diff --git a/include/clang/Basic/FileManager.h b/include/clang/Basic/FileManager.h
index 99fa5fa..255eee3 100644
--- a/include/clang/Basic/FileManager.h
+++ b/include/clang/Basic/FileManager.h
@@ -63,9 +63,9 @@
   time_t ModTime;             // Modification time of file.
   const DirectoryEntry *Dir;  // Directory file lives in.
   unsigned UID;               // A unique (small) ID for the file.
-  dev_t Device;               // ID for the device containing the file.
-  ino_t Inode;                // Inode number for the file.
-  mode_t FileMode;            // The file mode as returned by 'stat'.
+  llvm::sys::fs::UniqueID UniqueID;
+  bool IsNamedPipe;
+  bool InPCH;
 
   /// FD - The file descriptor for the file entry if it is opened and owned
   /// by the FileEntry.  If not, this is set to -1.
@@ -73,10 +73,12 @@
   friend class FileManager;
 
 public:
-  FileEntry(dev_t device, ino_t inode, mode_t m)
-    : Name(0), Device(device), Inode(inode), FileMode(m), FD(-1) {}
+  FileEntry(llvm::sys::fs::UniqueID UniqueID, bool IsNamedPipe, bool InPCH)
+      : Name(0), UniqueID(UniqueID), IsNamedPipe(IsNamedPipe), InPCH(InPCH),
+        FD(-1) {}
   // Add a default constructor for use with llvm::StringMap
-  FileEntry() : Name(0), Device(0), Inode(0), FileMode(0), FD(-1) {}
+  FileEntry()
+      : Name(0), UniqueID(0, 0), IsNamedPipe(false), InPCH(false), FD(-1) {}
 
   FileEntry(const FileEntry &FE) {
     memcpy(this, &FE, sizeof(FE));
@@ -93,23 +95,22 @@
   const char *getName() const { return Name; }
   off_t getSize() const { return Size; }
   unsigned getUID() const { return UID; }
-  ino_t getInode() const { return Inode; }
-  dev_t getDevice() const { return Device; }
+  const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
+  bool isInPCH() const { return InPCH; }
   time_t getModificationTime() const { return ModTime; }
-  mode_t getFileMode() const { return FileMode; }
 
   /// \brief Return the directory the file lives in.
   const DirectoryEntry *getDir() const { return Dir; }
 
-  bool operator<(const FileEntry &RHS) const {
-    return Device < RHS.Device || (Device == RHS.Device && Inode < RHS.Inode);
-  }
+  bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
 
   /// \brief Check whether the file is a named pipe (and thus can't be opened by
   /// the native FileManager methods).
-  bool isNamedPipe() const;
+  bool isNamedPipe() const { return IsNamedPipe; }
 };
 
+struct FileData;
+
 /// \brief Implements support for file system lookup, file system caching,
 /// and directory search management.
 ///
@@ -170,8 +171,8 @@
   // Caching.
   OwningPtr<FileSystemStatCache> StatCache;
 
-  bool getStatValue(const char *Path, struct stat &StatBuf,
-                    bool isFile, int *FileDescriptor);
+  bool getStatValue(const char *Path, FileData &Data, bool isFile,
+                    int *FileDescriptor);
 
   /// Add all ancestors of the given path (pointing to either a file
   /// or a directory) as virtual directories.
diff --git a/include/clang/Basic/FileSystemStatCache.h b/include/clang/Basic/FileSystemStatCache.h
index ff70373..23d8256 100644
--- a/include/clang/Basic/FileSystemStatCache.h
+++ b/include/clang/Basic/FileSystemStatCache.h
@@ -18,11 +18,21 @@
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/Support/FileSystem.h"
 #include <sys/stat.h>
 #include <sys/types.h>
 
 namespace clang {
 
+struct FileData {
+  uint64_t Size;
+  time_t ModTime;
+  llvm::sys::fs::UniqueID UniqueID;
+  bool IsDirectory;
+  bool IsNamedPipe;
+  bool InPCH;
+};
+
 /// \brief Abstract interface for introducing a FileManager cache for 'stat'
 /// system calls, which is used by precompiled and pretokenized headers to
 /// improve performance.
@@ -49,10 +59,9 @@
   /// success for directories (not files).  On a successful file lookup, the
   /// implementation can optionally fill in FileDescriptor with a valid
   /// descriptor and the client guarantees that it will close it.
-  static bool get(const char *Path, struct stat &StatBuf,
-                  bool isFile, int *FileDescriptor, FileSystemStatCache *Cache);
-  
-  
+  static bool get(const char *Path, FileData &Data, bool isFile,
+                  int *FileDescriptor, FileSystemStatCache *Cache);
+
   /// \brief Sets the next stat call cache in the chain of stat caches.
   /// Takes ownership of the given stat cache.
   void setNextStatCache(FileSystemStatCache *Cache) {
@@ -68,18 +77,18 @@
   FileSystemStatCache *takeNextStatCache() { return NextStatCache.take(); }
   
 protected:
-  virtual LookupResult getStat(const char *Path, struct stat &StatBuf,
-                               bool isFile, int *FileDescriptor) = 0;
+  virtual LookupResult getStat(const char *Path, FileData &Data, bool isFile,
+                               int *FileDescriptor) = 0;
 
-  LookupResult statChained(const char *Path, struct stat &StatBuf,
-                           bool isFile, int *FileDescriptor) {
+  LookupResult statChained(const char *Path, FileData &Data, bool isFile,
+                           int *FileDescriptor) {
     if (FileSystemStatCache *Next = getNextStatCache())
-      return Next->getStat(Path, StatBuf, isFile, FileDescriptor);
-    
+      return Next->getStat(Path, Data, isFile, FileDescriptor);
+
     // If we hit the end of the list of stat caches to try, just compute and
     // return it without a cache.
-    return get(Path, StatBuf,
-               isFile, FileDescriptor, 0) ? CacheMissing : CacheExists;
+    return get(Path, Data, isFile, FileDescriptor, 0) ? CacheMissing
+                                                      : CacheExists;
   }
 };
 
@@ -89,16 +98,16 @@
 class MemorizeStatCalls : public FileSystemStatCache {
 public:
   /// \brief The set of stat() calls that have been seen.
-  llvm::StringMap<struct stat, llvm::BumpPtrAllocator> StatCalls;
-  
-  typedef llvm::StringMap<struct stat, llvm::BumpPtrAllocator>::const_iterator
+  llvm::StringMap<FileData, llvm::BumpPtrAllocator> StatCalls;
+
+  typedef llvm::StringMap<FileData, llvm::BumpPtrAllocator>::const_iterator
   iterator;
-  
+
   iterator begin() const { return StatCalls.begin(); }
   iterator end() const { return StatCalls.end(); }
-  
-  virtual LookupResult getStat(const char *Path, struct stat &StatBuf,
-                               bool isFile, int *FileDescriptor);
+
+  virtual LookupResult getStat(const char *Path, FileData &Data, bool isFile,
+                               int *FileDescriptor);
 };
 
 } // end namespace clang
diff --git a/lib/Basic/FileManager.cpp b/lib/Basic/FileManager.cpp
index 079b7ff..af9b266 100644
--- a/lib/Basic/FileManager.cpp
+++ b/lib/Basic/FileManager.cpp
@@ -63,91 +63,16 @@
   if (FD != -1) ::close(FD);
 }
 
-bool FileEntry::isNamedPipe() const {
-  return S_ISFIFO(FileMode);
-}
-
-//===----------------------------------------------------------------------===//
-// Windows.
-//===----------------------------------------------------------------------===//
-
-#ifdef LLVM_ON_WIN32
-
-namespace {
-  static std::string GetFullPath(const char *relPath) {
-    char *absPathStrPtr = _fullpath(NULL, relPath, 0);
-    assert(absPathStrPtr && "_fullpath() returned NULL!");
-
-    std::string absPath(absPathStrPtr);
-
-    free(absPathStrPtr);
-    return absPath;
-  }
-}
-
-class FileManager::UniqueDirContainer {
-  /// UniqueDirs - Cache from full path to existing directories/files.
-  ///
-  llvm::StringMap<DirectoryEntry> UniqueDirs;
-
-public:
-  /// getDirectory - Return an existing DirectoryEntry with the given
-  /// name if there is already one; otherwise create and return a
-  /// default-constructed DirectoryEntry.
-  DirectoryEntry &getDirectory(const char *Name,
-                               const struct stat & /*StatBuf*/) {
-    std::string FullPath(GetFullPath(Name));
-    return UniqueDirs.GetOrCreateValue(FullPath).getValue();
-  }
-
-  size_t size() const { return UniqueDirs.size(); }
-};
-
-class FileManager::UniqueFileContainer {
-  /// UniqueFiles - Cache from full path to existing directories/files.
-  ///
-  llvm::StringMap<FileEntry, llvm::BumpPtrAllocator> UniqueFiles;
-
-public:
-  /// getFile - Return an existing FileEntry with the given name if
-  /// there is already one; otherwise create and return a
-  /// default-constructed FileEntry.
-  FileEntry &getFile(const char *Name, const struct stat & /*StatBuf*/) {
-    std::string FullPath(GetFullPath(Name));
-
-    // Lowercase string because Windows filesystem is case insensitive.
-    FullPath = StringRef(FullPath).lower();
-    return UniqueFiles.GetOrCreateValue(FullPath).getValue();
-  }
-
-  size_t size() const { return UniqueFiles.size(); }
-
-  void erase(const FileEntry *Entry) {
-    std::string FullPath(GetFullPath(Entry->getName()));
-
-    // Lowercase string because Windows filesystem is case insensitive.
-    FullPath = StringRef(FullPath).lower();
-    UniqueFiles.erase(FullPath);
-  }
-};
-
-//===----------------------------------------------------------------------===//
-// Unix-like Systems.
-//===----------------------------------------------------------------------===//
-
-#else
-
 class FileManager::UniqueDirContainer {
   /// UniqueDirs - Cache from ID's to existing directories/files.
-  std::map<std::pair<dev_t, ino_t>, DirectoryEntry> UniqueDirs;
+  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueDirs;
 
 public:
   /// getDirectory - Return an existing DirectoryEntry with the given
   /// ID's if there is already one; otherwise create and return a
   /// default-constructed DirectoryEntry.
-  DirectoryEntry &getDirectory(const char * /*Name*/,
-                               const struct stat &StatBuf) {
-    return UniqueDirs[std::make_pair(StatBuf.st_dev, StatBuf.st_ino)];
+  DirectoryEntry &getDirectory(const llvm::sys::fs::UniqueID &UniqueID) {
+    return UniqueDirs[UniqueID];
   }
 
   size_t size() const { return UniqueDirs.size(); }
@@ -161,12 +86,10 @@
   /// getFile - Return an existing FileEntry with the given ID's if
   /// there is already one; otherwise create and return a
   /// default-constructed FileEntry.
-  FileEntry &getFile(const char * /*Name*/, const struct stat &StatBuf) {
-    return
-      const_cast<FileEntry&>(
-                    *UniqueFiles.insert(FileEntry(StatBuf.st_dev,
-                                                  StatBuf.st_ino,
-                                                  StatBuf.st_mode)).first);
+  FileEntry &getFile(llvm::sys::fs::UniqueID UniqueID, bool IsNamedPipe,
+                     bool InPCH) {
+    return const_cast<FileEntry &>(
+        *UniqueFiles.insert(FileEntry(UniqueID, IsNamedPipe, InPCH)).first);
   }
 
   size_t size() const { return UniqueFiles.size(); }
@@ -174,8 +97,6 @@
   void erase(const FileEntry *Entry) { UniqueFiles.erase(*Entry); }
 };
 
-#endif
-
 //===----------------------------------------------------------------------===//
 // Common logic.
 //===----------------------------------------------------------------------===//
@@ -323,8 +244,8 @@
   const char *InterndDirName = NamedDirEnt.getKeyData();
 
   // Check to see if the directory exists.
-  struct stat StatBuf;
-  if (getStatValue(InterndDirName, StatBuf, false, 0/*directory lookup*/)) {
+  FileData Data;
+  if (getStatValue(InterndDirName, Data, false, 0 /*directory lookup*/)) {
     // There's no real directory at the given path.
     if (!CacheFailure)
       SeenDirEntries.erase(DirName);
@@ -335,7 +256,8 @@
   // same inode (this occurs on Unix-like systems when one dir is
   // symlinked to another, for example) or the same path (on
   // Windows).
-  DirectoryEntry &UDE = UniqueRealDirs.getDirectory(InterndDirName, StatBuf);
+  DirectoryEntry &UDE =
+      UniqueRealDirs.getDirectory(Data.UniqueID);
 
   NamedDirEnt.setValue(&UDE);
   if (!UDE.getName()) {
@@ -388,8 +310,8 @@
 
   // Nope, there isn't.  Check to see if the file exists.
   int FileDescriptor = -1;
-  struct stat StatBuf;
-  if (getStatValue(InterndFileName, StatBuf, true,
+  FileData Data;
+  if (getStatValue(InterndFileName, Data, true,
                    openFile ? &FileDescriptor : 0)) {
     // There's no real file at the given path.
     if (!CacheFailure)
@@ -405,7 +327,8 @@
 
   // It exists.  See if we have already opened a file with the same inode.
   // This occurs when one dir is symlinked to another, for example.
-  FileEntry &UFE = UniqueRealFiles.getFile(InterndFileName, StatBuf);
+  FileEntry &UFE =
+      UniqueRealFiles.getFile(Data.UniqueID, Data.IsNamedPipe, Data.InPCH);
 
   NamedFileEnt.setValue(&UFE);
   if (UFE.getName()) { // Already have an entry with this inode, return it.
@@ -420,8 +343,8 @@
   // FIXME: Change the name to be a char* that points back to the
   // 'SeenFileEntries' key.
   UFE.Name    = InterndFileName;
-  UFE.Size    = StatBuf.st_size;
-  UFE.ModTime = StatBuf.st_mtime;
+  UFE.Size = Data.Size;
+  UFE.ModTime = Data.ModTime;
   UFE.Dir     = DirInfo;
   UFE.UID     = NextFileUID++;
   UFE.FD      = FileDescriptor;
@@ -458,12 +381,12 @@
          "The directory of a virtual file should already be in the cache.");
 
   // Check to see if the file exists. If so, drop the virtual file
-  struct stat StatBuf;
+  FileData Data;
   const char *InterndFileName = NamedFileEnt.getKeyData();
-  if (getStatValue(InterndFileName, StatBuf, true, 0) == 0) {
-    StatBuf.st_size = Size;
-    StatBuf.st_mtime = ModificationTime;
-    UFE = &UniqueRealFiles.getFile(InterndFileName, StatBuf);
+  if (getStatValue(InterndFileName, Data, true, 0) == 0) {
+    Data.Size = Size;
+    Data.ModTime = ModificationTime;
+    UFE = &UniqueRealFiles.getFile(Data.UniqueID, Data.IsNamedPipe, Data.InPCH);
 
     NamedFileEnt.setValue(UFE);
 
@@ -572,19 +495,19 @@
 /// if the path points to a virtual file or does not exist, or returns
 /// false if it's an existent real file.  If FileDescriptor is NULL,
 /// do directory look-up instead of file look-up.
-bool FileManager::getStatValue(const char *Path, struct stat &StatBuf,
-                               bool isFile, int *FileDescriptor) {
+bool FileManager::getStatValue(const char *Path, FileData &Data, bool isFile,
+                               int *FileDescriptor) {
   // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be
   // absolute!
   if (FileSystemOpts.WorkingDir.empty())
-    return FileSystemStatCache::get(Path, StatBuf, isFile, FileDescriptor,
+    return FileSystemStatCache::get(Path, Data, isFile, FileDescriptor,
                                     StatCache.get());
 
   SmallString<128> FilePath(Path);
   FixupRelativePath(FilePath);
 
-  return FileSystemStatCache::get(FilePath.c_str(), StatBuf,
-                                  isFile, FileDescriptor, StatCache.get());
+  return FileSystemStatCache::get(FilePath.c_str(), Data, isFile,
+                                  FileDescriptor, StatCache.get());
 }
 
 bool FileManager::getNoncachedStatValue(StringRef Path,
diff --git a/lib/Basic/FileSystemStatCache.cpp b/lib/Basic/FileSystemStatCache.cpp
index b71259e..7a01bff 100644
--- a/lib/Basic/FileSystemStatCache.cpp
+++ b/lib/Basic/FileSystemStatCache.cpp
@@ -30,6 +30,16 @@
 
 void FileSystemStatCache::anchor() { }
 
+static void copyStatusToFileData(const llvm::sys::fs::file_status &Status,
+                                 FileData &Data) {
+  Data.Size = Status.getSize();
+  Data.ModTime = Status.getLastModificationTime().toEpochTime();
+  Data.UniqueID = Status.getUniqueID();
+  Data.IsDirectory = is_directory(Status);
+  Data.IsNamedPipe = Status.type() == llvm::sys::fs::file_type::fifo_file;
+  Data.InPCH = false;
+}
+
 /// FileSystemStatCache::get - Get the 'stat' information for the specified
 /// path, using the cache to accelerate it if possible.  This returns true if
 /// the path does not exist or false if it exists.
@@ -39,19 +49,24 @@
 /// success for directories (not files).  On a successful file lookup, the
 /// implementation can optionally fill in FileDescriptor with a valid
 /// descriptor and the client guarantees that it will close it.
-bool FileSystemStatCache::get(const char *Path, struct stat &StatBuf,
-                              bool isFile, int *FileDescriptor,
-                              FileSystemStatCache *Cache) {
+bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
+                              int *FileDescriptor, FileSystemStatCache *Cache) {
   LookupResult R;
   bool isForDir = !isFile;
 
   // If we have a cache, use it to resolve the stat query.
   if (Cache)
-    R = Cache->getStat(Path, StatBuf, isFile, FileDescriptor);
+    R = Cache->getStat(Path, Data, isFile, FileDescriptor);
   else if (isForDir || !FileDescriptor) {
     // If this is a directory or a file descriptor is not needed and we have
     // no cache, just go to the file system.
-    R = ::stat(Path, &StatBuf) != 0 ? CacheMissing : CacheExists;
+    llvm::sys::fs::file_status Status;
+    if (llvm::sys::fs::status(Path, Status)) {
+      R = CacheMissing;
+    } else {
+      R = CacheExists;
+      copyStatusToFileData(Status, Data);
+    }
   } else {
     // Otherwise, we have to go to the filesystem.  We can always just use
     // 'stat' here, but (for files) the client is asking whether the file exists
@@ -69,9 +84,11 @@
       // Otherwise, the open succeeded.  Do an fstat to get the information
       // about the file.  We'll end up returning the open file descriptor to the
       // client to do what they please with it.
-      if (::fstat(*FileDescriptor, &StatBuf) == 0)
+      llvm::sys::fs::file_status Status;
+      if (!llvm::sys::fs::status(*FileDescriptor, Status)) {
         R = CacheExists;
-      else {
+        copyStatusToFileData(Status, Data);
+      } else {
         // fstat rarely fails.  If it does, claim the initial open didn't
         // succeed.
         R = CacheMissing;
@@ -86,7 +103,7 @@
   
   // If the path exists, make sure that its "directoryness" matches the clients
   // demands.
-  if (S_ISDIR(StatBuf.st_mode) != isForDir) {
+  if (Data.IsDirectory != isForDir) {
     // If not, close the file if opened.
     if (FileDescriptor && *FileDescriptor != -1) {
       ::close(*FileDescriptor);
@@ -99,12 +116,11 @@
   return false;
 }
 
-
 MemorizeStatCalls::LookupResult
-MemorizeStatCalls::getStat(const char *Path, struct stat &StatBuf,
-                           bool isFile, int *FileDescriptor) {
-  LookupResult Result = statChained(Path, StatBuf, isFile, FileDescriptor);
-  
+MemorizeStatCalls::getStat(const char *Path, FileData &Data, bool isFile,
+                           int *FileDescriptor) {
+  LookupResult Result = statChained(Path, Data, isFile, FileDescriptor);
+
   // Do not cache failed stats, it is easy to construct common inconsistent
   // situations if we do, and they are not important for PCH performance (which
   // currently only needs the stats to construct the initial FileManager
@@ -113,8 +129,8 @@
     return Result;
   
   // Cache file 'stat' results and directories with absolutely paths.
-  if (!S_ISDIR(StatBuf.st_mode) || llvm::sys::path::is_absolute(Path))
-    StatCalls[Path] = StatBuf;
-  
+  if (!Data.IsDirectory || llvm::sys::path::is_absolute(Path))
+    StatCalls[Path] = Data;
+
   return Result;
 }
diff --git a/lib/Frontend/CacheTokens.cpp b/lib/Frontend/CacheTokens.cpp
index 3f80a16..0c30b04 100644
--- a/lib/Frontend/CacheTokens.cpp
+++ b/lib/Frontend/CacheTokens.cpp
@@ -58,16 +58,16 @@
 class PTHEntryKeyVariant {
   union { const FileEntry* FE; const char* Path; };
   enum { IsFE = 0x1, IsDE = 0x2, IsNoExist = 0x0 } Kind;
-  struct stat *StatBuf;
+  FileData *Data;
+
 public:
-  PTHEntryKeyVariant(const FileEntry *fe)
-    : FE(fe), Kind(IsFE), StatBuf(0) {}
+  PTHEntryKeyVariant(const FileEntry *fe) : FE(fe), Kind(IsFE), Data(0) {}
 
-  PTHEntryKeyVariant(struct stat* statbuf, const char* path)
-    : Path(path), Kind(IsDE), StatBuf(new struct stat(*statbuf)) {}
+  PTHEntryKeyVariant(FileData *Data, const char *path)
+      : Path(path), Kind(IsDE), Data(new FileData(*Data)) {}
 
-  explicit PTHEntryKeyVariant(const char* path)
-    : Path(path), Kind(IsNoExist), StatBuf(0) {}
+  explicit PTHEntryKeyVariant(const char *path)
+      : Path(path), Kind(IsNoExist), Data(0) {}
 
   bool isFile() const { return Kind == IsFE; }
 
@@ -79,22 +79,21 @@
 
   void EmitData(raw_ostream& Out) {
     switch (Kind) {
-    case IsFE:
+    case IsFE: {
       // Emit stat information.
-      ::Emit32(Out, FE->getInode());
-      ::Emit32(Out, FE->getDevice());
-      ::Emit16(Out, FE->getFileMode());
+      llvm::sys::fs::UniqueID UID = FE->getUniqueID();
+      ::Emit64(Out, UID.getFile());
+      ::Emit64(Out, UID.getDevice());
       ::Emit64(Out, FE->getModificationTime());
       ::Emit64(Out, FE->getSize());
-      break;
+    } break;
     case IsDE:
       // Emit stat information.
-      ::Emit32(Out, (uint32_t) StatBuf->st_ino);
-      ::Emit32(Out, (uint32_t) StatBuf->st_dev);
-      ::Emit16(Out, (uint16_t) StatBuf->st_mode);
-      ::Emit64(Out, (uint64_t) StatBuf->st_mtime);
-      ::Emit64(Out, (uint64_t) StatBuf->st_size);
-      delete StatBuf;
+      ::Emit64(Out, Data->UniqueID.getFile());
+      ::Emit64(Out, Data->UniqueID.getDevice());
+      ::Emit64(Out, Data->ModTime);
+      ::Emit64(Out, Data->Size);
+      delete Data;
       break;
     default:
       break;
@@ -516,18 +515,18 @@
   StatListener(PTHMap &pm) : PM(pm) {}
   ~StatListener() {}
 
-  LookupResult getStat(const char *Path, struct stat &StatBuf,
-                       bool isFile, int *FileDescriptor) {
-    LookupResult Result = statChained(Path, StatBuf, isFile, FileDescriptor);
+  LookupResult getStat(const char *Path, FileData &Data, bool isFile,
+                       int *FileDescriptor) {
+    LookupResult Result = statChained(Path, Data, isFile, FileDescriptor);
 
     if (Result == CacheMissing) // Failed 'stat'.
       PM.insert(PTHEntryKeyVariant(Path), PTHEntry());
-    else if (S_ISDIR(StatBuf.st_mode)) {
+    else if (Data.IsDirectory) {
       // Only cache directories with absolute paths.
       if (llvm::sys::path::is_relative(Path))
         return Result;
 
-      PM.insert(PTHEntryKeyVariant(&StatBuf, Path), PTHEntry());
+      PM.insert(PTHEntryKeyVariant(&Data, Path), PTHEntry());
     }
 
     return Result;
diff --git a/lib/Frontend/TextDiagnostic.cpp b/lib/Frontend/TextDiagnostic.cpp
index 2da66d3..691ca34 100644
--- a/lib/Frontend/TextDiagnostic.cpp
+++ b/lib/Frontend/TextDiagnostic.cpp
@@ -778,11 +778,8 @@
       const FileEntry* FE = SM.getFileEntryForID(FID);
       if (FE && FE->getName()) {
         OS << FE->getName();
-        if (FE->getDevice() == 0 && FE->getInode() == 0
-            && FE->getFileMode() == 0) {
-          // in PCH is a guess, but a good one:
+        if (FE->isInPCH())
           OS << " (in PCH)";
-        }
         OS << ": ";
       }
     }
diff --git a/lib/Lex/PTHLexer.cpp b/lib/Lex/PTHLexer.cpp
index e8f43f7..32da92a 100644
--- a/lib/Lex/PTHLexer.cpp
+++ b/lib/Lex/PTHLexer.cpp
@@ -619,18 +619,18 @@
 namespace {
 class PTHStatData {
 public:
-  const bool hasStat;
-  const ino_t ino;
-  const dev_t dev;
-  const mode_t mode;
-  const time_t mtime;
-  const off_t size;
+  const bool HasData;
+  uint64_t Size;
+  time_t ModTime;
+  llvm::sys::fs::UniqueID UniqueID;
+  bool IsDirectory;
 
-  PTHStatData(ino_t i, dev_t d, mode_t mo, time_t m, off_t s)
-  : hasStat(true), ino(i), dev(d), mode(mo), mtime(m), size(s) {}
+  PTHStatData(uint64_t Size, time_t ModTime, llvm::sys::fs::UniqueID UniqueID,
+              bool IsDirectory)
+      : HasData(true), Size(Size), ModTime(ModTime), UniqueID(UniqueID),
+        IsDirectory(IsDirectory) {}
 
-  PTHStatData()
-    : hasStat(false), ino(0), dev(0), mode(0), mtime(0), size(0) {}
+  PTHStatData() : HasData(false) {}
 };
 
 class PTHStatLookupTrait : public PTHFileLookupCommonTrait {
@@ -653,12 +653,18 @@
                             unsigned) {
 
     if (k.first /* File or Directory */) {
-      if (k.first == 0x1 /* File */) d += 4 * 2; // Skip the first 2 words.
-      ino_t ino = (ino_t) ReadUnalignedLE32(d);
-      dev_t dev = (dev_t) ReadUnalignedLE32(d);
-      mode_t mode = (mode_t) ReadUnalignedLE16(d);
-      time_t mtime = (time_t) ReadUnalignedLE64(d);
-      return data_type(ino, dev, mode, mtime, (off_t) ReadUnalignedLE64(d));
+      bool IsDirectory = true;
+      if (k.first == 0x1 /* File */) {
+        IsDirectory = false;
+        d += 4 * 2; // Skip the first 2 words.
+      }
+
+      uint64_t File = ReadUnalignedLE64(d);
+      uint64_t Device = ReadUnalignedLE64(d);
+      llvm::sys::fs::UniqueID UniqueID(File, Device);
+      time_t ModTime = ReadUnalignedLE64(d);
+      uint64_t Size = ReadUnalignedLE64(d);
+      return data_type(Size, ModTime, UniqueID, IsDirectory);
     }
 
     // Negative stat.  Don't read anything.
@@ -677,25 +683,27 @@
 
   ~PTHStatCache() {}
 
-  LookupResult getStat(const char *Path, struct stat &StatBuf,
-                       bool isFile, int *FileDescriptor) {
+  LookupResult getStat(const char *Path, FileData &Data, bool isFile,
+                       int *FileDescriptor) {
     // Do the lookup for the file's data in the PTH file.
     CacheTy::iterator I = Cache.find(Path);
 
     // If we don't get a hit in the PTH file just forward to 'stat'.
     if (I == Cache.end())
-      return statChained(Path, StatBuf, isFile, FileDescriptor);
+      return statChained(Path, Data, isFile, FileDescriptor);
 
-    const PTHStatData &Data = *I;
+    const PTHStatData &D = *I;
 
-    if (!Data.hasStat)
+    if (!D.HasData)
       return CacheMissing;
 
-    StatBuf.st_ino = Data.ino;
-    StatBuf.st_dev = Data.dev;
-    StatBuf.st_mtime = Data.mtime;
-    StatBuf.st_mode = Data.mode;
-    StatBuf.st_size = Data.size;
+    Data.Size = D.Size;
+    Data.ModTime = D.ModTime;
+    Data.UniqueID = D.UniqueID;
+    Data.IsDirectory = D.IsDirectory;
+    Data.IsNamedPipe = false;
+    Data.InPCH = true;
+
     return CacheExists;
   }
 };
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 9f6300a..2007951 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -3057,15 +3057,12 @@
   if (!file || !outID)
     return 1;
 
-#ifdef LLVM_ON_WIN32
-  return 1; // inodes not supported on windows.
-#else
   FileEntry *FEnt = static_cast<FileEntry *>(file);
-  outID->data[0] = FEnt->getDevice();
-  outID->data[1] = FEnt->getInode();
+  const llvm::sys::fs::UniqueID &ID = FEnt->getUniqueID();
+  outID->data[0] = ID.getDevice();
+  outID->data[1] = ID.getFile();
   outID->data[2] = FEnt->getModificationTime();
   return 0;
-#endif
 }
 
 } // end: extern "C"
diff --git a/tools/libclang/Indexing.cpp b/tools/libclang/Indexing.cpp
index 15786ac..e2b898b 100644
--- a/tools/libclang/Indexing.cpp
+++ b/tools/libclang/Indexing.cpp
@@ -88,25 +88,23 @@
 ///   #3 is identified as the location of "#ifdef CAKE"
 ///
 class PPRegion {
-  ino_t ino;
+  llvm::sys::fs::UniqueID UniqueID;
   time_t ModTime;
-  dev_t dev;
   unsigned Offset;
 public:
-  PPRegion() : ino(), ModTime(), dev(), Offset() {}
-  PPRegion(dev_t dev, ino_t ino, unsigned offset, time_t modTime)
-    : ino(ino), ModTime(modTime), dev(dev), Offset(offset) {}
+  PPRegion() : ModTime(), Offset() {}
+  PPRegion(llvm::sys::fs::UniqueID UniqueID, unsigned offset, time_t modTime)
+      : UniqueID(UniqueID), ModTime(modTime), Offset(offset) {}
 
-  ino_t getIno() const { return ino; }
-  dev_t getDev() const { return dev; }
+  const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
   unsigned getOffset() const { return Offset; }
   time_t getModTime() const { return ModTime; }
 
   bool isInvalid() const { return *this == PPRegion(); }
 
   friend bool operator==(const PPRegion &lhs, const PPRegion &rhs) {
-    return lhs.dev == rhs.dev && lhs.ino == rhs.ino &&
-        lhs.Offset == rhs.Offset && lhs.ModTime == rhs.ModTime;
+    return lhs.UniqueID == rhs.UniqueID && lhs.Offset == rhs.Offset &&
+           lhs.ModTime == rhs.ModTime;
   }
 };
 
@@ -122,16 +120,17 @@
   template <>
   struct DenseMapInfo<PPRegion> {
     static inline PPRegion getEmptyKey() {
-      return PPRegion(0, 0, unsigned(-1), 0);
+      return PPRegion(llvm::sys::fs::UniqueID(0, 0), unsigned(-1), 0);
     }
     static inline PPRegion getTombstoneKey() {
-      return PPRegion(0, 0, unsigned(-2), 0);
+      return PPRegion(llvm::sys::fs::UniqueID(0, 0), unsigned(-2), 0);
     }
 
     static unsigned getHashValue(const PPRegion &S) {
       llvm::FoldingSetNodeID ID;
-      ID.AddInteger(S.getIno());
-      ID.AddInteger(S.getDev());
+      const llvm::sys::fs::UniqueID &UniqueID = S.getUniqueID();
+      ID.AddInteger(UniqueID.getFile());
+      ID.AddInteger(UniqueID.getDevice());
       ID.AddInteger(S.getOffset());
       ID.AddInteger(S.getModTime());
       return ID.ComputeHash();
@@ -208,9 +207,10 @@
   PPRegion getRegion(SourceLocation Loc, FileID FID, const FileEntry *FE) {
     SourceLocation RegionLoc = PPRec.findConditionalDirectiveRegionLoc(Loc);
     if (RegionLoc.isInvalid()) {
-      if (isParsedOnceInclude(FE))
-        return PPRegion(FE->getDevice(), FE->getInode(), 0,
-                        FE->getModificationTime());
+      if (isParsedOnceInclude(FE)) {
+        const llvm::sys::fs::UniqueID &ID = FE->getUniqueID();
+        return PPRegion(ID, 0, FE->getModificationTime());
+      }
       return PPRegion();
     }
 
@@ -221,14 +221,15 @@
     llvm::tie(RegionFID, RegionOffset) = SM.getDecomposedLoc(RegionLoc);
 
     if (RegionFID != FID) {
-      if (isParsedOnceInclude(FE))
-        return PPRegion(FE->getDevice(), FE->getInode(), 0,
-                        FE->getModificationTime());
+      if (isParsedOnceInclude(FE)) {
+        const llvm::sys::fs::UniqueID &ID = FE->getUniqueID();
+        return PPRegion(ID, 0, FE->getModificationTime());
+      }
       return PPRegion();
     }
 
-    return PPRegion(FE->getDevice(), FE->getInode(), RegionOffset,
-                    FE->getModificationTime());
+    const llvm::sys::fs::UniqueID &ID = FE->getUniqueID();
+    return PPRegion(ID, RegionOffset, FE->getModificationTime());
   }
 
   bool isParsedOnceInclude(const FileEntry *FE) {
diff --git a/unittests/Basic/FileManagerTest.cpp b/unittests/Basic/FileManagerTest.cpp
index d86c96f..f8ce50d 100644
--- a/unittests/Basic/FileManagerTest.cpp
+++ b/unittests/Basic/FileManagerTest.cpp
@@ -24,18 +24,15 @@
 private:
   // Maps a file/directory path to its desired stat result.  Anything
   // not in this map is considered to not exist in the file system.
-  llvm::StringMap<struct stat, llvm::BumpPtrAllocator> StatCalls;
+  llvm::StringMap<FileData, llvm::BumpPtrAllocator> StatCalls;
 
   void InjectFileOrDirectory(const char *Path, ino_t INode, bool IsFile) {
-    struct stat statBuf;
-    memset(&statBuf, 0, sizeof(statBuf));
-    statBuf.st_dev = 1;
-#ifndef _WIN32  // struct stat has no st_ino field on Windows.
-    statBuf.st_ino = INode;
-#endif
-    statBuf.st_mode = IsFile ? (0777 | S_IFREG)  // a regular file
-        : (0777 | S_IFDIR);  // a directory
-    StatCalls[Path] = statBuf;
+    FileData Data;
+    memset(&Data, 0, sizeof(FileData));
+    llvm::sys::fs::UniqueID ID(1, INode);
+    Data.UniqueID = ID;
+    Data.IsDirectory = !IsFile;
+    StatCalls[Path] = Data;
   }
 
 public:
@@ -50,10 +47,10 @@
   }
 
   // Implement FileSystemStatCache::getStat().
-  virtual LookupResult getStat(const char *Path, struct stat &StatBuf,
-                               bool isFile, int *FileDescriptor) {
+  virtual LookupResult getStat(const char *Path, FileData &Data, bool isFile,
+                               int *FileDescriptor) {
     if (StatCalls.count(Path) != 0) {
-      StatBuf = StatCalls[Path];
+      Data = StatCalls[Path];
       return CacheExists;
     }