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