Coverage Report

Created: 2021-01-23 06:44

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/AST/CXXInheritance.h
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//===- CXXInheritance.h - C++ Inheritance -----------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides routines that help analyzing C++ inheritance hierarchies.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_AST_CXXINHERITANCE_H
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#define LLVM_CLANG_AST_CXXINHERITANCE_H
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#include "clang/AST/DeclBase.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/DeclarationName.h"
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#include "clang/AST/Type.h"
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#include "clang/AST/TypeOrdering.h"
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#include "clang/Basic/Specifiers.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/MapVector.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/iterator_range.h"
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#include <list>
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#include <memory>
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#include <utility>
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namespace clang {
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class ASTContext;
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class NamedDecl;
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/// Represents an element in a path from a derived class to a
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/// base class.
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///
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/// Each step in the path references the link from a
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/// derived class to one of its direct base classes, along with a
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/// base "number" that identifies which base subobject of the
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/// original derived class we are referencing.
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struct CXXBasePathElement {
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  /// The base specifier that states the link from a derived
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  /// class to a base class, which will be followed by this base
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  /// path element.
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  const CXXBaseSpecifier *Base;
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  /// The record decl of the class that the base is a base of.
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  const CXXRecordDecl *Class;
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  /// Identifies which base class subobject (of type
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  /// \c Base->getType()) this base path element refers to.
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  ///
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  /// This value is only valid if \c !Base->isVirtual(), because there
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  /// is no base numbering for the zero or one virtual bases of a
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  /// given type.
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  int SubobjectNumber;
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};
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/// Represents a path from a specific derived class
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/// (which is not represented as part of the path) to a particular
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/// (direct or indirect) base class subobject.
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///
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/// Individual elements in the path are described by the \c CXXBasePathElement
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/// structure, which captures both the link from a derived class to one of its
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/// direct bases and identification describing which base class
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/// subobject is being used.
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class CXXBasePath : public SmallVector<CXXBasePathElement, 4> {
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public:
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  /// The access along this inheritance path.  This is only
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  /// calculated when recording paths.  AS_none is a special value
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  /// used to indicate a path which permits no legal access.
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  AccessSpecifier Access = AS_public;
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6.82M
  CXXBasePath() = default;
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  /// The set of declarations found inside this base class
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  /// subobject.
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  DeclContext::lookup_result Decls;
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  void clear() {
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    SmallVectorImpl<CXXBasePathElement>::clear();
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    Access = AS_public;
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  }
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};
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/// BasePaths - Represents the set of paths from a derived class to
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/// one of its (direct or indirect) bases. For example, given the
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/// following class hierarchy:
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///
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/// @code
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/// class A { };
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/// class B : public A { };
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/// class C : public A { };
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/// class D : public B, public C{ };
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/// @endcode
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///
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/// There are two potential BasePaths to represent paths from D to a
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/// base subobject of type A. One path is (D,0) -> (B,0) -> (A,0)
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/// and another is (D,0)->(C,0)->(A,1). These two paths actually
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/// refer to two different base class subobjects of the same type,
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/// so the BasePaths object refers to an ambiguous path. On the
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/// other hand, consider the following class hierarchy:
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///
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/// @code
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/// class A { };
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/// class B : public virtual A { };
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/// class C : public virtual A { };
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/// class D : public B, public C{ };
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/// @endcode
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///
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/// Here, there are two potential BasePaths again, (D, 0) -> (B, 0)
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/// -> (A,v) and (D, 0) -> (C, 0) -> (A, v), but since both of them
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/// refer to the same base class subobject of type A (the virtual
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/// one), there is no ambiguity.
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class CXXBasePaths {
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  friend class CXXRecordDecl;
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  /// The type from which this search originated.
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  const CXXRecordDecl *Origin = nullptr;
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  /// Paths - The actual set of paths that can be taken from the
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  /// derived class to the same base class.
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  std::list<CXXBasePath> Paths;
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  /// ClassSubobjects - Records the class subobjects for each class
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  /// type that we've seen. The first element IsVirtBase says
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  /// whether we found a path to a virtual base for that class type,
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  /// while NumberOfNonVirtBases contains the number of non-virtual base
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  /// class subobjects for that class type. The key of the map is
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  /// the cv-unqualified canonical type of the base class subobject.
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  struct IsVirtBaseAndNumberNonVirtBases {
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    unsigned IsVirtBase : 1;
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    unsigned NumberOfNonVirtBases : 31;
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  };
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  llvm::SmallDenseMap<QualType, IsVirtBaseAndNumberNonVirtBases, 8>
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      ClassSubobjects;
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  /// VisitedDependentRecords - Records the dependent records that have been
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  /// already visited.
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  llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedDependentRecords;
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  /// DetectedVirtual - The base class that is virtual.
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  const RecordType *DetectedVirtual = nullptr;
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  /// ScratchPath - A BasePath that is used by Sema::lookupInBases
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  /// to help build the set of paths.
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  CXXBasePath ScratchPath;
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  /// FindAmbiguities - Whether Sema::IsDerivedFrom should try find
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  /// ambiguous paths while it is looking for a path from a derived
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  /// type to a base type.
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  bool FindAmbiguities;
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  /// RecordPaths - Whether Sema::IsDerivedFrom should record paths
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  /// while it is determining whether there are paths from a derived
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  /// type to a base type.
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  bool RecordPaths;
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  /// DetectVirtual - Whether Sema::IsDerivedFrom should abort the search
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  /// if it finds a path that goes across a virtual base. The virtual class
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  /// is also recorded.
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  bool DetectVirtual;
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  bool lookupInBases(ASTContext &Context, const CXXRecordDecl *Record,
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                     CXXRecordDecl::BaseMatchesCallback BaseMatches,
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                     bool LookupInDependent = false);
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public:
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  using paths_iterator = std::list<CXXBasePath>::iterator;
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  using const_paths_iterator = std::list<CXXBasePath>::const_iterator;
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  using decl_iterator = NamedDecl **;
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  /// BasePaths - Construct a new BasePaths structure to record the
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  /// paths for a derived-to-base search.
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  explicit CXXBasePaths(bool FindAmbiguities = true, bool RecordPaths = true,
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                        bool DetectVirtual = true)
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      : FindAmbiguities(FindAmbiguities), RecordPaths(RecordPaths),
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6.82M
        DetectVirtual(DetectVirtual) {}
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  paths_iterator begin() { return Paths.begin(); }
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  paths_iterator end()   { return Paths.end(); }
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  const_paths_iterator begin() const { return Paths.begin(); }
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  const_paths_iterator end()   const { return Paths.end(); }
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  CXXBasePath&       front()       { return Paths.front(); }
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  const CXXBasePath& front() const { return Paths.front(); }
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  using decl_range = llvm::iterator_range<decl_iterator>;
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  /// Determine whether the path from the most-derived type to the
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  /// given base type is ambiguous (i.e., it refers to multiple subobjects of
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  /// the same base type).
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  bool isAmbiguous(CanQualType BaseType);
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  /// Whether we are finding multiple paths to detect ambiguities.
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809k
  bool isFindingAmbiguities() const { return FindAmbiguities; }
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  /// Whether we are recording paths.
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  bool isRecordingPaths() const { return RecordPaths; }
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  /// Specify whether we should be recording paths or not.
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  void setRecordingPaths(bool RP) { RecordPaths = RP; }
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  /// Whether we are detecting virtual bases.
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  bool isDetectingVirtual() const { return DetectVirtual; }
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  /// The virtual base discovered on the path (if we are merely
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  /// detecting virtuals).
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  const RecordType* getDetectedVirtual() const {
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    return DetectedVirtual;
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  }
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  /// Retrieve the type from which this base-paths search
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  /// began
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  const CXXRecordDecl *getOrigin() const { return Origin; }
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4.90M
  void setOrigin(const CXXRecordDecl *Rec) { Origin = Rec; }
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  /// Clear the base-paths results.
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  void clear();
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  /// Swap this data structure's contents with another CXXBasePaths
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  /// object.
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  void swap(CXXBasePaths &Other);
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};
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/// Uniquely identifies a virtual method within a class
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/// hierarchy by the method itself and a class subobject number.
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struct UniqueVirtualMethod {
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  /// The overriding virtual method.
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  CXXMethodDecl *Method = nullptr;
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  /// The subobject in which the overriding virtual method
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  /// resides.
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  unsigned Subobject = 0;
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  /// The virtual base class subobject of which this overridden
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  /// virtual method is a part. Note that this records the closest
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  /// derived virtual base class subobject.
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  const CXXRecordDecl *InVirtualSubobject = nullptr;
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  UniqueVirtualMethod() = default;
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  UniqueVirtualMethod(CXXMethodDecl *Method, unsigned Subobject,
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                      const CXXRecordDecl *InVirtualSubobject)
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      : Method(Method), Subobject(Subobject),
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        InVirtualSubobject(InVirtualSubobject) {}
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  friend bool operator==(const UniqueVirtualMethod &X,
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                         const UniqueVirtualMethod &Y) {
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    return X.Method == Y.Method && 
X.Subobject == Y.Subobject198
&&
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      X.InVirtualSubobject == Y.InVirtualSubobject;
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  }
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  friend bool operator!=(const UniqueVirtualMethod &X,
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                         const UniqueVirtualMethod &Y) {
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    return !(X == Y);
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  }
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};
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/// The set of methods that override a given virtual method in
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/// each subobject where it occurs.
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///
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/// The first part of the pair is the subobject in which the
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/// overridden virtual function occurs, while the second part of the
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/// pair is the virtual method that overrides it (including the
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/// subobject in which that virtual function occurs).
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class OverridingMethods {
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  using ValuesT = SmallVector<UniqueVirtualMethod, 4>;
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  using MapType = llvm::MapVector<unsigned, ValuesT>;
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  MapType Overrides;
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public:
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  // Iterate over the set of subobjects that have overriding methods.
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  using iterator = MapType::iterator;
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  using const_iterator = MapType::const_iterator;
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  iterator begin() { return Overrides.begin(); }
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  const_iterator begin() const { return Overrides.begin(); }
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  iterator end() { return Overrides.end(); }
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  const_iterator end() const { return Overrides.end(); }
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  unsigned size() const { return Overrides.size(); }
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  // Iterate over the set of overriding virtual methods in a given
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  // subobject.
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  using overriding_iterator =
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      SmallVectorImpl<UniqueVirtualMethod>::iterator;
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  using overriding_const_iterator =
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      SmallVectorImpl<UniqueVirtualMethod>::const_iterator;
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  // Add a new overriding method for a particular subobject.
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  void add(unsigned OverriddenSubobject, UniqueVirtualMethod Overriding);
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  // Add all of the overriding methods from "other" into overrides for
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  // this method. Used when merging the overrides from multiple base
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  // class subobjects.
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  void add(const OverridingMethods &Other);
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  // Replace all overriding virtual methods in all subobjects with the
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  // given virtual method.
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  void replaceAll(UniqueVirtualMethod Overriding);
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};
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/// A mapping from each virtual member function to its set of
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/// final overriders.
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///
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/// Within a class hierarchy for a given derived class, each virtual
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/// member function in that hierarchy has one or more "final
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/// overriders" (C++ [class.virtual]p2). A final overrider for a
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/// virtual function "f" is the virtual function that will actually be
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/// invoked when dispatching a call to "f" through the
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/// vtable. Well-formed classes have a single final overrider for each
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/// virtual function; in abstract classes, the final overrider for at
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/// least one virtual function is a pure virtual function. Due to
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/// multiple, virtual inheritance, it is possible for a class to have
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/// more than one final overrider. Athough this is an error (per C++
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/// [class.virtual]p2), it is not considered an error here: the final
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/// overrider map can represent multiple final overriders for a
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/// method, and it is up to the client to determine whether they are
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/// problem. For example, the following class \c D has two final
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/// overriders for the virtual function \c A::f(), one in \c C and one
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/// in \c D:
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///
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/// \code
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///   struct A { virtual void f(); };
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///   struct B : virtual A { virtual void f(); };
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///   struct C : virtual A { virtual void f(); };
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///   struct D : B, C { };
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/// \endcode
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///
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/// This data structure contains a mapping from every virtual
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/// function *that does not override an existing virtual function* and
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/// in every subobject where that virtual function occurs to the set
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/// of virtual functions that override it. Thus, the same virtual
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/// function \c A::f can actually occur in multiple subobjects of type
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/// \c A due to multiple inheritance, and may be overridden by
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/// different virtual functions in each, as in the following example:
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///
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/// \code
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///   struct A { virtual void f(); };
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///   struct B : A { virtual void f(); };
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///   struct C : A { virtual void f(); };
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///   struct D : B, C { };
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/// \endcode
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///
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/// Unlike in the previous example, where the virtual functions \c
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/// B::f and \c C::f both overrode \c A::f in the same subobject of
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/// type \c A, in this example the two virtual functions both override
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/// \c A::f but in *different* subobjects of type A. This is
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/// represented by numbering the subobjects in which the overridden
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/// and the overriding virtual member functions are located. Subobject
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/// 0 represents the virtual base class subobject of that type, while
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/// subobject numbers greater than 0 refer to non-virtual base class
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/// subobjects of that type.
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class CXXFinalOverriderMap
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  : public llvm::MapVector<const CXXMethodDecl *, OverridingMethods> {};
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/// A set of all the primary bases for a class.
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class CXXIndirectPrimaryBaseSet
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  : public llvm::SmallSet<const CXXRecordDecl*, 32> {};
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inline bool
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1.67k
inheritanceModelHasVBPtrOffsetField(MSInheritanceModel Inheritance) {
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1.67k
  return Inheritance == MSInheritanceModel::Unspecified;
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1.67k
}
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// Only member pointers to functions need a this adjustment, since it can be
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// combined with the field offset for data pointers.
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inline bool inheritanceModelHasNVOffsetField(bool IsMemberFunction,
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1.55k
                                             MSInheritanceModel Inheritance) {
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1.55k
  return IsMemberFunction && 
Inheritance >= MSInheritanceModel::Multiple1.17k
;
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1.55k
}
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inline bool
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1.76k
inheritanceModelHasVBTableOffsetField(MSInheritanceModel Inheritance) {
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1.76k
  return Inheritance >= MSInheritanceModel::Virtual;
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1.76k
}
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inline bool inheritanceModelHasOnlyOneField(bool IsMemberFunction,
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708
                                            MSInheritanceModel Inheritance) {
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708
  if (IsMemberFunction)
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    return Inheritance <= MSInheritanceModel::Single;
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  return Inheritance <= MSInheritanceModel::Multiple;
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}
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} // namespace clang
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#endif // LLVM_CLANG_AST_CXXINHERITANCE_H