Lift VFS from clang to llvm (NFC)

This patch moves the virtual file system form clang to llvm so it can be
used by more projects.

Concretely the patch:
 - Moves VirtualFileSystem.{h|cpp} from clang/Basic to llvm/Support.
 - Moves the corresponding unit test from clang to llvm.
 - Moves the vfs namespace from clang::vfs to llvm::vfs.
 - Formats the lines affected by this change, mostly this is the result of
   the added llvm namespace.

RFC on the mailing list:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/126657.html

Differential revision: https://reviews.llvm.org/D52783

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@344140 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/FileManager.h

@@ -16,7 +16,7 @@
 #define LLVM_CLANG_BASIC_FILEMANAGER_H
 
 #include "clang/Basic/FileSystemOptions.h"
-#include "clang/Basic/VirtualFileSystem.h"
+#include "clang/Basic/LLVM.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SmallVector.h"
@@ -25,9 +25,10 @@
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <ctime>
-#include <memory>
 #include <map>
+#include <memory>
 #include <string>
 
 namespace llvm {
@@ -71,7 +72,7 @@ class FileEntry {
   bool IsValid;               // Is this \c FileEntry initialized and valid?
 
   /// The open file, if it is owned by the \p FileEntry.
-  mutable std::unique_ptr<vfs::File> File;
+  mutable std::unique_ptr<llvm::vfs::File> File;
 
 public:
   FileEntry()
@@ -114,7 +115,7 @@ struct FileData;
 /// as a single file.
 ///
 class FileManager : public RefCountedBase<FileManager> {
-  IntrusiveRefCntPtr<vfs::FileSystem> FS;
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
   FileSystemOptions FileSystemOpts;
 
   /// Cache for existing real directories.
@@ -165,7 +166,7 @@ class FileManager : public RefCountedBase<FileManager> {
   std::unique_ptr<FileSystemStatCache> StatCache;
 
   bool getStatValue(StringRef Path, FileData &Data, bool isFile,
-                    std::unique_ptr<vfs::File> *F);
+                    std::unique_ptr<llvm::vfs::File> *F);
 
   /// Add all ancestors of the given path (pointing to either a file
   /// or a directory) as virtual directories.
@@ -173,7 +174,7 @@ class FileManager : public RefCountedBase<FileManager> {
 
 public:
   FileManager(const FileSystemOptions &FileSystemOpts,
-              IntrusiveRefCntPtr<vfs::FileSystem> FS = nullptr);
+              IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
   ~FileManager();
 
   /// Installs the provided FileSystemStatCache object within
@@ -222,7 +223,7 @@ public:
   FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
   const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
 
-  IntrusiveRefCntPtr<vfs::FileSystem> getVirtualFileSystem() const {
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> getVirtualFileSystem() const {
     return FS;
   }
 
@@ -247,8 +248,7 @@ public:
   /// FileManager's FileSystemOptions.
   ///
   /// \returns false on success, true on error.
-  bool getNoncachedStatValue(StringRef Path,
-                             vfs::Status &Result);
+  bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result);
 
   /// Remove the real file \p Entry from the cache.
   void invalidateCache(const FileEntry *Entry);

include/clang/Basic/FileSystemStatCache.h

@@ -26,7 +26,7 @@
 #include <string>
 #include <utility>
 
-namespace clang {
+namespace llvm {
 
 namespace vfs {
 
@@ -34,6 +34,9 @@ class File;
 class FileSystem;
 
 } // namespace vfs
+} // namespace llvm
+
+namespace clang {
 
 // FIXME: should probably replace this with vfs::Status
 struct FileData {
@@ -82,8 +85,8 @@ public:
   /// implementation can optionally fill in \p F with a valid \p File object and
   /// the client guarantees that it will close it.
   static bool get(StringRef Path, FileData &Data, bool isFile,
-                  std::unique_ptr<vfs::File> *F, FileSystemStatCache *Cache,
-                  vfs::FileSystem &FS);
+                  std::unique_ptr<llvm::vfs::File> *F,
+                  FileSystemStatCache *Cache, llvm::vfs::FileSystem &FS);
 
   /// Sets the next stat call cache in the chain of stat caches.
   /// Takes ownership of the given stat cache.
@@ -106,11 +109,12 @@ protected:
   // unique_ptr. Optional<unique_ptr<vfs::File>&> might be nicer, but
   // Optional needs some work to support references so this isn't possible yet.
   virtual LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                               std::unique_ptr<vfs::File> *F,
-                               vfs::FileSystem &FS) = 0;
+                               std::unique_ptr<llvm::vfs::File> *F,
+                               llvm::vfs::FileSystem &FS) = 0;
 
   LookupResult statChained(StringRef Path, FileData &Data, bool isFile,
-                           std::unique_ptr<vfs::File> *F, vfs::FileSystem &FS) {
+                           std::unique_ptr<llvm::vfs::File> *F,
+                           llvm::vfs::FileSystem &FS) {
     if (FileSystemStatCache *Next = getNextStatCache())
       return Next->getStat(Path, Data, isFile, F, FS);
 
@@ -135,8 +139,8 @@ public:
   iterator end() const { return StatCalls.end(); }
 
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                       std::unique_ptr<vfs::File> *F,
-                       vfs::FileSystem &FS) override;
+                       std::unique_ptr<llvm::vfs::File> *F,
+                       llvm::vfs::FileSystem &FS) override;
 };
 
 } // namespace clang

include/clang/Basic/VirtualFileSystem.h

@@ -1,529 +0,0 @@
-//===- VirtualFileSystem.h - Virtual File System Layer ----------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-/// \file
-/// Defines the virtual file system interface vfs::FileSystem.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
-#define LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
-
-#include "clang/Basic/LLVM.h"
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
-#include "llvm/ADT/None.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/Support/Chrono.h"
-#include "llvm/Support/ErrorOr.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/SourceMgr.h"
-#include <cassert>
-#include <cstdint>
-#include <ctime>
-#include <memory>
-#include <stack>
-#include <string>
-#include <system_error>
-#include <utility>
-#include <vector>
-
-namespace llvm {
-
-class MemoryBuffer;
-
-} // namespace llvm
-
-namespace clang {
-namespace vfs {
-
-/// The result of a \p status operation.
-class Status {
-  std::string Name;
-  llvm::sys::fs::UniqueID UID;
-  llvm::sys::TimePoint<> MTime;
-  uint32_t User;
-  uint32_t Group;
-  uint64_t Size;
-  llvm::sys::fs::file_type Type = llvm::sys::fs::file_type::status_error;
-  llvm::sys::fs::perms Perms;
-
-public:
-   // FIXME: remove when files support multiple names
-  bool IsVFSMapped = false;
-
-  Status() = default;
-  Status(const llvm::sys::fs::file_status &Status);
-  Status(StringRef Name, llvm::sys::fs::UniqueID UID,
-         llvm::sys::TimePoint<> MTime, uint32_t User, uint32_t Group,
-         uint64_t Size, llvm::sys::fs::file_type Type,
-         llvm::sys::fs::perms Perms);
-
-  /// Get a copy of a Status with a different name.
-  static Status copyWithNewName(const Status &In, StringRef NewName);
-  static Status copyWithNewName(const llvm::sys::fs::file_status &In,
-                                StringRef NewName);
-
-  /// Returns the name that should be used for this file or directory.
-  StringRef getName() const { return Name; }
-
-  /// @name Status interface from llvm::sys::fs
-  /// @{
-  llvm::sys::fs::file_type getType() const { return Type; }
-  llvm::sys::fs::perms getPermissions() const { return Perms; }
-  llvm::sys::TimePoint<> getLastModificationTime() const { return MTime; }
-  llvm::sys::fs::UniqueID getUniqueID() const { return UID; }
-  uint32_t getUser() const { return User; }
-  uint32_t getGroup() const { return Group; }
-  uint64_t getSize() const { return Size; }
-  /// @}
-  /// @name Status queries
-  /// These are static queries in llvm::sys::fs.
-  /// @{
-  bool equivalent(const Status &Other) const;
-  bool isDirectory() const;
-  bool isRegularFile() const;
-  bool isOther() const;
-  bool isSymlink() const;
-  bool isStatusKnown() const;
-  bool exists() const;
-  /// @}
-};
-
-/// Represents an open file.
-class File {
-public:
-  /// Destroy the file after closing it (if open).
-  /// Sub-classes should generally call close() inside their destructors.  We
-  /// cannot do that from the base class, since close is virtual.
-  virtual ~File();
-
-  /// Get the status of the file.
-  virtual llvm::ErrorOr<Status> status() = 0;
-
-  /// Get the name of the file
-  virtual llvm::ErrorOr<std::string> getName() {
-    if (auto Status = status())
-      return Status->getName().str();
-    else
-      return Status.getError();
-  }
-
-  /// Get the contents of the file as a \p MemoryBuffer.
-  virtual llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
-  getBuffer(const Twine &Name, int64_t FileSize = -1,
-            bool RequiresNullTerminator = true, bool IsVolatile = false) = 0;
-
-  /// Closes the file.
-  virtual std::error_code close() = 0;
-};
-
-/// A member of a directory, yielded by a directory_iterator.
-/// Only information available on most platforms is included.
-class directory_entry {
-  std::string Path;
-  llvm::sys::fs::file_type Type;
-
-public:
-  directory_entry() = default;
-  directory_entry(std::string Path, llvm::sys::fs::file_type Type)
-      : Path(std::move(Path)), Type(Type) {}
-
-  llvm::StringRef path() const { return Path; }
-  llvm::sys::fs::file_type type() const { return Type; }
-};
-
-namespace detail {
-
-/// An interface for virtual file systems to provide an iterator over the
-/// (non-recursive) contents of a directory.
-struct DirIterImpl {
-  virtual ~DirIterImpl();
-
-  /// Sets \c CurrentEntry to the next entry in the directory on success,
-  /// to directory_entry() at end,  or returns a system-defined \c error_code.
-  virtual std::error_code increment() = 0;
-
-  directory_entry CurrentEntry;
-};
-
-} // namespace detail
-
-/// An input iterator over the entries in a virtual path, similar to
-/// llvm::sys::fs::directory_iterator.
-class directory_iterator {
-  std::shared_ptr<detail::DirIterImpl> Impl; // Input iterator semantics on copy
-
-public:
-  directory_iterator(std::shared_ptr<detail::DirIterImpl> I)
-      : Impl(std::move(I)) {
-    assert(Impl.get() != nullptr && "requires non-null implementation");
-    if (Impl->CurrentEntry.path().empty())
-      Impl.reset(); // Normalize the end iterator to Impl == nullptr.
-  }
-
-  /// Construct an 'end' iterator.
-  directory_iterator() = default;
-
-  /// Equivalent to operator++, with an error code.
-  directory_iterator &increment(std::error_code &EC) {
-    assert(Impl && "attempting to increment past end");
-    EC = Impl->increment();
-    if (Impl->CurrentEntry.path().empty())
-      Impl.reset(); // Normalize the end iterator to Impl == nullptr.
-    return *this;
-  }
-
-  const directory_entry &operator*() const { return Impl->CurrentEntry; }
-  const directory_entry *operator->() const { return &Impl->CurrentEntry; }
-
-  bool operator==(const directory_iterator &RHS) const {
-    if (Impl && RHS.Impl)
-      return Impl->CurrentEntry.path() == RHS.Impl->CurrentEntry.path();
-    return !Impl && !RHS.Impl;
-  }
-  bool operator!=(const directory_iterator &RHS) const {
-    return !(*this == RHS);
-  }
-};
-
-class FileSystem;
-
-/// An input iterator over the recursive contents of a virtual path,
-/// similar to llvm::sys::fs::recursive_directory_iterator.
-class recursive_directory_iterator {
-  using IterState =
-      std::stack<directory_iterator, std::vector<directory_iterator>>;
-
-  FileSystem *FS;
-  std::shared_ptr<IterState> State; // Input iterator semantics on copy.
-
-public:
-  recursive_directory_iterator(FileSystem &FS, const Twine &Path,
-                               std::error_code &EC);
-
-  /// Construct an 'end' iterator.
-  recursive_directory_iterator() = default;
-
-  /// Equivalent to operator++, with an error code.
-  recursive_directory_iterator &increment(std::error_code &EC);
-
-  const directory_entry &operator*() const { return *State->top(); }
-  const directory_entry *operator->() const { return &*State->top(); }
-
-  bool operator==(const recursive_directory_iterator &Other) const {
-    return State == Other.State; // identity
-  }
-  bool operator!=(const recursive_directory_iterator &RHS) const {
-    return !(*this == RHS);
-  }
-
-  /// Gets the current level. Starting path is at level 0.
-  int level() const {
-    assert(!State->empty() && "Cannot get level without any iteration state");
-    return State->size()-1;
-  }
-};
-
-/// The virtual file system interface.
-class FileSystem : public llvm::ThreadSafeRefCountedBase<FileSystem> {
-public:
-  virtual ~FileSystem();
-
-  /// Get the status of the entry at \p Path, if one exists.
-  virtual llvm::ErrorOr<Status> status(const Twine &Path) = 0;
-
-  /// Get a \p File object for the file at \p Path, if one exists.
-  virtual llvm::ErrorOr<std::unique_ptr<File>>
-  openFileForRead(const Twine &Path) = 0;
-
-  /// This is a convenience method that opens a file, gets its content and then
-  /// closes the file.
-  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
-  getBufferForFile(const Twine &Name, int64_t FileSize = -1,
-                   bool RequiresNullTerminator = true, bool IsVolatile = false);
-
-  /// Get a directory_iterator for \p Dir.
-  /// \note The 'end' iterator is directory_iterator().
-  virtual directory_iterator dir_begin(const Twine &Dir,
-                                       std::error_code &EC) = 0;
-
-  /// Set the working directory. This will affect all following operations on
-  /// this file system and may propagate down for nested file systems.
-  virtual std::error_code setCurrentWorkingDirectory(const Twine &Path) = 0;
-
-  /// Get the working directory of this file system.
-  virtual llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const = 0;
-
-  /// Gets real path of \p Path e.g. collapse all . and .. patterns, resolve
-  /// symlinks. For real file system, this uses `llvm::sys::fs::real_path`.
-  /// This returns errc::operation_not_permitted if not implemented by subclass.
-  virtual std::error_code getRealPath(const Twine &Path,
-                                      SmallVectorImpl<char> &Output) const;
-
-  /// Check whether a file exists. Provided for convenience.
-  bool exists(const Twine &Path);
-
-  /// Make \a Path an absolute path.
-  ///
-  /// Makes \a Path absolute using the current directory if it is not already.
-  /// An empty \a Path will result in the current directory.
-  ///
-  /// /absolute/path   => /absolute/path
-  /// relative/../path => <current-directory>/relative/../path
-  ///
-  /// \param Path A path that is modified to be an absolute path.
-  /// \returns success if \a path has been made absolute, otherwise a
-  ///          platform-specific error_code.
-  std::error_code makeAbsolute(SmallVectorImpl<char> &Path) const;
-};
-
-/// Gets an \p vfs::FileSystem for the 'real' file system, as seen by
-/// the operating system.
-IntrusiveRefCntPtr<FileSystem> getRealFileSystem();
-
-/// A file system that allows overlaying one \p AbstractFileSystem on top
-/// of another.
-///
-/// Consists of a stack of >=1 \p FileSystem objects, which are treated as being
-/// one merged file system. When there is a directory that exists in more than
-/// one file system, the \p OverlayFileSystem contains a directory containing
-/// the union of their contents.  The attributes (permissions, etc.) of the
-/// top-most (most recently added) directory are used.  When there is a file
-/// that exists in more than one file system, the file in the top-most file
-/// system overrides the other(s).
-class OverlayFileSystem : public FileSystem {
-  using FileSystemList = SmallVector<IntrusiveRefCntPtr<FileSystem>, 1>;
-
-  /// The stack of file systems, implemented as a list in order of
-  /// their addition.
-  FileSystemList FSList;
-
-public:
-  OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> Base);
-
-  /// Pushes a file system on top of the stack.
-  void pushOverlay(IntrusiveRefCntPtr<FileSystem> FS);
-
-  llvm::ErrorOr<Status> status(const Twine &Path) override;
-  llvm::ErrorOr<std::unique_ptr<File>>
-  openFileForRead(const Twine &Path) override;
-  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
-  std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override;
-
-  using iterator = FileSystemList::reverse_iterator;
-  using const_iterator = FileSystemList::const_reverse_iterator;
-
-  /// Get an iterator pointing to the most recently added file system.
-  iterator overlays_begin() { return FSList.rbegin(); }
-  const_iterator overlays_begin() const { return FSList.rbegin(); }
-
-  /// Get an iterator pointing one-past the least recently added file
-  /// system.
-  iterator overlays_end() { return FSList.rend(); }
-  const_iterator overlays_end() const { return FSList.rend(); }
-};
-
-/// By default, this delegates all calls to the underlying file system. This
-/// is useful when derived file systems want to override some calls and still
-/// proxy other calls.
-class ProxyFileSystem : public FileSystem {
-public:
-  explicit ProxyFileSystem(IntrusiveRefCntPtr<FileSystem> FS)
-      : FS(std::move(FS)) {}
-
-  llvm::ErrorOr<Status> status(const Twine &Path) override {
-    return FS->status(Path);
-  }
-  llvm::ErrorOr<std::unique_ptr<File>>
-  openFileForRead(const Twine &Path) override {
-    return FS->openFileForRead(Path);
-  }
-  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override {
-    return FS->dir_begin(Dir, EC);
-  }
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
-    return FS->getCurrentWorkingDirectory();
-  }
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
-    return FS->setCurrentWorkingDirectory(Path);
-  }
-  std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override {
-    return FS->getRealPath(Path, Output);
-  }
-
-protected:
-  FileSystem &getUnderlyingFS() { return *FS; }
-
-private:
-  IntrusiveRefCntPtr<FileSystem> FS;
-};
-
-namespace detail {
-
-class InMemoryDirectory;
-class InMemoryFile;
-
-} // namespace detail
-
-/// An in-memory file system.
-class InMemoryFileSystem : public FileSystem {
-  std::unique_ptr<detail::InMemoryDirectory> Root;
-  std::string WorkingDirectory;
-  bool UseNormalizedPaths = true;
-
-  /// If HardLinkTarget is non-null, a hardlink is created to the To path which
-  /// must be a file. If it is null then it adds the file as the public addFile.
-  bool addFile(const Twine &Path, time_t ModificationTime,
-               std::unique_ptr<llvm::MemoryBuffer> Buffer,
-               Optional<uint32_t> User, Optional<uint32_t> Group,
-               Optional<llvm::sys::fs::file_type> Type,
-               Optional<llvm::sys::fs::perms> Perms,
-               const detail::InMemoryFile *HardLinkTarget);
-
-public:
-  explicit InMemoryFileSystem(bool UseNormalizedPaths = true);
-  ~InMemoryFileSystem() override;
-
-  /// Add a file containing a buffer or a directory to the VFS with a
-  /// path. The VFS owns the buffer.  If present, User, Group, Type
-  /// and Perms apply to the newly-created file or directory.
-  /// \return true if the file or directory was successfully added,
-  /// false if the file or directory already exists in the file system with
-  /// different contents.
-  bool addFile(const Twine &Path, time_t ModificationTime,
-               std::unique_ptr<llvm::MemoryBuffer> Buffer,
-               Optional<uint32_t> User = None, Optional<uint32_t> Group = None,
-               Optional<llvm::sys::fs::file_type> Type = None,
-               Optional<llvm::sys::fs::perms> Perms = None);
-
-  /// Add a hard link to a file.
-  /// Here hard links are not intended to be fully equivalent to the classical
-  /// filesystem. Both the hard link and the file share the same buffer and
-  /// status (and thus have the same UniqueID). Because of this there is no way
-  /// to distinguish between the link and the file after the link has been
-  /// added.
-  ///
-  /// The To path must be an existing file or a hardlink. The From file must not
-  /// have been added before. The To Path must not be a directory. The From Node
-  /// is added as a hard link which points to the resolved file of To Node.
-  /// \return true if the above condition is satisfied and hardlink was
-  /// successfully created, false otherwise.
-  bool addHardLink(const Twine &From, const Twine &To);
-
-  /// Add a buffer to the VFS with a path. The VFS does not own the buffer.
-  /// If present, User, Group, Type and Perms apply to the newly-created file
-  /// or directory.
-  /// \return true if the file or directory was successfully added,
-  /// false if the file or directory already exists in the file system with
-  /// different contents.
-  bool addFileNoOwn(const Twine &Path, time_t ModificationTime,
-                    llvm::MemoryBuffer *Buffer,
-                    Optional<uint32_t> User = None,
-                    Optional<uint32_t> Group = None,
-                    Optional<llvm::sys::fs::file_type> Type = None,
-                    Optional<llvm::sys::fs::perms> Perms = None);
-
-  std::string toString() const;
-
-  /// Return true if this file system normalizes . and .. in paths.
-  bool useNormalizedPaths() const { return UseNormalizedPaths; }
-
-  llvm::ErrorOr<Status> status(const Twine &Path) override;
-  llvm::ErrorOr<std::unique_ptr<File>>
-  openFileForRead(const Twine &Path) override;
-  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
-
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
-    return WorkingDirectory;
-  }
-  /// Canonicalizes \p Path by combining with the current working
-  /// directory and normalizing the path (e.g. remove dots). If the current
-  /// working directory is not set, this returns errc::operation_not_permitted.
-  ///
-  /// This doesn't resolve symlinks as they are not supported in in-memory file
-  /// system.
-  std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override;
-
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
-};
-
-/// Get a globally unique ID for a virtual file or directory.
-llvm::sys::fs::UniqueID getNextVirtualUniqueID();
-
-/// Gets a \p FileSystem for a virtual file system described in YAML
-/// format.
-IntrusiveRefCntPtr<FileSystem>
-getVFSFromYAML(std::unique_ptr<llvm::MemoryBuffer> Buffer,
-               llvm::SourceMgr::DiagHandlerTy DiagHandler,
-               StringRef YAMLFilePath,
-               void *DiagContext = nullptr,
-               IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
-
-struct YAMLVFSEntry {
-  template <typename T1, typename T2> YAMLVFSEntry(T1 &&VPath, T2 &&RPath)
-      : VPath(std::forward<T1>(VPath)), RPath(std::forward<T2>(RPath)) {}
-  std::string VPath;
-  std::string RPath;
-};
-
-/// Collect all pairs of <virtual path, real path> entries from the
-/// \p YAMLFilePath. This is used by the module dependency collector to forward
-/// the entries into the reproducer output VFS YAML file.
-void collectVFSFromYAML(
-    std::unique_ptr<llvm::MemoryBuffer> Buffer,
-    llvm::SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
-    SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
-    void *DiagContext = nullptr,
-    IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
-
-class YAMLVFSWriter {
-  std::vector<YAMLVFSEntry> Mappings;
-  Optional<bool> IsCaseSensitive;
-  Optional<bool> IsOverlayRelative;
-  Optional<bool> UseExternalNames;
-  Optional<bool> IgnoreNonExistentContents;
-  std::string OverlayDir;
-
-public:
-  YAMLVFSWriter() = default;
-
-  void addFileMapping(StringRef VirtualPath, StringRef RealPath);
-
-  void setCaseSensitivity(bool CaseSensitive) {
-    IsCaseSensitive = CaseSensitive;
-  }
-
-  void setUseExternalNames(bool UseExtNames) {
-    UseExternalNames = UseExtNames;
-  }
-
-  void setIgnoreNonExistentContents(bool IgnoreContents) {
-    IgnoreNonExistentContents = IgnoreContents;
-  }
-
-  void setOverlayDir(StringRef OverlayDirectory) {
-    IsOverlayRelative = true;
-    OverlayDir.assign(OverlayDirectory.str());
-  }
-
-  void write(llvm::raw_ostream &OS);
-};
-
-} // namespace vfs
-} // namespace clang
-
-#endif // LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H

include/clang/Driver/Distro.h

@@ -10,7 +10,7 @@
 #ifndef LLVM_CLANG_DRIVER_DISTRO_H
 #define LLVM_CLANG_DRIVER_DISTRO_H
 
-#include "clang/Basic/VirtualFileSystem.h"
+#include "llvm/Support/VirtualFileSystem.h"
 
 namespace clang {
 namespace driver {
@@ -80,7 +80,7 @@ public:
   Distro(DistroType D) : DistroVal(D) {}
 
   /// Detects the distribution using specified VFS.
-  explicit Distro(clang::vfs::FileSystem& VFS);
+  explicit Distro(llvm::vfs::FileSystem &VFS);
 
   bool operator==(const Distro &Other) const {
     return DistroVal == Other.DistroVal;

include/clang/Driver/Driver.h

@@ -28,13 +28,12 @@
 
 namespace llvm {
 class Triple;
-}
-
-namespace clang {
-
 namespace vfs {
 class FileSystem;
 }
+} // namespace llvm
+
+namespace clang {
 
 namespace driver {
 
@@ -61,7 +60,7 @@ class Driver {
 
   DiagnosticsEngine &Diags;
 
-  IntrusiveRefCntPtr<vfs::FileSystem> VFS;
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS;
 
   enum DriverMode {
     GCCMode,
@@ -284,7 +283,7 @@ private:
 public:
   Driver(StringRef ClangExecutable, StringRef TargetTriple,
          DiagnosticsEngine &Diags,
-         IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
+         IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
 
   /// @name Accessors
   /// @{
@@ -298,7 +297,7 @@ public:
 
   const DiagnosticsEngine &getDiags() const { return Diags; }
 
-  vfs::FileSystem &getVFS() const { return *VFS; }
+  llvm::vfs::FileSystem &getVFS() const { return *VFS; }
 
   bool getCheckInputsExist() const { return CheckInputsExist; }
 

include/clang/Driver/ToolChain.h

@@ -36,17 +36,16 @@ class ArgList;
 class DerivedArgList;
 
 } // namespace opt
-} // namespace llvm
-
-namespace clang {
-
-class ObjCRuntime;
-
 namespace vfs {
 
 class FileSystem;
 
 } // namespace vfs
+} // namespace llvm
+
+namespace clang {
+
+class ObjCRuntime;
 
 namespace driver {
 
@@ -183,7 +182,7 @@ public:
   // Accessors
 
   const Driver &getDriver() const { return D; }
-  vfs::FileSystem &getVFS() const;
+  llvm::vfs::FileSystem &getVFS() const;
   const llvm::Triple &getTriple() const { return Triple; }
 
   /// Get the toolchain's aux triple, if it has one.

include/clang/Format/Format.h

@@ -22,16 +22,18 @@
 #include "llvm/Support/Regex.h"
 #include <system_error>
 
+namespace llvm {
+namespace vfs {
+class FileSystem;
+}
+} // namespace llvm
+
 namespace clang {
 
 class Lexer;
 class SourceManager;
 class DiagnosticConsumer;
 
-namespace vfs {
-class FileSystem;
-}
-
 namespace format {
 
 enum class ParseError { Success = 0, Error, Unsuitable };
@@ -2039,7 +2041,7 @@ extern const char *DefaultFallbackStyle;
 llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
                                      StringRef FallbackStyle,
                                      StringRef Code = "",
-                                     vfs::FileSystem *FS = nullptr);
+                                     llvm::vfs::FileSystem *FS = nullptr);
 
 // Guesses the language from the ``FileName`` and ``Code`` to be formatted.
 // Defaults to FormatStyle::LK_Cpp.

include/clang/Frontend/ASTUnit.h

@@ -51,6 +51,11 @@ namespace llvm {
 
 class MemoryBuffer;
 
+namespace vfs {
+
+class FileSystem;
+
+} // namespace vfs
 } // namespace llvm
 
 namespace clang {
@@ -75,12 +80,6 @@ class PreprocessorOptions;
 class Sema;
 class TargetInfo;
 
-namespace vfs {
-
-class FileSystem;
-
-} // namespace vfs
-
 /// \brief Enumerates the available scopes for skipping function bodies.
 enum class SkipFunctionBodiesScope { None, Preamble, PreambleAndMainFile };
 
@@ -365,12 +364,12 @@ private:
 
   bool Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
              std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer,
-             IntrusiveRefCntPtr<vfs::FileSystem> VFS);
+             IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS);
 
   std::unique_ptr<llvm::MemoryBuffer> getMainBufferWithPrecompiledPreamble(
       std::shared_ptr<PCHContainerOperations> PCHContainerOps,
       CompilerInvocation &PreambleInvocationIn,
-      IntrusiveRefCntPtr<vfs::FileSystem> VFS, bool AllowRebuild = true,
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool AllowRebuild = true,
       unsigned MaxLines = 0);
   void RealizeTopLevelDeclsFromPreamble();
 
@@ -698,17 +697,17 @@ private:
   /// of this translation unit should be precompiled, to improve the performance
   /// of reparsing. Set to zero to disable preambles.
   ///
-  /// \param VFS - A vfs::FileSystem to be used for all file accesses. Note that
-  /// preamble is saved to a temporary directory on a RealFileSystem, so in order
-  /// for it to be loaded correctly, VFS should have access to it(i.e., be an
-  /// overlay over RealFileSystem).
+  /// \param VFS - A llvm::vfs::FileSystem to be used for all file accesses.
+  /// Note that preamble is saved to a temporary directory on a RealFileSystem,
+  /// so in order for it to be loaded correctly, VFS should have access to
+  /// it(i.e., be an overlay over RealFileSystem).
   ///
   /// \returns \c true if a catastrophic failure occurred (which means that the
   /// \c ASTUnit itself is invalid), or \c false otherwise.
   bool LoadFromCompilerInvocation(
       std::shared_ptr<PCHContainerOperations> PCHContainerOps,
       unsigned PrecompilePreambleAfterNParses,
-      IntrusiveRefCntPtr<vfs::FileSystem> VFS);
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS);
 
 public:
   /// Create an ASTUnit from a source file, via a CompilerInvocation
@@ -798,10 +797,11 @@ public:
   /// (e.g. because the PCH could not be loaded), this accepts the ASTUnit
   /// mainly to allow the caller to see the diagnostics.
   ///
-  /// \param VFS - A vfs::FileSystem to be used for all file accesses. Note that
-  /// preamble is saved to a temporary directory on a RealFileSystem, so in order
-  /// for it to be loaded correctly, VFS should have access to it(i.e., be an
-  /// overlay over RealFileSystem). RealFileSystem will be used if \p VFS is nullptr.
+  /// \param VFS - A llvm::vfs::FileSystem to be used for all file accesses.
+  /// Note that preamble is saved to a temporary directory on a RealFileSystem,
+  /// so in order for it to be loaded correctly, VFS should have access to
+  /// it(i.e., be an overlay over RealFileSystem). RealFileSystem will be used
+  /// if \p VFS is nullptr.
   ///
   // FIXME: Move OnlyLocalDecls, UseBumpAllocator to setters on the ASTUnit, we
   // shouldn't need to specify them at construction time.
@@ -823,22 +823,22 @@ public:
       bool ForSerialization = false,
       llvm::Optional<StringRef> ModuleFormat = llvm::None,
       std::unique_ptr<ASTUnit> *ErrAST = nullptr,
-      IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
 
   /// Reparse the source files using the same command-line options that
   /// were originally used to produce this translation unit.
   ///
-  /// \param VFS - A vfs::FileSystem to be used for all file accesses. Note that
-  /// preamble is saved to a temporary directory on a RealFileSystem, so in order
-  /// for it to be loaded correctly, VFS should give an access to this(i.e. be an
-  /// overlay over RealFileSystem). FileMgr->getVirtualFileSystem() will be used if
-  /// \p VFS is nullptr.
+  /// \param VFS - A llvm::vfs::FileSystem to be used for all file accesses.
+  /// Note that preamble is saved to a temporary directory on a RealFileSystem,
+  /// so in order for it to be loaded correctly, VFS should give an access to
+  /// this(i.e. be an overlay over RealFileSystem).
+  /// FileMgr->getVirtualFileSystem() will be used if \p VFS is nullptr.
   ///
   /// \returns True if a failure occurred that causes the ASTUnit not to
   /// contain any translation-unit information, false otherwise.
   bool Reparse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                ArrayRef<RemappedFile> RemappedFiles = None,
-               IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
+               IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
 
   /// Free data that will be re-generated on the next parse.
   ///

include/clang/Frontend/CompilerInstance.h

@@ -83,7 +83,7 @@ class CompilerInstance : public ModuleLoader {
   IntrusiveRefCntPtr<TargetInfo> AuxTarget;
 
   /// The virtual file system.
-  IntrusiveRefCntPtr<vfs::FileSystem> VirtualFileSystem;
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VirtualFileSystem;
 
   /// The file manager.
   IntrusiveRefCntPtr<FileManager> FileMgr;
@@ -384,7 +384,7 @@ public:
 
   bool hasVirtualFileSystem() const { return VirtualFileSystem != nullptr; }
 
-  vfs::FileSystem &getVirtualFileSystem() const {
+  llvm::vfs::FileSystem &getVirtualFileSystem() const {
     assert(hasVirtualFileSystem() &&
            "Compiler instance has no virtual file system");
     return *VirtualFileSystem;
@@ -394,7 +394,7 @@ public:
   ///
   /// \note Most clients should use setFileManager, which will implicitly reset
   /// the virtual file system to the one contained in the file manager.
-  void setVirtualFileSystem(IntrusiveRefCntPtr<vfs::FileSystem> FS) {
+  void setVirtualFileSystem(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
     VirtualFileSystem = std::move(FS);
   }
 

include/clang/Frontend/CompilerInvocation.h

@@ -35,6 +35,12 @@ class ArgList;
 
 } // namespace opt
 
+namespace vfs {
+
+class FileSystem;
+
+} // namespace vfs
+
 } // namespace llvm
 
 namespace clang {
@@ -217,20 +223,13 @@ public:
   /// @}
 };
 
-namespace vfs {
-
-class FileSystem;
-
-} // namespace vfs
-
-IntrusiveRefCntPtr<vfs::FileSystem>
+IntrusiveRefCntPtr<llvm::vfs::FileSystem>
 createVFSFromCompilerInvocation(const CompilerInvocation &CI,
                                 DiagnosticsEngine &Diags);
 
-IntrusiveRefCntPtr<vfs::FileSystem>
-createVFSFromCompilerInvocation(const CompilerInvocation &CI,
-                                DiagnosticsEngine &Diags,
-                                IntrusiveRefCntPtr<vfs::FileSystem> BaseFS);
+IntrusiveRefCntPtr<llvm::vfs::FileSystem> createVFSFromCompilerInvocation(
+    const CompilerInvocation &CI, DiagnosticsEngine &Diags,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS);
 
 } // namespace clang
 

include/clang/Frontend/PrecompiledPreamble.h

@@ -26,13 +26,12 @@
 
 namespace llvm {
 class MemoryBuffer;
-}
-
-namespace clang {
 namespace vfs {
 class FileSystem;
 }
+} // namespace llvm
 
+namespace clang {
 class CompilerInstance;
 class CompilerInvocation;
 class DeclGroupRef;
@@ -80,7 +79,8 @@ public:
   static llvm::ErrorOr<PrecompiledPreamble>
   Build(const CompilerInvocation &Invocation,
         const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
-        DiagnosticsEngine &Diagnostics, IntrusiveRefCntPtr<vfs::FileSystem> VFS,
+        DiagnosticsEngine &Diagnostics,
+        IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
         std::shared_ptr<PCHContainerOperations> PCHContainerOps,
         bool StoreInMemory, PreambleCallbacks &Callbacks);
 
@@ -99,7 +99,7 @@ public:
   /// MainFileBuffer) of the main file.
   bool CanReuse(const CompilerInvocation &Invocation,
                 const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
-                vfs::FileSystem *VFS) const;
+                llvm::vfs::FileSystem *VFS) const;
 
   /// Changes options inside \p CI to use PCH from this preamble. Also remaps
   /// main file to \p MainFileBuffer and updates \p VFS to ensure the preamble
@@ -110,14 +110,14 @@ public:
   /// responsible for making sure the PrecompiledPreamble instance outlives the
   /// compiler run and the AST that will be using the PCH.
   void AddImplicitPreamble(CompilerInvocation &CI,
-                           IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+                           IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
                            llvm::MemoryBuffer *MainFileBuffer) const;
 
   /// Configure \p CI to use this preamble.
   /// Like AddImplicitPreamble, but doesn't assume CanReuse() is true.
   /// If this preamble does not match the file, it may parse differently.
   void OverridePreamble(CompilerInvocation &CI,
-                        IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+                        IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
                         llvm::MemoryBuffer *MainFileBuffer) const;
 
 private:
@@ -233,15 +233,16 @@ private:
   /// Helper function to set up PCH for the preamble into \p CI and \p VFS to
   /// with the specified \p Bounds.
   void configurePreamble(PreambleBounds Bounds, CompilerInvocation &CI,
-                         IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+                         IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
                          llvm::MemoryBuffer *MainFileBuffer) const;
 
   /// Sets up the PreprocessorOptions and changes VFS, so that PCH stored in \p
   /// Storage is accessible to clang. This method is an implementation detail of
   /// AddImplicitPreamble.
-  static void setupPreambleStorage(const PCHStorage &Storage,
-                                   PreprocessorOptions &PreprocessorOpts,
-                                   IntrusiveRefCntPtr<vfs::FileSystem> &VFS);
+  static void
+  setupPreambleStorage(const PCHStorage &Storage,
+                       PreprocessorOptions &PreprocessorOpts,
+                       IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS);
 
   /// Manages the memory buffer or temporary file that stores the PCH.
   PCHStorage Storage;

include/clang/Frontend/Utils.h

@@ -16,13 +16,13 @@
 
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VirtualFileSystem.h"
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Option/OptSpecifier.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <cstdint>
 #include <memory>
 #include <string>
@@ -134,7 +134,7 @@ class ModuleDependencyCollector : public DependencyCollector {
   std::string DestDir;
   bool HasErrors = false;
   llvm::StringSet<> Seen;
-  vfs::YAMLVFSWriter VFSWriter;
+  llvm::vfs::YAMLVFSWriter VFSWriter;
   llvm::StringMap<std::string> SymLinkMap;
 
   bool getRealPath(StringRef SrcPath, SmallVectorImpl<char> &Result);
@@ -201,7 +201,7 @@ std::unique_ptr<CompilerInvocation> createInvocationFromCommandLine(
     ArrayRef<const char *> Args,
     IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
         IntrusiveRefCntPtr<DiagnosticsEngine>(),
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS = nullptr);
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);
 
 /// Return the value of the last argument as an integer, or a default. If Diags
 /// is non-null, emits an error if the argument is given, but non-integral.

include/clang/Tooling/StandaloneExecution.h

@@ -37,7 +37,8 @@ public:
   StandaloneToolExecutor(
       const CompilationDatabase &Compilations,
       llvm::ArrayRef<std::string> SourcePaths,
-      IntrusiveRefCntPtr<vfs::FileSystem> BaseFS = vfs::getRealFileSystem(),
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS =
+          llvm::vfs::getRealFileSystem(),
       std::shared_ptr<PCHContainerOperations> PCHContainerOps =
           std::make_shared<PCHContainerOperations>());
 

include/clang/Tooling/Tooling.h

@@ -33,7 +33,6 @@
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Frontend/PCHContainerOperations.h"
 #include "clang/Tooling/ArgumentsAdjusters.h"
@@ -44,6 +43,7 @@
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Option/Option.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <memory>
 #include <string>
 #include <utility>
@@ -190,7 +190,7 @@ bool runToolOnCodeWithArgs(
 // Similar to the overload except this takes a VFS.
 bool runToolOnCodeWithArgs(
     FrontendAction *ToolAction, const Twine &Code,
-    llvm::IntrusiveRefCntPtr<vfs::FileSystem> VFS,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
     const std::vector<std::string> &Args, const Twine &FileName = "input.cc",
     const Twine &ToolName = "clang-tool",
     std::shared_ptr<PCHContainerOperations> PCHContainerOps =
@@ -319,8 +319,8 @@ public:
             ArrayRef<std::string> SourcePaths,
             std::shared_ptr<PCHContainerOperations> PCHContainerOps =
                 std::make_shared<PCHContainerOperations>(),
-            IntrusiveRefCntPtr<vfs::FileSystem> BaseFS =
-                vfs::getRealFileSystem());
+            IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS =
+                llvm::vfs::getRealFileSystem());
 
   ~ClangTool();
 
@@ -373,8 +373,8 @@ private:
   std::vector<std::string> SourcePaths;
   std::shared_ptr<PCHContainerOperations> PCHContainerOps;
 
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem;
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem;
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem;
   llvm::IntrusiveRefCntPtr<FileManager> Files;
 
   // Contains a list of pairs (<file name>, <file content>).
@@ -467,7 +467,7 @@ inline std::unique_ptr<FrontendActionFactory> newFrontendActionFactory(
 std::string getAbsolutePath(StringRef File);
 
 /// An overload of getAbsolutePath that works over the provided \p FS.
-llvm::Expected<std::string> getAbsolutePath(vfs::FileSystem &FS,
+llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
                                             StringRef File);
 
 /// Changes CommandLine to contain implicit flags that would have been

lib/Basic/CMakeLists.txt

@@ -94,7 +94,6 @@ add_clang_library(clangBasic
   Targets/XCore.cpp
   TokenKinds.cpp
   Version.cpp
-  VirtualFileSystem.cpp
   Warnings.cpp
   XRayInstr.cpp
   XRayLists.cpp

lib/Basic/FileManager.cpp

@@ -49,7 +49,7 @@ using namespace clang;
 //===----------------------------------------------------------------------===//
 
 FileManager::FileManager(const FileSystemOptions &FSO,
-                         IntrusiveRefCntPtr<vfs::FileSystem> FS)
+                         IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS)
     : FS(std::move(FS)), FileSystemOpts(FSO), SeenDirEntries(64),
       SeenFileEntries(64), NextFileUID(0) {
   NumDirLookups = NumFileLookups = 0;
@@ -58,7 +58,7 @@ FileManager::FileManager(const FileSystemOptions &FSO,
   // If the caller doesn't provide a virtual file system, just grab the real
   // file system.
   if (!this->FS)
-    this->FS = vfs::getRealFileSystem();
+    this->FS = llvm::vfs::getRealFileSystem();
 }
 
 FileManager::~FileManager() = default;
@@ -252,7 +252,7 @@ const FileEntry *FileManager::getFile(StringRef Filename, bool openFile,
   // FIXME: This will reduce the # syscalls.
 
   // Nope, there isn't.  Check to see if the file exists.
-  std::unique_ptr<vfs::File> F;
+  std::unique_ptr<llvm::vfs::File> F;
   FileData Data;
   if (getStatValue(InterndFileName, Data, true, openFile ? &F : nullptr)) {
     // There's no real file at the given path.
@@ -475,7 +475,7 @@ FileManager::getBufferForFile(StringRef Filename, bool isVolatile) {
 /// false if it's an existent real file.  If FileDescriptor is NULL,
 /// do directory look-up instead of file look-up.
 bool FileManager::getStatValue(StringRef Path, FileData &Data, bool isFile,
-                               std::unique_ptr<vfs::File> *F) {
+                               std::unique_ptr<llvm::vfs::File> *F) {
   // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be
   // absolute!
   if (FileSystemOpts.WorkingDir.empty())
@@ -489,11 +489,11 @@ bool FileManager::getStatValue(StringRef Path, FileData &Data, bool isFile,
 }
 
 bool FileManager::getNoncachedStatValue(StringRef Path,
-                                        vfs::Status &Result) {
+                                        llvm::vfs::Status &Result) {
   SmallString<128> FilePath(Path);
   FixupRelativePath(FilePath);
 
-  llvm::ErrorOr<vfs::Status> S = FS->status(FilePath.c_str());
+  llvm::ErrorOr<llvm::vfs::Status> S = FS->status(FilePath.c_str());
   if (!S)
     return true;
   Result = *S;

lib/Basic/FileSystemStatCache.cpp

@@ -12,17 +12,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/FileSystemStatCache.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <utility>
 
 using namespace clang;
 
 void FileSystemStatCache::anchor() {}
 
-static void copyStatusToFileData(const vfs::Status &Status,
+static void copyStatusToFileData(const llvm::vfs::Status &Status,
                                  FileData &Data) {
   Data.Name = Status.getName();
   Data.Size = Status.getSize();
@@ -44,8 +44,9 @@ static void copyStatusToFileData(const vfs::Status &Status,
 /// implementation can optionally fill in FileDescriptor with a valid
 /// descriptor and the client guarantees that it will close it.
 bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
-                              std::unique_ptr<vfs::File> *F,
-                              FileSystemStatCache *Cache, vfs::FileSystem &FS) {
+                              std::unique_ptr<llvm::vfs::File> *F,
+                              FileSystemStatCache *Cache,
+                              llvm::vfs::FileSystem &FS) {
   LookupResult R;
   bool isForDir = !isFile;
 
@@ -55,7 +56,7 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
   else if (isForDir || !F) {
     // If this is a directory or a file descriptor is not needed and we have
     // no cache, just go to the file system.
-    llvm::ErrorOr<vfs::Status> Status = FS.status(Path);
+    llvm::ErrorOr<llvm::vfs::Status> Status = FS.status(Path);
     if (!Status) {
       R = CacheMissing;
     } else {
@@ -79,7 +80,7 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
       // 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.
-      llvm::ErrorOr<vfs::Status> Status = (*OwnedFile)->status();
+      llvm::ErrorOr<llvm::vfs::Status> Status = (*OwnedFile)->status();
       if (Status) {
         R = CacheExists;
         copyStatusToFileData(*Status, Data);
@@ -111,7 +112,8 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
 
 MemorizeStatCalls::LookupResult
 MemorizeStatCalls::getStat(StringRef Path, FileData &Data, bool isFile,
-                           std::unique_ptr<vfs::File> *F, vfs::FileSystem &FS) {
+                           std::unique_ptr<llvm::vfs::File> *F,
+                           llvm::vfs::FileSystem &FS) {
   LookupResult Result = statChained(Path, Data, isFile, F, FS);
 
   // Do not cache failed stats, it is easy to construct common inconsistent

lib/Basic/SourceManager.cpp

@@ -2263,8 +2263,8 @@ SourceManagerForFile::SourceManagerForFile(StringRef FileName,
                                            StringRef Content) {
   // This is referenced by `FileMgr` and will be released by `FileMgr` when it
   // is deleted.
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   InMemoryFileSystem->addFile(
       FileName, 0,
       llvm::MemoryBuffer::getMemBuffer(Content, FileName,

lib/Basic/VirtualFileSystem.cpp

@@ -1,2142 +0,0 @@
-//===- VirtualFileSystem.cpp - Virtual File System Layer ------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the VirtualFileSystem interface.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Basic/VirtualFileSystem.h"
-#include "clang/Basic/LLVM.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
-#include "llvm/ADT/None.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/StringSet.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/ADT/iterator_range.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Chrono.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/Errc.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/ErrorOr.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/Path.h"
-#include "llvm/Support/Process.h"
-#include "llvm/Support/SMLoc.h"
-#include "llvm/Support/SourceMgr.h"
-#include "llvm/Support/YAMLParser.h"
-#include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-#include <atomic>
-#include <cassert>
-#include <cstdint>
-#include <iterator>
-#include <limits>
-#include <map>
-#include <memory>
-#include <mutex>
-#include <string>
-#include <system_error>
-#include <utility>
-#include <vector>
-
-using namespace clang;
-using namespace vfs;
-using namespace llvm;
-
-using llvm::sys::fs::file_status;
-using llvm::sys::fs::file_type;
-using llvm::sys::fs::perms;
-using llvm::sys::fs::UniqueID;
-
-Status::Status(const file_status &Status)
-    : UID(Status.getUniqueID()), MTime(Status.getLastModificationTime()),
-      User(Status.getUser()), Group(Status.getGroup()), Size(Status.getSize()),
-      Type(Status.type()), Perms(Status.permissions())  {}
-
-Status::Status(StringRef Name, UniqueID UID, sys::TimePoint<> MTime,
-               uint32_t User, uint32_t Group, uint64_t Size, file_type Type,
-               perms Perms)
-    : Name(Name), UID(UID), MTime(MTime), User(User), Group(Group), Size(Size),
-      Type(Type), Perms(Perms) {}
-
-Status Status::copyWithNewName(const Status &In, StringRef NewName) {
-  return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
-                In.getUser(), In.getGroup(), In.getSize(), In.getType(),
-                In.getPermissions());
-}
-
-Status Status::copyWithNewName(const file_status &In, StringRef NewName) {
-  return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
-                In.getUser(), In.getGroup(), In.getSize(), In.type(),
-                In.permissions());
-}
-
-bool Status::equivalent(const Status &Other) const {
-  assert(isStatusKnown() && Other.isStatusKnown());
-  return getUniqueID() == Other.getUniqueID();
-}
-
-bool Status::isDirectory() const {
-  return Type == file_type::directory_file;
-}
-
-bool Status::isRegularFile() const {
-  return Type == file_type::regular_file;
-}
-
-bool Status::isOther() const {
-  return exists() && !isRegularFile() && !isDirectory() && !isSymlink();
-}
-
-bool Status::isSymlink() const {
-  return Type == file_type::symlink_file;
-}
-
-bool Status::isStatusKnown() const {
-  return Type != file_type::status_error;
-}
-
-bool Status::exists() const {
-  return isStatusKnown() && Type != file_type::file_not_found;
-}
-
-File::~File() = default;
-
-FileSystem::~FileSystem() = default;
-
-ErrorOr<std::unique_ptr<MemoryBuffer>>
-FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
-                             bool RequiresNullTerminator, bool IsVolatile) {
-  auto F = openFileForRead(Name);
-  if (!F)
-    return F.getError();
-
-  return (*F)->getBuffer(Name, FileSize, RequiresNullTerminator, IsVolatile);
-}
-
-std::error_code FileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
-  if (llvm::sys::path::is_absolute(Path))
-    return {};
-
-  auto WorkingDir = getCurrentWorkingDirectory();
-  if (!WorkingDir)
-    return WorkingDir.getError();
-
-  return llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
-}
-
-std::error_code FileSystem::getRealPath(const Twine &Path,
-                                        SmallVectorImpl<char> &Output) const {
-  return errc::operation_not_permitted;
-}
-
-bool FileSystem::exists(const Twine &Path) {
-  auto Status = status(Path);
-  return Status && Status->exists();
-}
-
-#ifndef NDEBUG
-static bool isTraversalComponent(StringRef Component) {
-  return Component.equals("..") || Component.equals(".");
-}
-
-static bool pathHasTraversal(StringRef Path) {
-  using namespace llvm::sys;
-
-  for (StringRef Comp : llvm::make_range(path::begin(Path), path::end(Path)))
-    if (isTraversalComponent(Comp))
-      return true;
-  return false;
-}
-#endif
-
-//===-----------------------------------------------------------------------===/
-// RealFileSystem implementation
-//===-----------------------------------------------------------------------===/
-
-namespace {
-
-/// Wrapper around a raw file descriptor.
-class RealFile : public File {
-  friend class RealFileSystem;
-
-  int FD;
-  Status S;
-  std::string RealName;
-
-  RealFile(int FD, StringRef NewName, StringRef NewRealPathName)
-      : FD(FD), S(NewName, {}, {}, {}, {}, {},
-                  llvm::sys::fs::file_type::status_error, {}),
-        RealName(NewRealPathName.str()) {
-    assert(FD >= 0 && "Invalid or inactive file descriptor");
-  }
-
-public:
-  ~RealFile() override;
-
-  ErrorOr<Status> status() override;
-  ErrorOr<std::string> getName() override;
-  ErrorOr<std::unique_ptr<MemoryBuffer>> getBuffer(const Twine &Name,
-                                                   int64_t FileSize,
-                                                   bool RequiresNullTerminator,
-                                                   bool IsVolatile) override;
-  std::error_code close() override;
-};
-
-} // namespace
-
-RealFile::~RealFile() { close(); }
-
-ErrorOr<Status> RealFile::status() {
-  assert(FD != -1 && "cannot stat closed file");
-  if (!S.isStatusKnown()) {
-    file_status RealStatus;
-    if (std::error_code EC = sys::fs::status(FD, RealStatus))
-      return EC;
-    S = Status::copyWithNewName(RealStatus, S.getName());
-  }
-  return S;
-}
-
-ErrorOr<std::string> RealFile::getName() {
-  return RealName.empty() ? S.getName().str() : RealName;
-}
-
-ErrorOr<std::unique_ptr<MemoryBuffer>>
-RealFile::getBuffer(const Twine &Name, int64_t FileSize,
-                    bool RequiresNullTerminator, bool IsVolatile) {
-  assert(FD != -1 && "cannot get buffer for closed file");
-  return MemoryBuffer::getOpenFile(FD, Name, FileSize, RequiresNullTerminator,
-                                   IsVolatile);
-}
-
-std::error_code RealFile::close() {
-  std::error_code EC = sys::Process::SafelyCloseFileDescriptor(FD);
-  FD = -1;
-  return EC;
-}
-
-namespace {
-
-/// The file system according to your operating system.
-class RealFileSystem : public FileSystem {
-public:
-  ErrorOr<Status> status(const Twine &Path) override;
-  ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
-  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
-
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
-  std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override;
-private:
-  mutable std::mutex CWDMutex;
-  mutable std::string CWDCache;
-};
-
-} // namespace
-
-ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
-  sys::fs::file_status RealStatus;
-  if (std::error_code EC = sys::fs::status(Path, RealStatus))
-    return EC;
-  return Status::copyWithNewName(RealStatus, Path.str());
-}
-
-ErrorOr<std::unique_ptr<File>>
-RealFileSystem::openFileForRead(const Twine &Name) {
-  int FD;
-  SmallString<256> RealName;
-  if (std::error_code EC =
-          sys::fs::openFileForRead(Name, FD, sys::fs::OF_None, &RealName))
-    return EC;
-  return std::unique_ptr<File>(new RealFile(FD, Name.str(), RealName.str()));
-}
-
-llvm::ErrorOr<std::string> RealFileSystem::getCurrentWorkingDirectory() const {
-  std::lock_guard<std::mutex> Lock(CWDMutex);
-  if (!CWDCache.empty())
-    return CWDCache;
-  SmallString<256> Dir;
-  if (std::error_code EC = llvm::sys::fs::current_path(Dir))
-    return EC;
-  CWDCache = Dir.str();
-  return CWDCache;
-}
-
-std::error_code RealFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
-  // FIXME: chdir is thread hostile; on the other hand, creating the same
-  // behavior as chdir is complex: chdir resolves the path once, thus
-  // guaranteeing that all subsequent relative path operations work
-  // on the same path the original chdir resulted in. This makes a
-  // difference for example on network filesystems, where symlinks might be
-  // switched during runtime of the tool. Fixing this depends on having a
-  // file system abstraction that allows openat() style interactions.
-  if (auto EC = llvm::sys::fs::set_current_path(Path))
-    return EC;
-
-  // Invalidate cache.
-  std::lock_guard<std::mutex> Lock(CWDMutex);
-  CWDCache.clear();
-  return std::error_code();
-}
-
-std::error_code
-RealFileSystem::getRealPath(const Twine &Path,
-                            SmallVectorImpl<char> &Output) const {
-  return llvm::sys::fs::real_path(Path, Output);
-}
-
-IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
-  static IntrusiveRefCntPtr<FileSystem> FS = new RealFileSystem();
-  return FS;
-}
-
-namespace {
-
-class RealFSDirIter : public clang::vfs::detail::DirIterImpl {
-  llvm::sys::fs::directory_iterator Iter;
-
-public:
-  RealFSDirIter(const Twine &Path, std::error_code &EC) : Iter(Path, EC) {
-    if (Iter != llvm::sys::fs::directory_iterator())
-      CurrentEntry = directory_entry(Iter->path(), Iter->type());
-  }
-
-  std::error_code increment() override {
-    std::error_code EC;
-    Iter.increment(EC);
-    CurrentEntry = (Iter == llvm::sys::fs::directory_iterator())
-                       ? directory_entry()
-                       : directory_entry(Iter->path(), Iter->type());
-    return EC;
-  }
-};
-
-} // namespace
-
-directory_iterator RealFileSystem::dir_begin(const Twine &Dir,
-                                             std::error_code &EC) {
-  return directory_iterator(std::make_shared<RealFSDirIter>(Dir, EC));
-}
-
-//===-----------------------------------------------------------------------===/
-// OverlayFileSystem implementation
-//===-----------------------------------------------------------------------===/
-
-OverlayFileSystem::OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS) {
-  FSList.push_back(std::move(BaseFS));
-}
-
-void OverlayFileSystem::pushOverlay(IntrusiveRefCntPtr<FileSystem> FS) {
-  FSList.push_back(FS);
-  // Synchronize added file systems by duplicating the working directory from
-  // the first one in the list.
-  FS->setCurrentWorkingDirectory(getCurrentWorkingDirectory().get());
-}
-
-ErrorOr<Status> OverlayFileSystem::status(const Twine &Path) {
-  // FIXME: handle symlinks that cross file systems
-  for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
-    ErrorOr<Status> Status = (*I)->status(Path);
-    if (Status || Status.getError() != llvm::errc::no_such_file_or_directory)
-      return Status;
-  }
-  return make_error_code(llvm::errc::no_such_file_or_directory);
-}
-
-ErrorOr<std::unique_ptr<File>>
-OverlayFileSystem::openFileForRead(const llvm::Twine &Path) {
-  // FIXME: handle symlinks that cross file systems
-  for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
-    auto Result = (*I)->openFileForRead(Path);
-    if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
-      return Result;
-  }
-  return make_error_code(llvm::errc::no_such_file_or_directory);
-}
-
-llvm::ErrorOr<std::string>
-OverlayFileSystem::getCurrentWorkingDirectory() const {
-  // All file systems are synchronized, just take the first working directory.
-  return FSList.front()->getCurrentWorkingDirectory();
-}
-
-std::error_code
-OverlayFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
-  for (auto &FS : FSList)
-    if (std::error_code EC = FS->setCurrentWorkingDirectory(Path))
-      return EC;
-  return {};
-}
-
-std::error_code
-OverlayFileSystem::getRealPath(const Twine &Path,
-                               SmallVectorImpl<char> &Output) const {
-  for (auto &FS : FSList)
-    if (FS->exists(Path))
-      return FS->getRealPath(Path, Output);
-  return errc::no_such_file_or_directory;
-}
-
-clang::vfs::detail::DirIterImpl::~DirIterImpl() = default;
-
-namespace {
-
-class OverlayFSDirIterImpl : public clang::vfs::detail::DirIterImpl {
-  OverlayFileSystem &Overlays;
-  std::string Path;
-  OverlayFileSystem::iterator CurrentFS;
-  directory_iterator CurrentDirIter;
-  llvm::StringSet<> SeenNames;
-
-  std::error_code incrementFS() {
-    assert(CurrentFS != Overlays.overlays_end() && "incrementing past end");
-    ++CurrentFS;
-    for (auto E = Overlays.overlays_end(); CurrentFS != E; ++CurrentFS) {
-      std::error_code EC;
-      CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
-      if (EC && EC != errc::no_such_file_or_directory)
-        return EC;
-      if (CurrentDirIter != directory_iterator())
-        break; // found
-    }
-    return {};
-  }
-
-  std::error_code incrementDirIter(bool IsFirstTime) {
-    assert((IsFirstTime || CurrentDirIter != directory_iterator()) &&
-           "incrementing past end");
-    std::error_code EC;
-    if (!IsFirstTime)
-      CurrentDirIter.increment(EC);
-    if (!EC && CurrentDirIter == directory_iterator())
-      EC = incrementFS();
-    return EC;
-  }
-
-  std::error_code incrementImpl(bool IsFirstTime) {
-    while (true) {
-      std::error_code EC = incrementDirIter(IsFirstTime);
-      if (EC || CurrentDirIter == directory_iterator()) {
-        CurrentEntry = directory_entry();
-        return EC;
-      }
-      CurrentEntry = *CurrentDirIter;
-      StringRef Name = llvm::sys::path::filename(CurrentEntry.path());
-      if (SeenNames.insert(Name).second)
-        return EC; // name not seen before
-    }
-    llvm_unreachable("returned above");
-  }
-
-public:
-  OverlayFSDirIterImpl(const Twine &Path, OverlayFileSystem &FS,
-                       std::error_code &EC)
-      : Overlays(FS), Path(Path.str()), CurrentFS(Overlays.overlays_begin()) {
-    CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
-    EC = incrementImpl(true);
-  }
-
-  std::error_code increment() override { return incrementImpl(false); }
-};
-
-} // namespace
-
-directory_iterator OverlayFileSystem::dir_begin(const Twine &Dir,
-                                                std::error_code &EC) {
-  return directory_iterator(
-      std::make_shared<OverlayFSDirIterImpl>(Dir, *this, EC));
-}
-
-namespace clang {
-namespace vfs {
-
-namespace detail {
-
-enum InMemoryNodeKind { IME_File, IME_Directory, IME_HardLink };
-
-/// The in memory file system is a tree of Nodes. Every node can either be a
-/// file , hardlink or a directory.
-class InMemoryNode {
-  InMemoryNodeKind Kind;
-  std::string FileName;
-
-public:
-  InMemoryNode(llvm::StringRef FileName, InMemoryNodeKind Kind)
-      : Kind(Kind), FileName(llvm::sys::path::filename(FileName)) {}
-  virtual ~InMemoryNode() = default;
-
-  /// Get the filename of this node (the name without the directory part).
-  StringRef getFileName() const { return FileName; }
-  InMemoryNodeKind getKind() const { return Kind; }
-  virtual std::string toString(unsigned Indent) const = 0;
-};
-
-class InMemoryFile : public InMemoryNode {
-  Status Stat;
-  std::unique_ptr<llvm::MemoryBuffer> Buffer;
-
-public:
-  InMemoryFile(Status Stat, std::unique_ptr<llvm::MemoryBuffer> Buffer)
-      : InMemoryNode(Stat.getName(), IME_File), Stat(std::move(Stat)),
-        Buffer(std::move(Buffer)) {}
-
-  /// Return the \p Status for this node. \p RequestedName should be the name
-  /// through which the caller referred to this node. It will override
-  /// \p Status::Name in the return value, to mimic the behavior of \p RealFile.
-  Status getStatus(StringRef RequestedName) const {
-    return Status::copyWithNewName(Stat, RequestedName);
-  }
-  llvm::MemoryBuffer *getBuffer() const { return Buffer.get(); }
-
-  std::string toString(unsigned Indent) const override {
-    return (std::string(Indent, ' ') + Stat.getName() + "\n").str();
-  }
-
-  static bool classof(const InMemoryNode *N) {
-    return N->getKind() == IME_File;
-  }
-};
-
-namespace {
-
-class InMemoryHardLink : public InMemoryNode {
-  const InMemoryFile &ResolvedFile;
-
-public:
-  InMemoryHardLink(StringRef Path, const InMemoryFile &ResolvedFile)
-      : InMemoryNode(Path, IME_HardLink), ResolvedFile(ResolvedFile) {}
-  const InMemoryFile &getResolvedFile() const { return ResolvedFile; }
-
-  std::string toString(unsigned Indent) const override {
-    return std::string(Indent, ' ') + "HardLink to -> " +
-           ResolvedFile.toString(0);
-  }
-
-  static bool classof(const InMemoryNode *N) {
-    return N->getKind() == IME_HardLink;
-  }
-};
-
-/// Adapt a InMemoryFile for VFS' File interface.  The goal is to make
-/// \p InMemoryFileAdaptor mimic as much as possible the behavior of
-/// \p RealFile.
-class InMemoryFileAdaptor : public File {
-  const InMemoryFile &Node;
-  /// The name to use when returning a Status for this file.
-  std::string RequestedName;
-
-public:
-  explicit InMemoryFileAdaptor(const InMemoryFile &Node,
-                               std::string RequestedName)
-      : Node(Node), RequestedName(std::move(RequestedName)) {}
-
-  llvm::ErrorOr<Status> status() override {
-    return Node.getStatus(RequestedName);
-  }
-
-  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
-  getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
-            bool IsVolatile) override {
-    llvm::MemoryBuffer *Buf = Node.getBuffer();
-    return llvm::MemoryBuffer::getMemBuffer(
-        Buf->getBuffer(), Buf->getBufferIdentifier(), RequiresNullTerminator);
-  }
-
-  std::error_code close() override { return {}; }
-};
-} // namespace
-
-class InMemoryDirectory : public InMemoryNode {
-  Status Stat;
-  llvm::StringMap<std::unique_ptr<InMemoryNode>> Entries;
-
-public:
-  InMemoryDirectory(Status Stat)
-      : InMemoryNode(Stat.getName(), IME_Directory), Stat(std::move(Stat)) {}
-
-  /// Return the \p Status for this node. \p RequestedName should be the name
-  /// through which the caller referred to this node. It will override
-  /// \p Status::Name in the return value, to mimic the behavior of \p RealFile.
-  Status getStatus(StringRef RequestedName) const {
-    return Status::copyWithNewName(Stat, RequestedName);
-  }
-  InMemoryNode *getChild(StringRef Name) {
-    auto I = Entries.find(Name);
-    if (I != Entries.end())
-      return I->second.get();
-    return nullptr;
-  }
-
-  InMemoryNode *addChild(StringRef Name, std::unique_ptr<InMemoryNode> Child) {
-    return Entries.insert(make_pair(Name, std::move(Child)))
-        .first->second.get();
-  }
-
-  using const_iterator = decltype(Entries)::const_iterator;
-
-  const_iterator begin() const { return Entries.begin(); }
-  const_iterator end() const { return Entries.end(); }
-
-  std::string toString(unsigned Indent) const override {
-    std::string Result =
-        (std::string(Indent, ' ') + Stat.getName() + "\n").str();
-    for (const auto &Entry : Entries)
-      Result += Entry.second->toString(Indent + 2);
-    return Result;
-  }
-
-  static bool classof(const InMemoryNode *N) {
-    return N->getKind() == IME_Directory;
-  }
-};
-
-namespace {
-Status getNodeStatus(const InMemoryNode *Node, StringRef RequestedName) {
-  if (auto Dir = dyn_cast<detail::InMemoryDirectory>(Node))
-    return Dir->getStatus(RequestedName);
-  if (auto File = dyn_cast<detail::InMemoryFile>(Node))
-    return File->getStatus(RequestedName);
-  if (auto Link = dyn_cast<detail::InMemoryHardLink>(Node))
-    return Link->getResolvedFile().getStatus(RequestedName);
-  llvm_unreachable("Unknown node type");
-}
-} // namespace
-} // namespace detail
-
-InMemoryFileSystem::InMemoryFileSystem(bool UseNormalizedPaths)
-    : Root(new detail::InMemoryDirectory(
-          Status("", getNextVirtualUniqueID(), llvm::sys::TimePoint<>(), 0, 0,
-                 0, llvm::sys::fs::file_type::directory_file,
-                 llvm::sys::fs::perms::all_all))),
-      UseNormalizedPaths(UseNormalizedPaths) {}
-
-InMemoryFileSystem::~InMemoryFileSystem() = default;
-
-std::string InMemoryFileSystem::toString() const {
-  return Root->toString(/*Indent=*/0);
-}
-
-bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
-                                 std::unique_ptr<llvm::MemoryBuffer> Buffer,
-                                 Optional<uint32_t> User,
-                                 Optional<uint32_t> Group,
-                                 Optional<llvm::sys::fs::file_type> Type,
-                                 Optional<llvm::sys::fs::perms> Perms,
-                                 const detail::InMemoryFile *HardLinkTarget) {
-  SmallString<128> Path;
-  P.toVector(Path);
-
-  // Fix up relative paths. This just prepends the current working directory.
-  std::error_code EC = makeAbsolute(Path);
-  assert(!EC);
-  (void)EC;
-
-  if (useNormalizedPaths())
-    llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-
-  if (Path.empty())
-    return false;
-
-  detail::InMemoryDirectory *Dir = Root.get();
-  auto I = llvm::sys::path::begin(Path), E = sys::path::end(Path);
-  const auto ResolvedUser = User.getValueOr(0);
-  const auto ResolvedGroup = Group.getValueOr(0);
-  const auto ResolvedType = Type.getValueOr(sys::fs::file_type::regular_file);
-  const auto ResolvedPerms = Perms.getValueOr(sys::fs::all_all);
-  assert(!(HardLinkTarget && Buffer) && "HardLink cannot have a buffer");
-  // Any intermediate directories we create should be accessible by
-  // the owner, even if Perms says otherwise for the final path.
-  const auto NewDirectoryPerms = ResolvedPerms | sys::fs::owner_all;
-  while (true) {
-    StringRef Name = *I;
-    detail::InMemoryNode *Node = Dir->getChild(Name);
-    ++I;
-    if (!Node) {
-      if (I == E) {
-        // End of the path.
-        std::unique_ptr<detail::InMemoryNode> Child;
-        if (HardLinkTarget)
-          Child.reset(new detail::InMemoryHardLink(P.str(), *HardLinkTarget));
-        else {
-          // Create a new file or directory.
-          Status Stat(P.str(), getNextVirtualUniqueID(),
-                      llvm::sys::toTimePoint(ModificationTime), ResolvedUser,
-                      ResolvedGroup, Buffer->getBufferSize(), ResolvedType,
-                      ResolvedPerms);
-          if (ResolvedType == sys::fs::file_type::directory_file) {
-            Child.reset(new detail::InMemoryDirectory(std::move(Stat)));
-          } else {
-            Child.reset(
-                new detail::InMemoryFile(std::move(Stat), std::move(Buffer)));
-          }
-        }
-        Dir->addChild(Name, std::move(Child));
-        return true;
-      }
-
-      // Create a new directory. Use the path up to here.
-      Status Stat(
-          StringRef(Path.str().begin(), Name.end() - Path.str().begin()),
-          getNextVirtualUniqueID(), llvm::sys::toTimePoint(ModificationTime),
-          ResolvedUser, ResolvedGroup, 0, sys::fs::file_type::directory_file,
-          NewDirectoryPerms);
-      Dir = cast<detail::InMemoryDirectory>(Dir->addChild(
-          Name, llvm::make_unique<detail::InMemoryDirectory>(std::move(Stat))));
-      continue;
-    }
-
-    if (auto *NewDir = dyn_cast<detail::InMemoryDirectory>(Node)) {
-      Dir = NewDir;
-    } else {
-      assert((isa<detail::InMemoryFile>(Node) ||
-              isa<detail::InMemoryHardLink>(Node)) &&
-             "Must be either file, hardlink or directory!");
-
-      // Trying to insert a directory in place of a file.
-      if (I != E)
-        return false;
-
-      // Return false only if the new file is different from the existing one.
-      if (auto Link = dyn_cast<detail::InMemoryHardLink>(Node)) {
-        return Link->getResolvedFile().getBuffer()->getBuffer() ==
-               Buffer->getBuffer();
-      }
-      return cast<detail::InMemoryFile>(Node)->getBuffer()->getBuffer() ==
-             Buffer->getBuffer();
-    }
-  }
-}
-
-bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
-                                 std::unique_ptr<llvm::MemoryBuffer> Buffer,
-                                 Optional<uint32_t> User,
-                                 Optional<uint32_t> Group,
-                                 Optional<llvm::sys::fs::file_type> Type,
-                                 Optional<llvm::sys::fs::perms> Perms) {
-  return addFile(P, ModificationTime, std::move(Buffer), User, Group, Type,
-                 Perms, /*HardLinkTarget=*/nullptr);
-}
-
-bool InMemoryFileSystem::addFileNoOwn(const Twine &P, time_t ModificationTime,
-                                      llvm::MemoryBuffer *Buffer,
-                                      Optional<uint32_t> User,
-                                      Optional<uint32_t> Group,
-                                      Optional<llvm::sys::fs::file_type> Type,
-                                      Optional<llvm::sys::fs::perms> Perms) {
-  return addFile(P, ModificationTime,
-                 llvm::MemoryBuffer::getMemBuffer(
-                     Buffer->getBuffer(), Buffer->getBufferIdentifier()),
-                 std::move(User), std::move(Group), std::move(Type),
-                 std::move(Perms));
-}
-
-static ErrorOr<const detail::InMemoryNode *>
-lookupInMemoryNode(const InMemoryFileSystem &FS, detail::InMemoryDirectory *Dir,
-                   const Twine &P) {
-  SmallString<128> Path;
-  P.toVector(Path);
-
-  // Fix up relative paths. This just prepends the current working directory.
-  std::error_code EC = FS.makeAbsolute(Path);
-  assert(!EC);
-  (void)EC;
-
-  if (FS.useNormalizedPaths())
-    llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-
-  if (Path.empty())
-    return Dir;
-
-  auto I = llvm::sys::path::begin(Path), E = llvm::sys::path::end(Path);
-  while (true) {
-    detail::InMemoryNode *Node = Dir->getChild(*I);
-    ++I;
-    if (!Node)
-      return errc::no_such_file_or_directory;
-
-    // Return the file if it's at the end of the path.
-    if (auto File = dyn_cast<detail::InMemoryFile>(Node)) {
-      if (I == E)
-        return File;
-      return errc::no_such_file_or_directory;
-    }
-
-    // If Node is HardLink then return the resolved file.
-    if (auto File = dyn_cast<detail::InMemoryHardLink>(Node)) {
-      if (I == E)
-        return &File->getResolvedFile();
-      return errc::no_such_file_or_directory;
-    }
-    // Traverse directories.
-    Dir = cast<detail::InMemoryDirectory>(Node);
-    if (I == E)
-      return Dir;
-  }
-}
-
-bool InMemoryFileSystem::addHardLink(const Twine &FromPath,
-                                     const Twine &ToPath) {
-  auto FromNode = lookupInMemoryNode(*this, Root.get(), FromPath);
-  auto ToNode = lookupInMemoryNode(*this, Root.get(), ToPath);
-  // FromPath must not have been added before. ToPath must have been added
-  // before. Resolved ToPath must be a File.
-  if (!ToNode || FromNode || !isa<detail::InMemoryFile>(*ToNode))
-    return false;
-  return this->addFile(FromPath, 0, nullptr, None, None, None, None,
-                       cast<detail::InMemoryFile>(*ToNode));
-}
-
-llvm::ErrorOr<Status> InMemoryFileSystem::status(const Twine &Path) {
-  auto Node = lookupInMemoryNode(*this, Root.get(), Path);
-  if (Node)
-    return detail::getNodeStatus(*Node, Path.str());
-  return Node.getError();
-}
-
-llvm::ErrorOr<std::unique_ptr<File>>
-InMemoryFileSystem::openFileForRead(const Twine &Path) {
-  auto Node = lookupInMemoryNode(*this, Root.get(), Path);
-  if (!Node)
-    return Node.getError();
-
-  // When we have a file provide a heap-allocated wrapper for the memory buffer
-  // to match the ownership semantics for File.
-  if (auto *F = dyn_cast<detail::InMemoryFile>(*Node))
-    return std::unique_ptr<File>(
-        new detail::InMemoryFileAdaptor(*F, Path.str()));
-
-  // FIXME: errc::not_a_file?
-  return make_error_code(llvm::errc::invalid_argument);
-}
-
-namespace {
-
-/// Adaptor from InMemoryDir::iterator to directory_iterator.
-class InMemoryDirIterator : public clang::vfs::detail::DirIterImpl {
-  detail::InMemoryDirectory::const_iterator I;
-  detail::InMemoryDirectory::const_iterator E;
-  std::string RequestedDirName;
-
-  void setCurrentEntry() {
-    if (I != E) {
-      SmallString<256> Path(RequestedDirName);
-      llvm::sys::path::append(Path, I->second->getFileName());
-      sys::fs::file_type Type;
-      switch (I->second->getKind()) {
-        case detail::IME_File:
-        case detail::IME_HardLink:
-          Type = sys::fs::file_type::regular_file;
-          break;
-        case detail::IME_Directory:
-          Type = sys::fs::file_type::directory_file;
-          break;
-      }
-      CurrentEntry = directory_entry(Path.str(), Type);
-    } else {
-      // When we're at the end, make CurrentEntry invalid and DirIterImpl will
-      // do the rest.
-      CurrentEntry = directory_entry();
-    }
-  }
-
-public:
-  InMemoryDirIterator() = default;
-
-  explicit InMemoryDirIterator(const detail::InMemoryDirectory &Dir,
-                               std::string RequestedDirName)
-      : I(Dir.begin()), E(Dir.end()),
-        RequestedDirName(std::move(RequestedDirName)) {
-    setCurrentEntry();
-  }
-
-  std::error_code increment() override {
-    ++I;
-    setCurrentEntry();
-    return {};
-  }
-};
-
-} // namespace
-
-directory_iterator InMemoryFileSystem::dir_begin(const Twine &Dir,
-                                                 std::error_code &EC) {
-  auto Node = lookupInMemoryNode(*this, Root.get(), Dir);
-  if (!Node) {
-    EC = Node.getError();
-    return directory_iterator(std::make_shared<InMemoryDirIterator>());
-  }
-
-  if (auto *DirNode = dyn_cast<detail::InMemoryDirectory>(*Node))
-    return directory_iterator(
-        std::make_shared<InMemoryDirIterator>(*DirNode, Dir.str()));
-
-  EC = make_error_code(llvm::errc::not_a_directory);
-  return directory_iterator(std::make_shared<InMemoryDirIterator>());
-}
-
-std::error_code InMemoryFileSystem::setCurrentWorkingDirectory(const Twine &P) {
-  SmallString<128> Path;
-  P.toVector(Path);
-
-  // Fix up relative paths. This just prepends the current working directory.
-  std::error_code EC = makeAbsolute(Path);
-  assert(!EC);
-  (void)EC;
-
-  if (useNormalizedPaths())
-    llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-
-  if (!Path.empty())
-    WorkingDirectory = Path.str();
-  return {};
-}
-
-std::error_code
-InMemoryFileSystem::getRealPath(const Twine &Path,
-                                SmallVectorImpl<char> &Output) const {
-  auto CWD = getCurrentWorkingDirectory();
-  if (!CWD || CWD->empty())
-    return errc::operation_not_permitted;
-  Path.toVector(Output);
-  if (auto EC = makeAbsolute(Output))
-    return EC;
-  llvm::sys::path::remove_dots(Output, /*remove_dot_dot=*/true);
-  return {};
-}
-
-} // namespace vfs
-} // namespace clang
-
-//===-----------------------------------------------------------------------===/
-// RedirectingFileSystem implementation
-//===-----------------------------------------------------------------------===/
-
-namespace {
-
-enum EntryKind {
-  EK_Directory,
-  EK_File
-};
-
-/// A single file or directory in the VFS.
-class Entry {
-  EntryKind Kind;
-  std::string Name;
-
-public:
-  Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {}
-  virtual ~Entry() = default;
-
-  StringRef getName() const { return Name; }
-  EntryKind getKind() const { return Kind; }
-};
-
-class RedirectingDirectoryEntry : public Entry {
-  std::vector<std::unique_ptr<Entry>> Contents;
-  Status S;
-
-public:
-  RedirectingDirectoryEntry(StringRef Name,
-                            std::vector<std::unique_ptr<Entry>> Contents,
-                            Status S)
-      : Entry(EK_Directory, Name), Contents(std::move(Contents)),
-        S(std::move(S)) {}
-  RedirectingDirectoryEntry(StringRef Name, Status S)
-      : Entry(EK_Directory, Name), S(std::move(S)) {}
-
-  Status getStatus() { return S; }
-
-  void addContent(std::unique_ptr<Entry> Content) {
-    Contents.push_back(std::move(Content));
-  }
-
-  Entry *getLastContent() const { return Contents.back().get(); }
-
-  using iterator = decltype(Contents)::iterator;
-
-  iterator contents_begin() { return Contents.begin(); }
-  iterator contents_end() { return Contents.end(); }
-
-  static bool classof(const Entry *E) { return E->getKind() == EK_Directory; }
-};
-
-class RedirectingFileEntry : public Entry {
-public:
-  enum NameKind {
-    NK_NotSet,
-    NK_External,
-    NK_Virtual
-  };
-
-private:
-  std::string ExternalContentsPath;
-  NameKind UseName;
-
-public:
-  RedirectingFileEntry(StringRef Name, StringRef ExternalContentsPath,
-                       NameKind UseName)
-      : Entry(EK_File, Name), ExternalContentsPath(ExternalContentsPath),
-        UseName(UseName) {}
-
-  StringRef getExternalContentsPath() const { return ExternalContentsPath; }
-
-  /// whether to use the external path as the name for this file.
-  bool useExternalName(bool GlobalUseExternalName) const {
-    return UseName == NK_NotSet ? GlobalUseExternalName
-                                : (UseName == NK_External);
-  }
-
-  NameKind getUseName() const { return UseName; }
-
-  static bool classof(const Entry *E) { return E->getKind() == EK_File; }
-};
-
-class VFSFromYamlDirIterImpl : public clang::vfs::detail::DirIterImpl {
-  std::string Dir;
-  RedirectingDirectoryEntry::iterator Current, End;
-
-  std::error_code incrementImpl();
-
-public:
-  VFSFromYamlDirIterImpl(const Twine &Path,
-                         RedirectingDirectoryEntry::iterator Begin,
-                         RedirectingDirectoryEntry::iterator End,
-                         std::error_code &EC);
-
-  std::error_code increment() override;
-};
-
-/// A virtual file system parsed from a YAML file.
-///
-/// Currently, this class allows creating virtual directories and mapping
-/// virtual file paths to existing external files, available in \c ExternalFS.
-///
-/// The basic structure of the parsed file is:
-/// \verbatim
-/// {
-///   'version': <version number>,
-///   <optional configuration>
-///   'roots': [
-///              <directory entries>
-///            ]
-/// }
-/// \endverbatim
-///
-/// All configuration options are optional.
-///   'case-sensitive': <boolean, default=true>
-///   'use-external-names': <boolean, default=true>
-///   'overlay-relative': <boolean, default=false>
-///   'ignore-non-existent-contents': <boolean, default=true>
-///
-/// Virtual directories are represented as
-/// \verbatim
-/// {
-///   'type': 'directory',
-///   'name': <string>,
-///   'contents': [ <file or directory entries> ]
-/// }
-/// \endverbatim
-///
-/// The default attributes for virtual directories are:
-/// \verbatim
-/// MTime = now() when created
-/// Perms = 0777
-/// User = Group = 0
-/// Size = 0
-/// UniqueID = unspecified unique value
-/// \endverbatim
-///
-/// Re-mapped files are represented as
-/// \verbatim
-/// {
-///   'type': 'file',
-///   'name': <string>,
-///   'use-external-name': <boolean> # Optional
-///   'external-contents': <path to external file>
-/// }
-/// \endverbatim
-///
-/// and inherit their attributes from the external contents.
-///
-/// In both cases, the 'name' field may contain multiple path components (e.g.
-/// /path/to/file). However, any directory that contains more than one child
-/// must be uniquely represented by a directory entry.
-class RedirectingFileSystem : public vfs::FileSystem {
-  friend class RedirectingFileSystemParser;
-
-  /// The root(s) of the virtual file system.
-  std::vector<std::unique_ptr<Entry>> Roots;
-
-  /// The file system to use for external references.
-  IntrusiveRefCntPtr<FileSystem> ExternalFS;
-
-  /// If IsRelativeOverlay is set, this represents the directory
-  /// path that should be prefixed to each 'external-contents' entry
-  /// when reading from YAML files.
-  std::string ExternalContentsPrefixDir;
-
-  /// @name Configuration
-  /// @{
-
-  /// Whether to perform case-sensitive comparisons.
-  ///
-  /// Currently, case-insensitive matching only works correctly with ASCII.
-  bool CaseSensitive = true;
-
-  /// IsRelativeOverlay marks whether a ExternalContentsPrefixDir path must
-  /// be prefixed in every 'external-contents' when reading from YAML files.
-  bool IsRelativeOverlay = false;
-
-  /// Whether to use to use the value of 'external-contents' for the
-  /// names of files.  This global value is overridable on a per-file basis.
-  bool UseExternalNames = true;
-
-  /// Whether an invalid path obtained via 'external-contents' should
-  /// cause iteration on the VFS to stop. If 'true', the VFS should ignore
-  /// the entry and continue with the next. Allows YAML files to be shared
-  /// across multiple compiler invocations regardless of prior existent
-  /// paths in 'external-contents'. This global value is overridable on a
-  /// per-file basis.
-  bool IgnoreNonExistentContents = true;
-  /// @}
-
-  /// Virtual file paths and external files could be canonicalized without "..",
-  /// "." and "./" in their paths. FIXME: some unittests currently fail on
-  /// win32 when using remove_dots and remove_leading_dotslash on paths.
-  bool UseCanonicalizedPaths =
-#ifdef _WIN32
-      false;
-#else
-      true;
-#endif
-
-private:
-  RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS)
-      : ExternalFS(std::move(ExternalFS)) {}
-
-  /// Looks up the path <tt>[Start, End)</tt> in \p From, possibly
-  /// recursing into the contents of \p From if it is a directory.
-  ErrorOr<Entry *> lookupPath(sys::path::const_iterator Start,
-                              sys::path::const_iterator End, Entry *From);
-
-  /// Get the status of a given an \c Entry.
-  ErrorOr<Status> status(const Twine &Path, Entry *E);
-
-public:
-  /// Looks up \p Path in \c Roots.
-  ErrorOr<Entry *> lookupPath(const Twine &Path);
-
-  /// Parses \p Buffer, which is expected to be in YAML format and
-  /// returns a virtual file system representing its contents.
-  static RedirectingFileSystem *
-  create(std::unique_ptr<MemoryBuffer> Buffer,
-         SourceMgr::DiagHandlerTy DiagHandler, StringRef YAMLFilePath,
-         void *DiagContext, IntrusiveRefCntPtr<FileSystem> ExternalFS);
-
-  ErrorOr<Status> status(const Twine &Path) override;
-  ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
-
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
-    return ExternalFS->getCurrentWorkingDirectory();
-  }
-
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
-    return ExternalFS->setCurrentWorkingDirectory(Path);
-  }
-
-  directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override{
-    ErrorOr<Entry *> E = lookupPath(Dir);
-    if (!E) {
-      EC = E.getError();
-      return {};
-    }
-    ErrorOr<Status> S = status(Dir, *E);
-    if (!S) {
-      EC = S.getError();
-      return {};
-    }
-    if (!S->isDirectory()) {
-      EC = std::error_code(static_cast<int>(errc::not_a_directory),
-                           std::system_category());
-      return {};
-    }
-
-    auto *D = cast<RedirectingDirectoryEntry>(*E);
-    return directory_iterator(std::make_shared<VFSFromYamlDirIterImpl>(
-        Dir, D->contents_begin(), D->contents_end(), EC));
-  }
-
-  void setExternalContentsPrefixDir(StringRef PrefixDir) {
-    ExternalContentsPrefixDir = PrefixDir.str();
-  }
-
-  StringRef getExternalContentsPrefixDir() const {
-    return ExternalContentsPrefixDir;
-  }
-
-  bool ignoreNonExistentContents() const {
-    return IgnoreNonExistentContents;
-  }
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void dump() const {
-    for (const auto &Root : Roots)
-      dumpEntry(Root.get());
-  }
-
-LLVM_DUMP_METHOD void dumpEntry(Entry *E, int NumSpaces = 0) const {
-    StringRef Name = E->getName();
-    for (int i = 0, e = NumSpaces; i < e; ++i)
-      dbgs() << " ";
-    dbgs() << "'" << Name.str().c_str() << "'" << "\n";
-
-    if (E->getKind() == EK_Directory) {
-      auto *DE = dyn_cast<RedirectingDirectoryEntry>(E);
-      assert(DE && "Should be a directory");
-
-      for (std::unique_ptr<Entry> &SubEntry :
-           llvm::make_range(DE->contents_begin(), DE->contents_end()))
-        dumpEntry(SubEntry.get(), NumSpaces+2);
-    }
-  }
-#endif
-};
-
-/// A helper class to hold the common YAML parsing state.
-class RedirectingFileSystemParser {
-  yaml::Stream &Stream;
-
-  void error(yaml::Node *N, const Twine &Msg) {
-    Stream.printError(N, Msg);
-  }
-
-  // false on error
-  bool parseScalarString(yaml::Node *N, StringRef &Result,
-                         SmallVectorImpl<char> &Storage) {
-    const auto *S = dyn_cast<yaml::ScalarNode>(N);
-
-    if (!S) {
-      error(N, "expected string");
-      return false;
-    }
-    Result = S->getValue(Storage);
-    return true;
-  }
-
-  // false on error
-  bool parseScalarBool(yaml::Node *N, bool &Result) {
-    SmallString<5> Storage;
-    StringRef Value;
-    if (!parseScalarString(N, Value, Storage))
-      return false;
-
-    if (Value.equals_lower("true") || Value.equals_lower("on") ||
-        Value.equals_lower("yes") || Value == "1") {
-      Result = true;
-      return true;
-    } else if (Value.equals_lower("false") || Value.equals_lower("off") ||
-               Value.equals_lower("no") || Value == "0") {
-      Result = false;
-      return true;
-    }
-
-    error(N, "expected boolean value");
-    return false;
-  }
-
-  struct KeyStatus {
-    bool Required;
-    bool Seen = false;
-
-    KeyStatus(bool Required = false) : Required(Required) {}
-  };
-
-  using KeyStatusPair = std::pair<StringRef, KeyStatus>;
-
-  // false on error
-  bool checkDuplicateOrUnknownKey(yaml::Node *KeyNode, StringRef Key,
-                                  DenseMap<StringRef, KeyStatus> &Keys) {
-    if (!Keys.count(Key)) {
-      error(KeyNode, "unknown key");
-      return false;
-    }
-    KeyStatus &S = Keys[Key];
-    if (S.Seen) {
-      error(KeyNode, Twine("duplicate key '") + Key + "'");
-      return false;
-    }
-    S.Seen = true;
-    return true;
-  }
-
-  // false on error
-  bool checkMissingKeys(yaml::Node *Obj, DenseMap<StringRef, KeyStatus> &Keys) {
-    for (const auto &I : Keys) {
-      if (I.second.Required && !I.second.Seen) {
-        error(Obj, Twine("missing key '") + I.first + "'");
-        return false;
-      }
-    }
-    return true;
-  }
-
-  Entry *lookupOrCreateEntry(RedirectingFileSystem *FS, StringRef Name,
-                             Entry *ParentEntry = nullptr) {
-    if (!ParentEntry) { // Look for a existent root
-      for (const auto &Root : FS->Roots) {
-        if (Name.equals(Root->getName())) {
-          ParentEntry = Root.get();
-          return ParentEntry;
-        }
-      }
-    } else { // Advance to the next component
-      auto *DE = dyn_cast<RedirectingDirectoryEntry>(ParentEntry);
-      for (std::unique_ptr<Entry> &Content :
-           llvm::make_range(DE->contents_begin(), DE->contents_end())) {
-        auto *DirContent = dyn_cast<RedirectingDirectoryEntry>(Content.get());
-        if (DirContent && Name.equals(Content->getName()))
-          return DirContent;
-      }
-    }
-
-    // ... or create a new one
-    std::unique_ptr<Entry> E = llvm::make_unique<RedirectingDirectoryEntry>(
-        Name,
-        Status("", getNextVirtualUniqueID(), std::chrono::system_clock::now(),
-               0, 0, 0, file_type::directory_file, sys::fs::all_all));
-
-    if (!ParentEntry) { // Add a new root to the overlay
-      FS->Roots.push_back(std::move(E));
-      ParentEntry = FS->Roots.back().get();
-      return ParentEntry;
-    }
-
-    auto *DE = dyn_cast<RedirectingDirectoryEntry>(ParentEntry);
-    DE->addContent(std::move(E));
-    return DE->getLastContent();
-  }
-
-  void uniqueOverlayTree(RedirectingFileSystem *FS, Entry *SrcE,
-                         Entry *NewParentE = nullptr) {
-    StringRef Name = SrcE->getName();
-    switch (SrcE->getKind()) {
-    case EK_Directory: {
-      auto *DE = dyn_cast<RedirectingDirectoryEntry>(SrcE);
-      assert(DE && "Must be a directory");
-      // Empty directories could be present in the YAML as a way to
-      // describe a file for a current directory after some of its subdir
-      // is parsed. This only leads to redundant walks, ignore it.
-      if (!Name.empty())
-        NewParentE = lookupOrCreateEntry(FS, Name, NewParentE);
-      for (std::unique_ptr<Entry> &SubEntry :
-           llvm::make_range(DE->contents_begin(), DE->contents_end()))
-        uniqueOverlayTree(FS, SubEntry.get(), NewParentE);
-      break;
-    }
-    case EK_File: {
-      auto *FE = dyn_cast<RedirectingFileEntry>(SrcE);
-      assert(FE && "Must be a file");
-      assert(NewParentE && "Parent entry must exist");
-      auto *DE = dyn_cast<RedirectingDirectoryEntry>(NewParentE);
-      DE->addContent(llvm::make_unique<RedirectingFileEntry>(
-          Name, FE->getExternalContentsPath(), FE->getUseName()));
-      break;
-    }
-    }
-  }
-
-  std::unique_ptr<Entry> parseEntry(yaml::Node *N, RedirectingFileSystem *FS,
-                                    bool IsRootEntry) {
-    auto *M = dyn_cast<yaml::MappingNode>(N);
-    if (!M) {
-      error(N, "expected mapping node for file or directory entry");
-      return nullptr;
-    }
-
-    KeyStatusPair Fields[] = {
-      KeyStatusPair("name", true),
-      KeyStatusPair("type", true),
-      KeyStatusPair("contents", false),
-      KeyStatusPair("external-contents", false),
-      KeyStatusPair("use-external-name", false),
-    };
-
-    DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));
-
-    bool HasContents = false; // external or otherwise
-    std::vector<std::unique_ptr<Entry>> EntryArrayContents;
-    std::string ExternalContentsPath;
-    std::string Name;
-    yaml::Node *NameValueNode;
-    auto UseExternalName = RedirectingFileEntry::NK_NotSet;
-    EntryKind Kind;
-
-    for (auto &I : *M) {
-      StringRef Key;
-      // Reuse the buffer for key and value, since we don't look at key after
-      // parsing value.
-      SmallString<256> Buffer;
-      if (!parseScalarString(I.getKey(), Key, Buffer))
-        return nullptr;
-
-      if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
-        return nullptr;
-
-      StringRef Value;
-      if (Key == "name") {
-        if (!parseScalarString(I.getValue(), Value, Buffer))
-          return nullptr;
-
-        NameValueNode = I.getValue();
-        if (FS->UseCanonicalizedPaths) {
-          SmallString<256> Path(Value);
-          // Guarantee that old YAML files containing paths with ".." and "."
-          // are properly canonicalized before read into the VFS.
-          Path = sys::path::remove_leading_dotslash(Path);
-          sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-          Name = Path.str();
-        } else {
-          Name = Value;
-        }
-      } else if (Key == "type") {
-        if (!parseScalarString(I.getValue(), Value, Buffer))
-          return nullptr;
-        if (Value == "file")
-          Kind = EK_File;
-        else if (Value == "directory")
-          Kind = EK_Directory;
-        else {
-          error(I.getValue(), "unknown value for 'type'");
-          return nullptr;
-        }
-      } else if (Key == "contents") {
-        if (HasContents) {
-          error(I.getKey(),
-                "entry already has 'contents' or 'external-contents'");
-          return nullptr;
-        }
-        HasContents = true;
-        auto *Contents = dyn_cast<yaml::SequenceNode>(I.getValue());
-        if (!Contents) {
-          // FIXME: this is only for directories, what about files?
-          error(I.getValue(), "expected array");
-          return nullptr;
-        }
-
-        for (auto &I : *Contents) {
-          if (std::unique_ptr<Entry> E =
-                  parseEntry(&I, FS, /*IsRootEntry*/ false))
-            EntryArrayContents.push_back(std::move(E));
-          else
-            return nullptr;
-        }
-      } else if (Key == "external-contents") {
-        if (HasContents) {
-          error(I.getKey(),
-                "entry already has 'contents' or 'external-contents'");
-          return nullptr;
-        }
-        HasContents = true;
-        if (!parseScalarString(I.getValue(), Value, Buffer))
-          return nullptr;
-
-        SmallString<256> FullPath;
-        if (FS->IsRelativeOverlay) {
-          FullPath = FS->getExternalContentsPrefixDir();
-          assert(!FullPath.empty() &&
-                 "External contents prefix directory must exist");
-          llvm::sys::path::append(FullPath, Value);
-        } else {
-          FullPath = Value;
-        }
-
-        if (FS->UseCanonicalizedPaths) {
-          // Guarantee that old YAML files containing paths with ".." and "."
-          // are properly canonicalized before read into the VFS.
-          FullPath = sys::path::remove_leading_dotslash(FullPath);
-          sys::path::remove_dots(FullPath, /*remove_dot_dot=*/true);
-        }
-        ExternalContentsPath = FullPath.str();
-      } else if (Key == "use-external-name") {
-        bool Val;
-        if (!parseScalarBool(I.getValue(), Val))
-          return nullptr;
-        UseExternalName = Val ? RedirectingFileEntry::NK_External
-                              : RedirectingFileEntry::NK_Virtual;
-      } else {
-        llvm_unreachable("key missing from Keys");
-      }
-    }
-
-    if (Stream.failed())
-      return nullptr;
-
-    // check for missing keys
-    if (!HasContents) {
-      error(N, "missing key 'contents' or 'external-contents'");
-      return nullptr;
-    }
-    if (!checkMissingKeys(N, Keys))
-      return nullptr;
-
-    // check invalid configuration
-    if (Kind == EK_Directory &&
-        UseExternalName != RedirectingFileEntry::NK_NotSet) {
-      error(N, "'use-external-name' is not supported for directories");
-      return nullptr;
-    }
-
-    if (IsRootEntry && !sys::path::is_absolute(Name)) {
-      assert(NameValueNode && "Name presence should be checked earlier");
-      error(NameValueNode,
-            "entry with relative path at the root level is not discoverable");
-      return nullptr;
-    }
-
-    // Remove trailing slash(es), being careful not to remove the root path
-    StringRef Trimmed(Name);
-    size_t RootPathLen = sys::path::root_path(Trimmed).size();
-    while (Trimmed.size() > RootPathLen &&
-           sys::path::is_separator(Trimmed.back()))
-      Trimmed = Trimmed.slice(0, Trimmed.size()-1);
-    // Get the last component
-    StringRef LastComponent = sys::path::filename(Trimmed);
-
-    std::unique_ptr<Entry> Result;
-    switch (Kind) {
-    case EK_File:
-      Result = llvm::make_unique<RedirectingFileEntry>(
-          LastComponent, std::move(ExternalContentsPath), UseExternalName);
-      break;
-    case EK_Directory:
-      Result = llvm::make_unique<RedirectingDirectoryEntry>(
-          LastComponent, std::move(EntryArrayContents),
-          Status("", getNextVirtualUniqueID(), std::chrono::system_clock::now(),
-                 0, 0, 0, file_type::directory_file, sys::fs::all_all));
-      break;
-    }
-
-    StringRef Parent = sys::path::parent_path(Trimmed);
-    if (Parent.empty())
-      return Result;
-
-    // if 'name' contains multiple components, create implicit directory entries
-    for (sys::path::reverse_iterator I = sys::path::rbegin(Parent),
-                                     E = sys::path::rend(Parent);
-         I != E; ++I) {
-      std::vector<std::unique_ptr<Entry>> Entries;
-      Entries.push_back(std::move(Result));
-      Result = llvm::make_unique<RedirectingDirectoryEntry>(
-          *I, std::move(Entries),
-          Status("", getNextVirtualUniqueID(), std::chrono::system_clock::now(),
-                 0, 0, 0, file_type::directory_file, sys::fs::all_all));
-    }
-    return Result;
-  }
-
-public:
-  RedirectingFileSystemParser(yaml::Stream &S) : Stream(S) {}
-
-  // false on error
-  bool parse(yaml::Node *Root, RedirectingFileSystem *FS) {
-    auto *Top = dyn_cast<yaml::MappingNode>(Root);
-    if (!Top) {
-      error(Root, "expected mapping node");
-      return false;
-    }
-
-    KeyStatusPair Fields[] = {
-      KeyStatusPair("version", true),
-      KeyStatusPair("case-sensitive", false),
-      KeyStatusPair("use-external-names", false),
-      KeyStatusPair("overlay-relative", false),
-      KeyStatusPair("ignore-non-existent-contents", false),
-      KeyStatusPair("roots", true),
-    };
-
-    DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));
-    std::vector<std::unique_ptr<Entry>> RootEntries;
-
-    // Parse configuration and 'roots'
-    for (auto &I : *Top) {
-      SmallString<10> KeyBuffer;
-      StringRef Key;
-      if (!parseScalarString(I.getKey(), Key, KeyBuffer))
-        return false;
-
-      if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
-        return false;
-
-      if (Key == "roots") {
-        auto *Roots = dyn_cast<yaml::SequenceNode>(I.getValue());
-        if (!Roots) {
-          error(I.getValue(), "expected array");
-          return false;
-        }
-
-        for (auto &I : *Roots) {
-          if (std::unique_ptr<Entry> E =
-                  parseEntry(&I, FS, /*IsRootEntry*/ true))
-            RootEntries.push_back(std::move(E));
-          else
-            return false;
-        }
-      } else if (Key == "version") {
-        StringRef VersionString;
-        SmallString<4> Storage;
-        if (!parseScalarString(I.getValue(), VersionString, Storage))
-          return false;
-        int Version;
-        if (VersionString.getAsInteger<int>(10, Version)) {
-          error(I.getValue(), "expected integer");
-          return false;
-        }
-        if (Version < 0) {
-          error(I.getValue(), "invalid version number");
-          return false;
-        }
-        if (Version != 0) {
-          error(I.getValue(), "version mismatch, expected 0");
-          return false;
-        }
-      } else if (Key == "case-sensitive") {
-        if (!parseScalarBool(I.getValue(), FS->CaseSensitive))
-          return false;
-      } else if (Key == "overlay-relative") {
-        if (!parseScalarBool(I.getValue(), FS->IsRelativeOverlay))
-          return false;
-      } else if (Key == "use-external-names") {
-        if (!parseScalarBool(I.getValue(), FS->UseExternalNames))
-          return false;
-      } else if (Key == "ignore-non-existent-contents") {
-        if (!parseScalarBool(I.getValue(), FS->IgnoreNonExistentContents))
-          return false;
-      } else {
-        llvm_unreachable("key missing from Keys");
-      }
-    }
-
-    if (Stream.failed())
-      return false;
-
-    if (!checkMissingKeys(Top, Keys))
-      return false;
-
-    // Now that we sucessefully parsed the YAML file, canonicalize the internal
-    // representation to a proper directory tree so that we can search faster
-    // inside the VFS.
-    for (auto &E : RootEntries)
-      uniqueOverlayTree(FS, E.get());
-
-    return true;
-  }
-};
-
-} // namespace
-
-RedirectingFileSystem *
-RedirectingFileSystem::create(std::unique_ptr<MemoryBuffer> Buffer,
-                              SourceMgr::DiagHandlerTy DiagHandler,
-                              StringRef YAMLFilePath, void *DiagContext,
-                              IntrusiveRefCntPtr<FileSystem> ExternalFS) {
-  SourceMgr SM;
-  yaml::Stream Stream(Buffer->getMemBufferRef(), SM);
-
-  SM.setDiagHandler(DiagHandler, DiagContext);
-  yaml::document_iterator DI = Stream.begin();
-  yaml::Node *Root = DI->getRoot();
-  if (DI == Stream.end() || !Root) {
-    SM.PrintMessage(SMLoc(), SourceMgr::DK_Error, "expected root node");
-    return nullptr;
-  }
-
-  RedirectingFileSystemParser P(Stream);
-
-  std::unique_ptr<RedirectingFileSystem> FS(
-      new RedirectingFileSystem(std::move(ExternalFS)));
-
-  if (!YAMLFilePath.empty()) {
-    // Use the YAML path from -ivfsoverlay to compute the dir to be prefixed
-    // to each 'external-contents' path.
-    //
-    // Example:
-    //    -ivfsoverlay dummy.cache/vfs/vfs.yaml
-    // yields:
-    //  FS->ExternalContentsPrefixDir => /<absolute_path_to>/dummy.cache/vfs
-    //
-    SmallString<256> OverlayAbsDir = sys::path::parent_path(YAMLFilePath);
-    std::error_code EC = llvm::sys::fs::make_absolute(OverlayAbsDir);
-    assert(!EC && "Overlay dir final path must be absolute");
-    (void)EC;
-    FS->setExternalContentsPrefixDir(OverlayAbsDir);
-  }
-
-  if (!P.parse(Root, FS.get()))
-    return nullptr;
-
-  return FS.release();
-}
-
-ErrorOr<Entry *> RedirectingFileSystem::lookupPath(const Twine &Path_) {
-  SmallString<256> Path;
-  Path_.toVector(Path);
-
-  // Handle relative paths
-  if (std::error_code EC = makeAbsolute(Path))
-    return EC;
-
-  // Canonicalize path by removing ".", "..", "./", etc components. This is
-  // a VFS request, do bot bother about symlinks in the path components
-  // but canonicalize in order to perform the correct entry search.
-  if (UseCanonicalizedPaths) {
-    Path = sys::path::remove_leading_dotslash(Path);
-    sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-  }
-
-  if (Path.empty())
-    return make_error_code(llvm::errc::invalid_argument);
-
-  sys::path::const_iterator Start = sys::path::begin(Path);
-  sys::path::const_iterator End = sys::path::end(Path);
-  for (const auto &Root : Roots) {
-    ErrorOr<Entry *> Result = lookupPath(Start, End, Root.get());
-    if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
-      return Result;
-  }
-  return make_error_code(llvm::errc::no_such_file_or_directory);
-}
-
-ErrorOr<Entry *>
-RedirectingFileSystem::lookupPath(sys::path::const_iterator Start,
-                                  sys::path::const_iterator End, Entry *From) {
-#ifndef _WIN32
-  assert(!isTraversalComponent(*Start) &&
-         !isTraversalComponent(From->getName()) &&
-         "Paths should not contain traversal components");
-#else
-  // FIXME: this is here to support windows, remove it once canonicalized
-  // paths become globally default.
-  if (Start->equals("."))
-    ++Start;
-#endif
-
-  StringRef FromName = From->getName();
-
-  // Forward the search to the next component in case this is an empty one.
-  if (!FromName.empty()) {
-    if (CaseSensitive ? !Start->equals(FromName)
-                      : !Start->equals_lower(FromName))
-      // failure to match
-      return make_error_code(llvm::errc::no_such_file_or_directory);
-
-    ++Start;
-
-    if (Start == End) {
-      // Match!
-      return From;
-    }
-  }
-
-  auto *DE = dyn_cast<RedirectingDirectoryEntry>(From);
-  if (!DE)
-    return make_error_code(llvm::errc::not_a_directory);
-
-  for (const std::unique_ptr<Entry> &DirEntry :
-       llvm::make_range(DE->contents_begin(), DE->contents_end())) {
-    ErrorOr<Entry *> Result = lookupPath(Start, End, DirEntry.get());
-    if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
-      return Result;
-  }
-  return make_error_code(llvm::errc::no_such_file_or_directory);
-}
-
-static Status getRedirectedFileStatus(const Twine &Path, bool UseExternalNames,
-                                      Status ExternalStatus) {
-  Status S = ExternalStatus;
-  if (!UseExternalNames)
-    S = Status::copyWithNewName(S, Path.str());
-  S.IsVFSMapped = true;
-  return S;
-}
-
-ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path, Entry *E) {
-  assert(E != nullptr);
-  if (auto *F = dyn_cast<RedirectingFileEntry>(E)) {
-    ErrorOr<Status> S = ExternalFS->status(F->getExternalContentsPath());
-    assert(!S || S->getName() == F->getExternalContentsPath());
-    if (S)
-      return getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
-                                     *S);
-    return S;
-  } else { // directory
-    auto *DE = cast<RedirectingDirectoryEntry>(E);
-    return Status::copyWithNewName(DE->getStatus(), Path.str());
-  }
-}
-
-ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path) {
-  ErrorOr<Entry *> Result = lookupPath(Path);
-  if (!Result)
-    return Result.getError();
-  return status(Path, *Result);
-}
-
-namespace {
-
-/// Provide a file wrapper with an overriden status.
-class FileWithFixedStatus : public File {
-  std::unique_ptr<File> InnerFile;
-  Status S;
-
-public:
-  FileWithFixedStatus(std::unique_ptr<File> InnerFile, Status S)
-      : InnerFile(std::move(InnerFile)), S(std::move(S)) {}
-
-  ErrorOr<Status> status() override { return S; }
-  ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
-
-  getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
-            bool IsVolatile) override {
-    return InnerFile->getBuffer(Name, FileSize, RequiresNullTerminator,
-                                IsVolatile);
-  }
-
-  std::error_code close() override { return InnerFile->close(); }
-};
-
-} // namespace
-
-ErrorOr<std::unique_ptr<File>>
-RedirectingFileSystem::openFileForRead(const Twine &Path) {
-  ErrorOr<Entry *> E = lookupPath(Path);
-  if (!E)
-    return E.getError();
-
-  auto *F = dyn_cast<RedirectingFileEntry>(*E);
-  if (!F) // FIXME: errc::not_a_file?
-    return make_error_code(llvm::errc::invalid_argument);
-
-  auto Result = ExternalFS->openFileForRead(F->getExternalContentsPath());
-  if (!Result)
-    return Result;
-
-  auto ExternalStatus = (*Result)->status();
-  if (!ExternalStatus)
-    return ExternalStatus.getError();
-
-  // FIXME: Update the status with the name and VFSMapped.
-  Status S = getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
-                                     *ExternalStatus);
-  return std::unique_ptr<File>(
-      llvm::make_unique<FileWithFixedStatus>(std::move(*Result), S));
-}
-
-IntrusiveRefCntPtr<FileSystem>
-vfs::getVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
-                    SourceMgr::DiagHandlerTy DiagHandler,
-                    StringRef YAMLFilePath,
-                    void *DiagContext,
-                    IntrusiveRefCntPtr<FileSystem> ExternalFS) {
-  return RedirectingFileSystem::create(std::move(Buffer), DiagHandler,
-                                       YAMLFilePath, DiagContext,
-                                       std::move(ExternalFS));
-}
-
-static void getVFSEntries(Entry *SrcE, SmallVectorImpl<StringRef> &Path,
-                          SmallVectorImpl<YAMLVFSEntry> &Entries) {
-  auto Kind = SrcE->getKind();
-  if (Kind == EK_Directory) {
-    auto *DE = dyn_cast<RedirectingDirectoryEntry>(SrcE);
-    assert(DE && "Must be a directory");
-    for (std::unique_ptr<Entry> &SubEntry :
-         llvm::make_range(DE->contents_begin(), DE->contents_end())) {
-      Path.push_back(SubEntry->getName());
-      getVFSEntries(SubEntry.get(), Path, Entries);
-      Path.pop_back();
-    }
-    return;
-  }
-
-  assert(Kind == EK_File && "Must be a EK_File");
-  auto *FE = dyn_cast<RedirectingFileEntry>(SrcE);
-  assert(FE && "Must be a file");
-  SmallString<128> VPath;
-  for (auto &Comp : Path)
-    llvm::sys::path::append(VPath, Comp);
-  Entries.push_back(YAMLVFSEntry(VPath.c_str(), FE->getExternalContentsPath()));
-}
-
-void vfs::collectVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
-                             SourceMgr::DiagHandlerTy DiagHandler,
-                             StringRef YAMLFilePath,
-                             SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
-                             void *DiagContext,
-                             IntrusiveRefCntPtr<FileSystem> ExternalFS) {
-  RedirectingFileSystem *VFS = RedirectingFileSystem::create(
-      std::move(Buffer), DiagHandler, YAMLFilePath, DiagContext,
-      std::move(ExternalFS));
-  ErrorOr<Entry *> RootE = VFS->lookupPath("/");
-  if (!RootE)
-    return;
-  SmallVector<StringRef, 8> Components;
-  Components.push_back("/");
-  getVFSEntries(*RootE, Components, CollectedEntries);
-}
-
-UniqueID vfs::getNextVirtualUniqueID() {
-  static std::atomic<unsigned> UID;
-  unsigned ID = ++UID;
-  // The following assumes that uint64_t max will never collide with a real
-  // dev_t value from the OS.
-  return UniqueID(std::numeric_limits<uint64_t>::max(), ID);
-}
-
-void YAMLVFSWriter::addFileMapping(StringRef VirtualPath, StringRef RealPath) {
-  assert(sys::path::is_absolute(VirtualPath) && "virtual path not absolute");
-  assert(sys::path::is_absolute(RealPath) && "real path not absolute");
-  assert(!pathHasTraversal(VirtualPath) && "path traversal is not supported");
-  Mappings.emplace_back(VirtualPath, RealPath);
-}
-
-namespace {
-
-class JSONWriter {
-  llvm::raw_ostream &OS;
-  SmallVector<StringRef, 16> DirStack;
-
-  unsigned getDirIndent() { return 4 * DirStack.size(); }
-  unsigned getFileIndent() { return 4 * (DirStack.size() + 1); }
-  bool containedIn(StringRef Parent, StringRef Path);
-  StringRef containedPart(StringRef Parent, StringRef Path);
-  void startDirectory(StringRef Path);
-  void endDirectory();
-  void writeEntry(StringRef VPath, StringRef RPath);
-
-public:
-  JSONWriter(llvm::raw_ostream &OS) : OS(OS) {}
-
-  void write(ArrayRef<YAMLVFSEntry> Entries, Optional<bool> UseExternalNames,
-             Optional<bool> IsCaseSensitive, Optional<bool> IsOverlayRelative,
-             Optional<bool> IgnoreNonExistentContents, StringRef OverlayDir);
-};
-
-} // namespace
-
-bool JSONWriter::containedIn(StringRef Parent, StringRef Path) {
-  using namespace llvm::sys;
-
-  // Compare each path component.
-  auto IParent = path::begin(Parent), EParent = path::end(Parent);
-  for (auto IChild = path::begin(Path), EChild = path::end(Path);
-       IParent != EParent && IChild != EChild; ++IParent, ++IChild) {
-    if (*IParent != *IChild)
-      return false;
-  }
-  // Have we exhausted the parent path?
-  return IParent == EParent;
-}
-
-StringRef JSONWriter::containedPart(StringRef Parent, StringRef Path) {
-  assert(!Parent.empty());
-  assert(containedIn(Parent, Path));
-  return Path.slice(Parent.size() + 1, StringRef::npos);
-}
-
-void JSONWriter::startDirectory(StringRef Path) {
-  StringRef Name =
-      DirStack.empty() ? Path : containedPart(DirStack.back(), Path);
-  DirStack.push_back(Path);
-  unsigned Indent = getDirIndent();
-  OS.indent(Indent) << "{\n";
-  OS.indent(Indent + 2) << "'type': 'directory',\n";
-  OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(Name) << "\",\n";
-  OS.indent(Indent + 2) << "'contents': [\n";
-}
-
-void JSONWriter::endDirectory() {
-  unsigned Indent = getDirIndent();
-  OS.indent(Indent + 2) << "]\n";
-  OS.indent(Indent) << "}";
-
-  DirStack.pop_back();
-}
-
-void JSONWriter::writeEntry(StringRef VPath, StringRef RPath) {
-  unsigned Indent = getFileIndent();
-  OS.indent(Indent) << "{\n";
-  OS.indent(Indent + 2) << "'type': 'file',\n";
-  OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(VPath) << "\",\n";
-  OS.indent(Indent + 2) << "'external-contents': \""
-                        << llvm::yaml::escape(RPath) << "\"\n";
-  OS.indent(Indent) << "}";
-}
-
-void JSONWriter::write(ArrayRef<YAMLVFSEntry> Entries,
-                       Optional<bool> UseExternalNames,
-                       Optional<bool> IsCaseSensitive,
-                       Optional<bool> IsOverlayRelative,
-                       Optional<bool> IgnoreNonExistentContents,
-                       StringRef OverlayDir) {
-  using namespace llvm::sys;
-
-  OS << "{\n"
-        "  'version': 0,\n";
-  if (IsCaseSensitive.hasValue())
-    OS << "  'case-sensitive': '"
-       << (IsCaseSensitive.getValue() ? "true" : "false") << "',\n";
-  if (UseExternalNames.hasValue())
-    OS << "  'use-external-names': '"
-       << (UseExternalNames.getValue() ? "true" : "false") << "',\n";
-  bool UseOverlayRelative = false;
-  if (IsOverlayRelative.hasValue()) {
-    UseOverlayRelative = IsOverlayRelative.getValue();
-    OS << "  'overlay-relative': '"
-       << (UseOverlayRelative ? "true" : "false") << "',\n";
-  }
-  if (IgnoreNonExistentContents.hasValue())
-    OS << "  'ignore-non-existent-contents': '"
-       << (IgnoreNonExistentContents.getValue() ? "true" : "false") << "',\n";
-  OS << "  'roots': [\n";
-
-  if (!Entries.empty()) {
-    const YAMLVFSEntry &Entry = Entries.front();
-    startDirectory(path::parent_path(Entry.VPath));
-
-    StringRef RPath = Entry.RPath;
-    if (UseOverlayRelative) {
-      unsigned OverlayDirLen = OverlayDir.size();
-      assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&
-             "Overlay dir must be contained in RPath");
-      RPath = RPath.slice(OverlayDirLen, RPath.size());
-    }
-
-    writeEntry(path::filename(Entry.VPath), RPath);
-
-    for (const auto &Entry : Entries.slice(1)) {
-      StringRef Dir = path::parent_path(Entry.VPath);
-      if (Dir == DirStack.back())
-        OS << ",\n";
-      else {
-        while (!DirStack.empty() && !containedIn(DirStack.back(), Dir)) {
-          OS << "\n";
-          endDirectory();
-        }
-        OS << ",\n";
-        startDirectory(Dir);
-      }
-      StringRef RPath = Entry.RPath;
-      if (UseOverlayRelative) {
-        unsigned OverlayDirLen = OverlayDir.size();
-        assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&
-               "Overlay dir must be contained in RPath");
-        RPath = RPath.slice(OverlayDirLen, RPath.size());
-      }
-      writeEntry(path::filename(Entry.VPath), RPath);
-    }
-
-    while (!DirStack.empty()) {
-      OS << "\n";
-      endDirectory();
-    }
-    OS << "\n";
-  }
-
-  OS << "  ]\n"
-     << "}\n";
-}
-
-void YAMLVFSWriter::write(llvm::raw_ostream &OS) {
-  llvm::sort(Mappings, [](const YAMLVFSEntry &LHS, const YAMLVFSEntry &RHS) {
-    return LHS.VPath < RHS.VPath;
-  });
-
-  JSONWriter(OS).write(Mappings, UseExternalNames, IsCaseSensitive,
-                       IsOverlayRelative, IgnoreNonExistentContents,
-                       OverlayDir);
-}
-
-VFSFromYamlDirIterImpl::VFSFromYamlDirIterImpl(
-    const Twine &_Path, RedirectingDirectoryEntry::iterator Begin,
-    RedirectingDirectoryEntry::iterator End, std::error_code &EC)
-    : Dir(_Path.str()), Current(Begin), End(End) {
-  EC = incrementImpl();
-}
-
-std::error_code VFSFromYamlDirIterImpl::increment() {
-  assert(Current != End && "cannot iterate past end");
-  ++Current;
-  return incrementImpl();
-}
-
-std::error_code VFSFromYamlDirIterImpl::incrementImpl() {
-  while (Current != End) {
-    SmallString<128> PathStr(Dir);
-    llvm::sys::path::append(PathStr, (*Current)->getName());
-    sys::fs::file_type Type;
-    switch ((*Current)->getKind()) {
-      case EK_Directory:
-        Type = sys::fs::file_type::directory_file;
-        break;
-      case EK_File:
-        Type = sys::fs::file_type::regular_file;
-        break;
-    }
-    CurrentEntry = directory_entry(PathStr.str(), Type);
-    break;
-  }
-
-  if (Current == End)
-    CurrentEntry = directory_entry();
-  return {};
-}
-
-vfs::recursive_directory_iterator::recursive_directory_iterator(FileSystem &FS_,
-                                                           const Twine &Path,
-                                                           std::error_code &EC)
-    : FS(&FS_) {
-  directory_iterator I = FS->dir_begin(Path, EC);
-  if (I != directory_iterator()) {
-    State = std::make_shared<IterState>();
-    State->push(I);
-  }
-}
-
-vfs::recursive_directory_iterator &
-recursive_directory_iterator::increment(std::error_code &EC) {
-  assert(FS && State && !State->empty() && "incrementing past end");
-  assert(!State->top()->path().empty() && "non-canonical end iterator");
-  vfs::directory_iterator End;
-  if (State->top()->type() == sys::fs::file_type::directory_file) {
-    vfs::directory_iterator I = FS->dir_begin(State->top()->path(), EC);
-    if (I != End) {
-      State->push(I);
-      return *this;
-    }
-  }
-
-  while (!State->empty() && State->top().increment(EC) == End)
-    State->pop();
-
-  if (State->empty())
-    State.reset(); // end iterator
-
-  return *this;
-}

lib/Driver/Distro.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Driver/Distro.h"
+#include "clang/Basic/LLVM.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -17,7 +18,7 @@
 using namespace clang::driver;
 using namespace clang;
 
-static Distro::DistroType DetectDistro(vfs::FileSystem &VFS) {
+static Distro::DistroType DetectDistro(llvm::vfs::FileSystem &VFS) {
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
       VFS.getBufferForFile("/etc/lsb-release");
   if (File) {
@@ -139,4 +140,4 @@ static Distro::DistroType DetectDistro(vfs::FileSystem &VFS) {
   return Distro::UnknownDistro;
 }
 
-Distro::Distro(vfs::FileSystem &VFS) : DistroVal(DetectDistro(VFS)) {}
+Distro::Distro(llvm::vfs::FileSystem &VFS) : DistroVal(DetectDistro(VFS)) {}

lib/Driver/Driver.cpp

@@ -43,7 +43,6 @@
 #include "ToolChains/WebAssembly.h"
 #include "ToolChains/XCore.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Compilation.h"
@@ -75,6 +74,7 @@
 #include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
 #include <memory>
@@ -89,7 +89,7 @@ using namespace llvm::opt;
 
 Driver::Driver(StringRef ClangExecutable, StringRef TargetTriple,
                DiagnosticsEngine &Diags,
-               IntrusiveRefCntPtr<vfs::FileSystem> VFS)
+               IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS)
     : Opts(createDriverOptTable()), Diags(Diags), VFS(std::move(VFS)),
       Mode(GCCMode), SaveTemps(SaveTempsNone), BitcodeEmbed(EmbedNone),
       LTOMode(LTOK_None), ClangExecutable(ClangExecutable),
@@ -104,7 +104,7 @@ Driver::Driver(StringRef ClangExecutable, StringRef TargetTriple,
 
   // Provide a sane fallback if no VFS is specified.
   if (!this->VFS)
-    this->VFS = vfs::getRealFileSystem();
+    this->VFS = llvm::vfs::getRealFileSystem();
 
   Name = llvm::sys::path::filename(ClangExecutable);
   Dir = llvm::sys::path::parent_path(ClangExecutable);

lib/Driver/ToolChain.cpp

@@ -13,7 +13,6 @@
 #include "ToolChains/Clang.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Driver.h"
@@ -39,6 +38,7 @@
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <cassert>
 #include <cstddef>
 #include <cstring>
@@ -99,7 +99,9 @@ void ToolChain::setTripleEnvironment(llvm::Triple::EnvironmentType Env) {
 
 ToolChain::~ToolChain() = default;
 
-vfs::FileSystem &ToolChain::getVFS() const { return getDriver().getVFS(); }
+llvm::vfs::FileSystem &ToolChain::getVFS() const {
+  return getDriver().getVFS();
+}
 
 bool ToolChain::useIntegratedAs() const {
   return Args.hasFlag(options::OPT_fintegrated_as,

lib/Driver/ToolChains/BareMetal.cpp

@@ -13,13 +13,13 @@
 #include "InputInfo.h"
 #include "Gnu.h"
 
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm::opt;
@@ -119,8 +119,9 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(
     std::error_code EC;
     Generic_GCC::GCCVersion Version = {"", -1, -1, -1, "", "", ""};
     // Walk the subdirs, and find the one with the newest gcc version:
-    for (vfs::directory_iterator LI =
-           getDriver().getVFS().dir_begin(Dir.str(), EC), LE;
+    for (llvm::vfs::directory_iterator
+             LI = getDriver().getVFS().dir_begin(Dir.str(), EC),
+             LE;
          !EC && LI != LE; LI = LI.increment(EC)) {
       StringRef VersionText = llvm::sys::path::filename(LI->path());
       auto CandidateVersion = Generic_GCC::GCCVersion::Parse(VersionText);

lib/Driver/ToolChains/CommonArgs.cpp

@@ -14,14 +14,13 @@
 #include "Arch/PPC.h"
 #include "Arch/SystemZ.h"
 #include "Arch/X86.h"
-#include "Hexagon.h"
 #include "HIP.h"
+#include "Hexagon.h"
 #include "InputInfo.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Compilation.h"
@@ -52,6 +51,7 @@
 #include "llvm/Support/Program.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/TargetParser.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLParser.h"
 
 using namespace clang::driver;

lib/Driver/ToolChains/Cuda.cpp

@@ -11,7 +11,6 @@
 #include "CommonArgs.h"
 #include "InputInfo.h"
 #include "clang/Basic/Cuda.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Distro.h"
@@ -23,6 +22,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <system_error>
 
 using namespace clang::driver;

lib/Driver/ToolChains/Darwin.cpp

@@ -12,7 +12,6 @@
 #include "CommonArgs.h"
 #include "clang/Basic/AlignedAllocation.h"
 #include "clang/Basic/ObjCRuntime.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
@@ -23,6 +22,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/TargetParser.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <cstdlib> // ::getenv
 
 using namespace clang::driver;

lib/Driver/ToolChains/FreeBSD.cpp

@@ -12,11 +12,11 @@
 #include "Arch/Mips.h"
 #include "Arch/Sparc.h"
 #include "CommonArgs.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/SanitizerArgs.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/VirtualFileSystem.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;

lib/Driver/ToolChains/Gnu.cpp

@@ -16,7 +16,6 @@
 #include "Arch/SystemZ.h"
 #include "CommonArgs.h"
 #include "Linux.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
@@ -27,6 +26,7 @@
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TargetParser.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <system_error>
 
 using namespace clang::driver;
@@ -791,10 +791,10 @@ namespace {
 // Filter to remove Multilibs that don't exist as a suffix to Path
 class FilterNonExistent {
   StringRef Base, File;
-  vfs::FileSystem &VFS;
+  llvm::vfs::FileSystem &VFS;
 
 public:
-  FilterNonExistent(StringRef Base, StringRef File, vfs::FileSystem &VFS)
+  FilterNonExistent(StringRef Base, StringRef File, llvm::vfs::FileSystem &VFS)
       : Base(Base), File(File), VFS(VFS) {}
   bool operator()(const Multilib &M) {
     return !VFS.exists(Base + M.gccSuffix() + File);
@@ -940,7 +940,7 @@ static bool findMipsCsMultilibs(const Multilib::flags_list &Flags,
   return false;
 }
 
-static bool findMipsAndroidMultilibs(vfs::FileSystem &VFS, StringRef Path,
+static bool findMipsAndroidMultilibs(llvm::vfs::FileSystem &VFS, StringRef Path,
                                      const Multilib::flags_list &Flags,
                                      FilterNonExistent &NonExistent,
                                      DetectedMultilibs &Result) {
@@ -1762,7 +1762,8 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
 
     std::string PrefixDir = SysRoot.str() + "/usr/gcc";
     std::error_code EC;
-    for (vfs::directory_iterator LI = D.getVFS().dir_begin(PrefixDir, EC), LE;
+    for (llvm::vfs::directory_iterator LI = D.getVFS().dir_begin(PrefixDir, EC),
+                                       LE;
          !EC && LI != LE; LI = LI.increment(EC)) {
       StringRef VersionText = llvm::sys::path::filename(LI->path());
       GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
@@ -2205,7 +2206,7 @@ void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
 
     StringRef LibSuffix = Suffix.LibSuffix;
     std::error_code EC;
-    for (vfs::directory_iterator
+    for (llvm::vfs::directory_iterator
              LI = D.getVFS().dir_begin(LibDir + "/" + LibSuffix, EC),
              LE;
          !EC && LI != LE; LI = LI.increment(EC)) {

lib/Driver/ToolChains/Hexagon.cpp

@@ -8,9 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "Hexagon.h"
-#include "InputInfo.h"
 #include "CommonArgs.h"
-#include "clang/Basic/VirtualFileSystem.h"
+#include "InputInfo.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
@@ -19,6 +18,7 @@
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;

lib/Driver/ToolChains/Linux.cpp

@@ -13,7 +13,6 @@
 #include "Arch/PPC.h"
 #include "Arch/RISCV.h"
 #include "CommonArgs.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Distro.h"
 #include "clang/Driver/Driver.h"
@@ -23,6 +22,7 @@
 #include "llvm/ProfileData/InstrProf.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <system_error>
 
 using namespace clang::driver;

lib/Driver/ToolChains/Minix.cpp

@@ -8,13 +8,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "Minix.h"
-#include "InputInfo.h"
 #include "CommonArgs.h"
-#include "clang/Basic/VirtualFileSystem.h"
+#include "InputInfo.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/Options.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/VirtualFileSystem.h"
 
 using namespace clang::driver;
 using namespace clang;

lib/Format/Format.cpp

@@ -29,7 +29,6 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Tooling/Inclusions/HeaderIncludes.h"
 #include "llvm/ADT/STLExtras.h"
@@ -38,6 +37,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Regex.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLTraits.h"
 #include <algorithm>
 #include <memory>
@@ -2326,9 +2326,10 @@ const char *DefaultFallbackStyle = "LLVM";
 
 llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
                                      StringRef FallbackStyleName,
-                                     StringRef Code, vfs::FileSystem *FS) {
+                                     StringRef Code,
+                                     llvm::vfs::FileSystem *FS) {
   if (!FS) {
-    FS = vfs::getRealFileSystem().get();
+    FS = llvm::vfs::getRealFileSystem().get();
   }
   FormatStyle Style = getLLVMStyle();
   Style.Language = guessLanguage(FileName, Code);

lib/Frontend/ASTUnit.cpp

@@ -37,7 +37,6 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendAction.h"
@@ -88,6 +87,7 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/Timer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <atomic>
@@ -155,9 +155,8 @@ static bool moveOnNoError(llvm::ErrorOr<T> Val, T &Output) {
 /// and file-to-buffer remappings inside \p Invocation.
 static std::unique_ptr<llvm::MemoryBuffer>
 getBufferForFileHandlingRemapping(const CompilerInvocation &Invocation,
-                                  vfs::FileSystem *VFS,
-                                  StringRef FilePath,
-                                  bool isVolatile) {
+                                  llvm::vfs::FileSystem *VFS,
+                                  StringRef FilePath, bool isVolatile) {
   const auto &PreprocessorOpts = Invocation.getPreprocessorOpts();
 
   // Try to determine if the main file has been remapped, either from the
@@ -752,7 +751,8 @@ std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->Diagnostics = Diags;
-  IntrusiveRefCntPtr<vfs::FileSystem> VFS = vfs::getRealFileSystem();
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
+      llvm::vfs::getRealFileSystem();
   AST->FileMgr = new FileManager(FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->SourceMgr = new SourceManager(AST->getDiagnostics(),
@@ -1074,7 +1074,7 @@ static void checkAndSanitizeDiags(SmallVectorImpl<StoredDiagnostic> &
 /// contain any translation-unit information, false otherwise.
 bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                     std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer,
-                    IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+                    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   if (!Invocation)
     return true;
 
@@ -1082,7 +1082,7 @@ bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
   if (OverrideMainBuffer) {
     assert(Preamble &&
            "No preamble was built, but OverrideMainBuffer is not null");
-    IntrusiveRefCntPtr<vfs::FileSystem> OldVFS = VFS;
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> OldVFS = VFS;
     Preamble->AddImplicitPreamble(*CCInvocation, VFS, OverrideMainBuffer.get());
     if (OldVFS != VFS && FileMgr) {
       assert(OldVFS == FileMgr->getVirtualFileSystem() &&
@@ -1279,7 +1279,7 @@ std::unique_ptr<llvm::MemoryBuffer>
 ASTUnit::getMainBufferWithPrecompiledPreamble(
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     CompilerInvocation &PreambleInvocationIn,
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS, bool AllowRebuild,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool AllowRebuild,
     unsigned MaxLines) {
   auto MainFilePath =
       PreambleInvocationIn.getFrontendOpts().Inputs[0].getFile();
@@ -1468,7 +1468,7 @@ ASTUnit::create(std::shared_ptr<CompilerInvocation> CI,
                 bool CaptureDiagnostics, bool UserFilesAreVolatile) {
   std::unique_ptr<ASTUnit> AST(new ASTUnit(false));
   ConfigureDiags(Diags, *AST, CaptureDiagnostics);
-  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
       createVFSFromCompilerInvocation(*CI, *Diags);
   AST->Diagnostics = Diags;
   AST->FileSystemOpts = CI->getFileSystemOpts();
@@ -1630,7 +1630,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(
 bool ASTUnit::LoadFromCompilerInvocation(
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     unsigned PrecompilePreambleAfterNParses,
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   if (!Invocation)
     return true;
 
@@ -1709,7 +1709,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     bool AllowPCHWithCompilerErrors, SkipFunctionBodiesScope SkipFunctionBodies,
     bool SingleFileParse, bool UserFilesAreVolatile, bool ForSerialization,
     llvm::Optional<StringRef> ModuleFormat, std::unique_ptr<ASTUnit> *ErrAST,
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   assert(Diags.get() && "no DiagnosticsEngine was provided");
 
   SmallVector<StoredDiagnostic, 4> StoredDiagnostics;
@@ -1754,7 +1754,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   AST->Diagnostics = Diags;
   AST->FileSystemOpts = CI->getFileSystemOpts();
   if (!VFS)
-    VFS = vfs::getRealFileSystem();
+    VFS = llvm::vfs::getRealFileSystem();
   VFS = createVFSFromCompilerInvocation(*CI, *Diags, VFS);
   AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->PCMCache = new MemoryBufferCache;
@@ -1794,7 +1794,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
 
 bool ASTUnit::Reparse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                       ArrayRef<RemappedFile> RemappedFiles,
-                      IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   if (!Invocation)
     return true;
 

lib/Frontend/CacheTokens.cpp

@@ -556,8 +556,8 @@ public:
   ~StatListener() override {}
 
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                       std::unique_ptr<vfs::File> *F,
-                       vfs::FileSystem &FS) override {
+                       std::unique_ptr<llvm::vfs::File> *F,
+                       llvm::vfs::FileSystem &FS) override {
     LookupResult Result = statChained(Path, Data, isFile, F, FS);
 
     if (Result == CacheMissing) // Failed 'stat'.

lib/Frontend/CompilerInstance.cpp

@@ -177,9 +177,9 @@ static void collectIncludePCH(CompilerInstance &CI,
   std::error_code EC;
   SmallString<128> DirNative;
   llvm::sys::path::native(PCHDir->getName(), DirNative);
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
   SimpleASTReaderListener Validator(CI.getPreprocessor());
-  for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+  for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
        Dir != DirEnd && !EC; Dir.increment(EC)) {
     // Check whether this is an AST file. ASTReader::isAcceptableASTFile is not
     // used here since we're not interested in validating the PCH at this time,
@@ -198,14 +198,14 @@ static void collectVFSEntries(CompilerInstance &CI,
     return;
 
   // Collect all VFS found.
-  SmallVector<vfs::YAMLVFSEntry, 16> VFSEntries;
+  SmallVector<llvm::vfs::YAMLVFSEntry, 16> VFSEntries;
   for (const std::string &VFSFile : CI.getHeaderSearchOpts().VFSOverlayFiles) {
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buffer =
         llvm::MemoryBuffer::getFile(VFSFile);
     if (!Buffer)
       return;
-    vfs::collectVFSFromYAML(std::move(Buffer.get()), /*DiagHandler*/ nullptr,
-                            VFSFile, VFSEntries);
+    llvm::vfs::collectVFSFromYAML(std::move(Buffer.get()),
+                                  /*DiagHandler*/ nullptr, VFSFile, VFSEntries);
   }
 
   for (auto &E : VFSEntries)
@@ -303,7 +303,7 @@ CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
 
 FileManager *CompilerInstance::createFileManager() {
   if (!hasVirtualFileSystem()) {
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =
         createVFSFromCompilerInvocation(getInvocation(), getDiagnostics());
     setVirtualFileSystem(VFS);
   }

lib/Frontend/CompilerInvocation.cpp

@@ -23,7 +23,6 @@
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Basic/Visibility.h"
 #include "clang/Basic/XRayInstr.h"
 #include "clang/Config/config.h"
@@ -77,6 +76,7 @@
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetOptions.h"
 #include <algorithm>
@@ -3245,21 +3245,21 @@ void BuryPointer(const void *Ptr) {
   GraveYard[Idx] = Ptr;
 }
 
-IntrusiveRefCntPtr<vfs::FileSystem>
+IntrusiveRefCntPtr<llvm::vfs::FileSystem>
 createVFSFromCompilerInvocation(const CompilerInvocation &CI,
                                 DiagnosticsEngine &Diags) {
-  return createVFSFromCompilerInvocation(CI, Diags, vfs::getRealFileSystem());
+  return createVFSFromCompilerInvocation(CI, Diags,
+                                         llvm::vfs::getRealFileSystem());
 }
 
-IntrusiveRefCntPtr<vfs::FileSystem>
-createVFSFromCompilerInvocation(const CompilerInvocation &CI,
-                                DiagnosticsEngine &Diags,
-                                IntrusiveRefCntPtr<vfs::FileSystem> BaseFS) {
+IntrusiveRefCntPtr<llvm::vfs::FileSystem> createVFSFromCompilerInvocation(
+    const CompilerInvocation &CI, DiagnosticsEngine &Diags,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS) {
   if (CI.getHeaderSearchOpts().VFSOverlayFiles.empty())
     return BaseFS;
 
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> Overlay(
-      new vfs::OverlayFileSystem(BaseFS));
+  IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> Overlay(
+      new llvm::vfs::OverlayFileSystem(BaseFS));
   // earlier vfs files are on the bottom
   for (const auto &File : CI.getHeaderSearchOpts().VFSOverlayFiles) {
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buffer =
@@ -3269,7 +3269,7 @@ createVFSFromCompilerInvocation(const CompilerInvocation &CI,
       continue;
     }
 
-    IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getVFSFromYAML(
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = llvm::vfs::getVFSFromYAML(
         std::move(Buffer.get()), /*DiagHandler*/ nullptr, File);
     if (FS)
       Overlay->pushOverlay(FS);

lib/Frontend/CreateInvocationFromCommandLine.cpp

@@ -32,7 +32,7 @@ using namespace llvm::opt;
 /// argument vector.
 std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
     ArrayRef<const char *> ArgList, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.

lib/Frontend/FrontendAction.cpp

@@ -342,8 +342,8 @@ static std::error_code collectModuleHeaderIncludes(
     SmallString<128> DirNative;
     llvm::sys::path::native(UmbrellaDir.Entry->getName(), DirNative);
 
-    vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-    for (vfs::recursive_directory_iterator Dir(FS, DirNative, EC), End;
+    llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+    for (llvm::vfs::recursive_directory_iterator Dir(FS, DirNative, EC), End;
          Dir != End && !EC; Dir.increment(EC)) {
       // Check whether this entry has an extension typically associated with
       // headers.
@@ -696,8 +696,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
       SmallString<128> DirNative;
       llvm::sys::path::native(PCHDir->getName(), DirNative);
       bool Found = false;
-      vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-      for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+      llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+      for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC),
+                                         DirEnd;
            Dir != DirEnd && !EC; Dir.increment(EC)) {
         // Check whether this is an acceptable AST file.
         if (ASTReader::isAcceptableASTFile(

lib/Frontend/PrecompiledPreamble.cpp

@@ -14,7 +14,6 @@
 #include "clang/Frontend/PrecompiledPreamble.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendActions.h"
@@ -30,6 +29,7 @@
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/MutexGuard.h"
 #include "llvm/Support/Process.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <limits>
 #include <utility>
 
@@ -48,17 +48,17 @@ StringRef getInMemoryPreamblePath() {
 #endif
 }
 
-IntrusiveRefCntPtr<vfs::FileSystem>
+IntrusiveRefCntPtr<llvm::vfs::FileSystem>
 createVFSOverlayForPreamblePCH(StringRef PCHFilename,
                                std::unique_ptr<llvm::MemoryBuffer> PCHBuffer,
-                               IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+                               IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   // We want only the PCH file from the real filesystem to be available,
   // so we create an in-memory VFS with just that and overlay it on top.
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> PCHFS(
-      new vfs::InMemoryFileSystem());
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> PCHFS(
+      new llvm::vfs::InMemoryFileSystem());
   PCHFS->addFile(PCHFilename, 0, std::move(PCHBuffer));
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> Overlay(
-      new vfs::OverlayFileSystem(VFS));
+  IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> Overlay(
+      new llvm::vfs::OverlayFileSystem(VFS));
   Overlay->pushOverlay(PCHFS);
   return Overlay;
 }
@@ -232,7 +232,8 @@ PreambleBounds clang::ComputePreambleBounds(const LangOptions &LangOpts,
 llvm::ErrorOr<PrecompiledPreamble> PrecompiledPreamble::Build(
     const CompilerInvocation &Invocation,
     const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
-    DiagnosticsEngine &Diagnostics, IntrusiveRefCntPtr<vfs::FileSystem> VFS,
+    DiagnosticsEngine &Diagnostics,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps, bool StoreInMemory,
     PreambleCallbacks &Callbacks) {
   assert(VFS && "VFS is null");
@@ -410,7 +411,7 @@ std::size_t PrecompiledPreamble::getSize() const {
 bool PrecompiledPreamble::CanReuse(const CompilerInvocation &Invocation,
                                    const llvm::MemoryBuffer *MainFileBuffer,
                                    PreambleBounds Bounds,
-                                   vfs::FileSystem *VFS) const {
+                                   llvm::vfs::FileSystem *VFS) const {
 
   assert(
       Bounds.Size <= MainFileBuffer->getBufferSize() &&
@@ -437,7 +438,7 @@ bool PrecompiledPreamble::CanReuse(const CompilerInvocation &Invocation,
   // remapping or unsaved_files.
   std::map<llvm::sys::fs::UniqueID, PreambleFileHash> OverriddenFiles;
   for (const auto &R : PreprocessorOpts.RemappedFiles) {
-    vfs::Status Status;
+    llvm::vfs::Status Status;
     if (!moveOnNoError(VFS->status(R.second), Status)) {
       // If we can't stat the file we're remapping to, assume that something
       // horrible happened.
@@ -449,7 +450,7 @@ bool PrecompiledPreamble::CanReuse(const CompilerInvocation &Invocation,
   }
 
   for (const auto &RB : PreprocessorOpts.RemappedFileBuffers) {
-    vfs::Status Status;
+    llvm::vfs::Status Status;
     if (!moveOnNoError(VFS->status(RB.first), Status))
       return false;
 
@@ -459,7 +460,7 @@ bool PrecompiledPreamble::CanReuse(const CompilerInvocation &Invocation,
 
   // Check whether anything has changed.
   for (const auto &F : FilesInPreamble) {
-    vfs::Status Status;
+    llvm::vfs::Status Status;
     if (!moveOnNoError(VFS->status(F.first()), Status)) {
       // If we can't stat the file, assume that something horrible happened.
       return false;
@@ -485,14 +486,14 @@ bool PrecompiledPreamble::CanReuse(const CompilerInvocation &Invocation,
 }
 
 void PrecompiledPreamble::AddImplicitPreamble(
-    CompilerInvocation &CI, IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+    CompilerInvocation &CI, IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
     llvm::MemoryBuffer *MainFileBuffer) const {
   PreambleBounds Bounds(PreambleBytes.size(), PreambleEndsAtStartOfLine);
   configurePreamble(Bounds, CI, VFS, MainFileBuffer);
 }
 
 void PrecompiledPreamble::OverridePreamble(
-    CompilerInvocation &CI, IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+    CompilerInvocation &CI, IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
     llvm::MemoryBuffer *MainFileBuffer) const {
   auto Bounds = ComputePreambleBounds(*CI.getLangOpts(), MainFileBuffer, 0);
   configurePreamble(Bounds, CI, VFS, MainFileBuffer);
@@ -680,7 +681,7 @@ PrecompiledPreamble::PreambleFileHash::createForMemoryBuffer(
 
 void PrecompiledPreamble::configurePreamble(
     PreambleBounds Bounds, CompilerInvocation &CI,
-    IntrusiveRefCntPtr<vfs::FileSystem> &VFS,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
     llvm::MemoryBuffer *MainFileBuffer) const {
   assert(VFS);
 
@@ -701,13 +702,14 @@ void PrecompiledPreamble::configurePreamble(
 
 void PrecompiledPreamble::setupPreambleStorage(
     const PCHStorage &Storage, PreprocessorOptions &PreprocessorOpts,
-    IntrusiveRefCntPtr<vfs::FileSystem> &VFS) {
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS) {
   if (Storage.getKind() == PCHStorage::Kind::TempFile) {
     const TempPCHFile &PCHFile = Storage.asFile();
     PreprocessorOpts.ImplicitPCHInclude = PCHFile.getFilePath();
 
     // Make sure we can access the PCH file even if we're using a VFS
-    IntrusiveRefCntPtr<vfs::FileSystem> RealFS = vfs::getRealFileSystem();
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> RealFS =
+        llvm::vfs::getRealFileSystem();
     auto PCHPath = PCHFile.getFilePath();
     if (VFS == RealFS || VFS->exists(PCHPath))
       return;

lib/Index/SimpleFormatContext.h

@@ -36,12 +36,10 @@ class SimpleFormatContext {
 public:
   SimpleFormatContext(LangOptions Options)
       : DiagOpts(new DiagnosticOptions()),
-        Diagnostics(new DiagnosticsEngine(new DiagnosticIDs,
-                                          DiagOpts.get())),
-        InMemoryFileSystem(new vfs::InMemoryFileSystem),
+        Diagnostics(new DiagnosticsEngine(new DiagnosticIDs, DiagOpts.get())),
+        InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
         Files(FileSystemOptions(), InMemoryFileSystem),
-        Sources(*Diagnostics, Files),
-        Rewrite(Sources, Options) {
+        Sources(*Diagnostics, Files), Rewrite(Sources, Options) {
     Diagnostics->setClient(new IgnoringDiagConsumer, true);
   }
 
@@ -63,7 +61,7 @@ public:
 
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
   IntrusiveRefCntPtr<DiagnosticsEngine> Diagnostics;
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem;
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem;
   FileManager Files;
   SourceManager Sources;
   Rewriter Rewrite;

lib/Lex/HeaderSearch.cpp

@@ -17,7 +17,6 @@
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/DirectoryLookup.h"
 #include "clang/Lex/ExternalPreprocessorSource.h"
 #include "clang/Lex/HeaderMap.h"
@@ -35,6 +34,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
@@ -1571,8 +1571,9 @@ void HeaderSearch::collectAllModules(SmallVectorImpl<Module *> &Modules) {
                                 DirNative);
 
         // Search each of the ".framework" directories to load them as modules.
-        vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-        for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+        llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+        for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC),
+                                           DirEnd;
              Dir != DirEnd && !EC; Dir.increment(EC)) {
           if (llvm::sys::path::extension(Dir->path()) != ".framework")
             continue;
@@ -1639,8 +1640,8 @@ void HeaderSearch::loadSubdirectoryModuleMaps(DirectoryLookup &SearchDir) {
   std::error_code EC;
   SmallString<128> DirNative;
   llvm::sys::path::native(SearchDir.getDir()->getName(), DirNative);
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-  for (vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
        Dir != DirEnd && !EC; Dir.increment(EC)) {
     bool IsFramework = llvm::sys::path::extension(Dir->path()) == ".framework";
     if (IsFramework == SearchDir.isFramework())

lib/Lex/ModuleMap.cpp

@@ -22,7 +22,6 @@
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Lex/LexDiagnostic.h"
@@ -43,6 +42,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
@@ -1020,9 +1020,10 @@ Module *ModuleMap::inferFrameworkModule(const DirectoryEntry *FrameworkDir,
     = StringRef(FrameworkDir->getName());
   llvm::sys::path::append(SubframeworksDirName, "Frameworks");
   llvm::sys::path::native(SubframeworksDirName);
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
-  for (vfs::directory_iterator Dir = FS.dir_begin(SubframeworksDirName, EC),
-                               DirEnd;
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  for (llvm::vfs::directory_iterator
+           Dir = FS.dir_begin(SubframeworksDirName, EC),
+           DirEnd;
        Dir != DirEnd && !EC; Dir.increment(EC)) {
     if (!StringRef(Dir->path()).endswith(".framework"))
       continue;
@@ -2394,8 +2395,9 @@ void ModuleMapParser::parseUmbrellaDirDecl(SourceLocation UmbrellaLoc) {
     // uncommonly used Tcl module on Darwin platforms.
     std::error_code EC;
     SmallVector<Module::Header, 6> Headers;
-    vfs::FileSystem &FS = *SourceMgr.getFileManager().getVirtualFileSystem();
-    for (vfs::recursive_directory_iterator I(FS, Dir->getName(), EC), E;
+    llvm::vfs::FileSystem &FS =
+        *SourceMgr.getFileManager().getVirtualFileSystem();
+    for (llvm::vfs::recursive_directory_iterator I(FS, Dir->getName(), EC), E;
          I != E && !EC; I.increment(EC)) {
       if (const FileEntry *FE = SourceMgr.getFileManager().getFile(I->path())) {
 

lib/Lex/PPLexerChange.cpp

@@ -304,9 +304,10 @@ void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
 
   ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
   const DirectoryEntry *Dir = Mod.getUmbrellaDir().Entry;
-  vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
+  llvm::vfs::FileSystem &FS = *FileMgr.getVirtualFileSystem();
   std::error_code EC;
-  for (vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC), End;
+  for (llvm::vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC),
+       End;
        Entry != End && !EC; Entry.increment(EC)) {
     using llvm::StringSwitch;
 

lib/Lex/PTHLexer.cpp

@@ -715,8 +715,8 @@ public:
               FL.getBase()) {}
 
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                       std::unique_ptr<vfs::File> *F,
-                       vfs::FileSystem &FS) override {
+                       std::unique_ptr<llvm::vfs::File> *F,
+                       llvm::vfs::FileSystem &FS) override {
     // Do the lookup for the file's data in the PTH file.
     CacheTy::iterator I = Cache.find(Path);
 

lib/Sema/SemaCodeComplete.cpp

@@ -8152,7 +8152,7 @@ void Sema::CodeCompleteIncludedFile(llvm::StringRef Dir, bool Angled) {
     std::error_code EC;
     unsigned Count = 0;
     for (auto It = FS->dir_begin(Dir, EC);
-         !EC && It != vfs::directory_iterator(); It.increment(EC)) {
+         !EC && It != llvm::vfs::directory_iterator(); It.increment(EC)) {
       if (++Count == 2500) // If we happen to hit a huge directory,
         break;             // bail out early so we're not too slow.
       StringRef Filename = llvm::sys::path::filename(It->path());

lib/Serialization/ModuleManager.cpp

@@ -16,7 +16,6 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/MemoryBufferCache.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/PCHContainerOperations.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/ModuleMap.h"
@@ -33,6 +32,7 @@
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/GraphWriter.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <algorithm>
 #include <cassert>
 #include <memory>
@@ -150,7 +150,7 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
 
   if (NewModule->Kind == MK_ImplicitModule) {
     std::string TimestampFilename = NewModule->getTimestampFilename();
-    vfs::Status Status;
+    llvm::vfs::Status Status;
     // A cached stat value would be fine as well.
     if (!FileMgr.getNoncachedStatValue(TimestampFilename, Status))
       NewModule->InputFilesValidationTimestamp =

lib/Tooling/Core/Replacement.cpp

@@ -19,7 +19,6 @@
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Rewrite/Core/RewriteBuffer.h"
 #include "clang/Rewrite/Core/Rewriter.h"
@@ -29,6 +28,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
@@ -583,8 +583,8 @@ llvm::Expected<std::string> applyAllReplacements(StringRef Code,
   if (Replaces.empty())
     return Code.str();
 
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   FileManager Files(FileSystemOptions(), InMemoryFileSystem);
   DiagnosticsEngine Diagnostics(
       IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),

lib/Tooling/StandaloneExecution.cpp

@@ -30,7 +30,7 @@ static ArgumentsAdjuster getDefaultArgumentsAdjusters() {
 StandaloneToolExecutor::StandaloneToolExecutor(
     const CompilationDatabase &Compilations,
     llvm::ArrayRef<std::string> SourcePaths,
-    IntrusiveRefCntPtr<vfs::FileSystem> BaseFS,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps)
     : Tool(Compilations, SourcePaths, std::move(PCHContainerOps),
            std::move(BaseFS)),

lib/Tooling/Tooling.cpp

@@ -19,7 +19,6 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/Job.h"
@@ -51,6 +50,7 @@
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <cstring>
@@ -74,9 +74,9 @@ FrontendActionFactory::~FrontendActionFactory() = default;
 // it to be based on the same framework.
 
 /// Builds a clang driver initialized for running clang tools.
-static driver::Driver *newDriver(
-    DiagnosticsEngine *Diagnostics, const char *BinaryName,
-    IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
+static driver::Driver *
+newDriver(DiagnosticsEngine *Diagnostics, const char *BinaryName,
+          IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   driver::Driver *CompilerDriver =
       new driver::Driver(BinaryName, llvm::sys::getDefaultTargetTriple(),
                          *Diagnostics, std::move(VFS));
@@ -155,7 +155,7 @@ namespace tooling {
 
 bool runToolOnCodeWithArgs(
     FrontendAction *ToolAction, const Twine &Code,
-    llvm::IntrusiveRefCntPtr<vfs::FileSystem> VFS,
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
     const std::vector<std::string> &Args, const Twine &FileName,
     const Twine &ToolName,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
@@ -178,10 +178,10 @@ bool runToolOnCodeWithArgs(
     const Twine &ToolName,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     const FileContentMappings &VirtualMappedFiles) {
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
-      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
 
   SmallString<1024> CodeStorage;
@@ -199,7 +199,7 @@ bool runToolOnCodeWithArgs(
                                FileName, ToolName);
 }
 
-llvm::Expected<std::string> getAbsolutePath(vfs::FileSystem &FS,
+llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
                                             StringRef File) {
   StringRef RelativePath(File);
   // FIXME: Should '.\\' be accepted on Win32?
@@ -215,7 +215,7 @@ llvm::Expected<std::string> getAbsolutePath(vfs::FileSystem &FS,
 }
 
 std::string getAbsolutePath(StringRef File) {
-  return llvm::cantFail(getAbsolutePath(*vfs::getRealFileSystem(), File));
+  return llvm::cantFail(getAbsolutePath(*llvm::vfs::getRealFileSystem(), File));
 }
 
 void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
@@ -372,11 +372,11 @@ bool FrontendActionFactory::runInvocation(
 ClangTool::ClangTool(const CompilationDatabase &Compilations,
                      ArrayRef<std::string> SourcePaths,
                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
-                     IntrusiveRefCntPtr<vfs::FileSystem> BaseFS)
+                     IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS)
     : Compilations(Compilations), SourcePaths(SourcePaths),
       PCHContainerOps(std::move(PCHContainerOps)),
-      OverlayFileSystem(new vfs::OverlayFileSystem(std::move(BaseFS))),
-      InMemoryFileSystem(new vfs::InMemoryFileSystem),
+      OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
+      InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
       Files(new FileManager(FileSystemOptions(), OverlayFileSystem)) {
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   appendArgumentsAdjuster(getClangStripOutputAdjuster());
@@ -586,10 +586,10 @@ std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
 
   std::vector<std::unique_ptr<ASTUnit>> ASTs;
   ASTBuilderAction Action(ASTs);
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
-      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   llvm::IntrusiveRefCntPtr<FileManager> Files(
       new FileManager(FileSystemOptions(), OverlayFileSystem));

tools/clang-format/ClangFormat.cpp

@@ -116,7 +116,7 @@ namespace format {
 
 static FileID createInMemoryFile(StringRef FileName, MemoryBuffer *Source,
                                  SourceManager &Sources, FileManager &Files,
-                                 vfs::InMemoryFileSystem *MemFS) {
+                                 llvm::vfs::InMemoryFileSystem *MemFS) {
   MemFS->addFileNoOwn(FileName, 0, Source);
   return Sources.createFileID(Files.getFile(FileName), SourceLocation(),
                               SrcMgr::C_User);
@@ -133,8 +133,8 @@ static bool parseLineRange(StringRef Input, unsigned &FromLine,
 
 static bool fillRanges(MemoryBuffer *Code,
                        std::vector<tooling::Range> &Ranges) {
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   FileManager Files(FileSystemOptions(), InMemoryFileSystem);
   DiagnosticsEngine Diagnostics(
       IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),
@@ -301,8 +301,8 @@ static bool format(StringRef FileName) {
     outputReplacementsXML(Replaces);
     outs() << "</replacements>\n";
   } else {
-    IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-        new vfs::InMemoryFileSystem);
+    IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+        new llvm::vfs::InMemoryFileSystem);
     FileManager Files(FileSystemOptions(), InMemoryFileSystem);
     DiagnosticsEngine Diagnostics(
         IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),

tools/driver/cc1gen_reproducer_main.cpp

@@ -14,13 +14,13 @@
 
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
 

tools/libclang/BuildSystem.cpp

@@ -13,12 +13,12 @@
 
 #include "clang-c/BuildSystem.h"
 #include "CXString.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace clang;
@@ -28,11 +28,11 @@ unsigned long long clang_getBuildSessionTimestamp(void) {
   return llvm::sys::toTimeT(std::chrono::system_clock::now());
 }
 
-DEFINE_SIMPLE_CONVERSION_FUNCTIONS(clang::vfs::YAMLVFSWriter,
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(llvm::vfs::YAMLVFSWriter,
                                    CXVirtualFileOverlay)
 
 CXVirtualFileOverlay clang_VirtualFileOverlay_create(unsigned) {
-  return wrap(new clang::vfs::YAMLVFSWriter());
+  return wrap(new llvm::vfs::YAMLVFSWriter());
 }
 
 enum CXErrorCode

unittests/AST/ASTImporterTest.cpp

@@ -37,10 +37,10 @@ createVirtualFileIfNeeded(ASTUnit *ToAST, StringRef FileName,
                           std::unique_ptr<llvm::MemoryBuffer> &&Buffer) {
   assert(ToAST);
   ASTContext &ToCtx = ToAST->getASTContext();
-  auto *OFS = static_cast<vfs::OverlayFileSystem *>(
+  auto *OFS = static_cast<llvm::vfs::OverlayFileSystem *>(
       ToCtx.getSourceManager().getFileManager().getVirtualFileSystem().get());
-  auto *MFS =
-      static_cast<vfs::InMemoryFileSystem *>(OFS->overlays_begin()->get());
+  auto *MFS = static_cast<llvm::vfs::InMemoryFileSystem *>(
+      OFS->overlays_begin()->get());
   MFS->addFile(FileName, 0, std::move(Buffer));
 }
 
@@ -2482,7 +2482,7 @@ TEST_P(ImportFriendFunctions, ImportFriendChangesLookup) {
   LookupRes = ToTU->noload_lookup(ToName);
   EXPECT_EQ(LookupRes.size(), 1u);
   EXPECT_EQ(DeclCounter<FunctionDecl>().match(ToTU, Pattern), 1u);
-  
+
   auto *ToFriendF = cast<FunctionDecl>(Import(FromFriendF, Lang_CXX));
   LookupRes = ToTU->noload_lookup(ToName);
   EXPECT_EQ(LookupRes.size(), 1u);
@@ -2758,7 +2758,7 @@ TEST_P(ASTImporterTestBase, ImportOfEquivalentRecord) {
 
     ToR2 = Import(FromR, Lang_CXX);
   }
-  
+
   EXPECT_EQ(ToR1, ToR2);
 }
 

unittests/AST/CommentTextTest.cpp

@@ -20,8 +20,8 @@
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <gtest/gtest.h>
 
 namespace clang {

unittests/Basic/CMakeLists.txt

@@ -9,7 +9,6 @@ add_clang_unittest(BasicTests
   FixedPointTest.cpp
   MemoryBufferCacheTest.cpp
   SourceManagerTest.cpp
-  VirtualFileSystemTest.cpp
   )
 
 target_link_libraries(BasicTests

unittests/Basic/FileManagerTest.cpp

@@ -10,9 +10,9 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/FileSystemStatCache.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -60,8 +60,8 @@ public:
 
   // Implement FileSystemStatCache::getStat().
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
-                       std::unique_ptr<vfs::File> *F,
-                       vfs::FileSystem &FS) override {
+                       std::unique_ptr<llvm::vfs::File> *F,
+                       llvm::vfs::FileSystem &FS) override {
 #ifndef _WIN32
     SmallString<128> NormalizedPath(Path);
     llvm::sys::path::native(NormalizedPath);
@@ -305,8 +305,8 @@ TEST_F(FileManagerTest, makeAbsoluteUsesVFS) {
 #endif
   llvm::sys::path::append(CustomWorkingDir, "some", "weird", "path");
 
-  auto FS =
-      IntrusiveRefCntPtr<vfs::InMemoryFileSystem>(new vfs::InMemoryFileSystem);
+  auto FS = IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem>(
+      new llvm::vfs::InMemoryFileSystem);
   // setCurrentworkingdirectory must finish without error.
   ASSERT_TRUE(!FS->setCurrentWorkingDirectory(CustomWorkingDir));
 

unittests/Basic/VirtualFileSystemTest.cpp

@@ -1,1592 +0,0 @@
-//===- unittests/Basic/VirtualFileSystem.cpp ---------------- VFS tests ---===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Basic/VirtualFileSystem.h"
-#include "llvm/ADT/Triple.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/Support/Errc.h"
-#include "llvm/Support/Host.h"
-#include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/Path.h"
-#include "llvm/Support/SourceMgr.h"
-#include "gmock/gmock.h"
-#include "gtest/gtest.h"
-#include <map>
-#include <string>
-
-using namespace clang;
-using namespace llvm;
-using llvm::sys::fs::UniqueID;
-using testing::ElementsAre;
-using testing::Pair;
-using testing::UnorderedElementsAre;
-
-namespace {
-struct DummyFile : public vfs::File {
-  vfs::Status S;
-  explicit DummyFile(vfs::Status S) : S(S) {}
-  llvm::ErrorOr<vfs::Status> status() override { return S; }
-  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
-  getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
-            bool IsVolatile) override {
-    llvm_unreachable("unimplemented");
-  }
-  std::error_code close() override { return std::error_code(); }
-};
-
-class DummyFileSystem : public vfs::FileSystem {
-  int FSID;   // used to produce UniqueIDs
-  int FileID; // used to produce UniqueIDs
-  std::map<std::string, vfs::Status> FilesAndDirs;
-
-  static int getNextFSID() {
-    static int Count = 0;
-    return Count++;
-  }
-
-public:
-  DummyFileSystem() : FSID(getNextFSID()), FileID(0) {}
-
-  ErrorOr<vfs::Status> status(const Twine &Path) override {
-    std::map<std::string, vfs::Status>::iterator I =
-        FilesAndDirs.find(Path.str());
-    if (I == FilesAndDirs.end())
-      return make_error_code(llvm::errc::no_such_file_or_directory);
-    return I->second;
-  }
-  ErrorOr<std::unique_ptr<vfs::File>>
-  openFileForRead(const Twine &Path) override {
-    auto S = status(Path);
-    if (S)
-      return std::unique_ptr<vfs::File>(new DummyFile{*S});
-    return S.getError();
-  }
-  llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
-    return std::string();
-  }
-  std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
-    return std::error_code();
-  }
-  // Map any symlink to "/symlink".
-  std::error_code getRealPath(const Twine &Path,
-                              SmallVectorImpl<char> &Output) const override {
-    auto I = FilesAndDirs.find(Path.str());
-    if (I == FilesAndDirs.end())
-      return make_error_code(llvm::errc::no_such_file_or_directory);
-    if (I->second.isSymlink()) {
-      Output.clear();
-      Twine("/symlink").toVector(Output);
-      return std::error_code();
-    }
-    Output.clear();
-    Path.toVector(Output);
-    return std::error_code();
-  }
-
-  struct DirIterImpl : public clang::vfs::detail::DirIterImpl {
-    std::map<std::string, vfs::Status> &FilesAndDirs;
-    std::map<std::string, vfs::Status>::iterator I;
-    std::string Path;
-    bool isInPath(StringRef S) {
-      if (Path.size() < S.size() && S.find(Path) == 0) {
-        auto LastSep = S.find_last_of('/');
-        if (LastSep == Path.size() || LastSep == Path.size()-1)
-          return true;
-      }
-      return false;
-    }
-    DirIterImpl(std::map<std::string, vfs::Status> &FilesAndDirs,
-                const Twine &_Path)
-        : FilesAndDirs(FilesAndDirs), I(FilesAndDirs.begin()),
-          Path(_Path.str()) {
-      for ( ; I != FilesAndDirs.end(); ++I) {
-        if (isInPath(I->first)) {
-          CurrentEntry =
-              vfs::directory_entry(I->second.getName(), I->second.getType());
-          break;
-        }
-      }
-    }
-    std::error_code increment() override {
-      ++I;
-      for ( ; I != FilesAndDirs.end(); ++I) {
-        if (isInPath(I->first)) {
-          CurrentEntry =
-              vfs::directory_entry(I->second.getName(), I->second.getType());
-          break;
-        }
-      }
-      if (I == FilesAndDirs.end())
-        CurrentEntry = vfs::directory_entry();
-      return std::error_code();
-    }
-  };
-
-  vfs::directory_iterator dir_begin(const Twine &Dir,
-                                    std::error_code &EC) override {
-    return vfs::directory_iterator(
-        std::make_shared<DirIterImpl>(FilesAndDirs, Dir));
-  }
-
-  void addEntry(StringRef Path, const vfs::Status &Status) {
-    FilesAndDirs[Path] = Status;
-  }
-
-  void addRegularFile(StringRef Path, sys::fs::perms Perms = sys::fs::all_all) {
-    vfs::Status S(Path, UniqueID(FSID, FileID++),
-                  std::chrono::system_clock::now(), 0, 0, 1024,
-                  sys::fs::file_type::regular_file, Perms);
-    addEntry(Path, S);
-  }
-
-  void addDirectory(StringRef Path, sys::fs::perms Perms = sys::fs::all_all) {
-    vfs::Status S(Path, UniqueID(FSID, FileID++),
-                  std::chrono::system_clock::now(), 0, 0, 0,
-                  sys::fs::file_type::directory_file, Perms);
-    addEntry(Path, S);
-  }
-
-  void addSymlink(StringRef Path) {
-    vfs::Status S(Path, UniqueID(FSID, FileID++),
-                  std::chrono::system_clock::now(), 0, 0, 0,
-                  sys::fs::file_type::symlink_file, sys::fs::all_all);
-    addEntry(Path, S);
-  }
-};
-
-/// Replace back-slashes by front-slashes.
-std::string getPosixPath(std::string S) {
-  SmallString<128> Result;
-  llvm::sys::path::native(S, Result, llvm::sys::path::Style::posix);
-  return Result.str();
-}
-} // end anonymous namespace
-
-TEST(VirtualFileSystemTest, StatusQueries) {
-  IntrusiveRefCntPtr<DummyFileSystem> D(new DummyFileSystem());
-  ErrorOr<vfs::Status> Status((std::error_code()));
-
-  D->addRegularFile("/foo");
-  Status = D->status("/foo");
-  ASSERT_FALSE(Status.getError());
-  EXPECT_TRUE(Status->isStatusKnown());
-  EXPECT_FALSE(Status->isDirectory());
-  EXPECT_TRUE(Status->isRegularFile());
-  EXPECT_FALSE(Status->isSymlink());
-  EXPECT_FALSE(Status->isOther());
-  EXPECT_TRUE(Status->exists());
-
-  D->addDirectory("/bar");
-  Status = D->status("/bar");
-  ASSERT_FALSE(Status.getError());
-  EXPECT_TRUE(Status->isStatusKnown());
-  EXPECT_TRUE(Status->isDirectory());
-  EXPECT_FALSE(Status->isRegularFile());
-  EXPECT_FALSE(Status->isSymlink());
-  EXPECT_FALSE(Status->isOther());
-  EXPECT_TRUE(Status->exists());
-
-  D->addSymlink("/baz");
-  Status = D->status("/baz");
-  ASSERT_FALSE(Status.getError());
-  EXPECT_TRUE(Status->isStatusKnown());
-  EXPECT_FALSE(Status->isDirectory());
-  EXPECT_FALSE(Status->isRegularFile());
-  EXPECT_TRUE(Status->isSymlink());
-  EXPECT_FALSE(Status->isOther());
-  EXPECT_TRUE(Status->exists());
-
-  EXPECT_TRUE(Status->equivalent(*Status));
-  ErrorOr<vfs::Status> Status2 = D->status("/foo");
-  ASSERT_FALSE(Status2.getError());
-  EXPECT_FALSE(Status->equivalent(*Status2));
-}
-
-TEST(VirtualFileSystemTest, BaseOnlyOverlay) {
-  IntrusiveRefCntPtr<DummyFileSystem> D(new DummyFileSystem());
-  ErrorOr<vfs::Status> Status((std::error_code()));
-  EXPECT_FALSE(Status = D->status("/foo"));
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(new vfs::OverlayFileSystem(D));
-  EXPECT_FALSE(Status = O->status("/foo"));
-
-  D->addRegularFile("/foo");
-  Status = D->status("/foo");
-  EXPECT_FALSE(Status.getError());
-
-  ErrorOr<vfs::Status> Status2((std::error_code()));
-  Status2 = O->status("/foo");
-  EXPECT_FALSE(Status2.getError());
-  EXPECT_TRUE(Status->equivalent(*Status2));
-}
-
-TEST(VirtualFileSystemTest, GetRealPathInOverlay) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("/foo");
-  Lower->addSymlink("/lower_link");
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Upper);
-
-  // Regular file.
-  SmallString<16> RealPath;
-  EXPECT_FALSE(O->getRealPath("/foo", RealPath));
-  EXPECT_EQ(RealPath.str(), "/foo");
-
-  // Expect no error getting real path for symlink in lower overlay.
-  EXPECT_FALSE(O->getRealPath("/lower_link", RealPath));
-  EXPECT_EQ(RealPath.str(), "/symlink");
-
-  // Try a non-existing link.
-  EXPECT_EQ(O->getRealPath("/upper_link", RealPath),
-            errc::no_such_file_or_directory);
-
-  // Add a new symlink in upper.
-  Upper->addSymlink("/upper_link");
-  EXPECT_FALSE(O->getRealPath("/upper_link", RealPath));
-  EXPECT_EQ(RealPath.str(), "/symlink");
-}
-
-TEST(VirtualFileSystemTest, OverlayFiles) {
-  IntrusiveRefCntPtr<DummyFileSystem> Base(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Top(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Base));
-  O->pushOverlay(Middle);
-  O->pushOverlay(Top);
-
-  ErrorOr<vfs::Status> Status1((std::error_code())),
-      Status2((std::error_code())), Status3((std::error_code())),
-      StatusB((std::error_code())), StatusM((std::error_code())),
-      StatusT((std::error_code()));
-
-  Base->addRegularFile("/foo");
-  StatusB = Base->status("/foo");
-  ASSERT_FALSE(StatusB.getError());
-  Status1 = O->status("/foo");
-  ASSERT_FALSE(Status1.getError());
-  Middle->addRegularFile("/foo");
-  StatusM = Middle->status("/foo");
-  ASSERT_FALSE(StatusM.getError());
-  Status2 = O->status("/foo");
-  ASSERT_FALSE(Status2.getError());
-  Top->addRegularFile("/foo");
-  StatusT = Top->status("/foo");
-  ASSERT_FALSE(StatusT.getError());
-  Status3 = O->status("/foo");
-  ASSERT_FALSE(Status3.getError());
-
-  EXPECT_TRUE(Status1->equivalent(*StatusB));
-  EXPECT_TRUE(Status2->equivalent(*StatusM));
-  EXPECT_TRUE(Status3->equivalent(*StatusT));
-
-  EXPECT_FALSE(Status1->equivalent(*Status2));
-  EXPECT_FALSE(Status2->equivalent(*Status3));
-  EXPECT_FALSE(Status1->equivalent(*Status3));
-}
-
-TEST(VirtualFileSystemTest, OverlayDirsNonMerged) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Upper);
-
-  Lower->addDirectory("/lower-only");
-  Upper->addDirectory("/upper-only");
-
-  // non-merged paths should be the same
-  ErrorOr<vfs::Status> Status1 = Lower->status("/lower-only");
-  ASSERT_FALSE(Status1.getError());
-  ErrorOr<vfs::Status> Status2 = O->status("/lower-only");
-  ASSERT_FALSE(Status2.getError());
-  EXPECT_TRUE(Status1->equivalent(*Status2));
-
-  Status1 = Upper->status("/upper-only");
-  ASSERT_FALSE(Status1.getError());
-  Status2 = O->status("/upper-only");
-  ASSERT_FALSE(Status2.getError());
-  EXPECT_TRUE(Status1->equivalent(*Status2));
-}
-
-TEST(VirtualFileSystemTest, MergedDirPermissions) {
-  // merged directories get the permissions of the upper dir
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Upper);
-
-  ErrorOr<vfs::Status> Status((std::error_code()));
-  Lower->addDirectory("/both", sys::fs::owner_read);
-  Upper->addDirectory("/both", sys::fs::owner_all | sys::fs::group_read);
-  Status = O->status("/both");
-  ASSERT_FALSE(Status.getError());
-  EXPECT_EQ(0740, Status->getPermissions());
-
-  // permissions (as usual) are not recursively applied
-  Lower->addRegularFile("/both/foo", sys::fs::owner_read);
-  Upper->addRegularFile("/both/bar", sys::fs::owner_write);
-  Status = O->status("/both/foo");
-  ASSERT_FALSE( Status.getError());
-  EXPECT_EQ(0400, Status->getPermissions());
-  Status = O->status("/both/bar");
-  ASSERT_FALSE(Status.getError());
-  EXPECT_EQ(0200, Status->getPermissions());
-}
-
-namespace {
-struct ScopedDir {
-  SmallString<128> Path;
-  ScopedDir(const Twine &Name, bool Unique=false) {
-    std::error_code EC;
-    if (Unique) {
-      EC =  llvm::sys::fs::createUniqueDirectory(Name, Path);
-    } else {
-      Path = Name.str();
-      EC = llvm::sys::fs::create_directory(Twine(Path));
-    }
-    if (EC)
-      Path = "";
-    EXPECT_FALSE(EC);
-  }
-  ~ScopedDir() {
-    if (Path != "") {
-      EXPECT_FALSE(llvm::sys::fs::remove(Path.str()));
-    }
-  }
-  operator StringRef() { return Path.str(); }
-};
-
-struct ScopedLink {
-  SmallString<128> Path;
-  ScopedLink(const Twine &To, const Twine &From) {
-    Path = From.str();
-    std::error_code EC = sys::fs::create_link(To, From);
-    if (EC)
-      Path = "";
-    EXPECT_FALSE(EC);
-  }
-  ~ScopedLink() {
-    if (Path != "") {
-      EXPECT_FALSE(llvm::sys::fs::remove(Path.str()));
-    }
-  }
-  operator StringRef() { return Path.str(); }
-};
-} // end anonymous namespace
-
-TEST(VirtualFileSystemTest, BasicRealFSIteration) {
-  ScopedDir TestDirectory("virtual-file-system-test", /*Unique*/true);
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();
-
-  std::error_code EC;
-  vfs::directory_iterator I = FS->dir_begin(Twine(TestDirectory), EC);
-  ASSERT_FALSE(EC);
-  EXPECT_EQ(vfs::directory_iterator(), I); // empty directory is empty
-
-  ScopedDir _a(TestDirectory+"/a");
-  ScopedDir _ab(TestDirectory+"/a/b");
-  ScopedDir _c(TestDirectory+"/c");
-  ScopedDir _cd(TestDirectory+"/c/d");
-
-  I = FS->dir_begin(Twine(TestDirectory), EC);
-  ASSERT_FALSE(EC);
-  ASSERT_NE(vfs::directory_iterator(), I);
-  // Check either a or c, since we can't rely on the iteration order.
-  EXPECT_TRUE(I->path().endswith("a") || I->path().endswith("c"));
-  I.increment(EC);
-  ASSERT_FALSE(EC);
-  ASSERT_NE(vfs::directory_iterator(), I);
-  EXPECT_TRUE(I->path().endswith("a") || I->path().endswith("c"));
-  I.increment(EC);
-  EXPECT_EQ(vfs::directory_iterator(), I);
-}
-
-#ifdef LLVM_ON_UNIX
-TEST(VirtualFileSystemTest, BrokenSymlinkRealFSIteration) {
-  ScopedDir TestDirectory("virtual-file-system-test", /*Unique*/ true);
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();
-
-  ScopedLink _a("no_such_file", TestDirectory + "/a");
-  ScopedDir _b(TestDirectory + "/b");
-  ScopedLink _c("no_such_file", TestDirectory + "/c");
-
-  // Should get no iteration error, but a stat error for the broken symlinks.
-  std::map<std::string, std::error_code> StatResults;
-  std::error_code EC;
-  for (vfs::directory_iterator I = FS->dir_begin(Twine(TestDirectory), EC), E;
-       I != E; I.increment(EC)) {
-    EXPECT_FALSE(EC);
-    StatResults[sys::path::filename(I->path())] =
-        FS->status(I->path()).getError();
-  }
-  EXPECT_THAT(
-      StatResults,
-      ElementsAre(
-          Pair("a", std::make_error_code(std::errc::no_such_file_or_directory)),
-          Pair("b", std::error_code()),
-          Pair("c",
-               std::make_error_code(std::errc::no_such_file_or_directory))));
-}
-#endif
-
-TEST(VirtualFileSystemTest, BasicRealFSRecursiveIteration) {
-  ScopedDir TestDirectory("virtual-file-system-test", /*Unique*/true);
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();
-
-  std::error_code EC;
-  auto I = vfs::recursive_directory_iterator(*FS, Twine(TestDirectory), EC);
-  ASSERT_FALSE(EC);
-  EXPECT_EQ(vfs::recursive_directory_iterator(), I); // empty directory is empty
-
-  ScopedDir _a(TestDirectory+"/a");
-  ScopedDir _ab(TestDirectory+"/a/b");
-  ScopedDir _c(TestDirectory+"/c");
-  ScopedDir _cd(TestDirectory+"/c/d");
-
-  I = vfs::recursive_directory_iterator(*FS, Twine(TestDirectory), EC);
-  ASSERT_FALSE(EC);
-  ASSERT_NE(vfs::recursive_directory_iterator(), I);
-
-  std::vector<std::string> Contents;
-  for (auto E = vfs::recursive_directory_iterator(); !EC && I != E;
-       I.increment(EC)) {
-    Contents.push_back(I->path());
-  }
-
-  // Check contents, which may be in any order
-  EXPECT_EQ(4U, Contents.size());
-  int Counts[4] = { 0, 0, 0, 0 };
-  for (const std::string &Name : Contents) {
-    ASSERT_FALSE(Name.empty());
-    int Index = Name[Name.size()-1] - 'a';
-    ASSERT_TRUE(Index >= 0 && Index < 4);
-    Counts[Index]++;
-  }
-  EXPECT_EQ(1, Counts[0]); // a
-  EXPECT_EQ(1, Counts[1]); // b
-  EXPECT_EQ(1, Counts[2]); // c
-  EXPECT_EQ(1, Counts[3]); // d
-}
-
-#ifdef LLVM_ON_UNIX
-TEST(VirtualFileSystemTest, BrokenSymlinkRealFSRecursiveIteration) {
-  ScopedDir TestDirectory("virtual-file-system-test", /*Unique*/ true);
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();
-
-  ScopedLink _a("no_such_file", TestDirectory + "/a");
-  ScopedDir _b(TestDirectory + "/b");
-  ScopedLink _ba("no_such_file", TestDirectory + "/b/a");
-  ScopedDir _bb(TestDirectory + "/b/b");
-  ScopedLink _bc("no_such_file", TestDirectory + "/b/c");
-  ScopedLink _c("no_such_file", TestDirectory + "/c");
-  ScopedDir _d(TestDirectory + "/d");
-  ScopedDir _dd(TestDirectory + "/d/d");
-  ScopedDir _ddd(TestDirectory + "/d/d/d");
-  ScopedLink _e("no_such_file", TestDirectory + "/e");
-
-  std::vector<std::string> VisitedBrokenSymlinks;
-  std::vector<std::string> VisitedNonBrokenSymlinks;
-  std::error_code EC;
-  for (vfs::recursive_directory_iterator I(*FS, Twine(TestDirectory), EC), E;
-       I != E; I.increment(EC)) {
-    EXPECT_FALSE(EC);
-    (FS->status(I->path()) ? VisitedNonBrokenSymlinks : VisitedBrokenSymlinks)
-        .push_back(I->path());
-  }
-
-  // Check visited file names.
-  EXPECT_THAT(VisitedBrokenSymlinks,
-              UnorderedElementsAre(StringRef(_a), StringRef(_ba),
-                                   StringRef(_bc), StringRef(_c),
-                                   StringRef(_e)));
-  EXPECT_THAT(VisitedNonBrokenSymlinks,
-              UnorderedElementsAre(StringRef(_b), StringRef(_bb), StringRef(_d),
-                                   StringRef(_dd), StringRef(_ddd)));
-}
-#endif
-
-template <typename DirIter>
-static void checkContents(DirIter I, ArrayRef<StringRef> ExpectedOut) {
-  std::error_code EC;
-  SmallVector<StringRef, 4> Expected(ExpectedOut.begin(), ExpectedOut.end());
-  SmallVector<std::string, 4> InputToCheck;
-
-  // Do not rely on iteration order to check for contents, sort both
-  // content vectors before comparison.
-  for (DirIter E; !EC && I != E; I.increment(EC))
-    InputToCheck.push_back(I->path());
-
-  llvm::sort(InputToCheck);
-  llvm::sort(Expected);
-  EXPECT_EQ(InputToCheck.size(), Expected.size());
-
-  unsigned LastElt = std::min(InputToCheck.size(), Expected.size());
-  for (unsigned Idx = 0; Idx != LastElt; ++Idx)
-    EXPECT_EQ(StringRef(InputToCheck[Idx]), Expected[Idx]);
-}
-
-TEST(VirtualFileSystemTest, OverlayIteration) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Upper);
-
-  std::error_code EC;
-  checkContents(O->dir_begin("/", EC), ArrayRef<StringRef>());
-
-  Lower->addRegularFile("/file1");
-  checkContents(O->dir_begin("/", EC), ArrayRef<StringRef>("/file1"));
-
-  Upper->addRegularFile("/file2");
-  checkContents(O->dir_begin("/", EC), {"/file2", "/file1"});
-
-  Lower->addDirectory("/dir1");
-  Lower->addRegularFile("/dir1/foo");
-  Upper->addDirectory("/dir2");
-  Upper->addRegularFile("/dir2/foo");
-  checkContents(O->dir_begin("/dir2", EC), ArrayRef<StringRef>("/dir2/foo"));
-  checkContents(O->dir_begin("/", EC), {"/dir2", "/file2", "/dir1", "/file1"});
-}
-
-TEST(VirtualFileSystemTest, OverlayRecursiveIteration) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Middle);
-  O->pushOverlay(Upper);
-
-  std::error_code EC;
-  checkContents(vfs::recursive_directory_iterator(*O, "/", EC),
-                ArrayRef<StringRef>());
-
-  Lower->addRegularFile("/file1");
-  checkContents(vfs::recursive_directory_iterator(*O, "/", EC),
-                ArrayRef<StringRef>("/file1"));
-
-  Upper->addDirectory("/dir");
-  Upper->addRegularFile("/dir/file2");
-  checkContents(vfs::recursive_directory_iterator(*O, "/", EC),
-                {"/dir", "/dir/file2", "/file1"});
-
-  Lower->addDirectory("/dir1");
-  Lower->addRegularFile("/dir1/foo");
-  Lower->addDirectory("/dir1/a");
-  Lower->addRegularFile("/dir1/a/b");
-  Middle->addDirectory("/a");
-  Middle->addDirectory("/a/b");
-  Middle->addDirectory("/a/b/c");
-  Middle->addRegularFile("/a/b/c/d");
-  Middle->addRegularFile("/hiddenByUp");
-  Upper->addDirectory("/dir2");
-  Upper->addRegularFile("/dir2/foo");
-  Upper->addRegularFile("/hiddenByUp");
-  checkContents(vfs::recursive_directory_iterator(*O, "/dir2", EC),
-                ArrayRef<StringRef>("/dir2/foo"));
-  checkContents(vfs::recursive_directory_iterator(*O, "/", EC),
-                {"/dir", "/dir/file2", "/dir2", "/dir2/foo", "/hiddenByUp",
-                 "/a", "/a/b", "/a/b/c", "/a/b/c/d", "/dir1", "/dir1/a",
-                 "/dir1/a/b", "/dir1/foo", "/file1"});
-}
-
-TEST(VirtualFileSystemTest, ThreeLevelIteration) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Middle);
-  O->pushOverlay(Upper);
-
-  std::error_code EC;
-  checkContents(O->dir_begin("/", EC), ArrayRef<StringRef>());
-
-  Middle->addRegularFile("/file2");
-  checkContents(O->dir_begin("/", EC), ArrayRef<StringRef>("/file2"));
-
-  Lower->addRegularFile("/file1");
-  Upper->addRegularFile("/file3");
-  checkContents(O->dir_begin("/", EC), {"/file3", "/file2", "/file1"});
-}
-
-TEST(VirtualFileSystemTest, HiddenInIteration) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
-  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(Middle);
-  O->pushOverlay(Upper);
-
-  std::error_code EC;
-  Lower->addRegularFile("/onlyInLow");
-  Lower->addDirectory("/hiddenByMid");
-  Lower->addDirectory("/hiddenByUp");
-  Middle->addRegularFile("/onlyInMid");
-  Middle->addRegularFile("/hiddenByMid");
-  Middle->addDirectory("/hiddenByUp");
-  Upper->addRegularFile("/onlyInUp");
-  Upper->addRegularFile("/hiddenByUp");
-  checkContents(
-      O->dir_begin("/", EC),
-      {"/hiddenByUp", "/onlyInUp", "/hiddenByMid", "/onlyInMid", "/onlyInLow"});
-
-  // Make sure we get the top-most entry
-  {
-    std::error_code EC;
-    vfs::directory_iterator I = O->dir_begin("/", EC), E;
-    for ( ; !EC && I != E; I.increment(EC))
-      if (I->path() == "/hiddenByUp")
-        break;
-    ASSERT_NE(E, I);
-    EXPECT_EQ(sys::fs::file_type::regular_file, I->type());
-  }
-  {
-    std::error_code EC;
-    vfs::directory_iterator I = O->dir_begin("/", EC), E;
-    for ( ; !EC && I != E; I.increment(EC))
-      if (I->path() == "/hiddenByMid")
-        break;
-    ASSERT_NE(E, I);
-    EXPECT_EQ(sys::fs::file_type::regular_file, I->type());
-  }
-}
-
-class InMemoryFileSystemTest : public ::testing::Test {
-protected:
-  clang::vfs::InMemoryFileSystem FS;
-  clang::vfs::InMemoryFileSystem NormalizedFS;
-
-  InMemoryFileSystemTest()
-      : FS(/*UseNormalizedPaths=*/false),
-        NormalizedFS(/*UseNormalizedPaths=*/true) {}
-};
-
-MATCHER_P2(IsHardLinkTo, FS, Target, "") {
-  StringRef From = arg;
-  StringRef To = Target;
-  auto OpenedFrom = FS->openFileForRead(From);
-  auto OpenedTo = FS->openFileForRead(To);
-  return !OpenedFrom.getError() && !OpenedTo.getError() &&
-         (*OpenedFrom)->status()->getUniqueID() ==
-             (*OpenedTo)->status()->getUniqueID();
-}
-
-TEST_F(InMemoryFileSystemTest, IsEmpty) {
-  auto Stat = FS.status("/a");
-  ASSERT_EQ(Stat.getError(),errc::no_such_file_or_directory) << FS.toString();
-  Stat = FS.status("/");
-  ASSERT_EQ(Stat.getError(), errc::no_such_file_or_directory) << FS.toString();
-}
-
-TEST_F(InMemoryFileSystemTest, WindowsPath) {
-  FS.addFile("c:/windows/system128/foo.cpp", 0, MemoryBuffer::getMemBuffer(""));
-  auto Stat = FS.status("c:");
-#if !defined(_WIN32)
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << FS.toString();
-#endif
-  Stat = FS.status("c:/windows/system128/foo.cpp");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << FS.toString();
-  FS.addFile("d:/windows/foo.cpp", 0, MemoryBuffer::getMemBuffer(""));
-  Stat = FS.status("d:/windows/foo.cpp");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << FS.toString();
-}
-
-TEST_F(InMemoryFileSystemTest, OverlayFile) {
-  FS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a"));
-  NormalizedFS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a"));
-  auto Stat = FS.status("/");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << FS.toString();
-  Stat = FS.status("/.");
-  ASSERT_FALSE(Stat);
-  Stat = NormalizedFS.status("/.");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << FS.toString();
-  Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_EQ("/a", Stat->getName());
-}
-
-TEST_F(InMemoryFileSystemTest, OverlayFileNoOwn) {
-  auto Buf = MemoryBuffer::getMemBuffer("a");
-  FS.addFileNoOwn("/a", 0, Buf.get());
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_EQ("/a", Stat->getName());
-}
-
-TEST_F(InMemoryFileSystemTest, OpenFileForRead) {
-  FS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a"));
-  FS.addFile("././c", 0, MemoryBuffer::getMemBuffer("c"));
-  FS.addFile("./d/../d", 0, MemoryBuffer::getMemBuffer("d"));
-  NormalizedFS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a"));
-  NormalizedFS.addFile("././c", 0, MemoryBuffer::getMemBuffer("c"));
-  NormalizedFS.addFile("./d/../d", 0, MemoryBuffer::getMemBuffer("d"));
-  auto File = FS.openFileForRead("/a");
-  ASSERT_EQ("a", (*(*File)->getBuffer("ignored"))->getBuffer());
-  File = FS.openFileForRead("/a"); // Open again.
-  ASSERT_EQ("a", (*(*File)->getBuffer("ignored"))->getBuffer());
-  File = NormalizedFS.openFileForRead("/././a"); // Open again.
-  ASSERT_EQ("a", (*(*File)->getBuffer("ignored"))->getBuffer());
-  File = FS.openFileForRead("/");
-  ASSERT_EQ(File.getError(), errc::invalid_argument) << FS.toString();
-  File = FS.openFileForRead("/b");
-  ASSERT_EQ(File.getError(), errc::no_such_file_or_directory) << FS.toString();
-  File = FS.openFileForRead("./c");
-  ASSERT_FALSE(File);
-  File = FS.openFileForRead("e/../d");
-  ASSERT_FALSE(File);
-  File = NormalizedFS.openFileForRead("./c");
-  ASSERT_EQ("c", (*(*File)->getBuffer("ignored"))->getBuffer());
-  File = NormalizedFS.openFileForRead("e/../d");
-  ASSERT_EQ("d", (*(*File)->getBuffer("ignored"))->getBuffer());
-}
-
-TEST_F(InMemoryFileSystemTest, DuplicatedFile) {
-  ASSERT_TRUE(FS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a")));
-  ASSERT_FALSE(FS.addFile("/a/b", 0, MemoryBuffer::getMemBuffer("a")));
-  ASSERT_TRUE(FS.addFile("/a", 0, MemoryBuffer::getMemBuffer("a")));
-  ASSERT_FALSE(FS.addFile("/a", 0, MemoryBuffer::getMemBuffer("b")));
-}
-
-TEST_F(InMemoryFileSystemTest, DirectoryIteration) {
-  FS.addFile("/a", 0, MemoryBuffer::getMemBuffer(""));
-  FS.addFile("/b/c", 0, MemoryBuffer::getMemBuffer(""));
-
-  std::error_code EC;
-  vfs::directory_iterator I = FS.dir_begin("/", EC);
-  ASSERT_FALSE(EC);
-  ASSERT_EQ("/a", I->path());
-  I.increment(EC);
-  ASSERT_FALSE(EC);
-  ASSERT_EQ("/b", I->path());
-  I.increment(EC);
-  ASSERT_FALSE(EC);
-  ASSERT_EQ(vfs::directory_iterator(), I);
-
-  I = FS.dir_begin("/b", EC);
-  ASSERT_FALSE(EC);
-  // When on Windows, we end up with "/b\\c" as the name.  Convert to Posix
-  // path for the sake of the comparison.
-  ASSERT_EQ("/b/c", getPosixPath(I->path()));
-  I.increment(EC);
-  ASSERT_FALSE(EC);
-  ASSERT_EQ(vfs::directory_iterator(), I);
-}
-
-TEST_F(InMemoryFileSystemTest, WorkingDirectory) {
-  FS.setCurrentWorkingDirectory("/b");
-  FS.addFile("c", 0, MemoryBuffer::getMemBuffer(""));
-
-  auto Stat = FS.status("/b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_EQ("/b/c", Stat->getName());
-  ASSERT_EQ("/b", *FS.getCurrentWorkingDirectory());
-
-  Stat = FS.status("c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-
-  NormalizedFS.setCurrentWorkingDirectory("/b/c");
-  NormalizedFS.setCurrentWorkingDirectory(".");
-  ASSERT_EQ("/b/c",
-            getPosixPath(NormalizedFS.getCurrentWorkingDirectory().get()));
-  NormalizedFS.setCurrentWorkingDirectory("..");
-  ASSERT_EQ("/b",
-            getPosixPath(NormalizedFS.getCurrentWorkingDirectory().get()));
-}
-
-#if !defined(_WIN32)
-TEST_F(InMemoryFileSystemTest, GetRealPath) {
-  SmallString<16> Path;
-  EXPECT_EQ(FS.getRealPath("b", Path), errc::operation_not_permitted);
-
-  auto GetRealPath = [this](StringRef P) {
-    SmallString<16> Output;
-    auto EC = FS.getRealPath(P, Output);
-    EXPECT_FALSE(EC);
-    return Output.str().str();
-  };
-
-  FS.setCurrentWorkingDirectory("a");
-  EXPECT_EQ(GetRealPath("b"), "a/b");
-  EXPECT_EQ(GetRealPath("../b"), "b");
-  EXPECT_EQ(GetRealPath("b/./c"), "a/b/c");
-
-  FS.setCurrentWorkingDirectory("/a");
-  EXPECT_EQ(GetRealPath("b"), "/a/b");
-  EXPECT_EQ(GetRealPath("../b"), "/b");
-  EXPECT_EQ(GetRealPath("b/./c"), "/a/b/c");
-}
-#endif // _WIN32
-
-TEST_F(InMemoryFileSystemTest, AddFileWithUser) {
-  FS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"), 0xFEEDFACE);
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_EQ(0xFEEDFACE, Stat->getUser());
-  Stat = FS.status("/a/b");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_EQ(0xFEEDFACE, Stat->getUser());
-  Stat = FS.status("/a/b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-  ASSERT_EQ(sys::fs::perms::all_all, Stat->getPermissions());
-  ASSERT_EQ(0xFEEDFACE, Stat->getUser());
-}
-
-TEST_F(InMemoryFileSystemTest, AddFileWithGroup) {
-  FS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"), None, 0xDABBAD00);
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_EQ(0xDABBAD00, Stat->getGroup());
-  Stat = FS.status("/a/b");
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_EQ(0xDABBAD00, Stat->getGroup());
-  Stat = FS.status("/a/b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-  ASSERT_EQ(sys::fs::perms::all_all, Stat->getPermissions());
-  ASSERT_EQ(0xDABBAD00, Stat->getGroup());
-}
-
-TEST_F(InMemoryFileSystemTest, AddFileWithFileType) {
-  FS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"), None, None,
-             sys::fs::file_type::socket_file);
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  Stat = FS.status("/a/b");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  Stat = FS.status("/a/b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_EQ(sys::fs::file_type::socket_file, Stat->getType());
-  ASSERT_EQ(sys::fs::perms::all_all, Stat->getPermissions());
-}
-
-TEST_F(InMemoryFileSystemTest, AddFileWithPerms) {
-  FS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"), None, None,
-             None, sys::fs::perms::owner_read | sys::fs::perms::owner_write);
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_EQ(sys::fs::perms::owner_read | sys::fs::perms::owner_write |
-            sys::fs::perms::owner_exe, Stat->getPermissions());
-  Stat = FS.status("/a/b");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  ASSERT_EQ(sys::fs::perms::owner_read | sys::fs::perms::owner_write |
-            sys::fs::perms::owner_exe, Stat->getPermissions());
-  Stat = FS.status("/a/b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-  ASSERT_EQ(sys::fs::perms::owner_read | sys::fs::perms::owner_write,
-            Stat->getPermissions());
-}
-
-TEST_F(InMemoryFileSystemTest, AddDirectoryThenAddChild) {
-  FS.addFile("/a", 0, MemoryBuffer::getMemBuffer(""), /*User=*/None,
-             /*Group=*/None, sys::fs::file_type::directory_file);
-  FS.addFile("/a/b", 0, MemoryBuffer::getMemBuffer("abc"), /*User=*/None,
-             /*Group=*/None, sys::fs::file_type::regular_file);
-  auto Stat = FS.status("/a");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isDirectory());
-  Stat = FS.status("/a/b");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n" << FS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-}
-
-// Test that the name returned by status() is in the same form as the path that
-// was requested (to match the behavior of RealFileSystem).
-TEST_F(InMemoryFileSystemTest, StatusName) {
-  NormalizedFS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"),
-                       /*User=*/None,
-                       /*Group=*/None, sys::fs::file_type::regular_file);
-  NormalizedFS.setCurrentWorkingDirectory("/a/b");
-
-  // Access using InMemoryFileSystem::status.
-  auto Stat = NormalizedFS.status("../b/c");
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n"
-                                << NormalizedFS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-  ASSERT_EQ("../b/c", Stat->getName());
-
-  // Access using InMemoryFileAdaptor::status.
-  auto File = NormalizedFS.openFileForRead("../b/c");
-  ASSERT_FALSE(File.getError()) << File.getError() << "\n"
-                                << NormalizedFS.toString();
-  Stat = (*File)->status();
-  ASSERT_FALSE(Stat.getError()) << Stat.getError() << "\n"
-                                << NormalizedFS.toString();
-  ASSERT_TRUE(Stat->isRegularFile());
-  ASSERT_EQ("../b/c", Stat->getName());
-
-  // Access using a directory iterator.
-  std::error_code EC;
-  clang::vfs::directory_iterator It = NormalizedFS.dir_begin("../b", EC);
-  // When on Windows, we end up with "../b\\c" as the name.  Convert to Posix
-  // path for the sake of the comparison.
-  ASSERT_EQ("../b/c", getPosixPath(It->path()));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkToFile) {
-  StringRef FromLink = "/path/to/FROM/link";
-  StringRef Target = "/path/to/TO/file";
-  FS.addFile(Target, 0, MemoryBuffer::getMemBuffer("content of target"));
-  EXPECT_TRUE(FS.addHardLink(FromLink, Target));
-  EXPECT_THAT(FromLink, IsHardLinkTo(&FS, Target));
-  EXPECT_TRUE(FS.status(FromLink)->getSize() == FS.status(Target)->getSize());
-  EXPECT_TRUE(FS.getBufferForFile(FromLink)->get()->getBuffer() ==
-              FS.getBufferForFile(Target)->get()->getBuffer());
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkInChainPattern) {
-  StringRef Link0 = "/path/to/0/link";
-  StringRef Link1 = "/path/to/1/link";
-  StringRef Link2 = "/path/to/2/link";
-  StringRef Target = "/path/to/target";
-  FS.addFile(Target, 0, MemoryBuffer::getMemBuffer("content of target file"));
-  EXPECT_TRUE(FS.addHardLink(Link2, Target));
-  EXPECT_TRUE(FS.addHardLink(Link1, Link2));
-  EXPECT_TRUE(FS.addHardLink(Link0, Link1));
-  EXPECT_THAT(Link0, IsHardLinkTo(&FS, Target));
-  EXPECT_THAT(Link1, IsHardLinkTo(&FS, Target));
-  EXPECT_THAT(Link2, IsHardLinkTo(&FS, Target));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkToAFileThatWasNotAddedBefore) {
-  EXPECT_FALSE(FS.addHardLink("/path/to/link", "/path/to/target"));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkFromAFileThatWasAddedBefore) {
-  StringRef Link = "/path/to/link";
-  StringRef Target = "/path/to/target";
-  FS.addFile(Target, 0, MemoryBuffer::getMemBuffer("content of target"));
-  FS.addFile(Link, 0, MemoryBuffer::getMemBuffer("content of link"));
-  EXPECT_FALSE(FS.addHardLink(Link, Target));
-}
-
-TEST_F(InMemoryFileSystemTest, AddSameHardLinkMoreThanOnce) {
-  StringRef Link = "/path/to/link";
-  StringRef Target = "/path/to/target";
-  FS.addFile(Target, 0, MemoryBuffer::getMemBuffer("content of target"));
-  EXPECT_TRUE(FS.addHardLink(Link, Target));
-  EXPECT_FALSE(FS.addHardLink(Link, Target));
-}
-
-TEST_F(InMemoryFileSystemTest, AddFileInPlaceOfAHardLinkWithSameContent) {
-  StringRef Link = "/path/to/link";
-  StringRef Target = "/path/to/target";
-  StringRef Content = "content of target";
-  EXPECT_TRUE(FS.addFile(Target, 0, MemoryBuffer::getMemBuffer(Content)));
-  EXPECT_TRUE(FS.addHardLink(Link, Target));
-  EXPECT_TRUE(FS.addFile(Link, 0, MemoryBuffer::getMemBuffer(Content)));
-}
-
-TEST_F(InMemoryFileSystemTest, AddFileInPlaceOfAHardLinkWithDifferentContent) {
-  StringRef Link = "/path/to/link";
-  StringRef Target = "/path/to/target";
-  StringRef Content = "content of target";
-  StringRef LinkContent = "different content of link";
-  EXPECT_TRUE(FS.addFile(Target, 0, MemoryBuffer::getMemBuffer(Content)));
-  EXPECT_TRUE(FS.addHardLink(Link, Target));
-  EXPECT_FALSE(FS.addFile(Link, 0, MemoryBuffer::getMemBuffer(LinkContent)));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkToADirectory) {
-  StringRef Dir = "path/to/dummy/dir";
-  StringRef Link = "/path/to/link";
-  StringRef File = "path/to/dummy/dir/target";
-  StringRef Content = "content of target";
-  EXPECT_TRUE(FS.addFile(File, 0, MemoryBuffer::getMemBuffer(Content)));
-  EXPECT_FALSE(FS.addHardLink(Link, Dir));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkFromADirectory) {
-  StringRef Dir = "path/to/dummy/dir";
-  StringRef Target = "path/to/dummy/dir/target";
-  StringRef Content = "content of target";
-  EXPECT_TRUE(FS.addFile(Target, 0, MemoryBuffer::getMemBuffer(Content)));
-  EXPECT_FALSE(FS.addHardLink(Dir, Target));
-}
-
-TEST_F(InMemoryFileSystemTest, AddHardLinkUnderAFile) {
-  StringRef CommonContent = "content string";
-  FS.addFile("/a/b", 0, MemoryBuffer::getMemBuffer(CommonContent));
-  FS.addFile("/c/d", 0, MemoryBuffer::getMemBuffer(CommonContent));
-  EXPECT_FALSE(FS.addHardLink("/c/d/e", "/a/b"));
-}
-
-TEST_F(InMemoryFileSystemTest, RecursiveIterationWithHardLink) {
-  std::error_code EC;
-  FS.addFile("/a/b", 0, MemoryBuffer::getMemBuffer("content string"));
-  EXPECT_TRUE(FS.addHardLink("/c/d", "/a/b"));
-  auto I = vfs::recursive_directory_iterator(FS, "/", EC);
-  ASSERT_FALSE(EC);
-  std::vector<std::string> Nodes;
-  for (auto E = vfs::recursive_directory_iterator(); !EC && I != E;
-       I.increment(EC)) {
-    Nodes.push_back(getPosixPath(I->path()));
-  }
-  EXPECT_THAT(Nodes, testing::UnorderedElementsAre("/a", "/a/b", "/c", "/c/d"));
-}
-
-// NOTE: in the tests below, we use '//root/' as our root directory, since it is
-// a legal *absolute* path on Windows as well as *nix.
-class VFSFromYAMLTest : public ::testing::Test {
-public:
-  int NumDiagnostics;
-
-  void SetUp() override { NumDiagnostics = 0; }
-
-  static void CountingDiagHandler(const SMDiagnostic &, void *Context) {
-    VFSFromYAMLTest *Test = static_cast<VFSFromYAMLTest *>(Context);
-    ++Test->NumDiagnostics;
-  }
-
-  IntrusiveRefCntPtr<vfs::FileSystem>
-  getFromYAMLRawString(StringRef Content,
-                       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS) {
-    std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBuffer(Content);
-    return getVFSFromYAML(std::move(Buffer), CountingDiagHandler, "", this,
-                          ExternalFS);
-  }
-
-  IntrusiveRefCntPtr<vfs::FileSystem> getFromYAMLString(
-      StringRef Content,
-      IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem()) {
-    std::string VersionPlusContent("{\n  'version':0,\n");
-    VersionPlusContent += Content.slice(Content.find('{') + 1, StringRef::npos);
-    return getFromYAMLRawString(VersionPlusContent, ExternalFS);
-  }
-
-  // This is intended as a "XFAIL" for windows hosts.
-  bool supportsSameDirMultipleYAMLEntries() {
-    Triple Host(Triple::normalize(sys::getProcessTriple()));
-    return !Host.isOSWindows();
-  }
-};
-
-TEST_F(VFSFromYAMLTest, BasicVFSFromYAML) {
-  IntrusiveRefCntPtr<vfs::FileSystem> FS;
-  FS = getFromYAMLString("");
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("[]");
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("'string'");
-  EXPECT_EQ(nullptr, FS.get());
-  EXPECT_EQ(3, NumDiagnostics);
-}
-
-TEST_F(VFSFromYAMLTest, MappedFiles) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/foo/bar/a");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS =
-      getFromYAMLString("{ 'roots': [\n"
-                        "{\n"
-                        "  'type': 'directory',\n"
-                        "  'name': '//root/',\n"
-                        "  'contents': [ {\n"
-                        "                  'type': 'file',\n"
-                        "                  'name': 'file1',\n"
-                        "                  'external-contents': '//root/foo/bar/a'\n"
-                        "                },\n"
-                        "                {\n"
-                        "                  'type': 'file',\n"
-                        "                  'name': 'file2',\n"
-                        "                  'external-contents': '//root/foo/b'\n"
-                        "                }\n"
-                        "              ]\n"
-                        "}\n"
-                        "]\n"
-                        "}",
-                        Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  // file
-  ErrorOr<vfs::Status> S = O->status("//root/file1");
-  ASSERT_FALSE(S.getError());
-  EXPECT_EQ("//root/foo/bar/a", S->getName());
-  EXPECT_TRUE(S->IsVFSMapped);
-
-  ErrorOr<vfs::Status> SLower = O->status("//root/foo/bar/a");
-  EXPECT_EQ("//root/foo/bar/a", SLower->getName());
-  EXPECT_TRUE(S->equivalent(*SLower));
-  EXPECT_FALSE(SLower->IsVFSMapped);
-
-  // file after opening
-  auto OpenedF = O->openFileForRead("//root/file1");
-  ASSERT_FALSE(OpenedF.getError());
-  auto OpenedS = (*OpenedF)->status();
-  ASSERT_FALSE(OpenedS.getError());
-  EXPECT_EQ("//root/foo/bar/a", OpenedS->getName());
-  EXPECT_TRUE(OpenedS->IsVFSMapped);
-
-  // directory
-  S = O->status("//root/");
-  ASSERT_FALSE(S.getError());
-  EXPECT_TRUE(S->isDirectory());
-  EXPECT_TRUE(S->equivalent(*O->status("//root/"))); // non-volatile UniqueID
-
-  // broken mapping
-  EXPECT_EQ(O->status("//root/file2").getError(),
-            llvm::errc::no_such_file_or_directory);
-  EXPECT_EQ(0, NumDiagnostics);
-}
-
-TEST_F(VFSFromYAMLTest, CaseInsensitive) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/foo/bar/a");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS =
-      getFromYAMLString("{ 'case-sensitive': 'false',\n"
-                        "  'roots': [\n"
-                        "{\n"
-                        "  'type': 'directory',\n"
-                        "  'name': '//root/',\n"
-                        "  'contents': [ {\n"
-                        "                  'type': 'file',\n"
-                        "                  'name': 'XX',\n"
-                        "                  'external-contents': '//root/foo/bar/a'\n"
-                        "                }\n"
-                        "              ]\n"
-                        "}]}",
-                        Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  ErrorOr<vfs::Status> S = O->status("//root/XX");
-  ASSERT_FALSE(S.getError());
-
-  ErrorOr<vfs::Status> SS = O->status("//root/xx");
-  ASSERT_FALSE(SS.getError());
-  EXPECT_TRUE(S->equivalent(*SS));
-  SS = O->status("//root/xX");
-  EXPECT_TRUE(S->equivalent(*SS));
-  SS = O->status("//root/Xx");
-  EXPECT_TRUE(S->equivalent(*SS));
-  EXPECT_EQ(0, NumDiagnostics);
-}
-
-TEST_F(VFSFromYAMLTest, CaseSensitive) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/foo/bar/a");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS =
-      getFromYAMLString("{ 'case-sensitive': 'true',\n"
-                        "  'roots': [\n"
-                        "{\n"
-                        "  'type': 'directory',\n"
-                        "  'name': '//root/',\n"
-                        "  'contents': [ {\n"
-                        "                  'type': 'file',\n"
-                        "                  'name': 'XX',\n"
-                        "                  'external-contents': '//root/foo/bar/a'\n"
-                        "                }\n"
-                        "              ]\n"
-                        "}]}",
-                        Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  ErrorOr<vfs::Status> SS = O->status("//root/xx");
-  EXPECT_EQ(SS.getError(), llvm::errc::no_such_file_or_directory);
-  SS = O->status("//root/xX");
-  EXPECT_EQ(SS.getError(), llvm::errc::no_such_file_or_directory);
-  SS = O->status("//root/Xx");
-  EXPECT_EQ(SS.getError(), llvm::errc::no_such_file_or_directory);
-  EXPECT_EQ(0, NumDiagnostics);
-}
-
-TEST_F(VFSFromYAMLTest, IllegalVFSFile) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-
-  // invalid YAML at top-level
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString("{]", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  // invalid YAML in roots
-  FS = getFromYAMLString("{ 'roots':[}", Lower);
-  // invalid YAML in directory
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'name': 'foo', 'type': 'directory', 'contents': [}",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // invalid configuration
-  FS = getFromYAMLString("{ 'knobular': 'true', 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("{ 'case-sensitive': 'maybe', 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // invalid roots
-  FS = getFromYAMLString("{ 'roots':'' }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("{ 'roots':{} }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // invalid entries
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'other', 'name': 'me', 'contents': '' }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("{ 'roots':[ { 'type': 'file', 'name': [], "
-                         "'external-contents': 'other' }",
-                         Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'file', 'name': 'me', 'external-contents': [] }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'file', 'name': 'me', 'external-contents': {} }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'directory', 'name': 'me', 'contents': {} }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'directory', 'name': 'me', 'contents': '' }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'thingy': 'directory', 'name': 'me', 'contents': [] }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // missing mandatory fields
-  FS = getFromYAMLString("{ 'roots':[ { 'type': 'file', 'name': 'me' }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'roots':[ { 'type': 'file', 'external-contents': 'other' }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString("{ 'roots':[ { 'name': 'me', 'contents': [] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // duplicate keys
-  FS = getFromYAMLString("{ 'roots':[], 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLString(
-      "{ 'case-sensitive':'true', 'case-sensitive':'true', 'roots':[] }",
-      Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS =
-      getFromYAMLString("{ 'roots':[{'name':'me', 'name':'you', 'type':'file', "
-                        "'external-contents':'blah' } ] }",
-                        Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // missing version
-  FS = getFromYAMLRawString("{ 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // bad version number
-  FS = getFromYAMLRawString("{ 'version':'foo', 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLRawString("{ 'version':-1, 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  FS = getFromYAMLRawString("{ 'version':100000, 'roots':[] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-  EXPECT_EQ(24, NumDiagnostics);
-}
-
-TEST_F(VFSFromYAMLTest, UseExternalName) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/external/file");
-
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'file', 'name': '//root/A',\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  },\n"
-      "  { 'type': 'file', 'name': '//root/B',\n"
-      "    'use-external-name': true,\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  },\n"
-      "  { 'type': 'file', 'name': '//root/C',\n"
-      "    'use-external-name': false,\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  }\n"
-      "] }", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-
-  // default true
-  EXPECT_EQ("//root/external/file", FS->status("//root/A")->getName());
-  // explicit
-  EXPECT_EQ("//root/external/file", FS->status("//root/B")->getName());
-  EXPECT_EQ("//root/C", FS->status("//root/C")->getName());
-
-  // global configuration
-  FS = getFromYAMLString(
-      "{ 'use-external-names': false,\n"
-      "  'roots': [\n"
-      "  { 'type': 'file', 'name': '//root/A',\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  },\n"
-      "  { 'type': 'file', 'name': '//root/B',\n"
-      "    'use-external-name': true,\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  },\n"
-      "  { 'type': 'file', 'name': '//root/C',\n"
-      "    'use-external-name': false,\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  }\n"
-      "] }", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-
-  // default
-  EXPECT_EQ("//root/A", FS->status("//root/A")->getName());
-  // explicit
-  EXPECT_EQ("//root/external/file", FS->status("//root/B")->getName());
-  EXPECT_EQ("//root/C", FS->status("//root/C")->getName());
-}
-
-TEST_F(VFSFromYAMLTest, MultiComponentPath) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/other");
-
-  // file in roots
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'file', 'name': '//root/path/to/file',\n"
-      "    'external-contents': '//root/other' }]\n"
-      "}", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-  EXPECT_FALSE(FS->status("//root/path/to/file").getError());
-  EXPECT_FALSE(FS->status("//root/path/to").getError());
-  EXPECT_FALSE(FS->status("//root/path").getError());
-  EXPECT_FALSE(FS->status("//root/").getError());
-
-  // at the start
-  FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'directory', 'name': '//root/path/to',\n"
-      "    'contents': [ { 'type': 'file', 'name': 'file',\n"
-      "                    'external-contents': '//root/other' }]}]\n"
-      "}", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-  EXPECT_FALSE(FS->status("//root/path/to/file").getError());
-  EXPECT_FALSE(FS->status("//root/path/to").getError());
-  EXPECT_FALSE(FS->status("//root/path").getError());
-  EXPECT_FALSE(FS->status("//root/").getError());
-
-  // at the end
-  FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'directory', 'name': '//root/',\n"
-      "    'contents': [ { 'type': 'file', 'name': 'path/to/file',\n"
-      "                    'external-contents': '//root/other' }]}]\n"
-      "}", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-  EXPECT_FALSE(FS->status("//root/path/to/file").getError());
-  EXPECT_FALSE(FS->status("//root/path/to").getError());
-  EXPECT_FALSE(FS->status("//root/path").getError());
-  EXPECT_FALSE(FS->status("//root/").getError());
-}
-
-TEST_F(VFSFromYAMLTest, TrailingSlashes) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addRegularFile("//root/other");
-
-  // file in roots
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'directory', 'name': '//root/path/to////',\n"
-      "    'contents': [ { 'type': 'file', 'name': 'file',\n"
-      "                    'external-contents': '//root/other' }]}]\n"
-      "}", Lower);
-  ASSERT_TRUE(nullptr != FS.get());
-  EXPECT_FALSE(FS->status("//root/path/to/file").getError());
-  EXPECT_FALSE(FS->status("//root/path/to").getError());
-  EXPECT_FALSE(FS->status("//root/path").getError());
-  EXPECT_FALSE(FS->status("//root/").getError());
-}
-
-TEST_F(VFSFromYAMLTest, DirectoryIteration) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addDirectory("//root/");
-  Lower->addDirectory("//root/foo");
-  Lower->addDirectory("//root/foo/bar");
-  Lower->addRegularFile("//root/foo/bar/a");
-  Lower->addRegularFile("//root/foo/bar/b");
-  Lower->addRegularFile("//root/file3");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS =
-  getFromYAMLString("{ 'use-external-names': false,\n"
-                    "  'roots': [\n"
-                    "{\n"
-                    "  'type': 'directory',\n"
-                    "  'name': '//root/',\n"
-                    "  'contents': [ {\n"
-                    "                  'type': 'file',\n"
-                    "                  'name': 'file1',\n"
-                    "                  'external-contents': '//root/foo/bar/a'\n"
-                    "                },\n"
-                    "                {\n"
-                    "                  'type': 'file',\n"
-                    "                  'name': 'file2',\n"
-                    "                  'external-contents': '//root/foo/bar/b'\n"
-                    "                }\n"
-                    "              ]\n"
-                    "}\n"
-                    "]\n"
-                    "}",
-                    Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  std::error_code EC;
-  checkContents(O->dir_begin("//root/", EC),
-                {"//root/file1", "//root/file2", "//root/file3", "//root/foo"});
-
-  checkContents(O->dir_begin("//root/foo/bar", EC),
-                {"//root/foo/bar/a", "//root/foo/bar/b"});
-}
-
-TEST_F(VFSFromYAMLTest, DirectoryIterationSameDirMultipleEntries) {
-  // https://llvm.org/bugs/show_bug.cgi?id=27725
-  if (!supportsSameDirMultipleYAMLEntries())
-    return;
-
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addDirectory("//root/zab");
-  Lower->addDirectory("//root/baz");
-  Lower->addRegularFile("//root/zab/a");
-  Lower->addRegularFile("//root/zab/b");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'use-external-names': false,\n"
-      "  'roots': [\n"
-      "{\n"
-      "  'type': 'directory',\n"
-      "  'name': '//root/baz/',\n"
-      "  'contents': [ {\n"
-      "                  'type': 'file',\n"
-      "                  'name': 'x',\n"
-      "                  'external-contents': '//root/zab/a'\n"
-      "                }\n"
-      "              ]\n"
-      "},\n"
-      "{\n"
-      "  'type': 'directory',\n"
-      "  'name': '//root/baz/',\n"
-      "  'contents': [ {\n"
-      "                  'type': 'file',\n"
-      "                  'name': 'y',\n"
-      "                  'external-contents': '//root/zab/b'\n"
-      "                }\n"
-      "              ]\n"
-      "}\n"
-      "]\n"
-      "}",
-      Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  std::error_code EC;
-
-  checkContents(O->dir_begin("//root/baz/", EC),
-                {"//root/baz/x", "//root/baz/y"});
-}
-
-TEST_F(VFSFromYAMLTest, RecursiveDirectoryIterationLevel) {
-
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  Lower->addDirectory("//root/a");
-  Lower->addDirectory("//root/a/b");
-  Lower->addDirectory("//root/a/b/c");
-  Lower->addRegularFile("//root/a/b/c/file");
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'use-external-names': false,\n"
-      "  'roots': [\n"
-      "{\n"
-      "  'type': 'directory',\n"
-      "  'name': '//root/a/b/c/',\n"
-      "  'contents': [ {\n"
-      "                  'type': 'file',\n"
-      "                  'name': 'file',\n"
-      "                  'external-contents': '//root/a/b/c/file'\n"
-      "                }\n"
-      "              ]\n"
-      "},\n"
-      "]\n"
-      "}",
-      Lower);
-  ASSERT_TRUE(FS.get() != nullptr);
-
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
-      new vfs::OverlayFileSystem(Lower));
-  O->pushOverlay(FS);
-
-  std::error_code EC;
-
-  // Test recursive_directory_iterator level()
-  vfs::recursive_directory_iterator I = vfs::recursive_directory_iterator(
-                                        *O, "//root", EC), E;
-  ASSERT_FALSE(EC);
-  for (int l = 0; I != E; I.increment(EC), ++l) {
-    ASSERT_FALSE(EC);
-    EXPECT_EQ(I.level(), l);
-  }
-  EXPECT_EQ(I, E);
-}
-
-TEST_F(VFSFromYAMLTest, RelativePaths) {
-  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
-  // Filename at root level without a parent directory.
-  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'file', 'name': 'file-not-in-directory.h',\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  }\n"
-      "] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // Relative file path.
-  FS = getFromYAMLString(
-      "{ 'roots': [\n"
-      "  { 'type': 'file', 'name': 'relative/file/path.h',\n"
-      "    'external-contents': '//root/external/file'\n"
-      "  }\n"
-      "] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  // Relative directory path.
-  FS = getFromYAMLString(
-       "{ 'roots': [\n"
-       "  { 'type': 'directory', 'name': 'relative/directory/path.h',\n"
-       "    'contents': []\n"
-       "  }\n"
-       "] }", Lower);
-  EXPECT_EQ(nullptr, FS.get());
-
-  EXPECT_EQ(3, NumDiagnostics);
-}

unittests/Driver/DistroTest.cpp

@@ -12,7 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Driver/Distro.h"
-#include "clang/Basic/VirtualFileSystem.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 using namespace clang;
@@ -25,7 +25,7 @@ namespace {
 // accidentally result in incorrect distribution guess.
 
 TEST(DistroTest, DetectUbuntu) {
-  vfs::InMemoryFileSystem UbuntuTrustyFileSystem;
+  llvm::vfs::InMemoryFileSystem UbuntuTrustyFileSystem;
   // Ubuntu uses Debian Sid version.
   UbuntuTrustyFileSystem.addFile("/etc/debian_version", 0,
       llvm::MemoryBuffer::getMemBuffer("jessie/sid\n"));
@@ -52,7 +52,7 @@ TEST(DistroTest, DetectUbuntu) {
   ASSERT_FALSE(UbuntuTrusty.IsOpenSUSE());
   ASSERT_FALSE(UbuntuTrusty.IsDebian());
 
-  vfs::InMemoryFileSystem UbuntuYakketyFileSystem;
+  llvm::vfs::InMemoryFileSystem UbuntuYakketyFileSystem;
   UbuntuYakketyFileSystem.addFile("/etc/debian_version", 0,
       llvm::MemoryBuffer::getMemBuffer("stretch/sid\n"));
   UbuntuYakketyFileSystem.addFile("/etc/lsb-release", 0,
@@ -83,7 +83,7 @@ TEST(DistroTest, DetectUbuntu) {
 }
 
 TEST(DistroTest, DetectRedhat) {
-  vfs::InMemoryFileSystem Fedora25FileSystem;
+  llvm::vfs::InMemoryFileSystem Fedora25FileSystem;
   Fedora25FileSystem.addFile("/etc/system-release-cpe", 0,
       llvm::MemoryBuffer::getMemBuffer("cpe:/o:fedoraproject:fedora:25\n"));
   // Both files are symlinks to fedora-release.
@@ -115,7 +115,7 @@ TEST(DistroTest, DetectRedhat) {
   ASSERT_FALSE(Fedora25.IsOpenSUSE());
   ASSERT_FALSE(Fedora25.IsDebian());
 
-  vfs::InMemoryFileSystem CentOS7FileSystem;
+  llvm::vfs::InMemoryFileSystem CentOS7FileSystem;
   CentOS7FileSystem.addFile("/etc/system-release-cpe", 0,
       llvm::MemoryBuffer::getMemBuffer("cpe:/o:centos:centos:7\n"));
   // Both files are symlinks to centos-release.
@@ -153,7 +153,7 @@ TEST(DistroTest, DetectRedhat) {
 }
 
 TEST(DistroTest, DetectOpenSUSE) {
-  vfs::InMemoryFileSystem OpenSUSELeap421FileSystem;
+  llvm::vfs::InMemoryFileSystem OpenSUSELeap421FileSystem;
   OpenSUSELeap421FileSystem.addFile("/etc/SuSE-release", 0,
       llvm::MemoryBuffer::getMemBuffer("openSUSE 42.1 (x86_64)\n"
                                        "VERSION = 42.1\n"
@@ -178,7 +178,7 @@ TEST(DistroTest, DetectOpenSUSE) {
   ASSERT_TRUE(OpenSUSELeap421.IsOpenSUSE());
   ASSERT_FALSE(OpenSUSELeap421.IsDebian());
 
-  vfs::InMemoryFileSystem OpenSUSE132FileSystem;
+  llvm::vfs::InMemoryFileSystem OpenSUSE132FileSystem;
   OpenSUSE132FileSystem.addFile("/etc/SuSE-release", 0,
       llvm::MemoryBuffer::getMemBuffer("openSUSE 13.2 (x86_64)\n"
                                        "VERSION = 13.2\n"
@@ -203,7 +203,7 @@ TEST(DistroTest, DetectOpenSUSE) {
   ASSERT_TRUE(OpenSUSE132.IsOpenSUSE());
   ASSERT_FALSE(OpenSUSE132.IsDebian());
 
-  vfs::InMemoryFileSystem SLES10FileSystem;
+  llvm::vfs::InMemoryFileSystem SLES10FileSystem;
   SLES10FileSystem.addFile("/etc/SuSE-release", 0,
       llvm::MemoryBuffer::getMemBuffer("SUSE Linux Enterprise Server 10 (x86_64)\n"
                                        "VERSION = 10\n"
@@ -221,7 +221,7 @@ TEST(DistroTest, DetectOpenSUSE) {
 }
 
 TEST(DistroTest, DetectDebian) {
-  vfs::InMemoryFileSystem DebianJessieFileSystem;
+  llvm::vfs::InMemoryFileSystem DebianJessieFileSystem;
   DebianJessieFileSystem.addFile("/etc/debian_version", 0,
                                  llvm::MemoryBuffer::getMemBuffer("8.6\n"));
   DebianJessieFileSystem.addFile("/etc/os-release", 0,
@@ -241,7 +241,7 @@ TEST(DistroTest, DetectDebian) {
   ASSERT_FALSE(DebianJessie.IsOpenSUSE());
   ASSERT_TRUE(DebianJessie.IsDebian());
 
-  vfs::InMemoryFileSystem DebianStretchSidFileSystem;
+  llvm::vfs::InMemoryFileSystem DebianStretchSidFileSystem;
   DebianStretchSidFileSystem.addFile("/etc/debian_version", 0,
                                  llvm::MemoryBuffer::getMemBuffer("stretch/sid\n"));
   DebianStretchSidFileSystem.addFile("/etc/os-release", 0,
@@ -261,7 +261,7 @@ TEST(DistroTest, DetectDebian) {
 }
 
 TEST(DistroTest, DetectExherbo) {
-  vfs::InMemoryFileSystem ExherboFileSystem;
+  llvm::vfs::InMemoryFileSystem ExherboFileSystem;
   ExherboFileSystem.addFile("/etc/exherbo-release", 0, // (ASCII art)
                                  llvm::MemoryBuffer::getMemBuffer(""));
   ExherboFileSystem.addFile("/etc/os-release", 0,
@@ -282,7 +282,7 @@ TEST(DistroTest, DetectExherbo) {
 }
 
 TEST(DistroTest, DetectArchLinux) {
-  vfs::InMemoryFileSystem ArchLinuxFileSystem;
+  llvm::vfs::InMemoryFileSystem ArchLinuxFileSystem;
   ArchLinuxFileSystem.addFile("/etc/arch-release", 0, // (empty)
                                  llvm::MemoryBuffer::getMemBuffer(""));
   ArchLinuxFileSystem.addFile("/etc/os-release", 0,

unittests/Driver/ToolChainTest.cpp

@@ -15,11 +15,11 @@
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 using namespace clang;
@@ -33,8 +33,8 @@ TEST(ToolChainTest, VFSGCCInstallation) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
   struct TestDiagnosticConsumer : public DiagnosticConsumer {};
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, new TestDiagnosticConsumer);
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   Driver TheDriver("/bin/clang", "arm-linux-gnueabihf", Diags,
                    InMemoryFileSystem);
 
@@ -87,8 +87,8 @@ TEST(ToolChainTest, VFSGCCInstallationRelativeDir) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
   struct TestDiagnosticConsumer : public DiagnosticConsumer {};
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, new TestDiagnosticConsumer);
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   Driver TheDriver("/home/test/bin/clang", "arm-linux-gnueabi", Diags,
                    InMemoryFileSystem);
 
@@ -127,8 +127,8 @@ TEST(ToolChainTest, DefaultDriverMode) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
   struct TestDiagnosticConsumer : public DiagnosticConsumer {};
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, new TestDiagnosticConsumer);
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
 
   Driver CCDriver("/home/test/bin/clang", "arm-linux-gnueabi", Diags,
                   InMemoryFileSystem);

unittests/Format/FormatTest.cpp

@@ -12375,14 +12375,14 @@ TEST_F(FormatTest, NoSpaceAfterSuper) {
 }
 
 TEST(FormatStyle, GetStyleWithEmptyFileName) {
-  vfs::InMemoryFileSystem FS;
+  llvm::vfs::InMemoryFileSystem FS;
   auto Style1 = getStyle("file", "", "Google", "", &FS);
   ASSERT_TRUE((bool)Style1);
   ASSERT_EQ(*Style1, getGoogleStyle());
 }
 
 TEST(FormatStyle, GetStyleOfFile) {
-  vfs::InMemoryFileSystem FS;
+  llvm::vfs::InMemoryFileSystem FS;
   // Test 1: format file in the same directory.
   ASSERT_TRUE(
       FS.addFile("/a/.clang-format", 0,

unittests/Index/IndexTests.cpp

@@ -9,7 +9,6 @@
 
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/Decl.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Index/IndexDataConsumer.h"
@@ -18,6 +17,7 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include <memory>

unittests/Lex/HeaderSearchTest.cpp

@@ -27,7 +27,7 @@ namespace {
 class HeaderSearchTest : public ::testing::Test {
 protected:
   HeaderSearchTest()
-      : VFS(new vfs::InMemoryFileSystem), FileMgr(FileMgrOpts, VFS),
+      : VFS(new llvm::vfs::InMemoryFileSystem), FileMgr(FileMgrOpts, VFS),
         DiagID(new DiagnosticIDs()),
         Diags(DiagID, new DiagnosticOptions, new IgnoringDiagConsumer()),
         SourceMgr(Diags, FileMgr), TargetOpts(new TargetOptions),
@@ -46,7 +46,7 @@ protected:
     Search.AddSearchPath(DL, /*isAngled=*/false);
   }
 
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> VFS;
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS;
   FileSystemOptions FileMgrOpts;
   FileManager FileMgr;
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID;

unittests/Lex/PPCallbacksTest.cpp

@@ -95,7 +95,7 @@ public:
 class PPCallbacksTest : public ::testing::Test {
 protected:
   PPCallbacksTest()
-      : InMemoryFileSystem(new vfs::InMemoryFileSystem),
+      : InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
         FileMgr(FileSystemOptions(), InMemoryFileSystem),
         DiagID(new DiagnosticIDs()), DiagOpts(new DiagnosticOptions()),
         Diags(DiagID, DiagOpts.get(), new IgnoringDiagConsumer()),
@@ -104,7 +104,7 @@ protected:
     Target = TargetInfo::CreateTargetInfo(Diags, TargetOpts);
   }
 
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem;
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem;
   FileManager FileMgr;
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID;
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
@@ -116,17 +116,17 @@ protected:
 
   // Register a header path as a known file and add its location
   // to search path.
-  void AddFakeHeader(HeaderSearch& HeaderInfo, const char* HeaderPath, 
-    bool IsSystemHeader) {
-      // Tell FileMgr about header.
-      InMemoryFileSystem->addFile(HeaderPath, 0,
-                                  llvm::MemoryBuffer::getMemBuffer("\n"));
-
-      // Add header's parent path to search path.
-      StringRef SearchPath = llvm::sys::path::parent_path(HeaderPath);
-      const DirectoryEntry *DE = FileMgr.getDirectory(SearchPath);
-      DirectoryLookup DL(DE, SrcMgr::C_User, false);
-      HeaderInfo.AddSearchPath(DL, IsSystemHeader);
+  void AddFakeHeader(HeaderSearch &HeaderInfo, const char *HeaderPath,
+                     bool IsSystemHeader) {
+    // Tell FileMgr about header.
+    InMemoryFileSystem->addFile(HeaderPath, 0,
+                                llvm::MemoryBuffer::getMemBuffer("\n"));
+
+    // Add header's parent path to search path.
+    StringRef SearchPath = llvm::sys::path::parent_path(HeaderPath);
+    const DirectoryEntry *DE = FileMgr.getDirectory(SearchPath);
+    DirectoryLookup DL(DE, SrcMgr::C_User, false);
+    HeaderInfo.AddSearchPath(DL, IsSystemHeader);
   }
 
   // Get the raw source string of the range.
@@ -139,8 +139,9 @@ protected:
 
   // Run lexer over SourceText and collect FilenameRange from
   // the InclusionDirective callback.
-  CharSourceRange InclusionDirectiveFilenameRange(const char* SourceText, 
-      const char* HeaderPath, bool SystemHeader) {
+  CharSourceRange InclusionDirectiveFilenameRange(const char *SourceText,
+                                                  const char *HeaderPath,
+                                                  bool SystemHeader) {
     std::unique_ptr<llvm::MemoryBuffer> Buf =
         llvm::MemoryBuffer::getMemBuffer(SourceText);
     SourceMgr.setMainFileID(SourceMgr.createFileID(std::move(Buf)));
@@ -198,8 +199,8 @@ protected:
     return Callbacks;
   }
 
-  PragmaOpenCLExtensionCallbacks::CallbackParameters 
-  PragmaOpenCLExtensionCall(const char* SourceText) {
+  PragmaOpenCLExtensionCallbacks::CallbackParameters
+  PragmaOpenCLExtensionCall(const char *SourceText) {
     LangOptions OpenCLLangOpts;
     OpenCLLangOpts.OpenCL = 1;
 
@@ -221,9 +222,8 @@ protected:
     // parser actually sets correct pragma handlers for preprocessor
     // according to LangOptions, so we init Parser to register opencl
     // pragma handlers
-    ASTContext Context(OpenCLLangOpts, SourceMgr,
-                       PP.getIdentifierTable(), PP.getSelectorTable(), 
-                       PP.getBuiltinInfo());
+    ASTContext Context(OpenCLLangOpts, SourceMgr, PP.getIdentifierTable(),
+                       PP.getSelectorTable(), PP.getBuiltinInfo());
     Context.InitBuiltinTypes(*Target);
 
     ASTConsumer Consumer;
@@ -245,7 +245,7 @@ protected:
       Callbacks->Name,
       Callbacks->State
     };
-    return RetVal;    
+    return RetVal;
   }
 };
 

unittests/Rename/ClangRenameTest.h

@@ -14,7 +14,6 @@
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/FileSystemOptions.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Format/Format.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/PCHContainerOperations.h"
@@ -26,6 +25,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "gtest/gtest.h"
 #include <memory>
 #include <string>

unittests/Tooling/RefactoringTest.cpp

@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/Tooling/Refactoring.h"
 #include "ReplacementTest.h"
 #include "RewriterTestContext.h"
 #include "clang/AST/ASTConsumer.h"
@@ -19,16 +20,15 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Format/Format.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Rewrite/Core/Rewriter.h"
-#include "clang/Tooling/Refactoring.h"
 #include "clang/Tooling/Refactoring/AtomicChange.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "gtest/gtest.h"
 
 namespace clang {
@@ -1032,8 +1032,8 @@ TEST_F(MergeReplacementsTest, OverlappingRanges) {
 
 TEST(DeduplicateByFileTest, PathsWithDots) {
   std::map<std::string, Replacements> FileToReplaces;
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> VFS(
-      new vfs::InMemoryFileSystem());
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
   FileManager FileMgr(FileSystemOptions(), VFS);
 #if !defined(_WIN32)
   StringRef Path1 = "a/b/.././c.h";
@@ -1053,8 +1053,8 @@ TEST(DeduplicateByFileTest, PathsWithDots) {
 
 TEST(DeduplicateByFileTest, PathWithDotSlash) {
   std::map<std::string, Replacements> FileToReplaces;
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> VFS(
-      new vfs::InMemoryFileSystem());
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
   FileManager FileMgr(FileSystemOptions(), VFS);
 #if !defined(_WIN32)
   StringRef Path1 = "./a/b/c.h";
@@ -1074,8 +1074,8 @@ TEST(DeduplicateByFileTest, PathWithDotSlash) {
 
 TEST(DeduplicateByFileTest, NonExistingFilePath) {
   std::map<std::string, Replacements> FileToReplaces;
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> VFS(
-      new vfs::InMemoryFileSystem());
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> VFS(
+      new llvm::vfs::InMemoryFileSystem());
   FileManager FileMgr(FileSystemOptions(), VFS);
 #if !defined(_WIN32)
   StringRef Path1 = "./a/b/c.h";

unittests/Tooling/RewriterTestContext.h

@@ -39,15 +39,15 @@ class RewriterTestContext {
          Diagnostics(IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),
                      &*DiagOpts),
          DiagnosticPrinter(llvm::outs(), &*DiagOpts),
-         InMemoryFileSystem(new vfs::InMemoryFileSystem),
+         InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
          OverlayFileSystem(
-             new vfs::OverlayFileSystem(vfs::getRealFileSystem())),
+             new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem())),
          Files(FileSystemOptions(), OverlayFileSystem),
          Sources(Diagnostics, Files), Rewrite(Sources, Options) {
-    Diagnostics.setClient(&DiagnosticPrinter, false);
-    // FIXME: To make these tests truly in-memory, we need to overlay the
-    // builtin headers.
-    OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+     Diagnostics.setClient(&DiagnosticPrinter, false);
+     // FIXME: To make these tests truly in-memory, we need to overlay the
+     // builtin headers.
+     OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   }
 
   ~RewriterTestContext() {}
@@ -114,8 +114,8 @@ class RewriterTestContext {
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
   DiagnosticsEngine Diagnostics;
   TextDiagnosticPrinter DiagnosticPrinter;
-  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem;
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem;
+  IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem;
+  IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem;
   FileManager Files;
   SourceManager Sources;
   LangOptions Options;

unittests/Tooling/ToolingTest.cpp

@@ -149,10 +149,10 @@ TEST(newFrontendActionFactory, CreatesFrontendActionFactoryFromFactoryType) {
 }
 
 TEST(ToolInvocation, TestMapVirtualFile) {
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
-      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   llvm::IntrusiveRefCntPtr<FileManager> Files(
       new FileManager(FileSystemOptions(), OverlayFileSystem));
@@ -175,10 +175,10 @@ TEST(ToolInvocation, TestVirtualModulesCompilation) {
   // mapped module.map is found on the include path. In the future, expand this
   // test to run a full modules enabled compilation, so we make sure we can
   // rerun modules compilations with a virtual file system.
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
-      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   llvm::IntrusiveRefCntPtr<FileManager> Files(
       new FileManager(FileSystemOptions(), OverlayFileSystem));
@@ -403,10 +403,10 @@ TEST(ClangToolTest, ArgumentAdjusters) {
 
 TEST(ClangToolTest, BaseVirtualFileSystemUsage) {
   FixedCompilationDatabase Compilations("/", std::vector<std::string>());
-  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
-      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
-  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
-      new vfs::InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
+      new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new llvm::vfs::InMemoryFileSystem);
   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
 
   InMemoryFileSystem->addFile(