include/clang/Frontend/ASTUnit.h - clang - Git at Google

 //===--- ASTUnit.h - ASTUnit utility ----------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // ASTUnit utility class.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_CLANG_FRONTEND_ASTUNIT_H
 #define LLVM_CLANG_FRONTEND_ASTUNIT_H

 #include "clang/Index/ASTLocation.h"
 #include "clang/Serialization/ASTBitCodes.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Sema/CodeCompleteConsumer.h"
 #include "clang/Lex/PreprocessingRecord.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/FileManager.h"
 #include "clang-c/Index.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/System/Path.h"
 #include "llvm/Support/Timer.h"
 #include <map>
 #include <string>
 #include <vector>
 #include <cassert>
 #include <utility>
 #include <sys/types.h>

 namespace llvm {
   class MemoryBuffer;
 }

 namespace clang {
 class ASTContext;
 class CodeCompleteConsumer;
 class CompilerInvocation;
 class Decl;
 class Diagnostic;
 class FileEntry;
 class FileManager;
 class HeaderSearch;
 class Preprocessor;
 class SourceManager;
 class TargetInfo;

 using namespace idx;

 /// \brief Utility class for loading a ASTContext from an AST file.
 ///
 class ASTUnit {
 public:
   typedef std::map<FileID, std::vector<PreprocessedEntity *> >
     PreprocessedEntitiesByFileMap;

 private:
   llvm::IntrusiveRefCntPtr<Diagnostic> Diagnostics;
   llvm::OwningPtr<FileManager>      FileMgr;
   llvm::OwningPtr<SourceManager>    SourceMgr;
   llvm::OwningPtr<HeaderSearch>     HeaderInfo;
   llvm::OwningPtr<TargetInfo>       Target;
   llvm::OwningPtr<Preprocessor>     PP;
   llvm::OwningPtr<ASTContext>       Ctx;

   /// \brief The AST consumer that received information about the translation
   /// unit as it was parsed or loaded.
   llvm::OwningPtr<ASTConsumer> Consumer;

   /// \brief The semantic analysis object used to type-check the translation
   /// unit.
   llvm::OwningPtr<Sema> TheSema;

   /// Optional owned invocation, just used to make the invocation used in
   /// LoadFromCommandLine available.
   llvm::OwningPtr<CompilerInvocation> Invocation;

   // 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;

   /// \brief Whether to capture any diagnostics produced.
   bool CaptureDiagnostics;

   /// \brief Track whether the main file was loaded from an AST or not.
   bool MainFileIsAST;

   /// \brief Whether this AST represents a complete translation unit.
   bool CompleteTranslationUnit;

   /// 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;

   /// The name of the original source file used to generate this ASTUnit.
   std::string OriginalSourceFile;

   // Critical optimization when using clang_getCursor().
   ASTLocation LastLoc;

   /// \brief The set of diagnostics produced when creating this
   /// translation unit.
   llvm::SmallVector<StoredDiagnostic, 4> StoredDiagnostics;

   /// \brief Temporary files that should be removed when the ASTUnit is
   /// destroyed.
   llvm::SmallVector<llvm::sys::Path, 4> TemporaryFiles;

   /// \brief A mapping from file IDs to the set of preprocessed entities
   /// stored in that file.
   ///
   /// FIXME: This is just an optimization hack to avoid searching through
   /// many preprocessed entities during cursor traversal in the CIndex library.
   /// Ideally, we would just be able to perform a binary search within the
   /// list of preprocessed entities.
   PreprocessedEntitiesByFileMap PreprocessedEntitiesByFile;

   /// \brief Simple hack to allow 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.
   unsigned int ConcurrencyCheckValue;
   static const unsigned int CheckLocked = 28573289;
   static const unsigned int CheckUnlocked = 9803453;

   /// \brief 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;

   /// \brief The file in which the precompiled preamble is stored.
   std::string PreambleFile;

   /// \brief The contents of the preamble that has been precompiled to
   /// \c PreambleFile.
   std::vector<char> Preamble;

   /// \brief Whether the preamble ends at the start of a new line.
   ///
   /// Used to inform the lexer as to whether it's starting at the beginning of
   /// a line after skipping the preamble.
   bool PreambleEndsAtStartOfLine;

   /// \brief The size of the source buffer that we've reserved for the main
   /// file within the precompiled preamble.
   unsigned PreambleReservedSize;

   /// \brief Keeps track of the files that were used when computing the
   /// preamble, with both their buffer size and their modification time.
   ///
   /// If any of the files have changed from one compile to the next,
   /// the preamble must be thrown away.
   llvm::StringMap<std::pair<off_t, time_t> > FilesInPreamble;

   /// \brief 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.
   llvm::MemoryBuffer *SavedMainFileBuffer;

   /// \brief When non-NULL, this is the buffer used to store the
   /// contents of the preamble when it has been padded to build the
   /// precompiled preamble.
   llvm::MemoryBuffer *PreambleBuffer;

   /// \brief The number of warnings that occurred while parsing the preamble.
   ///
   /// This value will be used to restore the state of the \c Diagnostic 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;

   /// \brief The number of diagnostics that were stored when parsing
   /// the precompiled preamble.
   ///
   /// This value is used to determine how many of the stored
   /// diagnostics should be retained when reparsing in the presence of
   /// a precompiled preamble.
   unsigned NumStoredDiagnosticsInPreamble;

   /// \brief The group of timers associated with this translation unit.
   llvm::OwningPtr<llvm::TimerGroup> TimerGroup;

   /// \brief A list of the serialization ID numbers for each of the top-level
   /// declarations parsed within the precompiled preamble.
   std::vector<serialization::DeclID> TopLevelDeclsInPreamble;

   ///
   /// \defgroup CodeCompleteCaching Code-completion caching
   ///
   /// \{
   ///

   /// \brief Whether we should be caching code-completion results.
   bool ShouldCacheCodeCompletionResults;

 public:
   /// \brief A cached code-completion result, which may be introduced in one of
   /// many different contexts.
   struct CachedCodeCompletionResult {
     /// \brief The code-completion string corresponding to this completion
     /// result.
     CodeCompletionString *Completion;

     /// \brief 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, subtract one from the completion context kind and shift 1 by that
     /// number of bits. Many completions can occur in several different
     /// contexts.
     unsigned ShowInContexts;

     /// \brief The priority given to this code-completion result.
     unsigned Priority;

     /// \brief The libclang cursor kind corresponding to this code-completion
     /// result.
     CXCursorKind Kind;

     /// \brief The availability of this code-completion result.
     CXAvailabilityKind Availability;

     /// \brief The simplified type class for a non-macro completion result.
     SimplifiedTypeClass TypeClass;

     /// \brief 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;
   };

   /// \brief Retrieve the mapping from formatted type names to unique type
   /// identifiers.
   llvm::StringMap<unsigned> &getCachedCompletionTypes() {
     return CachedCompletionTypes;
   }

 private:
   /// \brief The set of cached code-completion results.
   std::vector<CachedCodeCompletionResult> CachedCompletionResults;

   /// \brief 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;

   /// \brief The number of top-level declarations present the last time we
   /// cached code-completion results.
   ///
   /// The value is used to help detect when we should repopulate the global
   /// completion cache.
   unsigned NumTopLevelDeclsAtLastCompletionCache;

   /// \brief The number of reparses left until we'll consider updating the
   /// code-completion cache.
   ///
   /// This is meant to avoid thrashing during reparsing, by not allowing the
   /// code-completion cache to be updated on every reparse.
   unsigned CacheCodeCompletionCoolDown;

   /// \brief 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 Cache any "global" code-completion results, so that we can avoid
   /// recomputing them with each completion.
   void CacheCodeCompletionResults();

   /// \brief Clear out and deallocate
   void ClearCachedCompletionResults();

   ///
   /// \}
   ///

   /// \brief The timers we've created from the various parses, reparses, etc.
   /// involved in this translation unit.
   std::vector<llvm::Timer *> Timers;

   ASTUnit(const ASTUnit&); // DO NOT IMPLEMENT
   ASTUnit &operator=(const ASTUnit &); // DO NOT IMPLEMENT

   explicit ASTUnit(bool MainFileIsAST);

   void CleanTemporaryFiles();
   bool Parse(llvm::MemoryBuffer *OverrideMainBuffer);

   std::pair<llvm::MemoryBuffer *, std::pair<unsigned, bool> >
   ComputePreamble(CompilerInvocation &Invocation,
                   unsigned MaxLines, bool &CreatedBuffer);

   llvm::MemoryBuffer *getMainBufferWithPrecompiledPreamble(
                                          CompilerInvocation PreambleInvocation,
                                                      bool AllowRebuild = true,
                                                         unsigned MaxLines = 0);
   void RealizeTopLevelDeclsFromPreamble();

 public:
   class ConcurrencyCheck {
     volatile ASTUnit &Self;

   public:
     explicit ConcurrencyCheck(ASTUnit &Self)
       : Self(Self)
     {
       assert(Self.ConcurrencyCheckValue == CheckUnlocked &&
              "Concurrent access to ASTUnit!");
       Self.ConcurrencyCheckValue = CheckLocked;
     }

     ~ConcurrencyCheck() {
       Self.ConcurrencyCheckValue = CheckUnlocked;
     }
   };
   friend class ConcurrencyCheck;

   ~ASTUnit();

   bool isMainFileAST() const { return MainFileIsAST; }

   bool isUnsafeToFree() const { return UnsafeToFree; }
   void setUnsafeToFree(bool Value) { UnsafeToFree = Value; }

   const Diagnostic &getDiagnostics() const { return *Diagnostics; }
   Diagnostic &getDiagnostics()             { return *Diagnostics; }

   const SourceManager &getSourceManager() const { return *SourceMgr; }
         SourceManager &getSourceManager()       { return *SourceMgr; }

   const Preprocessor &getPreprocessor() const { return *PP.get(); }
         Preprocessor &getPreprocessor()       { return *PP.get(); }

   const ASTContext &getASTContext() const { return *Ctx.get(); }
         ASTContext &getASTContext()       { return *Ctx.get(); }

   bool hasSema() const { return TheSema; }
   Sema &getSema() const {
     assert(TheSema && "ASTUnit does not have a Sema object!");
     return *TheSema;
   }

   const FileManager &getFileManager() const { return *FileMgr; }
         FileManager &getFileManager()       { return *FileMgr; }

   const std::string &getOriginalSourceFileName();
   const std::string &getASTFileName();

   /// \brief Add a temporary file that the ASTUnit depends on.
   ///
   /// This file will be erased when the ASTUnit is destroyed.
   void addTemporaryFile(const llvm::sys::Path &TempFile) {
     TemporaryFiles.push_back(TempFile);
   }

   bool getOnlyLocalDecls() const { return OnlyLocalDecls; }

   /// \brief Retrieve the maximum PCH level of declarations that a
   /// traversal of the translation unit should consider.
   unsigned getMaxPCHLevel() const;

   void setLastASTLocation(ASTLocation ALoc) { LastLoc = ALoc; }
   ASTLocation getLastASTLocation() const { return LastLoc; }

   typedef std::vector<Decl *>::iterator top_level_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();
   }

   /// \brief Add a new top-level declaration.
   void addTopLevelDecl(Decl *D) {
     TopLevelDecls.push_back(D);
   }

   /// \brief Add a new top-level declaration, identified by its ID in
   /// the precompiled preamble.
   void addTopLevelDeclFromPreamble(serialization::DeclID D) {
     TopLevelDeclsInPreamble.push_back(D);
   }

   /// \brief Retrieve the mapping from File IDs to the preprocessed entities
   /// within that file.
   PreprocessedEntitiesByFileMap &getPreprocessedEntitiesByFile() {
     return PreprocessedEntitiesByFile;
   }

   // Retrieve the diagnostics associated with this AST
   typedef const StoredDiagnostic *stored_diag_iterator;
   stored_diag_iterator stored_diag_begin() const {
     return StoredDiagnostics.begin();
   }
   stored_diag_iterator stored_diag_end() const {
     return StoredDiagnostics.end();
   }
   unsigned stored_diag_size() const { return StoredDiagnostics.size(); }

   llvm::SmallVector<StoredDiagnostic, 4> &getStoredDiagnostics() {
     return StoredDiagnostics;
   }

   typedef std::vector<CachedCodeCompletionResult>::iterator
     cached_completion_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();
   }

   /// \brief Whether this AST represents a complete translation unit.
   ///
   /// If false, this AST is only a partial translation unit, e.g., one
   /// that might still be used as a precompiled header or preamble.
   bool isCompleteTranslationUnit() const { return CompleteTranslationUnit; }

   /// \brief A mapping from a file name to the memory buffer that stores the
   /// remapped contents of that file.
   typedef std::pair<std::string, const llvm::MemoryBuffer *> RemappedFile;

   /// \brief Create a ASTUnit from an AST file.
   ///
   /// \param Filename - The AST file to load.
   ///
   /// \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 ASTUnit *LoadFromASTFile(const std::string &Filename,
                                   llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
                                   bool OnlyLocalDecls = false,
                                   RemappedFile *RemappedFiles = 0,
                                   unsigned NumRemappedFiles = 0,
                                   bool CaptureDiagnostics = false);

   /// 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 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 ASTUnit *LoadFromCompilerInvocation(CompilerInvocation *CI,
                                      llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
                                              bool OnlyLocalDecls = false,
                                              bool CaptureDiagnostics = false,
                                              bool PrecompilePreamble = false,
                                           bool CompleteTranslationUnit = true,
                                        bool CacheCodeCompletionResults = 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 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.
   //
   // 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,
                                     llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
                                       llvm::StringRef ResourceFilesPath,
                                       bool OnlyLocalDecls = false,
                                       RemappedFile *RemappedFiles = 0,
                                       unsigned NumRemappedFiles = 0,
                                       bool CaptureDiagnostics = false,
                                       bool PrecompilePreamble = false,
                                       bool CompleteTranslationUnit = true,
                                       bool CacheCodeCompletionResults = false);

   /// \brief Reparse the source files using the same command-line options that
   /// were originally used to produce this translation unit.
   ///
   /// \returns True if a failure occurred that causes the ASTUnit not to
   /// contain any translation-unit information, false otherwise.
   bool Reparse(RemappedFile *RemappedFiles = 0,
                unsigned NumRemappedFiles = 0);

   /// \brief 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.
   ///
   /// FIXME: The Diag, LangOpts, SourceMgr, FileMgr, StoredDiagnostics, and
   /// OwnedBuffers parameters are all disgusting hacks. They will go away.
   void CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
                     RemappedFile *RemappedFiles, unsigned NumRemappedFiles,
                     bool IncludeMacros, bool IncludeCodePatterns,
                     CodeCompleteConsumer &Consumer,
                     Diagnostic &Diag, LangOptions &LangOpts,
                     SourceManager &SourceMgr, FileManager &FileMgr,
                     llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
               llvm::SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers);

   /// \brief Save this translation unit to a file with the given name.
   ///
   /// \returns True if an error occurred, false otherwise.
   bool Save(llvm::StringRef File);
 };

 } // namespace clang

 #endif
	//===--- ASTUnit.h - ASTUnit utility ----------------------------- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// ASTUnit utility class.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_CLANG_FRONTEND_ASTUNIT_H
	#define LLVM_CLANG_FRONTEND_ASTUNIT_H

	#include "clang/Index/ASTLocation.h"
	#include "clang/Serialization/ASTBitCodes.h"
	#include "clang/Sema/Sema.h"
	#include "clang/Sema/CodeCompleteConsumer.h"
	#include "clang/Lex/PreprocessingRecord.h"
	#include "clang/Basic/SourceManager.h"
	#include "clang/Basic/FileManager.h"
	#include "clang-c/Index.h"
	#include "llvm/ADT/IntrusiveRefCntPtr.h"
	#include "llvm/ADT/OwningPtr.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/ADT/StringMap.h"
	#include "llvm/System/Path.h"
	#include "llvm/Support/Timer.h"
	#include <map>
	#include <string>
	#include <vector>
	#include <cassert>
	#include <utility>
	#include <sys/types.h>

	namespace llvm {
	class MemoryBuffer;
	}

	namespace clang {
	class ASTContext;
	class CodeCompleteConsumer;
	class CompilerInvocation;
	class Decl;
	class Diagnostic;
	class FileEntry;
	class FileManager;
	class HeaderSearch;
	class Preprocessor;
	class SourceManager;
	class TargetInfo;

	using namespace idx;

	/// \brief Utility class for loading a ASTContext from an AST file.
	///
	class ASTUnit {
	public:
	typedef std::map<FileID, std::vector<PreprocessedEntity *> >
	PreprocessedEntitiesByFileMap;

	private:
	llvm::IntrusiveRefCntPtr<Diagnostic> Diagnostics;
	llvm::OwningPtr<FileManager> FileMgr;
	llvm::OwningPtr<SourceManager> SourceMgr;
	llvm::OwningPtr<HeaderSearch> HeaderInfo;
	llvm::OwningPtr<TargetInfo> Target;
	llvm::OwningPtr<Preprocessor> PP;
	llvm::OwningPtr<ASTContext> Ctx;

	/// \brief The AST consumer that received information about the translation
	/// unit as it was parsed or loaded.
	llvm::OwningPtr<ASTConsumer> Consumer;

	/// \brief The semantic analysis object used to type-check the translation
	/// unit.
	llvm::OwningPtr<Sema> TheSema;

	/// Optional owned invocation, just used to make the invocation used in
	/// LoadFromCommandLine available.
	llvm::OwningPtr<CompilerInvocation> Invocation;

	// 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;

	/// \brief Whether to capture any diagnostics produced.
	bool CaptureDiagnostics;

	/// \brief Track whether the main file was loaded from an AST or not.
	bool MainFileIsAST;

	/// \brief Whether this AST represents a complete translation unit.
	bool CompleteTranslationUnit;

	/// 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;

	/// The name of the original source file used to generate this ASTUnit.
	std::string OriginalSourceFile;

	// Critical optimization when using clang_getCursor().
	ASTLocation LastLoc;

	/// \brief The set of diagnostics produced when creating this
	/// translation unit.
	llvm::SmallVector<StoredDiagnostic, 4> StoredDiagnostics;

	/// \brief Temporary files that should be removed when the ASTUnit is
	/// destroyed.
	llvm::SmallVector<llvm::sys::Path, 4> TemporaryFiles;

	/// \brief A mapping from file IDs to the set of preprocessed entities
	/// stored in that file.
	///
	/// FIXME: This is just an optimization hack to avoid searching through
	/// many preprocessed entities during cursor traversal in the CIndex library.
	/// Ideally, we would just be able to perform a binary search within the
	/// list of preprocessed entities.
	PreprocessedEntitiesByFileMap PreprocessedEntitiesByFile;

	/// \brief Simple hack to allow 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.
	unsigned int ConcurrencyCheckValue;
	static const unsigned int CheckLocked = 28573289;
	static const unsigned int CheckUnlocked = 9803453;

	/// \brief 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;

	/// \brief The file in which the precompiled preamble is stored.
	std::string PreambleFile;

	/// \brief The contents of the preamble that has been precompiled to
	/// \c PreambleFile.
	std::vector<char> Preamble;

	/// \brief Whether the preamble ends at the start of a new line.
	///
	/// Used to inform the lexer as to whether it's starting at the beginning of
	/// a line after skipping the preamble.
	bool PreambleEndsAtStartOfLine;

	/// \brief The size of the source buffer that we've reserved for the main
	/// file within the precompiled preamble.
	unsigned PreambleReservedSize;

	/// \brief Keeps track of the files that were used when computing the
	/// preamble, with both their buffer size and their modification time.
	///
	/// If any of the files have changed from one compile to the next,
	/// the preamble must be thrown away.
	llvm::StringMap<std::pair<off_t, time_t> > FilesInPreamble;

	/// \brief 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.
	llvm::MemoryBuffer *SavedMainFileBuffer;

	/// \brief When non-NULL, this is the buffer used to store the
	/// contents of the preamble when it has been padded to build the
	/// precompiled preamble.
	llvm::MemoryBuffer *PreambleBuffer;

	/// \brief The number of warnings that occurred while parsing the preamble.
	///
	/// This value will be used to restore the state of the \c Diagnostic 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;

	/// \brief The number of diagnostics that were stored when parsing
	/// the precompiled preamble.
	///
	/// This value is used to determine how many of the stored
	/// diagnostics should be retained when reparsing in the presence of
	/// a precompiled preamble.
	unsigned NumStoredDiagnosticsInPreamble;

	/// \brief The group of timers associated with this translation unit.
	llvm::OwningPtr<llvm::TimerGroup> TimerGroup;

	/// \brief A list of the serialization ID numbers for each of the top-level
	/// declarations parsed within the precompiled preamble.
	std::vector<serialization::DeclID> TopLevelDeclsInPreamble;

	///
	/// \defgroup CodeCompleteCaching Code-completion caching
	///
	/// \{
	///

	/// \brief Whether we should be caching code-completion results.
	bool ShouldCacheCodeCompletionResults;

	public:
	/// \brief A cached code-completion result, which may be introduced in one of
	/// many different contexts.
	struct CachedCodeCompletionResult {
	/// \brief The code-completion string corresponding to this completion
	/// result.
	CodeCompletionString *Completion;

	/// \brief 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, subtract one from the completion context kind and shift 1 by that
	/// number of bits. Many completions can occur in several different
	/// contexts.
	unsigned ShowInContexts;

	/// \brief The priority given to this code-completion result.
	unsigned Priority;

	/// \brief The libclang cursor kind corresponding to this code-completion
	/// result.
	CXCursorKind Kind;

	/// \brief The availability of this code-completion result.
	CXAvailabilityKind Availability;

	/// \brief The simplified type class for a non-macro completion result.
	SimplifiedTypeClass TypeClass;

	/// \brief 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;
	};

	/// \brief Retrieve the mapping from formatted type names to unique type
	/// identifiers.
	llvm::StringMap<unsigned> &getCachedCompletionTypes() {
	return CachedCompletionTypes;
	}

	private:
	/// \brief The set of cached code-completion results.
	std::vector<CachedCodeCompletionResult> CachedCompletionResults;

	/// \brief 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;

	/// \brief The number of top-level declarations present the last time we
	/// cached code-completion results.
	///
	/// The value is used to help detect when we should repopulate the global
	/// completion cache.
	unsigned NumTopLevelDeclsAtLastCompletionCache;

	/// \brief The number of reparses left until we'll consider updating the
	/// code-completion cache.
	///
	/// This is meant to avoid thrashing during reparsing, by not allowing the
	/// code-completion cache to be updated on every reparse.
	unsigned CacheCodeCompletionCoolDown;

	/// \brief 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 Cache any "global" code-completion results, so that we can avoid
	/// recomputing them with each completion.
	void CacheCodeCompletionResults();

	/// \brief Clear out and deallocate
	void ClearCachedCompletionResults();

	///
	/// \}
	///

	/// \brief The timers we've created from the various parses, reparses, etc.
	/// involved in this translation unit.
	std::vector<llvm::Timer *> Timers;

	ASTUnit(const ASTUnit&); // DO NOT IMPLEMENT
	ASTUnit &operator=(const ASTUnit &); // DO NOT IMPLEMENT

	explicit ASTUnit(bool MainFileIsAST);

	void CleanTemporaryFiles();
	bool Parse(llvm::MemoryBuffer *OverrideMainBuffer);

	std::pair<llvm::MemoryBuffer *, std::pair<unsigned, bool> >
	ComputePreamble(CompilerInvocation &Invocation,
	unsigned MaxLines, bool &CreatedBuffer);

	llvm::MemoryBuffer *getMainBufferWithPrecompiledPreamble(
	CompilerInvocation PreambleInvocation,
	bool AllowRebuild = true,
	unsigned MaxLines = 0);
	void RealizeTopLevelDeclsFromPreamble();

	public:
	class ConcurrencyCheck {
	volatile ASTUnit &Self;

	public:
	explicit ConcurrencyCheck(ASTUnit &Self)
	: Self(Self)
	{
	assert(Self.ConcurrencyCheckValue == CheckUnlocked &&
	"Concurrent access to ASTUnit!");
	Self.ConcurrencyCheckValue = CheckLocked;
	}

	~ConcurrencyCheck() {
	Self.ConcurrencyCheckValue = CheckUnlocked;
	}
	};
	friend class ConcurrencyCheck;

	~ASTUnit();

	bool isMainFileAST() const { return MainFileIsAST; }

	bool isUnsafeToFree() const { return UnsafeToFree; }
	void setUnsafeToFree(bool Value) { UnsafeToFree = Value; }

	const Diagnostic &getDiagnostics() const { return *Diagnostics; }
	Diagnostic &getDiagnostics() { return *Diagnostics; }

	const SourceManager &getSourceManager() const { return *SourceMgr; }
	SourceManager &getSourceManager() { return *SourceMgr; }

	const Preprocessor &getPreprocessor() const { return *PP.get(); }
	Preprocessor &getPreprocessor() { return *PP.get(); }

	const ASTContext &getASTContext() const { return *Ctx.get(); }
	ASTContext &getASTContext() { return *Ctx.get(); }

	bool hasSema() const { return TheSema; }
	Sema &getSema() const {
	assert(TheSema && "ASTUnit does not have a Sema object!");
	return *TheSema;
	}

	const FileManager &getFileManager() const { return *FileMgr; }
	FileManager &getFileManager() { return *FileMgr; }

	const std::string &getOriginalSourceFileName();
	const std::string &getASTFileName();

	/// \brief Add a temporary file that the ASTUnit depends on.
	///
	/// This file will be erased when the ASTUnit is destroyed.
	void addTemporaryFile(const llvm::sys::Path &TempFile) {
	TemporaryFiles.push_back(TempFile);
	}

	bool getOnlyLocalDecls() const { return OnlyLocalDecls; }

	/// \brief Retrieve the maximum PCH level of declarations that a
	/// traversal of the translation unit should consider.
	unsigned getMaxPCHLevel() const;

	void setLastASTLocation(ASTLocation ALoc) { LastLoc = ALoc; }
	ASTLocation getLastASTLocation() const { return LastLoc; }

	typedef std::vector<Decl *>::iterator top_level_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();
	}

	/// \brief Add a new top-level declaration.
	void addTopLevelDecl(Decl *D) {
	TopLevelDecls.push_back(D);
	}

	/// \brief Add a new top-level declaration, identified by its ID in
	/// the precompiled preamble.
	void addTopLevelDeclFromPreamble(serialization::DeclID D) {
	TopLevelDeclsInPreamble.push_back(D);
	}

	/// \brief Retrieve the mapping from File IDs to the preprocessed entities
	/// within that file.
	PreprocessedEntitiesByFileMap &getPreprocessedEntitiesByFile() {
	return PreprocessedEntitiesByFile;
	}

	// Retrieve the diagnostics associated with this AST
	typedef const StoredDiagnostic *stored_diag_iterator;
	stored_diag_iterator stored_diag_begin() const {
	return StoredDiagnostics.begin();
	}
	stored_diag_iterator stored_diag_end() const {
	return StoredDiagnostics.end();
	}
	unsigned stored_diag_size() const { return StoredDiagnostics.size(); }

	llvm::SmallVector<StoredDiagnostic, 4> &getStoredDiagnostics() {
	return StoredDiagnostics;
	}

	typedef std::vector<CachedCodeCompletionResult>::iterator
	cached_completion_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();
	}

	/// \brief Whether this AST represents a complete translation unit.
	///
	/// If false, this AST is only a partial translation unit, e.g., one
	/// that might still be used as a precompiled header or preamble.
	bool isCompleteTranslationUnit() const { return CompleteTranslationUnit; }

	/// \brief A mapping from a file name to the memory buffer that stores the
	/// remapped contents of that file.
	typedef std::pair<std::string, const llvm::MemoryBuffer *> RemappedFile;

	/// \brief Create a ASTUnit from an AST file.
	///
	/// \param Filename - The AST file to load.
	///
	/// \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 ASTUnit *LoadFromASTFile(const std::string &Filename,
	llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
	bool OnlyLocalDecls = false,
	RemappedFile *RemappedFiles = 0,
	unsigned NumRemappedFiles = 0,
	bool CaptureDiagnostics = false);

	/// 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 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 ASTUnit LoadFromCompilerInvocation(CompilerInvocation CI,
	llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
	bool OnlyLocalDecls = false,
	bool CaptureDiagnostics = false,
	bool PrecompilePreamble = false,
	bool CompleteTranslationUnit = true,
	bool CacheCodeCompletionResults = 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 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.
	//
	// 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,
	llvm::IntrusiveRefCntPtr<Diagnostic> Diags,
	llvm::StringRef ResourceFilesPath,
	bool OnlyLocalDecls = false,
	RemappedFile *RemappedFiles = 0,
	unsigned NumRemappedFiles = 0,
	bool CaptureDiagnostics = false,
	bool PrecompilePreamble = false,
	bool CompleteTranslationUnit = true,
	bool CacheCodeCompletionResults = false);

	/// \brief Reparse the source files using the same command-line options that
	/// were originally used to produce this translation unit.
	///
	/// \returns True if a failure occurred that causes the ASTUnit not to
	/// contain any translation-unit information, false otherwise.
	bool Reparse(RemappedFile *RemappedFiles = 0,
	unsigned NumRemappedFiles = 0);

	/// \brief 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.
	///
	/// FIXME: The Diag, LangOpts, SourceMgr, FileMgr, StoredDiagnostics, and
	/// OwnedBuffers parameters are all disgusting hacks. They will go away.
	void CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
	RemappedFile *RemappedFiles, unsigned NumRemappedFiles,
	bool IncludeMacros, bool IncludeCodePatterns,
	CodeCompleteConsumer &Consumer,
	Diagnostic &Diag, LangOptions &LangOpts,
	SourceManager &SourceMgr, FileManager &FileMgr,
	llvm::SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
	llvm::SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers);

	/// \brief Save this translation unit to a file with the given name.
	///
	/// \returns True if an error occurred, false otherwise.
	bool Save(llvm::StringRef File);
	};

	} // namespace clang

	#endif