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      1 //===--- SemaInternal.h - Internal Sema Interfaces --------------*- 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 provides common API and #includes for the internal
     11 // implementation of Sema.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_CLANG_SEMA_SEMAINTERNAL_H
     16 #define LLVM_CLANG_SEMA_SEMAINTERNAL_H
     17 
     18 #include "clang/AST/ASTContext.h"
     19 #include "clang/Sema/Lookup.h"
     20 #include "clang/Sema/Sema.h"
     21 #include "clang/Sema/SemaDiagnostic.h"
     22 
     23 namespace clang {
     24 
     25 inline PartialDiagnostic Sema::PDiag(unsigned DiagID) {
     26   return PartialDiagnostic(DiagID, Context.getDiagAllocator());
     27 }
     28 
     29 inline bool
     30 FTIHasSingleVoidParameter(const DeclaratorChunk::FunctionTypeInfo &FTI) {
     31   return FTI.NumParams == 1 && !FTI.isVariadic &&
     32          FTI.Params[0].Ident == nullptr && FTI.Params[0].Param &&
     33          cast<ParmVarDecl>(FTI.Params[0].Param)->getType()->isVoidType();
     34 }
     35 
     36 inline bool
     37 FTIHasNonVoidParameters(const DeclaratorChunk::FunctionTypeInfo &FTI) {
     38   // Assume FTI is well-formed.
     39   return FTI.NumParams && !FTIHasSingleVoidParameter(FTI);
     40 }
     41 
     42 // This requires the variable to be non-dependent and the initializer
     43 // to not be value dependent.
     44 inline bool IsVariableAConstantExpression(VarDecl *Var, ASTContext &Context) {
     45   const VarDecl *DefVD = nullptr;
     46   return !isa<ParmVarDecl>(Var) &&
     47     Var->isUsableInConstantExpressions(Context) &&
     48     Var->getAnyInitializer(DefVD) && DefVD->checkInitIsICE();
     49 }
     50 
     51 // Helper function to check whether D's attributes match current CUDA mode.
     52 // Decls with mismatched attributes and related diagnostics may have to be
     53 // ignored during this CUDA compilation pass.
     54 inline bool DeclAttrsMatchCUDAMode(const LangOptions &LangOpts, Decl *D) {
     55   if (!LangOpts.CUDA || !D)
     56     return true;
     57   bool isDeviceSideDecl = D->hasAttr<CUDADeviceAttr>() ||
     58                           D->hasAttr<CUDASharedAttr>() ||
     59                           D->hasAttr<CUDAGlobalAttr>();
     60   return isDeviceSideDecl == LangOpts.CUDAIsDevice;
     61 }
     62 
     63 // Directly mark a variable odr-used. Given a choice, prefer to use
     64 // MarkVariableReferenced since it does additional checks and then
     65 // calls MarkVarDeclODRUsed.
     66 // If the variable must be captured:
     67 //  - if FunctionScopeIndexToStopAt is null, capture it in the CurContext
     68 //  - else capture it in the DeclContext that maps to the
     69 //    *FunctionScopeIndexToStopAt on the FunctionScopeInfo stack.
     70 inline void MarkVarDeclODRUsed(VarDecl *Var,
     71     SourceLocation Loc, Sema &SemaRef,
     72     const unsigned *const FunctionScopeIndexToStopAt) {
     73   // Keep track of used but undefined variables.
     74   // FIXME: We shouldn't suppress this warning for static data members.
     75   if (Var->hasDefinition(SemaRef.Context) == VarDecl::DeclarationOnly &&
     76     !Var->isExternallyVisible() &&
     77     !(Var->isStaticDataMember() && Var->hasInit())) {
     78       SourceLocation &old = SemaRef.UndefinedButUsed[Var->getCanonicalDecl()];
     79       if (old.isInvalid()) old = Loc;
     80   }
     81   QualType CaptureType, DeclRefType;
     82   SemaRef.tryCaptureVariable(Var, Loc, Sema::TryCapture_Implicit,
     83     /*EllipsisLoc*/ SourceLocation(),
     84     /*BuildAndDiagnose*/ true,
     85     CaptureType, DeclRefType,
     86     FunctionScopeIndexToStopAt);
     87 
     88   Var->markUsed(SemaRef.Context);
     89 }
     90 
     91 /// Return a DLL attribute from the declaration.
     92 inline InheritableAttr *getDLLAttr(Decl *D) {
     93   assert(!(D->hasAttr<DLLImportAttr>() && D->hasAttr<DLLExportAttr>()) &&
     94          "A declaration cannot be both dllimport and dllexport.");
     95   if (auto *Import = D->getAttr<DLLImportAttr>())
     96     return Import;
     97   if (auto *Export = D->getAttr<DLLExportAttr>())
     98     return Export;
     99   return nullptr;
    100 }
    101 
    102 class TypoCorrectionConsumer : public VisibleDeclConsumer {
    103   typedef SmallVector<TypoCorrection, 1> TypoResultList;
    104   typedef llvm::StringMap<TypoResultList> TypoResultsMap;
    105   typedef std::map<unsigned, TypoResultsMap> TypoEditDistanceMap;
    106 
    107 public:
    108   TypoCorrectionConsumer(Sema &SemaRef,
    109                          const DeclarationNameInfo &TypoName,
    110                          Sema::LookupNameKind LookupKind,
    111                          Scope *S, CXXScopeSpec *SS,
    112                          std::unique_ptr<CorrectionCandidateCallback> CCC,
    113                          DeclContext *MemberContext,
    114                          bool EnteringContext)
    115       : Typo(TypoName.getName().getAsIdentifierInfo()), CurrentTCIndex(0),
    116         SavedTCIndex(0), SemaRef(SemaRef), S(S),
    117         SS(SS ? llvm::make_unique<CXXScopeSpec>(*SS) : nullptr),
    118         CorrectionValidator(std::move(CCC)), MemberContext(MemberContext),
    119         Result(SemaRef, TypoName, LookupKind),
    120         Namespaces(SemaRef.Context, SemaRef.CurContext, SS),
    121         EnteringContext(EnteringContext), SearchNamespaces(false) {
    122     Result.suppressDiagnostics();
    123     // Arrange for ValidatedCorrections[0] to always be an empty correction.
    124     ValidatedCorrections.push_back(TypoCorrection());
    125   }
    126 
    127   bool includeHiddenDecls() const override { return true; }
    128 
    129   // Methods for adding potential corrections to the consumer.
    130   void FoundDecl(NamedDecl *ND, NamedDecl *Hiding, DeclContext *Ctx,
    131                  bool InBaseClass) override;
    132   void FoundName(StringRef Name);
    133   void addKeywordResult(StringRef Keyword);
    134   void addCorrection(TypoCorrection Correction);
    135 
    136   bool empty() const {
    137     return CorrectionResults.empty() && ValidatedCorrections.size() == 1;
    138   }
    139 
    140   /// \brief Return the list of TypoCorrections for the given identifier from
    141   /// the set of corrections that have the closest edit distance, if any.
    142   TypoResultList &operator[](StringRef Name) {
    143     return CorrectionResults.begin()->second[Name];
    144   }
    145 
    146   /// \brief Return the edit distance of the corrections that have the
    147   /// closest/best edit distance from the original typop.
    148   unsigned getBestEditDistance(bool Normalized) {
    149     if (CorrectionResults.empty())
    150       return (std::numeric_limits<unsigned>::max)();
    151 
    152     unsigned BestED = CorrectionResults.begin()->first;
    153     return Normalized ? TypoCorrection::NormalizeEditDistance(BestED) : BestED;
    154   }
    155 
    156   /// \brief Set-up method to add to the consumer the set of namespaces to use
    157   /// in performing corrections to nested name specifiers. This method also
    158   /// implicitly adds all of the known classes in the current AST context to the
    159   /// to the consumer for correcting nested name specifiers.
    160   void
    161   addNamespaces(const llvm::MapVector<NamespaceDecl *, bool> &KnownNamespaces);
    162 
    163   /// \brief Return the next typo correction that passes all internal filters
    164   /// and is deemed valid by the consumer's CorrectionCandidateCallback,
    165   /// starting with the corrections that have the closest edit distance. An
    166   /// empty TypoCorrection is returned once no more viable corrections remain
    167   /// in the consumer.
    168   const TypoCorrection &getNextCorrection();
    169 
    170   /// \brief Get the last correction returned by getNextCorrection().
    171   const TypoCorrection &getCurrentCorrection() {
    172     return CurrentTCIndex < ValidatedCorrections.size()
    173                ? ValidatedCorrections[CurrentTCIndex]
    174                : ValidatedCorrections[0];  // The empty correction.
    175   }
    176 
    177   /// \brief Return the next typo correction like getNextCorrection, but keep
    178   /// the internal state pointed to the current correction (i.e. the next time
    179   /// getNextCorrection is called, it will return the same correction returned
    180   /// by peekNextcorrection).
    181   const TypoCorrection &peekNextCorrection() {
    182     auto Current = CurrentTCIndex;
    183     const TypoCorrection &TC = getNextCorrection();
    184     CurrentTCIndex = Current;
    185     return TC;
    186   }
    187 
    188   /// \brief Reset the consumer's position in the stream of viable corrections
    189   /// (i.e. getNextCorrection() will return each of the previously returned
    190   /// corrections in order before returning any new corrections).
    191   void resetCorrectionStream() {
    192     CurrentTCIndex = 0;
    193   }
    194 
    195   /// \brief Return whether the end of the stream of corrections has been
    196   /// reached.
    197   bool finished() {
    198     return CorrectionResults.empty() &&
    199            CurrentTCIndex >= ValidatedCorrections.size();
    200   }
    201 
    202   /// \brief Save the current position in the correction stream (overwriting any
    203   /// previously saved position).
    204   void saveCurrentPosition() {
    205     SavedTCIndex = CurrentTCIndex;
    206   }
    207 
    208   /// \brief Restore the saved position in the correction stream.
    209   void restoreSavedPosition() {
    210     CurrentTCIndex = SavedTCIndex;
    211   }
    212 
    213   ASTContext &getContext() const { return SemaRef.Context; }
    214   const LookupResult &getLookupResult() const { return Result; }
    215 
    216   bool isAddressOfOperand() const { return CorrectionValidator->IsAddressOfOperand; }
    217   const CXXScopeSpec *getSS() const { return SS.get(); }
    218   Scope *getScope() const { return S; }
    219 
    220 private:
    221   class NamespaceSpecifierSet {
    222     struct SpecifierInfo {
    223       DeclContext* DeclCtx;
    224       NestedNameSpecifier* NameSpecifier;
    225       unsigned EditDistance;
    226     };
    227 
    228     typedef SmallVector<DeclContext*, 4> DeclContextList;
    229     typedef SmallVector<SpecifierInfo, 16> SpecifierInfoList;
    230 
    231     ASTContext &Context;
    232     DeclContextList CurContextChain;
    233     std::string CurNameSpecifier;
    234     SmallVector<const IdentifierInfo*, 4> CurContextIdentifiers;
    235     SmallVector<const IdentifierInfo*, 4> CurNameSpecifierIdentifiers;
    236 
    237     std::map<unsigned, SpecifierInfoList> DistanceMap;
    238 
    239     /// \brief Helper for building the list of DeclContexts between the current
    240     /// context and the top of the translation unit
    241     static DeclContextList buildContextChain(DeclContext *Start);
    242 
    243     unsigned buildNestedNameSpecifier(DeclContextList &DeclChain,
    244                                       NestedNameSpecifier *&NNS);
    245 
    246    public:
    247     NamespaceSpecifierSet(ASTContext &Context, DeclContext *CurContext,
    248                           CXXScopeSpec *CurScopeSpec);
    249 
    250     /// \brief Add the DeclContext (a namespace or record) to the set, computing
    251     /// the corresponding NestedNameSpecifier and its distance in the process.
    252     void addNameSpecifier(DeclContext *Ctx);
    253 
    254     /// \brief Provides flat iteration over specifiers, sorted by distance.
    255     class iterator
    256         : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
    257                                             SpecifierInfo> {
    258       /// Always points to the last element in the distance map.
    259       const std::map<unsigned, SpecifierInfoList>::iterator OuterBack;
    260       /// Iterator on the distance map.
    261       std::map<unsigned, SpecifierInfoList>::iterator Outer;
    262       /// Iterator on an element in the distance map.
    263       SpecifierInfoList::iterator Inner;
    264 
    265     public:
    266       iterator(NamespaceSpecifierSet &Set, bool IsAtEnd)
    267           : OuterBack(std::prev(Set.DistanceMap.end())),
    268             Outer(Set.DistanceMap.begin()),
    269             Inner(!IsAtEnd ? Outer->second.begin() : OuterBack->second.end()) {
    270         assert(!Set.DistanceMap.empty());
    271       }
    272 
    273       iterator &operator++() {
    274         ++Inner;
    275         if (Inner == Outer->second.end() && Outer != OuterBack) {
    276           ++Outer;
    277           Inner = Outer->second.begin();
    278         }
    279         return *this;
    280       }
    281 
    282       SpecifierInfo &operator*() { return *Inner; }
    283       bool operator==(const iterator &RHS) const { return Inner == RHS.Inner; }
    284     };
    285 
    286     iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
    287     iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
    288   };
    289 
    290   void addName(StringRef Name, NamedDecl *ND,
    291                NestedNameSpecifier *NNS = nullptr, bool isKeyword = false);
    292 
    293   /// \brief Find any visible decls for the given typo correction candidate.
    294   /// If none are found, it to the set of candidates for which qualified lookups
    295   /// will be performed to find possible nested name specifier changes.
    296   bool resolveCorrection(TypoCorrection &Candidate);
    297 
    298   /// \brief Perform qualified lookups on the queued set of typo correction
    299   /// candidates and add the nested name specifier changes to each candidate if
    300   /// a lookup succeeds (at which point the candidate will be returned to the
    301   /// main pool of potential corrections).
    302   void performQualifiedLookups();
    303 
    304   /// \brief The name written that is a typo in the source.
    305   IdentifierInfo *Typo;
    306 
    307   /// \brief The results found that have the smallest edit distance
    308   /// found (so far) with the typo name.
    309   ///
    310   /// The pointer value being set to the current DeclContext indicates
    311   /// whether there is a keyword with this name.
    312   TypoEditDistanceMap CorrectionResults;
    313 
    314   SmallVector<TypoCorrection, 4> ValidatedCorrections;
    315   size_t CurrentTCIndex;
    316   size_t SavedTCIndex;
    317 
    318   Sema &SemaRef;
    319   Scope *S;
    320   std::unique_ptr<CXXScopeSpec> SS;
    321   std::unique_ptr<CorrectionCandidateCallback> CorrectionValidator;
    322   DeclContext *MemberContext;
    323   LookupResult Result;
    324   NamespaceSpecifierSet Namespaces;
    325   SmallVector<TypoCorrection, 2> QualifiedResults;
    326   bool EnteringContext;
    327   bool SearchNamespaces;
    328 };
    329 
    330 inline Sema::TypoExprState::TypoExprState() {}
    331 
    332 inline Sema::TypoExprState::TypoExprState(TypoExprState &&other) LLVM_NOEXCEPT {
    333   *this = std::move(other);
    334 }
    335 
    336 inline Sema::TypoExprState &Sema::TypoExprState::operator=(
    337     Sema::TypoExprState &&other) LLVM_NOEXCEPT {
    338   Consumer = std::move(other.Consumer);
    339   DiagHandler = std::move(other.DiagHandler);
    340   RecoveryHandler = std::move(other.RecoveryHandler);
    341   return *this;
    342 }
    343 
    344 } // end namespace clang
    345 
    346 #endif
    347