Include st_dev to make the result of getUniqueID actually unique.

This will let us use getUniqueID instead of st_dev directly on clang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187378 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/FileSystem.h

@@ -125,8 +125,19 @@ inline perms operator~(perms x) {
   return static_cast<perms>(~static_cast<unsigned short>(x));
 }
 
+class UniqueID {
+  uint64_t A;
+  uint64_t B;
+
+public:
+  UniqueID() {}
+  UniqueID(uint64_t A, uint64_t B) : A(A), B(B) {}
+  bool operator==(const UniqueID &Other) const {
+    return A == Other.A && B == Other.B;
+  }
+  bool operator!=(const UniqueID &Other) const { return !(*this == Other); }
+};
 
- 
 /// file_status - Represents the result of a call to stat and friends. It has
 ///               a platform specific member to store the result.
 class file_status
@@ -148,7 +159,6 @@ class file_status
   uint32_t FileIndexLow;
   #endif
   friend bool equivalent(file_status A, file_status B);
-  friend error_code getUniqueID(const Twine Path, uint64_t &Result);
   file_type Type;
   perms Perms;
 public:
@@ -176,6 +186,7 @@ public:
   file_type type() const { return Type; }
   perms permissions() const { return Perms; }
   TimeValue getLastModificationTime() const;
+  UniqueID getUniqueID();
 
   #if defined(LLVM_ON_UNIX)
   uint32_t getUser() const { return fs_st_uid; }
@@ -664,7 +675,7 @@ file_magic identify_magic(StringRef magic);
 ///          platform specific error_code.
 error_code identify_magic(const Twine &path, file_magic &result);
 
-error_code getUniqueID(const Twine Path, uint64_t &Result);
+error_code getUniqueID(const Twine Path, UniqueID &Result);
 
 /// This class represents a memory mapped file. It is based on
 /// boost::iostreams::mapped_file.