Index: tools/llvm-readobj/MachODumper.cpp
===================================================================
--- tools/llvm-readobj/MachODumper.cpp
+++ tools/llvm-readobj/MachODumper.cpp
@@ -205,7 +205,27 @@
 }
 
 void MachODumper::printFileHeaders() {
-  W.startLine() << "FileHeaders not implemented.\n";
+  DictScope H(W, "MachHeader");
+  if (!Obj->is64Bit()) {
+    const MachO::mach_header Header = Obj->getHeader();
+    W.printHex("Magic", Header.magic);
+    W.printNumber("CpuType", Header.cputype);
+    W.printNumber("CpuSubtype", Header.cpusubtype);
+    W.printNumber("FileType", Header.filetype);
+    W.printNumber("NumOfCommands", Header.ncmds);
+    W.printNumber("SizeOfCommands", Header.sizeofcmds);
+    W.printHex("Flags", Header.flags);
+  } else {
+    const MachO::mach_header_64 Header64 = Obj->getHeader64();
+    W.printHex("Magic", Header64.magic);
+    W.printNumber("CpuType", Header64.cputype);
+    W.printNumber("CpuSubtype", Header64.cpusubtype);
+    W.printNumber("FileType", Header64.filetype);
+    W.printNumber("NumOfCommands", Header64.ncmds);
+    W.printNumber("SizeOfCommands", Header64.sizeofcmds);
+    W.printHex("Flags", Header64.flags);
+    W.printHex("Reserved", Header64.reserved);
+  }
 }
 
 void MachODumper::printSections() {