Index: llvm/include/llvm/BinaryFormat/Magic.h
===================================================================
--- llvm/include/llvm/BinaryFormat/Magic.h
+++ llvm/include/llvm/BinaryFormat/Magic.h
@@ -45,7 +45,8 @@
     coff_import_library, ///< COFF import library
     pecoff_executable,   ///< PECOFF executable file
     windows_resource,    ///< Windows compiled resource file (.res)
-    wasm_object          ///< WebAssembly Object file
+    wasm_object,         ///< WebAssembly Object file
+    tapi_file,           ///< Text-based Dynamic Library Stub file
   };
 
   bool is_object() const { return V != unknown; }
Index: llvm/lib/BinaryFormat/Magic.cpp
===================================================================
--- llvm/lib/BinaryFormat/Magic.cpp
+++ llvm/lib/BinaryFormat/Magic.cpp
@@ -196,6 +196,10 @@
       return file_magic::coff_object;
     break;
 
+  case 0x2d: // Tapi File '-'
+    if (startswith(Magic, "---\narchs:") || startswith(Magic, "--- !tapi"))
+      return file_magic::tapi_file;
+
   default:
     break;
   }
Index: llvm/lib/Object/Binary.cpp
===================================================================
--- llvm/lib/Object/Binary.cpp
+++ llvm/lib/Object/Binary.cpp
@@ -77,6 +77,7 @@
     return WindowsResource::createWindowsResource(Buffer);
   case file_magic::unknown:
   case file_magic::coff_cl_gl_object:
+  case file_magic::tapi_file:
     // Unrecognized object file format.
     return errorCodeToError(object_error::invalid_file_type);
   }
Index: llvm/lib/Object/ObjectFile.cpp
===================================================================
--- llvm/lib/Object/ObjectFile.cpp
+++ llvm/lib/Object/ObjectFile.cpp
@@ -92,6 +92,7 @@
   case file_magic::archive:
   case file_magic::macho_universal_binary:
   case file_magic::windows_resource:
+  case file_magic::tapi_file:
     return errorCodeToError(object_error::invalid_file_type);
   case file_magic::elf:
   case file_magic::elf_relocatable:
Index: llvm/lib/Object/SymbolicFile.cpp
===================================================================
--- llvm/lib/Object/SymbolicFile.cpp
+++ llvm/lib/Object/SymbolicFile.cpp
@@ -52,6 +52,7 @@
   case file_magic::coff_cl_gl_object:
   case file_magic::macho_universal_binary:
   case file_magic::windows_resource:
+  case file_magic::tapi_file:
     return errorCodeToError(object_error::invalid_file_type);
   case file_magic::elf:
   case file_magic::elf_executable:
Index: llvm/unittests/BinaryFormat/TestFileMagic.cpp
===================================================================
--- llvm/unittests/BinaryFormat/TestFileMagic.cpp
+++ llvm/unittests/BinaryFormat/TestFileMagic.cpp
@@ -81,6 +81,8 @@
 const char macho_dynamically_linked_shared_lib_stub[] =
     "\xfe\xed\xfa\xce........\x00\x00\x00\x09............";
 const char ms_dos_stub_broken[] = "\x4d\x5a\x20\x20";
+const char tapi_file[] = "--- !tapi-tbd-v1\n";
+const char tapi_file_tbd_v1[] = "---\narchs: [";
 
 TEST_F(MagicTest, Magic) {
   struct type {
@@ -112,6 +114,9 @@
       DEFINE(windows_resource),
       {"ms_dos_stub_broken", ms_dos_stub_broken, sizeof(ms_dos_stub_broken),
        file_magic::unknown},
+      DEFINE(tapi_file),
+      {"tapi_file_tbd_v1", tapi_file_tbd_v1, sizeof(tapi_file_tbd_v1),
+       file_magic::tapi_file},
 #undef DEFINE
   };