Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 891 insertions, 0 deletions

diff --git a/clang-r353983/include/clang/Frontend/ASTUnit.h b/clang-r353983/include/clang/Frontend/ASTUnit.h
new file mode 100644
index 00000000..cef638e2
--- /dev/null
+++ b/clang-r353983/include/clang/Frontend/ASTUnit.h
@@ -0,0 +1,891 @@
+//===- ASTUnit.h - ASTUnit utility ------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// ASTUnit utility class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_FRONTEND_ASTUNIT_H
+#define LLVM_CLANG_FRONTEND_ASTUNIT_H
+
+#include "clang-c/Index.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/FileSystemOptions.h"
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/TargetOptions.h"
+#include "clang/Lex/HeaderSearchOptions.h"
+#include "clang/Lex/ModuleLoader.h"
+#include "clang/Lex/PreprocessingRecord.h"
+#include "clang/Sema/CodeCompleteConsumer.h"
+#include "clang/Serialization/ASTBitCodes.h"
+#include "clang/Frontend/PrecompiledPreamble.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/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/iterator_range.h"
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+class MemoryBuffer;
+
+namespace vfs {
+
+class FileSystem;
+
+} // namespace vfs
+} // namespace llvm
+
+namespace clang {
+
+class ASTContext;
+class ASTDeserializationListener;
+class ASTMutationListener;
+class ASTReader;
+class CompilerInstance;
+class CompilerInvocation;
+class Decl;
+class FileEntry;
+class FileManager;
+class FrontendAction;
+class HeaderSearch;
+class InputKind;
+class MemoryBufferCache;
+class PCHContainerOperations;
+class PCHContainerReader;
+class Preprocessor;
+class PreprocessorOptions;
+class Sema;
+class TargetInfo;
+
+/// \brief Enumerates the available scopes for skipping function bodies.
+enum class SkipFunctionBodiesScope { None, Preamble, PreambleAndMainFile };
+
+/// Utility class for loading a ASTContext from an AST file.
+class ASTUnit {
+public:
+  struct StandaloneFixIt {
+    std::pair<unsigned, unsigned> RemoveRange;
+    std::pair<unsigned, unsigned> InsertFromRange;
+    std::string CodeToInsert;
+    bool BeforePreviousInsertions;
+  };
+
+  struct StandaloneDiagnostic {
+    unsigned ID;
+    DiagnosticsEngine::Level Level;
+    std::string Message;
+    std::string Filename;
+    unsigned LocOffset;
+    std::vector<std::pair<unsigned, unsigned>> Ranges;
+    std::vector<StandaloneFixIt> FixIts;
+  };
+
+private:
+  std::shared_ptr<LangOptions>            LangOpts;
+  IntrusiveRefCntPtr<DiagnosticsEngine>   Diagnostics;
+  IntrusiveRefCntPtr<FileManager>         FileMgr;
+  IntrusiveRefCntPtr<SourceManager>       SourceMgr;
+  IntrusiveRefCntPtr<MemoryBufferCache>   PCMCache;
+  std::unique_ptr<HeaderSearch>           HeaderInfo;
+  IntrusiveRefCntPtr<TargetInfo>          Target;
+  std::shared_ptr<Preprocessor>           PP;
+  IntrusiveRefCntPtr<ASTContext>          Ctx;
+  std::shared_ptr<TargetOptions>          TargetOpts;
+  std::shared_ptr<HeaderSearchOptions>    HSOpts;
+  std::shared_ptr<PreprocessorOptions>    PPOpts;
+  IntrusiveRefCntPtr<ASTReader> Reader;
+  bool HadModuleLoaderFatalFailure = false;
+
+  struct ASTWriterData;
+  std::unique_ptr<ASTWriterData> WriterData;
+
+  FileSystemOptions FileSystemOpts;
+
+  /// The AST consumer that received information about the translation
+  /// unit as it was parsed or loaded.
+  std::unique_ptr<ASTConsumer> Consumer;
+
+  /// The semantic analysis object used to type-check the translation
+  /// unit.
+  std::unique_ptr<Sema> TheSema;
+
+  /// Optional owned invocation, just used to make the invocation used in
+  /// LoadFromCommandLine available.
+  std::shared_ptr<CompilerInvocation> Invocation;
+
+  /// Fake module loader: the AST unit doesn't need to load any modules.
+  TrivialModuleLoader ModuleLoader;
+
+  // OnlyLocalDecls - when true, walking this AST should only visit declarations
+  // that come from the AST itself, not from included precompiled headers.
+  // FIXME: This is temporary; eventually, CIndex will always do this.
+  bool OnlyLocalDecls = false;
+
+  /// Whether to capture any diagnostics produced.
+  bool CaptureDiagnostics = false;
+
+  /// Track whether the main file was loaded from an AST or not.
+  bool MainFileIsAST;
+
+  /// What kind of translation unit this AST represents.
+  TranslationUnitKind TUKind = TU_Complete;
+
+  /// Whether we should time each operation.
+  bool WantTiming;
+
+  /// Whether the ASTUnit should delete the remapped buffers.
+  bool OwnsRemappedFileBuffers = true;
+
+  /// Track the top-level decls which appeared in an ASTUnit which was loaded
+  /// from a source file.
+  //
+  // FIXME: This is just an optimization hack to avoid deserializing large parts
+  // of a PCH file when using the Index library on an ASTUnit loaded from
+  // source. In the long term we should make the Index library use efficient and
+  // more scalable search mechanisms.
+  std::vector<Decl*> TopLevelDecls;
+
+  /// Sorted (by file offset) vector of pairs of file offset/Decl.
+  using LocDeclsTy = SmallVector<std::pair<unsigned, Decl *>, 64>;
+  using FileDeclsTy = llvm::DenseMap<FileID, LocDeclsTy *>;
+
+  /// Map from FileID to the file-level declarations that it contains.
+  /// The files and decls are only local (and non-preamble) ones.
+  FileDeclsTy FileDecls;
+
+  /// The name of the original source file used to generate this ASTUnit.
+  std::string OriginalSourceFile;
+
+  /// The set of diagnostics produced when creating the preamble.
+  SmallVector<StandaloneDiagnostic, 4> PreambleDiagnostics;
+
+  /// The set of diagnostics produced when creating this
+  /// translation unit.
+  SmallVector<StoredDiagnostic, 4> StoredDiagnostics;
+
+  /// The set of diagnostics produced when failing to parse, e.g. due
+  /// to failure to load the PCH.
+  SmallVector<StoredDiagnostic, 4> FailedParseDiagnostics;
+
+  /// The number of stored diagnostics that come from the driver
+  /// itself.
+  ///
+  /// Diagnostics that come from the driver are retained from one parse to
+  /// the next.
+  unsigned NumStoredDiagnosticsFromDriver = 0;
+
+  /// Counter that determines when we want to try building a
+  /// precompiled preamble.
+  ///
+  /// If zero, we will never build a precompiled preamble. Otherwise,
+  /// it's treated as a counter that decrements each time we reparse
+  /// without the benefit of a precompiled preamble. When it hits 1,
+  /// we'll attempt to rebuild the precompiled header. This way, if
+  /// building the precompiled preamble fails, we won't try again for
+  /// some number of calls.
+  unsigned PreambleRebuildCounter = 0;
+
+  /// Cache pairs "filename - source location"
+  ///
+  /// Cache contains only source locations from preamble so it is
+  /// guaranteed that they stay valid when the SourceManager is recreated.
+  /// This cache is used when loading preamble to increase performance
+  /// of that loading. It must be cleared when preamble is recreated.
+  llvm::StringMap<SourceLocation> PreambleSrcLocCache;
+
+  /// The contents of the preamble.
+  llvm::Optional<PrecompiledPreamble> Preamble;
+
+  /// When non-NULL, this is the buffer used to store the contents of
+  /// the main file when it has been padded for use with the precompiled
+  /// preamble.
+  std::unique_ptr<llvm::MemoryBuffer> SavedMainFileBuffer;
+
+  /// The number of warnings that occurred while parsing the preamble.
+  ///
+  /// This value will be used to restore the state of the \c DiagnosticsEngine
+  /// object when re-using the precompiled preamble. Note that only the
+  /// number of warnings matters, since we will not save the preamble
+  /// when any errors are present.
+  unsigned NumWarningsInPreamble = 0;
+
+  /// A list of the serialization ID numbers for each of the top-level
+  /// declarations parsed within the precompiled preamble.
+  std::vector<serialization::DeclID> TopLevelDeclsInPreamble;
+
+  /// Whether we should be caching code-completion results.
+  bool ShouldCacheCodeCompletionResults : 1;
+
+  /// Whether to include brief documentation within the set of code
+  /// completions cached.
+  bool IncludeBriefCommentsInCodeCompletion : 1;
+
+  /// True if non-system source files should be treated as volatile
+  /// (likely to change while trying to use them).
+  bool UserFilesAreVolatile : 1;
+
+  static void ConfigureDiags(IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+                             ASTUnit &AST, bool CaptureDiagnostics);
+
+  void TranslateStoredDiagnostics(FileManager &FileMgr,
+                                  SourceManager &SrcMan,
+                      const SmallVectorImpl<StandaloneDiagnostic> &Diags,
+                            SmallVectorImpl<StoredDiagnostic> &Out);
+
+  void clearFileLevelDecls();
+
+public:
+  /// A cached code-completion result, which may be introduced in one of
+  /// many different contexts.
+  struct CachedCodeCompletionResult {
+    /// The code-completion string corresponding to this completion
+    /// result.
+    CodeCompletionString *Completion;
+
+    /// A bitmask that indicates which code-completion contexts should
+    /// contain this completion result.
+    ///
+    /// The bits in the bitmask correspond to the values of
+    /// CodeCompleteContext::Kind. To map from a completion context kind to a
+    /// bit, shift 1 by that number of bits. Many completions can occur in
+    /// several different contexts.
+    uint64_t ShowInContexts;
+
+    /// The priority given to this code-completion result.
+    unsigned Priority;
+
+    /// The libclang cursor kind corresponding to this code-completion
+    /// result.
+    CXCursorKind Kind;
+
+    /// The availability of this code-completion result.
+    CXAvailabilityKind Availability;
+
+    /// The simplified type class for a non-macro completion result.
+    SimplifiedTypeClass TypeClass;
+
+    /// The type of a non-macro completion result, stored as a unique
+    /// integer used by the string map of cached completion types.
+    ///
+    /// This value will be zero if the type is not known, or a unique value
+    /// determined by the formatted type string. Se \c CachedCompletionTypes
+    /// for more information.
+    unsigned Type;
+  };
+
+  /// Retrieve the mapping from formatted type names to unique type
+  /// identifiers.
+  llvm::StringMap<unsigned> &getCachedCompletionTypes() {
+    return CachedCompletionTypes;
+  }
+
+  /// Retrieve the allocator used to cache global code completions.
+  std::shared_ptr<GlobalCodeCompletionAllocator>
+  getCachedCompletionAllocator() {
+    return CachedCompletionAllocator;
+  }
+
+  CodeCompletionTUInfo &getCodeCompletionTUInfo() {
+    if (!CCTUInfo)
+      CCTUInfo = llvm::make_unique<CodeCompletionTUInfo>(
+          std::make_shared<GlobalCodeCompletionAllocator>());
+    return *CCTUInfo;
+  }
+
+private:
+  /// Allocator used to store cached code completions.
+  std::shared_ptr<GlobalCodeCompletionAllocator> CachedCompletionAllocator;
+
+  std::unique_ptr<CodeCompletionTUInfo> CCTUInfo;
+
+  /// The set of cached code-completion results.
+  std::vector<CachedCodeCompletionResult> CachedCompletionResults;
+
+  /// A mapping from the formatted type name to a unique number for that
+  /// type, which is used for type equality comparisons.
+  llvm::StringMap<unsigned> CachedCompletionTypes;
+
+  /// A string hash of the top-level declaration and macro definition
+  /// names processed the last time that we reparsed the file.
+  ///
+  /// This hash value is used to determine when we need to refresh the
+  /// global code-completion cache.
+  unsigned CompletionCacheTopLevelHashValue = 0;
+
+  /// A string hash of the top-level declaration and macro definition
+  /// names processed the last time that we reparsed the precompiled preamble.
+  ///
+  /// This hash value is used to determine when we need to refresh the
+  /// global code-completion cache after a rebuild of the precompiled preamble.
+  unsigned PreambleTopLevelHashValue = 0;
+
+  /// The current hash value for the top-level declaration and macro
+  /// definition names
+  unsigned CurrentTopLevelHashValue = 0;
+
+  /// Bit used by CIndex to mark when a translation unit may be in an
+  /// inconsistent state, and is not safe to free.
+  unsigned UnsafeToFree : 1;
+
+  /// \brief Enumerator specifying the scope for skipping function bodies.
+  SkipFunctionBodiesScope SkipFunctionBodies = SkipFunctionBodiesScope::None;
+
+  /// Cache any "global" code-completion results, so that we can avoid
+  /// recomputing them with each completion.
+  void CacheCodeCompletionResults();
+
+  /// Clear out and deallocate
+  void ClearCachedCompletionResults();
+
+  explicit ASTUnit(bool MainFileIsAST);
+
+  bool Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+             std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer,
+             IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS);
+
+  std::unique_ptr<llvm::MemoryBuffer> getMainBufferWithPrecompiledPreamble(
+      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+      CompilerInvocation &PreambleInvocationIn,
+      IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool AllowRebuild = true,
+      unsigned MaxLines = 0);
+  void RealizeTopLevelDeclsFromPreamble();
+
+  /// Transfers ownership of the objects (like SourceManager) from
+  /// \param CI to this ASTUnit.
+  void transferASTDataFromCompilerInstance(CompilerInstance &CI);
+
+  /// Allows us to assert that ASTUnit is not being used concurrently,
+  /// which is not supported.
+  ///
+  /// Clients should create instances of the ConcurrencyCheck class whenever
+  /// using the ASTUnit in a way that isn't intended to be concurrent, which is
+  /// just about any usage.
+  /// Becomes a noop in release mode; only useful for debug mode checking.
+  class ConcurrencyState {
+    void *Mutex; // a llvm::sys::MutexImpl in debug;
+
+  public:
+    ConcurrencyState();
+    ~ConcurrencyState();
+
+    void start();
+    void finish();
+  };
+  ConcurrencyState ConcurrencyCheckValue;
+
+public:
+  friend class ConcurrencyCheck;
+
+  class ConcurrencyCheck {
+    ASTUnit &Self;
+
+  public:
+    explicit ConcurrencyCheck(ASTUnit &Self) : Self(Self) {
+      Self.ConcurrencyCheckValue.start();
+    }
+
+    ~ConcurrencyCheck() {
+      Self.ConcurrencyCheckValue.finish();
+    }
+  };
+
+  ASTUnit(const ASTUnit &) = delete;
+  ASTUnit &operator=(const ASTUnit &) = delete;
+  ~ASTUnit();
+
+  bool isMainFileAST() const { return MainFileIsAST; }
+
+  bool isUnsafeToFree() const { return UnsafeToFree; }
+  void setUnsafeToFree(bool Value) { UnsafeToFree = Value; }
+
+  const DiagnosticsEngine &getDiagnostics() const { return *Diagnostics; }
+  DiagnosticsEngine &getDiagnostics() { return *Diagnostics; }
+
+  const SourceManager &getSourceManager() const { return *SourceMgr; }
+  SourceManager &getSourceManager() { return *SourceMgr; }
+
+  const Preprocessor &getPreprocessor() const { return *PP; }
+  Preprocessor &getPreprocessor() { return *PP; }
+  std::shared_ptr<Preprocessor> getPreprocessorPtr() const { return PP; }
+
+  const ASTContext &getASTContext() const { return *Ctx; }
+  ASTContext &getASTContext() { return *Ctx; }
+
+  void setASTContext(ASTContext *ctx) { Ctx = ctx; }
+  void setPreprocessor(std::shared_ptr<Preprocessor> pp);
+
+  /// Enable source-range based diagnostic messages.
+  ///
+  /// If diagnostic messages with source-range information are to be expected
+  /// and AST comes not from file (e.g. after LoadFromCompilerInvocation) this
+  /// function has to be called.
+  /// The function is to be called only once and the AST should be associated
+  /// with the same source file afterwards.
+  void enableSourceFileDiagnostics();
+
+  bool hasSema() const { return (bool)TheSema; }
+
+  Sema &getSema() const {
+    assert(TheSema && "ASTUnit does not have a Sema object!");
+    return *TheSema;
+  }
+
+  const LangOptions &getLangOpts() const {
+    assert(LangOpts && "ASTUnit does not have language options");
+    return *LangOpts;
+  }
+
+  const HeaderSearchOptions &getHeaderSearchOpts() const {
+    assert(HSOpts && "ASTUnit does not have header search options");
+    return *HSOpts;
+  }
+
+  const PreprocessorOptions &getPreprocessorOpts() const {
+    assert(PPOpts && "ASTUnit does not have preprocessor options");
+    return *PPOpts;
+  }
+
+  const FileManager &getFileManager() const { return *FileMgr; }
+  FileManager &getFileManager() { return *FileMgr; }
+
+  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
+
+  IntrusiveRefCntPtr<ASTReader> getASTReader() const;
+
+  StringRef getOriginalSourceFileName() const {
+    return OriginalSourceFile;
+  }
+
+  ASTMutationListener *getASTMutationListener();
+  ASTDeserializationListener *getDeserializationListener();
+
+  bool getOnlyLocalDecls() const { return OnlyLocalDecls; }
+
+  bool getOwnsRemappedFileBuffers() const { return OwnsRemappedFileBuffers; }
+  void setOwnsRemappedFileBuffers(bool val) { OwnsRemappedFileBuffers = val; }
+
+  StringRef getMainFileName() const;
+
+  /// If this ASTUnit came from an AST file, returns the filename for it.
+  StringRef getASTFileName() const;
+
+  using top_level_iterator = std::vector<Decl *>::iterator;
+
+  top_level_iterator top_level_begin() {
+    assert(!isMainFileAST() && "Invalid call for AST based ASTUnit!");
+    if (!TopLevelDeclsInPreamble.empty())
+      RealizeTopLevelDeclsFromPreamble();
+    return TopLevelDecls.begin();
+  }
+
+  top_level_iterator top_level_end() {
+    assert(!isMainFileAST() && "Invalid call for AST based ASTUnit!");
+    if (!TopLevelDeclsInPreamble.empty())
+      RealizeTopLevelDeclsFromPreamble();
+    return TopLevelDecls.end();
+  }
+
+  std::size_t top_level_size() const {
+    assert(!isMainFileAST() && "Invalid call for AST based ASTUnit!");
+    return TopLevelDeclsInPreamble.size() + TopLevelDecls.size();
+  }
+
+  bool top_level_empty() const {
+    assert(!isMainFileAST() && "Invalid call for AST based ASTUnit!");
+    return TopLevelDeclsInPreamble.empty() && TopLevelDecls.empty();
+  }
+
+  /// Add a new top-level declaration.
+  void addTopLevelDecl(Decl *D) {
+    TopLevelDecls.push_back(D);
+  }
+
+  /// Add a new local file-level declaration.
+  void addFileLevelDecl(Decl *D);
+
+  /// Get the decls that are contained in a file in the Offset/Length
+  /// range. \p Length can be 0 to indicate a point at \p Offset instead of
+  /// a range.
+  void findFileRegionDecls(FileID File, unsigned Offset, unsigned Length,
+                           SmallVectorImpl<Decl *> &Decls);
+
+  /// Retrieve a reference to the current top-level name hash value.
+  ///
+  /// Note: This is used internally by the top-level tracking action
+  unsigned &getCurrentTopLevelHashValue() { return CurrentTopLevelHashValue; }
+
+  /// Get the source location for the given file:line:col triplet.
+  ///
+  /// The difference with SourceManager::getLocation is that this method checks
+  /// whether the requested location points inside the precompiled preamble
+  /// in which case the returned source location will be a "loaded" one.
+  SourceLocation getLocation(const FileEntry *File,
+                             unsigned Line, unsigned Col) const;
+
+  /// Get the source location for the given file:offset pair.
+  SourceLocation getLocation(const FileEntry *File, unsigned Offset) const;
+
+  /// If \p Loc is a loaded location from the preamble, returns
+  /// the corresponding local location of the main file, otherwise it returns
+  /// \p Loc.
+  SourceLocation mapLocationFromPreamble(SourceLocation Loc) const;
+
+  /// If \p Loc is a local location of the main file but inside the
+  /// preamble chunk, returns the corresponding loaded location from the
+  /// preamble, otherwise it returns \p Loc.
+  SourceLocation mapLocationToPreamble(SourceLocation Loc) const;
+
+  bool isInPreambleFileID(SourceLocation Loc) const;
+  bool isInMainFileID(SourceLocation Loc) const;
+  SourceLocation getStartOfMainFileID() const;
+  SourceLocation getEndOfPreambleFileID() const;
+
+  /// \see mapLocationFromPreamble.
+  SourceRange mapRangeFromPreamble(SourceRange R) const {
+    return SourceRange(mapLocationFromPreamble(R.getBegin()),
+                       mapLocationFromPreamble(R.getEnd()));
+  }
+
+  /// \see mapLocationToPreamble.
+  SourceRange mapRangeToPreamble(SourceRange R) const {
+    return SourceRange(mapLocationToPreamble(R.getBegin()),
+                       mapLocationToPreamble(R.getEnd()));
+  }
+
+  // Retrieve the diagnostics associated with this AST
+  using stored_diag_iterator = StoredDiagnostic *;
+  using stored_diag_const_iterator = const StoredDiagnostic *;
+
+  stored_diag_const_iterator stored_diag_begin() const {
+    return StoredDiagnostics.begin();
+  }
+
+  stored_diag_iterator stored_diag_begin() {
+    return StoredDiagnostics.begin();
+  }
+
+  stored_diag_const_iterator stored_diag_end() const {
+    return StoredDiagnostics.end();
+  }
+
+  stored_diag_iterator stored_diag_end() {
+    return StoredDiagnostics.end();
+  }
+
+  unsigned stored_diag_size() const { return StoredDiagnostics.size(); }
+
+  stored_diag_iterator stored_diag_afterDriver_begin() {
+    if (NumStoredDiagnosticsFromDriver > StoredDiagnostics.size())
+      NumStoredDiagnosticsFromDriver = 0;
+    return StoredDiagnostics.begin() + NumStoredDiagnosticsFromDriver;
+  }
+
+  using cached_completion_iterator =
+      std::vector<CachedCodeCompletionResult>::iterator;
+
+  cached_completion_iterator cached_completion_begin() {
+    return CachedCompletionResults.begin();
+  }
+
+  cached_completion_iterator cached_completion_end() {
+    return CachedCompletionResults.end();
+  }
+
+  unsigned cached_completion_size() const {
+    return CachedCompletionResults.size();
+  }
+
+  /// Returns an iterator range for the local preprocessing entities
+  /// of the local Preprocessor, if this is a parsed source file, or the loaded
+  /// preprocessing entities of the primary module if this is an AST file.
+  llvm::iterator_range<PreprocessingRecord::iterator>
+  getLocalPreprocessingEntities() const;
+
+  /// Type for a function iterating over a number of declarations.
+  /// \returns true to continue iteration and false to abort.
+  using DeclVisitorFn = bool (*)(void *context, const Decl *D);
+
+  /// Iterate over local declarations (locally parsed if this is a parsed
+  /// source file or the loaded declarations of the primary module if this is an
+  /// AST file).
+  /// \returns true if the iteration was complete or false if it was aborted.
+  bool visitLocalTopLevelDecls(void *context, DeclVisitorFn Fn);
+
+  /// Get the PCH file if one was included.
+  const FileEntry *getPCHFile();
+
+  /// Returns true if the ASTUnit was constructed from a serialized
+  /// module file.
+  bool isModuleFile() const;
+
+  std::unique_ptr<llvm::MemoryBuffer>
+  getBufferForFile(StringRef Filename, std::string *ErrorStr = nullptr);
+
+  /// Determine what kind of translation unit this AST represents.
+  TranslationUnitKind getTranslationUnitKind() const { return TUKind; }
+
+  /// Determine the input kind this AST unit represents.
+  InputKind getInputKind() const;
+
+  /// A mapping from a file name to the memory buffer that stores the
+  /// remapped contents of that file.
+  using RemappedFile = std::pair<std::string, llvm::MemoryBuffer *>;
+
+  /// Create a ASTUnit. Gets ownership of the passed CompilerInvocation.
+  static std::unique_ptr<ASTUnit>
+  create(std::shared_ptr<CompilerInvocation> CI,
+         IntrusiveRefCntPtr<DiagnosticsEngine> Diags, bool CaptureDiagnostics,
+         bool UserFilesAreVolatile);
+
+  enum WhatToLoad {
+    /// Load options and the preprocessor state.
+    LoadPreprocessorOnly,
+
+    /// Load the AST, but do not restore Sema state.
+    LoadASTOnly,
+
+    /// Load everything, including Sema.
+    LoadEverything
+  };
+
+  /// Create a ASTUnit from an AST file.
+  ///
+  /// \param Filename - The AST file to load.
+  ///
+  /// \param PCHContainerRdr - The PCHContainerOperations to use for loading and
+  /// creating modules.
+  /// \param Diags - The diagnostics engine to use for reporting errors; its
+  /// lifetime is expected to extend past that of the returned ASTUnit.
+  ///
+  /// \returns - The initialized ASTUnit or null if the AST failed to load.
+  static std::unique_ptr<ASTUnit> LoadFromASTFile(
+      const std::string &Filename, const PCHContainerReader &PCHContainerRdr,
+      WhatToLoad ToLoad, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+      const FileSystemOptions &FileSystemOpts, bool UseDebugInfo = false,
+      bool OnlyLocalDecls = false, ArrayRef<RemappedFile> RemappedFiles = None,
+      bool CaptureDiagnostics = false, bool AllowPCHWithCompilerErrors = false,
+      bool UserFilesAreVolatile = false);
+
+private:
+  /// Helper function for \c LoadFromCompilerInvocation() and
+  /// \c LoadFromCommandLine(), which loads an AST from a compiler invocation.
+  ///
+  /// \param PrecompilePreambleAfterNParses After how many parses the preamble
+  /// of this translation unit should be precompiled, to improve the performance
+  /// of reparsing. Set to zero to disable preambles.
+  ///
+  /// \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<llvm::vfs::FileSystem> VFS);
+
+public:
+  /// Create an ASTUnit from a source file, via a CompilerInvocation
+  /// object, by invoking the optionally provided ASTFrontendAction.
+  ///
+  /// \param CI - The compiler invocation to use; it must have exactly one input
+  /// source file. The ASTUnit takes ownership of the CompilerInvocation object.
+  ///
+  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
+  /// creating modules.
+  ///
+  /// \param Diags - The diagnostics engine to use for reporting errors; its
+  /// lifetime is expected to extend past that of the returned ASTUnit.
+  ///
+  /// \param Action - The ASTFrontendAction to invoke. Its ownership is not
+  /// transferred.
+  ///
+  /// \param Unit - optionally an already created ASTUnit. Its ownership is not
+  /// transferred.
+  ///
+  /// \param Persistent - if true the returned ASTUnit will be complete.
+  /// false means the caller is only interested in getting info through the
+  /// provided \see Action.
+  ///
+  /// \param ErrAST - If non-null and parsing failed without any AST to return
+  /// (e.g. because the PCH could not be loaded), this accepts the ASTUnit
+  /// mainly to allow the caller to see the diagnostics.
+  /// This will only receive an ASTUnit if a new one was created. If an already
+  /// created ASTUnit was passed in \p Unit then the caller can check that.
+  ///
+  static ASTUnit *LoadFromCompilerInvocationAction(
+      std::shared_ptr<CompilerInvocation> CI,
+      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+      IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+      FrontendAction *Action = nullptr, ASTUnit *Unit = nullptr,
+      bool Persistent = true, StringRef ResourceFilesPath = StringRef(),
+      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
+      unsigned PrecompilePreambleAfterNParses = 0,
+      bool CacheCodeCompletionResults = false,
+      bool IncludeBriefCommentsInCodeCompletion = false,
+      bool UserFilesAreVolatile = false,
+      std::unique_ptr<ASTUnit> *ErrAST = nullptr);
+
+  /// LoadFromCompilerInvocation - Create an ASTUnit from a source file, via a
+  /// CompilerInvocation object.
+  ///
+  /// \param CI - The compiler invocation to use; it must have exactly one input
+  /// source file. The ASTUnit takes ownership of the CompilerInvocation object.
+  ///
+  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
+  /// creating modules.
+  ///
+  /// \param Diags - The diagnostics engine to use for reporting errors; its
+  /// lifetime is expected to extend past that of the returned ASTUnit.
+  //
+  // FIXME: Move OnlyLocalDecls, UseBumpAllocator to setters on the ASTUnit, we
+  // shouldn't need to specify them at construction time.
+  static std::unique_ptr<ASTUnit> LoadFromCompilerInvocation(
+      std::shared_ptr<CompilerInvocation> CI,
+      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+      IntrusiveRefCntPtr<DiagnosticsEngine> Diags, FileManager *FileMgr,
+      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
+      unsigned PrecompilePreambleAfterNParses = 0,
+      TranslationUnitKind TUKind = TU_Complete,
+      bool CacheCodeCompletionResults = false,
+      bool IncludeBriefCommentsInCodeCompletion = false,
+      bool UserFilesAreVolatile = false);
+
+  /// LoadFromCommandLine - Create an ASTUnit from a vector of command line
+  /// arguments, which must specify exactly one source file.
+  ///
+  /// \param ArgBegin - The beginning of the argument vector.
+  ///
+  /// \param ArgEnd - The end of the argument vector.
+  ///
+  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
+  /// creating modules.
+  ///
+  /// \param Diags - The diagnostics engine to use for reporting errors; its
+  /// lifetime is expected to extend past that of the returned ASTUnit.
+  ///
+  /// \param ResourceFilesPath - The path to the compiler resource files.
+  ///
+  /// \param ModuleFormat - If provided, uses the specific module format.
+  ///
+  /// \param ErrAST - If non-null and parsing failed without any AST to return
+  /// (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 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.
+  static ASTUnit *LoadFromCommandLine(
+      const char **ArgBegin, const char **ArgEnd,
+      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+      IntrusiveRefCntPtr<DiagnosticsEngine> Diags, StringRef ResourceFilesPath,
+      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
+      ArrayRef<RemappedFile> RemappedFiles = None,
+      bool RemappedFilesKeepOriginalName = true,
+      unsigned PrecompilePreambleAfterNParses = 0,
+      TranslationUnitKind TUKind = TU_Complete,
+      bool CacheCodeCompletionResults = false,
+      bool IncludeBriefCommentsInCodeCompletion = false,
+      bool AllowPCHWithCompilerErrors = false,
+      SkipFunctionBodiesScope SkipFunctionBodies =
+          SkipFunctionBodiesScope::None,
+      bool SingleFileParse = false, bool UserFilesAreVolatile = false,
+      bool ForSerialization = false,
+      llvm::Optional<StringRef> ModuleFormat = llvm::None,
+      std::unique_ptr<ASTUnit> *ErrAST = 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 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<llvm::vfs::FileSystem> VFS = nullptr);
+
+  /// Free data that will be re-generated on the next parse.
+  ///
+  /// Preamble-related data is not affected.
+  void ResetForParse();
+
+  /// Perform code completion at the given file, line, and
+  /// column within this translation unit.
+  ///
+  /// \param File The file in which code completion will occur.
+  ///
+  /// \param Line The line at which code completion will occur.
+  ///
+  /// \param Column The column at which code completion will occur.
+  ///
+  /// \param IncludeMacros Whether to include macros in the code-completion
+  /// results.
+  ///
+  /// \param IncludeCodePatterns Whether to include code patterns (such as a
+  /// for loop) in the code-completion results.
+  ///
+  /// \param IncludeBriefComments Whether to include brief documentation within
+  /// the set of code completions returned.
+  ///
+  /// FIXME: The Diag, LangOpts, SourceMgr, FileMgr, StoredDiagnostics, and
+  /// OwnedBuffers parameters are all disgusting hacks. They will go away.
+  void CodeComplete(StringRef File, unsigned Line, unsigned Column,
+                    ArrayRef<RemappedFile> RemappedFiles, bool IncludeMacros,
+                    bool IncludeCodePatterns, bool IncludeBriefComments,
+                    CodeCompleteConsumer &Consumer,
+                    std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+                    DiagnosticsEngine &Diag, LangOptions &LangOpts,
+                    SourceManager &SourceMgr, FileManager &FileMgr,
+                    SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
+                    SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers);
+
+  /// Save this translation unit to a file with the given name.
+  ///
+  /// \returns true if there was a file error or false if the save was
+  /// successful.
+  bool Save(StringRef File);
+
+  /// Serialize this translation unit with the given output stream.
+  ///
+  /// \returns True if an error occurred, false otherwise.
+  bool serialize(raw_ostream &OS);
+};
+
+} // namespace clang
+
+#endif // LLVM_CLANG_FRONTEND_ASTUNIT_H