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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() || Var->isInline()) &&
     77       !(Var->isStaticDataMember() && Var->hasInit())) {
     78     SourceLocation &old = SemaRef.UndefinedButUsed[Var->getCanonicalDecl()];
     79     if (old.isInvalid())
     80       old = Loc;
     81   }
     82   QualType CaptureType, DeclRefType;
     83   SemaRef.tryCaptureVariable(Var, Loc, Sema::TryCapture_Implicit,
     84     /*EllipsisLoc*/ SourceLocation(),
     85     /*BuildAndDiagnose*/ true,
     86     CaptureType, DeclRefType,
     87     FunctionScopeIndexToStopAt);
     88 
     89   Var->markUsed(SemaRef.Context);
     90 }
     91 
     92 /// Return a DLL attribute from the declaration.
     93 inline InheritableAttr *getDLLAttr(Decl *D) {
     94   assert(!(D->hasAttr<DLLImportAttr>() && D->hasAttr<DLLExportAttr>()) &&
     95          "A declaration cannot be both dllimport and dllexport.");
     96   if (auto *Import = D->getAttr<DLLImportAttr>())
     97     return Import;
     98   if (auto *Export = D->getAttr<DLLExportAttr>())
     99     return Export;
    100   return nullptr;
    101 }
    102 
    103 class TypoCorrectionConsumer : public VisibleDeclConsumer {
    104   typedef SmallVector<TypoCorrection, 1> TypoResultList;
    105   typedef llvm::StringMap<TypoResultList> TypoResultsMap;
    106   typedef std::map<unsigned, TypoResultsMap> TypoEditDistanceMap;
    107 
    108 public:
    109   TypoCorrectionConsumer(Sema &SemaRef,
    110                          const DeclarationNameInfo &TypoName,
    111                          Sema::LookupNameKind LookupKind,
    112                          Scope *S, CXXScopeSpec *SS,
    113                          std::unique_ptr<CorrectionCandidateCallback> CCC,
    114                          DeclContext *MemberContext,
    115                          bool EnteringContext)
    116       : Typo(TypoName.getName().getAsIdentifierInfo()), CurrentTCIndex(0),
    117         SavedTCIndex(0), SemaRef(SemaRef), S(S),
    118         SS(SS ? llvm::make_unique<CXXScopeSpec>(*SS) : nullptr),
    119         CorrectionValidator(std::move(CCC)), MemberContext(MemberContext),
    120         Result(SemaRef, TypoName, LookupKind),
    121         Namespaces(SemaRef.Context, SemaRef.CurContext, SS),
    122         EnteringContext(EnteringContext), SearchNamespaces(false) {
    123     Result.suppressDiagnostics();
    124     // Arrange for ValidatedCorrections[0] to always be an empty correction.
    125     ValidatedCorrections.push_back(TypoCorrection());
    126   }
    127 
    128   bool includeHiddenDecls() const override { return true; }
    129 
    130   // Methods for adding potential corrections to the consumer.
    131   void FoundDecl(NamedDecl *ND, NamedDecl *Hiding, DeclContext *Ctx,
    132                  bool InBaseClass) override;
    133   void FoundName(StringRef Name);
    134   void addKeywordResult(StringRef Keyword);
    135   void addCorrection(TypoCorrection Correction);
    136 
    137   bool empty() const {
    138     return CorrectionResults.empty() && ValidatedCorrections.size() == 1;
    139   }
    140 
    141   /// \brief Return the list of TypoCorrections for the given identifier from
    142   /// the set of corrections that have the closest edit distance, if any.
    143   TypoResultList &operator[](StringRef Name) {
    144     return CorrectionResults.begin()->second[Name];
    145   }
    146 
    147   /// \brief Return the edit distance of the corrections that have the
    148   /// closest/best edit distance from the original typop.
    149   unsigned getBestEditDistance(bool Normalized) {
    150     if (CorrectionResults.empty())
    151       return (std::numeric_limits<unsigned>::max)();
    152 
    153     unsigned BestED = CorrectionResults.begin()->first;
    154     return Normalized ? TypoCorrection::NormalizeEditDistance(BestED) : BestED;
    155   }
    156 
    157   /// \brief Set-up method to add to the consumer the set of namespaces to use
    158   /// in performing corrections to nested name specifiers. This method also
    159   /// implicitly adds all of the known classes in the current AST context to the
    160   /// to the consumer for correcting nested name specifiers.
    161   void
    162   addNamespaces(const llvm::MapVector<NamespaceDecl *, bool> &KnownNamespaces);
    163 
    164   /// \brief Return the next typo correction that passes all internal filters
    165   /// and is deemed valid by the consumer's CorrectionCandidateCallback,
    166   /// starting with the corrections that have the closest edit distance. An
    167   /// empty TypoCorrection is returned once no more viable corrections remain
    168   /// in the consumer.
    169   const TypoCorrection &getNextCorrection();
    170 
    171   /// \brief Get the last correction returned by getNextCorrection().
    172   const TypoCorrection &getCurrentCorrection() {
    173     return CurrentTCIndex < ValidatedCorrections.size()
    174                ? ValidatedCorrections[CurrentTCIndex]
    175                : ValidatedCorrections[0];  // The empty correction.
    176   }
    177 
    178   /// \brief Return the next typo correction like getNextCorrection, but keep
    179   /// the internal state pointed to the current correction (i.e. the next time
    180   /// getNextCorrection is called, it will return the same correction returned
    181   /// by peekNextcorrection).
    182   const TypoCorrection &peekNextCorrection() {
    183     auto Current = CurrentTCIndex;
    184     const TypoCorrection &TC = getNextCorrection();
    185     CurrentTCIndex = Current;
    186     return TC;
    187   }
    188 
    189   /// \brief Reset the consumer's position in the stream of viable corrections
    190   /// (i.e. getNextCorrection() will return each of the previously returned
    191   /// corrections in order before returning any new corrections).
    192   void resetCorrectionStream() {
    193     CurrentTCIndex = 0;
    194   }
    195 
    196   /// \brief Return whether the end of the stream of corrections has been
    197   /// reached.
    198   bool finished() {
    199     return CorrectionResults.empty() &&
    200            CurrentTCIndex >= ValidatedCorrections.size();
    201   }
    202 
    203   /// \brief Save the current position in the correction stream (overwriting any
    204   /// previously saved position).
    205   void saveCurrentPosition() {
    206     SavedTCIndex = CurrentTCIndex;
    207   }
    208 
    209   /// \brief Restore the saved position in the correction stream.
    210   void restoreSavedPosition() {
    211     CurrentTCIndex = SavedTCIndex;
    212   }
    213 
    214   ASTContext &getContext() const { return SemaRef.Context; }
    215   const LookupResult &getLookupResult() const { return Result; }
    216 
    217   bool isAddressOfOperand() const { return CorrectionValidator->IsAddressOfOperand; }
    218   const CXXScopeSpec *getSS() const { return SS.get(); }
    219   Scope *getScope() const { return S; }
    220   CorrectionCandidateCallback *getCorrectionValidator() const {
    221     return CorrectionValidator.get();
    222   }
    223 
    224 private:
    225   class NamespaceSpecifierSet {
    226     struct SpecifierInfo {
    227       DeclContext* DeclCtx;
    228       NestedNameSpecifier* NameSpecifier;
    229       unsigned EditDistance;
    230     };
    231 
    232     typedef SmallVector<DeclContext*, 4> DeclContextList;
    233     typedef SmallVector<SpecifierInfo, 16> SpecifierInfoList;
    234 
    235     ASTContext &Context;
    236     DeclContextList CurContextChain;
    237     std::string CurNameSpecifier;
    238     SmallVector<const IdentifierInfo*, 4> CurContextIdentifiers;
    239     SmallVector<const IdentifierInfo*, 4> CurNameSpecifierIdentifiers;
    240 
    241     std::map<unsigned, SpecifierInfoList> DistanceMap;
    242 
    243     /// \brief Helper for building the list of DeclContexts between the current
    244     /// context and the top of the translation unit
    245     static DeclContextList buildContextChain(DeclContext *Start);
    246 
    247     unsigned buildNestedNameSpecifier(DeclContextList &DeclChain,
    248                                       NestedNameSpecifier *&NNS);
    249 
    250    public:
    251     NamespaceSpecifierSet(ASTContext &Context, DeclContext *CurContext,
    252                           CXXScopeSpec *CurScopeSpec);
    253 
    254     /// \brief Add the DeclContext (a namespace or record) to the set, computing
    255     /// the corresponding NestedNameSpecifier and its distance in the process.
    256     void addNameSpecifier(DeclContext *Ctx);
    257 
    258     /// \brief Provides flat iteration over specifiers, sorted by distance.
    259     class iterator
    260         : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
    261                                             SpecifierInfo> {
    262       /// Always points to the last element in the distance map.
    263       const std::map<unsigned, SpecifierInfoList>::iterator OuterBack;
    264       /// Iterator on the distance map.
    265       std::map<unsigned, SpecifierInfoList>::iterator Outer;
    266       /// Iterator on an element in the distance map.
    267       SpecifierInfoList::iterator Inner;
    268 
    269     public:
    270       iterator(NamespaceSpecifierSet &Set, bool IsAtEnd)
    271           : OuterBack(std::prev(Set.DistanceMap.end())),
    272             Outer(Set.DistanceMap.begin()),
    273             Inner(!IsAtEnd ? Outer->second.begin() : OuterBack->second.end()) {
    274         assert(!Set.DistanceMap.empty());
    275       }
    276 
    277       iterator &operator++() {
    278         ++Inner;
    279         if (Inner == Outer->second.end() && Outer != OuterBack) {
    280           ++Outer;
    281           Inner = Outer->second.begin();
    282         }
    283         return *this;
    284       }
    285 
    286       SpecifierInfo &operator*() { return *Inner; }
    287       bool operator==(const iterator &RHS) const { return Inner == RHS.Inner; }
    288     };
    289 
    290     iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
    291     iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
    292   };
    293 
    294   void addName(StringRef Name, NamedDecl *ND,
    295                NestedNameSpecifier *NNS = nullptr, bool isKeyword = false);
    296 
    297   /// \brief Find any visible decls for the given typo correction candidate.
    298   /// If none are found, it to the set of candidates for which qualified lookups
    299   /// will be performed to find possible nested name specifier changes.
    300   bool resolveCorrection(TypoCorrection &Candidate);
    301 
    302   /// \brief Perform qualified lookups on the queued set of typo correction
    303   /// candidates and add the nested name specifier changes to each candidate if
    304   /// a lookup succeeds (at which point the candidate will be returned to the
    305   /// main pool of potential corrections).
    306   void performQualifiedLookups();
    307 
    308   /// \brief The name written that is a typo in the source.
    309   IdentifierInfo *Typo;
    310 
    311   /// \brief The results found that have the smallest edit distance
    312   /// found (so far) with the typo name.
    313   ///
    314   /// The pointer value being set to the current DeclContext indicates
    315   /// whether there is a keyword with this name.
    316   TypoEditDistanceMap CorrectionResults;
    317 
    318   SmallVector<TypoCorrection, 4> ValidatedCorrections;
    319   size_t CurrentTCIndex;
    320   size_t SavedTCIndex;
    321 
    322   Sema &SemaRef;
    323   Scope *S;
    324   std::unique_ptr<CXXScopeSpec> SS;
    325   std::unique_ptr<CorrectionCandidateCallback> CorrectionValidator;
    326   DeclContext *MemberContext;
    327   LookupResult Result;
    328   NamespaceSpecifierSet Namespaces;
    329   SmallVector<TypoCorrection, 2> QualifiedResults;
    330   bool EnteringContext;
    331   bool SearchNamespaces;
    332 };
    333 
    334 inline Sema::TypoExprState::TypoExprState() {}
    335 
    336 inline Sema::TypoExprState::TypoExprState(TypoExprState &&other) noexcept {
    337   *this = std::move(other);
    338 }
    339 
    340 inline Sema::TypoExprState &Sema::TypoExprState::
    341 operator=(Sema::TypoExprState &&other) noexcept {
    342   Consumer = std::move(other.Consumer);
    343   DiagHandler = std::move(other.DiagHandler);
    344   RecoveryHandler = std::move(other.RecoveryHandler);
    345   return *this;
    346 }
    347 
    348 } // end namespace clang
    349 
    350 #endif
    351