1 | //===----- ABI.h - ABI related declarations ---------------------*- 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 | /// \file |
10 | /// Enums/classes describing ABI related information about constructors, |
11 | /// destructors and thunks. |
12 | /// |
13 | //===----------------------------------------------------------------------===// |
14 | |
15 | #ifndef LLVM_CLANG_BASIC_ABI_H |
16 | #define LLVM_CLANG_BASIC_ABI_H |
17 | |
18 | #include "llvm/Support/DataTypes.h" |
19 | #include <cstring> |
20 | |
21 | namespace clang { |
22 | |
23 | /// C++ constructor types. |
24 | enum CXXCtorType { |
25 | Ctor_Complete, ///< Complete object ctor |
26 | Ctor_Base, ///< Base object ctor |
27 | Ctor_Comdat, ///< The COMDAT used for ctors |
28 | Ctor_CopyingClosure, ///< Copying closure variant of a ctor |
29 | Ctor_DefaultClosure, ///< Default closure variant of a ctor |
30 | }; |
31 | |
32 | /// C++ destructor types. |
33 | enum CXXDtorType { |
34 | Dtor_Deleting, ///< Deleting dtor |
35 | Dtor_Complete, ///< Complete object dtor |
36 | Dtor_Base, ///< Base object dtor |
37 | Dtor_Comdat ///< The COMDAT used for dtors |
38 | }; |
39 | |
40 | /// A return adjustment. |
41 | struct ReturnAdjustment { |
42 | /// The non-virtual adjustment from the derived object to its |
43 | /// nearest virtual base. |
44 | int64_t NonVirtual; |
45 | |
46 | /// Holds the ABI-specific information about the virtual return |
47 | /// adjustment, if needed. |
48 | union VirtualAdjustment { |
49 | // Itanium ABI |
50 | struct { |
51 | /// The offset (in bytes), relative to the address point |
52 | /// of the virtual base class offset. |
53 | int64_t VBaseOffsetOffset; |
54 | } Itanium; |
55 | |
56 | // Microsoft ABI |
57 | struct { |
58 | /// The offset (in bytes) of the vbptr, relative to the beginning |
59 | /// of the derived class. |
60 | uint32_t VBPtrOffset; |
61 | |
62 | /// Index of the virtual base in the vbtable. |
63 | uint32_t VBIndex; |
64 | } Microsoft; |
65 | |
66 | VirtualAdjustment() { |
67 | memset(this, 0, sizeof(*this)); |
68 | } |
69 | |
70 | bool Equals(const VirtualAdjustment &Other) const { |
71 | return memcmp(this, &Other, sizeof(Other)) == 0; |
72 | } |
73 | |
74 | bool isEmpty() const { |
75 | VirtualAdjustment Zero; |
76 | return Equals(Zero); |
77 | } |
78 | |
79 | bool Less(const VirtualAdjustment &RHS) const { |
80 | return memcmp(this, &RHS, sizeof(RHS)) < 0; |
81 | } |
82 | } Virtual; |
83 | |
84 | ReturnAdjustment() : NonVirtual(0) {} |
85 | |
86 | bool isEmpty() const { return !NonVirtual && Virtual.isEmpty(); } |
87 | |
88 | friend bool operator==(const ReturnAdjustment &LHS, |
89 | const ReturnAdjustment &RHS) { |
90 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Equals(RHS.Virtual); |
91 | } |
92 | |
93 | friend bool operator!=(const ReturnAdjustment &LHS, const ReturnAdjustment &RHS) { |
94 | return !(LHS == RHS); |
95 | } |
96 | |
97 | friend bool operator<(const ReturnAdjustment &LHS, |
98 | const ReturnAdjustment &RHS) { |
99 | if (LHS.NonVirtual < RHS.NonVirtual) |
100 | return true; |
101 | |
102 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Less(RHS.Virtual); |
103 | } |
104 | }; |
105 | |
106 | /// A \c this pointer adjustment. |
107 | struct ThisAdjustment { |
108 | /// The non-virtual adjustment from the derived object to its |
109 | /// nearest virtual base. |
110 | int64_t NonVirtual; |
111 | |
112 | /// Holds the ABI-specific information about the virtual this |
113 | /// adjustment, if needed. |
114 | union VirtualAdjustment { |
115 | // Itanium ABI |
116 | struct { |
117 | /// The offset (in bytes), relative to the address point, |
118 | /// of the virtual call offset. |
119 | int64_t VCallOffsetOffset; |
120 | } Itanium; |
121 | |
122 | struct { |
123 | /// The offset of the vtordisp (in bytes), relative to the ECX. |
124 | int32_t VtordispOffset; |
125 | |
126 | /// The offset of the vbptr of the derived class (in bytes), |
127 | /// relative to the ECX after vtordisp adjustment. |
128 | int32_t VBPtrOffset; |
129 | |
130 | /// The offset (in bytes) of the vbase offset in the vbtable. |
131 | int32_t VBOffsetOffset; |
132 | } Microsoft; |
133 | |
134 | VirtualAdjustment() { |
135 | memset(this, 0, sizeof(*this)); |
136 | } |
137 | |
138 | bool Equals(const VirtualAdjustment &Other) const { |
139 | return memcmp(this, &Other, sizeof(Other)) == 0; |
140 | } |
141 | |
142 | bool isEmpty() const { |
143 | VirtualAdjustment Zero; |
144 | return Equals(Zero); |
145 | } |
146 | |
147 | bool Less(const VirtualAdjustment &RHS) const { |
148 | return memcmp(this, &RHS, sizeof(RHS)) < 0; |
149 | } |
150 | } Virtual; |
151 | |
152 | ThisAdjustment() : NonVirtual(0) { } |
153 | |
154 | bool isEmpty() const { return !NonVirtual && Virtual.isEmpty(); } |
155 | |
156 | friend bool operator==(const ThisAdjustment &LHS, |
157 | const ThisAdjustment &RHS) { |
158 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Equals(RHS.Virtual); |
159 | } |
160 | |
161 | friend bool operator!=(const ThisAdjustment &LHS, const ThisAdjustment &RHS) { |
162 | return !(LHS == RHS); |
163 | } |
164 | |
165 | friend bool operator<(const ThisAdjustment &LHS, |
166 | const ThisAdjustment &RHS) { |
167 | if (LHS.NonVirtual < RHS.NonVirtual) |
168 | return true; |
169 | |
170 | return LHS.NonVirtual == RHS.NonVirtual && LHS.Virtual.Less(RHS.Virtual); |
171 | } |
172 | }; |
173 | |
174 | class CXXMethodDecl; |
175 | |
176 | /// The \c this pointer adjustment as well as an optional return |
177 | /// adjustment for a thunk. |
178 | struct ThunkInfo { |
179 | /// The \c this pointer adjustment. |
180 | ThisAdjustment This; |
181 | |
182 | /// The return adjustment. |
183 | ReturnAdjustment Return; |
184 | |
185 | /// Holds a pointer to the overridden method this thunk is for, |
186 | /// if needed by the ABI to distinguish different thunks with equal |
187 | /// adjustments. Otherwise, null. |
188 | /// CAUTION: In the unlikely event you need to sort ThunkInfos, consider using |
189 | /// an ABI-specific comparator. |
190 | const CXXMethodDecl *Method; |
191 | |
192 | ThunkInfo() : Method(nullptr) { } |
193 | |
194 | ThunkInfo(const ThisAdjustment &This, const ReturnAdjustment &Return, |
195 | const CXXMethodDecl *Method = nullptr) |
196 | : This(This), Return(Return), Method(Method) {} |
197 | |
198 | friend bool operator==(const ThunkInfo &LHS, const ThunkInfo &RHS) { |
199 | return LHS.This == RHS.This && LHS.Return == RHS.Return && |
200 | LHS.Method == RHS.Method; |
201 | } |
202 | |
203 | bool isEmpty() const { |
204 | return This.isEmpty() && Return.isEmpty() && Method == nullptr; |
205 | } |
206 | }; |
207 | |
208 | } // end namespace clang |
209 | |
210 | #endif |
211 | |