4 files changed, 16 insertions, 7 deletions
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 3fca309102a..8d46a8f4a5d 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -20,6 +20,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
+#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
@@ -37,7 +38,6 @@
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Atomic.h"
 #include "llvm/Support/CrashRecoveryContext.h"
-#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
@@ -1418,7 +1418,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
              REnd = PreprocessorOpts.remapped_file_end();
            !AnyFileChanged && R != REnd;
            ++R) {
-        llvm::sys::fs::file_status Status;
+        vfs::Status Status;
         if (FileMgr->getNoncachedStatValue(R->second, Status)) {
           // If we can't stat the file we're remapping to, assume that something
           // horrible happened.
@@ -1454,7 +1454,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
         }
         
         // The file was not remapped; check whether it has changed on disk.
-        llvm::sys::fs::file_status Status;
+        vfs::Status Status;
         if (FileMgr->getNoncachedStatValue(F->first(), Status)) {
           // If we can't stat the file, assume that something horrible happened.
           AnyFileChanged = true;
diff --git a/clang/lib/Frontend/CacheTokens.cpp b/clang/lib/Frontend/CacheTokens.cpp
index 0c30b049579..5cb364e3f5c 100644
--- a/clang/lib/Frontend/CacheTokens.cpp
+++ b/clang/lib/Frontend/CacheTokens.cpp
@@ -516,8 +516,8 @@ public:
   ~StatListener() {}
 
   LookupResult getStat(const char *Path, FileData &Data, bool isFile,
-                       int *FileDescriptor) {
-    LookupResult Result = statChained(Path, Data, isFile, FileDescriptor);
+                       vfs::File **F, vfs::FileSystem &FS) {
+    LookupResult Result = statChained(Path, Data, isFile, F, FS);
 
     if (Result == CacheMissing) // Failed 'stat'.
       PM.insert(PTHEntryKeyVariant(Path), PTHEntry());
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 61fe26c9222..df0095205c3 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -79,6 +79,10 @@ void CompilerInstance::setTarget(TargetInfo *Value) {
 
 void CompilerInstance::setFileManager(FileManager *Value) {
   FileMgr = Value;
+  if (Value)
+    VirtualFileSystem = Value->getVirtualFileSystem();
+  else
+    VirtualFileSystem.reset();
 }
 
 void CompilerInstance::setSourceManager(SourceManager *Value) {
@@ -197,7 +201,11 @@ CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
 // File Manager
 
 void CompilerInstance::createFileManager() {
-  FileMgr = new FileManager(getFileSystemOpts());
+  if (!hasVirtualFileSystem()) {
+    // TODO: choose the virtual file system based on the CompilerInvocation.
+    setVirtualFileSystem(vfs::getRealFileSystem());
+  }
+  FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
 }
 
 // Source Manager
@@ -867,6 +875,8 @@ static void compileModule(CompilerInstance &ImportingInstance,
                                    ImportingInstance.getDiagnosticClient()),
                              /*ShouldOwnClient=*/true);
 
+  Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
+
   // Note that this module is part of the module build stack, so that we
   // can detect cycles in the module graph.
   Instance.createFileManager(); // FIXME: Adopt file manager from importer?
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 0baf3e5e1fb..72377d84572 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -159,7 +159,6 @@ ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
   return new MultiplexConsumer(Consumers);
 }
 
-
 bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
                                      const FrontendInputFile &Input) {
   assert(!Instance && "Already processing a source file!");