
+# NAME-LLVM-NEXT:     Index: 1
+# NAME-LLVM-NEXT:     Link: 7
+# NAME-LLVM-NEXT:     Info: 1
+# NAME-LLVM-NEXT:     Type: COMDAT (0x1)
+# NAME-LLVM-NEXT:     Signature: foo
+# NAME-LLVM-NEXT:     Section(s) in group [
+# NAME-LLVM-NEXT:       .text.foo (3)
+# NAME-LLVM-NEXT:       .rela.text.foo (4)
+# NAME-LLVM-NEXT:     ]
+# NAME-LLVM-NEXT:   }
+# NAME-LLVM-NEXT:   Group {
+# NAME-LLVM-NEXT:     Name: .group1 (64)
+# NAME-LLVM-NEXT:     Index: 2
+# NAME-LLVM-NEXT:     Link: 7
+# NAME-LLVM-NEXT:     Info: 2
+# NAME-LLVM-NEXT:     Type: COMDAT (0x1)
+# NAME-LLVM-NEXT:     Signature: bar
+# NAME-LLVM-NEXT:     Section(s) in group [
+# NAME-LLVM-NEXT:       <?> (5)
+# NAME-LLVM-NEXT:       .rela.text.bar (6)
+# NAME-LLVM-NEXT:     ]
+# NAME-LLVM-NEXT:   }
+# NAME-LLVM-NEXT: }
+
+# NAME-GNU:        warning: '[[FILE]]': unable to get the name of the SHT_GROUP section with index 1: a section [index 1] has an invalid sh_name (0xaaaa) offset which goes past the end of the section name string table
+# NAME-GNU-NEXT:   warning: '[[FILE]]': unable to get the name of the SHT_PROGBITS section with index 5: a section [index 5] has an invalid sh_name (0xbbbb) offset which goes past the end of the section name string table
+# NAME-GNU-EMPTY:
+# NAME-GNU-NEXT:   COMDAT group section [    1] `<?>' [foo] contains 2 sections:
+# NAME-GNU-NEXT:      [Index]    Name
+# NAME-GNU-NEXT:      [    3]   .text.foo
+# NAME-GNU-NEXT:      [    4]   .rela.text.foo
+# NAME-GNU-EMPTY:
+# NAME-GNU-NEXT:  COMDAT group section [    2] `.group1' [bar] contains 2 sections:
+# NAME-GNU-NEXT:     [Index]    Name
+# NAME-GNU-NEXT:     [    5]   <?>
+# NAME-GNU-NEXT:     [    6]   .rela.text.bar
+
+## Check we report a warning then the section index of a section group member is invalid.
+
+# RUN: yaml2obj %s -DMEMBER1=0xEE -DMEMBER2=0xFF -o %t.member.index.o
+# RUN: llvm-readobj --elf-section-groups %t.member.index.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.member.index.o %s --check-prefix=MEMBER-LLVM --implicit-check-not=warning:
+# RUN: llvm-readelf --elf-section-groups %t.member.index.o 2>&1 | \
+# RUN:   FileCheck -DFILE=%t.member.index.o %s --check-prefix=MEMBER-GNU --implicit-check-not=warning:
+
+# MEMBER-LLVM:      Groups {
+# MEMBER-LLVM-NEXT: warning: '[[FILE]]': unable to get the section with index 238 when dumping the SHT_GROUP section with index 1: invalid section index: 238
+# MEMBER-LLVM-NEXT: warning: '[[FILE]]': unable to get the section with index 255 when dumping the SHT_GROUP section with index 2: invalid section index: 255
+# MEMBER-LLVM-NEXT:   Group {
+# MEMBER-LLVM-NEXT:     Name: .group (16)
+# MEMBER-LLVM-NEXT:     Index: 1
+# MEMBER-LLVM-NEXT:     Link: 7
+# MEMBER-LLVM-NEXT:     Info: 1
+# MEMBER-LLVM-NEXT:     Type: COMDAT (0x1)
+# MEMBER-LLVM-NEXT:     Signature: foo
+# MEMBER-LLVM-NEXT:     Section(s) in group [
+# MEMBER-LLVM-NEXT:       .text.foo (3)
+# MEMBER-LLVM-NEXT:       <?> (238)
+# MEMBER-LLVM-NEXT:     ]
+# MEMBER-LLVM-NEXT:   }
+# MEMBER-LLVM-NEXT:   Group {
+# MEMBER-LLVM-NEXT:     Name: .group1 (64)
+# MEMBER-LLVM-NEXT:     Index: 2
+# MEMBER-LLVM-NEXT:     Link: 7
+# MEMBER-LLVM-NEXT:     Info: 2
+# MEMBER-LLVM-NEXT:     Type: COMDAT (0x1)
+# MEMBER-LLVM-NEXT:     Signature: bar
+# MEMBER-LLVM-NEXT:     Section(s) in group [
+# MEMBER-LLVM-NEXT:       <?> (255)
+# MEMBER-LLVM-NEXT:       .rela.text.bar (6)
+# MEMBER-LLVM-NEXT:     ]
+# MEMBER-LLVM-NEXT:   }
+# MEMBER-LLVM-NEXT: }
+
+# MEMBER-GNU:       warning: '[[FILE]]': unable to get the section with index 238 when dumping the SHT_GROUP section with index 1: invalid section index: 238
+# MEMBER-GNU-NEXT:  warning: '[[FILE]]': unable to get the section with index 255 when dumping the SHT_GROUP section with index 2: invalid section index: 255
+# MEMBER-GNU-EMPTY:
+# MEMBER-GNU-NEXT:  COMDAT group section [    1] `.group' [foo] contains 2 sections:
+# MEMBER-GNU-NEXT:     [Index]    Name
+# MEMBER-GNU-NEXT:     [    3]   .text.foo
+# MEMBER-GNU-NEXT:     [  238]   <?>
+# MEMBER-GNU-EMPTY:
+# MEMBER-GNU-NEXT:  COMDAT group section [    2] `.group1' [bar] contains 2 sections:
+# MEMBER-GNU-NEXT:     [Index]    Name
+# MEMBER-GNU-NEXT:     [  255]   <?>
+# MEMBER-GNU-NEXT:     [    6]   .rela.text.bar

llvm/tools/llvm-readobj/ELFDumper.cpp

public:
   void printStackSize(RelocationRef Rel, const Elf_Shdr *FunctionSec,
                       const Elf_Shdr &StackSizeSec,
                       const RelocationResolver &Resolver, DataExtractor Data);
   virtual void printStackSizeEntry(uint64_t Size, StringRef FuncName) = 0;
   virtual void printMipsGOT(const MipsGOTParser<ELFT> &Parser) = 0;
   virtual void printMipsPLT(const MipsGOTParser<ELFT> &Parser) = 0;
   virtual void printMipsABIFlags() = 0;
   const ELFDumper<ELFT> &dumper() const { return Dumper; }
+  void reportUniqueWarning(Error Err) const;
 
 protected:
   std::vector<GroupSection> getGroups();
 
   void printDependentLibsHelper(
       function_ref<void(const Elf_Shdr &)> OnSectionStart,
       function_ref<void(StringRef, uint64_t)> OnSectionEntry);
 
void forEachRelocationDo(
       llvm::function_ref<void(const Elf_Relr &)> RelrFn);
   void printRelocationsHelper(const Elf_Shdr &Sec);
   void printDynamicRelocationsHelper();
   virtual void printDynamicRelocHeader(unsigned Type, StringRef Name,
                                        const DynRegionInfo &Reg){};
 
   StringRef getPrintableSectionName(const Elf_Shdr &Sec) const;
 
-  void reportUniqueWarning(Error Err) const;
-
   StringRef FileName;
   const ELFFile<ELFT> &Obj;
   const ELFObjectFile<ELFT> &ElfObj;
 
 private:
   const ELFDumper<ELFT> &Dumper;
 };
 
template <class ELFT> void GNUStyle<ELFT>::printFileHeaders() {
   Str = to_string(e.e_shentsize) + " (bytes)";
   printFields(OS, "Size of section headers:", Str);
   Str = getSectionHeadersNumString(this->Obj, this->FileName);
   printFields(OS, "Number of section headers:", Str);
   Str = getSectionHeaderTableIndexString(this->Obj, this->FileName);
   printFields(OS, "Section header string table index:", Str);
 }
 
+template <class ELFT>
+static StringRef getSectionNameForError(const ELFFile<ELFT> &Obj,
+                                        const typename ELFT::Shdr &Sec,
+                                        DumpStyle<ELFT> &Dump) {
+  if (Expected<StringRef> SecNameOrErr = Obj.getSectionName(Sec))
+    return *SecNameOrErr;
+  else
+    Dump.reportUniqueWarning(createError("unable to get the name of the " +
+                                         describe(Obj, Sec) + ": " +
+                                         toString(SecNameOrErr.takeError())));
+  return "<?>";
+}
+
 template <class ELFT> std::vector<GroupSection> DumpStyle<ELFT>::getGroups() {
   auto GetSignature = [&](const Elf_Sym &Sym,
                           const Elf_Shdr &Symtab) -> StringRef {
     Expected<StringRef> StrTableOrErr = Obj.getStringTableForSymtab(Symtab);
     if (!StrTableOrErr) {
       reportUniqueWarning(createError("unable to get the string table for " +
                                       describe(Obj, Symtab) + ": " +
                                       toString(StrTableOrErr.takeError())));
       return "<?>";
     }
 
     // TODO: this might lead to a crash or produce a wrong result, when the
     // st_name goes past the end of the string table.
     return StrTableOrErr->data() + Sym.st_name;
   };
 
   std::vector<GroupSection> Ret;
   uint64_t I = 0;
   for (const Elf_Shdr &Sec : cantFail(Obj.sections())) {
     ++I;
     if (Sec.sh_type != ELF::SHT_GROUP)
       continue;
 
-    const Elf_Shdr *Symtab =
-        unwrapOrError(FileName, Obj.getSection(Sec.sh_link));
+    StringRef Signature = "<?>";
+    if (Expected<const Elf_Shdr *> SymtabOrErr = Obj.getSection(Sec.sh_link)) {
+      if (Expected<const Elf_Sym *> SymOrErr =
+              Obj.template getEntry<Elf_Sym>(**SymtabOrErr, Sec.sh_info))
+        Signature = GetSignature(**SymOrErr, **SymtabOrErr);
+      else
+        reportUniqueWarning(createError(
+            "unable to get the signature symbol for " + describe(Obj, Sec) +
+            ": " + toString(SymOrErr.takeError())));
+    } else {
+      reportUniqueWarning(createError("unable to get the symbol table for " +
+                                      describe(Obj, Sec) + ": " +
+                                      toString(SymtabOrErr.takeError())));
+    }
+
+    ArrayRef<Elf_Word> Data;
+    if (Expected<ArrayRef<Elf_Word>> ContentsOrErr =
+            Obj.template getSectionContentsAsArray<Elf_Word>(Sec)) {
+      if (ContentsOrErr->empty())
+        reportUniqueWarning(
+            createError("unable to read the section group flag from the " +
+                        describe(Obj, Sec) + ": the section is empty"));
+      else
+        Data = *ContentsOrErr;
+    } else {
+      reportUniqueWarning(createError("unable to get the content of the " +
+                                      describe(Obj, Sec) + ": " +
+                                      toString(ContentsOrErr.takeError())));
+    }
 
-    const Elf_Sym *Sym = unwrapOrError(
-        FileName, Obj.template getEntry<Elf_Sym>(*Symtab, Sec.sh_info));
-    auto Data = unwrapOrError(
-        FileName, Obj.template getSectionContentsAsArray<Elf_Word>(Sec));
-
-    StringRef Name = unwrapOrError(FileName, Obj.getSectionName(Sec));
-    StringRef Signature = GetSignature(*Sym, *Symtab);
-    Ret.push_back({Name,
+    Ret.push_back({getSectionNameForError(Obj, Sec, *this),
                    maybeDemangle(Signature),
                    Sec.sh_name,
                    I - 1,
                    Sec.sh_link,
                    Sec.sh_info,
-                   Data[0],
+                   Data.empty() ? Elf_Word(0) : Data[0],
                    {}});
 
+    if (Data.empty())
+      continue;
+
     std::vector<GroupMember> &GM = Ret.back().Members;
     for (uint32_t Ndx : Data.slice(1)) {
-      const Elf_Shdr &Sec = *unwrapOrError(FileName, Obj.getSection(Ndx));
-      const StringRef Name = unwrapOrError(FileName, Obj.getSectionName(Sec));
-      GM.push_back({Name, Ndx});
+      if (Expected<const Elf_Shdr *> SecOrErr = Obj.getSection(Ndx)) {
+        GM.push_back({getSectionNameForError(Obj, **SecOrErr, *this), Ndx});
+      } else {
+        reportUniqueWarning(
+            createError("unable to get the section with index " + Twine(Ndx) +
+                        " when dumping the " + describe(Obj, Sec) + ": " +
+                        toString(SecOrErr.takeError())));
+        GM.push_back({"<?>", Ndx});
+      }
     }
   }
   return Ret;
 }
 
 static DenseMap<uint64_t, const GroupSection *>
 mapSectionsToGroups(ArrayRef<GroupSection> Groups) {
   DenseMap<uint64_t, const GroupSection *> Ret;