1//===- BaseSubobject.h - BaseSubobject class --------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file provides a definition of the BaseSubobject class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_AST_BASESUBOBJECT_H
14#define LLVM_CLANG_AST_BASESUBOBJECT_H
15
16#include "clang/AST/CharUnits.h"
17#include "clang/AST/DeclCXX.h"
18#include "llvm/ADT/DenseMapInfo.h"
19#include "llvm/Support/type_traits.h"
20#include <cstdint>
21#include <utility>
22
23namespace clang {
24
25class CXXRecordDecl;
26
27// BaseSubobject - Uniquely identifies a direct or indirect base class.
28// Stores both the base class decl and the offset from the most derived class to
29// the base class. Used for vtable and VTT generation.
30class BaseSubobject {
31  /// Base - The base class declaration.
32  const CXXRecordDecl *Base;
33
34  /// BaseOffset - The offset from the most derived class to the base class.
35  CharUnits BaseOffset;
36
37public:
38  BaseSubobject() = default;
39  BaseSubobject(const CXXRecordDecl *Base, CharUnits BaseOffset)
40      : Base(Base), BaseOffset(BaseOffset) {}
41
42  /// getBase - Returns the base class declaration.
43  const CXXRecordDecl *getBase() const { return Base; }
44
45  /// getBaseOffset - Returns the base class offset.
46  CharUnits getBaseOffset() const { return BaseOffset; }
47
48  friend bool operator==(const BaseSubobject &LHS, const BaseSubobject &RHS) {
49    return LHS.Base == RHS.Base && LHS.BaseOffset == RHS.BaseOffset;
50 }
51};
52
53} // namespace clang
54
55namespace llvm {
56
57template<> struct DenseMapInfo<clang::BaseSubobject> {
58  static clang::BaseSubobject getEmptyKey() {
59    return clang::BaseSubobject(
60      DenseMapInfo<const clang::CXXRecordDecl *>::getEmptyKey(),
61      clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getEmptyKey()));
62  }
63
64  static clang::BaseSubobject getTombstoneKey() {
65    return clang::BaseSubobject(
66      DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
67      clang::CharUnits::fromQuantity(DenseMapInfo<int64_t>::getTombstoneKey()));
68  }
69
70  static unsigned getHashValue(const clang::BaseSubobject &Base) {
71    using PairTy = std::pair<const clang::CXXRecordDecl *, clang::CharUnits>;
72
73    return DenseMapInfo<PairTy>::getHashValue(PairTy(Base.getBase(),
74                                                     Base.getBaseOffset()));
75  }
76
77  static bool isEqual(const clang::BaseSubobject &LHS,
78                      const clang::BaseSubobject &RHS) {
79    return LHS == RHS;
80  }
81};
82
83} // namespace llvm
84
85#endif // LLVM_CLANG_AST_BASESUBOBJECT_H
86