1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wimplicit-fallthrough %s
2
3
fallthrough(int n)4 int fallthrough(int n) {
5 switch (n / 10) {
6 if (n - 1) {
7 n = 100;
8 } else if (n - 2) {
9 n = 101;
10 } else if (n - 3) {
11 n = 102;
12 }
13 case -1: // no warning here, ignore fall-through from unreachable code
14 ;
15 case 0: {// expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
16 }
17 case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
18 n += 100 ;
19 case 3: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
20 if (n > 0)
21 n += 200;
22 case 4: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
23 if (n < 0)
24 ;
25 case 5: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
26 switch (n) {
27 case 111:
28 break;
29 case 112:
30 break;
31 case 113:
32 break ;
33 }
34 case 6: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
35 n += 300;
36 case 66: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'break;' to avoid fall-through}}
37 case 67:
38 case 68:
39 break;
40 }
41 switch (n / 15) {
42 label_default:
43 default:
44 n += 333;
45 if (n % 10)
46 goto label_default;
47 break;
48 case 70:
49 n += 335;
50 break;
51 }
52 switch (n / 20) {
53 case 7:
54 n += 400;
55 [[clang::fallthrough]];
56 case 9: // no warning here, intended fall-through marked with an attribute
57 n += 800;
58 [[clang::fallthrough]];
59 default: { // no warning here, intended fall-through marked with an attribute
60 if (n % 2 == 0) {
61 return 1;
62 } else {
63 [[clang::fallthrough]];
64 }
65 }
66 case 10: // no warning here, intended fall-through marked with an attribute
67 if (n % 3 == 0) {
68 n %= 3;
69 } else {
70 [[clang::fallthrough]];
71 }
72 case 110: // expected-warning{{unannotated fall-through between switch labels}} but no fix-it hint as we have one fall-through annotation!
73 n += 800;
74 }
75 switch (n / 30) {
76 case 11:
77 case 12: // no warning here, intended fall-through, no statement between labels
78 n += 1600;
79 }
80 switch (n / 40) {
81 case 13:
82 if (n % 2 == 0) {
83 return 1;
84 } else {
85 return 2;
86 }
87 case 15: // no warning here, there's no fall-through
88 n += 3200;
89 }
90 switch (n / 50) {
91 case 17: {
92 if (n % 2 == 0) {
93 return 1;
94 } else {
95 return 2;
96 }
97 }
98 case 19: { // no warning here, there's no fall-through
99 n += 6400;
100 return 3;
101 }
102 case 21: { // no warning here, there's no fall-through
103 break;
104 }
105 case 23: // no warning here, there's no fall-through
106 n += 128000;
107 break;
108 case 25: // no warning here, there's no fall-through
109 break;
110 }
111
112 return n;
113 }
114
115 class ClassWithDtor {
116 public:
~ClassWithDtor()117 ~ClassWithDtor() {}
118 };
119
fallthrough2(int n)120 void fallthrough2(int n) {
121 switch (n) {
122 case 0:
123 {
124 ClassWithDtor temp;
125 break;
126 }
127 default: // no warning here, there's no fall-through
128 break;
129 }
130 }
131
fallthrough3(int n)132 void fallthrough3(int n) {
133 switch (n) {
134 case 1:
135 do {
136 return;
137 } while (0);
138 case 2:
139 do {
140 ClassWithDtor temp;
141 return;
142 } while (0);
143 case 3:
144 break;
145 }
146 }
147
148 #define MY_SWITCH(X, Y, Z, U, V) switch (X) { case Y: Z; case U: V; }
149 #define MY_SWITCH2(X, Y, Z) switch (X) { Y; Z; }
150 #define MY_CASE(X, Y) case X: Y
151 #define MY_CASE2(X, Y, U, V) case X: Y; case U: V
152
fallthrough_macro1(int n)153 int fallthrough_macro1(int n) {
154 MY_SWITCH(n, 13, n *= 2, 14, break) // expected-warning{{unannotated fall-through between switch labels}}
155
156 switch (n + 1) {
157 MY_CASE(33, n += 2);
158 MY_CASE(44, break); // expected-warning{{unannotated fall-through between switch labels}}
159 MY_CASE(55, n += 3);
160 }
161
162 switch (n + 3) {
163 MY_CASE(333, return 333);
164 MY_CASE2(444, n += 44, 4444, break); // expected-warning{{unannotated fall-through between switch labels}}
165 MY_CASE(555, n += 33);
166 }
167
168 MY_SWITCH2(n + 4, MY_CASE(17, n *= 3), MY_CASE(19, break)) // expected-warning{{unannotated fall-through between switch labels}}
169
170 MY_SWITCH2(n + 5, MY_CASE(21, break), MY_CASE2(23, n *= 7, 25, break)) // expected-warning{{unannotated fall-through between switch labels}}
171
172 return n;
173 }
174
fallthrough_cfgblock_with_null_successor(int x)175 void fallthrough_cfgblock_with_null_successor(int x) {
176 (x && "") ? (void)(0) : (void)(1);
177 switch (x) {}
178 }
179
fallthrough_position(int n)180 int fallthrough_position(int n) {
181 switch (n) {
182 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
183 n += 300;
184 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
185 case 221:
186 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
187 return 1;
188 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
189 case 222:
190 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
191 n += 400;
192 case 223: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
193 [[clang::fallthrough]]; // expected-warning{{fallthrough annotation does not directly precede switch label}}
194 }
195
196 long p = static_cast<long>(n) * n;
197 switch (sizeof(p)) {
198 case 9:
199 n += static_cast<int>(p >> 32);
200 [[clang::fallthrough]]; // no warning here
201 case 5:
202 n += static_cast<int>(p);
203 [[clang::fallthrough]]; // no warning here
204 default:
205 n += 1;
206 break;
207 }
208
209 return n;
210 }
211
212 enum Enum {
213 Value1, Value2
214 };
215
fallthrough_covered_enums(Enum e)216 int fallthrough_covered_enums(Enum e) {
217 int n = 0;
218 switch (e) {
219 default:
220 n += 17;
221 [[clang::fallthrough]]; // no warning here, this shouldn't be treated as unreachable code
222 case Value1:
223 n += 19;
224 break;
225 case Value2:
226 n += 21;
227 break;
228 }
229 return n;
230 }
231
232 // Fallthrough annotations in local classes used to generate "fallthrough
233 // annotation does not directly precede switch label" warning.
fallthrough_in_local_class()234 void fallthrough_in_local_class() {
235 class C {
236 void f(int x) {
237 switch (x) {
238 case 0:
239 x++;
240 [[clang::fallthrough]]; // no diagnostics
241 case 1:
242 x++;
243 default: // \
244 expected-warning{{unannotated fall-through between switch labels}} \
245 expected-note{{insert 'break;' to avoid fall-through}}
246 break;
247 }
248 }
249 };
250 }
251
252 // Fallthrough annotations in lambdas used to generate "fallthrough
253 // annotation does not directly precede switch label" warning.
fallthrough_in_lambda()254 void fallthrough_in_lambda() {
255 (void)[] {
256 int x = 0;
257 switch (x) {
258 case 0:
259 x++;
260 [[clang::fallthrough]]; // no diagnostics
261 case 1:
262 x++;
263 default: // \
264 expected-warning{{unannotated fall-through between switch labels}} \
265 expected-note{{insert 'break;' to avoid fall-through}}
266 break;
267 }
268 };
269 }
270
271 namespace PR18983 {
272 void fatal() __attribute__((noreturn));
273 int num();
test()274 void test() {
275 switch (num()) {
276 case 1:
277 fatal();
278 // Don't issue a warning.
279 case 2:
280 break;
281 }
282 }
283 }
284
fallthrough_targets(int n)285 int fallthrough_targets(int n) {
286 [[clang::fallthrough]]; // expected-error{{fallthrough annotation is outside switch statement}}
287
288 [[clang::fallthrough]] // expected-error{{fallthrough attribute is only allowed on empty statements}}
289 switch (n) {
290 case 121:
291 n += 400;
292 [[clang::fallthrough]]; // no warning here, correct target
293 case 123:
294 [[clang::fallthrough]] // expected-error{{fallthrough attribute is only allowed on empty statements}}
295 n += 800;
296 break;
297 [[clang::fallthrough]] // expected-error{{fallthrough attribute is only allowed on empty statements}} expected-note{{did you forget ';'?}}
298 case 125:
299 n += 1600;
300 }
301 return n;
302 }
303