Index: tools/llvm-readobj/MachODumper.cpp
===================================================================
--- tools/llvm-readobj/MachODumper.cpp
+++ tools/llvm-readobj/MachODumper.cpp
@@ -39,6 +39,9 @@
   void printUnwindInfo() override;
 
 private:
+  template<class MachHeader>
+  void printFileHeaders(const MachHeader &Header);
+
   void printSymbol(const SymbolRef &Symbol);
 
   void printRelocation(const RelocationRef &Reloc);
@@ -68,6 +71,40 @@
 
 } // namespace llvm
 
+static const EnumEntry<uint32_t> MachOMagics[] = {
+  { "Magic",    MachO::MH_MAGIC    },
+  { "Cigam",    MachO::MH_CIGAM    },
+  { "Magic64",    MachO::MH_MAGIC_64 },
+  { "Cigam64",    MachO::MH_CIGAM_64 },
+  { "FatMagic",   MachO::FAT_MAGIC   },
+  { "FatCigam",   MachO::FAT_CIGAM   },
+};
+
+static const EnumEntry<uint32_t> MachOHeaderFileTypes[] = {
+  { "Relocatable",          MachO::MH_OBJECT      },
+  { "Executable",           MachO::MH_EXECUTE     },
+  { "FixedVMLibrary",       MachO::MH_FVMLIB      },
+  { "Core",                 MachO::MH_CORE        },
+  { "PreloadedExecutable",  MachO::MH_PRELOAD     },
+  { "DynamicLibrary",       MachO::MH_DYLIB       },
+  { "DynamicLinker",        MachO::MH_DYLINKER    },
+  { "Bundle",               MachO::MH_BUNDLE      },
+  { "DynamicLibraryStub",   MachO::MH_DYLIB_STUB  },
+  { "DWARFSymbol",          MachO::MH_DSYM        },
+  { "KextBundle",           MachO::MH_KEXT_BUNDLE },
+};
+
+static const EnumEntry<uint32_t> MachOHeaderCpuTypes[] = {
+  { "Any"       , static_cast<uint32_t>(MachO::CPU_TYPE_ANY) },
+  { "I386"      , MachO::CPU_TYPE_I386      },
+  { "X86-64"    , MachO::CPU_TYPE_X86_64    },
+  { "Mc98000"   , MachO::CPU_TYPE_MC98000   },
+  { "Arm"       , MachO::CPU_TYPE_ARM       },
+  { "Arm64"     , MachO::CPU_TYPE_ARM64     },
+  { "Sparc"     , MachO::CPU_TYPE_SPARC     },
+  { "PowerPC"   , MachO::CPU_TYPE_POWERPC   },
+  { "PowerPC64" , MachO::CPU_TYPE_POWERPC64 },
+};
 
 static const EnumEntry<unsigned> MachOSectionTypes[] = {
   { "Regular"                        , 0x00 },
@@ -205,7 +242,24 @@
 }
 
 void MachODumper::printFileHeaders() {
-  W.startLine() << "FileHeaders not implemented.\n";
+  if (!Obj->is64Bit()) {
+    printFileHeaders(Obj->getHeader());
+  } else {
+    printFileHeaders(Obj->getHeader64());
+  }
+}
+
+template<class MachHeader>
+void MachODumper::printFileHeaders(const MachHeader &Header) {
+  DictScope H(W, "MachHeader");
+  W.printEnum("Magic", Header.magic, makeArrayRef(MachOMagics));
+  W.printEnum("CpuType", Header.cputype, makeArrayRef(MachOHeaderCpuTypes));
+  // TODO: implement CPUSubTypeX86, CPUSubTypeARM and etc
+  W.printNumber("CpuSubtype", Header.cpusubtype);
+  W.printEnum("FileType", Header.filetype, makeArrayRef(MachOHeaderFileTypes));
+  W.printNumber("NumOfCommands", Header.ncmds);
+  W.printNumber("SizeOfCommands", Header.sizeofcmds);
+  W.printHex("Flags", Header.flags);
 }
 
 void MachODumper::printSections() {