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      1 //===--- PreprocessingRecord.h - Record of Preprocessing --------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines the PreprocessingRecord class, which maintains a record
     11 //  of what occurred during preprocessing.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 #ifndef LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
     15 #define LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
     16 
     17 #include "clang/Basic/IdentifierTable.h"
     18 #include "clang/Basic/SourceLocation.h"
     19 #include "clang/Lex/PPCallbacks.h"
     20 #include "llvm/ADT/DenseMap.h"
     21 #include "llvm/ADT/Optional.h"
     22 #include "llvm/ADT/SmallVector.h"
     23 #include "llvm/Support/Allocator.h"
     24 #include "llvm/Support/Compiler.h"
     25 #include <vector>
     26 
     27 namespace clang {
     28   class IdentifierInfo;
     29   class MacroInfo;
     30   class PreprocessingRecord;
     31 }
     32 
     33 /// \brief Allocates memory within a Clang preprocessing record.
     34 void* operator new(size_t bytes, clang::PreprocessingRecord& PR,
     35                    unsigned alignment = 8) throw();
     36 
     37 /// \brief Frees memory allocated in a Clang preprocessing record.
     38 void operator delete(void* ptr, clang::PreprocessingRecord& PR,
     39                      unsigned) throw();
     40 
     41 namespace clang {
     42   class MacroDefinition;
     43   class FileEntry;
     44 
     45   /// \brief Base class that describes a preprocessed entity, which may be a
     46   /// preprocessor directive or macro expansion.
     47   class PreprocessedEntity {
     48   public:
     49     /// \brief The kind of preprocessed entity an object describes.
     50     enum EntityKind {
     51       /// \brief Indicates a problem trying to load the preprocessed entity.
     52       InvalidKind,
     53 
     54       /// \brief A macro expansion.
     55       MacroExpansionKind,
     56 
     57       /// \defgroup Preprocessing directives
     58       /// @{
     59 
     60       /// \brief A macro definition.
     61       MacroDefinitionKind,
     62 
     63       /// \brief An inclusion directive, such as \c \#include, \c
     64       /// \#import, or \c \#include_next.
     65       InclusionDirectiveKind,
     66 
     67       /// @}
     68 
     69       FirstPreprocessingDirective = MacroDefinitionKind,
     70       LastPreprocessingDirective = InclusionDirectiveKind
     71     };
     72 
     73   private:
     74     /// \brief The kind of preprocessed entity that this object describes.
     75     EntityKind Kind;
     76 
     77     /// \brief The source range that covers this preprocessed entity.
     78     SourceRange Range;
     79 
     80   protected:
     81     PreprocessedEntity(EntityKind Kind, SourceRange Range)
     82       : Kind(Kind), Range(Range) { }
     83 
     84     friend class PreprocessingRecord;
     85 
     86   public:
     87     /// \brief Retrieve the kind of preprocessed entity stored in this object.
     88     EntityKind getKind() const { return Kind; }
     89 
     90     /// \brief Retrieve the source range that covers this entire preprocessed
     91     /// entity.
     92     SourceRange getSourceRange() const LLVM_READONLY { return Range; }
     93 
     94     /// \brief Returns true if there was a problem loading the preprocessed
     95     /// entity.
     96     bool isInvalid() const { return Kind == InvalidKind; }
     97 
     98     // Only allow allocation of preprocessed entities using the allocator
     99     // in PreprocessingRecord or by doing a placement new.
    100     void* operator new(size_t bytes, PreprocessingRecord& PR,
    101                        unsigned alignment = 8) throw() {
    102       return ::operator new(bytes, PR, alignment);
    103     }
    104 
    105     void* operator new(size_t bytes, void* mem) throw() {
    106       return mem;
    107     }
    108 
    109     void operator delete(void* ptr, PreprocessingRecord& PR,
    110                          unsigned alignment) throw() {
    111       return ::operator delete(ptr, PR, alignment);
    112     }
    113 
    114     void operator delete(void*, std::size_t) throw() { }
    115     void operator delete(void*, void*) throw() { }
    116 
    117   private:
    118     // Make vanilla 'new' and 'delete' illegal for preprocessed entities.
    119     void* operator new(size_t bytes) throw();
    120     void operator delete(void* data) throw();
    121   };
    122 
    123   /// \brief Records the presence of a preprocessor directive.
    124   class PreprocessingDirective : public PreprocessedEntity {
    125   public:
    126     PreprocessingDirective(EntityKind Kind, SourceRange Range)
    127       : PreprocessedEntity(Kind, Range) { }
    128 
    129     // Implement isa/cast/dyncast/etc.
    130     static bool classof(const PreprocessedEntity *PD) {
    131       return PD->getKind() >= FirstPreprocessingDirective &&
    132              PD->getKind() <= LastPreprocessingDirective;
    133     }
    134   };
    135 
    136   /// \brief Record the location of a macro definition.
    137   class MacroDefinition : public PreprocessingDirective {
    138     /// \brief The name of the macro being defined.
    139     const IdentifierInfo *Name;
    140 
    141   public:
    142     explicit MacroDefinition(const IdentifierInfo *Name, SourceRange Range)
    143       : PreprocessingDirective(MacroDefinitionKind, Range), Name(Name) { }
    144 
    145     /// \brief Retrieve the name of the macro being defined.
    146     const IdentifierInfo *getName() const { return Name; }
    147 
    148     /// \brief Retrieve the location of the macro name in the definition.
    149     SourceLocation getLocation() const { return getSourceRange().getBegin(); }
    150 
    151     // Implement isa/cast/dyncast/etc.
    152     static bool classof(const PreprocessedEntity *PE) {
    153       return PE->getKind() == MacroDefinitionKind;
    154     }
    155   };
    156 
    157   /// \brief Records the location of a macro expansion.
    158   class MacroExpansion : public PreprocessedEntity {
    159     /// \brief The definition of this macro or the name of the macro if it is
    160     /// a builtin macro.
    161     llvm::PointerUnion<IdentifierInfo *, MacroDefinition *> NameOrDef;
    162 
    163   public:
    164     MacroExpansion(IdentifierInfo *BuiltinName, SourceRange Range)
    165       : PreprocessedEntity(MacroExpansionKind, Range),
    166         NameOrDef(BuiltinName) { }
    167 
    168     MacroExpansion(MacroDefinition *Definition, SourceRange Range)
    169       : PreprocessedEntity(MacroExpansionKind, Range),
    170         NameOrDef(Definition) { }
    171 
    172     /// \brief True if it is a builtin macro.
    173     bool isBuiltinMacro() const { return NameOrDef.is<IdentifierInfo *>(); }
    174 
    175     /// \brief The name of the macro being expanded.
    176     const IdentifierInfo *getName() const {
    177       if (MacroDefinition *Def = getDefinition())
    178         return Def->getName();
    179       return NameOrDef.get<IdentifierInfo*>();
    180     }
    181 
    182     /// \brief The definition of the macro being expanded. May return null if
    183     /// this is a builtin macro.
    184     MacroDefinition *getDefinition() const {
    185       return NameOrDef.dyn_cast<MacroDefinition *>();
    186     }
    187 
    188     // Implement isa/cast/dyncast/etc.
    189     static bool classof(const PreprocessedEntity *PE) {
    190       return PE->getKind() == MacroExpansionKind;
    191     }
    192   };
    193 
    194   /// \brief Record the location of an inclusion directive, such as an
    195   /// \c \#include or \c \#import statement.
    196   class InclusionDirective : public PreprocessingDirective {
    197   public:
    198     /// \brief The kind of inclusion directives known to the
    199     /// preprocessor.
    200     enum InclusionKind {
    201       /// \brief An \c \#include directive.
    202       Include,
    203       /// \brief An Objective-C \c \#import directive.
    204       Import,
    205       /// \brief A GNU \c \#include_next directive.
    206       IncludeNext,
    207       /// \brief A Clang \c \#__include_macros directive.
    208       IncludeMacros
    209     };
    210 
    211   private:
    212     /// \brief The name of the file that was included, as written in
    213     /// the source.
    214     StringRef FileName;
    215 
    216     /// \brief Whether the file name was in quotation marks; otherwise, it was
    217     /// in angle brackets.
    218     unsigned InQuotes : 1;
    219 
    220     /// \brief The kind of inclusion directive we have.
    221     ///
    222     /// This is a value of type InclusionKind.
    223     unsigned Kind : 2;
    224 
    225     /// \brief Whether the inclusion directive was automatically turned into
    226     /// a module import.
    227     unsigned ImportedModule : 1;
    228 
    229     /// \brief The file that was included.
    230     const FileEntry *File;
    231 
    232   public:
    233     InclusionDirective(PreprocessingRecord &PPRec,
    234                        InclusionKind Kind, StringRef FileName,
    235                        bool InQuotes, bool ImportedModule,
    236                        const FileEntry *File, SourceRange Range);
    237 
    238     /// \brief Determine what kind of inclusion directive this is.
    239     InclusionKind getKind() const { return static_cast<InclusionKind>(Kind); }
    240 
    241     /// \brief Retrieve the included file name as it was written in the source.
    242     StringRef getFileName() const { return FileName; }
    243 
    244     /// \brief Determine whether the included file name was written in quotes;
    245     /// otherwise, it was written in angle brackets.
    246     bool wasInQuotes() const { return InQuotes; }
    247 
    248     /// \brief Determine whether the inclusion directive was automatically
    249     /// turned into a module import.
    250     bool importedModule() const { return ImportedModule; }
    251 
    252     /// \brief Retrieve the file entry for the actual file that was included
    253     /// by this directive.
    254     const FileEntry *getFile() const { return File; }
    255 
    256     // Implement isa/cast/dyncast/etc.
    257     static bool classof(const PreprocessedEntity *PE) {
    258       return PE->getKind() == InclusionDirectiveKind;
    259     }
    260   };
    261 
    262   /// \brief An abstract class that should be subclassed by any external source
    263   /// of preprocessing record entries.
    264   class ExternalPreprocessingRecordSource {
    265   public:
    266     virtual ~ExternalPreprocessingRecordSource();
    267 
    268     /// \brief Read a preallocated preprocessed entity from the external source.
    269     ///
    270     /// \returns null if an error occurred that prevented the preprocessed
    271     /// entity from being loaded.
    272     virtual PreprocessedEntity *ReadPreprocessedEntity(unsigned Index) = 0;
    273 
    274     /// \brief Returns a pair of [Begin, End) indices of preallocated
    275     /// preprocessed entities that \p Range encompasses.
    276     virtual std::pair<unsigned, unsigned>
    277         findPreprocessedEntitiesInRange(SourceRange Range) = 0;
    278 
    279     /// \brief Optionally returns true or false if the preallocated preprocessed
    280     /// entity with index \p Index came from file \p FID.
    281     virtual Optional<bool> isPreprocessedEntityInFileID(unsigned Index,
    282                                                         FileID FID) {
    283       return None;
    284     }
    285   };
    286 
    287   /// \brief A record of the steps taken while preprocessing a source file,
    288   /// including the various preprocessing directives processed, macros
    289   /// expanded, etc.
    290   class PreprocessingRecord : public PPCallbacks {
    291     SourceManager &SourceMgr;
    292 
    293     /// \brief Allocator used to store preprocessing objects.
    294     llvm::BumpPtrAllocator BumpAlloc;
    295 
    296     /// \brief The set of preprocessed entities in this record, in order they
    297     /// were seen.
    298     std::vector<PreprocessedEntity *> PreprocessedEntities;
    299 
    300     /// \brief The set of preprocessed entities in this record that have been
    301     /// loaded from external sources.
    302     ///
    303     /// The entries in this vector are loaded lazily from the external source,
    304     /// and are referenced by the iterator using negative indices.
    305     std::vector<PreprocessedEntity *> LoadedPreprocessedEntities;
    306 
    307     /// \brief The set of ranges that were skipped by the preprocessor,
    308     std::vector<SourceRange> SkippedRanges;
    309 
    310     /// \brief Global (loaded or local) ID for a preprocessed entity.
    311     /// Negative values are used to indicate preprocessed entities
    312     /// loaded from the external source while non-negative values are used to
    313     /// indicate preprocessed entities introduced by the current preprocessor.
    314     /// Value -1 corresponds to element 0 in the loaded entities vector,
    315     /// value -2 corresponds to element 1 in the loaded entities vector, etc.
    316     /// Value 0 is an invalid value, the index to local entities is 1-based,
    317     /// value 1 corresponds to element 0 in the local entities vector,
    318     /// value 2 corresponds to element 1 in the local entities vector, etc.
    319     class PPEntityID {
    320       int ID;
    321       explicit PPEntityID(int ID) : ID(ID) {}
    322       friend class PreprocessingRecord;
    323     public:
    324       PPEntityID() : ID(0) {}
    325     };
    326 
    327     static PPEntityID getPPEntityID(unsigned Index, bool isLoaded) {
    328       return isLoaded ? PPEntityID(-int(Index)-1) : PPEntityID(Index+1);
    329     }
    330 
    331     /// \brief Mapping from MacroInfo structures to their definitions.
    332     llvm::DenseMap<const MacroInfo *, MacroDefinition *> MacroDefinitions;
    333 
    334     /// \brief External source of preprocessed entities.
    335     ExternalPreprocessingRecordSource *ExternalSource;
    336 
    337     /// \brief Retrieve the preprocessed entity at the given ID.
    338     PreprocessedEntity *getPreprocessedEntity(PPEntityID PPID);
    339 
    340     /// \brief Retrieve the loaded preprocessed entity at the given index.
    341     PreprocessedEntity *getLoadedPreprocessedEntity(unsigned Index);
    342 
    343     /// \brief Determine the number of preprocessed entities that were
    344     /// loaded (or can be loaded) from an external source.
    345     unsigned getNumLoadedPreprocessedEntities() const {
    346       return LoadedPreprocessedEntities.size();
    347     }
    348 
    349     /// \brief Returns a pair of [Begin, End) indices of local preprocessed
    350     /// entities that \p Range encompasses.
    351     std::pair<unsigned, unsigned>
    352       findLocalPreprocessedEntitiesInRange(SourceRange Range) const;
    353     unsigned findBeginLocalPreprocessedEntity(SourceLocation Loc) const;
    354     unsigned findEndLocalPreprocessedEntity(SourceLocation Loc) const;
    355 
    356     /// \brief Allocate space for a new set of loaded preprocessed entities.
    357     ///
    358     /// \returns The index into the set of loaded preprocessed entities, which
    359     /// corresponds to the first newly-allocated entity.
    360     unsigned allocateLoadedEntities(unsigned NumEntities);
    361 
    362     /// \brief Register a new macro definition.
    363     void RegisterMacroDefinition(MacroInfo *Macro, MacroDefinition *Def);
    364 
    365   public:
    366     /// \brief Construct a new preprocessing record.
    367     explicit PreprocessingRecord(SourceManager &SM);
    368 
    369     /// \brief Allocate memory in the preprocessing record.
    370     void *Allocate(unsigned Size, unsigned Align = 8) {
    371       return BumpAlloc.Allocate(Size, Align);
    372     }
    373 
    374     /// \brief Deallocate memory in the preprocessing record.
    375     void Deallocate(void *Ptr) { }
    376 
    377     size_t getTotalMemory() const;
    378 
    379     SourceManager &getSourceManager() const { return SourceMgr; }
    380 
    381     // Iteration over the preprocessed entities.
    382     class iterator {
    383       PreprocessingRecord *Self;
    384 
    385       /// \brief Position within the preprocessed entity sequence.
    386       ///
    387       /// In a complete iteration, the Position field walks the range [-M, N),
    388       /// where negative values are used to indicate preprocessed entities
    389       /// loaded from the external source while non-negative values are used to
    390       /// indicate preprocessed entities introduced by the current preprocessor.
    391       /// However, to provide iteration in source order (for, e.g., chained
    392       /// precompiled headers), dereferencing the iterator flips the negative
    393       /// values (corresponding to loaded entities), so that position -M
    394       /// corresponds to element 0 in the loaded entities vector, position -M+1
    395       /// corresponds to element 1 in the loaded entities vector, etc. This
    396       /// gives us a reasonably efficient, source-order walk.
    397       int Position;
    398 
    399     public:
    400       typedef PreprocessedEntity *value_type;
    401       typedef value_type&         reference;
    402       typedef value_type*         pointer;
    403       typedef std::random_access_iterator_tag iterator_category;
    404       typedef int                 difference_type;
    405 
    406       iterator() : Self(nullptr), Position(0) { }
    407 
    408       iterator(PreprocessingRecord *Self, int Position)
    409         : Self(Self), Position(Position) { }
    410 
    411       value_type operator*() const {
    412         bool isLoaded = Position < 0;
    413         unsigned Index = isLoaded ?
    414             Self->LoadedPreprocessedEntities.size() + Position : Position;
    415         PPEntityID ID = Self->getPPEntityID(Index, isLoaded);
    416         return Self->getPreprocessedEntity(ID);
    417       }
    418 
    419       value_type operator[](difference_type D) {
    420         return *(*this + D);
    421       }
    422 
    423       iterator &operator++() {
    424         ++Position;
    425         return *this;
    426       }
    427 
    428       iterator operator++(int) {
    429         iterator Prev(*this);
    430         ++Position;
    431         return Prev;
    432       }
    433 
    434       iterator &operator--() {
    435         --Position;
    436         return *this;
    437       }
    438 
    439       iterator operator--(int) {
    440         iterator Prev(*this);
    441         --Position;
    442         return Prev;
    443       }
    444 
    445       friend bool operator==(const iterator &X, const iterator &Y) {
    446         return X.Position == Y.Position;
    447       }
    448 
    449       friend bool operator!=(const iterator &X, const iterator &Y) {
    450         return X.Position != Y.Position;
    451       }
    452 
    453       friend bool operator<(const iterator &X, const iterator &Y) {
    454         return X.Position < Y.Position;
    455       }
    456 
    457       friend bool operator>(const iterator &X, const iterator &Y) {
    458         return X.Position > Y.Position;
    459       }
    460 
    461       friend bool operator<=(const iterator &X, const iterator &Y) {
    462         return X.Position < Y.Position;
    463       }
    464 
    465       friend bool operator>=(const iterator &X, const iterator &Y) {
    466         return X.Position > Y.Position;
    467       }
    468 
    469       friend iterator& operator+=(iterator &X, difference_type D) {
    470         X.Position += D;
    471         return X;
    472       }
    473 
    474       friend iterator& operator-=(iterator &X, difference_type D) {
    475         X.Position -= D;
    476         return X;
    477       }
    478 
    479       friend iterator operator+(iterator X, difference_type D) {
    480         X.Position += D;
    481         return X;
    482       }
    483 
    484       friend iterator operator+(difference_type D, iterator X) {
    485         X.Position += D;
    486         return X;
    487       }
    488 
    489       friend difference_type operator-(const iterator &X, const iterator &Y) {
    490         return X.Position - Y.Position;
    491       }
    492 
    493       friend iterator operator-(iterator X, difference_type D) {
    494         X.Position -= D;
    495         return X;
    496       }
    497       friend class PreprocessingRecord;
    498     };
    499     friend class iterator;
    500 
    501     /// \brief Begin iterator for all preprocessed entities.
    502     iterator begin() {
    503       return iterator(this, -(int)LoadedPreprocessedEntities.size());
    504     }
    505 
    506     /// \brief End iterator for all preprocessed entities.
    507     iterator end() {
    508       return iterator(this, PreprocessedEntities.size());
    509     }
    510 
    511     /// \brief Begin iterator for local, non-loaded, preprocessed entities.
    512     iterator local_begin() {
    513       return iterator(this, 0);
    514     }
    515 
    516     /// \brief End iterator for local, non-loaded, preprocessed entities.
    517     iterator local_end() {
    518       return iterator(this, PreprocessedEntities.size());
    519     }
    520 
    521     /// \brief begin/end iterator pair for the given range of loaded
    522     /// preprocessed entities.
    523     std::pair<iterator, iterator>
    524     getIteratorsForLoadedRange(unsigned start, unsigned count) {
    525       unsigned end = start + count;
    526       assert(end <= LoadedPreprocessedEntities.size());
    527       return std::make_pair(
    528                    iterator(this, int(start)-LoadedPreprocessedEntities.size()),
    529                    iterator(this, int(end)-LoadedPreprocessedEntities.size()));
    530     }
    531 
    532     /// \brief Returns a pair of [Begin, End) iterators of preprocessed entities
    533     /// that source range \p R encompasses.
    534     ///
    535     /// \param R the range to look for preprocessed entities.
    536     ///
    537     std::pair<iterator, iterator> getPreprocessedEntitiesInRange(SourceRange R);
    538 
    539     /// \brief Returns true if the preprocessed entity that \p PPEI iterator
    540     /// points to is coming from the file \p FID.
    541     ///
    542     /// Can be used to avoid implicit deserializations of preallocated
    543     /// preprocessed entities if we only care about entities of a specific file
    544     /// and not from files \#included in the range given at
    545     /// \see getPreprocessedEntitiesInRange.
    546     bool isEntityInFileID(iterator PPEI, FileID FID);
    547 
    548     /// \brief Add a new preprocessed entity to this record.
    549     PPEntityID addPreprocessedEntity(PreprocessedEntity *Entity);
    550 
    551     /// \brief Set the external source for preprocessed entities.
    552     void SetExternalSource(ExternalPreprocessingRecordSource &Source);
    553 
    554     /// \brief Retrieve the external source for preprocessed entities.
    555     ExternalPreprocessingRecordSource *getExternalSource() const {
    556       return ExternalSource;
    557     }
    558 
    559     /// \brief Retrieve the macro definition that corresponds to the given
    560     /// \c MacroInfo.
    561     MacroDefinition *findMacroDefinition(const MacroInfo *MI);
    562 
    563     /// \brief Retrieve all ranges that got skipped while preprocessing.
    564     const std::vector<SourceRange> &getSkippedRanges() const {
    565       return SkippedRanges;
    566     }
    567 
    568   private:
    569     void MacroExpands(const Token &Id, const MacroDirective *MD,
    570                       SourceRange Range, const MacroArgs *Args) override;
    571     void MacroDefined(const Token &Id, const MacroDirective *MD) override;
    572     void MacroUndefined(const Token &Id, const MacroDirective *MD) override;
    573     void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
    574                             StringRef FileName, bool IsAngled,
    575                             CharSourceRange FilenameRange,
    576                             const FileEntry *File, StringRef SearchPath,
    577                             StringRef RelativePath,
    578                             const Module *Imported) override;
    579     void Ifdef(SourceLocation Loc, const Token &MacroNameTok,
    580                const MacroDirective *MD) override;
    581     void Ifndef(SourceLocation Loc, const Token &MacroNameTok,
    582                 const MacroDirective *MD) override;
    583     /// \brief Hook called whenever the 'defined' operator is seen.
    584     void Defined(const Token &MacroNameTok, const MacroDirective *MD,
    585                  SourceRange Range) override;
    586 
    587     void SourceRangeSkipped(SourceRange Range) override;
    588 
    589     void addMacroExpansion(const Token &Id, const MacroInfo *MI,
    590                            SourceRange Range);
    591 
    592     /// \brief Cached result of the last \see getPreprocessedEntitiesInRange
    593     /// query.
    594     struct {
    595       SourceRange Range;
    596       std::pair<int, int> Result;
    597     } CachedRangeQuery;
    598 
    599     std::pair<int, int> getPreprocessedEntitiesInRangeSlow(SourceRange R);
    600 
    601     friend class ASTReader;
    602     friend class ASTWriter;
    603   };
    604 } // end namespace clang
    605 
    606 inline void* operator new(size_t bytes, clang::PreprocessingRecord& PR,
    607                           unsigned alignment) throw() {
    608   return PR.Allocate(bytes, alignment);
    609 }
    610 
    611 inline void operator delete(void* ptr, clang::PreprocessingRecord& PR,
    612                             unsigned) throw() {
    613   PR.Deallocate(ptr);
    614 }
    615 
    616 #endif // LLVM_CLANG_LEX_PREPROCESSINGRECORD_H
    617