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Diffstat (limited to 'clang-r353983/include/clang/AST/CXXInheritance.h')
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diff --git a/clang-r353983/include/clang/AST/CXXInheritance.h b/clang-r353983/include/clang/AST/CXXInheritance.h new file mode 100644 index 00000000..bb2ad9c6 --- /dev/null +++ b/clang-r353983/include/clang/AST/CXXInheritance.h @@ -0,0 +1,377 @@ +//===- CXXInheritance.h - C++ Inheritance -----------------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file provides routines that help analyzing C++ inheritance hierarchies. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_AST_CXXINHERITANCE_H +#define LLVM_CLANG_AST_CXXINHERITANCE_H + +#include "clang/AST/DeclBase.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclarationName.h" +#include "clang/AST/Type.h" +#include "clang/AST/TypeOrdering.h" +#include "clang/Basic/Specifiers.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/MapVector.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/iterator_range.h" +#include <list> +#include <memory> +#include <utility> + +namespace clang { + +class ASTContext; +class NamedDecl; + +/// Represents an element in a path from a derived class to a +/// base class. +/// +/// Each step in the path references the link from a +/// derived class to one of its direct base classes, along with a +/// base "number" that identifies which base subobject of the +/// original derived class we are referencing. +struct CXXBasePathElement { + /// The base specifier that states the link from a derived + /// class to a base class, which will be followed by this base + /// path element. + const CXXBaseSpecifier *Base; + + /// The record decl of the class that the base is a base of. + const CXXRecordDecl *Class; + + /// Identifies which base class subobject (of type + /// \c Base->getType()) this base path element refers to. + /// + /// This value is only valid if \c !Base->isVirtual(), because there + /// is no base numbering for the zero or one virtual bases of a + /// given type. + int SubobjectNumber; +}; + +/// Represents a path from a specific derived class +/// (which is not represented as part of the path) to a particular +/// (direct or indirect) base class subobject. +/// +/// Individual elements in the path are described by the \c CXXBasePathElement +/// structure, which captures both the link from a derived class to one of its +/// direct bases and identification describing which base class +/// subobject is being used. +class CXXBasePath : public SmallVector<CXXBasePathElement, 4> { +public: + /// The access along this inheritance path. This is only + /// calculated when recording paths. AS_none is a special value + /// used to indicate a path which permits no legal access. + AccessSpecifier Access = AS_public; + + CXXBasePath() = default; + + /// The set of declarations found inside this base class + /// subobject. + DeclContext::lookup_result Decls; + + void clear() { + SmallVectorImpl<CXXBasePathElement>::clear(); + Access = AS_public; + } +}; + +/// BasePaths - Represents the set of paths from a derived class to +/// one of its (direct or indirect) bases. For example, given the +/// following class hierarchy: +/// +/// @code +/// class A { }; +/// class B : public A { }; +/// class C : public A { }; +/// class D : public B, public C{ }; +/// @endcode +/// +/// There are two potential BasePaths to represent paths from D to a +/// base subobject of type A. One path is (D,0) -> (B,0) -> (A,0) +/// and another is (D,0)->(C,0)->(A,1). These two paths actually +/// refer to two different base class subobjects of the same type, +/// so the BasePaths object refers to an ambiguous path. On the +/// other hand, consider the following class hierarchy: +/// +/// @code +/// class A { }; +/// class B : public virtual A { }; +/// class C : public virtual A { }; +/// class D : public B, public C{ }; +/// @endcode +/// +/// Here, there are two potential BasePaths again, (D, 0) -> (B, 0) +/// -> (A,v) and (D, 0) -> (C, 0) -> (A, v), but since both of them +/// refer to the same base class subobject of type A (the virtual +/// one), there is no ambiguity. +class CXXBasePaths { + friend class CXXRecordDecl; + + /// The type from which this search originated. + CXXRecordDecl *Origin = nullptr; + + /// Paths - The actual set of paths that can be taken from the + /// derived class to the same base class. + std::list<CXXBasePath> Paths; + + /// ClassSubobjects - Records the class subobjects for each class + /// type that we've seen. The first element IsVirtBase says + /// whether we found a path to a virtual base for that class type, + /// while NumberOfNonVirtBases contains the number of non-virtual base + /// class subobjects for that class type. The key of the map is + /// the cv-unqualified canonical type of the base class subobject. + struct IsVirtBaseAndNumberNonVirtBases { + unsigned IsVirtBase : 1; + unsigned NumberOfNonVirtBases : 31; + }; + llvm::SmallDenseMap<QualType, IsVirtBaseAndNumberNonVirtBases, 8> + ClassSubobjects; + + /// VisitedDependentRecords - Records the dependent records that have been + /// already visited. + llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedDependentRecords; + + /// DetectedVirtual - The base class that is virtual. + const RecordType *DetectedVirtual = nullptr; + + /// ScratchPath - A BasePath that is used by Sema::lookupInBases + /// to help build the set of paths. + CXXBasePath ScratchPath; + + /// Array of the declarations that have been found. This + /// array is constructed only if needed, e.g., to iterate over the + /// results within LookupResult. + std::unique_ptr<NamedDecl *[]> DeclsFound; + unsigned NumDeclsFound = 0; + + /// FindAmbiguities - Whether Sema::IsDerivedFrom should try find + /// ambiguous paths while it is looking for a path from a derived + /// type to a base type. + bool FindAmbiguities; + + /// RecordPaths - Whether Sema::IsDerivedFrom should record paths + /// while it is determining whether there are paths from a derived + /// type to a base type. + bool RecordPaths; + + /// DetectVirtual - Whether Sema::IsDerivedFrom should abort the search + /// if it finds a path that goes across a virtual base. The virtual class + /// is also recorded. + bool DetectVirtual; + + void ComputeDeclsFound(); + + bool lookupInBases(ASTContext &Context, const CXXRecordDecl *Record, + CXXRecordDecl::BaseMatchesCallback BaseMatches, + bool LookupInDependent = false); + +public: + using paths_iterator = std::list<CXXBasePath>::iterator; + using const_paths_iterator = std::list<CXXBasePath>::const_iterator; + using decl_iterator = NamedDecl **; + + /// BasePaths - Construct a new BasePaths structure to record the + /// paths for a derived-to-base search. + explicit CXXBasePaths(bool FindAmbiguities = true, bool RecordPaths = true, + bool DetectVirtual = true) + : FindAmbiguities(FindAmbiguities), RecordPaths(RecordPaths), + DetectVirtual(DetectVirtual) {} + + paths_iterator begin() { return Paths.begin(); } + paths_iterator end() { return Paths.end(); } + const_paths_iterator begin() const { return Paths.begin(); } + const_paths_iterator end() const { return Paths.end(); } + + CXXBasePath& front() { return Paths.front(); } + const CXXBasePath& front() const { return Paths.front(); } + + using decl_range = llvm::iterator_range<decl_iterator>; + + decl_range found_decls(); + + /// Determine whether the path from the most-derived type to the + /// given base type is ambiguous (i.e., it refers to multiple subobjects of + /// the same base type). + bool isAmbiguous(CanQualType BaseType); + + /// Whether we are finding multiple paths to detect ambiguities. + bool isFindingAmbiguities() const { return FindAmbiguities; } + + /// Whether we are recording paths. + bool isRecordingPaths() const { return RecordPaths; } + + /// Specify whether we should be recording paths or not. + void setRecordingPaths(bool RP) { RecordPaths = RP; } + + /// Whether we are detecting virtual bases. + bool isDetectingVirtual() const { return DetectVirtual; } + + /// The virtual base discovered on the path (if we are merely + /// detecting virtuals). + const RecordType* getDetectedVirtual() const { + return DetectedVirtual; + } + + /// Retrieve the type from which this base-paths search + /// began + CXXRecordDecl *getOrigin() const { return Origin; } + void setOrigin(CXXRecordDecl *Rec) { Origin = Rec; } + + /// Clear the base-paths results. + void clear(); + + /// Swap this data structure's contents with another CXXBasePaths + /// object. + void swap(CXXBasePaths &Other); +}; + +/// Uniquely identifies a virtual method within a class +/// hierarchy by the method itself and a class subobject number. +struct UniqueVirtualMethod { + /// The overriding virtual method. + CXXMethodDecl *Method = nullptr; + + /// The subobject in which the overriding virtual method + /// resides. + unsigned Subobject = 0; + + /// The virtual base class subobject of which this overridden + /// virtual method is a part. Note that this records the closest + /// derived virtual base class subobject. + const CXXRecordDecl *InVirtualSubobject = nullptr; + + UniqueVirtualMethod() = default; + + UniqueVirtualMethod(CXXMethodDecl *Method, unsigned Subobject, + const CXXRecordDecl *InVirtualSubobject) + : Method(Method), Subobject(Subobject), + InVirtualSubobject(InVirtualSubobject) {} + + friend bool operator==(const UniqueVirtualMethod &X, + const UniqueVirtualMethod &Y) { + return X.Method == Y.Method && X.Subobject == Y.Subobject && + X.InVirtualSubobject == Y.InVirtualSubobject; + } + + friend bool operator!=(const UniqueVirtualMethod &X, + const UniqueVirtualMethod &Y) { + return !(X == Y); + } +}; + +/// The set of methods that override a given virtual method in +/// each subobject where it occurs. +/// +/// The first part of the pair is the subobject in which the +/// overridden virtual function occurs, while the second part of the +/// pair is the virtual method that overrides it (including the +/// subobject in which that virtual function occurs). +class OverridingMethods { + using ValuesT = SmallVector<UniqueVirtualMethod, 4>; + using MapType = llvm::MapVector<unsigned, ValuesT>; + + MapType Overrides; + +public: + // Iterate over the set of subobjects that have overriding methods. + using iterator = MapType::iterator; + using const_iterator = MapType::const_iterator; + + iterator begin() { return Overrides.begin(); } + const_iterator begin() const { return Overrides.begin(); } + iterator end() { return Overrides.end(); } + const_iterator end() const { return Overrides.end(); } + unsigned size() const { return Overrides.size(); } + + // Iterate over the set of overriding virtual methods in a given + // subobject. + using overriding_iterator = + SmallVectorImpl<UniqueVirtualMethod>::iterator; + using overriding_const_iterator = + SmallVectorImpl<UniqueVirtualMethod>::const_iterator; + + // Add a new overriding method for a particular subobject. + void add(unsigned OverriddenSubobject, UniqueVirtualMethod Overriding); + + // Add all of the overriding methods from "other" into overrides for + // this method. Used when merging the overrides from multiple base + // class subobjects. + void add(const OverridingMethods &Other); + + // Replace all overriding virtual methods in all subobjects with the + // given virtual method. + void replaceAll(UniqueVirtualMethod Overriding); +}; + +/// A mapping from each virtual member function to its set of +/// final overriders. +/// +/// Within a class hierarchy for a given derived class, each virtual +/// member function in that hierarchy has one or more "final +/// overriders" (C++ [class.virtual]p2). A final overrider for a +/// virtual function "f" is the virtual function that will actually be +/// invoked when dispatching a call to "f" through the +/// vtable. Well-formed classes have a single final overrider for each +/// virtual function; in abstract classes, the final overrider for at +/// least one virtual function is a pure virtual function. Due to +/// multiple, virtual inheritance, it is possible for a class to have +/// more than one final overrider. Athough this is an error (per C++ +/// [class.virtual]p2), it is not considered an error here: the final +/// overrider map can represent multiple final overriders for a +/// method, and it is up to the client to determine whether they are +/// problem. For example, the following class \c D has two final +/// overriders for the virtual function \c A::f(), one in \c C and one +/// in \c D: +/// +/// \code +/// struct A { virtual void f(); }; +/// struct B : virtual A { virtual void f(); }; +/// struct C : virtual A { virtual void f(); }; +/// struct D : B, C { }; +/// \endcode +/// +/// This data structure contains a mapping from every virtual +/// function *that does not override an existing virtual function* and +/// in every subobject where that virtual function occurs to the set +/// of virtual functions that override it. Thus, the same virtual +/// function \c A::f can actually occur in multiple subobjects of type +/// \c A due to multiple inheritance, and may be overridden by +/// different virtual functions in each, as in the following example: +/// +/// \code +/// struct A { virtual void f(); }; +/// struct B : A { virtual void f(); }; +/// struct C : A { virtual void f(); }; +/// struct D : B, C { }; +/// \endcode +/// +/// Unlike in the previous example, where the virtual functions \c +/// B::f and \c C::f both overrode \c A::f in the same subobject of +/// type \c A, in this example the two virtual functions both override +/// \c A::f but in *different* subobjects of type A. This is +/// represented by numbering the subobjects in which the overridden +/// and the overriding virtual member functions are located. Subobject +/// 0 represents the virtual base class subobject of that type, while +/// subobject numbers greater than 0 refer to non-virtual base class +/// subobjects of that type. +class CXXFinalOverriderMap + : public llvm::MapVector<const CXXMethodDecl *, OverridingMethods> {}; + +/// A set of all the primary bases for a class. +class CXXIndirectPrimaryBaseSet + : public llvm::SmallSet<const CXXRecordDecl*, 32> {}; + +} // namespace clang + +#endif // LLVM_CLANG_AST_CXXINHERITANCE_H |