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| Rev | Author | Line No. | Line |
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| 14 | pmbaty | 1 | //===----- Thunk.h - Declarations related to VTable Thunks ------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | /// |
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| 9 | /// \file |
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| 10 | /// Enums/classes describing THUNK related information about constructors, |
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| 11 | /// destructors and thunks. |
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| 12 | /// |
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| 13 | //===----------------------------------------------------------------------===// |
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| 14 | |||
| 15 | #ifndef LLVM_CLANG_BASIC_THUNK_H |
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| 16 | #define LLVM_CLANG_BASIC_THUNK_H |
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| 17 | |||
| 18 | #include <cstdint> |
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| 19 | #include <cstring> |
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| 20 | |||
| 21 | namespace clang { |
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| 22 | |||
| 23 | class CXXMethodDecl; |
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| 24 | |||
| 25 | /// A return adjustment. |
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| 26 | struct ReturnAdjustment { |
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| 27 | /// The non-virtual adjustment from the derived object to its |
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| 28 | /// nearest virtual base. |
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| 29 | int64_t NonVirtual; |
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| 30 | |||
| 31 | /// Holds the ABI-specific information about the virtual return |
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| 32 | /// adjustment, if needed. |
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| 33 | union VirtualAdjustment { |
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| 34 | // Itanium ABI |
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| 35 | struct { |
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| 36 | /// The offset (in bytes), relative to the address point |
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| 37 | /// of the virtual base class offset. |
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| 38 | int64_t VBaseOffsetOffset; |
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| 39 | } Itanium; |
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| 40 | |||
| 41 | // Microsoft ABI |
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| 42 | struct { |
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| 43 | /// The offset (in bytes) of the vbptr, relative to the beginning |
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| 44 | /// of the derived class. |
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| 45 | uint32_t VBPtrOffset; |
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| 46 | |||
| 47 | /// Index of the virtual base in the vbtable. |
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| 48 | uint32_t VBIndex; |
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| 49 | } Microsoft; |
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| 50 | |||
| 51 | VirtualAdjustment() { memset(this, 0, sizeof(*this)); } |
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| 52 | |||
| 53 | bool Equals(const VirtualAdjustment &Other) const { |
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| 54 | return memcmp(this, &Other, sizeof(Other)) == 0; |
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| 55 | } |
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| 56 | |||
| 57 | bool isEmpty() const { |
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| 58 | VirtualAdjustment Zero; |
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| 59 | return Equals(Zero); |
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| 60 | } |
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| 61 | |||
| 62 | bool Less(const VirtualAdjustment &RHS) const { |
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| 63 | return memcmp(this, &RHS, sizeof(RHS)) < 0; |
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| 64 | } |
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| 65 | } Virtual; |
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| 66 | |||
| 67 | ReturnAdjustment() : NonVirtual(0) {} |
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| 68 | |||
| 69 | bool isEmpty() const { return !NonVirtual && Virtual.isEmpty(); } |
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| 70 | |||
| 71 | friend bool operator==(const ReturnAdjustment &LHS, |
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| 72 | const ReturnAdjustment &RHS) { |
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| 73 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Equals(RHS.Virtual); |
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| 74 | } |
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| 75 | |||
| 76 | friend bool operator!=(const ReturnAdjustment &LHS, |
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| 77 | const ReturnAdjustment &RHS) { |
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| 78 | return !(LHS == RHS); |
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| 79 | } |
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| 80 | |||
| 81 | friend bool operator<(const ReturnAdjustment &LHS, |
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| 82 | const ReturnAdjustment &RHS) { |
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| 83 | if (LHS.NonVirtual < RHS.NonVirtual) |
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| 84 | return true; |
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| 85 | |||
| 86 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Less(RHS.Virtual); |
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| 87 | } |
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| 88 | }; |
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| 89 | |||
| 90 | /// A \c this pointer adjustment. |
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| 91 | struct ThisAdjustment { |
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| 92 | /// The non-virtual adjustment from the derived object to its |
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| 93 | /// nearest virtual base. |
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| 94 | int64_t NonVirtual; |
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| 95 | |||
| 96 | /// Holds the ABI-specific information about the virtual this |
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| 97 | /// adjustment, if needed. |
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| 98 | union VirtualAdjustment { |
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| 99 | // Itanium ABI |
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| 100 | struct { |
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| 101 | /// The offset (in bytes), relative to the address point, |
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| 102 | /// of the virtual call offset. |
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| 103 | int64_t VCallOffsetOffset; |
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| 104 | } Itanium; |
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| 105 | |||
| 106 | struct { |
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| 107 | /// The offset of the vtordisp (in bytes), relative to the ECX. |
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| 108 | int32_t VtordispOffset; |
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| 109 | |||
| 110 | /// The offset of the vbptr of the derived class (in bytes), |
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| 111 | /// relative to the ECX after vtordisp adjustment. |
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| 112 | int32_t VBPtrOffset; |
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| 113 | |||
| 114 | /// The offset (in bytes) of the vbase offset in the vbtable. |
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| 115 | int32_t VBOffsetOffset; |
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| 116 | } Microsoft; |
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| 117 | |||
| 118 | VirtualAdjustment() { memset(this, 0, sizeof(*this)); } |
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| 119 | |||
| 120 | bool Equals(const VirtualAdjustment &Other) const { |
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| 121 | return memcmp(this, &Other, sizeof(Other)) == 0; |
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| 122 | } |
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| 123 | |||
| 124 | bool isEmpty() const { |
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| 125 | VirtualAdjustment Zero; |
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| 126 | return Equals(Zero); |
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| 127 | } |
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| 128 | |||
| 129 | bool Less(const VirtualAdjustment &RHS) const { |
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| 130 | return memcmp(this, &RHS, sizeof(RHS)) < 0; |
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| 131 | } |
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| 132 | } Virtual; |
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| 133 | |||
| 134 | ThisAdjustment() : NonVirtual(0) {} |
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| 135 | |||
| 136 | bool isEmpty() const { return !NonVirtual && Virtual.isEmpty(); } |
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| 137 | |||
| 138 | friend bool operator==(const ThisAdjustment &LHS, const ThisAdjustment &RHS) { |
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| 139 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Equals(RHS.Virtual); |
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| 140 | } |
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| 141 | |||
| 142 | friend bool operator!=(const ThisAdjustment &LHS, const ThisAdjustment &RHS) { |
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| 143 | return !(LHS == RHS); |
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| 144 | } |
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| 145 | |||
| 146 | friend bool operator<(const ThisAdjustment &LHS, const ThisAdjustment &RHS) { |
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| 147 | if (LHS.NonVirtual < RHS.NonVirtual) |
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| 148 | return true; |
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| 149 | |||
| 150 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Less(RHS.Virtual); |
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| 151 | } |
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| 152 | }; |
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| 153 | |||
| 154 | /// The \c this pointer adjustment as well as an optional return |
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| 155 | /// adjustment for a thunk. |
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| 156 | struct ThunkInfo { |
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| 157 | /// The \c this pointer adjustment. |
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| 158 | ThisAdjustment This; |
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| 159 | |||
| 160 | /// The return adjustment. |
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| 161 | ReturnAdjustment Return; |
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| 162 | |||
| 163 | /// Holds a pointer to the overridden method this thunk is for, |
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| 164 | /// if needed by the ABI to distinguish different thunks with equal |
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| 165 | /// adjustments. Otherwise, null. |
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| 166 | /// CAUTION: In the unlikely event you need to sort ThunkInfos, consider using |
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| 167 | /// an ABI-specific comparator. |
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| 168 | const CXXMethodDecl *Method; |
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| 169 | |||
| 170 | ThunkInfo() : Method(nullptr) {} |
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| 171 | |||
| 172 | ThunkInfo(const ThisAdjustment &This, const ReturnAdjustment &Return, |
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| 173 | const CXXMethodDecl *Method = nullptr) |
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| 174 | : This(This), Return(Return), Method(Method) {} |
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| 175 | |||
| 176 | friend bool operator==(const ThunkInfo &LHS, const ThunkInfo &RHS) { |
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| 177 | return LHS.This == RHS.This && LHS.Return == RHS.Return && |
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| 178 | LHS.Method == RHS.Method; |
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| 179 | } |
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| 180 | |||
| 181 | bool isEmpty() const { |
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| 182 | return This.isEmpty() && Return.isEmpty() && Method == nullptr; |
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| 183 | } |
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| 184 | }; |
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| 185 | |||
| 186 | } // end namespace clang |
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| 187 | |||
| 188 | #endif |