warn-pessmizing-move.cpp
8.41 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
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
// RUN: %clang_cc1 -fsyntax-only -Wpessimizing-move -std=c++11 -verify %s
// RUN: %clang_cc1 -fsyntax-only -Wpessimizing-move -std=c++11 -verify %s -DUSER_DEFINED
// RUN: %clang_cc1 -fsyntax-only -Wpessimizing-move -std=c++11 -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
// definitions for std::move
namespace std {
inline namespace foo {
template <class T> struct remove_reference { typedef T type; };
template <class T> struct remove_reference<T&> { typedef T type; };
template <class T> struct remove_reference<T&&> { typedef T type; };
template <class T> typename remove_reference<T>::type &&move(T &&t);
}
}
struct A {
#ifdef USER_DEFINED
A() {}
A(const A &) {}
A(A &&) {}
A &operator=(const A &) { return *this; }
A &operator=(A &&) { return *this; }
#endif
};
struct B {
B() {}
B(A) {}
};
A test1(A a1) {
A a2;
return a1;
return a2;
return std::move(a1);
return std::move(a2);
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
}
B test2(A a1, B b1) {
// Object is different than return type so don't warn.
A a2;
return a1;
return a2;
return std::move(a1);
return std::move(a2);
B b2;
return b1;
return b2;
return std::move(b1);
return std::move(b2);
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
return A();
return test1(a2);
return std::move(A());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
return std::move(test1(a2));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:29-[[@LINE-4]]:30}:""
}
A global_a;
A test3() {
// Don't warn when object is not local.
return global_a;
return std::move(global_a);
static A static_a;
return static_a;
return std::move(static_a);
}
A test4() {
return A();
return test3();
return std::move(A());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
return std::move(test3());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:27-[[@LINE-4]]:28}:""
}
void test5(A) {
test5(A());
test5(test4());
test5(std::move(A()));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:9-[[@LINE-3]]:19}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
test5(std::move(test4()));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:9-[[@LINE-3]]:19}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:26-[[@LINE-4]]:27}:""
}
void test6() {
A a1 = A();
A a2 = test3();
A a3 = std::move(A());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
a3 = std::move(A());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:8-[[@LINE-3]]:18}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:21-[[@LINE-4]]:22}:""
A a4 = std::move(test3());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:27-[[@LINE-4]]:28}:""
a4 = std::move(test3());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:8-[[@LINE-3]]:18}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:25-[[@LINE-4]]:26}:""
}
A test7() {
A a1 = std::move(A());
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
A a2 = std::move((A()));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:25-[[@LINE-4]]:26}:""
A a3 = (std::move(A()));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:24-[[@LINE-4]]:25}:""
A a4 = (std::move((A())));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:26-[[@LINE-4]]:27}:""
return std::move(a1);
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
return std::move((a1));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:24-[[@LINE-4]]:25}:""
return (std::move(a1));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
return (std::move((a1)));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:25-[[@LINE-4]]:26}:""
}
#define wrap1(x) x
#define wrap2(x) x
// Macro test. Since the std::move call is outside the macro, it is
// safe to suggest a fix-it.
A test8() {
A a;
return std::move(a);
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:21-[[@LINE-4]]:22}:""
return std::move(wrap1(a));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:28-[[@LINE-4]]:29}:""
return std::move(wrap1(wrap2(a)));
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:35-[[@LINE-4]]:36}:""
}
#define test9 \
A test9() { \
A a; \
return std::move(a); \
}
// Macro test. The std::call is inside the macro, so no fix-it is suggested.
test9
// expected-warning@-1{{prevents copy elision}}
// CHECK-NOT: fix-it
#define return_a return std::move(a)
// Macro test. The std::call is inside the macro, so no fix-it is suggested.
A test10() {
A a;
return_a;
// expected-warning@-1{{prevents copy elision}}
// CHECK-NOT: fix-it
}
namespace templates {
struct A {};
struct B { B(A); };
// Warn once here since the type is not dependent.
template <typename T>
A test1() {
A a;
return std::move(a);
// expected-warning@-1{{prevents copy elision}}
// expected-note@-2{{remove std::move call}}
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:12-[[@LINE-3]]:22}:""
// CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
}
void run_test1() {
test1<A>();
test1<B>();
}
// T1 and T2 may not be the same, the warning may not always apply.
template <typename T1, typename T2>
T1 test2() {
T2 t;
return std::move(t);
}
void run_test2() {
test2<A, A>();
test2<B, A>();
}
}