1// RUN: %check_clang_tidy %s bugprone-sizeof-expression %t -- -config="{CheckOptions: {bugprone-sizeof-expression.WarnOnSizeOfIntegerExpression: true}}" --
2
3class C {
4 int size() { return sizeof(this); }
5 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(this)'
6};
7
8#define LEN 8
9
10int X;
11extern int A[10];
12extern short B[10];
13
14#pragma pack(1)
15struct S { char a, b, c; };
16
17enum E { E_VALUE = 0 };
18enum class EC { VALUE = 0 };
19
20bool AsBool() { return false; }
21int AsInt() { return 0; }
22E AsEnum() { return E_VALUE; }
23EC AsEnumClass() { return EC::VALUE; }
24S AsStruct() { return {}; }
25
26struct M {
27 int AsInt() { return 0; }
28 E AsEnum() { return E_VALUE; }
29 S AsStruct() { return {}; }
30};
31
32int ReturnOverload(int) { return {}; }
33S ReturnOverload(S) { return {}; }
34
35template <class T>
36T ReturnTemplate(T) { return {}; }
37
38template <class T>
39bool TestTrait1() {
40 return sizeof(ReturnOverload(T{})) == sizeof(A);
41}
42
43template <class T>
44bool TestTrait2() {
45 return sizeof(ReturnTemplate(T{})) == sizeof(A);
46}
47
48template <class T>
49bool TestTrait3() {
50 return sizeof(ReturnOverload(0)) == sizeof(T{});
51 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
52}
53
54template <class T>
55bool TestTrait4() {
56 return sizeof(ReturnTemplate(0)) == sizeof(T{});
57 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
58}
59
60bool TestTemplates() {
61 bool b = true;
62 b &= TestTrait1<int>();
63 b &= TestTrait1<S>();
64 b &= TestTrait2<int>();
65 b &= TestTrait2<S>();
66 b &= TestTrait3<int>();
67 b &= TestTrait3<S>();
68 b &= TestTrait4<int>();
69 b &= TestTrait4<S>();
70 return b;
71}
72
73int Test1(const char* ptr) {
74 int sum = 0;
75 sum += sizeof(LEN);
76 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(K)'
77 sum += sizeof(LEN + 1);
78 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(K)'
79 sum += sizeof(sum, LEN);
80 // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: suspicious usage of 'sizeof(..., ...)'
81 sum += sizeof(AsBool());
82 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
83 sum += sizeof(AsInt());
84 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
85 sum += sizeof(AsEnum());
86 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
87 sum += sizeof(AsEnumClass());
88 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
89 sum += sizeof(M{}.AsInt());
90 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
91 sum += sizeof(M{}.AsEnum());
92 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of integer type
93 sum += sizeof(sizeof(X));
94 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
95 sum += sizeof(LEN + sizeof(X));
96 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
97 sum += sizeof(LEN + LEN + sizeof(X));
98 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
99 sum += sizeof(LEN + (LEN + sizeof(X)));
100 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
101 sum += sizeof(LEN + -sizeof(X));
102 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
103 sum += sizeof(LEN + - + -sizeof(X));
104 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(sizeof(...))'
105 sum += sizeof(char) / sizeof(char);
106 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
107 sum += sizeof(A) / sizeof(S);
108 // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; numerator is not a multiple of denominator
109 sum += sizeof(char) / sizeof(int);
110 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; numerator is not a multiple of denominator
111 sum += sizeof(char) / sizeof(A);
112 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; numerator is not a multiple of denominator
113 sum += sizeof(B[0]) / sizeof(A);
114 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; numerator is not a multiple of denominator
115 sum += sizeof(ptr) / sizeof(char);
116 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; size of pointer is divided by size of pointed type
117 sum += sizeof(ptr) / sizeof(ptr[0]);
118 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; size of pointer is divided by size of pointed type
119 sum += sizeof(ptr) / sizeof(char*);
120 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have pointer types
121 sum += sizeof(ptr) / sizeof(void*);
122 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have pointer types
123 sum += sizeof(ptr) / sizeof(const void volatile*);
124 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have pointer types
125 sum += sizeof(ptr) / sizeof(char);
126 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; size of pointer is divided by size of pointed type
127 sum += sizeof(int) * sizeof(char);
128 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious 'sizeof' by 'sizeof' multiplication
129 sum += sizeof(ptr) * sizeof(ptr[0]);
130 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious 'sizeof' by 'sizeof' multiplication
131 sum += sizeof(int) * (2 * sizeof(char));
132 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious 'sizeof' by 'sizeof' multiplication
133 sum += (2 * sizeof(char)) * sizeof(int);
134 // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: suspicious 'sizeof' by 'sizeof' multiplication
135 if (sizeof(A) < 0x100000) sum += 42;
136 // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: suspicious comparison of 'sizeof(expr)' to a constant
137 if (sizeof(A) <= 0xFFFFFFFEU) sum += 42;
138 // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: suspicious comparison of 'sizeof(expr)' to a constant
139 return sum;
140}
141
142typedef char MyChar;
143typedef const MyChar MyConstChar;
144
145int CE0 = sizeof sizeof(char);
146// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: suspicious usage of 'sizeof(sizeof(...))'
147int CE1 = sizeof +sizeof(char);
148// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: suspicious usage of 'sizeof(sizeof(...))'
149int CE2 = sizeof sizeof(const char*);
150// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: suspicious usage of 'sizeof(sizeof(...))'
151int CE3 = sizeof sizeof(const volatile char* const*);
152// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: suspicious usage of 'sizeof(sizeof(...))'
153int CE4 = sizeof sizeof(MyConstChar);
154// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: suspicious usage of 'sizeof(sizeof(...))'
155
156int Test2(MyConstChar* A) {
157 int sum = 0;
158 sum += sizeof(MyConstChar) / sizeof(char);
159 // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
160 sum += sizeof(MyConstChar) / sizeof(MyChar);
161 // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
162 sum += sizeof(A[0]) / sizeof(char);
163 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
164 return sum;
165}
166
167template <int T>
168int Foo() { int A[T]; return sizeof(T); }
169// CHECK-MESSAGES: :[[@LINE-1]]:30: warning: suspicious usage of 'sizeof(K)'
170template <typename T>
171int Bar() { T A[5]; return sizeof(A[0]) / sizeof(T); }
172// CHECK-MESSAGES: :[[@LINE-1]]:41: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
173int Test3() { return Foo<42>() + Bar<char>(); }
174
175static const char* kABC = "abc";
176static const wchar_t* kDEF = L"def";
177int Test4(const char A[10]) {
178 int sum = 0;
179 sum += sizeof(kABC);
180 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(char*)'
181 sum += sizeof(kDEF);
182 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(char*)'
183 return sum;
184}
185
186int Test5() {
187 typedef int Array10[10];
188 typedef C ArrayC[10];
189
190 struct MyStruct {
191 Array10 arr;
192 Array10* ptr;
193 };
194 typedef const MyStruct TMyStruct;
195 typedef const MyStruct *PMyStruct;
196 typedef TMyStruct *PMyStruct2;
197
198 static TMyStruct kGlocalMyStruct = {};
199 static TMyStruct volatile * kGlocalMyStructPtr = &kGlocalMyStruct;
200
201 MyStruct S;
202 PMyStruct PS;
203 PMyStruct2 PS2;
204 Array10 A10;
205 C *PtrArray[10];
206 C *PC;
207
208 char *PChar;
209 int *PInt, **PPInt;
210 MyStruct **PPMyStruct;
211
212 int sum = 0;
213 sum += sizeof(&S.arr);
214 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
215 sum += sizeof(&kGlocalMyStruct.arr);
216 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
217 sum += sizeof(&kGlocalMyStructPtr->arr);
218 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
219 sum += sizeof(S.arr + 0);
220 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
221 sum += sizeof(+ S.arr);
222 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
223 sum += sizeof((int*)S.arr);
224 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
225
226 sum += sizeof(S.ptr);
227 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
228 sum += sizeof(kGlocalMyStruct.ptr);
229 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
230 sum += sizeof(kGlocalMyStructPtr->ptr);
231 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
232
233 sum += sizeof(&kGlocalMyStruct);
234 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
235 sum += sizeof(&S);
236 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
237 sum += sizeof(MyStruct*);
238 sum += sizeof(PMyStruct);
239 sum += sizeof(PS);
240 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
241 sum += sizeof(PS2);
242 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
243 sum += sizeof(&A10);
244 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
245 sum += sizeof(PtrArray) / sizeof(PtrArray[1]);
246 // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: suspicious usage of 'sizeof()' on an expression of pointer type
247 sum += sizeof(A10) / sizeof(PtrArray[0]);
248 sum += sizeof(PC) / sizeof(PtrArray[0]);
249 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof()' on an expression of pointer type
250 // CHECK-MESSAGES: :[[@LINE-2]]:21: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; both expressions have the same type
251 sum += sizeof(ArrayC) / sizeof(PtrArray[0]);
252 // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: suspicious usage of 'sizeof(...)/sizeof(...)'; numerator is not a multiple of denominator
253
254 // These pointers do not point to aggregate types, so they are not reported in this mode:
255 sum += sizeof(PChar);
256 sum += sizeof(PInt);
257 sum += sizeof(PPInt);
258 sum += sizeof(PPMyStruct);
259
260 return sum;
261}
262
263int Test6() {
264 int sum = 0;
265
266 struct S A = AsStruct(), B = AsStruct();
267 struct S *P = &A, *Q = &B;
268 sum += sizeof(struct S) == P - Q;
269 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
270 sum += 5 * sizeof(S) != P - Q;
271 // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
272 sum += sizeof(S) < P - Q;
273 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
274 sum += 5 * sizeof(S) <= P - Q;
275 // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
276 sum += 5 * sizeof(*P) >= P - Q;
277 // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
278 sum += Q - P > 3 * sizeof(*P);
279 // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
280 sum += sizeof(S) + (P - Q);
281 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
282 sum += 5 * sizeof(S) - (P - Q);
283 // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
284 sum += (P - Q) / sizeof(S);
285 // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
286 sum += (P - Q) / sizeof(*Q);
287 // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic
288
289 return sum;
290}
291
292static constexpr inline int BufferSize = 1024;
293
294template <typename T>
295T next(const T *&Read) {
296 T value = *Read;
297 Read += sizeof(T);
298 return value;
299}
300
301void Test7() {
302 int Buffer[BufferSize];
303 int *P = &Buffer[0];
304
305 const int *P2 = P;
306 int V1 = next(Read&: P2);
307 // CHECK-MESSAGES: :[[@LINE-10]]:8: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic; this scaled value will be scaled again by the '+=' operator
308 // CHECK-MESSAGES: :[[@LINE-11]]:8: note: '+=' in pointer arithmetic internally scales with 'sizeof(const int)' == {{[0-9]+}}
309 int V2 = next(Read&: P2);
310 (void)V1;
311 (void)V2;
312
313 int *Q = P;
314 while (Q < P + sizeof(Buffer)) {
315 // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: suspicious usage of 'sizeof(...)' in pointer arithmetic; this scaled value will be scaled again by the '+' operator
316 // CHECK-MESSAGES: :[[@LINE-2]]:16: note: '+' in pointer arithmetic internally scales with 'sizeof(int)' == {{[0-9]+}}
317 *Q++ = 0;
318 }
319}
320
321#ifdef __SIZEOF_INT128__
322template <__int128_t N>
323#else
324template <long N> // Fallback for platforms which do not define `__int128_t`
325#endif
326bool Baz() { return sizeof(A) < N; }
327// CHECK-MESSAGES: :[[@LINE-1]]:31: warning: suspicious comparison of 'sizeof(expr)' to a constant
328bool Test8() { return Baz<-1>(); }
329
330void some_generic_function(const void *arg, int argsize);
331int *IntP, **IntPP;
332C *ClassP, **ClassPP;
333
334void GenericFunctionTest() {
335 // The `sizeof(pointer)` checks ignore situations where the pointer is
336 // produced by dereferencing a pointer-to-pointer, because this is unlikely
337 // to be an accident and can appear in legitimate code that tries to call
338 // a generic function which emulates dynamic typing within C.
339 some_generic_function(arg: IntPP, argsize: sizeof(*IntPP));
340 some_generic_function(arg: ClassPP, argsize: sizeof(*ClassPP));
341 // Using `...[0]` instead of the dereference operator is another common
342 // variant, which is also widespread in the idiomatic array-size calculation:
343 // `sizeof(array) / sizeof(array[0])`.
344 some_generic_function(arg: IntPP, argsize: sizeof(IntPP[0]));
345 some_generic_function(arg: ClassPP, argsize: sizeof(ClassPP[0]));
346 // FIXME: There is a third common pattern where the generic function is
347 // called with `&Variable` and `sizeof(Variable)`. Right now these are
348 // reported by the `sizeof(pointer)` checks, but this causes some false
349 // positives, so it would be good to create an exception for them.
350 // NOTE: `sizeof(IntP)` is only reported with `WarnOnSizeOfPointer=true`.
351 some_generic_function(arg: &IntPP, argsize: sizeof(IntP));
352 some_generic_function(arg: &ClassPP, argsize: sizeof(ClassP));
353 // CHECK-MESSAGES: :[[@LINE-1]]:35: warning: suspicious usage of 'sizeof()' on an expression of pointer type
354}
355
356int ValidExpressions() {
357 int A[] = {1, 2, 3, 4};
358 static const char str[] = "hello";
359 static const char* ptr[] { "aaa", "bbb", "ccc" };
360 typedef C *CA10[10];
361 C *PtrArray[10];
362 CA10 PtrArray1;
363
364 int sum = 0;
365 if (sizeof(A) < 10)
366 sum += sizeof(A);
367 sum += sizeof(int);
368 sum += sizeof(AsStruct());
369 sum += sizeof(M{}.AsStruct());
370 sum += sizeof(A[sizeof(A) / sizeof(int)]);
371 sum += sizeof(&A[sizeof(A) / sizeof(int)]);
372 sum += sizeof(sizeof(0)); // Special case: sizeof size_t.
373 sum += sizeof(void*);
374 sum += sizeof(void const *);
375 sum += sizeof(void const *) / 4;
376 sum += sizeof(str);
377 sum += sizeof(str) / sizeof(char);
378 sum += sizeof(str) / sizeof(str[0]);
379 sum += sizeof(ptr) / sizeof(ptr[0]);
380 sum += sizeof(ptr) / sizeof(*(ptr));
381 sum += sizeof(PtrArray) / sizeof(PtrArray[0]);
382 // Canonical type of PtrArray1 is same as PtrArray.
383 sum = sizeof(PtrArray) / sizeof(PtrArray1[0]);
384 // There is no warning for 'sizeof(T*)/sizeof(Q)' case.
385 sum += sizeof(PtrArray) / sizeof(A[0]);
386 return sum;
387}
388
389namespace gh115175 {
390template<class T>
391int ValidateTemplateTypeExpressions(T t) {
392 return sizeof(t.val) / sizeof(t.val[0]);
393}
394} // namespace gh115175
395

source code of clang-tools-extra/test/clang-tidy/checkers/bugprone/sizeof-expression.cpp