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      1 //===--- ASTConsumer.h - Abstract interface for reading ASTs ----*- 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 ASTConsumer class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_AST_ASTCONSUMER_H
     15 #define LLVM_CLANG_AST_ASTCONSUMER_H
     16 
     17 namespace clang {
     18   class ASTContext;
     19   class CXXRecordDecl;
     20   class Decl;
     21   class DeclGroupRef;
     22   class HandleTagDeclDefinition;
     23   class PPMutationListener;
     24   class ASTMutationListener;
     25   class ASTDeserializationListener; // layering violation because void* is ugly
     26   class SemaConsumer; // layering violation required for safe SemaConsumer
     27   class TagDecl;
     28   class VarDecl;
     29   class FunctionDecl;
     30   class ImportDecl;
     31 
     32 /// ASTConsumer - This is an abstract interface that should be implemented by
     33 /// clients that read ASTs.  This abstraction layer allows the client to be
     34 /// independent of the AST producer (e.g. parser vs AST dump file reader, etc).
     35 class ASTConsumer {
     36   /// \brief Whether this AST consumer also requires information about
     37   /// semantic analysis.
     38   bool SemaConsumer;
     39 
     40   friend class SemaConsumer;
     41 
     42 public:
     43   ASTConsumer() : SemaConsumer(false) { }
     44 
     45   virtual ~ASTConsumer() {}
     46 
     47   /// Initialize - This is called to initialize the consumer, providing the
     48   /// ASTContext.
     49   virtual void Initialize(ASTContext &Context) {}
     50 
     51   /// HandleTopLevelDecl - Handle the specified top-level declaration.  This is
     52   /// called by the parser to process every top-level Decl*. Note that D can be
     53   /// the head of a chain of Decls (e.g. for `int a, b` the chain will have two
     54   /// elements). Use Decl::getNextDeclarator() to walk the chain.
     55   ///
     56   /// \returns true to continue parsing, or false to abort parsing.
     57   virtual bool HandleTopLevelDecl(DeclGroupRef D);
     58 
     59   /// HandleInterestingDecl - Handle the specified interesting declaration. This
     60   /// is called by the AST reader when deserializing things that might interest
     61   /// the consumer. The default implementation forwards to HandleTopLevelDecl.
     62   virtual void HandleInterestingDecl(DeclGroupRef D);
     63 
     64   /// HandleTranslationUnit - This method is called when the ASTs for entire
     65   /// translation unit have been parsed.
     66   virtual void HandleTranslationUnit(ASTContext &Ctx) {}
     67 
     68   /// HandleTagDeclDefinition - This callback is invoked each time a TagDecl
     69   /// (e.g. struct, union, enum, class) is completed.  This allows the client to
     70   /// hack on the type, which can occur at any point in the file (because these
     71   /// can be defined in declspecs).
     72   virtual void HandleTagDeclDefinition(TagDecl *D) {}
     73 
     74   /// \brief Invoked when a function is implicitly instantiated.
     75   /// Note that at this point point it does not have a body, its body is
     76   /// instantiated at the end of the translation unit and passed to
     77   /// HandleTopLevelDecl.
     78   virtual void HandleCXXImplicitFunctionInstantiation(FunctionDecl *D) {}
     79 
     80   /// \brief Handle the specified top-level declaration that occurred inside
     81   /// and ObjC container.
     82   /// The default implementation ignored them.
     83   virtual void HandleTopLevelDeclInObjCContainer(DeclGroupRef D);
     84 
     85   /// \brief Handle an ImportDecl that was implicitly created due to an
     86   /// inclusion directive.
     87   /// The default implementation passes it to HandleTopLevelDecl.
     88   virtual void HandleImplicitImportDecl(ImportDecl *D);
     89 
     90   /// CompleteTentativeDefinition - Callback invoked at the end of a translation
     91   /// unit to notify the consumer that the given tentative definition should be
     92   /// completed.
     93   ///
     94   /// The variable declaration itself will be a tentative
     95   /// definition. If it had an incomplete array type, its type will
     96   /// have already been changed to an array of size 1. However, the
     97   /// declaration remains a tentative definition and has not been
     98   /// modified by the introduction of an implicit zero initializer.
     99   virtual void CompleteTentativeDefinition(VarDecl *D) {}
    100 
    101   /// HandleCXXStaticMemberVarInstantiation - Tell the consumer that this
    102   // variable has been instantiated.
    103   virtual void HandleCXXStaticMemberVarInstantiation(VarDecl *D) {}
    104 
    105   /// \brief Callback involved at the end of a translation unit to
    106   /// notify the consumer that a vtable for the given C++ class is
    107   /// required.
    108   ///
    109   /// \param RD The class whose vtable was used.
    110   ///
    111   /// \param DefinitionRequired Whether a definition of this vtable is
    112   /// required in this translation unit; otherwise, it is only needed if
    113   /// it was actually used.
    114   virtual void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) {}
    115 
    116   /// \brief If the consumer is interested in preprocessor entities getting
    117   /// modified after their initial creation, it should return a pointer to
    118   /// a PPMutationListener here.
    119   virtual PPMutationListener *GetPPMutationListener() { return 0; }
    120 
    121   /// \brief If the consumer is interested in entities getting modified after
    122   /// their initial creation, it should return a pointer to
    123   /// an ASTMutationListener here.
    124   virtual ASTMutationListener *GetASTMutationListener() { return 0; }
    125 
    126   /// \brief If the consumer is interested in entities being deserialized from
    127   /// AST files, it should return a pointer to a ASTDeserializationListener here
    128   virtual ASTDeserializationListener *GetASTDeserializationListener() {
    129     return 0;
    130   }
    131 
    132   /// PrintStats - If desired, print any statistics.
    133   virtual void PrintStats() {}
    134 
    135   /// \brief This callback is called for each function if the Parser was
    136   /// initialized with \c SkipFunctionBodies set to \c true.
    137   ///
    138   /// \return \c true if the function's body should be skipped. The function
    139   /// body may be parsed anyway if it is needed (for instance, if it contains
    140   /// the code completion point or is constexpr).
    141   virtual bool shouldSkipFunctionBody(Decl *D) { return true; }
    142 };
    143 
    144 } // end namespace clang.
    145 
    146 #endif
    147