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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.
isMinimalImport()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.
getToContext()256     ASTContext &getToContext() const { return ToContext; }
257 
258     /// \brief Retrieve the context that AST nodes are being imported from.
getFromContext()259     ASTContext &getFromContext() const { return FromContext; }
260 
261     /// \brief Retrieve the file manager that AST nodes are being imported into.
getToFileManager()262     FileManager &getToFileManager() const { return ToFileManager; }
263 
264     /// \brief Retrieve the file manager that AST nodes are being imported from.
getFromFileManager()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.
getNonEquivalentDecls()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.
GetOriginalDecl(Decl * To)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