include/clang/Lex/PreprocessingRecord.h - third_party/swift-clang - Git at Google

 //===--- PreprocessingRecord.h - Record of Preprocessing --------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file defines the PreprocessingRecord class, which maintains a record
 //  of what occurred during preprocessing.
 //
 //===----------------------------------------------------------------------===//
 #ifndef LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
 #define LLVM_CLANG_LEX_PREPROCESSINGRECORD_H

 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Lex/PPCallbacks.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Compiler.h"
 #include <vector>

 namespace clang {
   class IdentifierInfo;
   class MacroInfo;
   class PreprocessingRecord;
 }

 /// \brief Allocates memory within a Clang preprocessing record.
 void *operator new(size_t bytes, clang::PreprocessingRecord &PR,
                    unsigned alignment = 8) LLVM_NOEXCEPT;

 /// \brief Frees memory allocated in a Clang preprocessing record.
 void operator delete(void *ptr, clang::PreprocessingRecord &PR,
                      unsigned) LLVM_NOEXCEPT;

 namespace clang {
   class MacroDefinitionRecord;
   class FileEntry;

   /// \brief Base class that describes a preprocessed entity, which may be a
   /// preprocessor directive or macro expansion.
   class PreprocessedEntity {
   public:
     /// \brief The kind of preprocessed entity an object describes.
     enum EntityKind {
       /// \brief Indicates a problem trying to load the preprocessed entity.
       InvalidKind,

       /// \brief A macro expansion.
       MacroExpansionKind,

       /// \defgroup Preprocessing directives
       /// @{

       /// \brief A macro definition.
       MacroDefinitionKind,

       /// \brief An inclusion directive, such as \c \#include, \c
       /// \#import, or \c \#include_next.
       InclusionDirectiveKind,

       /// @}

       FirstPreprocessingDirective = MacroDefinitionKind,
       LastPreprocessingDirective = InclusionDirectiveKind
     };

   private:
     /// \brief The kind of preprocessed entity that this object describes.
     EntityKind Kind;

     /// \brief The source range that covers this preprocessed entity.
     SourceRange Range;

   protected:
     PreprocessedEntity(EntityKind Kind, SourceRange Range)
       : Kind(Kind), Range(Range) { }

     friend class PreprocessingRecord;

   public:
     /// \brief Retrieve the kind of preprocessed entity stored in this object.
     EntityKind getKind() const { return Kind; }

     /// \brief Retrieve the source range that covers this entire preprocessed
     /// entity.
     SourceRange getSourceRange() const LLVM_READONLY { return Range; }

     /// \brief Returns true if there was a problem loading the preprocessed
     /// entity.
     bool isInvalid() const { return Kind == InvalidKind; }

     // Only allow allocation of preprocessed entities using the allocator
     // in PreprocessingRecord or by doing a placement new.
     void *operator new(size_t bytes, PreprocessingRecord &PR,
                        unsigned alignment = 8) LLVM_NOEXCEPT {
       return ::operator new(bytes, PR, alignment);
     }

     void *operator new(size_t bytes, void *mem) LLVM_NOEXCEPT { return mem; }

     void operator delete(void *ptr, PreprocessingRecord &PR,
                          unsigned alignment) LLVM_NOEXCEPT {
       return ::operator delete(ptr, PR, alignment);
     }

     void operator delete(void *, std::size_t) LLVM_NOEXCEPT {}
     void operator delete(void *, void *) LLVM_NOEXCEPT {}

   private:
     // Make vanilla 'new' and 'delete' illegal for preprocessed entities.
     void *operator new(size_t bytes) LLVM_NOEXCEPT;
     void operator delete(void *data) LLVM_NOEXCEPT;
   };

   /// \brief Records the presence of a preprocessor directive.
   class PreprocessingDirective : public PreprocessedEntity {
   public:
     PreprocessingDirective(EntityKind Kind, SourceRange Range)
       : PreprocessedEntity(Kind, Range) { }

     // Implement isa/cast/dyncast/etc.
     static bool classof(const PreprocessedEntity *PD) {
       return PD->getKind() >= FirstPreprocessingDirective &&
              PD->getKind() <= LastPreprocessingDirective;
     }
   };

   /// \brief Record the location of a macro definition.
   class MacroDefinitionRecord : public PreprocessingDirective {
     /// \brief The name of the macro being defined.
     const IdentifierInfo *Name;

   public:
     explicit MacroDefinitionRecord(const IdentifierInfo *Name,
                                    SourceRange Range)
         : PreprocessingDirective(MacroDefinitionKind, Range), Name(Name) {}

     /// \brief Retrieve the name of the macro being defined.
     const IdentifierInfo *getName() const { return Name; }

     /// \brief Retrieve the location of the macro name in the definition.
     SourceLocation getLocation() const { return getSourceRange().getBegin(); }

     // Implement isa/cast/dyncast/etc.
     static bool classof(const PreprocessedEntity *PE) {
       return PE->getKind() == MacroDefinitionKind;
     }
   };

   /// \brief Records the location of a macro expansion.
   class MacroExpansion : public PreprocessedEntity {
     /// \brief The definition of this macro or the name of the macro if it is
     /// a builtin macro.
     llvm::PointerUnion<IdentifierInfo *, MacroDefinitionRecord *> NameOrDef;

   public:
     MacroExpansion(IdentifierInfo *BuiltinName, SourceRange Range)
         : PreprocessedEntity(MacroExpansionKind, Range),
           NameOrDef(BuiltinName) {}

     MacroExpansion(MacroDefinitionRecord *Definition, SourceRange Range)
         : PreprocessedEntity(MacroExpansionKind, Range), NameOrDef(Definition) {
     }

     /// \brief True if it is a builtin macro.
     bool isBuiltinMacro() const { return NameOrDef.is<IdentifierInfo *>(); }

     /// \brief The name of the macro being expanded.
     const IdentifierInfo *getName() const {
       if (MacroDefinitionRecord *Def = getDefinition())
         return Def->getName();
       return NameOrDef.get<IdentifierInfo *>();
     }

     /// \brief The definition of the macro being expanded. May return null if
     /// this is a builtin macro.
     MacroDefinitionRecord *getDefinition() const {
       return NameOrDef.dyn_cast<MacroDefinitionRecord *>();
     }

     // Implement isa/cast/dyncast/etc.
     static bool classof(const PreprocessedEntity *PE) {
       return PE->getKind() == MacroExpansionKind;
     }
   };

   /// \brief Record the location of an inclusion directive, such as an
   /// \c \#include or \c \#import statement.
   class InclusionDirective : public PreprocessingDirective {
   public:
     /// \brief The kind of inclusion directives known to the
     /// preprocessor.
     enum InclusionKind {
       /// \brief An \c \#include directive.
       Include,
       /// \brief An Objective-C \c \#import directive.
       Import,
       /// \brief A GNU \c \#include_next directive.
       IncludeNext,
       /// \brief A Clang \c \#__include_macros directive.
       IncludeMacros
     };

   private:
     /// \brief The name of the file that was included, as written in
     /// the source.
     StringRef FileName;

     /// \brief Whether the file name was in quotation marks; otherwise, it was
     /// in angle brackets.
     unsigned InQuotes : 1;

     /// \brief The kind of inclusion directive we have.
     ///
     /// This is a value of type InclusionKind.
     unsigned Kind : 2;

     /// \brief Whether the inclusion directive was automatically turned into
     /// a module import.
     unsigned ImportedModule : 1;

     /// \brief The file that was included.
     const FileEntry *File;

   public:
     InclusionDirective(PreprocessingRecord &PPRec,
                        InclusionKind Kind, StringRef FileName,
                        bool InQuotes, bool ImportedModule,
                        const FileEntry *File, SourceRange Range);

     /// \brief Determine what kind of inclusion directive this is.
     InclusionKind getKind() const { return static_cast<InclusionKind>(Kind); }

     /// \brief Retrieve the included file name as it was written in the source.
     StringRef getFileName() const { return FileName; }

     /// \brief Determine whether the included file name was written in quotes;
     /// otherwise, it was written in angle brackets.
     bool wasInQuotes() const { return InQuotes; }

     /// \brief Determine whether the inclusion directive was automatically
     /// turned into a module import.
     bool importedModule() const { return ImportedModule; }

     /// \brief Retrieve the file entry for the actual file that was included
     /// by this directive.
     const FileEntry *getFile() const { return File; }

     // Implement isa/cast/dyncast/etc.
     static bool classof(const PreprocessedEntity *PE) {
       return PE->getKind() == InclusionDirectiveKind;
     }
   };

   /// \brief An abstract class that should be subclassed by any external source
   /// of preprocessing record entries.
   class ExternalPreprocessingRecordSource {
   public:
     virtual ~ExternalPreprocessingRecordSource();

     /// \brief Read a preallocated preprocessed entity from the external source.
     ///
     /// \returns null if an error occurred that prevented the preprocessed
     /// entity from being loaded.
     virtual PreprocessedEntity *ReadPreprocessedEntity(unsigned Index) = 0;

     /// \brief Returns a pair of [Begin, End) indices of preallocated
     /// preprocessed entities that \p Range encompasses.
     virtual std::pair<unsigned, unsigned>
         findPreprocessedEntitiesInRange(SourceRange Range) = 0;

     /// \brief Optionally returns true or false if the preallocated preprocessed
     /// entity with index \p Index came from file \p FID.
     virtual Optional<bool> isPreprocessedEntityInFileID(unsigned Index,
                                                         FileID FID) {
       return None;
     }
   };

   /// \brief A record of the steps taken while preprocessing a source file,
   /// including the various preprocessing directives processed, macros
   /// expanded, etc.
   class PreprocessingRecord : public PPCallbacks {
     SourceManager &SourceMgr;

     /// \brief Allocator used to store preprocessing objects.
     llvm::BumpPtrAllocator BumpAlloc;

     /// \brief The set of preprocessed entities in this record, in order they
     /// were seen.
     std::vector<PreprocessedEntity *> PreprocessedEntities;

     /// \brief The set of preprocessed entities in this record that have been
     /// loaded from external sources.
     ///
     /// The entries in this vector are loaded lazily from the external source,
     /// and are referenced by the iterator using negative indices.
     std::vector<PreprocessedEntity *> LoadedPreprocessedEntities;

     /// \brief The set of ranges that were skipped by the preprocessor,
     std::vector<SourceRange> SkippedRanges;

     /// \brief Global (loaded or local) ID for a preprocessed entity.
     /// Negative values are used to indicate preprocessed entities
     /// loaded from the external source while non-negative values are used to
     /// indicate preprocessed entities introduced by the current preprocessor.
     /// Value -1 corresponds to element 0 in the loaded entities vector,
     /// value -2 corresponds to element 1 in the loaded entities vector, etc.
     /// Value 0 is an invalid value, the index to local entities is 1-based,
     /// value 1 corresponds to element 0 in the local entities vector,
     /// value 2 corresponds to element 1 in the local entities vector, etc.
     class PPEntityID {
       int ID;
       explicit PPEntityID(int ID) : ID(ID) {}
       friend class PreprocessingRecord;
     public:
       PPEntityID() : ID(0) {}
     };

     static PPEntityID getPPEntityID(unsigned Index, bool isLoaded) {
       return isLoaded ? PPEntityID(-int(Index)-1) : PPEntityID(Index+1);
     }

     /// \brief Mapping from MacroInfo structures to their definitions.
     llvm::DenseMap<const MacroInfo *, MacroDefinitionRecord *> MacroDefinitions;

     /// \brief External source of preprocessed entities.
     ExternalPreprocessingRecordSource *ExternalSource;

     /// \brief Retrieve the preprocessed entity at the given ID.
     PreprocessedEntity *getPreprocessedEntity(PPEntityID PPID);

     /// \brief Retrieve the loaded preprocessed entity at the given index.
     PreprocessedEntity *getLoadedPreprocessedEntity(unsigned Index);

     /// \brief Determine the number of preprocessed entities that were
     /// loaded (or can be loaded) from an external source.
     unsigned getNumLoadedPreprocessedEntities() const {
       return LoadedPreprocessedEntities.size();
     }

     /// \brief Returns a pair of [Begin, End) indices of local preprocessed
     /// entities that \p Range encompasses.
     std::pair<unsigned, unsigned>
       findLocalPreprocessedEntitiesInRange(SourceRange Range) const;
     unsigned findBeginLocalPreprocessedEntity(SourceLocation Loc) const;
     unsigned findEndLocalPreprocessedEntity(SourceLocation Loc) const;

     /// \brief Allocate space for a new set of loaded preprocessed entities.
     ///
     /// \returns The index into the set of loaded preprocessed entities, which
     /// corresponds to the first newly-allocated entity.
     unsigned allocateLoadedEntities(unsigned NumEntities);

     /// \brief Register a new macro definition.
     void RegisterMacroDefinition(MacroInfo *Macro, MacroDefinitionRecord *Def);

   public:
     /// \brief Construct a new preprocessing record.
     explicit PreprocessingRecord(SourceManager &SM);

     /// \brief Allocate memory in the preprocessing record.
     void *Allocate(unsigned Size, unsigned Align = 8) {
       return BumpAlloc.Allocate(Size, Align);
     }

     /// \brief Deallocate memory in the preprocessing record.
     void Deallocate(void *Ptr) { }

     size_t getTotalMemory() const;

     SourceManager &getSourceManager() const { return SourceMgr; }

     /// Iteration over the preprocessed entities.
     ///
     /// In a complete iteration, the iterator walks the range [-M, N),
     /// where negative values are used to indicate preprocessed entities
     /// loaded from the external source while non-negative values are used to
     /// indicate preprocessed entities introduced by the current preprocessor.
     /// However, to provide iteration in source order (for, e.g., chained
     /// precompiled headers), dereferencing the iterator flips the negative
     /// values (corresponding to loaded entities), so that position -M
     /// corresponds to element 0 in the loaded entities vector, position -M+1
     /// corresponds to element 1 in the loaded entities vector, etc. This
     /// gives us a reasonably efficient, source-order walk.
     ///
     /// We define this as a wrapping iterator around an int. The
     /// iterator_adaptor_base class forwards the iterator methods to basic
     /// integer arithmetic.
     class iterator : public llvm::iterator_adaptor_base<
                          iterator, int, std::random_access_iterator_tag,
                          PreprocessedEntity *, int, PreprocessedEntity *,
                          PreprocessedEntity *> {
       PreprocessingRecord *Self;

       iterator(PreprocessingRecord *Self, int Position)
           : iterator::iterator_adaptor_base(Position), Self(Self) {}
       friend class PreprocessingRecord;

     public:
       iterator() : iterator(nullptr, 0) {}

       PreprocessedEntity *operator*() const {
         bool isLoaded = this->I < 0;
         unsigned Index = isLoaded ?
             Self->LoadedPreprocessedEntities.size() + this->I : this->I;
         PPEntityID ID = Self->getPPEntityID(Index, isLoaded);
         return Self->getPreprocessedEntity(ID);
       }
       PreprocessedEntity *operator->() const { return **this; }
     };

     /// \brief Begin iterator for all preprocessed entities.
     iterator begin() {
       return iterator(this, -(int)LoadedPreprocessedEntities.size());
     }

     /// \brief End iterator for all preprocessed entities.
     iterator end() {
       return iterator(this, PreprocessedEntities.size());
     }

     /// \brief Begin iterator for local, non-loaded, preprocessed entities.
     iterator local_begin() {
       return iterator(this, 0);
     }

     /// \brief End iterator for local, non-loaded, preprocessed entities.
     iterator local_end() {
       return iterator(this, PreprocessedEntities.size());
     }

     /// \brief iterator range for the given range of loaded
     /// preprocessed entities.
     llvm::iterator_range<iterator> getIteratorsForLoadedRange(unsigned start,
                                                               unsigned count) {
       unsigned end = start + count;
       assert(end <= LoadedPreprocessedEntities.size());
       return llvm::make_range(
           iterator(this, int(start) - LoadedPreprocessedEntities.size()),
           iterator(this, int(end) - LoadedPreprocessedEntities.size()));
     }

     /// \brief Returns a range of preprocessed entities that source range \p R
     /// encompasses.
     ///
     /// \param R the range to look for preprocessed entities.
     ///
     llvm::iterator_range<iterator>
     getPreprocessedEntitiesInRange(SourceRange R);

     /// \brief Returns true if the preprocessed entity that \p PPEI iterator
     /// points to is coming from the file \p FID.
     ///
     /// Can be used to avoid implicit deserializations of preallocated
     /// preprocessed entities if we only care about entities of a specific file
     /// and not from files \#included in the range given at
     /// \see getPreprocessedEntitiesInRange.
     bool isEntityInFileID(iterator PPEI, FileID FID);

     /// \brief Add a new preprocessed entity to this record.
     PPEntityID addPreprocessedEntity(PreprocessedEntity *Entity);

     /// \brief Set the external source for preprocessed entities.
     void SetExternalSource(ExternalPreprocessingRecordSource &Source);

     /// \brief Retrieve the external source for preprocessed entities.
     ExternalPreprocessingRecordSource *getExternalSource() const {
       return ExternalSource;
     }

     /// \brief Retrieve the macro definition that corresponds to the given
     /// \c MacroInfo.
     MacroDefinitionRecord *findMacroDefinition(const MacroInfo *MI);

     /// \brief Retrieve all ranges that got skipped while preprocessing.
     const std::vector<SourceRange> &getSkippedRanges() const {
       return SkippedRanges;
     }

   private:
     void MacroExpands(const Token &Id, const MacroDefinition &MD,
                       SourceRange Range, const MacroArgs *Args) override;
     void MacroDefined(const Token &Id, const MacroDirective *MD) override;
     void MacroUndefined(const Token &Id, const MacroDefinition &MD) override;
     void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
                             StringRef FileName, bool IsAngled,
                             CharSourceRange FilenameRange,
                             const FileEntry *File, StringRef SearchPath,
                             StringRef RelativePath,
                             const Module *Imported) override;
     void Ifdef(SourceLocation Loc, const Token &MacroNameTok,
                const MacroDefinition &MD) override;
     void Ifndef(SourceLocation Loc, const Token &MacroNameTok,
                 const MacroDefinition &MD) override;
     /// \brief Hook called whenever the 'defined' operator is seen.
     void Defined(const Token &MacroNameTok, const MacroDefinition &MD,
                  SourceRange Range) override;

     void SourceRangeSkipped(SourceRange Range) override;

     void addMacroExpansion(const Token &Id, const MacroInfo *MI,
                            SourceRange Range);

     /// \brief Cached result of the last \see getPreprocessedEntitiesInRange
     /// query.
     struct {
       SourceRange Range;
       std::pair<int, int> Result;
     } CachedRangeQuery;

     std::pair<int, int> getPreprocessedEntitiesInRangeSlow(SourceRange R);

     friend class ASTReader;
     friend class ASTWriter;
   };
 } // end namespace clang

 inline void *operator new(size_t bytes, clang::PreprocessingRecord &PR,
                           unsigned alignment) LLVM_NOEXCEPT {
   return PR.Allocate(bytes, alignment);
 }

 inline void operator delete(void *ptr, clang::PreprocessingRecord &PR,
                             unsigned) LLVM_NOEXCEPT {
   PR.Deallocate(ptr);
 }

 #endif // LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
	//===--- PreprocessingRecord.h - Record of Preprocessing --------- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file defines the PreprocessingRecord class, which maintains a record
	// of what occurred during preprocessing.
	//
	//===----------------------------------------------------------------------===//
	#ifndef LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
	#define LLVM_CLANG_LEX_PREPROCESSINGRECORD_H

	#include "clang/Basic/IdentifierTable.h"
	#include "clang/Basic/SourceLocation.h"
	#include "clang/Lex/PPCallbacks.h"
	#include "llvm/ADT/DenseMap.h"
	#include "llvm/ADT/Optional.h"
	#include "llvm/ADT/iterator.h"
	#include "llvm/Support/Allocator.h"
	#include "llvm/Support/Compiler.h"
	#include <vector>

	namespace clang {
	class IdentifierInfo;
	class MacroInfo;
	class PreprocessingRecord;
	}

	/// \brief Allocates memory within a Clang preprocessing record.
	void *operator new(size_t bytes, clang::PreprocessingRecord &PR,
	unsigned alignment = 8) LLVM_NOEXCEPT;

	/// \brief Frees memory allocated in a Clang preprocessing record.
	void operator delete(void *ptr, clang::PreprocessingRecord &PR,
	unsigned) LLVM_NOEXCEPT;

	namespace clang {
	class MacroDefinitionRecord;
	class FileEntry;

	/// \brief Base class that describes a preprocessed entity, which may be a
	/// preprocessor directive or macro expansion.
	class PreprocessedEntity {
	public:
	/// \brief The kind of preprocessed entity an object describes.
	enum EntityKind {
	/// \brief Indicates a problem trying to load the preprocessed entity.
	InvalidKind,

	/// \brief A macro expansion.
	MacroExpansionKind,

	/// \defgroup Preprocessing directives
	/// @{

	/// \brief A macro definition.
	MacroDefinitionKind,

	/// \brief An inclusion directive, such as \c \#include, \c
	/// \#import, or \c \#include_next.
	InclusionDirectiveKind,

	/// @}

	FirstPreprocessingDirective = MacroDefinitionKind,
	LastPreprocessingDirective = InclusionDirectiveKind
	};

	private:
	/// \brief The kind of preprocessed entity that this object describes.
	EntityKind Kind;

	/// \brief The source range that covers this preprocessed entity.
	SourceRange Range;

	protected:
	PreprocessedEntity(EntityKind Kind, SourceRange Range)
	: Kind(Kind), Range(Range) { }

	friend class PreprocessingRecord;

	public:
	/// \brief Retrieve the kind of preprocessed entity stored in this object.
	EntityKind getKind() const { return Kind; }

	/// \brief Retrieve the source range that covers this entire preprocessed
	/// entity.
	SourceRange getSourceRange() const LLVM_READONLY { return Range; }

	/// \brief Returns true if there was a problem loading the preprocessed
	/// entity.
	bool isInvalid() const { return Kind == InvalidKind; }

	// Only allow allocation of preprocessed entities using the allocator
	// in PreprocessingRecord or by doing a placement new.
	void *operator new(size_t bytes, PreprocessingRecord &PR,
	unsigned alignment = 8) LLVM_NOEXCEPT {
	return ::operator new(bytes, PR, alignment);
	}

	void operator new(size_t bytes, void mem) LLVM_NOEXCEPT { return mem; }

	void operator delete(void *ptr, PreprocessingRecord &PR,
	unsigned alignment) LLVM_NOEXCEPT {
	return ::operator delete(ptr, PR, alignment);
	}

	void operator delete(void *, std::size_t) LLVM_NOEXCEPT {}
	void operator delete(void , void ) LLVM_NOEXCEPT {}

	private:
	// Make vanilla 'new' and 'delete' illegal for preprocessed entities.
	void *operator new(size_t bytes) LLVM_NOEXCEPT;
	void operator delete(void *data) LLVM_NOEXCEPT;
	};

	/// \brief Records the presence of a preprocessor directive.
	class PreprocessingDirective : public PreprocessedEntity {
	public:
	PreprocessingDirective(EntityKind Kind, SourceRange Range)
	: PreprocessedEntity(Kind, Range) { }

	// Implement isa/cast/dyncast/etc.
	static bool classof(const PreprocessedEntity *PD) {
	return PD->getKind() >= FirstPreprocessingDirective &&
	PD->getKind() <= LastPreprocessingDirective;
	}
	};

	/// \brief Record the location of a macro definition.
	class MacroDefinitionRecord : public PreprocessingDirective {
	/// \brief The name of the macro being defined.
	const IdentifierInfo *Name;

	public:
	explicit MacroDefinitionRecord(const IdentifierInfo *Name,
	SourceRange Range)
	: PreprocessingDirective(MacroDefinitionKind, Range), Name(Name) {}

	/// \brief Retrieve the name of the macro being defined.
	const IdentifierInfo *getName() const { return Name; }

	/// \brief Retrieve the location of the macro name in the definition.
	SourceLocation getLocation() const { return getSourceRange().getBegin(); }

	// Implement isa/cast/dyncast/etc.
	static bool classof(const PreprocessedEntity *PE) {
	return PE->getKind() == MacroDefinitionKind;
	}
	};

	/// \brief Records the location of a macro expansion.
	class MacroExpansion : public PreprocessedEntity {
	/// \brief The definition of this macro or the name of the macro if it is
	/// a builtin macro.
	llvm::PointerUnion<IdentifierInfo , MacroDefinitionRecord > NameOrDef;

	public:
	MacroExpansion(IdentifierInfo *BuiltinName, SourceRange Range)
	: PreprocessedEntity(MacroExpansionKind, Range),
	NameOrDef(BuiltinName) {}

	MacroExpansion(MacroDefinitionRecord *Definition, SourceRange Range)
	: PreprocessedEntity(MacroExpansionKind, Range), NameOrDef(Definition) {
	}

	/// \brief True if it is a builtin macro.
	bool isBuiltinMacro() const { return NameOrDef.is<IdentifierInfo *>(); }

	/// \brief The name of the macro being expanded.
	const IdentifierInfo *getName() const {
	if (MacroDefinitionRecord *Def = getDefinition())
	return Def->getName();
	return NameOrDef.get<IdentifierInfo *>();
	}

	/// \brief The definition of the macro being expanded. May return null if
	/// this is a builtin macro.
	MacroDefinitionRecord *getDefinition() const {
	return NameOrDef.dyn_cast<MacroDefinitionRecord *>();
	}

	// Implement isa/cast/dyncast/etc.
	static bool classof(const PreprocessedEntity *PE) {
	return PE->getKind() == MacroExpansionKind;
	}
	};

	/// \brief Record the location of an inclusion directive, such as an
	/// \c \#include or \c \#import statement.
	class InclusionDirective : public PreprocessingDirective {
	public:
	/// \brief The kind of inclusion directives known to the
	/// preprocessor.
	enum InclusionKind {
	/// \brief An \c \#include directive.
	Include,
	/// \brief An Objective-C \c \#import directive.
	Import,
	/// \brief A GNU \c \#include_next directive.
	IncludeNext,
	/// \brief A Clang \c \#__include_macros directive.
	IncludeMacros
	};

	private:
	/// \brief The name of the file that was included, as written in
	/// the source.
	StringRef FileName;

	/// \brief Whether the file name was in quotation marks; otherwise, it was
	/// in angle brackets.
	unsigned InQuotes : 1;

	/// \brief The kind of inclusion directive we have.
	///
	/// This is a value of type InclusionKind.
	unsigned Kind : 2;

	/// \brief Whether the inclusion directive was automatically turned into
	/// a module import.
	unsigned ImportedModule : 1;

	/// \brief The file that was included.
	const FileEntry *File;

	public:
	InclusionDirective(PreprocessingRecord &PPRec,
	InclusionKind Kind, StringRef FileName,
	bool InQuotes, bool ImportedModule,
	const FileEntry *File, SourceRange Range);

	/// \brief Determine what kind of inclusion directive this is.
	InclusionKind getKind() const { return static_cast<InclusionKind>(Kind); }

	/// \brief Retrieve the included file name as it was written in the source.
	StringRef getFileName() const { return FileName; }

	/// \brief Determine whether the included file name was written in quotes;
	/// otherwise, it was written in angle brackets.
	bool wasInQuotes() const { return InQuotes; }

	/// \brief Determine whether the inclusion directive was automatically
	/// turned into a module import.
	bool importedModule() const { return ImportedModule; }

	/// \brief Retrieve the file entry for the actual file that was included
	/// by this directive.
	const FileEntry *getFile() const { return File; }

	// Implement isa/cast/dyncast/etc.
	static bool classof(const PreprocessedEntity *PE) {
	return PE->getKind() == InclusionDirectiveKind;
	}
	};

	/// \brief An abstract class that should be subclassed by any external source
	/// of preprocessing record entries.
	class ExternalPreprocessingRecordSource {
	public:
	virtual ~ExternalPreprocessingRecordSource();

	/// \brief Read a preallocated preprocessed entity from the external source.
	///
	/// \returns null if an error occurred that prevented the preprocessed
	/// entity from being loaded.
	virtual PreprocessedEntity *ReadPreprocessedEntity(unsigned Index) = 0;

	/// \brief Returns a pair of [Begin, End) indices of preallocated
	/// preprocessed entities that \p Range encompasses.
	virtual std::pair<unsigned, unsigned>
	findPreprocessedEntitiesInRange(SourceRange Range) = 0;

	/// \brief Optionally returns true or false if the preallocated preprocessed
	/// entity with index \p Index came from file \p FID.
	virtual Optional<bool> isPreprocessedEntityInFileID(unsigned Index,
	FileID FID) {
	return None;
	}
	};

	/// \brief A record of the steps taken while preprocessing a source file,
	/// including the various preprocessing directives processed, macros
	/// expanded, etc.
	class PreprocessingRecord : public PPCallbacks {
	SourceManager &SourceMgr;

	/// \brief Allocator used to store preprocessing objects.
	llvm::BumpPtrAllocator BumpAlloc;

	/// \brief The set of preprocessed entities in this record, in order they
	/// were seen.
	std::vector<PreprocessedEntity *> PreprocessedEntities;

	/// \brief The set of preprocessed entities in this record that have been
	/// loaded from external sources.
	///
	/// The entries in this vector are loaded lazily from the external source,
	/// and are referenced by the iterator using negative indices.
	std::vector<PreprocessedEntity *> LoadedPreprocessedEntities;

	/// \brief The set of ranges that were skipped by the preprocessor,
	std::vector<SourceRange> SkippedRanges;

	/// \brief Global (loaded or local) ID for a preprocessed entity.
	/// Negative values are used to indicate preprocessed entities
	/// loaded from the external source while non-negative values are used to
	/// indicate preprocessed entities introduced by the current preprocessor.
	/// Value -1 corresponds to element 0 in the loaded entities vector,
	/// value -2 corresponds to element 1 in the loaded entities vector, etc.
	/// Value 0 is an invalid value, the index to local entities is 1-based,
	/// value 1 corresponds to element 0 in the local entities vector,
	/// value 2 corresponds to element 1 in the local entities vector, etc.
	class PPEntityID {
	int ID;
	explicit PPEntityID(int ID) : ID(ID) {}
	friend class PreprocessingRecord;
	public:
	PPEntityID() : ID(0) {}
	};

	static PPEntityID getPPEntityID(unsigned Index, bool isLoaded) {
	return isLoaded ? PPEntityID(-int(Index)-1) : PPEntityID(Index+1);
	}

	/// \brief Mapping from MacroInfo structures to their definitions.
	llvm::DenseMap<const MacroInfo , MacroDefinitionRecord > MacroDefinitions;

	/// \brief External source of preprocessed entities.
	ExternalPreprocessingRecordSource *ExternalSource;

	/// \brief Retrieve the preprocessed entity at the given ID.
	PreprocessedEntity *getPreprocessedEntity(PPEntityID PPID);

	/// \brief Retrieve the loaded preprocessed entity at the given index.
	PreprocessedEntity *getLoadedPreprocessedEntity(unsigned Index);

	/// \brief Determine the number of preprocessed entities that were
	/// loaded (or can be loaded) from an external source.
	unsigned getNumLoadedPreprocessedEntities() const {
	return LoadedPreprocessedEntities.size();
	}

	/// \brief Returns a pair of [Begin, End) indices of local preprocessed
	/// entities that \p Range encompasses.
	std::pair<unsigned, unsigned>
	findLocalPreprocessedEntitiesInRange(SourceRange Range) const;
	unsigned findBeginLocalPreprocessedEntity(SourceLocation Loc) const;
	unsigned findEndLocalPreprocessedEntity(SourceLocation Loc) const;

	/// \brief Allocate space for a new set of loaded preprocessed entities.
	///
	/// \returns The index into the set of loaded preprocessed entities, which
	/// corresponds to the first newly-allocated entity.
	unsigned allocateLoadedEntities(unsigned NumEntities);

	/// \brief Register a new macro definition.
	void RegisterMacroDefinition(MacroInfo Macro, MacroDefinitionRecord Def);

	public:
	/// \brief Construct a new preprocessing record.
	explicit PreprocessingRecord(SourceManager &SM);

	/// \brief Allocate memory in the preprocessing record.
	void *Allocate(unsigned Size, unsigned Align = 8) {
	return BumpAlloc.Allocate(Size, Align);
	}

	/// \brief Deallocate memory in the preprocessing record.
	void Deallocate(void *Ptr) { }

	size_t getTotalMemory() const;

	SourceManager &getSourceManager() const { return SourceMgr; }

	/// Iteration over the preprocessed entities.
	///
	/// In a complete iteration, the iterator walks the range [-M, N),
	/// where negative values are used to indicate preprocessed entities
	/// loaded from the external source while non-negative values are used to
	/// indicate preprocessed entities introduced by the current preprocessor.
	/// However, to provide iteration in source order (for, e.g., chained
	/// precompiled headers), dereferencing the iterator flips the negative
	/// values (corresponding to loaded entities), so that position -M
	/// corresponds to element 0 in the loaded entities vector, position -M+1
	/// corresponds to element 1 in the loaded entities vector, etc. This
	/// gives us a reasonably efficient, source-order walk.
	///
	/// We define this as a wrapping iterator around an int. The
	/// iterator_adaptor_base class forwards the iterator methods to basic
	/// integer arithmetic.
	class iterator : public llvm::iterator_adaptor_base<
	iterator, int, std::random_access_iterator_tag,
	PreprocessedEntity , int, PreprocessedEntity ,
	PreprocessedEntity *> {
	PreprocessingRecord *Self;

	iterator(PreprocessingRecord *Self, int Position)
	: iterator::iterator_adaptor_base(Position), Self(Self) {}
	friend class PreprocessingRecord;

	public:
	iterator() : iterator(nullptr, 0) {}

	PreprocessedEntity operator() const {
	bool isLoaded = this->I < 0;
	unsigned Index = isLoaded ?
	Self->LoadedPreprocessedEntities.size() + this->I : this->I;
	PPEntityID ID = Self->getPPEntityID(Index, isLoaded);
	return Self->getPreprocessedEntity(ID);
	}
	PreprocessedEntity operator->() const { return *this; }
	};

	/// \brief Begin iterator for all preprocessed entities.
	iterator begin() {
	return iterator(this, -(int)LoadedPreprocessedEntities.size());
	}

	/// \brief End iterator for all preprocessed entities.
	iterator end() {
	return iterator(this, PreprocessedEntities.size());
	}

	/// \brief Begin iterator for local, non-loaded, preprocessed entities.
	iterator local_begin() {
	return iterator(this, 0);
	}

	/// \brief End iterator for local, non-loaded, preprocessed entities.
	iterator local_end() {
	return iterator(this, PreprocessedEntities.size());
	}

	/// \brief iterator range for the given range of loaded
	/// preprocessed entities.
	llvm::iterator_range<iterator> getIteratorsForLoadedRange(unsigned start,
	unsigned count) {
	unsigned end = start + count;
	assert(end <= LoadedPreprocessedEntities.size());
	return llvm::make_range(
	iterator(this, int(start) - LoadedPreprocessedEntities.size()),
	iterator(this, int(end) - LoadedPreprocessedEntities.size()));
	}

	/// \brief Returns a range of preprocessed entities that source range \p R
	/// encompasses.
	///
	/// \param R the range to look for preprocessed entities.
	///
	llvm::iterator_range<iterator>
	getPreprocessedEntitiesInRange(SourceRange R);

	/// \brief Returns true if the preprocessed entity that \p PPEI iterator
	/// points to is coming from the file \p FID.
	///
	/// Can be used to avoid implicit deserializations of preallocated
	/// preprocessed entities if we only care about entities of a specific file
	/// and not from files \#included in the range given at
	/// \see getPreprocessedEntitiesInRange.
	bool isEntityInFileID(iterator PPEI, FileID FID);

	/// \brief Add a new preprocessed entity to this record.
	PPEntityID addPreprocessedEntity(PreprocessedEntity *Entity);

	/// \brief Set the external source for preprocessed entities.
	void SetExternalSource(ExternalPreprocessingRecordSource &Source);

	/// \brief Retrieve the external source for preprocessed entities.
	ExternalPreprocessingRecordSource *getExternalSource() const {
	return ExternalSource;
	}

	/// \brief Retrieve the macro definition that corresponds to the given
	/// \c MacroInfo.
	MacroDefinitionRecord findMacroDefinition(const MacroInfo MI);

	/// \brief Retrieve all ranges that got skipped while preprocessing.
	const std::vector<SourceRange> &getSkippedRanges() const {
	return SkippedRanges;
	}

	private:
	void MacroExpands(const Token &Id, const MacroDefinition &MD,
	SourceRange Range, const MacroArgs *Args) override;
	void MacroDefined(const Token &Id, const MacroDirective *MD) override;
	void MacroUndefined(const Token &Id, const MacroDefinition &MD) override;
	void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
	StringRef FileName, bool IsAngled,
	CharSourceRange FilenameRange,
	const FileEntry *File, StringRef SearchPath,
	StringRef RelativePath,
	const Module *Imported) override;
	void Ifdef(SourceLocation Loc, const Token &MacroNameTok,
	const MacroDefinition &MD) override;
	void Ifndef(SourceLocation Loc, const Token &MacroNameTok,
	const MacroDefinition &MD) override;
	/// \brief Hook called whenever the 'defined' operator is seen.
	void Defined(const Token &MacroNameTok, const MacroDefinition &MD,
	SourceRange Range) override;

	void SourceRangeSkipped(SourceRange Range) override;

	void addMacroExpansion(const Token &Id, const MacroInfo *MI,
	SourceRange Range);

	/// \brief Cached result of the last \see getPreprocessedEntitiesInRange
	/// query.
	struct {
	SourceRange Range;
	std::pair<int, int> Result;
	} CachedRangeQuery;

	std::pair<int, int> getPreprocessedEntitiesInRangeSlow(SourceRange R);

	friend class ASTReader;
	friend class ASTWriter;
	};
	} // end namespace clang

	inline void *operator new(size_t bytes, clang::PreprocessingRecord &PR,
	unsigned alignment) LLVM_NOEXCEPT {
	return PR.Allocate(bytes, alignment);
	}

	inline void operator delete(void *ptr, clang::PreprocessingRecord &PR,
	unsigned) LLVM_NOEXCEPT {
	PR.Deallocate(ptr);
	}

	#endif // LLVM_CLANG_LEX_PREPROCESSINGRECORD_H