empty-class-layout.cpp
2.85 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -Wno-inaccessible-base
// expected-no-diagnostics
#define SA(n, p) int a##n[(p) ? 1 : -1]
namespace Test0 {
struct A { int a; };
SA(0, sizeof(A) == 4);
struct B { };
SA(1, sizeof(B) == 1);
struct C : A, B { };
SA(2, sizeof(C) == 4);
struct D { };
struct E : D { };
struct F : E { };
struct G : E, F { };
SA(3, sizeof(G) == 2);
struct Empty { Empty(); };
struct I : Empty {
Empty e;
};
SA(4, sizeof(I) == 2);
struct J : Empty {
Empty e[2];
};
SA(5, sizeof(J) == 3);
template<int N> struct Derived : Empty, Derived<N - 1> {
};
template<> struct Derived<0> : Empty { };
struct S1 : virtual Derived<10> {
Empty e;
};
SA(6, sizeof(S1) == 24);
struct S2 : virtual Derived<10> {
Empty e[2];
};
SA(7, sizeof(S2) == 24);
struct S3 {
Empty e;
};
struct S4 : Empty, S3 {
};
SA(8, sizeof(S4) == 2);
struct S5 : S3, Empty {};
SA(9, sizeof(S5) == 2);
struct S6 : S5 { };
SA(10, sizeof(S6) == 2);
struct S7 : Empty {
void *v;
};
SA(11, sizeof(S7) == 8);
struct S8 : Empty, A {
};
SA(12, sizeof(S8) == 4);
}
namespace Test1 {
// Test that we don't try to place both A subobjects at offset 0.
struct A { };
class B { virtual void f(); };
class C : A, virtual B { };
struct D : virtual C { };
struct E : virtual A { };
class F : D, E { };
SA(0, sizeof(F) == 24);
}
namespace Test2 {
// Test that B::a isn't laid out at offset 0.
struct Empty { };
struct A : Empty { };
struct B : Empty {
A a;
};
SA(0, sizeof(B) == 2);
}
namespace Test3 {
// Test that B::a isn't laid out at offset 0.
struct Empty { };
struct A { Empty e; };
struct B : Empty { A a; };
SA(0, sizeof(B) == 2);
}
namespace Test4 {
// Test that C::Empty isn't laid out at offset 0.
struct Empty { };
struct A : Empty { };
struct B { A a; };
struct C : B, Empty { };
SA(0, sizeof(C) == 2);
}
namespace Test5 {
// Test that B::Empty isn't laid out at offset 0.
struct Empty { };
struct Field : virtual Empty { };
struct A {
Field f;
};
struct B : A, Empty { };
SA(0, sizeof(B) == 16);
}
namespace Test6 {
// Test that B::A isn't laid out at offset 0.
struct Empty { };
struct Field : virtual Empty { };
struct A {
Field f;
};
struct B : Empty, A { };
SA(0, sizeof(B) == 16);
}
namespace Test7 {
// Make sure we reserve enough space for both bases; PR11745.
struct Empty { };
struct Base1 : Empty { };
struct Base2 : Empty { };
struct Test : Base1, Base2 {
char c;
};
SA(0, sizeof(Test) == 2);
}
namespace Test8 {
// Test that type sugar doesn't make us incorrectly determine the size of an
// array of empty classes.
struct Empty1 {};
struct Empty2 {};
struct Empties : Empty1, Empty2 {};
typedef Empty1 Sugar[4];
struct A : Empty2, Empties {
// This must go at offset 2, because if it were at offset 0,
// V[0][1] would overlap Empties::Empty1.
Sugar V[1];
};
SA(0, sizeof(A) == 6);
}