[Basic] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 328735

4 files changed, 193 insertions, 103 deletions

diff --git a/clang/lib/Basic/FileSystemStatCache.cpp b/clang/lib/Basic/FileSystemStatCache.cpp
index 799df1d3c3a..ebee32670e0 100644
--- a/clang/lib/Basic/FileSystemStatCache.cpp
+++ b/clang/lib/Basic/FileSystemStatCache.cpp
@@ -1,4 +1,4 @@
-//===--- FileSystemStatCache.cpp - Caching for 'stat' calls ---------------===//
+//===- FileSystemStatCache.cpp - Caching for 'stat' calls -----------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -13,11 +13,14 @@
 
 #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 <utility>
 
 using namespace clang;
 
-void FileSystemStatCache::anchor() { }
+void FileSystemStatCache::anchor() {}
 
 static void copyStatusToFileData(const vfs::Status &Status,
                                  FileData &Data) {
diff --git a/clang/lib/Basic/ObjCRuntime.cpp b/clang/lib/Basic/ObjCRuntime.cpp
index 133c66945dd..15f38d1156a 100644
--- a/clang/lib/Basic/ObjCRuntime.cpp
+++ b/clang/lib/Basic/ObjCRuntime.cpp
@@ -1,4 +1,4 @@
-//===- ObjCRuntime.cpp - Objective-C Runtime Handling -----------*- C++ -*-===//
+//===- ObjCRuntime.cpp - Objective-C Runtime Handling ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -11,8 +11,13 @@
 // target Objective-C runtime.
 //
 //===----------------------------------------------------------------------===//
+
 #include "clang/Basic/ObjCRuntime.h"
+#include "clang/Basic/VersionTuple.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/raw_ostream.h"
+#include <cstddef>
+#include <string>
 
 using namespace clang;
 
diff --git a/clang/lib/Basic/Sanitizers.cpp b/clang/lib/Basic/Sanitizers.cpp
index 91b6b2dc74e..8faf17b8f22 100644
--- a/clang/lib/Basic/Sanitizers.cpp
+++ b/clang/lib/Basic/Sanitizers.cpp
@@ -1,4 +1,4 @@
-//===--- Sanitizers.cpp - C Language Family Language Options ----*- C++ -*-===//
+//===- Sanitizers.cpp - C Language Family Language Options ----------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -10,9 +10,8 @@
 //  This file defines the classes from Sanitizers.h
 //
 //===----------------------------------------------------------------------===//
+
 #include "clang/Basic/Sanitizers.h"
-#include "clang/Basic/LLVM.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 
 using namespace clang;
diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index e95b32a22d7..a8545769593 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -1,4 +1,4 @@
-//===- VirtualFileSystem.cpp - Virtual File System Layer --------*- C++ -*-===//
+//===- VirtualFileSystem.cpp - Virtual File System Layer ------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -6,30 +6,57 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
 // This file implements the VirtualFileSystem interface.
+//
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/VirtualFileSystem.h"
-#include "clang/Basic/FileManager.h"
+#include "clang/Basic/LLVM.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringExtras.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/Compiler.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Chrono.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 <string>
+#include <system_error>
 #include <utility>
+#include <vector>
 
 using namespace clang;
-using namespace clang::vfs;
+using namespace vfs;
 using namespace llvm;
+
 using llvm::sys::fs::file_status;
 using llvm::sys::fs::file_type;
 using llvm::sys::fs::perms;
@@ -38,13 +65,13 @@ 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()), IsVFSMapped(false)  {}
+      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), IsVFSMapped(false) {}
+      Type(Type), Perms(Perms) {}
 
 Status Status::copyWithNewName(const Status &In, StringRef NewName) {
   return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
@@ -62,28 +89,34 @@ 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() {}
+File::~File() = default;
 
-FileSystem::~FileSystem() {}
+FileSystem::~FileSystem() = default;
 
 ErrorOr<std::unique_ptr<MemoryBuffer>>
 FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
@@ -97,7 +130,7 @@ FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
 
 std::error_code FileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
   if (llvm::sys::path::is_absolute(Path))
-    return std::error_code();
+    return {};
 
   auto WorkingDir = getCurrentWorkingDirectory();
   if (!WorkingDir)
@@ -118,6 +151,7 @@ static bool isTraversalComponent(StringRef Component) {
 
 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;
@@ -130,12 +164,15 @@ static bool pathHasTraversal(StringRef Path) {
 //===-----------------------------------------------------------------------===/
 
 namespace {
+
 /// \brief Wrapper around a raw file descriptor.
 class RealFile : public File {
+  friend class RealFileSystem;
+
   int FD;
   Status S;
   std::string RealName;
-  friend class RealFileSystem;
+
   RealFile(int FD, StringRef NewName, StringRef NewRealPathName)
       : FD(FD), S(NewName, {}, {}, {}, {}, {},
                   llvm::sys::fs::file_type::status_error, {}),
@@ -145,6 +182,7 @@ class RealFile : public File {
 
 public:
   ~RealFile() override;
+
   ErrorOr<Status> status() override;
   ErrorOr<std::string> getName() override;
   ErrorOr<std::unique_ptr<MemoryBuffer>> getBuffer(const Twine &Name,
@@ -153,7 +191,9 @@ public:
                                                    bool IsVolatile) override;
   std::error_code close() override;
 };
-} // end anonymous namespace
+
+} // namespace
+
 RealFile::~RealFile() { close(); }
 
 ErrorOr<Status> RealFile::status() {
@@ -186,6 +226,7 @@ std::error_code RealFile::close() {
 }
 
 namespace {
+
 /// \brief The file system according to your operating system.
 class RealFileSystem : public FileSystem {
 public:
@@ -196,7 +237,8 @@ public:
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
 };
-} // end anonymous namespace
+
+} // namespace
 
 ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
   sys::fs::file_status RealStatus;
@@ -238,8 +280,10 @@ IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
 }
 
 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 (!EC && Iter != llvm::sys::fs::directory_iterator()) {
@@ -264,7 +308,8 @@ public:
     return EC;
   }
 };
-}
+
+} // namespace
 
 directory_iterator RealFileSystem::dir_begin(const Twine &Dir,
                                              std::error_code &EC) {
@@ -274,6 +319,7 @@ directory_iterator RealFileSystem::dir_begin(const Twine &Dir,
 //===-----------------------------------------------------------------------===/
 // OverlayFileSystem implementation
 //===-----------------------------------------------------------------------===/
+
 OverlayFileSystem::OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS) {
   FSList.push_back(std::move(BaseFS));
 }
@@ -311,17 +357,19 @@ 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();
+  return {};
 }
 
-clang::vfs::detail::DirIterImpl::~DirIterImpl() { }
+clang::vfs::detail::DirIterImpl::~DirIterImpl() = default;
 
 namespace {
+
 class OverlayFSDirIterImpl : public clang::vfs::detail::DirIterImpl {
   OverlayFileSystem &Overlays;
   std::string Path;
@@ -340,7 +388,7 @@ class OverlayFSDirIterImpl : public clang::vfs::detail::DirIterImpl {
       if (CurrentDirIter != directory_iterator())
         break; // found
     }
-    return std::error_code();
+    return {};
   }
 
   std::error_code incrementDirIter(bool IsFirstTime) {
@@ -379,7 +427,8 @@ public:
 
   std::error_code increment() override { return incrementImpl(false); }
 };
-} // end anonymous namespace
+
+} // namespace
 
 directory_iterator OverlayFileSystem::dir_begin(const Twine &Dir,
                                                 std::error_code &EC) {
@@ -389,6 +438,7 @@ directory_iterator OverlayFileSystem::dir_begin(const Twine &Dir,
 
 namespace clang {
 namespace vfs {
+
 namespace detail {
 
 enum InMemoryNodeKind { IME_File, IME_Directory };
@@ -402,13 +452,15 @@ class InMemoryNode {
 public:
   InMemoryNode(Status Stat, InMemoryNodeKind Kind)
       : Stat(std::move(Stat)), Kind(Kind) {}
-  virtual ~InMemoryNode() {}
+  virtual ~InMemoryNode() = default;
+
   const Status &getStatus() const { return Stat; }
   InMemoryNodeKind getKind() const { return Kind; }
   virtual std::string toString(unsigned Indent) const = 0;
 };
 
 namespace {
+
 class InMemoryFile : public InMemoryNode {
   std::unique_ptr<llvm::MemoryBuffer> Buffer;
 
@@ -417,9 +469,11 @@ public:
       : InMemoryNode(std::move(Stat), IME_File), Buffer(std::move(Buffer)) {}
 
   llvm::MemoryBuffer *getBuffer() { return Buffer.get(); }
+
   std::string toString(unsigned Indent) const override {
     return (std::string(Indent, ' ') + getStatus().getName() + "\n").str();
   }
+
   static bool classof(const InMemoryNode *N) {
     return N->getKind() == IME_File;
   }
@@ -433,6 +487,7 @@ public:
   explicit InMemoryFileAdaptor(InMemoryFile &Node) : Node(Node) {}
 
   llvm::ErrorOr<Status> status() override { return Node.getStatus(); }
+
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
   getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
             bool IsVolatile) override {
@@ -440,9 +495,11 @@ public:
     return llvm::MemoryBuffer::getMemBuffer(
         Buf->getBuffer(), Buf->getBufferIdentifier(), RequiresNullTerminator);
   }
-  std::error_code close() override { return std::error_code(); }
+
+  std::error_code close() override { return {}; }
 };
-} // end anonymous namespace
+
+} // namespace
 
 class InMemoryDirectory : public InMemoryNode {
   std::map<std::string, std::unique_ptr<InMemoryNode>> Entries;
@@ -450,34 +507,38 @@ class InMemoryDirectory : public InMemoryNode {
 public:
   InMemoryDirectory(Status Stat)
       : InMemoryNode(std::move(Stat), IME_Directory) {}
+
   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();
   }
 
-  typedef decltype(Entries)::const_iterator const_iterator;
+  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, ' ') + getStatus().getName() + "\n").str();
-    for (const auto &Entry : Entries) {
+    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 detail
 
 InMemoryFileSystem::InMemoryFileSystem(bool UseNormalizedPaths)
     : Root(new detail::InMemoryDirectory(
@@ -486,7 +547,7 @@ InMemoryFileSystem::InMemoryFileSystem(bool UseNormalizedPaths)
                  llvm::sys::fs::perms::all_all))),
       UseNormalizedPaths(UseNormalizedPaths) {}
 
-InMemoryFileSystem::~InMemoryFileSystem() {}
+InMemoryFileSystem::~InMemoryFileSystem() = default;
 
 std::string InMemoryFileSystem::toString() const {
   return Root->toString(/*Indent=*/0);
@@ -645,13 +706,15 @@ InMemoryFileSystem::openFileForRead(const Twine &Path) {
 }
 
 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;
 
 public:
-  InMemoryDirIterator() {}
+  InMemoryDirIterator() = default;
+
   explicit InMemoryDirIterator(detail::InMemoryDirectory &Dir)
       : I(Dir.begin()), E(Dir.end()) {
     if (I != E)
@@ -663,10 +726,11 @@ public:
     // When we're at the end, make CurrentEntry invalid and DirIterImpl will do
     // the rest.
     CurrentEntry = I != E ? I->second->getStatus() : Status();
-    return std::error_code();
+    return {};
   }
 };
-} // end anonymous namespace
+
+} // namespace
 
 directory_iterator InMemoryFileSystem::dir_begin(const Twine &Dir,
                                                  std::error_code &EC) {
@@ -697,11 +761,12 @@ std::error_code InMemoryFileSystem::setCurrentWorkingDirectory(const Twine &P) {
 
   if (!Path.empty())
     WorkingDirectory = Path.str();
-  return std::error_code();
-}
-}
+  return {};
 }
 
+} // namespace vfs
+} // namespace clang
+
 //===-----------------------------------------------------------------------===/
 // RedirectingFileSystem implementation
 //===-----------------------------------------------------------------------===/
@@ -719,8 +784,9 @@ class Entry {
   std::string Name;
 
 public:
-  virtual ~Entry();
   Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {}
+  virtual ~Entry() = default;
+
   StringRef getName() const { return Name; }
   EntryKind getKind() const { return Kind; }
 };
@@ -737,14 +803,20 @@ public:
         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(); }
-  typedef decltype(Contents)::iterator iterator;
+
+  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; }
 };
 
@@ -755,21 +827,27 @@ public:
     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; }
+
   /// \brief 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; }
 };
 
@@ -785,6 +863,7 @@ public:
                          RedirectingDirectoryEntry::iterator Begin,
                          RedirectingDirectoryEntry::iterator End,
                          std::error_code &EC);
+
   std::error_code increment() override;
 };
 
@@ -844,10 +923,14 @@ public:
 /// /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;
+
   /// \brief 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.
@@ -888,8 +971,6 @@ class RedirectingFileSystem : public vfs::FileSystem {
       true;
 #endif
 
-  friend class RedirectingFileSystemParser;
-
 private:
   RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> ExternalFS)
       : ExternalFS(std::move(ExternalFS)) {}
@@ -919,6 +1000,7 @@ public:
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
     return ExternalFS->getCurrentWorkingDirectory();
   }
+
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
     return ExternalFS->setCurrentWorkingDirectory(Path);
   }
@@ -927,17 +1009,17 @@ public:
     ErrorOr<Entry *> E = lookupPath(Dir);
     if (!E) {
       EC = E.getError();
-      return directory_iterator();
+      return {};
     }
     ErrorOr<Status> S = status(Dir, *E);
     if (!S) {
       EC = S.getError();
-      return directory_iterator();
+      return {};
     }
     if (!S->isDirectory()) {
       EC = std::error_code(static_cast<int>(errc::not_a_directory),
                            std::system_category());
-      return directory_iterator();
+      return {};
     }
 
     auto *D = cast<RedirectingDirectoryEntry>(*E);
@@ -959,7 +1041,7 @@ public:
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void dump() const {
-    for (const std::unique_ptr<Entry> &Root : Roots)
+    for (const auto &Root : Roots)
       dumpEntry(Root.get());
   }
 
@@ -979,7 +1061,6 @@ LLVM_DUMP_METHOD void dumpEntry(Entry *E, int NumSpaces = 0) const {
     }
   }
 #endif
-
 };
 
 /// \brief A helper class to hold the common YAML parsing state.
@@ -993,7 +1074,8 @@ class RedirectingFileSystemParser {
   // false on error
   bool parseScalarString(yaml::Node *N, StringRef &Result,
                          SmallVectorImpl<char> &Storage) {
-    yaml::ScalarNode *S = dyn_cast<yaml::ScalarNode>(N);
+    const auto *S = dyn_cast<yaml::ScalarNode>(N);
+
     if (!S) {
       error(N, "expected string");
       return false;
@@ -1024,11 +1106,13 @@ class RedirectingFileSystemParser {
   }
 
   struct KeyStatus {
-    KeyStatus(bool Required=false) : Required(Required), Seen(false) {}
     bool Required;
-    bool Seen;
+    bool Seen = false;
+
+    KeyStatus(bool Required = false) : Required(Required) {}
   };
-  typedef std::pair<StringRef, KeyStatus> KeyStatusPair;
+
+  using KeyStatusPair = std::pair<StringRef, KeyStatus>;
 
   // false on error
   bool checkDuplicateOrUnknownKey(yaml::Node *KeyNode, StringRef Key,
@@ -1048,11 +1132,9 @@ class RedirectingFileSystemParser {
 
   // false on error
   bool checkMissingKeys(yaml::Node *Obj, DenseMap<StringRef, KeyStatus> &Keys) {
-    for (DenseMap<StringRef, KeyStatus>::iterator I = Keys.begin(),
-         E = Keys.end();
-         I != E; ++I) {
-      if (I->second.Required && !I->second.Seen) {
-        error(Obj, Twine("missing key '") + I->first + "'");
+    for (const auto &I : Keys) {
+      if (I.second.Required && !I.second.Seen) {
+        error(Obj, Twine("missing key '") + I.first + "'");
         return false;
       }
     }
@@ -1062,7 +1144,7 @@ class RedirectingFileSystemParser {
   Entry *lookupOrCreateEntry(RedirectingFileSystem *FS, StringRef Name,
                              Entry *ParentEntry = nullptr) {
     if (!ParentEntry) { // Look for a existent root
-      for (const std::unique_ptr<Entry> &Root : FS->Roots) {
+      for (const auto &Root : FS->Roots) {
         if (Name.equals(Root->getName())) {
           ParentEntry = Root.get();
           return ParentEntry;
@@ -1125,7 +1207,7 @@ class RedirectingFileSystemParser {
   }
 
   std::unique_ptr<Entry> parseEntry(yaml::Node *N, RedirectingFileSystem *FS) {
-    yaml::MappingNode *M = dyn_cast<yaml::MappingNode>(N);
+    auto *M = dyn_cast<yaml::MappingNode>(N);
     if (!M) {
       error(N, "expected mapping node for file or directory entry");
       return nullptr;
@@ -1148,21 +1230,20 @@ class RedirectingFileSystemParser {
     auto UseExternalName = RedirectingFileEntry::NK_NotSet;
     EntryKind Kind;
 
-    for (yaml::MappingNode::iterator I = M->begin(), E = M->end(); I != E;
-         ++I) {
+    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))
+      if (!parseScalarString(I.getKey(), Key, Buffer))
         return nullptr;
 
-      if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
+      if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
         return nullptr;
 
       StringRef Value;
       if (Key == "name") {
-        if (!parseScalarString(I->getValue(), Value, Buffer))
+        if (!parseScalarString(I.getValue(), Value, Buffer))
           return nullptr;
 
         if (FS->UseCanonicalizedPaths) {
@@ -1176,47 +1257,44 @@ class RedirectingFileSystemParser {
           Name = Value;
         }
       } else if (Key == "type") {
-        if (!parseScalarString(I->getValue(), Value, Buffer))
+        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'");
+          error(I.getValue(), "unknown value for 'type'");
           return nullptr;
         }
       } else if (Key == "contents") {
         if (HasContents) {
-          error(I->getKey(),
+          error(I.getKey(),
                 "entry already has 'contents' or 'external-contents'");
           return nullptr;
         }
         HasContents = true;
-        yaml::SequenceNode *Contents =
-            dyn_cast<yaml::SequenceNode>(I->getValue());
+        auto *Contents = dyn_cast<yaml::SequenceNode>(I.getValue());
         if (!Contents) {
           // FIXME: this is only for directories, what about files?
-          error(I->getValue(), "expected array");
+          error(I.getValue(), "expected array");
           return nullptr;
         }
 
-        for (yaml::SequenceNode::iterator I = Contents->begin(),
-                                          E = Contents->end();
-             I != E; ++I) {
-          if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
+        for (auto &I : *Contents) {
+          if (std::unique_ptr<Entry> E = parseEntry(&I, FS))
             EntryArrayContents.push_back(std::move(E));
           else
             return nullptr;
         }
       } else if (Key == "external-contents") {
         if (HasContents) {
-          error(I->getKey(),
+          error(I.getKey(),
                 "entry already has 'contents' or 'external-contents'");
           return nullptr;
         }
         HasContents = true;
-        if (!parseScalarString(I->getValue(), Value, Buffer))
+        if (!parseScalarString(I.getValue(), Value, Buffer))
           return nullptr;
 
         SmallString<256> FullPath;
@@ -1238,7 +1316,7 @@ class RedirectingFileSystemParser {
         ExternalContentsPath = FullPath.str();
       } else if (Key == "use-external-name") {
         bool Val;
-        if (!parseScalarBool(I->getValue(), Val))
+        if (!parseScalarBool(I.getValue(), Val))
           return nullptr;
         UseExternalName = Val ? RedirectingFileEntry::NK_External
                               : RedirectingFileEntry::NK_Virtual;
@@ -1311,7 +1389,7 @@ public:
 
   // false on error
   bool parse(yaml::Node *Root, RedirectingFileSystem *FS) {
-    yaml::MappingNode *Top = dyn_cast<yaml::MappingNode>(Root);
+    auto *Top = dyn_cast<yaml::MappingNode>(Root);
     if (!Top) {
       error(Root, "expected mapping node");
       return false;
@@ -1330,26 +1408,24 @@ public:
     std::vector<std::unique_ptr<Entry>> RootEntries;
 
     // Parse configuration and 'roots'
-    for (yaml::MappingNode::iterator I = Top->begin(), E = Top->end(); I != E;
-         ++I) {
+    for (auto &I : *Top) {
       SmallString<10> KeyBuffer;
       StringRef Key;
-      if (!parseScalarString(I->getKey(), Key, KeyBuffer))
+      if (!parseScalarString(I.getKey(), Key, KeyBuffer))
         return false;
 
-      if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
+      if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
         return false;
 
       if (Key == "roots") {
-        yaml::SequenceNode *Roots = dyn_cast<yaml::SequenceNode>(I->getValue());
+        auto *Roots = dyn_cast<yaml::SequenceNode>(I.getValue());
         if (!Roots) {
-          error(I->getValue(), "expected array");
+          error(I.getValue(), "expected array");
           return false;
         }
 
-        for (yaml::SequenceNode::iterator I = Roots->begin(), E = Roots->end();
-             I != E; ++I) {
-          if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
+        for (auto &I : *Roots) {
+          if (std::unique_ptr<Entry> E = parseEntry(&I, FS))
             RootEntries.push_back(std::move(E));
           else
             return false;
@@ -1357,32 +1433,32 @@ public:
       } else if (Key == "version") {
         StringRef VersionString;
         SmallString<4> Storage;
-        if (!parseScalarString(I->getValue(), VersionString, Storage))
+        if (!parseScalarString(I.getValue(), VersionString, Storage))
           return false;
         int Version;
         if (VersionString.getAsInteger<int>(10, Version)) {
-          error(I->getValue(), "expected integer");
+          error(I.getValue(), "expected integer");
           return false;
         }
         if (Version < 0) {
-          error(I->getValue(), "invalid version number");
+          error(I.getValue(), "invalid version number");
           return false;
         }
         if (Version != 0) {
-          error(I->getValue(), "version mismatch, expected 0");
+          error(I.getValue(), "version mismatch, expected 0");
           return false;
         }
       } else if (Key == "case-sensitive") {
-        if (!parseScalarBool(I->getValue(), FS->CaseSensitive))
+        if (!parseScalarBool(I.getValue(), FS->CaseSensitive))
           return false;
       } else if (Key == "overlay-relative") {
-        if (!parseScalarBool(I->getValue(), FS->IsRelativeOverlay))
+        if (!parseScalarBool(I.getValue(), FS->IsRelativeOverlay))
           return false;
       } else if (Key == "use-external-names") {
-        if (!parseScalarBool(I->getValue(), FS->UseExternalNames))
+        if (!parseScalarBool(I.getValue(), FS->UseExternalNames))
           return false;
       } else if (Key == "ignore-non-existent-contents") {
-        if (!parseScalarBool(I->getValue(), FS->IgnoreNonExistentContents))
+        if (!parseScalarBool(I.getValue(), FS->IgnoreNonExistentContents))
           return false;
       } else {
         llvm_unreachable("key missing from Keys");
@@ -1398,22 +1474,20 @@ public:
     // 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 (std::unique_ptr<Entry> &E : RootEntries)
+    for (auto &E : RootEntries)
       uniqueOverlayTree(FS, E.get());
 
     return true;
   }
 };
-} // end of anonymous namespace
 
-Entry::~Entry() = default;
+} // 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);
 
@@ -1473,7 +1547,7 @@ ErrorOr<Entry *> RedirectingFileSystem::lookupPath(const Twine &Path_) {
 
   sys::path::const_iterator Start = sys::path::begin(Path);
   sys::path::const_iterator End = sys::path::end(Path);
-  for (const std::unique_ptr<Entry> &Root : Roots) {
+  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;
@@ -1557,6 +1631,7 @@ ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path) {
 }
 
 namespace {
+
 /// Provide a file wrapper with an overriden status.
 class FileWithFixedStatus : public File {
   std::unique_ptr<File> InnerFile;
@@ -1568,14 +1643,17 @@ public:
 
   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(); }
 };
-} // end anonymous namespace
+
+} // namespace
 
 ErrorOr<std::unique_ptr<File>>
 RedirectingFileSystem::openFileForRead(const Twine &Path) {
@@ -1670,11 +1748,13 @@ void YAMLVFSWriter::addFileMapping(StringRef VirtualPath, StringRef RealPath) {
 }
 
 namespace {
+
 class JSONWriter {
   llvm::raw_ostream &OS;
   SmallVector<StringRef, 16> DirStack;
-  inline unsigned getDirIndent() { return 4 * DirStack.size(); }
-  inline unsigned getFileIndent() { return 4 * (DirStack.size() + 1); }
+
+  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);
@@ -1683,14 +1763,17 @@ class JSONWriter {
 
 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);
@@ -1868,7 +1951,7 @@ std::error_code VFSFromYamlDirIterImpl::increment() {
 
   if (Current == End)
     CurrentEntry = Status();
-  return std::error_code();
+  return {};
 }
 
 vfs::recursive_directory_iterator::recursive_directory_iterator(FileSystem &FS_,