[llvm-readobj] - Remove unwrapOrError calls from GNUStyle<ELFT>::printRelocations.

[grimar]

Summary

This fixes existent FIXMEs: we should not error out when unable to
find the number of relocations.

[MaskRay]

LGTM.

[jhenderson]

LGTM too.

llvm/test/tools/llvm-readobj/ELF/packed-relocs.test

- Name:    sym1
     Binding: STB_GLOBAL
   - Name:    sym2
     Binding: STB_GLOBAL
 
 ## Check we report a warning when we are unable to dump relocations for a SHT_ANDROID_RELA section.
 
 # RUN: yaml2obj --docnum=1 -DSHOFFSET=0xffffffff %s -o %t1.broken
 # RUN: llvm-readobj --relocations %t1.broken 2>&1 | FileCheck -DFILE=%t1.broken --check-prefix=BROKEN-RELA-LLVM %s
-# RUN: not llvm-readelf --relocations %t1.broken 2>&1 | FileCheck -DFILE=%t1.broken --check-prefix=BROKEN-RELA-GNU %s
+# RUN: llvm-readelf --relocations %t1.broken 2>&1 | FileCheck -DFILE=%t1.broken --check-prefix=BROKEN-RELA-GNU %s
 
 # BROKEN-RELA-LLVM:      Relocations [
 # BROKEN-RELA-LLVM-NEXT:   Section (1) .rela.dyn {
 # BROKEN-RELA-LLVM-NEXT: warning: '[[FILE]]': unable to read relocations from SHT_ANDROID_RELA section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x3a) that is greater than the file size (0x238)
 # BROKEN-RELA-LLVM-NEXT:   }
 # BROKEN-RELA-LLVM-NEXT: ]
 
-## FIXME: GNU still reports an error before trying to dump relocations.
-# BROKEN-RELA-GNU: error: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x3a) that is greater than the file size (0x238)
+# BROKEN-RELA-GNU:      warning: '[[FILE]]': unable to get the number of relocations in SHT_ANDROID_RELA section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x3a) that is greater than the file size (0x238)
+# BROKEN-RELA-GNU:      Relocation section '.rela.dyn' at offset 0xffffffff contains <?> entries:
+# BROKEN-RELA-GNU-NEXT:     Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
+# BROKEN-RELA-GNU-NEXT: warning: '[[FILE]]': unable to read relocations from SHT_ANDROID_RELA section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x3a) that is greater than the file size (0x238)
 
 ## Check we report a warning when the sh_link field of the SHT_ANDROID_RELA section is broken.
 
 # RUN: yaml2obj --docnum=1 -DLINK=0xffffffff %s -o %t1.broken.link
 # RUN: llvm-readobj --relocations %t1.broken.link 2>&1 | \
 # RUN:   FileCheck -DFILE=%t1.broken.link --check-prefix=BROKEN-RELA-LINK-LLVM %s
 # RUN: llvm-readelf --relocations %t1.broken.link 2>&1 | \
 # RUN:   FileCheck -DFILE=%t1.broken.link --check-prefix=BROKEN-RELA-LINK-GNU %s
- Name:    sym1
     Binding: STB_GLOBAL
   - Name:    sym2
     Binding: STB_GLOBAL
 
 ## Check we report a warning when we are unable to dump relocations for a SHT_ANDROID_REL section.
 
 # RUN: yaml2obj --docnum=2 -DSHOFFSET=0xffffffff %s -o %t2.broken
 # RUN: llvm-readobj --relocations %t2.broken 2>&1 | FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-REL-LLVM %s
-# RUN: not llvm-readelf --relocations %t2.broken 2>&1 | FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-REL-GNU %s
+# RUN: llvm-readelf --relocations %t2.broken 2>&1 | FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-REL-GNU %s
 
 # BROKEN-REL-LLVM:      Relocations [
 # BROKEN-REL-LLVM-NEXT:   Section (1) .rel.dyn {
 # BROKEN-REL-LLVM-NEXT: warning: '[[FILE]]': unable to read relocations from SHT_ANDROID_REL section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x12) that cannot be represented
 # BROKEN-REL-LLVM-NEXT:   }
 # BROKEN-REL-LLVM-NEXT: ]
 
-## FIXME: GNU still reports an error before trying to dump relocations.
-# BROKEN-REL-GNU: error: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x12) that cannot be represented
+# BROKEN-REL-GNU:      warning: '[[FILE]]': unable to get the number of relocations in SHT_ANDROID_REL section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x12) that cannot be represented
+# BROKEN-REL-GNU:      Relocation section '.rel.dyn' at offset 0xffffffff contains <?> entries:
+# BROKEN-REL-GNU-NEXT:  Offset     Info    Type                Sym. Value  Symbol's Name
+# BROKEN-REL-GNU-NEXT: warning: '[[FILE]]': unable to read relocations from SHT_ANDROID_REL section with index 1: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x12) that cannot be represented
 
 ## Check we report a warning when the sh_link field of the SHT_ANDROID_REL section is broken.
 
 # RUN: yaml2obj --docnum=2 -DLINK=0xffffffff %s -o %t2.broken.link
 # RUN: llvm-readobj --relocations %t2.broken.link 2>&1 | \
 # RUN:   FileCheck -DFILE=%t2.broken.link --check-prefix=BROKEN-REL-LINK-LLVM %s
 # RUN: llvm-readelf --relocations %t2.broken.link 2>&1 | \
 # RUN:   FileCheck -DFILE=%t2.broken.link --check-prefix=BROKEN-REL-LINK-GNU %s

llvm/test/tools/llvm-readobj/ELF/relr-relocs.test

 
 ## Check we report a warning when we are unable to dump relocations
 ## for a SHT_RELR/SHT_ANDROID_RELR section.
 
 ## Case A: check the case when relocations can't be read from an SHT_RELR section.
 # RUN: yaml2obj --docnum=2 -DENTSIZE=1 %s -o %t2.broken
 # RUN: llvm-readobj --relocations %t2.broken 2>&1 | \
 # RUN:   FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-LLVM %s -DSECNAME=SHT_RELR
-# RUN: not llvm-readelf --relocations %t2.broken 2>&1 | \
-# RUN:   FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-GNU %s
+# RUN: llvm-readelf --relocations %t2.broken 2>&1 | \
+# RUN:   FileCheck -DFILE=%t2.broken --check-prefix=BROKEN-GNU %s -DSECNAME=SHT_RELR
 
 # BROKEN-LLVM:      Relocations [
 # BROKEN-LLVM-NEXT:   Section (1) .relr.dyn {
 # BROKEN-LLVM-NEXT: warning: '[[FILE]]': unable to read relocations from [[SECNAME]] section with index 1: section [index 1] has an invalid sh_entsize: 1
 # BROKEN-LLVM-NEXT:   }
 # BROKEN-LLVM-NEXT: ]
 
-## FIXME: GNU still reports an error before trying to dump relocations.
-# BROKEN-GNU: error: '[[FILE]]': section [index 1] has an invalid sh_entsize: 1
+# BROKEN-GNU:      warning: '[[FILE]]': unable to get the number of relocations in [[SECNAME]] section with index 1: section [index 1] has an invalid sh_entsize: 1
+# BROKEN-GNU:      Relocation section '.relr.dyn' at offset 0x34 contains <?> entries:
+# BROKEN-GNU-NEXT:  Offset     Info    Type                Sym. Value  Symbol's Name
+# BROKEN-GNU-NEXT: warning: '[[FILE]]': unable to read relocations from [[SECNAME]] section with index 1: section [index 1] has an invalid sh_entsize: 1
 
 ## Case B: check the case when relocations can't be read from an SHT_ANDROID_RELR section.
 ##         SHT_ANDROID_RELR = 0x6fffff00.
 # RUN: yaml2obj --docnum=2 -DENTSIZE=1 -DSHTYPE=0x6fffff00 %s -o %t2.broken.android
 # RUN: llvm-readobj --relocations %t2.broken.android 2>&1 | \
 # RUN:   FileCheck -DFILE=%t2.broken.android --check-prefix=BROKEN-LLVM %s -DSECNAME=SHT_ANDROID_RELR
-
-# RUN: not llvm-readelf --relocations %t2.broken.android 2>&1 | \
-# RUN:   FileCheck -DFILE=%t2.broken.android --check-prefix=BROKEN-GNU %s
+# RUN: llvm-readelf --relocations %t2.broken.android 2>&1 | \
+# RUN:   FileCheck -DFILE=%t2.broken.android --check-prefix=BROKEN-GNU %s -DSECNAME=SHT_ANDROID_RELR
 
 ## Check the behavior when the sh_link field of the SHT_RELR/SHT_ANDROID_RELR section
 ## is set to an arbitrary value. Normally, it is set to 0, because such sections contains
 ## only relative relocations and do not have an associated symbol table, like other
 ## relocation sections.
 
 ## Case A: check we do not report warnings when the sh_link field is set to an arbitrary value
 ##         and the --relocations option is requested.

llvm/tools/llvm-readobj/ELFDumper.cpp

 static bool isRelocationSec(const typename ELFT::Shdr &Sec) {
   return Sec.sh_type == ELF::SHT_REL || Sec.sh_type == ELF::SHT_RELA ||
          Sec.sh_type == ELF::SHT_RELR || Sec.sh_type == ELF::SHT_ANDROID_REL ||
          Sec.sh_type == ELF::SHT_ANDROID_RELA ||
          Sec.sh_type == ELF::SHT_ANDROID_RELR;
 }
 
 template <class ELFT> void GNUStyle<ELFT>::printRelocations(const ELFO *Obj) {
-  bool HasRelocSections = false;
-  for (const Elf_Shdr &Sec : cantFail(Obj->sections())) {
-    if (!isRelocationSec<ELFT>(Sec))
-      continue;
-    HasRelocSections = true;
-
-    unsigned Entries;
+  auto GetEntriesNum = [&](const Elf_Shdr &Sec) -> Expected<size_t> {
     // Android's packed relocation section needs to be unpacked first
     // to get the actual number of entries.
     if (Sec.sh_type == ELF::SHT_ANDROID_REL ||
         Sec.sh_type == ELF::SHT_ANDROID_RELA) {
-      Entries = unwrapOrError(this->FileName, Obj->android_relas(&Sec)).size();
-    } else if (!opts::RawRelr && (Sec.sh_type == ELF::SHT_RELR ||
-                                  Sec.sh_type == ELF::SHT_ANDROID_RELR)) {
-      Elf_Relr_Range Relrs = unwrapOrError(this->FileName, Obj->relrs(&Sec));
-      Entries = Obj->decode_relrs(Relrs).size();
-    } else {
-      Entries = Sec.getEntityCount();
+      Expected<std::vector<typename ELFT::Rela>> RelasOrErr =
+          Obj->android_relas(&Sec);
+      if (!RelasOrErr)
+        return RelasOrErr.takeError();
+      return RelasOrErr->size();
+    }
+
+    if (!opts::RawRelr && (Sec.sh_type == ELF::SHT_RELR ||
+      Expected<Elf_Relr_Range> RelrsOrErr = Obj->relrs(&Sec);
+      if (!RelrsOrErr)
+        return RelrsOrErr.takeError();
+      return Obj->decode_relrs(*RelrsOrErr).size();
     }
 
+    return Sec.getEntityCount();
+  };
+
+  bool HasRelocSections = false;
+  for (const Elf_Shdr &Sec : cantFail(Obj->sections())) {
+    if (!isRelocationSec<ELFT>(Sec))
+      continue;
+    HasRelocSections = true;
+
+    std::string EntriesNum = "<?>";
+    if (Expected<size_t> NumOrErr = GetEntriesNum(Sec))
+      EntriesNum = std::to_string(*NumOrErr);
+    else
+      this->reportUniqueWarning(createError(
+          "unable to get the number of relocations in " + describe(Obj, Sec) +
+          ": " + toString(NumOrErr.takeError())));
+
     uintX_t Offset = Sec.sh_offset;
     StringRef Name = this->getPrintableSectionName(Obj, Sec);
     OS << "\nRelocation section '" << Name << "' at offset 0x"
-       << to_hexString(Offset, false) << " contains " << Entries
+       << to_hexString(Offset, false) << " contains " << EntriesNum
        << " entries:\n";
     printRelocHeader(Sec.sh_type);
     this->printRelocationsHelper(Obj, Sec);
   }
   if (!HasRelocSections)
     OS << "\nThere are no relocations in this file.\n";
 }