[llvm-readobj] - Cleanup implementation LLVMStyle<ELFT>::printAddrsig().

[grimar]

Summary

It has following issues:

1. getStaticSymbolName returns std::string, but the code assigns a result to Expected<std::string>.
2. The code uses unwrapOrError and never tests the error reported.

This patch fixes these issues.

[MaskRay]

Looks great!

[jhenderson]

LGTM!

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

 
 ## Check that llvm-readobj dumps any SHT_LLVM_ADDRSIG section when --all
 ## is specified for LLVM style, but not for GNU style.
 ## TODO: Refine the llvm-readelf check when GNU-style dumping is implemented.
 
 # RUN: llvm-readobj --all %t1.o | FileCheck %s --check-prefix LLVM
 # RUN: llvm-readelf --all %t1.o 2>&1 | FileCheck %s --implicit-check-not=warning --implicit-check-not=error
 
-## Check we report a warning when SHT_LLVM_ADDRSIG is broken (e.g. contains a malformed uleb128).
+## Check we report a warning when the content of the SHT_LLVM_ADDRSIG section
+## is broken (e.g. contains a malformed uleb128).
 
-# RUN: yaml2obj --docnum=2 %s -o %t2.o
-# RUN: llvm-readobj --addrsig %t2.o 2>&1 | FileCheck %s -DFILE=%t2.o --check-prefix=MALFORMED
+# RUN: yaml2obj --docnum=2 %s -o %t2.1.o
+# RUN: llvm-readobj --addrsig %t2.1.o 2>&1 | FileCheck %s -DFILE=%t2.1.o --check-prefix=MALFORMED
 
-# MALFORMED: warning: '[[FILE]]': malformed uleb128, extends past end
+# MALFORMED:      Addrsig [
+# MALFORMED-NEXT: warning: '[[FILE]]': unable to decode SHT_LLVM_ADDRSIG section with index 1: malformed uleb128, extends past end
+# MALFORMED-NEXT: ]
 
 --- !ELF
 FileHeader:
   Class: ELFCLASS64
   Data:  ELFDATA2LSB
   Type:  ET_DYN
 Sections:
-  - Name: .llvm_addrsig
-    Type: SHT_LLVM_ADDRSIG
-    Content: "FF"
+  - Name:     .llvm_addrsig
+    Type:     SHT_LLVM_ADDRSIG
+    Content:  "FF"
+    ShOffset: [[OFFSET=<none>]]
+
+## Check we report a warning when the content of the SHT_LLVM_ADDRSIG section can't be read.
+
+# RUN: yaml2obj --docnum=2 -DOFFSET=0xffffffff %s -o %t2.2.o
+# RUN: llvm-readobj --addrsig %t2.2.o 2>&1 | FileCheck %s -DFILE=%t2.2.o --check-prefix=BROKEN-SEC
+
+# BROKEN-SEC:      Addrsig [
+# BROKEN-SEC-NEXT: warning: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x1) that is greater than the file size (0x168)
+# BROKEN-SEC-NEXT: ]
 
 ## Check we report a warning when SHT_LLVM_ADDRSIG references a symbol that can't be
 ## dumped (e.g. the index value is larger than the number of symbols in .symtab).
 
 # RUN: yaml2obj --docnum=3 %s -o %t3.o
 # RUN: llvm-readobj --addrsig %t3.o 2>&1 | FileCheck %s -DFILE=%t3.o --check-prefix=INVALID-INDEX
 
 # INVALID-INDEX:      Addrsig [

llvm/tools/llvm-readobj/ELFDumper.cpp

if (Err)
       return createError(Err);
     Cur += Size;
   }
   return Ret;
 }
 
 template <class ELFT> void LLVMStyle<ELFT>::printAddrsig() {
   ListScope L(W, "Addrsig");
-  if (!this->dumper()->getDotAddrsigSec())
+  const Elf_Shdr *Sec = this->dumper()->getDotAddrsigSec();
+  if (!Sec)
     return;
-  ArrayRef<uint8_t> Contents = unwrapOrError(
-      this->FileName,
-      this->Obj.getSectionContents(this->dumper()->getDotAddrsigSec()));
-  Expected<std::vector<uint64_t>> V = toULEB128Array(Contents);
-  if (!V) {
-    reportWarning(V.takeError(), this->FileName);
+
+  Expected<ArrayRef<uint8_t>> ContentsOrErr = this->Obj.getSectionContents(Sec);
+  if (!ContentsOrErr) {
+    this->reportUniqueWarning(ContentsOrErr.takeError());
     return;
   }
 
-  for (uint64_t Sym : *V) {
-    Expected<std::string> NameOrErr = this->dumper()->getStaticSymbolName(Sym);
-    if (NameOrErr) {
-      W.printNumber("Sym", *NameOrErr, Sym);
-      continue;
-    }
-    reportWarning(NameOrErr.takeError(), this->FileName);
-    W.printNumber("Sym", "<?>", Sym);
+  Expected<std::vector<uint64_t>> SymsOrErr = toULEB128Array(*ContentsOrErr);
+  if (!SymsOrErr) {
+    this->reportUniqueWarning(createError("unable to decode " +
+                                          describe(this->Obj, *Sec) + ": " +
+                                          toString(SymsOrErr.takeError())));
+    return;
   }
+
+  for (uint64_t Sym : *SymsOrErr)
+    W.printNumber("Sym", this->dumper()->getStaticSymbolName(Sym), Sym);
 }
 
 template <typename ELFT>
 static void printGNUNoteLLVMStyle(uint32_t NoteType, ArrayRef<uint8_t> Desc,
                                   ScopedPrinter &W) {
   switch (NoteType) {
   default:
     return;