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