1 //===------ CXXInheritance.h - C++ Inheritance ------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file provides routines that help analyzing C++ inheritance hierarchies.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_AST_CXXINHERITANCE_H
15 #define LLVM_CLANG_AST_CXXINHERITANCE_H
17 #include "clang/AST/DeclarationName.h"
18 #include "clang/AST/DeclBase.h"
19 #include "clang/AST/Type.h"
20 #include "clang/AST/TypeOrdering.h"
21 #include "llvm/ADT/SmallVector.h"
28 class CXXBaseSpecifier;
33 /// \brief Represents an element in a path from a derived class to a
36 /// Each step in the path references the link from a
37 /// derived class to one of its direct base classes, along with a
38 /// base "number" that identifies which base subobject of the
39 /// original derived class we are referencing.
40 struct CXXBasePathElement {
41 /// \brief The base specifier that states the link from a derived
42 /// class to a base class, which will be followed by this base
44 const CXXBaseSpecifier *Base;
46 /// \brief The record decl of the class that the base is a base of.
47 const CXXRecordDecl *Class;
49 /// \brief Identifies which base class subobject (of type
50 /// \c Base->getType()) this base path element refers to.
52 /// This value is only valid if \c !Base->isVirtual(), because there
53 /// is no base numbering for the zero or one virtual bases of a
58 /// \brief Represents a path from a specific derived class
59 /// (which is not represented as part of the path) to a particular
60 /// (direct or indirect) base class subobject.
62 /// Individual elements in the path are described by the \c CXXBasePathElement
63 /// structure, which captures both the link from a derived class to one of its
64 /// direct bases and identification describing which base class
65 /// subobject is being used.
66 class CXXBasePath : public llvm::SmallVector<CXXBasePathElement, 4> {
68 CXXBasePath() : Access(AS_public) {}
70 /// \brief The access along this inheritance path. This is only
71 /// calculated when recording paths. AS_none is a special value
72 /// used to indicate a path which permits no legal access.
73 AccessSpecifier Access;
75 /// \brief The set of declarations found inside this base class
77 DeclContext::lookup_result Decls;
80 llvm::SmallVectorImpl<CXXBasePathElement>::clear();
85 /// BasePaths - Represents the set of paths from a derived class to
86 /// one of its (direct or indirect) bases. For example, given the
87 /// following class hierachy:
91 /// class B : public A { };
92 /// class C : public A { };
93 /// class D : public B, public C{ };
96 /// There are two potential BasePaths to represent paths from D to a
97 /// base subobject of type A. One path is (D,0) -> (B,0) -> (A,0)
98 /// and another is (D,0)->(C,0)->(A,1). These two paths actually
99 /// refer to two different base class subobjects of the same type,
100 /// so the BasePaths object refers to an ambiguous path. On the
101 /// other hand, consider the following class hierarchy:
105 /// class B : public virtual A { };
106 /// class C : public virtual A { };
107 /// class D : public B, public C{ };
110 /// Here, there are two potential BasePaths again, (D, 0) -> (B, 0)
111 /// -> (A,v) and (D, 0) -> (C, 0) -> (A, v), but since both of them
112 /// refer to the same base class subobject of type A (the virtual
113 /// one), there is no ambiguity.
115 /// \brief The type from which this search originated.
116 CXXRecordDecl *Origin;
118 /// Paths - The actual set of paths that can be taken from the
119 /// derived class to the same base class.
120 std::list<CXXBasePath> Paths;
122 /// ClassSubobjects - Records the class subobjects for each class
123 /// type that we've seen. The first element in the pair says
124 /// whether we found a path to a virtual base for that class type,
125 /// while the element contains the number of non-virtual base
126 /// class subobjects for that class type. The key of the map is
127 /// the cv-unqualified canonical type of the base class subobject.
128 std::map<QualType, std::pair<bool, unsigned>, QualTypeOrdering>
131 /// FindAmbiguities - Whether Sema::IsDerivedFrom should try find
132 /// ambiguous paths while it is looking for a path from a derived
133 /// type to a base type.
134 bool FindAmbiguities;
136 /// RecordPaths - Whether Sema::IsDerivedFrom should record paths
137 /// while it is determining whether there are paths from a derived
138 /// type to a base type.
141 /// DetectVirtual - Whether Sema::IsDerivedFrom should abort the search
142 /// if it finds a path that goes across a virtual base. The virtual class
143 /// is also recorded.
146 /// ScratchPath - A BasePath that is used by Sema::lookupInBases
147 /// to help build the set of paths.
148 CXXBasePath ScratchPath;
150 /// DetectedVirtual - The base class that is virtual.
151 const RecordType *DetectedVirtual;
153 /// \brief Array of the declarations that have been found. This
154 /// array is constructed only if needed, e.g., to iterate over the
155 /// results within LookupResult.
156 NamedDecl **DeclsFound;
157 unsigned NumDeclsFound;
159 friend class CXXRecordDecl;
161 void ComputeDeclsFound();
164 typedef std::list<CXXBasePath>::iterator paths_iterator;
165 typedef std::list<CXXBasePath>::const_iterator const_paths_iterator;
166 typedef NamedDecl **decl_iterator;
168 /// BasePaths - Construct a new BasePaths structure to record the
169 /// paths for a derived-to-base search.
170 explicit CXXBasePaths(bool FindAmbiguities = true,
171 bool RecordPaths = true,
172 bool DetectVirtual = true)
173 : FindAmbiguities(FindAmbiguities), RecordPaths(RecordPaths),
174 DetectVirtual(DetectVirtual), DetectedVirtual(0), DeclsFound(0),
177 ~CXXBasePaths() { delete [] DeclsFound; }
179 paths_iterator begin() { return Paths.begin(); }
180 paths_iterator end() { return Paths.end(); }
181 const_paths_iterator begin() const { return Paths.begin(); }
182 const_paths_iterator end() const { return Paths.end(); }
184 CXXBasePath& front() { return Paths.front(); }
185 const CXXBasePath& front() const { return Paths.front(); }
187 decl_iterator found_decls_begin();
188 decl_iterator found_decls_end();
190 /// \brief Determine whether the path from the most-derived type to the
191 /// given base type is ambiguous (i.e., it refers to multiple subobjects of
192 /// the same base type).
193 bool isAmbiguous(QualType BaseType);
195 /// \brief Whether we are finding multiple paths to detect ambiguities.
196 bool isFindingAmbiguities() const { return FindAmbiguities; }
198 /// \brief Whether we are recording paths.
199 bool isRecordingPaths() const { return RecordPaths; }
201 /// \brief Specify whether we should be recording paths or not.
202 void setRecordingPaths(bool RP) { RecordPaths = RP; }
204 /// \brief Whether we are detecting virtual bases.
205 bool isDetectingVirtual() const { return DetectVirtual; }
207 /// \brief The virtual base discovered on the path (if we are merely
208 /// detecting virtuals).
209 const RecordType* getDetectedVirtual() const {
210 return DetectedVirtual;
213 /// \brief Retrieve the type from which this base-paths search
215 CXXRecordDecl *getOrigin() const { return Origin; }
216 void setOrigin(CXXRecordDecl *Rec) { Origin = Rec; }
218 /// \brief Clear the base-paths results.
221 /// \brief Swap this data structure's contents with another CXXBasePaths
223 void swap(CXXBasePaths &Other);
226 } // end namespace clang