[llvm-objdump] - Move getRelocationValueString and dependenices out of the llvm-objdump.cpp

[grimar]

Summary

getRelocationValueString is a dispatcher function that calls the
corresponding ELF/COFF/Wasm/MachO implementations
that currently live in the llvm-objdump.cpp file.

I think these implementations should be moved to ELFDump.cpp,
COFFDump.cpp and other corresponding files, to move platform specific
implementation out from the common logic.

The patch does that. Also, I had to move ToolSectionFilter helper and SectionFilterIterator,
SectionFilter to a header to make them available across the objdump code.
That was needed for COFF, other implementations do not use ToolSectionFilter.
But it should be OK.

It depends on D56721 that was LGTMed but not yet landed.

[grimar]

This patch only moves the code and renames the few methods. No other changes were performed.

[jhenderson]

It depends on D56721 that was LGTMed but not yet landed.

FYI, I'm just verifying the latest version of this, following the last batch of updates, and I'll commit it after it's passed the test.

LGTM. I agree with your reasoning for moving them.

tools/llvm-objdump/llvm-objdump.h

74

This is probably fine as is, but I wonder if it actually belongs in the Object library?

[grimar]

tools/llvm-objdump/llvm-objdump.h

74

I would be happy to not have it here. But I think we need to find more users for this to move it out first? Until it is proved to be useful outside of llvm-objdump, I would keep it here.

[sbc100]

tools/llvm-objdump/WasmDump.cpp

53

Missing newline at EOF

tools/llvm-objdump/llvm-objdump.h

139

Why not continue to use overloads?

[grimar]

tools/llvm-objdump/llvm-objdump.h

139

There are few benefits from not using them here, and I see no profit.

Now we have a code that looks like:

static std::error_code getRelocationValueString(const ELFObjectFileBase *Obj,
                                                const RelocationRef &Rel,
                                                SmallVectorImpl<char> &Result) {
  if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
    return getRelocationValueString(ELF32LE, Rel, Result);
  if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
    return getRelocationValueString(ELF64LE, Rel, Result);
  if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
    return getRelocationValueString(ELF32BE, Rel, Result);
  auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
  return getRelocationValueString(ELF64BE, Rel, Result);
}

static std::error_code getRelocationValueString(const RelocationRef &Rel,
                                                SmallVectorImpl<char> &Result) {
  const ObjectFile *Obj = Rel.getObject();
  if (auto *ELF = dyn_cast<ELFObjectFileBase>(Obj))
    return getRelocationValueString(ELF, Rel, Result);
  if (auto *COFF = dyn_cast<COFFObjectFile>(Obj))
    return getRelocationValueString(COFF, Rel, Result);
  if (auto *Wasm = dyn_cast<WasmObjectFile>(Obj))
    return getRelocationValueString(Wasm, Rel, Result);
  if (auto *MachO = dyn_cast<MachOObjectFile>(Obj))
    return getRelocationValueString(MachO, Rel, Result);
  llvm_unreachable("unknown object file format");
}

It seems to be completely unreadable. Looking at this code I can hardly realize that dispatcher function getRelocationValueString
will call ELF version of getRelocationValueString which will call one more getRelocationValueString basing on ELFT.
It is painful to trace.

The second benefit is that other methods in this header contain the COFF/ELF/Wasm/MachO prefixes/suffixes.
I think we might want to regroup them by the target, having them mixed does not look good.
So renaming will be important for consistency.

These implementations have no much common inside, after all, to name them in the same way. Logically this is a 4 really different implementations.

tools/llvm-objdump/COFFDump.cpp

for (const SectionRef &Section : Obj->sections()) {
 
     RFStart = reinterpret_cast<const RuntimeFunction *>(Contents.data());
     NumRFs = Contents.size() / sizeof(RuntimeFunction);
     return true;
   }
   return false;
 }
 
+std::error_code
+llvm::getCOFFRelocationValueString(const COFFObjectFile *Obj,
+                                   const RelocationRef &Rel,
+                                   SmallVectorImpl<char> &Result) {
+  symbol_iterator SymI = Rel.getSymbol();
+  Expected<StringRef> SymNameOrErr = SymI->getName();
+  if (!SymNameOrErr)
+    return errorToErrorCode(SymNameOrErr.takeError());
+  StringRef SymName = *SymNameOrErr;
+  Result.append(SymName.begin(), SymName.end());
+  return std::error_code();
+}
+
 static void printWin64EHUnwindInfo(const Win64EH::UnwindInfo *UI) {
   // The casts to int are required in order to output the value as number.
   // Without the casts the value would be interpreted as char data (which
   // results in garbage output).
   outs() << "    Version: " << static_cast<int>(UI->getVersion()) << "\n";
   outs() << "    Flags: " << static_cast<int>(UI->getFlags());
   if (UI->getFlags()) {
     if (UI->getFlags() & UNW_ExceptionHandler)

tools/llvm-objdump/ELFDump.cpp

for (const typename ELFO::Elf_Shdr &Sec : *SectionsOrError) {
     if (Sec.sh_type == ELF::SHT_DYNSYM)
       return Elf->getStringTableForSymtab(Sec);
   }
 
   return createError("dynamic string table not found");
 }
 
 template <class ELFT>
+static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
+                                                const RelocationRef &RelRef,
+                                                SmallVectorImpl<char> &Result) {
+  typedef typename ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
+  typedef typename ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
+  typedef typename ELFObjectFile<ELFT>::Elf_Rela Elf_Rela;
+
+  const ELFFile<ELFT> &EF = *Obj->getELFFile();
+  DataRefImpl Rel = RelRef.getRawDataRefImpl();
+  auto SecOrErr = EF.getSection(Rel.d.a);
+  if (!SecOrErr)
+    return errorToErrorCode(SecOrErr.takeError());
+
+  int64_t Addend = 0;
+  // If there is no Symbol associated with the relocation, we set the undef
+  // boolean value to 'true'. This will prevent us from calling functions that
+  // requires the relocation to be associated with a symbol.
+  //
+  // In SHT_REL case we would need to read the addend from section data.
+  // GNU objdump does not do that and we just follow for simplicity atm.
+  bool Undef = false;
+  if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
+    const Elf_Rela *ERela = Obj->getRela(Rel);
+    Addend = ERela->r_addend;
+    Undef = ERela->getSymbol(false) == 0;
+  } else if ((*SecOrErr)->sh_type != ELF::SHT_REL) {
+    return object_error::parse_failed;
+  }
+
+  // Default scheme is to print Target, as well as "+ <addend>" for nonzero
+  // addend. Should be acceptable for all normal purposes.
+  std::string FmtBuf;
+  raw_string_ostream Fmt(FmtBuf);
+
+  if (!Undef) {
+    symbol_iterator SI = RelRef.getSymbol();
+    const Elf_Sym *Sym = Obj->getSymbol(SI->getRawDataRefImpl());
+    if (Sym->getType() == ELF::STT_SECTION) {
+      Expected<section_iterator> SymSI = SI->getSection();
+      if (!SymSI)
+        return errorToErrorCode(SymSI.takeError());
+      const Elf_Shdr *SymSec = Obj->getSection((*SymSI)->getRawDataRefImpl());
+      auto SecName = EF.getSectionName(SymSec);
+      if (!SecName)
+        return errorToErrorCode(SecName.takeError());
+      Fmt << *SecName;
+    } else {
+      Expected<StringRef> SymName = SI->getName();
+      if (!SymName)
+        return errorToErrorCode(SymName.takeError());
+      if (Demangle)
+        Fmt << demangle(*SymName);
+      else
+        Fmt << *SymName;
+    }
+  } else {
+    Fmt << "*ABS*";
+  }
+
+  if (Addend != 0)
+    Fmt << (Addend < 0 ? "" : "+") << Addend;
+  Fmt.flush();
+  Result.append(FmtBuf.begin(), FmtBuf.end());
+  return std::error_code();
+}
+
+std::error_code
+llvm::getELFRelocationValueString(const ELFObjectFileBase *Obj,
+                                  const RelocationRef &Rel,
+                                  SmallVectorImpl<char> &Result) {
+  if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
+    return getRelocationValueString(ELF32LE, Rel, Result);
+  if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
+    return getRelocationValueString(ELF64LE, Rel, Result);
+  if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
+    return getRelocationValueString(ELF32BE, Rel, Result);
+  auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
+  return getRelocationValueString(ELF64BE, Rel, Result);
+}
+
+template <class ELFT>
 void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
   auto ProgramHeaderOrError = Elf->program_headers();
   if (!ProgramHeaderOrError)
     report_error(Filename, ProgramHeaderOrError.takeError());
 
   auto DynamicEntriesOrError = Elf->dynamicEntries();
   if (!DynamicEntriesOrError)
     report_error(Filename, DynamicEntriesOrError.takeError());

tools/llvm-objdump/MachODump.cpp

if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) {
       if (!BaseSegmentAddressSet && SegName != "__PAGEZERO") {
         BaseSegmentAddressSet = true;
         BaseSegmentAddress = SLC.vmaddr;
       }
     }
   }
 }
 
+static void printRelocationTargetName(const MachOObjectFile *O,
+                                      const MachO::any_relocation_info &RE,
+                                      raw_string_ostream &Fmt) {
+  // Target of a scattered relocation is an address.  In the interest of
+  // generating pretty output, scan through the symbol table looking for a
+  // symbol that aligns with that address.  If we find one, print it.
+  // Otherwise, we just print the hex address of the target.
+  if (O->isRelocationScattered(RE)) {
+    uint32_t Val = O->getPlainRelocationSymbolNum(RE);
+
+    for (const SymbolRef &Symbol : O->symbols()) {
+      Expected<uint64_t> Addr = Symbol.getAddress();
+      if (!Addr)
+        report_error(O->getFileName(), Addr.takeError());
+      if (*Addr != Val)
+        continue;
+      Expected<StringRef> Name = Symbol.getName();
+      if (!Name)
+        report_error(O->getFileName(), Name.takeError());
+      Fmt << *Name;
+      return;
+    }
+
+    // If we couldn't find a symbol that this relocation refers to, try
+    // to find a section beginning instead.
+    for (const SectionRef &Section : ToolSectionFilter(*O)) {
+      std::error_code ec;
+
+      StringRef Name;
+      uint64_t Addr = Section.getAddress();
+      if (Addr != Val)
+        continue;
+      if ((ec = Section.getName(Name)))
+        report_error(O->getFileName(), ec);
+      Fmt << Name;
+      return;
+    }
+
+    Fmt << format("0x%x", Val);
+    return;
+  }
+
+  StringRef S;
+  bool isExtern = O->getPlainRelocationExternal(RE);
+  uint64_t Val = O->getPlainRelocationSymbolNum(RE);
+
+  if (O->getAnyRelocationType(RE) == MachO::ARM64_RELOC_ADDEND) {
+    Fmt << format("0x%0" PRIx64, Val);
+    return;
+  }
+
+  if (isExtern) {
+    symbol_iterator SI = O->symbol_begin();
+    advance(SI, Val);
+    Expected<StringRef> SOrErr = SI->getName();
+    if (!SOrErr)
+      report_error(O->getFileName(), SOrErr.takeError());
+    S = *SOrErr;
+  } else {
+    section_iterator SI = O->section_begin();
+    // Adjust for the fact that sections are 1-indexed.
+    if (Val == 0) {
+      Fmt << "0 (?,?)";
+      return;
+    }
+    uint32_t I = Val - 1;
+    while (I != 0 && SI != O->section_end()) {
+      --I;
+      advance(SI, 1);
+    }
+    if (SI == O->section_end())
+      Fmt << Val << " (?,?)";
+    else
+      SI->getName(S);
+  }
+
+  Fmt << S;
+}
+
+std::error_code
+llvm::getMachORelocationValueString(const MachOObjectFile *Obj,
+                                    const RelocationRef &RelRef,
+                                    SmallVectorImpl<char> &Result) {
+  DataRefImpl Rel = RelRef.getRawDataRefImpl();
+  MachO::any_relocation_info RE = Obj->getRelocation(Rel);
+
+  unsigned Arch = Obj->getArch();
+
+  std::string FmtBuf;
+  raw_string_ostream Fmt(FmtBuf);
+  unsigned Type = Obj->getAnyRelocationType(RE);
+  bool IsPCRel = Obj->getAnyRelocationPCRel(RE);
+
+  // Determine any addends that should be displayed with the relocation.
+  // These require decoding the relocation type, which is triple-specific.
+
+  // X86_64 has entirely custom relocation types.
+  if (Arch == Triple::x86_64) {
+    switch (Type) {
+    case MachO::X86_64_RELOC_GOT_LOAD:
+    case MachO::X86_64_RELOC_GOT: {
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "@GOT";
+      if (IsPCRel)
+        Fmt << "PCREL";
+      break;
+    }
+    case MachO::X86_64_RELOC_SUBTRACTOR: {
+      DataRefImpl RelNext = Rel;
+      Obj->moveRelocationNext(RelNext);
+      MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
+
+      // X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
+      // X86_64_RELOC_UNSIGNED.
+      // NOTE: Scattered relocations don't exist on x86_64.
+      unsigned RType = Obj->getAnyRelocationType(RENext);
+      if (RType != MachO::X86_64_RELOC_UNSIGNED)
+        report_error(Obj->getFileName(), "Expected X86_64_RELOC_UNSIGNED after "
+                                         "X86_64_RELOC_SUBTRACTOR.");
+
+      // The X86_64_RELOC_UNSIGNED contains the minuend symbol;
+      // X86_64_RELOC_SUBTRACTOR contains the subtrahend.
+      printRelocationTargetName(Obj, RENext, Fmt);
+      Fmt << "-";
+      printRelocationTargetName(Obj, RE, Fmt);
+      break;
+    }
+    case MachO::X86_64_RELOC_TLV:
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "@TLV";
+      if (IsPCRel)
+        Fmt << "P";
+      break;
+    case MachO::X86_64_RELOC_SIGNED_1:
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "-1";
+      break;
+    case MachO::X86_64_RELOC_SIGNED_2:
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "-2";
+      break;
+    case MachO::X86_64_RELOC_SIGNED_4:
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "-4";
+      break;
+    default:
+      printRelocationTargetName(Obj, RE, Fmt);
+      break;
+    }
+    // X86 and ARM share some relocation types in common.
+  } else if (Arch == Triple::x86 || Arch == Triple::arm ||
+             Arch == Triple::ppc) {
+    // Generic relocation types...
+    switch (Type) {
+    case MachO::GENERIC_RELOC_PAIR: // prints no info
+      return std::error_code();
+    case MachO::GENERIC_RELOC_SECTDIFF: {
+      DataRefImpl RelNext = Rel;
+      Obj->moveRelocationNext(RelNext);
+      MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
+
+      // X86 sect diff's must be followed by a relocation of type
+      // GENERIC_RELOC_PAIR.
+      unsigned RType = Obj->getAnyRelocationType(RENext);
+
+      if (RType != MachO::GENERIC_RELOC_PAIR)
+        report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
+                                         "GENERIC_RELOC_SECTDIFF.");
+
+      printRelocationTargetName(Obj, RE, Fmt);
+      Fmt << "-";
+      printRelocationTargetName(Obj, RENext, Fmt);
+      break;
+    }
+    }
+
+    if (Arch == Triple::x86 || Arch == Triple::ppc) {
+      switch (Type) {
+      case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
+        DataRefImpl RelNext = Rel;
+        Obj->moveRelocationNext(RelNext);
+        MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
+
+        // X86 sect diff's must be followed by a relocation of type
+        // GENERIC_RELOC_PAIR.
+        unsigned RType = Obj->getAnyRelocationType(RENext);
+        if (RType != MachO::GENERIC_RELOC_PAIR)
+          report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
+                                           "GENERIC_RELOC_LOCAL_SECTDIFF.");
+
+        printRelocationTargetName(Obj, RE, Fmt);
+        Fmt << "-";
+        printRelocationTargetName(Obj, RENext, Fmt);
+        break;
+      }
+      case MachO::GENERIC_RELOC_TLV: {
+        printRelocationTargetName(Obj, RE, Fmt);
+        Fmt << "@TLV";
+        if (IsPCRel)
+          Fmt << "P";
+        break;
+      }
+      default:
+        printRelocationTargetName(Obj, RE, Fmt);
+      }
+    } else { // ARM-specific relocations
+      switch (Type) {
+      case MachO::ARM_RELOC_HALF:
+      case MachO::ARM_RELOC_HALF_SECTDIFF: {
+        // Half relocations steal a bit from the length field to encode
+        // whether this is an upper16 or a lower16 relocation.
+        bool isUpper = (Obj->getAnyRelocationLength(RE) & 0x1) == 1;
+
+        if (isUpper)
+          Fmt << ":upper16:(";
+        else
+          Fmt << ":lower16:(";
+        printRelocationTargetName(Obj, RE, Fmt);
+
+        DataRefImpl RelNext = Rel;
+        Obj->moveRelocationNext(RelNext);
+        MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
+
+        // ARM half relocs must be followed by a relocation of type
+        // ARM_RELOC_PAIR.
+        unsigned RType = Obj->getAnyRelocationType(RENext);
+        if (RType != MachO::ARM_RELOC_PAIR)
+          report_error(Obj->getFileName(), "Expected ARM_RELOC_PAIR after "
+                                           "ARM_RELOC_HALF");
+
+        // NOTE: The half of the target virtual address is stashed in the
+        // address field of the secondary relocation, but we can't reverse
+        // engineer the constant offset from it without decoding the movw/movt
+        // instruction to find the other half in its immediate field.
+
+        // ARM_RELOC_HALF_SECTDIFF encodes the second section in the
+        // symbol/section pointer of the follow-on relocation.
+        if (Type == MachO::ARM_RELOC_HALF_SECTDIFF) {
+          Fmt << "-";
+          printRelocationTargetName(Obj, RENext, Fmt);
+        }
+
+        Fmt << ")";
+        break;
+      }
+      default: {
+        printRelocationTargetName(Obj, RE, Fmt);
+      }
+      }
+    }
+  } else
+    printRelocationTargetName(Obj, RE, Fmt);
+
+  Fmt.flush();
+  Result.append(FmtBuf.begin(), FmtBuf.end());
+  return std::error_code();
+}
+
 static void PrintIndirectSymbolTable(MachOObjectFile *O, bool verbose,
                                      uint32_t n, uint32_t count,
                                      uint32_t stride, uint64_t addr) {
   MachO::dysymtab_command Dysymtab = O->getDysymtabLoadCommand();
   uint32_t nindirectsyms = Dysymtab.nindirectsyms;
   if (n > nindirectsyms)
     outs() << " (entries start past the end of the indirect symbol "
               "table) (reserved1 field greater than the table size)";

tools/llvm-objdump/WasmDump.cpp

 void llvm::printWasmFileHeader(const object::ObjectFile *Obj) {
   const WasmObjectFile *File = dyn_cast<const WasmObjectFile>(Obj);
 
   outs() << "Program Header:\n";
   outs() << "Version: 0x";
   outs().write_hex(File->getHeader().Version);
   outs() << "\n";
 }
+
+std::error_code
+llvm::getWasmRelocationValueString(const WasmObjectFile *Obj,
+                                   const RelocationRef &RelRef,
+                                   SmallVectorImpl<char> &Result) {
+  const wasm::WasmRelocation &Rel = Obj->getWasmRelocation(RelRef);
+  symbol_iterator SI = RelRef.getSymbol();
+  std::string FmtBuf;
+  raw_string_ostream Fmt(FmtBuf);
+  if (SI == Obj->symbol_end()) {
+    // Not all wasm relocations have symbols associated with them.
+    // In particular R_WEBASSEMBLY_TYPE_INDEX_LEB.
+    Fmt << Rel.Index;
+  } else {
+    Expected<StringRef> SymNameOrErr = SI->getName();
+    if (!SymNameOrErr)
+      return errorToErrorCode(SymNameOrErr.takeError());
+    StringRef SymName = *SymNameOrErr;
+    Result.append(SymName.begin(), SymName.end());
+  }
+  Fmt << (Rel.Addend < 0 ? "" : "+") << Rel.Addend;
+  Fmt.flush();
+  Result.append(FmtBuf.begin(), FmtBuf.end());
+  return std::error_code();
+}
 No newline at end of file

tools/llvm-objdump/llvm-objdump.h

 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Object/Archive.h"
 
 namespace llvm {
 class StringRef;
 
 namespace object {
-  class COFFObjectFile;
-  class COFFImportFile;
-  class MachOObjectFile;
-  class MachOUniversalBinary;
-  class ObjectFile;
-  class Archive;
-  class RelocationRef;
+class ELFObjectFileBase;
 }
 
 extern cl::opt<std::string> TripleName;
 extern cl::opt<std::string> ArchName;
 extern cl::opt<std::string> MCPU;
 extern cl::list<std::string> MAttrs;
 extern cl::list<std::string> FilterSections;
 extern cl::opt<bool> AllHeaders;

 extern cl::opt<bool> DynamicRelocations;
 extern cl::opt<bool> SectionHeaders;
 extern cl::opt<bool> SectionContents;
 extern cl::opt<bool> SymbolTable;
 extern cl::opt<bool> UnwindInfo;
 extern cl::opt<bool> PrintImmHex;
 extern cl::opt<DIDumpType> DwarfDumpType;
 
+typedef std::function<bool(llvm::object::SectionRef const &)> FilterPredicate;
+
+class SectionFilterIterator {
+public:
+  SectionFilterIterator(FilterPredicate P,
+                        llvm::object::section_iterator const &I,
+                        llvm::object::section_iterator const &E)
+      : Predicate(std::move(P)), Iterator(I), End(E) {
+    ScanPredicate();
+  }
+  const llvm::object::SectionRef &operator*() const { return *Iterator; }
+  SectionFilterIterator &operator++() {
+    ++Iterator;
+    ScanPredicate();
+    return *this;
+  }
+  bool operator!=(SectionFilterIterator const &Other) const {
+    return Iterator != Other.Iterator;
+  }
+
+private:
+  void ScanPredicate() {
+    while (Iterator != End && !Predicate(*Iterator)) {
+      ++Iterator;
+    }
+  }
+  FilterPredicate Predicate;
+  llvm::object::section_iterator Iterator;
+  llvm::object::section_iterator End;
+};
+
+class SectionFilter {
+public:
+  SectionFilter(FilterPredicate P, llvm::object::ObjectFile const &O)
+      : Predicate(std::move(P)), Object(O) {}
+  SectionFilterIterator begin() {
+    return SectionFilterIterator(Predicate, Object.section_begin(),
+                                 Object.section_end());
+  }
+  SectionFilterIterator end() {
+    return SectionFilterIterator(Predicate, Object.section_end(),
+                                 Object.section_end());
+  }
+
+private:
+  FilterPredicate Predicate;
+  llvm::object::ObjectFile const &Object;
+};
+
 // Various helper functions.
+SectionFilter ToolSectionFilter(llvm::object::ObjectFile const &O);
+
+std::error_code
+getELFRelocationValueString(const object::ELFObjectFileBase *Obj,
+                            const object::RelocationRef &Rel,
+                            llvm::SmallVectorImpl<char> &Result);
+std::error_code
+getCOFFRelocationValueString(const object::COFFObjectFile *Obj,
+                             const object::RelocationRef &Rel,
+                             llvm::SmallVectorImpl<char> &Result);
+std::error_code
+getWasmRelocationValueString(const object::WasmObjectFile *Obj,
+                             const object::RelocationRef &RelRef,
+                             llvm::SmallVectorImpl<char> &Result);
+std::error_code
+getMachORelocationValueString(const object::MachOObjectFile *Obj,
+                              const object::RelocationRef &RelRef,
+                              llvm::SmallVectorImpl<char> &Result);
+
 void error(std::error_code ec);
 bool isRelocAddressLess(object::RelocationRef A, object::RelocationRef B);
 void parseInputMachO(StringRef Filename);
 void parseInputMachO(object::MachOUniversalBinary *UB);
 void printCOFFUnwindInfo(const object::COFFObjectFile *O);
 void printMachOUnwindInfo(const object::MachOObjectFile *O);
 void printMachOExportsTrie(const object::MachOObjectFile *O);
 void printMachORebaseTable(object::MachOObjectFile *O);

tools/llvm-objdump/llvm-objdump.cpp

 cl::alias DisassembleZeroesShort("z",
                                  cl::desc("Alias for --disassemble-zeroes"),
                                  cl::aliasopt(DisassembleZeroes));
 
 static StringRef ToolName;
 
 typedef std::vector<std::tuple<uint64_t, StringRef, uint8_t>> SectionSymbolsTy;
 
-namespace {
-typedef std::function<bool(llvm::object::SectionRef const &)> FilterPredicate;
-
-class SectionFilterIterator {
-public:
-  SectionFilterIterator(FilterPredicate P,
-                        llvm::object::section_iterator const &I,
-                        llvm::object::section_iterator const &E)
-      : Predicate(std::move(P)), Iterator(I), End(E) {
-    ScanPredicate();
-  }
-  const llvm::object::SectionRef &operator*() const { return *Iterator; }
-  SectionFilterIterator &operator++() {
-    ++Iterator;
-    ScanPredicate();
-    return *this;
-  }
-  bool operator!=(SectionFilterIterator const &Other) const {
-    return Iterator != Other.Iterator;
-  }
-
-private:
-  void ScanPredicate() {
-    while (Iterator != End && !Predicate(*Iterator)) {
-      ++Iterator;
-    }
-  }
-  FilterPredicate Predicate;
-  llvm::object::section_iterator Iterator;
-  llvm::object::section_iterator End;
-};
-
-class SectionFilter {
-public:
-  SectionFilter(FilterPredicate P, llvm::object::ObjectFile const &O)
-      : Predicate(std::move(P)), Object(O) {}
-  SectionFilterIterator begin() {
-    return SectionFilterIterator(Predicate, Object.section_begin(),
-                                 Object.section_end());
-  }
-  SectionFilterIterator end() {
-    return SectionFilterIterator(Predicate, Object.section_end(),
-                                 Object.section_end());
-  }
-
-private:
-  FilterPredicate Predicate;
-  llvm::object::ObjectFile const &Object;
-};
-SectionFilter ToolSectionFilter(llvm::object::ObjectFile const &O) {
+SectionFilter llvm::ToolSectionFilter(llvm::object::ObjectFile const &O) {
   return SectionFilter(
       [](llvm::object::SectionRef const &S) {
         if (FilterSections.empty())
           return true;
         llvm::StringRef String;
         std::error_code error = S.getName(String);
         if (error)
           return false;
         return is_contained(FilterSections, String);
       },
       O);
 }
-}
 
 void llvm::error(std::error_code EC) {
   if (!EC)
     return;
   WithColor::error(errs(), ToolName)
       << "reading file: " << EC.message() << ".\n";
   errs().flush();
   exit(1);
static std::string demangle(StringRef Name) {
   if (!Demangled)
     return Name;
 
   std::string Ret = Demangled;
   free(Demangled);
   return Ret;
 }
 
-template <class ELFT>
-static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
-                                                const RelocationRef &RelRef,
-                                                SmallVectorImpl<char> &Result) {
-  typedef typename ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
-  typedef typename ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
-  typedef typename ELFObjectFile<ELFT>::Elf_Rela Elf_Rela;
-
-  const ELFFile<ELFT> &EF = *Obj->getELFFile();
-  DataRefImpl Rel = RelRef.getRawDataRefImpl();
-  auto SecOrErr = EF.getSection(Rel.d.a);
-  if (!SecOrErr)
-    return errorToErrorCode(SecOrErr.takeError());
-
-  int64_t Addend = 0;
-  // If there is no Symbol associated with the relocation, we set the undef
-  // boolean value to 'true'. This will prevent us from calling functions that
-  // requires the relocation to be associated with a symbol.
-  //
-  // In SHT_REL case we would need to read the addend from section data.
-  // GNU objdump does not do that and we just follow for simplicity.
-  bool Undef = false;
-  if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
-    const Elf_Rela *ERela = Obj->getRela(Rel);
-    Addend = ERela->r_addend;
-    Undef = ERela->getSymbol(false) == 0;
-  } else if ((*SecOrErr)->sh_type != ELF::SHT_REL) {
-    return object_error::parse_failed;
-  }
-
-  // Default scheme is to print Target, as well as "+ <addend>" for nonzero
-  // addend. Should be acceptable for all normal purposes.
-  std::string FmtBuf;
-  raw_string_ostream Fmt(FmtBuf);
-
-  if (!Undef) {
-    symbol_iterator SI = RelRef.getSymbol();
-    const Elf_Sym *Sym = Obj->getSymbol(SI->getRawDataRefImpl());
-    if (Sym->getType() == ELF::STT_SECTION) {
-      Expected<section_iterator> SymSI = SI->getSection();
-      if (!SymSI)
-        return errorToErrorCode(SymSI.takeError());
-      const Elf_Shdr *SymSec = Obj->getSection((*SymSI)->getRawDataRefImpl());
-      auto SecName = EF.getSectionName(SymSec);
-      if (!SecName)
-        return errorToErrorCode(SecName.takeError());
-      Fmt << *SecName;
-    } else {
-      Expected<StringRef> SymName = SI->getName();
-      if (!SymName)
-        return errorToErrorCode(SymName.takeError());
-      if (Demangle)
-        Fmt << demangle(*SymName);
-      else
-        Fmt << *SymName;
-    }
-  } else {
-    Fmt << "*ABS*";
-  }
-
-  if (Addend != 0)
-    Fmt << (Addend < 0 ? "" : "+") << Addend;
-  Fmt.flush();
-  Result.append(FmtBuf.begin(), FmtBuf.end());
-  return std::error_code();
-}
-
-static std::error_code getRelocationValueString(const ELFObjectFileBase *Obj,
-                                                const RelocationRef &Rel,
-                                                SmallVectorImpl<char> &Result) {
-  if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
-    return getRelocationValueString(ELF32LE, Rel, Result);
-  if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
-    return getRelocationValueString(ELF64LE, Rel, Result);
-  if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
-    return getRelocationValueString(ELF32BE, Rel, Result);
-  auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
-  return getRelocationValueString(ELF64BE, Rel, Result);
-}
-
-static std::error_code getRelocationValueString(const COFFObjectFile *Obj,
-                                                const RelocationRef &Rel,
-                                                SmallVectorImpl<char> &Result) {
-  symbol_iterator SymI = Rel.getSymbol();
-  Expected<StringRef> SymNameOrErr = SymI->getName();
-  if (!SymNameOrErr)
-    return errorToErrorCode(SymNameOrErr.takeError());
-  StringRef SymName = *SymNameOrErr;
-  Result.append(SymName.begin(), SymName.end());
-  return std::error_code();
-}
-
-static void printRelocationTargetName(const MachOObjectFile *O,
-                                      const MachO::any_relocation_info &RE,
-                                      raw_string_ostream &Fmt) {
-  // Target of a scattered relocation is an address.  In the interest of
-  // generating pretty output, scan through the symbol table looking for a
-  // symbol that aligns with that address.  If we find one, print it.
-  // Otherwise, we just print the hex address of the target.
-  if (O->isRelocationScattered(RE)) {
-    uint32_t Val = O->getPlainRelocationSymbolNum(RE);
-
-    for (const SymbolRef &Symbol : O->symbols()) {
-      Expected<uint64_t> Addr = Symbol.getAddress();
-      if (!Addr)
-        report_error(O->getFileName(), Addr.takeError());
-      if (*Addr != Val)
-        continue;
-      Expected<StringRef> Name = Symbol.getName();
-      if (!Name)
-        report_error(O->getFileName(), Name.takeError());
-      Fmt << *Name;
-      return;
-    }
-
-    // If we couldn't find a symbol that this relocation refers to, try
-    // to find a section beginning instead.
-    for (const SectionRef &Section : ToolSectionFilter(*O)) {
-      std::error_code ec;
-
-      StringRef Name;
-      uint64_t Addr = Section.getAddress();
-      if (Addr != Val)
-        continue;
-      if ((ec = Section.getName(Name)))
-        report_error(O->getFileName(), ec);
-      Fmt << Name;
-      return;
-    }
-
-    Fmt << format("0x%x", Val);
-    return;
-  }
-
-  StringRef S;
-  bool isExtern = O->getPlainRelocationExternal(RE);
-  uint64_t Val = O->getPlainRelocationSymbolNum(RE);
-
-  if (O->getAnyRelocationType(RE) == MachO::ARM64_RELOC_ADDEND) {
-    Fmt << format("0x%0" PRIx64, Val);
-    return;
-  }
-
-  if (isExtern) {
-    symbol_iterator SI = O->symbol_begin();
-    advance(SI, Val);
-    Expected<StringRef> SOrErr = SI->getName();
-    if (!SOrErr)
-      report_error(O->getFileName(), SOrErr.takeError());
-    S = *SOrErr;
-  } else {
-    section_iterator SI = O->section_begin();
-    // Adjust for the fact that sections are 1-indexed.
-    if (Val == 0) {
-      Fmt << "0 (?,?)";
-      return;
-    }
-    uint32_t I = Val - 1;
-    while (I != 0 && SI != O->section_end()) {
-      --I;
-      advance(SI, 1);
-    }
-    if (SI == O->section_end())
-      Fmt << Val << " (?,?)";
-    else
-      SI->getName(S);
-  }
-
-  Fmt << S;
-}
-
-static std::error_code getRelocationValueString(const WasmObjectFile *Obj,
-                                                const RelocationRef &RelRef,
-                                                SmallVectorImpl<char> &Result) {
-  const wasm::WasmRelocation& Rel = Obj->getWasmRelocation(RelRef);
-  symbol_iterator SI = RelRef.getSymbol();
-  std::string FmtBuf;
-  raw_string_ostream Fmt(FmtBuf);
-  if (SI == Obj->symbol_end()) {
-    // Not all wasm relocations have symbols associated with them.
-    // In particular R_WEBASSEMBLY_TYPE_INDEX_LEB.
-    Fmt << Rel.Index;
-  } else {
-    Expected<StringRef> SymNameOrErr = SI->getName();
-    if (!SymNameOrErr)
-      return errorToErrorCode(SymNameOrErr.takeError());
-    StringRef SymName = *SymNameOrErr;
-    Result.append(SymName.begin(), SymName.end());
-  }
-  Fmt << (Rel.Addend < 0 ? "" : "+") << Rel.Addend;
-  Fmt.flush();
-  Result.append(FmtBuf.begin(), FmtBuf.end());
-  return std::error_code();
-}
-
-static std::error_code getRelocationValueString(const MachOObjectFile *Obj,
-                                                const RelocationRef &RelRef,
-                                                SmallVectorImpl<char> &Result) {
-  DataRefImpl Rel = RelRef.getRawDataRefImpl();
-  MachO::any_relocation_info RE = Obj->getRelocation(Rel);
-
-  unsigned Arch = Obj->getArch();
-
-  std::string FmtBuf;
-  raw_string_ostream Fmt(FmtBuf);
-  unsigned Type = Obj->getAnyRelocationType(RE);
-  bool IsPCRel = Obj->getAnyRelocationPCRel(RE);
-
-  // Determine any addends that should be displayed with the relocation.
-  // These require decoding the relocation type, which is triple-specific.
-
-  // X86_64 has entirely custom relocation types.
-  if (Arch == Triple::x86_64) {
-    switch (Type) {
-    case MachO::X86_64_RELOC_GOT_LOAD:
-    case MachO::X86_64_RELOC_GOT: {
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "@GOT";
-      if (IsPCRel)
-        Fmt << "PCREL";
-      break;
-    }
-    case MachO::X86_64_RELOC_SUBTRACTOR: {
-      DataRefImpl RelNext = Rel;
-      Obj->moveRelocationNext(RelNext);
-      MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
-
-      // X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
-      // X86_64_RELOC_UNSIGNED.
-      // NOTE: Scattered relocations don't exist on x86_64.
-      unsigned RType = Obj->getAnyRelocationType(RENext);
-      if (RType != MachO::X86_64_RELOC_UNSIGNED)
-        report_error(Obj->getFileName(), "Expected X86_64_RELOC_UNSIGNED after "
-                     "X86_64_RELOC_SUBTRACTOR.");
-
-      // The X86_64_RELOC_UNSIGNED contains the minuend symbol;
-      // X86_64_RELOC_SUBTRACTOR contains the subtrahend.
-      printRelocationTargetName(Obj, RENext, Fmt);
-      Fmt << "-";
-      printRelocationTargetName(Obj, RE, Fmt);
-      break;
-    }
-    case MachO::X86_64_RELOC_TLV:
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "@TLV";
-      if (IsPCRel)
-        Fmt << "P";
-      break;
-    case MachO::X86_64_RELOC_SIGNED_1:
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "-1";
-      break;
-    case MachO::X86_64_RELOC_SIGNED_2:
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "-2";
-      break;
-    case MachO::X86_64_RELOC_SIGNED_4:
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "-4";
-      break;
-    default:
-      printRelocationTargetName(Obj, RE, Fmt);
-      break;
-    }
-    // X86 and ARM share some relocation types in common.
-  } else if (Arch == Triple::x86 || Arch == Triple::arm ||
-             Arch == Triple::ppc) {
-    // Generic relocation types...
-    switch (Type) {
-    case MachO::GENERIC_RELOC_PAIR: // prints no info
-      return std::error_code();
-    case MachO::GENERIC_RELOC_SECTDIFF: {
-      DataRefImpl RelNext = Rel;
-      Obj->moveRelocationNext(RelNext);
-      MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
-
-      // X86 sect diff's must be followed by a relocation of type
-      // GENERIC_RELOC_PAIR.
-      unsigned RType = Obj->getAnyRelocationType(RENext);
-
-      if (RType != MachO::GENERIC_RELOC_PAIR)
-        report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
-                     "GENERIC_RELOC_SECTDIFF.");
-
-      printRelocationTargetName(Obj, RE, Fmt);
-      Fmt << "-";
-      printRelocationTargetName(Obj, RENext, Fmt);
-      break;
-    }
-    }
-
-    if (Arch == Triple::x86 || Arch == Triple::ppc) {
-      switch (Type) {
-      case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
-        DataRefImpl RelNext = Rel;
-        Obj->moveRelocationNext(RelNext);
-        MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
-
-        // X86 sect diff's must be followed by a relocation of type
-        // GENERIC_RELOC_PAIR.
-        unsigned RType = Obj->getAnyRelocationType(RENext);
-        if (RType != MachO::GENERIC_RELOC_PAIR)
-          report_error(Obj->getFileName(), "Expected GENERIC_RELOC_PAIR after "
-                       "GENERIC_RELOC_LOCAL_SECTDIFF.");
-
-        printRelocationTargetName(Obj, RE, Fmt);
-        Fmt << "-";
-        printRelocationTargetName(Obj, RENext, Fmt);
-        break;
-      }
-      case MachO::GENERIC_RELOC_TLV: {
-        printRelocationTargetName(Obj, RE, Fmt);
-        Fmt << "@TLV";
-        if (IsPCRel)
-          Fmt << "P";
-        break;
-      }
-      default:
-        printRelocationTargetName(Obj, RE, Fmt);
-      }
-    } else { // ARM-specific relocations
-      switch (Type) {
-      case MachO::ARM_RELOC_HALF:
-      case MachO::ARM_RELOC_HALF_SECTDIFF: {
-        // Half relocations steal a bit from the length field to encode
-        // whether this is an upper16 or a lower16 relocation.
-        bool isUpper = (Obj->getAnyRelocationLength(RE) & 0x1) == 1;
-
-        if (isUpper)
-          Fmt << ":upper16:(";
-        else
-          Fmt << ":lower16:(";
-        printRelocationTargetName(Obj, RE, Fmt);
-
-        DataRefImpl RelNext = Rel;
-        Obj->moveRelocationNext(RelNext);
-        MachO::any_relocation_info RENext = Obj->getRelocation(RelNext);
-
-        // ARM half relocs must be followed by a relocation of type
-        // ARM_RELOC_PAIR.
-        unsigned RType = Obj->getAnyRelocationType(RENext);
-        if (RType != MachO::ARM_RELOC_PAIR)
-          report_error(Obj->getFileName(), "Expected ARM_RELOC_PAIR after "
-                       "ARM_RELOC_HALF");
-
-        // NOTE: The half of the target virtual address is stashed in the
-        // address field of the secondary relocation, but we can't reverse
-        // engineer the constant offset from it without decoding the movw/movt
-        // instruction to find the other half in its immediate field.
-
-        // ARM_RELOC_HALF_SECTDIFF encodes the second section in the
-        // symbol/section pointer of the follow-on relocation.
-        if (Type == MachO::ARM_RELOC_HALF_SECTDIFF) {
-          Fmt << "-";
-          printRelocationTargetName(Obj, RENext, Fmt);
-        }
-
-        Fmt << ")";
-        break;
-      }
-      default: { printRelocationTargetName(Obj, RE, Fmt); }
-      }
-    }
-  } else
-    printRelocationTargetName(Obj, RE, Fmt);
-
-  Fmt.flush();
-  Result.append(FmtBuf.begin(), FmtBuf.end());
-  return std::error_code();
-}
-
 static std::error_code getRelocationValueString(const RelocationRef &Rel,
                                                 SmallVectorImpl<char> &Result) {
   const ObjectFile *Obj = Rel.getObject();
   if (auto *ELF = dyn_cast<ELFObjectFileBase>(Obj))
-    return getRelocationValueString(ELF, Rel, Result);
+    return getELFRelocationValueString(ELF, Rel, Result);
   if (auto *COFF = dyn_cast<COFFObjectFile>(Obj))
-    return getRelocationValueString(COFF, Rel, Result);
+    return getCOFFRelocationValueString(COFF, Rel, Result);
   if (auto *Wasm = dyn_cast<WasmObjectFile>(Obj))
-    return getRelocationValueString(Wasm, Rel, Result);
+    return getWasmRelocationValueString(Wasm, Rel, Result);
   if (auto *MachO = dyn_cast<MachOObjectFile>(Obj))
-    return getRelocationValueString(MachO, Rel, Result);
+    return getMachORelocationValueString(MachO, Rel, Result);
   llvm_unreachable("unknown object file format");
 }
 
 /// Indicates whether this relocation should hidden when listing
 /// relocations, usually because it is the trailing part of a multipart
 /// relocation that will be printed as part of the leading relocation.
 static bool getHidden(RelocationRef RelRef) {
   auto *MachO = dyn_cast<MachOObjectFile>(RelRef.getObject());