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      1 //===--- ASTImporter.h - Importing ASTs from other Contexts -----*- 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 ASTImporter class which imports AST nodes from one
     11 //  context into another context.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 #ifndef LLVM_CLANG_AST_ASTIMPORTER_H
     15 #define LLVM_CLANG_AST_ASTIMPORTER_H
     16 
     17 #include "clang/AST/DeclarationName.h"
     18 #include "clang/AST/Type.h"
     19 #include "clang/Basic/SourceLocation.h"
     20 #include "llvm/ADT/DenseMap.h"
     21 #include "llvm/ADT/DenseSet.h"
     22 #include "llvm/ADT/SmallVector.h"
     23 
     24 namespace clang {
     25   class ASTContext;
     26   class CXXCtorInitializer;
     27   class Decl;
     28   class DeclContext;
     29   class DiagnosticsEngine;
     30   class Expr;
     31   class FileManager;
     32   class IdentifierInfo;
     33   class NestedNameSpecifier;
     34   class Stmt;
     35   class TypeSourceInfo;
     36 
     37   /// \brief Imports selected nodes from one AST context into another context,
     38   /// merging AST nodes where appropriate.
     39   class ASTImporter {
     40   public:
     41     typedef llvm::DenseSet<std::pair<Decl *, Decl *> > NonEquivalentDeclSet;
     42 
     43   private:
     44     /// \brief The contexts we're importing to and from.
     45     ASTContext &ToContext, &FromContext;
     46 
     47     /// \brief The file managers we're importing to and from.
     48     FileManager &ToFileManager, &FromFileManager;
     49 
     50     /// \brief Whether to perform a minimal import.
     51     bool Minimal;
     52 
     53     /// \brief Whether the last diagnostic came from the "from" context.
     54     bool LastDiagFromFrom;
     55 
     56     /// \brief Mapping from the already-imported types in the "from" context
     57     /// to the corresponding types in the "to" context.
     58     llvm::DenseMap<const Type *, const Type *> ImportedTypes;
     59 
     60     /// \brief Mapping from the already-imported declarations in the "from"
     61     /// context to the corresponding declarations in the "to" context.
     62     llvm::DenseMap<Decl *, Decl *> ImportedDecls;
     63 
     64     /// \brief Mapping from the already-imported statements in the "from"
     65     /// context to the corresponding statements in the "to" context.
     66     llvm::DenseMap<Stmt *, Stmt *> ImportedStmts;
     67 
     68     /// \brief Mapping from the already-imported FileIDs in the "from" source
     69     /// manager to the corresponding FileIDs in the "to" source manager.
     70     llvm::DenseMap<FileID, FileID> ImportedFileIDs;
     71 
     72     /// \brief Imported, anonymous tag declarations that are missing their
     73     /// corresponding typedefs.
     74     SmallVector<TagDecl *, 4> AnonTagsWithPendingTypedefs;
     75 
     76     /// \brief Declaration (from, to) pairs that are known not to be equivalent
     77     /// (which we have already complained about).
     78     NonEquivalentDeclSet NonEquivalentDecls;
     79 
     80   public:
     81     /// \brief Create a new AST importer.
     82     ///
     83     /// \param ToContext The context we'll be importing into.
     84     ///
     85     /// \param ToFileManager The file manager we'll be importing into.
     86     ///
     87     /// \param FromContext The context we'll be importing from.
     88     ///
     89     /// \param FromFileManager The file manager we'll be importing into.
     90     ///
     91     /// \param MinimalImport If true, the importer will attempt to import
     92     /// as little as it can, e.g., by importing declarations as forward
     93     /// declarations that can be completed at a later point.
     94     ASTImporter(ASTContext &ToContext, FileManager &ToFileManager,
     95                 ASTContext &FromContext, FileManager &FromFileManager,
     96                 bool MinimalImport);
     97 
     98     virtual ~ASTImporter();
     99 
    100     /// \brief Whether the importer will perform a minimal import, creating
    101     /// to-be-completed forward declarations when possible.
    102     bool isMinimalImport() const { return Minimal; }
    103 
    104     /// \brief Import the given type from the "from" context into the "to"
    105     /// context.
    106     ///
    107     /// \returns the equivalent type in the "to" context, or a NULL type if
    108     /// an error occurred.
    109     QualType Import(QualType FromT);
    110 
    111     /// \brief Import the given type source information from the
    112     /// "from" context into the "to" context.
    113     ///
    114     /// \returns the equivalent type source information in the "to"
    115     /// context, or NULL if an error occurred.
    116     TypeSourceInfo *Import(TypeSourceInfo *FromTSI);
    117 
    118     /// \brief Import the given declaration from the "from" context into the
    119     /// "to" context.
    120     ///
    121     /// \returns the equivalent declaration in the "to" context, or a NULL type
    122     /// if an error occurred.
    123     Decl *Import(Decl *FromD);
    124 
    125     /// \brief Return the copy of the given declaration in the "to" context if
    126     /// it has already been imported from the "from" context.  Otherwise return
    127     /// NULL.
    128     Decl *GetAlreadyImportedOrNull(Decl *FromD);
    129 
    130     /// \brief Import the given declaration context from the "from"
    131     /// AST context into the "to" AST context.
    132     ///
    133     /// \returns the equivalent declaration context in the "to"
    134     /// context, or a NULL type if an error occurred.
    135     DeclContext *ImportContext(DeclContext *FromDC);
    136 
    137     /// \brief Import the given expression from the "from" context into the
    138     /// "to" context.
    139     ///
    140     /// \returns the equivalent expression in the "to" context, or NULL if
    141     /// an error occurred.
    142     Expr *Import(Expr *FromE);
    143 
    144     /// \brief Import the given statement from the "from" context into the
    145     /// "to" context.
    146     ///
    147     /// \returns the equivalent statement in the "to" context, or NULL if
    148     /// an error occurred.
    149     Stmt *Import(Stmt *FromS);
    150 
    151     /// \brief Import the given nested-name-specifier from the "from"
    152     /// context into the "to" context.
    153     ///
    154     /// \returns the equivalent nested-name-specifier in the "to"
    155     /// context, or NULL if an error occurred.
    156     NestedNameSpecifier *Import(NestedNameSpecifier *FromNNS);
    157 
    158     /// \brief Import the given nested-name-specifier from the "from"
    159     /// context into the "to" context.
    160     ///
    161     /// \returns the equivalent nested-name-specifier in the "to"
    162     /// context.
    163     NestedNameSpecifierLoc Import(NestedNameSpecifierLoc FromNNS);
    164 
    165     /// \brief Import the goven template name from the "from" context into the
    166     /// "to" context.
    167     TemplateName Import(TemplateName From);
    168 
    169     /// \brief Import the given source location from the "from" context into
    170     /// the "to" context.
    171     ///
    172     /// \returns the equivalent source location in the "to" context, or an
    173     /// invalid source location if an error occurred.
    174     SourceLocation Import(SourceLocation FromLoc);
    175 
    176     /// \brief Import the given source range from the "from" context into
    177     /// the "to" context.
    178     ///
    179     /// \returns the equivalent source range in the "to" context, or an
    180     /// invalid source location if an error occurred.
    181     SourceRange Import(SourceRange FromRange);
    182 
    183     /// \brief Import the given declaration name from the "from"
    184     /// context into the "to" context.
    185     ///
    186     /// \returns the equivalent declaration name in the "to" context,
    187     /// or an empty declaration name if an error occurred.
    188     DeclarationName Import(DeclarationName FromName);
    189 
    190     /// \brief Import the given identifier from the "from" context
    191     /// into the "to" context.
    192     ///
    193     /// \returns the equivalent identifier in the "to" context.
    194     IdentifierInfo *Import(const IdentifierInfo *FromId);
    195 
    196     /// \brief Import the given Objective-C selector from the "from"
    197     /// context into the "to" context.
    198     ///
    199     /// \returns the equivalent selector in the "to" context.
    200     Selector Import(Selector FromSel);
    201 
    202     /// \brief Import the given file ID from the "from" context into the
    203     /// "to" context.
    204     ///
    205     /// \returns the equivalent file ID in the source manager of the "to"
    206     /// context.
    207     FileID Import(FileID);
    208 
    209     /// \brief Import the given C++ constructor initializer from the "from"
    210     /// context into the "to" context.
    211     ///
    212     /// \returns the equivalent initializer in the "to" context.
    213     CXXCtorInitializer *Import(CXXCtorInitializer *FromInit);
    214 
    215 
    216 
    217     /// \brief Import the definition of the given declaration, including all of
    218     /// the declarations it contains.
    219     ///
    220     /// This routine is intended to be used
    221     void ImportDefinition(Decl *From);
    222 
    223     /// \brief Cope with a name conflict when importing a declaration into the
    224     /// given context.
    225     ///
    226     /// This routine is invoked whenever there is a name conflict while
    227     /// importing a declaration. The returned name will become the name of the
    228     /// imported declaration. By default, the returned name is the same as the
    229     /// original name, leaving the conflict unresolve such that name lookup
    230     /// for this name is likely to find an ambiguity later.
    231     ///
    232     /// Subclasses may override this routine to resolve the conflict, e.g., by
    233     /// renaming the declaration being imported.
    234     ///
    235     /// \param Name the name of the declaration being imported, which conflicts
    236     /// with other declarations.
    237     ///
    238     /// \param DC the declaration context (in the "to" AST context) in which
    239     /// the name is being imported.
    240     ///
    241     /// \param IDNS the identifier namespace in which the name will be found.
    242     ///
    243     /// \param Decls the set of declarations with the same name as the
    244     /// declaration being imported.
    245     ///
    246     /// \param NumDecls the number of conflicting declarations in \p Decls.
    247     ///
    248     /// \returns the name that the newly-imported declaration should have.
    249     virtual DeclarationName HandleNameConflict(DeclarationName Name,
    250                                                DeclContext *DC,
    251                                                unsigned IDNS,
    252                                                NamedDecl **Decls,
    253                                                unsigned NumDecls);
    254 
    255     /// \brief Retrieve the context that AST nodes are being imported into.
    256     ASTContext &getToContext() const { return ToContext; }
    257 
    258     /// \brief Retrieve the context that AST nodes are being imported from.
    259     ASTContext &getFromContext() const { return FromContext; }
    260 
    261     /// \brief Retrieve the file manager that AST nodes are being imported into.
    262     FileManager &getToFileManager() const { return ToFileManager; }
    263 
    264     /// \brief Retrieve the file manager that AST nodes are being imported from.
    265     FileManager &getFromFileManager() const { return FromFileManager; }
    266 
    267     /// \brief Report a diagnostic in the "to" context.
    268     DiagnosticBuilder ToDiag(SourceLocation Loc, unsigned DiagID);
    269 
    270     /// \brief Report a diagnostic in the "from" context.
    271     DiagnosticBuilder FromDiag(SourceLocation Loc, unsigned DiagID);
    272 
    273     /// \brief Return the set of declarations that we know are not equivalent.
    274     NonEquivalentDeclSet &getNonEquivalentDecls() { return NonEquivalentDecls; }
    275 
    276     /// \brief Called for ObjCInterfaceDecl, ObjCProtocolDecl, and TagDecl.
    277     /// Mark the Decl as complete, filling it in as much as possible.
    278     ///
    279     /// \param D A declaration in the "to" context.
    280     virtual void CompleteDecl(Decl* D);
    281 
    282     /// \brief Note that we have imported the "from" declaration by mapping it
    283     /// to the (potentially-newly-created) "to" declaration.
    284     ///
    285     /// Subclasses can override this function to observe all of the \c From ->
    286     /// \c To declaration mappings as they are imported.
    287     virtual Decl *Imported(Decl *From, Decl *To);
    288 
    289     /// \brief Called by StructuralEquivalenceContext.  If a RecordDecl is
    290     /// being compared to another RecordDecl as part of import, completing the
    291     /// other RecordDecl may trigger importation of the first RecordDecl. This
    292     /// happens especially for anonymous structs.  If the original of the second
    293     /// RecordDecl can be found, we can complete it without the need for
    294     /// importation, eliminating this loop.
    295     virtual Decl *GetOriginalDecl(Decl *To) { return nullptr; }
    296 
    297     /// \brief Determine whether the given types are structurally
    298     /// equivalent.
    299     bool IsStructurallyEquivalent(QualType From, QualType To,
    300                                   bool Complain = true);
    301   };
    302 }
    303 
    304 #endif // LLVM_CLANG_AST_ASTIMPORTER_H
    305