Path: Recognize COFF import library file magic.

Summary: Make identify_magic to recognize COFF import file.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2165

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194852 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Path.cpp b/lib/Support/Path.cpp
index dfa18aa..c869b30 100644
--- a/lib/Support/Path.cpp
+++ b/lib/Support/Path.cpp
@@ -848,6 +848,10 @@
     return file_magic::unknown;
   switch ((unsigned char)Magic[0]) {
     case 0x00: {
+      // COFF short import library file
+      if (Magic[1] == (char)0x00 && Magic[2] == (char)0xff &&
+          Magic[3] == (char)0xff)
+        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) &&