Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- 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/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 <optional>

#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 InMemoryModuleCache;

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 };

/// \brief Enumerates the available kinds for capturing diagnostics.

enum class CaptureDiagsKind { None, All, AllWithoutNonErrorsFromIncludes };

/// 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<InMemoryModuleCache> ModuleCache;

  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.

  CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None;

  /// 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, std::unique_ptr<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 PreambleRebuildCountdown = 0;

  /// Counter indicating how often the preamble was build in total.

  unsigned PreambleCounter = 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.

  std::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, CaptureDiagsKind 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 = std::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 std::recursive_mutex 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()));

  }

  unsigned getPreambleCounterForTests() const { return PreambleCounter; }

  // 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,

         CaptureDiagsKind 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,

                  CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,

                  bool AllowASTWithCompilerErrors = false,

                  bool UserFilesAreVolatile = false,

                  IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS =

                      llvm::vfs::getRealFileSystem());

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,

      CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,

      unsigned PrecompilePreambleAfterNParses = 0,

      bool CacheCodeCompletionResults = 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,

      CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,

      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,

      CaptureDiagsKind CaptureDiagnostics = CaptureDiagsKind::None,

      ArrayRef<RemappedFile> RemappedFiles = std::nullopt,

      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,

      bool RetainExcludedConditionalBlocks = false,

      std::optional<StringRef> ModuleFormat = std::nullopt,

      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 = std::nullopt,

               IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = nullptr);

  /// Free data that will be re-generated on the next parse.

  ///

  /// Preamble-related data is not affected.