[llvm-nm] - Move MachO specific logic out from the dumpSymbolNamesFromObject(). NFC.

[grimar]

Summary

dumpSymbolNamesFromObject is the method that dumps symbol names.

It has 563 lines, mostly because of huge piece of MachO specific code.
In this patch I move it to separate helper method.

The new size of dumpSymbolNamesFromObject is 93 lines. With it it becomes
much easier to maintain it.

I had to change the type of 2 name fields to std::string, because MachO logic
uses temporarily buffer strings (e.g ExportsNameBuffer, BindsNameBuffer etc):

std::string ExportsNameBuffer;
raw_string_ostream EOS(ExportsNameBuffer);

these buffers were moved to dumpSymbolsFromDLInfoMachO by this patch and
are invalidated after return. Technically, before this patch we had a situation
when local pointers (symbol names) were assigned to members of global static SymbolList,
what is dirty by itself.

[jhenderson]

llvm/tools/llvm-nm/llvm-nm.cpp

1320

Whilst you're here, you could get rid of the unnecessary const & here, if you want.

1689

Is everything in this function essentially identical to what was there before (barring the new call)? For some reason, Phabricator isn't showing the "moved" marker, so I can't tell.

[grimar]

llvm/tools/llvm-nm/llvm-nm.cpp

1689

Yes.

Previously we had

if (MachO && !NoDyldInfo) {
  <logic>
}

and now we have:

if (MachO && !NoDyldInfo)
  dumpSymbolsFromDLInfoMachO(*MachO);

It is the only difference.

[jhenderson]

Okay, LGTM!

[grimar]

llvm/tools/llvm-nm/llvm-nm.cpp

1689

Oh, and

std::string ExportsNameBuffer;
raw_string_ostream EOS(ExportsNameBuffer);
std::string BindsNameBuffer;
raw_string_ostream BOS(BindsNameBuffer);
std::string LazysNameBuffer;
raw_string_ostream LOS(LazysNameBuffer);
std::string WeaksNameBuffer;
raw_string_ostream WOS(WeaksNameBuffer);
std::string FunctionStartsNameBuffer;
raw_string_ostream FOS(FunctionStartsNameBuffer);

declarations were also moved to dumpSymbolsFromDLInfoMachO of course,

[tschuett]

Does it have to stay in llvm-nm.cpp? A different file for MachO stuff?

[grimar]

In D94667#2498005, @tschuett wrote:

Does it have to stay in llvm-nm.cpp? A different file for MachO stuff?

It seems possible to move some MachO specific stuff to a different file. This is out of scope of this patch though.

[MaskRay]

LGTM.

llvm/tools/llvm-nm/llvm-nm.cpp

static void error(llvm::Error E, StringRef FileName,
   errs() << " " << Buf << "\n";
 }
 
 namespace {
 struct NMSymbol {
   uint64_t Address;
   uint64_t Size;
   char TypeChar;
-  StringRef Name;
+  std::string Name;
   StringRef SectionName;
   StringRef TypeName;
   BasicSymbolRef Sym;
   // The Sym field above points to the native symbol in the object file,
   // for Mach-O when we are creating symbols from the dyld info the above
   // pointer is null as there is no native symbol.  In these cases the fields
   // below are filled in to represent what would have been a Mach-O nlist
   // native symbol.
   uint32_t SymFlags;
   SectionRef Section;
   uint8_t NType;
   uint8_t NSect;
   uint16_t NDesc;
-  StringRef IndirectName;
+  std::string IndirectName;
 };
 } // anonymous namespace
 
 static bool compareSymbolAddress(const NMSymbol &A, const NMSymbol &B) {
   bool ADefined;
   // Symbol flags have been checked in the caller.
   if (A.Sym.getRawDataRefImpl().p) {
     uint32_t AFlags = cantFail(A.Sym.getFlags());
case Radix::x:
       break;
     default:
       printFormat = OutputFormat == posix ? "%" PRId64 : "%08" PRId64;
     }
   }
 
   for (const NMSymbol &S : SymbolList) {
     uint32_t SymFlags;
-    std::string Name = S.Name.str();
+    std::string Name = S.Name;
     MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(&Obj);
     if (Demangle) {
       if (Optional<std::string> Opt = demangle(S.Name, MachO))
         Name = *Opt;
     }
     if (S.Sym.getRawDataRefImpl().p) {
       Expected<uint32_t> SymFlagsOrErr = S.Sym.getFlags();
       if (!SymFlagsOrErr) {
static unsigned getNsectInMachO(MachOObjectFile &Obj, BasicSymbolRef Sym) {
   if (Obj.is64Bit()) {
     MachO::nlist_64 STE = Obj.getSymbol64TableEntry(Symb);
     return (STE.n_type & MachO::N_TYPE) == MachO::N_SECT ? STE.n_sect : 0;
   }
   MachO::nlist STE = Obj.getSymbolTableEntry(Symb);
   return (STE.n_type & MachO::N_TYPE) == MachO::N_SECT ? STE.n_sect : 0;
 }
 
-static void dumpSymbolNamesFromObject(SymbolicFile &Obj, bool printName,
-                                      StringRef ArchiveName = {},
-                                      StringRef ArchitectureName = {}) {
-  auto Symbols = Obj.symbols();
-  if (DynamicSyms) {
-    const auto *E = dyn_cast<ELFObjectFileBase>(&Obj);
-    if (!E) {
-      error("File format has no dynamic symbol table", Obj.getFileName());
-      return;
-    }
-    Symbols = E->getDynamicSymbolIterators();
-  }
-  std::string NameBuffer;
-  raw_string_ostream OS(NameBuffer);
-  // If a "-s segname sectname" option was specified and this is a Mach-O
-  // file get the section number for that section in this object file.
-  unsigned int Nsect = 0;
-  MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(&Obj);
-  if (!SegSect.empty() && MachO) {
-    Nsect = getNsectForSegSect(MachO);
-    // If this section is not in the object file no symbols are printed.
-    if (Nsect == 0)
-      return;
-  }
-  if (!(MachO && DyldInfoOnly)) {
-    for (BasicSymbolRef Sym : Symbols) {
-      Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
-      if (!SymFlagsOrErr) {
-        error(SymFlagsOrErr.takeError(), Obj.getFileName());
-        return;
-      }
-      if (!DebugSyms && (*SymFlagsOrErr & SymbolRef::SF_FormatSpecific))
-        continue;
-      if (WithoutAliases && (*SymFlagsOrErr & SymbolRef::SF_Indirect))
-        continue;
-      // If a "-s segname sectname" option was specified and this is a Mach-O
-      // file and this section appears in this file, Nsect will be non-zero then
-      // see if this symbol is a symbol from that section and if not skip it.
-      if (Nsect && Nsect != getNsectInMachO(*MachO, Sym))
-        continue;
-      NMSymbol S = {};
-      S.Size = 0;
-      S.Address = 0;
-      if (isa<ELFObjectFileBase>(&Obj))
-        S.Size = ELFSymbolRef(Sym).getSize();
-      if (PrintAddress && isa<ObjectFile>(Obj)) {
-        SymbolRef SymRef(Sym);
-        Expected<uint64_t> AddressOrErr = SymRef.getAddress();
-        if (!AddressOrErr) {
-          consumeError(AddressOrErr.takeError());
-          break;
-        }
-        S.Address = *AddressOrErr;
-      }
-      S.TypeName = getNMTypeName(Obj, Sym);
-      S.TypeChar = getNMSectionTagAndName(Obj, Sym, S.SectionName);
-      if (Error E = Sym.printName(OS)) {
-        if (MachO) {
-          OS << "bad string index";
-          consumeError(std::move(E));
-        } else
-          error(std::move(E), Obj.getFileName());
-      }
-      OS << '\0';
-      S.Sym = Sym;
-      SymbolList.push_back(S);
-    }
-  }
-
-  OS.flush();
-  const char *P = NameBuffer.c_str();
-  unsigned I;
-  for (I = 0; I < SymbolList.size(); ++I) {
-    SymbolList[I].Name = P;
-    P += strlen(P) + 1;
-  }
-
-  // If this is a Mach-O file where the nlist symbol table is out of sync
-  // with the dyld export trie then look through exports and fake up symbols
-  // for the ones that are missing (also done with the -add-dyldinfo flag).
-  // This is needed if strip(1) -T is run on a binary containing swift
-  // language symbols for example.  The option -only-dyldinfo will fake up
-  // all symbols from the dyld export trie as well as the bind info.
+static void dumpSymbolsFromDLInfoMachO(MachOObjectFile &MachO) {
+  size_t I = SymbolList.size();
   std::string ExportsNameBuffer;
   raw_string_ostream EOS(ExportsNameBuffer);
   std::string BindsNameBuffer;
   raw_string_ostream BOS(BindsNameBuffer);
   std::string LazysNameBuffer;
   raw_string_ostream LOS(LazysNameBuffer);
   std::string WeaksNameBuffer;
   raw_string_ostream WOS(WeaksNameBuffer);
   std::string FunctionStartsNameBuffer;
   raw_string_ostream FOS(FunctionStartsNameBuffer);
-  if (MachO && !NoDyldInfo) {
-    MachO::mach_header H;
-    MachO::mach_header_64 H_64;
-    uint32_t HFlags = 0;
-    if (MachO->is64Bit()) {
-      H_64 = MachO->MachOObjectFile::getHeader64();
-      HFlags = H_64.flags;
-    } else {
-      H = MachO->MachOObjectFile::getHeader();
-      HFlags = H.flags;
-    }
-    uint64_t BaseSegmentAddress = 0;
-    for (const auto &Command : MachO->load_commands()) {
-      if (Command.C.cmd == MachO::LC_SEGMENT) {
-        MachO::segment_command Seg = MachO->getSegmentLoadCommand(Command);
-        if (Seg.fileoff == 0 && Seg.filesize != 0) {
-          BaseSegmentAddress = Seg.vmaddr;
-          break;
-        }
-      } else if (Command.C.cmd == MachO::LC_SEGMENT_64) {
-        MachO::segment_command_64 Seg = MachO->getSegment64LoadCommand(Command);
-        if (Seg.fileoff == 0 && Seg.filesize != 0) {
-          BaseSegmentAddress = Seg.vmaddr;
-          break;
-        }
-      }
-    }
-    if (DyldInfoOnly || AddDyldInfo ||
-        HFlags & MachO::MH_NLIST_OUTOFSYNC_WITH_DYLDINFO) {
-      unsigned ExportsAdded = 0;
-      Error Err = Error::success();
-      for (const llvm::object::ExportEntry &Entry : MachO->exports(Err)) {
-        bool found = false;
-        bool ReExport = false;
-        if (!DyldInfoOnly) {
-          for (const NMSymbol &S : SymbolList)
-            if (S.Address == Entry.address() + BaseSegmentAddress &&
-                S.Name == Entry.name()) {
-              found = true;
-              break;
-            }
-        }
-        if (!found) {
-          NMSymbol S = {};
-          S.Address = Entry.address() + BaseSegmentAddress;
-          S.Size = 0;
-          S.TypeChar = '\0';
-          S.Name = Entry.name();
-          // There is no symbol in the nlist symbol table for this so we set
-          // Sym effectivly to null and the rest of code in here must test for
-          // it and not do things like Sym.getFlags() for it.
-          S.Sym = BasicSymbolRef();
-          S.SymFlags = SymbolRef::SF_Global;
-          S.Section = SectionRef();
-          S.NType = 0;
-          S.NSect = 0;
-          S.NDesc = 0;
-          S.IndirectName = StringRef();
+
+  if (MachO.is64Bit()) {
+    H_64 = MachO.MachOObjectFile::getHeader64();
+    H = MachO.MachOObjectFile::getHeader();
+  for (const auto &Command : MachO.load_commands()) {
+      MachO::segment_command Seg = MachO.getSegmentLoadCommand(Command);
+      MachO::segment_command_64 Seg = MachO.getSegment64LoadCommand(Command);
+    for (const llvm::object::ExportEntry &Entry : MachO.exports(Err)) {
+        S.Name = Entry.name().str();
 
-          uint64_t EFlags = Entry.flags();
-          bool Abs = ((EFlags & MachO::EXPORT_SYMBOL_FLAGS_KIND_MASK) ==
-                      MachO::EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE);
-          bool Resolver = (EFlags &
-                           MachO::EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER);
-          ReExport = (EFlags & MachO::EXPORT_SYMBOL_FLAGS_REEXPORT);
-          bool WeakDef = (EFlags & MachO::EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION);
-          if (WeakDef)
-            S.NDesc |= MachO::N_WEAK_DEF;
-          if (Abs) {
-            S.NType = MachO::N_EXT | MachO::N_ABS;
-            S.TypeChar = 'A';
-          } else if (ReExport) {
-            S.NType = MachO::N_EXT | MachO::N_INDR;
-            S.TypeChar = 'I';
-          } else {
-            S.NType = MachO::N_EXT | MachO::N_SECT;
-            if (Resolver) {
-              S.Address = Entry.other() + BaseSegmentAddress;
-              if ((S.Address & 1) != 0 &&
-                  !MachO->is64Bit() && H.cputype == MachO::CPU_TYPE_ARM){
-                S.Address &= ~1LL;
-                S.NDesc |= MachO::N_ARM_THUMB_DEF;
-              }
-            } else {
-              S.Address = Entry.address() + BaseSegmentAddress;
-            }
-            StringRef SegmentName = StringRef();
-            StringRef SectionName = StringRef();
-            for (const SectionRef &Section : MachO->sections()) {
-              S.NSect++;
- 
-              if (Expected<StringRef> NameOrErr = Section.getName())
-                SectionName = *NameOrErr;
-              else
-                consumeError(NameOrErr.takeError());
+        bool Resolver = (EFlags & MachO::EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER);
+            if ((S.Address & 1) != 0 && !MachO.is64Bit() &&
+                H.cputype == MachO::CPU_TYPE_ARM) {
+          for (const SectionRef &Section : MachO.sections()) {
 
-              SegmentName = MachO->getSectionFinalSegmentName(
-                                                  Section.getRawDataRefImpl());
-              if (S.Address >= Section.getAddress() &&
-                  S.Address < Section.getAddress() + Section.getSize()) {
-                S.Section = Section;
-                break;
-              } else if (Entry.name() == "__mh_execute_header" &&
-                         SegmentName == "__TEXT" && SectionName == "__text") {
-                S.Section = Section;
-                S.NDesc |= MachO::REFERENCED_DYNAMICALLY;
-                break;
-              }
-            }
-            if (SegmentName == "__TEXT" && SectionName == "__text")
-              S.TypeChar = 'T';
-            else if (SegmentName == "__DATA" && SectionName == "__data")
-              S.TypeChar = 'D';
-            else if (SegmentName == "__DATA" && SectionName == "__bss")
-              S.TypeChar = 'B';
-            else
-              S.TypeChar = 'S';
-          }
-          SymbolList.push_back(S);
+            SegmentName =
+                MachO.getSectionFinalSegmentName(Section.getRawDataRefImpl());
 
-          EOS << Entry.name();
-          EOS << '\0';
-          ExportsAdded++;
 
-          // For ReExports there are a two more things to do, first add the
-          // indirect name and second create the undefined symbol using the
-          // referened dynamic library.
-          if (ReExport) {
 
-            // Add the indirect name.
-            if (Entry.otherName().empty())
-              EOS << Entry.name();
-            else
-              EOS << Entry.otherName();
-            EOS << '\0';
 
-            // Now create the undefined symbol using the referened dynamic
-            // library.
-            NMSymbol U = {};
-            U.Address = 0;
-            U.Size = 0;
-            U.TypeChar = 'U';
-            if (Entry.otherName().empty())
-              U.Name = Entry.name();
-            else
-              U.Name = Entry.otherName();
-            // Again there is no symbol in the nlist symbol table for this so
-            // we set Sym effectivly to null and the rest of code in here must
-            // test for it and not do things like Sym.getFlags() for it.
-            U.Sym = BasicSymbolRef();
-            U.SymFlags = SymbolRef::SF_Global | SymbolRef::SF_Undefined;
-            U.Section = SectionRef();
-            U.NType = MachO::N_EXT | MachO::N_UNDF;
-            U.NSect = 0;
-            U.NDesc = 0;
-            // The library ordinal for this undefined symbol is in the export
-            // trie Entry.other().
-            MachO::SET_LIBRARY_ORDINAL(U.NDesc, Entry.other());
-            U.IndirectName = StringRef();
-            SymbolList.push_back(U);
+            U.Name = Entry.name().str();
+            U.Name = Entry.otherName().str();
 
-            // Finally add the undefined symbol's name.
-            if (Entry.otherName().empty())
-              EOS << Entry.name();
-            else
-              EOS << Entry.otherName();
-            EOS << '\0';
-            ExportsAdded++;
-          }
-        }
-      }
-      if (Err)
-        error(std::move(Err), MachO->getFileName());
-      // Set the symbol names and indirect names for the added symbols.
-      if (ExportsAdded) {
-        EOS.flush();
-        const char *Q = ExportsNameBuffer.c_str();
-        for (unsigned K = 0; K < ExportsAdded; K++) {
-          SymbolList[I].Name = Q;
-          Q += strlen(Q) + 1;
-          if (SymbolList[I].TypeChar == 'I') {
-            SymbolList[I].IndirectName = Q;
-            Q += strlen(Q) + 1;
-          }
-          I++;
-        }
-      }
+      error(std::move(Err), MachO.getFileName());
 
-      // Add the undefined symbols from the bind entries.
-      unsigned BindsAdded = 0;
-      Error BErr = Error::success();
-      StringRef LastSymbolName = StringRef();
-      for (const llvm::object::MachOBindEntry &Entry : MachO->bindTable(BErr)) {
-        bool found = false;
-        if (LastSymbolName == Entry.symbolName())
-          found = true;
-        else if(!DyldInfoOnly) {
-          for (unsigned J = 0; J < SymbolList.size() && !found; ++J) {
-            if (SymbolList[J].Name == Entry.symbolName())
-              found = true;
-          }
-        }
-        if (!found) {
-          LastSymbolName = Entry.symbolName();
-          NMSymbol B = {};
-          B.Address = 0;
-          B.Size = 0;
-          B.TypeChar = 'U';
-          // There is no symbol in the nlist symbol table for this so we set
-          // Sym effectivly to null and the rest of code in here must test for
-          // it and not do things like Sym.getFlags() for it.
-          B.Sym = BasicSymbolRef();
-          B.SymFlags = SymbolRef::SF_Global | SymbolRef::SF_Undefined;
-          B.NType = MachO::N_EXT | MachO::N_UNDF;
-          B.NSect = 0;
-          B.NDesc = 0;
-          MachO::SET_LIBRARY_ORDINAL(B.NDesc, Entry.ordinal());
-          B.IndirectName = StringRef();
-          B.Name = Entry.symbolName();
-          SymbolList.push_back(B);
-          BOS << Entry.symbolName();
-          BOS << '\0';
-          BindsAdded++;
-        }
-      }
-      if (BErr)
-        error(std::move(BErr), MachO->getFileName());
-      // Set the symbol names and indirect names for the added symbols.
-      if (BindsAdded) {
-        BOS.flush();
-        const char *Q = BindsNameBuffer.c_str();
-        for (unsigned K = 0; K < BindsAdded; K++) {
-          SymbolList[I].Name = Q;
-          Q += strlen(Q) + 1;
-          if (SymbolList[I].TypeChar == 'I') {
-            SymbolList[I].IndirectName = Q;
-            Q += strlen(Q) + 1;
-          }
-          I++;
-        }
-      }
+    for (const llvm::object::MachOBindEntry &Entry : MachO.bindTable(BErr)) {
+      else if (!DyldInfoOnly) {
+        B.Name = Entry.symbolName().str();
+      error(std::move(BErr), MachO.getFileName());
 
-      // Add the undefined symbols from the lazy bind entries.
-      unsigned LazysAdded = 0;
-      Error LErr = Error::success();
-      LastSymbolName = StringRef();
-      for (const llvm::object::MachOBindEntry &Entry :
-           MachO->lazyBindTable(LErr)) {
-        bool found = false;
-        if (LastSymbolName == Entry.symbolName())
-          found = true;
-        else {
-          // Here we must check to see it this symbol is already in the
-          // SymbolList as it might have already have been added above via a
-          // non-lazy (bind) entry.
-          for (unsigned J = 0; J < SymbolList.size() && !found; ++J) {
-            if (SymbolList[J].Name == Entry.symbolName())
-              found = true;
-          }
-        }
-        if (!found) {
-          LastSymbolName = Entry.symbolName();
-          NMSymbol L = {};
-          L.Name = Entry.symbolName();
-          L.Address = 0;
-          L.Size = 0;
-          L.TypeChar = 'U';
-          // There is no symbol in the nlist symbol table for this so we set
-          // Sym effectivly to null and the rest of code in here must test for
-          // it and not do things like Sym.getFlags() for it.
-          L.Sym = BasicSymbolRef();
-          L.SymFlags = SymbolRef::SF_Global | SymbolRef::SF_Undefined;
-          L.NType = MachO::N_EXT | MachO::N_UNDF;
-          L.NSect = 0;
-          // The REFERENCE_FLAG_UNDEFINED_LAZY is no longer used but here it
-          // makes sence since we are creating this from a lazy bind entry.
-          L.NDesc = MachO::REFERENCE_FLAG_UNDEFINED_LAZY;
-          MachO::SET_LIBRARY_ORDINAL(L.NDesc, Entry.ordinal());
-          L.IndirectName = StringRef();
-          SymbolList.push_back(L);
-          LOS << Entry.symbolName();
-          LOS << '\0';
-          LazysAdded++;
-        }
-      }
-      if (LErr)
-        error(std::move(LErr), MachO->getFileName());
-      // Set the symbol names and indirect names for the added symbols.
-      if (LazysAdded) {
-        LOS.flush();
-        const char *Q = LazysNameBuffer.c_str();
-        for (unsigned K = 0; K < LazysAdded; K++) {
-          SymbolList[I].Name = Q;
-          Q += strlen(Q) + 1;
-          if (SymbolList[I].TypeChar == 'I') {
-            SymbolList[I].IndirectName = Q;
-            Q += strlen(Q) + 1;
-          }
-          I++;
-        }
-      }
+         MachO.lazyBindTable(LErr)) {
+        L.Name = Entry.symbolName().str();
+      error(std::move(LErr), MachO.getFileName());
 
-      // Add the undefineds symbol from the weak bind entries which are not
-      // strong symbols.
-      unsigned WeaksAdded = 0;
-      Error WErr = Error::success();
-      LastSymbolName = StringRef();
-      for (const llvm::object::MachOBindEntry &Entry :
-           MachO->weakBindTable(WErr)) {
-        bool found = false;
-        unsigned J = 0;
-        if (LastSymbolName == Entry.symbolName() ||
-            Entry.flags() & MachO::BIND_SYMBOL_FLAGS_NON_WEAK_DEFINITION) {
-          found = true;
-        } else {
-          for (J = 0; J < SymbolList.size() && !found; ++J) {
-            if (SymbolList[J].Name == Entry.symbolName()) {
-               found = true;
-               break;
-            }
-          }
-        }
-        if (!found) {
-          LastSymbolName = Entry.symbolName();
-          NMSymbol W = {};
-          W.Name = Entry.symbolName();
-          W.Address = 0;
-          W.Size = 0;
-          W.TypeChar = 'U';
-          // There is no symbol in the nlist symbol table for this so we set
-          // Sym effectivly to null and the rest of code in here must test for
-          // it and not do things like Sym.getFlags() for it.
-          W.Sym = BasicSymbolRef();
-          W.SymFlags = SymbolRef::SF_Global | SymbolRef::SF_Undefined;
-          W.NType = MachO::N_EXT | MachO::N_UNDF;
-          W.NSect = 0;
-          // Odd that we are using N_WEAK_DEF on an undefined symbol but that is
-          // what is created in this case by the linker when there are real
-          // symbols in the nlist structs.
-          W.NDesc = MachO::N_WEAK_DEF;
-          W.IndirectName = StringRef();
-          SymbolList.push_back(W);
-          WOS << Entry.symbolName();
-          WOS << '\0';
-          WeaksAdded++;
-        } else {
-          // This is the case the symbol was previously been found and it could
-          // have been added from a bind or lazy bind symbol.  If so and not
-          // a definition also mark it as weak.
-          if (SymbolList[J].TypeChar == 'U')
-            // See comment above about N_WEAK_DEF.
-            SymbolList[J].NDesc |= MachO::N_WEAK_DEF;
-        }
-      }
-      if (WErr)
-        error(std::move(WErr), MachO->getFileName());
-      // Set the symbol names and indirect names for the added symbols.
-      if (WeaksAdded) {
-        WOS.flush();
-        const char *Q = WeaksNameBuffer.c_str();
-        for (unsigned K = 0; K < WeaksAdded; K++) {
-          SymbolList[I].Name = Q;
-          Q += strlen(Q) + 1;
-          if (SymbolList[I].TypeChar == 'I') {
-            SymbolList[I].IndirectName = Q;
-            Q += strlen(Q) + 1;
-          }
-          I++;
-        }
-      }
+         MachO.weakBindTable(WErr)) {
+        W.Name = Entry.symbolName().str();
+      error(std::move(WErr), MachO.getFileName());
 
-      // Trying adding symbol from the function starts table and LC_MAIN entry
-      // point.
-      SmallVector<uint64_t, 8> FoundFns;
-      uint64_t lc_main_offset = UINT64_MAX;
-      for (const auto &Command : MachO->load_commands()) {
-        if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) {
-          // We found a function starts segment, parse the addresses for
-          // consumption.
-          MachO::linkedit_data_command LLC =
-            MachO->getLinkeditDataLoadCommand(Command);
+    for (const auto &Command : MachO.load_commands()) {
+            MachO.getLinkeditDataLoadCommand(Command);
 
-          MachO->ReadULEB128s(LLC.dataoff, FoundFns);
-        } else if (Command.C.cmd == MachO::LC_MAIN) {
-          MachO::entry_point_command LCmain =
-            MachO->getEntryPointCommand(Command);
-          lc_main_offset = LCmain.entryoff;
-        }
-      }
-      // See if these addresses are already in the symbol table.
-      unsigned FunctionStartsAdded = 0;
-      for (uint64_t f = 0; f < FoundFns.size(); f++) {
-        bool found = false;
-        for (unsigned J = 0; J < SymbolList.size() && !found; ++J) {
-          if (SymbolList[J].Address == FoundFns[f] + BaseSegmentAddress)
-            found = true;
-        }
-        // See this address is not already in the symbol table fake up an
-        // nlist for it.
-        if (!found) {
-          NMSymbol F = {};
-          F.Name = "<redacted function X>";
-          F.Address = FoundFns[f] + BaseSegmentAddress;
-          F.Size = 0;
-          // There is no symbol in the nlist symbol table for this so we set
-          // Sym effectivly to null and the rest of code in here must test for
-          // it and not do things like Sym.getFlags() for it.
-          F.Sym = BasicSymbolRef();
-          F.SymFlags = 0;
-          F.NType = MachO::N_SECT;
-          F.NSect = 0;
-          StringRef SegmentName = StringRef();
-          StringRef SectionName = StringRef();
-          for (const SectionRef &Section : MachO->sections()) {
-            if (Expected<StringRef> NameOrErr = Section.getName())
-              SectionName = *NameOrErr;
-            else
-              consumeError(NameOrErr.takeError());
+        MachO.ReadULEB128s(LLC.dataoff, FoundFns);
+        MachO::entry_point_command LCmain = MachO.getEntryPointCommand(Command);
+        for (const SectionRef &Section : MachO.sections()) {
 
-            SegmentName = MachO->getSectionFinalSegmentName(
-                                                Section.getRawDataRefImpl());
-            F.NSect++;
-            if (F.Address >= Section.getAddress() &&
-                F.Address < Section.getAddress() + Section.getSize()) {
-              F.Section = Section;
-              break;
-            }
-          }
-          if (SegmentName == "__TEXT" && SectionName == "__text")
-            F.TypeChar = 't';
-          else if (SegmentName == "__DATA" && SectionName == "__data")
-            F.TypeChar = 'd';
-          else if (SegmentName == "__DATA" && SectionName == "__bss")
-            F.TypeChar = 'b';
-          else
-            F.TypeChar = 's';
-          F.NDesc = 0;
-          F.IndirectName = StringRef();
-          SymbolList.push_back(F);
-          if (FoundFns[f] == lc_main_offset)
-            FOS << "<redacted LC_MAIN>";
-          else
-            FOS << "<redacted function " << f << ">";
-          FOS << '\0';
-          FunctionStartsAdded++;
-        }
-      }
-      if (FunctionStartsAdded) {
-        FOS.flush();
-        const char *Q = FunctionStartsNameBuffer.c_str();
-        for (unsigned K = 0; K < FunctionStartsAdded; K++) {
-          SymbolList[I].Name = Q;
-          Q += strlen(Q) + 1;
-          if (SymbolList[I].TypeChar == 'I') {
-            SymbolList[I].IndirectName = Q;
-            Q += strlen(Q) + 1;
-          }
-          I++;
-        }
-      }
-    }
-  }
+          SegmentName =
+              MachO.getSectionFinalSegmentName(Section.getRawDataRefImpl());
 
+static void dumpSymbolNamesFromObject(SymbolicFile &Obj, bool printName,
+                                      StringRef ArchiveName = {},
+                                      StringRef ArchitectureName = {}) {
+  auto Symbols = Obj.symbols();
+  if (DynamicSyms) {
+    const auto *E = dyn_cast<ELFObjectFileBase>(&Obj);
+    if (!E) {
+      error("File format has no dynamic symbol table", Obj.getFileName());
+      return;
+    }
+    Symbols = E->getDynamicSymbolIterators();
+  }
+  std::string NameBuffer;
+  raw_string_ostream OS(NameBuffer);
+  // If a "-s segname sectname" option was specified and this is a Mach-O
+  // file get the section number for that section in this object file.
+  unsigned int Nsect = 0;
+  MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(&Obj);
+  if (!SegSect.empty() && MachO) {
+    Nsect = getNsectForSegSect(MachO);
+    // If this section is not in the object file no symbols are printed.
+    if (Nsect == 0)
+      return;
+  }
+  if (!(MachO && DyldInfoOnly)) {
+    for (BasicSymbolRef Sym : Symbols) {
+      Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
+      if (!SymFlagsOrErr) {
+        error(SymFlagsOrErr.takeError(), Obj.getFileName());
+        return;
+      }
+      if (!DebugSyms && (*SymFlagsOrErr & SymbolRef::SF_FormatSpecific))
+        continue;
+      if (WithoutAliases && (*SymFlagsOrErr & SymbolRef::SF_Indirect))
+        continue;
+      // If a "-s segname sectname" option was specified and this is a Mach-O
+      // file and this section appears in this file, Nsect will be non-zero then
+      // see if this symbol is a symbol from that section and if not skip it.
+      if (Nsect && Nsect != getNsectInMachO(*MachO, Sym))
+        continue;
+      NMSymbol S = {};
+      S.Size = 0;
+      S.Address = 0;
+      if (isa<ELFObjectFileBase>(&Obj))
+        S.Size = ELFSymbolRef(Sym).getSize();
+      if (PrintAddress && isa<ObjectFile>(Obj)) {
+        SymbolRef SymRef(Sym);
+        Expected<uint64_t> AddressOrErr = SymRef.getAddress();
+        if (!AddressOrErr) {
+          consumeError(AddressOrErr.takeError());
+          break;
+        }
+        S.Address = *AddressOrErr;
+      }
+      S.TypeName = getNMTypeName(Obj, Sym);
+      S.TypeChar = getNMSectionTagAndName(Obj, Sym, S.SectionName);
+      if (Error E = Sym.printName(OS)) {
+        if (MachO) {
+          OS << "bad string index";
+          consumeError(std::move(E));
+        } else
+          error(std::move(E), Obj.getFileName());
+      }
+      OS << '\0';
+      S.Sym = Sym;
+      SymbolList.push_back(S);
+    }
+  }
+
+  OS.flush();
+  const char *P = NameBuffer.c_str();
+  unsigned I;
+  for (I = 0; I < SymbolList.size(); ++I) {
+    SymbolList[I].Name = P;
+    P += strlen(P) + 1;
+  }
+
+  // If this is a Mach-O file where the nlist symbol table is out of sync
+  // with the dyld export trie then look through exports and fake up symbols
+  // for the ones that are missing (also done with the -add-dyldinfo flag).
+  // This is needed if strip(1) -T is run on a binary containing swift
+  // language symbols for example.  The option -only-dyldinfo will fake up
+  // all symbols from the dyld export trie as well as the bind info.
+  if (MachO && !NoDyldInfo)
+    dumpSymbolsFromDLInfoMachO(*MachO);
+
   CurrentFilename = Obj.getFileName();
 
   if (Symbols.empty() && SymbolList.empty()) {
     writeFileName(errs(), ArchiveName, ArchitectureName);
     errs() << "no symbols\n";
   }
 
   sortAndPrintSymbolList(Obj, printName, ArchiveName, ArchitectureName);