Teach identify_file_magic to identify PDB files.

llvm-svn: 326924

Author: Zachary Turner

llvm/include/llvm/BinaryFormat/Magic.h

@@ -45,7 +45,8 @@ struct file_magic {
     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
+    pdb,                 ///< Windows PDB debug info file
   };
 
   bool is_object() const { return V != unknown; }

llvm/lib/BinaryFormat/Magic.cpp

@@ -181,14 +181,16 @@ file_magic llvm::identify_magic(StringRef Magic) {
       return file_magic::coff_object;
     break;
 
-  case 'M': // Possible MS-DOS stub on Windows PE file
+  case 'M': // Possible MS-DOS stub on Windows PE file or MSF/PDB file.
     if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) {
       uint32_t off = read32le(Magic.data() + 0x3c);
       // PE/COFF file, either EXE or DLL.
       if (Magic.substr(off).startswith(
               StringRef(COFF::PEMagic, sizeof(COFF::PEMagic))))
         return file_magic::pecoff_executable;
     }
+    if (Magic.startswith("Microsoft C/C++ MSF 7.00\r\n"))
+      return file_magic::pdb;
     break;
 
   case 0x64: // x86-64 or ARM64 Windows.

llvm/unittests/BinaryFormat/TestFileMagic.cpp

@@ -81,6 +81,8 @@ const char windows_resource[] =
 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 pdb[] = "Microsoft C/C++ MSF 7.00\r\n\x1a"
+                   "DS\x00\x00\x00";
 
 TEST_F(MagicTest, Magic) {
   struct type {
@@ -110,6 +112,7 @@ TEST_F(MagicTest, Magic) {
       DEFINE(macho_dsym_companion),
       DEFINE(macho_kext_bundle),
       DEFINE(windows_resource),
+      DEFINE(pdb),
       {"ms_dos_stub_broken", ms_dos_stub_broken, sizeof(ms_dos_stub_broken),
        file_magic::unknown},
 #undef DEFINE