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1 // RUN: %check_clang_tidy %s cppcoreguidelines-owning-memory %t
2 
3 namespace gsl {
4 template <class T>
5 using owner = T;
6 } // namespace gsl
7 
8 template <typename T>
9 class unique_ptr {
10 public:
unique_ptr(gsl::owner<T> resource)11   unique_ptr(gsl::owner<T> resource) : memory(resource) {}
12   unique_ptr(const unique_ptr<T> &) = default;
13 
~unique_ptr()14   ~unique_ptr() { delete memory; }
15 
16 private:
17   gsl::owner<T> memory;
18 };
19 
takes_owner(gsl::owner<int * > owned_int)20 void takes_owner(gsl::owner<int *> owned_int) {
21 }
22 
takes_pointer(int * unowned_int)23 void takes_pointer(int *unowned_int) {
24 }
25 
takes_owner_and_more(int some_int,gsl::owner<int * > owned_int,float f)26 void takes_owner_and_more(int some_int, gsl::owner<int *> owned_int, float f) {
27 }
28 
29 template <typename T>
takes_templated_owner(gsl::owner<T> owned_T)30 void takes_templated_owner(gsl::owner<T> owned_T) {
31 }
32 
returns_owner1()33 gsl::owner<int *> returns_owner1() { return gsl::owner<int *>(new int(42)); } // Ok
returns_owner2()34 gsl::owner<int *> returns_owner2() { return new int(42); }                    // Ok
35 
returns_no_owner1()36 int *returns_no_owner1() { return nullptr; }
returns_no_owner2()37 int *returns_no_owner2() {
38   return new int(42);
39   // CHECK-NOTES: [[@LINE-1]]:3: warning: returning a newly created resource of type 'int *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>'
40 }
returns_no_owner3()41 int *returns_no_owner3() {
42   int *should_be_owner = new int(42);
43   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
44   return should_be_owner;
45 }
returns_no_owner4()46 int *returns_no_owner4() {
47   gsl::owner<int *> owner = new int(42);
48   return owner;
49   // CHECK-NOTES: [[@LINE-1]]:3: warning: returning a newly created resource of type 'int *' or 'gsl::owner<>' from a function whose return type is not 'gsl::owner<>'
50 }
51 
returns_no_owner5()52 unique_ptr<int *> returns_no_owner5() {
53   return unique_ptr<int *>(new int(42)); // Ok
54 }
55 
56 /// FIXME: CSA finds it, but the report is misleading. Ownersemantics can catch this
57 /// by flow analysis similar to bugprone-use-after-move.
csa_not_finding_leak()58 void csa_not_finding_leak() {
59   gsl::owner<int *> o1 = new int(42); // Ok
60 
61   gsl::owner<int *> o2 = o1; // Ok
62   o2 = new int(45);          // conceptual leak, the memory from o1 is now leaked, since its considered moved in the guidelines
63 
64   delete o2;
65   // actual leak occurs here, its found, but mixed
66   delete o1;
67 }
68 
test_assignment_and_initialization()69 void test_assignment_and_initialization() {
70   int stack_int1 = 15;
71   int stack_int2;
72 
73   gsl::owner<int *> owned_int1 = &stack_int1; // BAD
74   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'int *'
75 
76   gsl::owner<int *> owned_int2;
77   owned_int2 = &stack_int2; // BAD since no owner, bad since uninitialized
78   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected assignment source to be of type 'gsl::owner<>'; got 'int *'
79 
80   gsl::owner<int *> owned_int3 = new int(42); // Good
81   owned_int3 = nullptr;                       // Good
82 
83   gsl::owner<int *> owned_int4(nullptr); // Ok
84   owned_int4 = new int(42);              // Good
85 
86   gsl::owner<int *> owned_int5 = owned_int3; // Good
87 
88   gsl::owner<int *> owned_int6{nullptr}; // Ok
89   owned_int6 = owned_int4;               // Good
90 
91   // FIXME:, flow analysis for the case of reassignment. Value must be released before
92   owned_int6 = owned_int3; // BAD, because reassignment without resource release
93 
94   auto owned_int7 = returns_owner1(); // Bad, since type deduction eliminates the owner wrapper
95   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
96   // CHECK-NOTES: [[@LINE-2]]:3: note: type deduction did not result in an owner
97 
98   const auto owned_int8 = returns_owner2(); // Bad, since type deduction eliminates the owner wrapper
99   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *const' with a newly created 'gsl::owner<>'
100   // CHECK-NOTES: [[@LINE-2]]:3: note: type deduction did not result in an owner
101 
102   gsl::owner<int *> owned_int9 = returns_owner1(); // Ok
103   int *unowned_int3 = returns_owner1();            // Bad
104   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
105 
106   gsl::owner<int *> owned_int10;
107   owned_int10 = returns_owner1(); // Ok
108 
109   int *unowned_int4;
110   unowned_int4 = returns_owner1(); // Bad
111   // CHECK-NOTES: [[@LINE-1]]:3: warning: assigning newly created 'gsl::owner<>' to non-owner 'int *'
112 
113   gsl::owner<int *> owned_int11 = returns_no_owner1(); // Bad since no owner
114   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'int *'
115 
116   gsl::owner<int *> owned_int12;
117   owned_int12 = returns_no_owner1(); // Bad since no owner
118   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected assignment source to be of type 'gsl::owner<>'; got 'int *'
119 
120   int *unowned_int5 = returns_no_owner1(); // Ok
121   int *unowned_int6;
122   unowned_int6 = returns_no_owner1(); // Ok
123 
124   int *unowned_int7 = new int(42); // Bad, since resource not assigned to an owner
125   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
126 
127   int *unowned_int8;
128   unowned_int8 = new int(42);
129   // CHECK-NOTES: [[@LINE-1]]:3: warning: assigning newly created 'gsl::owner<>' to non-owner 'int *'
130 
131   gsl::owner<int *> owned_int13 = nullptr; // Ok
132 }
133 
test_deletion()134 void test_deletion() {
135   gsl::owner<int *> owned_int1 = new int(42);
136   delete owned_int1; // Good
137 
138   gsl::owner<int *> owned_int2 = new int[42];
139   delete[] owned_int2; // Good
140 
141   int *unowned_int1 = new int(42); // BAD, since new creates and owner
142   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
143   delete unowned_int1; // BAD, since no owner
144   // CHECK-NOTES: [[@LINE-1]]:3: warning: deleting a pointer through a type that is not marked 'gsl::owner<>'; consider using a smart pointer instead
145   // CHECK-NOTES: [[@LINE-4]]:3: note: variable declared here
146 
147   int *unowned_int2 = new int[42]; // BAD, since new creates and owner
148   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'int *' with a newly created 'gsl::owner<>'
149   delete[] unowned_int2; // BAD since no owner
150   // CHECK-NOTES: [[@LINE-1]]:3: warning: deleting a pointer through a type that is not marked 'gsl::owner<>'; consider using a smart pointer instead
151   // CHECK-NOTES: [[@LINE-4]]:3: note: variable declared here
152 
153   delete new int(42);   // Technically ok, but stupid
154   delete[] new int[42]; // Technically ok, but stupid
155 }
156 
test_owner_function_calls()157 void test_owner_function_calls() {
158   int stack_int = 42;
159   int *unowned_int1 = &stack_int;
160   takes_owner(&stack_int); // BAD
161   // CHECK-NOTES: [[@LINE-1]]:15: warning: expected argument of type 'gsl::owner<>'; got 'int *'
162   takes_owner(unowned_int1); // BAD
163   // CHECK-NOTES: [[@LINE-1]]:15: warning: expected argument of type 'gsl::owner<>'; got 'int *'
164 
165   gsl::owner<int *> owned_int1 = new int(42);
166   takes_owner(owned_int1); // Ok
167 
168   takes_owner_and_more(42, &stack_int, 42.0f); // BAD
169   // CHECK-NOTES: [[@LINE-1]]:28: warning: expected argument of type 'gsl::owner<>'; got 'int *'
170   takes_owner_and_more(42, unowned_int1, 42.0f); // BAD
171   // CHECK-NOTES: [[@LINE-1]]:28: warning: expected argument of type 'gsl::owner<>'; got 'int *'
172 
173   takes_owner_and_more(42, new int(42), 42.0f); // Ok, since new is consumed by owner
174   takes_owner_and_more(42, owned_int1, 42.0f);  // Ok, since owner as argument
175 
176   takes_templated_owner(owned_int1);   // Ok
177   takes_templated_owner(new int(42));  // Ok
178   takes_templated_owner(unowned_int1); // Bad
179   // CHECK-NOTES: [[@LINE-1]]:25: warning: expected argument of type 'gsl::owner<>'; got 'int *'
180 
181   takes_owner(returns_owner1());    // Ok
182   takes_owner(returns_no_owner1()); // BAD
183   // CHECK-NOTES: [[@LINE-1]]:15: warning: expected argument of type 'gsl::owner<>'; got 'int *'
184 }
185 
test_unowned_function_calls()186 void test_unowned_function_calls() {
187   int stack_int = 42;
188   int *unowned_int1 = &stack_int;
189   gsl::owner<int *> owned_int1 = new int(42);
190 
191   takes_pointer(&stack_int);   // Ok
192   takes_pointer(unowned_int1); // Ok
193   takes_pointer(owned_int1);   // Ok
194   takes_pointer(new int(42));  // Bad, since new creates and owner
195   // CHECK-NOTES: [[@LINE-1]]:17: warning: initializing non-owner argument of type 'int *' with a newly created 'gsl::owner<>'
196 
197   takes_pointer(returns_owner1()); // Bad
198   // CHECK-NOTES: [[@LINE-1]]:17: warning: initializing non-owner argument of type 'int *' with a newly created 'gsl::owner<>'
199 
200   takes_pointer(returns_no_owner1()); // Ok
201 }
202 
203 // FIXME: Typedefing owner<> to something else does not work.
204 // This might be necessary for code already having a similar typedef like owner<> and
205 // replacing it with owner<>. This might be the same problem as with templates.
206 // The canonical type will ignore the owner<> alias, since its a typedef as well.
207 //
208 // Check, if owners hidden by typedef are handled the same as 'obvious' owners.
209 #if 0
210 using heap_int = gsl::owner<int *>;
211 typedef gsl::owner<float *> heap_float;
212 
213 // This tests only a subset, assuming that the check will either see through the
214 // typedef or not (it doesn't!).
215 void test_typedefed_values() {
216   // Modern typedef.
217   int StackInt1 = 42;
218   heap_int HeapInt1 = &StackInt1;
219   // CHECK MESSAGES: [[@LINE-1]]:3: warning: expected assignment source to be of type 'gsl::owner<>'; got 'int *'
220 
221   //FIXME: Typedef not considered correctly here.
222   // heap_int HeapInt2 = new int(42); // Ok
223   takes_pointer(HeapInt1); // Ok
224   takes_owner(HeapInt1);   // Ok
225 
226   // Traditional typedef.
227   float StackFloat1 = 42.0f;
228   heap_float HeapFloat1 = &StackFloat1;
229   // CHECK MESSAGES: [[@LINE-1]]:3: warning: expected assignment source to be of type 'gsl::owner<>'; got 'float *'
230 
231   //FIXME: Typedef not considered correctly here.
232   // heap_float HeapFloat2 = new float(42.0f);
233   HeapFloat2 = HeapFloat1; // Ok
234 }
235 #endif
236 
237 struct ArbitraryClass {};
238 struct ClassWithOwner {                    // Does not define destructor, necessary with owner
ClassWithOwnerClassWithOwner239   ClassWithOwner() : owner_var(nullptr) {} // Ok
240 
ClassWithOwnerClassWithOwner241   ClassWithOwner(ArbitraryClass &other) : owner_var(&other) {}
242   // CHECK-NOTES: [[@LINE-1]]:43: warning: expected initialization of owner member variable with value of type 'gsl::owner<>'; got 'ArbitraryClass *'
243 
ClassWithOwnerClassWithOwner244   ClassWithOwner(gsl::owner<ArbitraryClass *> other) : owner_var(other) {} // Ok
245 
ClassWithOwnerClassWithOwner246   ClassWithOwner(gsl::owner<ArbitraryClass *> data, int /* unused */) { // Ok
247     owner_var = data;                                                   // Ok
248   }
249 
ClassWithOwnerClassWithOwner250   ClassWithOwner(ArbitraryClass *bad_data, int /* unused */, int /* unused */) {
251     owner_var = bad_data;
252     // CHECK-NOTES: [[@LINE-1]]:5: warning: expected assignment source to be of type 'gsl::owner<>'; got 'ArbitraryClass *'
253   }
254 
ClassWithOwnerClassWithOwner255   ClassWithOwner(ClassWithOwner &&other) : owner_var{other.owner_var} {} // Ok
256 
operator =ClassWithOwner257   ClassWithOwner &operator=(ClassWithOwner &&other) {
258     owner_var = other.owner_var; // Ok
259     return *this;
260   }
261 
262   // Returning means, that the owner is "moved", so the class should not access this
263   // variable anymore after this method gets called.
buggy_but_returns_ownerClassWithOwner264   gsl::owner<ArbitraryClass *> buggy_but_returns_owner() { return owner_var; }
265 
266   gsl::owner<ArbitraryClass *> owner_var;
267   // CHECK-NOTES: [[@LINE-1]]:3: warning: member variable of type 'gsl::owner<>' requires the class 'ClassWithOwner' to implement a destructor to release the owned resource
268 };
269 
270 class DefaultedDestructor {         // Bad since default constructor with owner
271   ~DefaultedDestructor() = default; // Bad, since will not destroy the owner
272   gsl::owner<int *> Owner;
273   // CHECK-NOTES: [[@LINE-1]]:3: warning: member variable of type 'gsl::owner<>' requires the class 'DefaultedDestructor' to implement a destructor to release the owned resource
274 };
275 
276 struct DeletedDestructor {
277   ~DeletedDestructor() = delete;
278   gsl::owner<int *> Owner;
279   // CHECK-NOTES: [[@LINE-1]]:3: warning: member variable of type 'gsl::owner<>' requires the class 'DeletedDestructor' to implement a destructor to release the owned resource
280 };
281 
test_class_with_owner()282 void test_class_with_owner() {
283   ArbitraryClass A;
284   ClassWithOwner C1;                                                   // Ok
285   ClassWithOwner C2{A};                                                // Bad, since the owner would be initialized with an non-owner, but catched in the class
286   ClassWithOwner C3{gsl::owner<ArbitraryClass *>(new ArbitraryClass)}; // Ok
287 
288   const auto Owner1 = C3.buggy_but_returns_owner(); // BAD, deduces Owner1 to ArbitraryClass *const
289   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'ArbitraryClass *const' with a newly created 'gsl::owner<>'
290   // CHECK-NOTES: [[@LINE-2]]:3: note: type deduction did not result in an owner
291 
292   auto Owner2 = C2.buggy_but_returns_owner(); // BAD, deduces Owner2 to ArbitraryClass *
293   // CHECK-NOTES: [[@LINE-1]]:3: warning: initializing non-owner 'ArbitraryClass *' with a newly created 'gsl::owner<>'
294   // CHECK-NOTES: [[@LINE-2]]:3: note: type deduction did not result in an owner
295 
296   Owner2 = &A; // Ok, since type deduction did NOT result in owner<int*>
297 
298   gsl::owner<ArbitraryClass *> Owner3 = C1.buggy_but_returns_owner(); // Ok, still an owner
299   Owner3 = &A;                                                        // Bad, since assignment of non-owner to owner
300   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected assignment source to be of type 'gsl::owner<>'; got 'ArbitraryClass *'
301 }
302 
303 template <typename T>
304 struct HeapArray {                                          // Ok, since destructor with owner
HeapArrayHeapArray305   HeapArray() : _data(nullptr), size(0) {}                  // Ok
HeapArrayHeapArray306   HeapArray(int size) : _data(new int[size]), size(size) {} // Ok
HeapArrayHeapArray307   HeapArray(int size, T val) {
308     _data = new int[size]; // Ok
309     size = size;
310     for (auto i = 0u; i < size; ++i)
311       _data[i] = val; // Ok
312   }
HeapArrayHeapArray313   HeapArray(int size, T val, int *problematic) : _data{problematic}, size(size) {} // Bad
314   // CHECK-NOTES: [[@LINE-1]]:50: warning: expected initialization of owner member variable with value of type 'gsl::owner<>'; got 'void'
315   // FIXME: void is incorrect type, probably wrong thing matched
316 
HeapArrayHeapArray317   HeapArray(HeapArray &&other) : _data(other._data), size(other.size) { // Ok
318     other._data = nullptr;                                              // Ok
319     other.size = 0;
320   }
321 
operator =HeapArray322   HeapArray<T> &operator=(HeapArray<T> &&other) {
323     _data = other._data; // Ok, NOLINT warning here about bad types, why?
324     size = other.size;
325     return *this;
326   }
327 
~HeapArrayHeapArray328   ~HeapArray() { delete[] _data; } // Ok
329 
dataHeapArray330   T *data() { return _data; } // Ok NOLINT, because it "looks" like a factory
331 
332   gsl::owner<T *> _data;
333   unsigned int size;
334 };
335 
test_inner_template()336 void test_inner_template() {
337   HeapArray<int> Array1;
338   HeapArray<int> Array2(100);
339   HeapArray<int> Array3(100, 0);
340   HeapArray<int> Array4(100, 0, nullptr);
341 
342   Array1 = static_cast<HeapArray<int> &&>(Array2);
343   HeapArray<int> Array5(static_cast<HeapArray<int> &&>(Array3));
344 
345   int *NonOwningPtr = Array1.data();           // Ok
346   gsl::owner<int *> OwningPtr = Array1.data(); // Bad, since it does not return the owner
347   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'int *'
348 }
349 
350 // FIXME: Typededuction removes the owner - wrapper, therefore gsl::owner can not be used
351 // with Template classes like this. Is there a walkaround?
352 template <typename T>
353 struct TemplateValue {
354   TemplateValue() = default;
TemplateValueTemplateValue355   TemplateValue(T t) : val{t} {}
356 
setValTemplateValue357   void setVal(const T &t) { val = t; }
getValTemplateValue358   const T getVal() const { return val; }
359 
360   T val;
361 };
362 
363 // FIXME: Same typededcution problems
364 template <typename T>
template_function(T t)365 void template_function(T t) {
366   gsl::owner<int *> owner_t = t; // Probably bad, since type deduction still wrong
367   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'T'
368   // CHECK-NOTES: [[@LINE-2]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'int *'
369 }
370 
371 // FIXME: Same typededcution problems
test_templates()372 void test_templates() {
373   int stack_int = 42;
374   int *stack_ptr1 = &stack_int;
375 
376   TemplateValue<gsl::owner<int *>> Owner0; // Ok, T should be owner, but is int*
377 
378   TemplateValue<gsl::owner<int *>> Owner1(new int(42)); // Ok, T should be owner, but is int*
379   Owner1.setVal(&stack_int);                            // Bad since non-owner assignment
380   Owner1.setVal(stack_ptr1);                            // Bad since non-owner assignment
381   //Owner1.setVal(new int(42)); // Ok, but since type deduction is wrong, this one is considered harmful
382 
383   int *stack_ptr2 = Owner1.getVal(); // Bad, initializing non-owner with owner
384 
385   TemplateValue<int *> NonOwner1(new int(42));      // Bad, T is int *, hence dynamic memory to non-owner
386   gsl::owner<int *> IntOwner1 = NonOwner1.getVal(); // Bad, since owner initialized with non-owner
387   // CHECK-NOTES: [[@LINE-1]]:3: warning: expected initialization with value of type 'gsl::owner<>'; got 'int *'
388 
389   template_function(IntOwner1);  // Ok, but not actually ok, since type deduction removes owner
390   template_function(stack_ptr1); // Bad, but type deduction gets it wrong
391 }
392