aboutsummaryrefslogtreecommitdiffstats
path: root/include/clang/Frontend/ASTUnit.h
blob: 46395cf6e861274ad0f544037ae52f555c245efb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
//===--- 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-c/Index.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/FileSystemOptions.h"
#include "clang/Basic/LangOptions.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 "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/MD5.h"
#include <cassert>
#include <memory>
#include <string>
#include <sys/types.h>
#include <utility>
#include <vector>

namespace llvm {
  class MemoryBuffer;
}

namespace clang {
class Sema;
class ASTContext;
class ASTReader;
class CompilerInvocation;
class CompilerInstance;
class Decl;
class DiagnosticsEngine;
class FileEntry;
class FileManager;
class HeaderSearch;
class MemoryBufferCache;
class Preprocessor;
class PCHContainerOperations;
class PCHContainerReader;
class TargetInfo;
class FrontendAction;
class ASTDeserializationListener;

/// \brief Utility class for loading a ASTContext from an AST file.
///
class ASTUnit : public ModuleLoader {
public:
  struct StandaloneFixIt {
    std::pair<unsigned, unsigned> RemoveRange;
    std::pair<unsigned, unsigned> InsertFromRange;
    std::string CodeToInsert;
    bool BeforePreviousInsertions;
  };

  struct StandaloneDiagnostic {
    unsigned ID;
    DiagnosticsEngine::Level Level;
    std::string Message;
    std::string Filename;
    unsigned LocOffset;
    std::vector<std::pair<unsigned, unsigned> > Ranges;
    std::vector<StandaloneFixIt> FixIts;
  };

private:
  std::shared_ptr<LangOptions>            LangOpts;
  IntrusiveRefCntPtr<DiagnosticsEngine>   Diagnostics;
  IntrusiveRefCntPtr<FileManager>         FileMgr;
  IntrusiveRefCntPtr<SourceManager>       SourceMgr;
  IntrusiveRefCntPtr<MemoryBufferCache>   PCMCache;
  std::unique_ptr<HeaderSearch>           HeaderInfo;
  IntrusiveRefCntPtr<TargetInfo>          Target;
  std::shared_ptr<Preprocessor>           PP;
  IntrusiveRefCntPtr<ASTContext>          Ctx;
  std::shared_ptr<TargetOptions>          TargetOpts;
  std::shared_ptr<HeaderSearchOptions>    HSOpts;
  IntrusiveRefCntPtr<ASTReader> Reader;
  bool HadModuleLoaderFatalFailure;

  struct ASTWriterData;
  std::unique_ptr<ASTWriterData> WriterData;

  FileSystemOptions FileSystemOpts;

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

  /// \brief 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;

  // 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 What kind of translation unit this AST represents.
  TranslationUnitKind TUKind;

  /// \brief Whether we should time each operation.
  bool WantTiming;

  /// \brief Whether the ASTUnit should delete the remapped buffers.
  bool OwnsRemappedFileBuffers;
  
  /// 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;

  /// \brief Sorted (by file offset) vector of pairs of file offset/Decl.
  typedef SmallVector<std::pair<unsigned, Decl *>, 64> LocDeclsTy;
  typedef llvm::DenseMap<FileID, LocDeclsTy *> FileDeclsTy;

  /// \brief 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;

  /// \brief The set of diagnostics produced when creating the preamble.
  SmallVector<StandaloneDiagnostic, 4> PreambleDiagnostics;

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

  /// \brief The set of diagnostics produced when failing to parse, e.g. due
  /// to failure to load the PCH.
  SmallVector<StoredDiagnostic, 4> FailedParseDiagnostics;

  /// \brief 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;
  
  /// \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;

public:
  class PreambleData {
    const FileEntry *File;
    std::vector<char> Buffer;
    mutable unsigned NumLines;
    
  public:
    PreambleData() : File(nullptr), NumLines(0) { }
    
    void assign(const FileEntry *F, const char *begin, const char *end) {
      File = F;
      Buffer.assign(begin, end);
      NumLines = 0;
    }

    void clear() { Buffer.clear(); File = nullptr; NumLines = 0; }

    size_t size() const { return Buffer.size(); }
    bool empty() const { return Buffer.empty(); }

    const char *getBufferStart() const { return &Buffer[0]; }

    unsigned getNumLines() const {
      if (NumLines)
        return NumLines;
      countLines();
      return NumLines;
    }

    SourceRange getSourceRange(const SourceManager &SM) const {
      SourceLocation FileLoc = SM.getLocForStartOfFile(SM.getPreambleFileID());
      return SourceRange(FileLoc, FileLoc.getLocWithOffset(size()-1));
    }

  private:
    void countLines() const;
  };

  const PreambleData &getPreambleData() const {
    return Preamble;
  }

  /// Data used to determine if a file used in the preamble has been changed.
  struct PreambleFileHash {
    /// All files have size set.
    off_t Size;

    /// Modification time is set for files that are on disk.  For memory
    /// buffers it is zero.
    time_t ModTime;

    /// Memory buffers have MD5 instead of modification time.  We don't
    /// compute MD5 for on-disk files because we hope that modification time is
    /// enough to tell if the file was changed.
    llvm::MD5::MD5Result MD5;

    static PreambleFileHash createForFile(off_t Size, time_t ModTime);
    static PreambleFileHash
    createForMemoryBuffer(const llvm::MemoryBuffer *Buffer);

    friend bool operator==(const PreambleFileHash &LHS,
                           const PreambleFileHash &RHS);

    friend bool operator!=(const PreambleFileHash &LHS,
                           const PreambleFileHash &RHS) {
      return !(LHS == RHS);
    }
  };

private:
  /// \brief The contents of the preamble that has been precompiled to
  /// \c PreambleFile.
  PreambleData 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 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<PreambleFileHash> 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.
  std::unique_ptr<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.
  std::unique_ptr<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 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;

  /// \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;
  
  /// \brief Whether we should be caching code-completion results.
  bool ShouldCacheCodeCompletionResults : 1;

  /// \brief Whether to include brief documentation within the set of code
  /// completions cached.
  bool IncludeBriefCommentsInCodeCompletion : 1;

  /// \brief True if non-system source files should be treated as volatile
  /// (likely to change while trying to use them).
  bool UserFilesAreVolatile : 1;
 
  /// \brief The language options used when we load an AST file.
  LangOptions ASTFileLangOpts;

  static void ConfigureDiags(IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
                             ASTUnit &AST, bool CaptureDiagnostics);

  void TranslateStoredDiagnostics(FileManager &FileMgr,
                                  SourceManager &SrcMan,
                      const SmallVectorImpl<StandaloneDiagnostic> &Diags,
                            SmallVectorImpl<StoredDiagnostic> &Out);

  void clearFileLevelDecls();

public:
  /// \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, shift 1 by that number of bits. Many completions can occur in
    /// several different contexts.
    uint64_t 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; 
  }
  
  /// \brief Retrieve the allocator used to cache global code completions.
  std::shared_ptr<GlobalCodeCompletionAllocator>
  getCachedCompletionAllocator() {
    return CachedCompletionAllocator;
  }

  CodeCompletionTUInfo &getCodeCompletionTUInfo() {
    if (!CCTUInfo)
      CCTUInfo = llvm::make_unique<CodeCompletionTUInfo>(
          std::make_shared<GlobalCodeCompletionAllocator>());
    return *CCTUInfo;
  }

private:
  /// \brief Allocator used to store cached code completions.
  std::shared_ptr<GlobalCodeCompletionAllocator> CachedCompletionAllocator;

  std::unique_ptr<CodeCompletionTUInfo> CCTUInfo;

  /// \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 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;

  /// \brief 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;

  /// \brief The current hash value for the top-level declaration and macro
  /// definition names
  unsigned CurrentTopLevelHashValue;
  
  /// \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();
  
  ASTUnit(const ASTUnit &) = delete;
  void operator=(const ASTUnit &) = delete;
  
  explicit ASTUnit(bool MainFileIsAST);

  bool Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
             std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer);

  struct ComputedPreamble {
    llvm::MemoryBuffer *Buffer;
    std::unique_ptr<llvm::MemoryBuffer> Owner;
    unsigned Size;
    bool PreambleEndsAtStartOfLine;
    ComputedPreamble(llvm::MemoryBuffer *Buffer,
                     std::unique_ptr<llvm::MemoryBuffer> Owner, unsigned Size,
                     bool PreambleEndsAtStartOfLine)
        : Buffer(Buffer), Owner(std::move(Owner)), Size(Size),
          PreambleEndsAtStartOfLine(PreambleEndsAtStartOfLine) {}
  };
  ComputedPreamble ComputePreamble(CompilerInvocation &Invocation,
                                   unsigned MaxLines);

  std::unique_ptr<llvm::MemoryBuffer> getMainBufferWithPrecompiledPreamble(
      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
      const CompilerInvocation &PreambleInvocationIn, bool AllowRebuild = true,
      unsigned MaxLines = 0);
  void RealizeTopLevelDeclsFromPreamble();

  /// \brief Transfers ownership of the objects (like SourceManager) from
  /// \param CI to this ASTUnit.
  void transferASTDataFromCompilerInstance(CompilerInstance &CI);

  /// \brief Allows us to assert that ASTUnit is not being used concurrently,
  /// which is not supported.
  ///
  /// Clients should create instances of the ConcurrencyCheck class whenever
  /// using the ASTUnit in a way that isn't intended to be concurrent, which is
  /// just about any usage.
  /// Becomes a noop in release mode; only useful for debug mode checking.
  class ConcurrencyState {
    void *Mutex; // a llvm::sys::MutexImpl in debug;

  public:
    ConcurrencyState();
    ~ConcurrencyState();

    void start();
    void finish();
  };
  ConcurrencyState ConcurrencyCheckValue;

public:
  class ConcurrencyCheck {
    ASTUnit &Self;
    
  public:
    explicit ConcurrencyCheck(ASTUnit &Self)
      : Self(Self) 
    { 
      Self.ConcurrencyCheckValue.start();
    }
    ~ConcurrencyCheck() {
      Self.ConcurrencyCheckValue.finish();
    }
  };
  friend class ConcurrencyCheck;

  ~ASTUnit() override;

  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);

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

  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }

  IntrusiveRefCntPtr<ASTReader> getASTReader() const;

  StringRef getOriginalSourceFileName() {
    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;

  /// \brief If this ASTUnit came from an AST file, returns the filename for it.
  StringRef getASTFileName() const;

  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 local file-level declaration.
  void addFileLevelDecl(Decl *D);

  /// \brief 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);

  /// \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 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; }

  /// \brief 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;

  /// \brief Get the source location for the given file:offset pair.
  SourceLocation getLocation(const FileEntry *File, unsigned Offset) const;

  /// \brief 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);

  /// \brief 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);

  bool isInPreambleFileID(SourceLocation Loc);
  bool isInMainFileID(SourceLocation Loc);
  SourceLocation getStartOfMainFileID();
  SourceLocation getEndOfPreambleFileID();

  /// \see mapLocationFromPreamble.
  SourceRange mapRangeFromPreamble(SourceRange R) {
    return SourceRange(mapLocationFromPreamble(R.getBegin()),
                       mapLocationFromPreamble(R.getEnd()));
  }

  /// \see mapLocationToPreamble.
  SourceRange mapRangeToPreamble(SourceRange R) {
    return SourceRange(mapLocationToPreamble(R.getBegin()),
                       mapLocationToPreamble(R.getEnd()));
  }
  
  // Retrieve the diagnostics associated with this AST
  typedef StoredDiagnostic *stored_diag_iterator;
  typedef const StoredDiagnostic *stored_diag_const_iterator;
  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; 
  }

  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 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;

  /// \brief Type for a function iterating over a number of declarations.
  /// \returns true to continue iteration and false to abort.
  typedef bool (*DeclVisitorFn)(void *context, const Decl *D);

  /// \brief 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);

  /// \brief Get the PCH file if one was included.
  const FileEntry *getPCHFile();

  /// \brief Returns true if the ASTUnit was constructed from a serialized
  /// module file.
  bool isModuleFile();

  std::unique_ptr<llvm::MemoryBuffer>
  getBufferForFile(StringRef Filename, std::string *ErrorStr = nullptr);

  /// \brief Determine what kind of translation unit this AST represents.
  TranslationUnitKind getTranslationUnitKind() const { return TUKind; }

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

  /// \brief Create a ASTUnit. Gets ownership of the passed CompilerInvocation.
  static std::unique_ptr<ASTUnit>
  create(std::shared_ptr<CompilerInvocation> CI,
         IntrusiveRefCntPtr<DiagnosticsEngine> Diags, bool CaptureDiagnostics,
         bool UserFilesAreVolatile);

  /// \brief 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,
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
      const FileSystemOptions &FileSystemOpts, bool UseDebugInfo = false,
      bool OnlyLocalDecls = false, ArrayRef<RemappedFile> RemappedFiles = None,
      bool CaptureDiagnostics = false, bool AllowPCHWithCompilerErrors = false,
      bool UserFilesAreVolatile = false);

private:
  /// \brief 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.
  ///
  /// \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);

public:
  
  /// \brief Create an ASTUnit from a source file, via a CompilerInvocation
  /// object, by invoking the optionally provided ASTFrontendAction. 
  ///
  /// \param CI - The compiler invocation to use; it must have exactly one input
  /// source file. The ASTUnit takes ownership of the CompilerInvocation object.
  ///
  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
  /// creating modules.
  ///
  /// \param Diags - The diagnostics engine to use for reporting errors; its
  /// lifetime is expected to extend past that of the returned ASTUnit.
  ///
  /// \param Action - The ASTFrontendAction to invoke. Its ownership is not
  /// transferred.
  ///
  /// \param Unit - optionally an already created ASTUnit. Its ownership is not
  /// transferred.
  ///
  /// \param Persistent - if true the returned ASTUnit will be complete.
  /// false means the caller is only interested in getting info through the
  /// provided \see Action.
  ///
  /// \param ErrAST - If non-null and parsing failed without any AST to return
  /// (e.g. because the PCH could not be loaded), this accepts the ASTUnit
  /// mainly to allow the caller to see the diagnostics.
  /// This will only receive an ASTUnit if a new one was created. If an already
  /// created ASTUnit was passed in \p Unit then the caller can check that.
  ///
  static ASTUnit *LoadFromCompilerInvocationAction(
      std::shared_ptr<CompilerInvocation> CI,
      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
      FrontendAction *Action = nullptr, ASTUnit *Unit = nullptr,
      bool Persistent = true, StringRef ResourceFilesPath = StringRef(),
      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
      unsigned PrecompilePreambleAfterNParses = 0,
      bool CacheCodeCompletionResults = false,
      bool IncludeBriefCommentsInCodeCompletion = false,
      bool UserFilesAreVolatile = false,
      std::unique_ptr<ASTUnit> *ErrAST = nullptr);

  /// LoadFromCompilerInvocation - Create an ASTUnit from a source file, via a
  /// CompilerInvocation object.
  ///
  /// \param CI - The compiler invocation to use; it must have exactly one input
  /// source file. The ASTUnit takes ownership of the CompilerInvocation object.
  ///
  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
  /// creating modules.
  ///
  /// \param Diags - The diagnostics engine to use for reporting errors; its
  /// lifetime is expected to extend past that of the returned ASTUnit.
  //
  // FIXME: Move OnlyLocalDecls, UseBumpAllocator to setters on the ASTUnit, we
  // shouldn't need to specify them at construction time.
  static std::unique_ptr<ASTUnit> LoadFromCompilerInvocation(
      std::shared_ptr<CompilerInvocation> CI,
      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags, FileManager *FileMgr,
      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
      unsigned PrecompilePreambleAfterNParses = 0,
      TranslationUnitKind TUKind = TU_Complete,
      bool CacheCodeCompletionResults = false,
      bool IncludeBriefCommentsInCodeCompletion = false,
      bool UserFilesAreVolatile = false);

  /// LoadFromCommandLine - Create an ASTUnit from a vector of command line
  /// arguments, which must specify exactly one source file.
  ///
  /// \param ArgBegin - The beginning of the argument vector.
  ///
  /// \param ArgEnd - The end of the argument vector.
  ///
  /// \param PCHContainerOps - The PCHContainerOperations to use for loading and
  /// creating modules.
  ///
  /// \param Diags - The diagnostics engine to use for reporting errors; its
  /// lifetime is expected to extend past that of the returned ASTUnit.
  ///
  /// \param ResourceFilesPath - The path to the compiler resource files.
  ///
  /// \param ModuleFormat - If provided, uses the specific module format.
  ///
  /// \param ErrAST - If non-null and parsing failed without any AST to return
  /// (e.g. because the PCH could not be loaded), this accepts the ASTUnit
  /// mainly to allow the caller to see the diagnostics.
  ///
  // FIXME: Move OnlyLocalDecls, UseBumpAllocator to setters on the ASTUnit, we
  // shouldn't need to specify them at construction time.
  static ASTUnit *LoadFromCommandLine(
      const char **ArgBegin, const char **ArgEnd,
      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
      IntrusiveRefCntPtr<DiagnosticsEngine> Diags, StringRef ResourceFilesPath,
      bool OnlyLocalDecls = false, bool CaptureDiagnostics = false,
      ArrayRef<RemappedFile> RemappedFiles = None,
      bool RemappedFilesKeepOriginalName = true,
      unsigned PrecompilePreambleAfterNParses = 0,
      TranslationUnitKind TUKind = TU_Complete,
      bool CacheCodeCompletionResults = false,
      bool IncludeBriefCommentsInCodeCompletion = false,
      bool AllowPCHWithCompilerErrors = false, bool SkipFunctionBodies = false,
      bool UserFilesAreVolatile = false, bool ForSerialization = false,
      llvm::Optional<StringRef> ModuleFormat = llvm::None,
      std::unique_ptr<ASTUnit> *ErrAST = nullptr);

  /// \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(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
               ArrayRef<RemappedFile> RemappedFiles = None);

  /// \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.
  ///
  /// \param IncludeBriefComments Whether to include brief documentation within
  /// the set of code completions returned.
  ///
  /// FIXME: The Diag, LangOpts, SourceMgr, FileMgr, StoredDiagnostics, and
  /// OwnedBuffers parameters are all disgusting hacks. They will go away.
  void CodeComplete(StringRef File, unsigned Line, unsigned Column,
                    ArrayRef<RemappedFile> RemappedFiles, bool IncludeMacros,
                    bool IncludeCodePatterns, bool IncludeBriefComments,
                    CodeCompleteConsumer &Consumer,
                    std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                    DiagnosticsEngine &Diag, LangOptions &LangOpts,
                    SourceManager &SourceMgr, FileManager &FileMgr,
                    SmallVectorImpl<StoredDiagnostic> &StoredDiagnostics,
                    SmallVectorImpl<const llvm::MemoryBuffer *> &OwnedBuffers);

  /// \brief Save this translation unit to a file with the given name.
  ///
  /// \returns true if there was a file error or false if the save was
  /// successful.
  bool Save(StringRef File);

  /// \brief Serialize this translation unit with the given output stream.
  ///
  /// \returns True if an error occurred, false otherwise.
  bool serialize(raw_ostream &OS);

  ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
                              Module::NameVisibilityKind Visibility,
                              bool IsInclusionDirective) override {
    // ASTUnit doesn't know how to load modules (not that this matters).
    return ModuleLoadResult();
  }

  void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
                         SourceLocation ImportLoc) override {}

  GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override
    { return nullptr; }
  bool lookupMissingImports(StringRef Name, SourceLocation TriggerLoc) override
    { return 0; }
};

} // namespace clang

#endif