diff --git a/lib/Lex/HeaderMap.cpp b/lib/Lex/HeaderMap.cpp
index 4010d61..5d9b218 100644
--- a/lib/Lex/HeaderMap.cpp
+++ b/lib/Lex/HeaderMap.cpp
@@ -75,13 +75,14 @@
 /// map.  If it doesn't look like a HeaderMap, it gives up and returns null.
 /// If it looks like a HeaderMap but is obviously corrupted, it puts a reason
 /// into the string error argument and returns null.
-const HeaderMap *HeaderMap::Create(const FileEntry *FE) {
+const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM,
+                                   const FileSystemOptions &FSOpts) {
   // If the file is too small to be a header map, ignore it.
   unsigned FileSize = FE->getSize();
   if (FileSize <= sizeof(HMapHeader)) return 0;
 
   llvm::OwningPtr<const llvm::MemoryBuffer> FileBuffer(
-    llvm::MemoryBuffer::getFile(FE->getName(), 0, FE->getSize()));
+    FM.getBufferForFile(FE, FSOpts));
   if (FileBuffer == 0) return 0;  // Unreadable file?
   const char *FileStart = FileBuffer->getBufferStart();
 
@@ -200,7 +201,8 @@
 /// LookupFile - Check to see if the specified relative filename is located in
 /// this HeaderMap.  If so, open it and return its FileEntry.
 const FileEntry *HeaderMap::LookupFile(llvm::StringRef Filename,
-                                       FileManager &FM) const {
+                                       FileManager &FM,
+                                const FileSystemOptions &FileSystemOpts) const {
   const HMapHeader &Hdr = getHeader();
   unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets);
 
@@ -223,6 +225,6 @@
     llvm::SmallString<1024> DestPath;
     DestPath += getString(B.Prefix);
     DestPath += getString(B.Suffix);
-    return FM.getFile(DestPath.begin(), DestPath.end());
+    return FM.getFile(DestPath.begin(), DestPath.end(), FileSystemOpts);
   }
 }
diff --git a/lib/Lex/HeaderSearch.cpp b/lib/Lex/HeaderSearch.cpp
index 4554aba..5a11652 100644
--- a/lib/Lex/HeaderSearch.cpp
+++ b/lib/Lex/HeaderSearch.cpp
@@ -32,7 +32,8 @@
   return ControllingMacro;
 }
 
-HeaderSearch::HeaderSearch(FileManager &FM) : FileMgr(FM), FrameworkMap(64) {
+HeaderSearch::HeaderSearch(FileManager &FM, const FileSystemOptions &FSOpts)
+    : FileMgr(FM), FileSystemOpts(FSOpts), FrameworkMap(64) {
   SystemDirIdx = 0;
   NoCurDirSearch = false;
 
@@ -83,7 +84,7 @@
         return HeaderMaps[i].second;
   }
 
-  if (const HeaderMap *HM = HeaderMap::Create(FE)) {
+  if (const HeaderMap *HM = HeaderMap::Create(FE, FileMgr, FileSystemOpts)) {
     HeaderMaps.push_back(std::make_pair(FE, HM));
     return HM;
   }
@@ -118,14 +119,16 @@
     TmpDir += getDir()->getName();
     TmpDir.push_back('/');
     TmpDir.append(Filename.begin(), Filename.end());
-    return HS.getFileMgr().getFile(TmpDir.begin(), TmpDir.end());
+    return HS.getFileMgr().getFile(TmpDir.begin(), TmpDir.end(),
+                                   HS.getFileSystemOpts());
   }
 
   if (isFramework())
     return DoFrameworkLookup(Filename, HS);
 
   assert(isHeaderMap() && "Unknown directory lookup");
-  return getHeaderMap()->LookupFile(Filename, HS.getFileMgr());
+  return getHeaderMap()->LookupFile(Filename, HS.getFileMgr(),
+                                    HS.getFileSystemOpts());
 }
 
 
@@ -134,6 +137,7 @@
 const FileEntry *DirectoryLookup::DoFrameworkLookup(llvm::StringRef Filename,
                                                     HeaderSearch &HS) const {
   FileManager &FileMgr = HS.getFileMgr();
+  const FileSystemOptions &FileSystemOpts = HS.getFileSystemOpts();
 
   // Framework names must have a '/' in the filename.
   size_t SlashPos = Filename.find('/');
@@ -184,7 +188,8 @@
   FrameworkName += "Headers/";
   FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
   if (const FileEntry *FE = FileMgr.getFile(FrameworkName.begin(),
-                                            FrameworkName.end())) {
+                                            FrameworkName.end(),
+                                            FileSystemOpts)) {
     return FE;
   }
 
@@ -192,7 +197,8 @@
   const char *Private = "Private";
   FrameworkName.insert(FrameworkName.begin()+OrigSize, Private,
                        Private+strlen(Private));
-  return FileMgr.getFile(FrameworkName.begin(), FrameworkName.end());
+  return FileMgr.getFile(FrameworkName.begin(), FrameworkName.end(),
+                         FileSystemOpts);
 }
 
 
@@ -219,7 +225,7 @@
     if (FromDir) return 0;
 
     // Otherwise, just return the file.
-    return FileMgr.getFile(Filename);
+    return FileMgr.getFile(Filename, FileSystemOpts);
   }
 
   // Step #0, unless disabled, check to see if the file is in the #includer's
@@ -234,7 +240,7 @@
     TmpDir += CurFileEnt->getDir()->getName();
     TmpDir.push_back('/');
     TmpDir.append(Filename.begin(), Filename.end());
-    if (const FileEntry *FE = FileMgr.getFile(TmpDir.str())) {
+    if (const FileEntry *FE = FileMgr.getFile(TmpDir.str(), FileSystemOpts)) {
       // Leave CurDir unset.
       // This file is a system header or C++ unfriendly if the old file is.
       //
@@ -344,7 +350,8 @@
 
     // If the framework dir doesn't exist, we fail.
     const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.begin(),
-                                                     FrameworkName.end());
+                                                     FrameworkName.end(),
+                                                     FileSystemOpts);
     if (Dir == 0) return 0;
 
     // Otherwise, if it does, remember that this is the right direntry for this
@@ -359,13 +366,14 @@
   HeadersFilename += "Headers/";
   HeadersFilename.append(Filename.begin()+SlashPos+1, Filename.end());
   if (!(FE = FileMgr.getFile(HeadersFilename.begin(),
-                             HeadersFilename.end()))) {
+                             HeadersFilename.end(), FileSystemOpts))) {
 
     // Check ".../Frameworks/HIToolbox.framework/PrivateHeaders/HIToolbox.h"
     HeadersFilename = FrameworkName;
     HeadersFilename += "PrivateHeaders/";
     HeadersFilename.append(Filename.begin()+SlashPos+1, Filename.end());
-    if (!(FE = FileMgr.getFile(HeadersFilename.begin(), HeadersFilename.end())))
+    if (!(FE = FileMgr.getFile(HeadersFilename.begin(), HeadersFilename.end(),
+                               FileSystemOpts)))
       return 0;
   }
 
diff --git a/lib/Lex/PTHLexer.cpp b/lib/Lex/PTHLexer.cpp
index 63b4823..3d52159 100644
--- a/lib/Lex/PTHLexer.cpp
+++ b/lib/Lex/PTHLexer.cpp
@@ -434,10 +434,12 @@
   Diags.Report(Diags.getCustomDiagID(Diagnostic::Error, Msg));
 }
 
-PTHManager* PTHManager::Create(const std::string& file, Diagnostic &Diags) {
+PTHManager* PTHManager::Create(const std::string& file, FileManager &FileMgr,
+                               const FileSystemOptions &FSOpts,
+                               Diagnostic &Diags) {
   // Memory map the PTH file.
   llvm::OwningPtr<llvm::MemoryBuffer>
-  File(llvm::MemoryBuffer::getFile(file.c_str()));
+  File(FileMgr.getBufferForFile(file, FSOpts));
 
   if (!File) {
     Diags.Report(diag::err_invalid_pth_file) << file;
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 1be22df..ff18c3f 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -53,7 +53,8 @@
                            IdentifierInfoLookup* IILookup,
                            bool OwnsHeaders)
   : Diags(&diags), Features(opts), Target(target),FileMgr(Headers.getFileMgr()),
-    SourceMgr(SM), HeaderInfo(Headers), ExternalSource(0),
+    FileSystemOpts(Headers.getFileSystemOpts()), SourceMgr(SM),
+    HeaderInfo(Headers), ExternalSource(0),
     Identifiers(opts, IILookup), BuiltinInfo(Target), CodeComplete(0),
     CodeCompletionFile(0), SkipMainFilePreamble(0, true), CurPPLexer(0), 
     CurDirLookup(0), Callbacks(0), MacroArgCache(0), Record(0), MIChainHead(0),