Add "-format darwin" to llvm-nm to be like darwin's nm(1) -m output.

This is a first step in seeing if it is possible to make llvm-nm produce
the same output as darwin's nm(1).  Darwin's default format is bsd but its
-m output prints the longer Mach-O specific details.  For now I added the
"-format darwin" to do this (whos name may need to change in the future).
As there are other Mach-O specific flags to nm(1) which I'm hoping to add some
how in the future.  But I wanted to see if I could get the correct output for
-m flag using llvm-nm and the libObject interfaces.

I got this working but would love to hear what others think about this approach
to getting object/format specific details printed with llvm-nm.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210285 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 486 insertions, 7 deletions

diff --git a/include/llvm/Object/MachO.h b/include/llvm/Object/MachO.h
index 710ad7ef15..ab5b462e01 100644
--- a/include/llvm/Object/MachO.h
+++ b/include/llvm/Object/MachO.h
@@ -61,6 +61,10 @@ public:
 
   void moveSymbolNext(DataRefImpl &Symb) const override;
   error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const override;
+
+  // MachO specific.
+  error_code getIndirectName(DataRefImpl Symb, StringRef &Res) const;
+
   error_code getSymbolAddress(DataRefImpl Symb, uint64_t &Res) const override;
   error_code getSymbolAlignment(DataRefImpl Symb, uint32_t &Res) const override;
   error_code getSymbolSize(DataRefImpl Symb, uint64_t &Res) const override;
@@ -105,6 +109,9 @@ public:
                             LibraryRef &Res) const override;
   error_code getLibraryPath(DataRefImpl LibData, StringRef &Res) const override;
 
+  // MachO specific.
+  error_code getLibraryShortNameByIndex(unsigned Index, StringRef &Res);
+
   // TODO: Would be useful to have an iterator based version
   // of the load command interface too.
 
@@ -198,6 +205,9 @@ public:
   bool is64Bit() const;
   void ReadULEB128s(uint64_t Index, SmallVectorImpl<uint64_t> &Out) const;
 
+  static StringRef guessLibraryShortName(StringRef Name, bool &isFramework,
+                                         StringRef &Suffix);
+
   static Triple::ArchType getArch(uint32_t CPUType);
 
   static bool classof(const Binary *v) {
@@ -207,6 +217,10 @@ public:
 private:
   typedef SmallVector<const char*, 1> SectionList;
   SectionList Sections;
+  typedef SmallVector<const char*, 1> LibraryList;
+  LibraryList Libraries;
+  typedef SmallVector<StringRef, 1> LibraryShortName;
+  LibraryShortName LibrariesShortNames;
   const char *SymtabLoadCmd;
   const char *DysymtabLoadCmd;
   const char *DataInCodeLoadCmd;
diff --git a/include/llvm/Object/SymbolicFile.h b/include/llvm/Object/SymbolicFile.h
index 7b90048717..0801f46d56 100644
--- a/include/llvm/Object/SymbolicFile.h
+++ b/include/llvm/Object/SymbolicFile.h
@@ -86,8 +86,8 @@ public:
     SF_Weak = 1U << 2,           // Weak symbol
     SF_Absolute = 1U << 3,       // Absolute symbol
     SF_Common = 1U << 4,         // Symbol has common linkage
-    SF_Indirect = 1U << 5,
-    SF_FormatSpecific = 1U << 5  // Specific to the object file format
+    SF_Indirect = 1U << 5,       // Symbol is an alias to another symbol
+    SF_FormatSpecific = 1U << 6  // Specific to the object file format
                                  // (e.g. section symbols)
   };
 
diff --git a/include/llvm/Support/MachO.h b/include/llvm/Support/MachO.h
index 2a0fc7bfe0..60f7918ae7 100644
--- a/include/llvm/Support/MachO.h
+++ b/include/llvm/Support/MachO.h
@@ -360,11 +360,28 @@ namespace llvm {
     enum {
       // Constant masks for the "n_desc" field in llvm::MachO::nlist and
       // llvm::MachO::nlist_64
+      // The low 3 bits are the for the REFERENCE_TYPE.
+      REFERENCE_TYPE                            = 0x7,
+      REFERENCE_FLAG_UNDEFINED_NON_LAZY         = 0,
+      REFERENCE_FLAG_UNDEFINED_LAZY             = 1,
+      REFERENCE_FLAG_DEFINED                    = 2,
+      REFERENCE_FLAG_PRIVATE_DEFINED            = 3,
+      REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY = 4,
+      REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY     = 5,
+      // Flag bits (some overlap with the library ordinal bits).
       N_ARM_THUMB_DEF   = 0x0008u,
+      REFERENCED_DYNAMICALLY = 0x0010u,
       N_NO_DEAD_STRIP   = 0x0020u,
       N_WEAK_REF        = 0x0040u,
       N_WEAK_DEF        = 0x0080u,
-      N_SYMBOL_RESOLVER = 0x0100u
+      N_SYMBOL_RESOLVER = 0x0100u,
+      N_ALT_ENTRY       = 0x0200u,
+      // For undefined symbols coming from libraries, see GET_LIBRARY_ORDINAL()
+      // as these are in the top 8 bits.
+      SELF_LIBRARY_ORDINAL   = 0x0,
+      MAX_LIBRARY_ORDINAL    = 0xfd,
+      DYNAMIC_LOOKUP_ORDINAL = 0xfe,
+      EXECUTABLE_ORDINAL     = 0xff 
     };
 
     enum StabType {
diff --git a/lib/Object/MachOObjectFile.cpp b/lib/Object/MachOObjectFile.cpp
index 6dca9750c1..1fb0c13407 100644
--- a/lib/Object/MachOObjectFile.cpp
+++ b/lib/Object/MachOObjectFile.cpp
@@ -223,6 +223,16 @@ void SwapStruct(MachO::version_min_command&C) {
 }
 
 template<>
+void SwapStruct(MachO::dylib_command&C) {
+  SwapValue(C.cmd);
+  SwapValue(C.cmdsize);
+  SwapValue(C.dylib.name);
+  SwapValue(C.dylib.timestamp);
+  SwapValue(C.dylib.current_version);
+  SwapValue(C.dylib.compatibility_version);
+}
+
+template<>
 void SwapStruct(MachO::data_in_code_entry &C) {
   SwapValue(C.offset);
   SwapValue(C.length);
@@ -443,6 +453,12 @@ MachOObjectFile::MachOObjectFile(MemoryBuffer *Object, bool IsLittleEndian,
         const char *Sec = getSectionPtr(this, Load, J);
         Sections.push_back(Sec);
       }
+    } else if (Load.C.cmd == MachO::LC_LOAD_DYLIB ||
+               Load.C.cmd == MachO::LC_LOAD_WEAK_DYLIB ||
+               Load.C.cmd == MachO::LC_LAZY_LOAD_DYLIB ||
+               Load.C.cmd == MachO::LC_REEXPORT_DYLIB ||
+               Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
+      Libraries.push_back(Load.Ptr);
     }
 
     if (I == LoadCommandCount - 1)
@@ -468,6 +484,30 @@ error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
   return object_error::success;
 }
 
+// getIndirectName() returns the name of the alias'ed symbol who's string table
+// index is in the n_value field.
+error_code MachOObjectFile::getIndirectName(DataRefImpl Symb,
+                                            StringRef &Res) const {
+  StringRef StringTable = getStringTableData();
+  uint64_t NValue;
+  if (is64Bit()) {
+    MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
+    NValue = Entry.n_value;
+    if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
+      return object_error::parse_failed;
+  } else {
+    MachO::nlist Entry = getSymbolTableEntry(Symb);
+    NValue = Entry.n_value;
+    if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
+      return object_error::parse_failed;
+  }
+  if (NValue >= StringTable.size())
+    return object_error::parse_failed;
+  const char *Start = &StringTable.data()[NValue];
+  Res = StringRef(Start);
+  return object_error::success;
+}
+
 error_code MachOObjectFile::getSymbolAddress(DataRefImpl Symb,
                                              uint64_t &Res) const {
   if (is64Bit()) {
@@ -1180,6 +1220,189 @@ error_code MachOObjectFile::getLibraryPath(DataRefImpl LibData,
   report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
 }
 
+//
+// guessLibraryShortName() is passed a name of a dynamic library and returns a
+// guess on what the short name is.  Then name is returned as a substring of the
+// StringRef Name passed in.  The name of the dynamic library is recognized as
+// a framework if it has one of the two following forms:
+//      Foo.framework/Versions/A/Foo
+//      Foo.framework/Foo
+// Where A and Foo can be any string.  And may contain a trailing suffix
+// starting with an underbar.  If the Name is recognized as a framework then
+// isFramework is set to true else it is set to false.  If the Name has a
+// suffix then Suffix is set to the substring in Name that contains the suffix
+// else it is set to a NULL StringRef.
+//
+// The Name of the dynamic library is recognized as a library name if it has
+// one of the two following forms:
+//      libFoo.A.dylib
+//      libFoo.dylib
+// The library may have a suffix trailing the name Foo of the form:
+//      libFoo_profile.A.dylib
+//      libFoo_profile.dylib
+//
+// The Name of the dynamic library is also recognized as a library name if it
+// has the following form:
+//      Foo.qtx
+//
+// If the Name of the dynamic library is none of the forms above then a NULL
+// StringRef is returned.
+//
+StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
+                                                 bool &isFramework,
+                                                 StringRef &Suffix) {
+  StringRef Foo, F, DotFramework, V, Dylib, Lib, Dot, Qtx;
+  size_t a, b, c, d, Idx;
+
+  isFramework = false;
+  Suffix = StringRef();
+
+  // Pull off the last component and make Foo point to it
+  a = Name.rfind('/');
+  if (a == Name.npos || a == 0)
+    goto guess_library;
+  Foo = Name.slice(a+1, Name.npos);
+
+  // Look for a suffix starting with a '_'
+  Idx = Foo.rfind('_');
+  if (Idx != Foo.npos && Foo.size() >= 2) {
+    Suffix = Foo.slice(Idx, Foo.npos);
+    Foo = Foo.slice(0, Idx);
+  }
+
+  // First look for the form Foo.framework/Foo
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    Idx = 0;
+  else
+    Idx = b+1;
+  F = Name.slice(Idx, Idx + Foo.size());
+  DotFramework = Name.slice(Idx + Foo.size(),
+                            Idx + Foo.size() + sizeof(".framework/")-1);
+  if (F == Foo && DotFramework == ".framework/") {
+    isFramework = true;
+    return Foo;
+  }
+
+  // Next look for the form Foo.framework/Versions/A/Foo
+  if (b == Name.npos)
+    goto guess_library;
+  c =  Name.rfind('/', b);
+  if (c == Name.npos || c == 0)
+    goto guess_library;
+  V = Name.slice(c+1, Name.npos);
+  if (!V.startswith("Versions/"))
+    goto guess_library;
+  d =  Name.rfind('/', c);
+  if (d == Name.npos)
+    Idx = 0;
+  else
+    Idx = d+1;
+  F = Name.slice(Idx, Idx + Foo.size());
+  DotFramework = Name.slice(Idx + Foo.size(),
+                            Idx + Foo.size() + sizeof(".framework/")-1);
+  if (F == Foo && DotFramework == ".framework/") {
+    isFramework = true;
+    return Foo;
+  }
+
+guess_library:
+  // pull off the suffix after the "." and make a point to it
+  a = Name.rfind('.');
+  if (a == Name.npos || a == 0)
+    return StringRef();
+  Dylib = Name.slice(a, Name.npos);
+  if (Dylib != ".dylib")
+    goto guess_qtx;
+
+  // First pull off the version letter for the form Foo.A.dylib if any.
+  if (a >= 3) {
+    Dot = Name.slice(a-2, a-1);
+    if (Dot == ".")
+      a = a - 2;
+  }
+
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    b = 0;
+  else
+    b = b+1;
+  // ignore any suffix after an underbar like Foo_profile.A.dylib
+  Idx = Name.find('_', b);
+  if (Idx != Name.npos && Idx != b) {
+    Lib = Name.slice(b, Idx);
+    Suffix = Name.slice(Idx, a);
+  }
+  else
+    Lib = Name.slice(b, a);
+  // There are incorrect library names of the form:
+  // libATS.A_profile.dylib so check for these.
+  if (Lib.size() >= 3) {
+    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    if (Dot == ".")
+      Lib = Lib.slice(0, Lib.size()-2);
+  }
+  return Lib;
+
+guess_qtx:
+  Qtx = Name.slice(a, Name.npos);
+  if (Qtx != ".qtx")
+    return StringRef();
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    Lib = Name.slice(0, a);
+  else
+    Lib = Name.slice(b+1, a);
+  // There are library names of the form: QT.A.qtx so check for these.
+  if (Lib.size() >= 3) {
+    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    if (Dot == ".")
+      Lib = Lib.slice(0, Lib.size()-2);
+  }
+  return Lib;
+}
+
+// getLibraryShortNameByIndex() is used to get the short name of the library
+// for an undefined symbol in a linked Mach-O binary that was linked with the
+// normal two-level namespace default (that is MH_TWOLEVEL in the header).
+// It is passed the index (0 - based) of the library as translated from
+// GET_LIBRARY_ORDINAL (1 - based).
+error_code MachOObjectFile::getLibraryShortNameByIndex(unsigned Index,
+                                                       StringRef &Res) {
+  if (Index >= Libraries.size())
+    return object_error::parse_failed;
+
+  MachO::dylib_command D =
+    getStruct<MachO::dylib_command>(this, Libraries[Index]);
+  if (D.dylib.name >= D.cmdsize)
+    return object_error::parse_failed;
+
+  // If the cache of LibrariesShortNames is not built up do that first for
+  // all the Libraries.
+  if (LibrariesShortNames.size() == 0) {
+    for (unsigned i = 0; i < Libraries.size(); i++) {
+      MachO::dylib_command D =
+        getStruct<MachO::dylib_command>(this, Libraries[i]);
+      if (D.dylib.name >= D.cmdsize) {
+        LibrariesShortNames.push_back(StringRef());
+        continue;
+      }
+      char *P = (char *)(Libraries[i]) + D.dylib.name;
+      StringRef Name = StringRef(P);
+      StringRef Suffix;
+      bool isFramework;
+      StringRef shortName = guessLibraryShortName(Name, isFramework, Suffix);
+      if (shortName == StringRef())
+        LibrariesShortNames.push_back(Name);
+      else
+        LibrariesShortNames.push_back(shortName);
+    }
+  }
+
+  Res = LibrariesShortNames[Index];
+  return object_error::success;
+}
+
 basic_symbol_iterator MachOObjectFile::symbol_begin_impl() const {
   return getSymbolByIndex(0);
 }
diff --git a/test/Object/Inputs/darwin-m-test1.mach0-armv7 b/test/Object/Inputs/darwin-m-test1.mach0-armv7
new file mode 100644
index 0000000000..2ce3a18cfa
--- /dev/null
+++ b/test/Object/Inputs/darwin-m-test1.mach0-armv7
diff --git a/test/Object/Inputs/darwin-m-test2.macho-i386 b/test/Object/Inputs/darwin-m-test2.macho-i386
new file mode 100644
index 0000000000..dc0e86525f
--- /dev/null
+++ b/test/Object/Inputs/darwin-m-test2.macho-i386
diff --git a/test/Object/Inputs/darwin-m-test3.macho-x86-64 b/test/Object/Inputs/darwin-m-test3.macho-x86-64
new file mode 100755
index 0000000000..18960c4f6a
--- /dev/null
+++ b/test/Object/Inputs/darwin-m-test3.macho-x86-64
diff --git a/test/Object/nm-darwin-m.test b/test/Object/nm-darwin-m.test
new file mode 100644
index 0000000000..6c718128aa
--- /dev/null
+++ b/test/Object/nm-darwin-m.test
@@ -0,0 +1,53 @@
+RUN: llvm-nm -format darwin %p/Inputs/darwin-m-test1.mach0-armv7 \
+RUN:         | FileCheck %s -check-prefix test1
+RUN: llvm-nm -format darwin %p/Inputs/darwin-m-test2.macho-i386 \
+RUN:         | FileCheck %s -check-prefix test2
+RUN: llvm-nm -format darwin %p/Inputs/darwin-m-test3.macho-x86-64 \
+RUN:         | FileCheck %s -check-prefix test3
+
+# This is testing that the various bits in the n_desc feild are correct
+test1: 00000001 (absolute) non-external _a
+test1: 00000008 (common) (alignment 2^2) external _c
+test1: 0000000a (__DATA,__data) non-external [no dead strip] _d
+test1: 00000004 (__TEXT,__text) non-external [alt entry] _e
+test1: 00000000 (__TEXT,__text) non-external [symbol resolver] _r
+test1: 00000008 (__TEXT,__text) non-external [Thumb] _t
+
+# This is testing that an N_INDR symbol gets its alias name, the "(for ...)"
+test2:          (undefined) external __i
+test2:          (indirect) external _i (for __i)
+
+# This is testing is using darwin-m-test3.macho-x86-64 that is linked with
+# dylibs that have the follow set of -install_names:
+#	Foo.framework/Foo 
+#	/System/Library/Frameworks/FooPath.framework/FooPath 
+#	FooSuffix.framework/FooSuffix_debug
+#	/System/Library/Frameworks/FooPathSuffix.framework/FooPathSuffix_profile
+#	FooVers.framework/Versions/A/FooVers
+#	/System/Library/Frameworks/FooPathVers.framework/Versions/B/FooPathVers
+#	libx.dylib
+#	libxSuffix_profile.dylib
+#	/usr/local/lib/libxPathSuffix_debug.dylib
+#	libATS.A_profile.dylib
+#	/usr/lib/libPathATS.A_profile.dylib
+#	QT.A.qtx
+#	/lib/QTPath.qtx
+#	/usr/lib/libSystem.B.dylib
+# to test that MachOObjectFile::guessLibraryShortName() is correctly parsing 
+# them into their short names.
+test3: 0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
+test3:                  (undefined) external _atsPathVersSuffix (from libPathATS)
+test3:                  (undefined) external _atsVersSuffix (from libATS)
+test3:                  (undefined) external _foo (from Foo)
+test3:                  (undefined) external _fooPath (from FooPath)
+test3:                  (undefined) external _fooPathSuffix (from FooPathSuffix)
+test3:                  (undefined) external _fooPathVers (from FooPathVers)
+test3:                  (undefined) external _fooSuffix (from FooSuffix)
+test3:                  (undefined) external _fooVers (from FooVers)
+test3: 0000000100000e60 (__TEXT,__text) external _main
+test3:                  (undefined) external _qt (from QT)
+test3:                  (undefined) external _qtPath (from QTPath)
+test3:                  (undefined) external _x (from libx)
+test3:                  (undefined) external _xPathSuffix (from libxPathSuffix)
+test3:                  (undefined) external _xSuffix (from libxSuffix)
+test3:                  (undefined) external dyld_stub_binder (from libSystem)
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 476b49486a..0fd43532ed 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -47,11 +47,12 @@ using namespace llvm;
 using namespace object;
 
 namespace {
-enum OutputFormatTy { bsd, sysv, posix };
+enum OutputFormatTy { bsd, sysv, posix, darwin };
 cl::opt<OutputFormatTy> OutputFormat(
     "format", cl::desc("Specify output format"),
     cl::values(clEnumVal(bsd, "BSD format"), clEnumVal(sysv, "System V format"),
-               clEnumVal(posix, "POSIX.2 format"), clEnumValEnd),
+               clEnumVal(posix, "POSIX.2 format"),
+               clEnumVal(darwin, "Darwin -m format"), clEnumValEnd),
     cl::init(bsd));
 cl::alias OutputFormat2("f", cl::desc("Alias for --format"),
                         cl::aliasopt(OutputFormat));
@@ -145,6 +146,7 @@ struct NMSymbol {
   uint64_t Size;
   char TypeChar;
   StringRef Name;
+  DataRefImpl Symb;
 };
 }
 
@@ -204,6 +206,169 @@ static StringRef CurrentFilename;
 typedef std::vector<NMSymbol> SymbolListT;
 static SymbolListT SymbolList;
 
+// darwinPrintSymbol() is used to print a symbol from a Mach-O file when the
+// the OutputFormat is darwin.  It produces the same output as darwin's nm(1) -m
+// output.
+static void darwinPrintSymbol(MachOObjectFile *MachO, SymbolListT::iterator I,
+                              char *SymbolAddrStr, const char *printBlanks) {
+  MachO::mach_header H;
+  MachO::mach_header_64 H_64;
+  uint32_t Filetype, Flags;
+  MachO::nlist_64 STE_64;
+  MachO::nlist STE;
+  uint8_t NType;
+  uint16_t NDesc;
+  uint64_t NValue;
+  if (MachO->is64Bit()) {
+    H_64 = MachO->MachOObjectFile::getHeader64();
+    Filetype = H_64.filetype;
+    Flags = H_64.flags;
+    STE_64 = MachO->getSymbol64TableEntry(I->Symb);
+    NType = STE_64.n_type;
+    NDesc = STE_64.n_desc;
+    NValue = STE_64.n_value;
+  } else {
+    H = MachO->MachOObjectFile::getHeader();
+    Filetype = H.filetype;
+    Flags = H.flags;
+    STE = MachO->getSymbolTableEntry(I->Symb);
+    NType = STE.n_type;
+    NDesc = STE.n_desc;
+    NValue = STE.n_value;
+  }
+
+  if (PrintAddress) {
+    if ((NType & MachO::N_TYPE) == MachO::N_INDR)
+      strcpy(SymbolAddrStr, printBlanks);
+    outs() << SymbolAddrStr << ' ';
+  }
+
+  switch (NType & MachO::N_TYPE) {
+  case MachO::N_UNDF:
+    if (NValue != 0) {
+      outs() << "(common) ";
+      if (MachO::GET_COMM_ALIGN(NDesc) != 0)
+        outs() << "(alignment 2^" <<
+                   (int)MachO::GET_COMM_ALIGN(NDesc) << ") ";
+    } else {
+      if ((NType & MachO::N_TYPE) == MachO::N_PBUD)
+        outs() << "(prebound ";
+      else
+        outs() << "(";
+      if ((NDesc & MachO::REFERENCE_TYPE) ==
+          MachO::REFERENCE_FLAG_UNDEFINED_LAZY)
+        outs() << "undefined [lazy bound]) ";
+      else if ((NDesc & MachO::REFERENCE_TYPE) ==
+               MachO::REFERENCE_FLAG_UNDEFINED_LAZY)
+        outs() << "undefined [private lazy bound]) ";
+      else if ((NDesc & MachO::REFERENCE_TYPE) ==
+               MachO::REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY)
+        outs() << "undefined [private]) ";
+      else
+        outs() << "undefined) ";
+    }
+    break;
+  case MachO::N_ABS:
+    outs() << "(absolute) ";
+    break;
+  case MachO::N_INDR:
+    outs() << "(indirect) ";
+    break;
+  case MachO::N_SECT: {
+    section_iterator Sec = MachO->section_end();
+    MachO->getSymbolSection(I->Symb, Sec);
+    DataRefImpl Ref = Sec->getRawDataRefImpl();
+    StringRef SectionName;
+    MachO->getSectionName(Ref, SectionName);
+    StringRef SegmentName = MachO->getSectionFinalSegmentName(Ref);
+    outs() << "(" << SegmentName << "," << SectionName << ") ";
+    break;
+  }
+  default:
+    outs() << "(?) ";
+    break;
+  }
+
+  if (NType & MachO::N_EXT) {
+    if (NDesc & MachO::REFERENCED_DYNAMICALLY)
+      outs() << "[referenced dynamically] ";
+    if (NType & MachO::N_PEXT) {
+      if ((NDesc & MachO::N_WEAK_DEF) == MachO::N_WEAK_DEF)
+        outs() <<  "weak private external ";
+      else
+        outs() <<  "private external ";
+    } else {
+      if ((NDesc & MachO::N_WEAK_REF) == MachO::N_WEAK_REF ||
+          (NDesc & MachO::N_WEAK_DEF) == MachO::N_WEAK_DEF){
+        if ((NDesc & (MachO::N_WEAK_REF | MachO::N_WEAK_DEF)) ==
+            (MachO::N_WEAK_REF | MachO::N_WEAK_DEF))
+          outs() << "weak external automatically hidden ";
+        else
+          outs() << "weak external ";
+      }
+      else
+        outs() << "external ";
+    }
+  } else {
+    if (NType & MachO::N_PEXT)
+      outs() << "non-external (was a private external) ";
+    else
+      outs() << "non-external ";
+  }
+
+  if (Filetype == MachO::MH_OBJECT &&
+      (NDesc & MachO::N_NO_DEAD_STRIP) == MachO::N_NO_DEAD_STRIP)
+    outs() << "[no dead strip] ";
+
+  if (Filetype == MachO::MH_OBJECT &&
+      ((NType & MachO::N_TYPE) != MachO::N_UNDF) &&
+      (NDesc & MachO::N_SYMBOL_RESOLVER) == MachO::N_SYMBOL_RESOLVER)
+    outs() << "[symbol resolver] ";
+
+  if (Filetype == MachO::MH_OBJECT &&
+      ((NType & MachO::N_TYPE) != MachO::N_UNDF) &&
+      (NDesc & MachO::N_ALT_ENTRY) == MachO::N_ALT_ENTRY)
+    outs() << "[alt entry] ";
+
+  if ((NDesc & MachO::N_ARM_THUMB_DEF) == MachO::N_ARM_THUMB_DEF)
+    outs() << "[Thumb] ";
+
+  if ((NType & MachO::N_TYPE) == MachO::N_INDR) {
+    outs() << I->Name << " (for ";
+    StringRef IndirectName;
+    if (MachO->getIndirectName(I->Symb, IndirectName))
+      outs() << "?)";
+    else
+      outs() << IndirectName << ")";
+  }
+  else
+    outs() << I->Name;
+
+  if ((Flags & MachO::MH_TWOLEVEL) == MachO::MH_TWOLEVEL &&
+      (((NType & MachO::N_TYPE) == MachO::N_UNDF &&
+        NValue == 0) ||
+       (NType & MachO::N_TYPE) == MachO::N_PBUD)) {
+    uint32_t LibraryOrdinal = MachO::GET_LIBRARY_ORDINAL(NDesc);
+    if (LibraryOrdinal != 0) {
+      if (LibraryOrdinal == MachO::EXECUTABLE_ORDINAL)
+        outs() << " (from executable)";
+      else if (LibraryOrdinal == MachO::DYNAMIC_LOOKUP_ORDINAL)
+        outs() << " (dynamically looked up)";
+      else {
+        StringRef LibraryName;
+        if (MachO->getLibraryShortNameByIndex(LibraryOrdinal - 1,
+                                              LibraryName))
+          outs() << " (from bad library ordinal " <<
+                 LibraryOrdinal << ")";
+        else
+          outs() << " (from " << LibraryName << ")";
+      }
+    }
+  }
+
+  outs() << "\n";
+}
+
 static void sortAndPrintSymbolList(SymbolicFile *Obj) {
   if (!NoSort) {
     if (NumericSort)
@@ -256,10 +421,16 @@ static void sortAndPrintSymbolList(SymbolicFile *Obj) {
     if (I->Size != UnknownAddressOrSize)
       format(printFormat, I->Size).print(SymbolSizeStr, sizeof(SymbolSizeStr));
 
-    if (OutputFormat == posix) {
+    // If OutputFormat is darwin and we have a MachOObjectFile print as darwin's
+    // nm(1) -m output, else if OutputFormat is darwin and not a Mach-O object
+    // fall back to OutputFormat bsd (see below).
+    MachOObjectFile *MachO = dyn_cast<MachOObjectFile>(Obj);
+    if (OutputFormat == darwin && MachO) {
+      darwinPrintSymbol(MachO, I, SymbolAddrStr, printBlanks);
+    } else if (OutputFormat == posix) {
       outs() << I->Name << " " << I->TypeChar << " " << SymbolAddrStr
              << SymbolSizeStr << "\n";
-    } else if (OutputFormat == bsd) {
+    } else if (OutputFormat == bsd || (OutputFormat == darwin && !MachO)) {
       if (PrintAddress)
         outs() << SymbolAddrStr << ' ';
       if (PrintSize) {
@@ -529,6 +700,7 @@ static void dumpSymbolNamesFromObject(SymbolicFile *Obj) {
     if (error(I->printName(OS)))
       break;
     OS << '\0';
+    S.Symb = I->getRawDataRefImpl();
     SymbolList.push_back(S);
   }