Add MachO MH_FILESET support to objdump

[pete]

Summary

On macOS, the kernel and kexts are linked in to a file known as a kernel collection. This is a new kind of mach-o, with a filetype of MH_FILESET.

Prior to this PR, llvm-objdump would say "not an object file" if you tried to read from an MH_FILESET. Now it understands enough to print the mach header.

[beanz]

Looks reasonable and straight forward to me.

[JDevlieghere]

LGTM

llvm/include/llvm/BinaryFormat/MachO.h

enum HeaderFileType {
   MH_FVMLIB = 0x3u,
   MH_CORE = 0x4u,
   MH_PRELOAD = 0x5u,
   MH_DYLIB = 0x6u,
   MH_DYLINKER = 0x7u,
   MH_BUNDLE = 0x8u,
   MH_DYLIB_STUB = 0x9u,
   MH_DSYM = 0xAu,
-  MH_KEXT_BUNDLE = 0xBu
+  MH_KEXT_BUNDLE = 0xBu,
+  MH_FILESET = 0xCu
 };
 
 enum {
   // Constant bits for the "flags" field in llvm::MachO::mach_header and
   // llvm::MachO::mach_header_64
   MH_NOUNDEFS = 0x00000001u,
   MH_INCRLINK = 0x00000002u,
   MH_DYLDLINK = 0x00000004u,

llvm/include/llvm/BinaryFormat/Magic.h

enum Impl {
     macho_preload_executable,                 ///< Mach-O Preloaded Executable
     macho_dynamically_linked_shared_lib,      ///< Mach-O dynlinked shared lib
     macho_dynamic_linker,                     ///< The Mach-O dynamic linker
     macho_bundle,                             ///< Mach-O Bundle file
     macho_dynamically_linked_shared_lib_stub, ///< Mach-O Shared lib stub
     macho_dsym_companion,                     ///< Mach-O dSYM companion file
     macho_kext_bundle,                        ///< Mach-O kext bundle file
     macho_universal_binary,                   ///< Mach-O universal binary
+    macho_file_set,                           ///< Mach-O file set binary
     minidump,                                 ///< Windows minidump file
     coff_cl_gl_object,   ///< Microsoft cl.exe's intermediate code file
     coff_object,         ///< COFF object file
     coff_import_library, ///< COFF import library
     pecoff_executable,   ///< PECOFF executable file
     windows_resource,    ///< Windows compiled resource file (.res)
     xcoff_object_32,     ///< 32-bit XCOFF object file
     xcoff_object_64,     ///< 64-bit XCOFF object file

llvm/lib/BinaryFormat/Magic.cpp

case 0xCF: {
     case 8:
       return file_magic::macho_bundle;
     case 9:
       return file_magic::macho_dynamically_linked_shared_lib_stub;
     case 10:
       return file_magic::macho_dsym_companion;
     case 11:
       return file_magic::macho_kext_bundle;
+    case 12:
+      return file_magic::macho_file_set;
     }
     break;
   }
   case 0xF0: // PowerPC Windows
   case 0x83: // Alpha 32-bit
   case 0x84: // Alpha 64-bit
   case 0x66: // MPS R4000 Windows
   case 0x50: // mc68K

llvm/lib/Object/Binary.cpp

Expected<std::unique_ptr<Binary>> object::createBinary(MemoryBufferRef Buffer,
   case file_magic::macho_core:
   case file_magic::macho_preload_executable:
   case file_magic::macho_dynamically_linked_shared_lib:
   case file_magic::macho_dynamic_linker:
   case file_magic::macho_bundle:
   case file_magic::macho_dynamically_linked_shared_lib_stub:
   case file_magic::macho_dsym_companion:
   case file_magic::macho_kext_bundle:
+  case file_magic::macho_file_set:
   case file_magic::coff_object:
   case file_magic::coff_import_library:
   case file_magic::pecoff_executable:
   case file_magic::bitcode:
   case file_magic::xcoff_object_32:
   case file_magic::xcoff_object_64:
   case file_magic::wasm_object:
     return ObjectFile::createSymbolicFile(Buffer, Type, Context, InitContent);

llvm/lib/Object/ObjectFile.cpp

ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type,
   case file_magic::macho_core:
   case file_magic::macho_preload_executable:
   case file_magic::macho_dynamically_linked_shared_lib:
   case file_magic::macho_dynamic_linker:
   case file_magic::macho_bundle:
   case file_magic::macho_dynamically_linked_shared_lib_stub:
   case file_magic::macho_dsym_companion:
   case file_magic::macho_kext_bundle:
+  case file_magic::macho_file_set:
     return createMachOObjectFile(Object);
   case file_magic::coff_object:
   case file_magic::coff_import_library:
   case file_magic::pecoff_executable:
     return createCOFFObjectFile(Object);
   case file_magic::xcoff_object_32:
     return createXCOFFObjectFile(Object, Binary::ID_XCOFF32);
   case file_magic::xcoff_object_64:

llvm/lib/Object/SymbolicFile.cpp

SymbolicFile::createSymbolicFile(MemoryBufferRef Object, file_magic Type,
   case file_magic::macho_core:
   case file_magic::macho_preload_executable:
   case file_magic::macho_dynamically_linked_shared_lib:
   case file_magic::macho_dynamic_linker:
   case file_magic::macho_bundle:
   case file_magic::macho_dynamically_linked_shared_lib_stub:
   case file_magic::macho_dsym_companion:
   case file_magic::macho_kext_bundle:
+  case file_magic::macho_file_set:
   case file_magic::pecoff_executable:
   case file_magic::xcoff_object_32:
   case file_magic::xcoff_object_64:
   case file_magic::wasm_object:
     return ObjectFile::createObjectFile(Object, Type, InitContent);
   case file_magic::coff_import_library:
     return std::unique_ptr<SymbolicFile>(new COFFImportFile(Object));
   case file_magic::elf_relocatable:
bool SymbolicFile::isSymbolicFile(file_magic Type, const LLVMContext *Context) {
   case file_magic::macho_core:
   case file_magic::macho_preload_executable:
   case file_magic::macho_dynamically_linked_shared_lib:
   case file_magic::macho_dynamic_linker:
   case file_magic::macho_bundle:
   case file_magic::macho_dynamically_linked_shared_lib_stub:
   case file_magic::macho_dsym_companion:
   case file_magic::macho_kext_bundle:
+  case file_magic::macho_file_set:
   case file_magic::pecoff_executable:
   case file_magic::xcoff_object_32:
   case file_magic::xcoff_object_64:
   case file_magic::wasm_object:
   case file_magic::coff_import_library:
   case file_magic::elf_relocatable:
   case file_magic::macho_object:
   case file_magic::coff_object:
     return true;
   default:
     return false;
   }
 }

llvm/test/Object/AArch64/filetype-fileset.yaml

+# REQUIRES: host-byteorder-little-endian
+# RUN: yaml2obj %s \
+# RUN:   | llvm-objdump --macho --private-header - 2>&1 \
+# RUN:   | FileCheck %s
+
+# CHECK: magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
+# CHECK-NEXT: MH_MAGIC_64 ARM64 ALL 0x00 FILESET 0 0 0x00000000
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x100000C
+  cpusubtype:      0x0
+  filetype:        0xC
+  ncmds:           0
+  sizeofcmds:      0
+  flags:           0x0
+  reserved:        0x0

llvm/tools/llvm-objdump/MachODump.cpp

case MachO::MH_BUNDLE:
       outs() << "      BUNDLE";
       break;
     case MachO::MH_DSYM:
       outs() << "        DSYM";
       break;
     case MachO::MH_KEXT_BUNDLE:
       outs() << "  KEXTBUNDLE";
       break;
+    case MachO::MH_FILESET:
+      outs() << "     FILESET";
+      break;
     default:
       outs() << format("  %10u", filetype);
       break;
     }
     outs() << format(" %5u", ncmds);
     outs() << format(" %10u", sizeofcmds);
     uint32_t f = flags;
     if (f & MachO::MH_NOUNDEFS) {