Support: improve identify_magic to recognize COFF bigobj

[ruiu]

Summary

identify_magic recognized a COFF bigobj as an import library file.
This patch fixes that.

[• rafael]

LGTM

[Eugene.Zelenko]

Committed in r217627.

lib/Support/Path.cpp

 }
 
 /// @brief Identify the magic in magic.
 file_magic identify_magic(StringRef Magic) {
   if (Magic.size() < 4)
     return file_magic::unknown;
   switch ((unsigned char)Magic[0]) {
     case 0x00: {
-      // COFF short import library file
+      // COFF bigobj or short import library file
       if (Magic[1] == (char)0x00 && Magic[2] == (char)0xff &&
-          Magic[3] == (char)0xff)
+          Magic[3] == (char)0xff) {
+         const char BigobjMagic[] =
+             "\xc7\xa1\xba\xd1\xee\xba\xa9\x4b\xaf\x20\xfa\xf6\x6a\xa4\xdc\xb8";
+         if (Magic.size() >= 28 &&
+             memcmp(Magic.data() + 12, BigobjMagic, sizeof(BigobjMagic)) == 0)
+           return file_magic::coff_object;
          return file_magic::coff_import_library;
+      }
       // Windows resource file
       const char Expected[] = { 0, 0, 0, 0, '\x20', 0, 0, 0, '\xff' };
       if (Magic.size() >= sizeof(Expected) &&
           memcmp(Magic.data(), Expected, sizeof(Expected)) == 0)
         return file_magic::windows_resource;
       // 0x0000 = COFF unknown machine type
       if (Magic[1] == 0)
         return file_magic::coff_object;

unittests/Support/Path.cpp

TEST_F(FileSystemTest, DirectoryIteration) {
   ASSERT_NO_ERROR(fs::remove(Twine(TestDirectory) + "/recursive/z0/za1"));
   ASSERT_NO_ERROR(fs::remove(Twine(TestDirectory) + "/recursive/z0"));
   ASSERT_NO_ERROR(fs::remove(Twine(TestDirectory) + "/recursive"));
 }
 
 const char archive[] = "!<arch>\x0A";
 const char bitcode[] = "\xde\xc0\x17\x0b";
 const char coff_object[] = "\x00\x00......";
+const char coff_bigobj[] = "\x00\x00............"
+    "\xc7\xa1\xba\xd1\xee\xba\xa9\x4b\xaf\x20\xfa\xf6\x6a\xa4\xdc\xb8";
 const char coff_import_library[] = "\x00\x00\xff\xff....";
 const char elf_relocatable[] = { 0x7f, 'E', 'L', 'F', 1, 2, 1, 0, 0,
                                  0,    0,   0,   0,   0, 0, 0, 0, 1 };
 const char macho_universal_binary[] = "\xca\xfe\xba\xbe...\0x00";
 const char macho_object[] = "\xfe\xed\xfa\xce..........\x00\x01";
 const char macho_executable[] = "\xfe\xed\xfa\xce..........\x00\x02";
 const char macho_fixed_virtual_memory_shared_lib[] =
     "\xfe\xed\xfa\xce..........\x00\x03";
struct type {
     size_t magic_str_len;
     fs::file_magic magic;
   } types[] = {
 #define DEFINE(magic)                                           \
     { #magic, magic, sizeof(magic), fs::file_magic::magic }
     DEFINE(archive),
     DEFINE(bitcode),
     DEFINE(coff_object),
+    { "coff_bigobj", coff_bigobj, sizeof(coff_bigobj), fs::file_magic::coff_object },
     DEFINE(coff_import_library),
     DEFINE(elf_relocatable),
     DEFINE(macho_universal_binary),
     DEFINE(macho_object),
     DEFINE(macho_executable),
     DEFINE(macho_fixed_virtual_memory_shared_lib),
     DEFINE(macho_core),
     DEFINE(macho_preload_executable),