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757bf1df | 1 | /* A state machine for detecting misuses of the malloc/free API. |
83ffe9cd | 2 | Copyright (C) 2019-2023 Free Software Foundation, Inc. |
757bf1df DM |
3 | Contributed by David Malcolm <dmalcolm@redhat.com>. |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING3. If not see | |
19 | <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #include "config.h" | |
6341f14e | 22 | #define INCLUDE_MEMORY |
757bf1df DM |
23 | #include "system.h" |
24 | #include "coretypes.h" | |
6341f14e | 25 | #include "make-unique.h" |
757bf1df DM |
26 | #include "tree.h" |
27 | #include "function.h" | |
28 | #include "basic-block.h" | |
29 | #include "gimple.h" | |
30 | #include "options.h" | |
31 | #include "bitmap.h" | |
32 | #include "diagnostic-path.h" | |
33 | #include "diagnostic-metadata.h" | |
757bf1df DM |
34 | #include "analyzer/analyzer.h" |
35 | #include "diagnostic-event-id.h" | |
36 | #include "analyzer/analyzer-logging.h" | |
37 | #include "analyzer/sm.h" | |
38 | #include "analyzer/pending-diagnostic.h" | |
808f4dfe DM |
39 | #include "analyzer/call-string.h" |
40 | #include "analyzer/program-point.h" | |
41 | #include "analyzer/store.h" | |
42 | #include "analyzer/region-model.h" | |
861c917a | 43 | #include "analyzer/call-details.h" |
c7e276b8 DM |
44 | #include "stringpool.h" |
45 | #include "attribs.h" | |
cd323d97 | 46 | #include "analyzer/function-set.h" |
eafa9d96 | 47 | #include "analyzer/program-state.h" |
0d6f7b1d DM |
48 | #include "analyzer/checker-event.h" |
49 | #include "analyzer/exploded-graph.h" | |
757bf1df DM |
50 | |
51 | #if ENABLE_ANALYZER | |
52 | ||
75038aa6 DM |
53 | namespace ana { |
54 | ||
757bf1df DM |
55 | namespace { |
56 | ||
c7e276b8 DM |
57 | /* This state machine and its various support classes track allocations |
58 | and deallocations. | |
59 | ||
60 | It has a few standard allocation/deallocation pairs (e.g. new/delete), | |
61 | and also supports user-defined ones via | |
62 | __attribute__ ((malloc(DEALLOCATOR))). | |
63 | ||
64 | There can be more than one valid deallocator for a given allocator, | |
65 | for example: | |
66 | __attribute__ ((malloc (fclose))) | |
67 | __attribute__ ((malloc (freopen, 3))) | |
68 | FILE* fopen (const char*, const char*); | |
69 | A deallocator_set represents a particular set of valid deallocators. | |
70 | ||
71 | We track the expected deallocator_set for a value, but not the allocation | |
72 | function - there could be more than one allocator per deallocator_set. | |
73 | For example, there could be dozens of allocators for "free" beyond just | |
74 | malloc e.g. calloc, xstrdup, etc. We don't want to explode the number | |
75 | of states by tracking individual allocators in the exploded graph; | |
76 | we merely want to track "this value expects to have 'free' called on it". | |
77 | Perhaps we can reconstruct which allocator was used later, when emitting | |
78 | the path, if it's necessary for precision of wording of diagnostics. */ | |
79 | ||
80 | class deallocator; | |
81 | class deallocator_set; | |
1690a839 DM |
82 | class malloc_state_machine; |
83 | ||
84 | /* An enum for discriminating between different kinds of allocation_state. */ | |
85 | ||
86 | enum resource_state | |
87 | { | |
c7e276b8 | 88 | /* States that are independent of allocator/deallocator. */ |
1690a839 DM |
89 | |
90 | /* The start state. */ | |
91 | RS_START, | |
92 | ||
5c6546ca DM |
93 | /* State for a pointer that's been unconditionally dereferenced. */ |
94 | RS_ASSUMED_NON_NULL, | |
95 | ||
1690a839 DM |
96 | /* State for a pointer that's known to be NULL. */ |
97 | RS_NULL, | |
98 | ||
99 | /* State for a pointer that's known to not be on the heap (e.g. to a local | |
100 | or global). */ | |
101 | RS_NON_HEAP, | |
102 | ||
103 | /* Stop state, for pointers we don't want to track any more. */ | |
104 | RS_STOP, | |
105 | ||
c7e276b8 | 106 | /* States that relate to a specific deallocator_set. */ |
1690a839 | 107 | |
c7e276b8 | 108 | /* State for a pointer returned from an allocator that hasn't |
1690a839 DM |
109 | been checked for NULL. |
110 | It could be a pointer to heap-allocated memory, or could be NULL. */ | |
111 | RS_UNCHECKED, | |
112 | ||
c7e276b8 | 113 | /* State for a pointer returned from an allocator, |
1690a839 DM |
114 | known to be non-NULL. */ |
115 | RS_NONNULL, | |
116 | ||
c7e276b8 | 117 | /* State for a pointer passed to a deallocator. */ |
1690a839 DM |
118 | RS_FREED |
119 | }; | |
120 | ||
c7e276b8 DM |
121 | /* Custom state subclass, which can optionally refer to an a |
122 | deallocator_set. */ | |
1690a839 DM |
123 | |
124 | struct allocation_state : public state_machine::state | |
125 | { | |
126 | allocation_state (const char *name, unsigned id, | |
c7e276b8 DM |
127 | enum resource_state rs, |
128 | const deallocator_set *deallocators, | |
129 | const deallocator *deallocator) | |
130 | : state (name, id), m_rs (rs), | |
131 | m_deallocators (deallocators), | |
132 | m_deallocator (deallocator) | |
1690a839 DM |
133 | {} |
134 | ||
5c6546ca | 135 | void dump_to_pp (pretty_printer *pp) const override; |
1690a839 DM |
136 | |
137 | const allocation_state *get_nonnull () const; | |
138 | ||
139 | enum resource_state m_rs; | |
c7e276b8 DM |
140 | const deallocator_set *m_deallocators; |
141 | const deallocator *m_deallocator; | |
1690a839 DM |
142 | }; |
143 | ||
5c6546ca DM |
144 | /* Custom state subclass, for the "assumed-non-null" state |
145 | where the assumption happens in a particular frame. */ | |
146 | ||
147 | struct assumed_non_null_state : public allocation_state | |
148 | { | |
149 | assumed_non_null_state (const char *name, unsigned id, | |
150 | const frame_region *frame) | |
151 | : allocation_state (name, id, RS_ASSUMED_NON_NULL, | |
152 | NULL, NULL), | |
153 | m_frame (frame) | |
154 | { | |
155 | gcc_assert (m_frame); | |
156 | } | |
157 | ||
158 | void dump_to_pp (pretty_printer *pp) const final override; | |
159 | ||
160 | const frame_region *m_frame; | |
161 | }; | |
162 | ||
1690a839 DM |
163 | /* An enum for choosing which wording to use in various diagnostics |
164 | when describing deallocations. */ | |
165 | ||
166 | enum wording | |
167 | { | |
168 | WORDING_FREED, | |
c7e276b8 | 169 | WORDING_DELETED, |
a6baafca DM |
170 | WORDING_DEALLOCATED, |
171 | WORDING_REALLOCATED | |
1690a839 DM |
172 | }; |
173 | ||
c7e276b8 DM |
174 | /* Base class representing a deallocation function, |
175 | either a built-in one we know about, or one exposed via | |
176 | __attribute__((malloc(DEALLOCATOR))). */ | |
1690a839 | 177 | |
c7e276b8 | 178 | struct deallocator |
1690a839 | 179 | { |
c7e276b8 DM |
180 | hashval_t hash () const; |
181 | void dump_to_pp (pretty_printer *pp) const; | |
182 | static int cmp (const deallocator *a, const deallocator *b); | |
183 | static int cmp_ptr_ptr (const void *, const void *); | |
1690a839 | 184 | |
c7e276b8 | 185 | /* Name to use in diagnostics. */ |
1690a839 DM |
186 | const char *m_name; |
187 | ||
c7e276b8 DM |
188 | /* Which wording to use in diagnostics. */ |
189 | enum wording m_wording; | |
190 | ||
191 | /* State for a value passed to one of the deallocators. */ | |
192 | state_machine::state_t m_freed; | |
193 | ||
194 | protected: | |
195 | deallocator (malloc_state_machine *sm, | |
196 | const char *name, | |
197 | enum wording wording); | |
198 | }; | |
199 | ||
200 | /* Subclass representing a predefined deallocator. | |
201 | e.g. "delete []", without needing a specific FUNCTION_DECL | |
202 | ahead of time. */ | |
203 | ||
204 | struct standard_deallocator : public deallocator | |
205 | { | |
206 | standard_deallocator (malloc_state_machine *sm, | |
207 | const char *name, | |
208 | enum wording wording); | |
209 | }; | |
210 | ||
211 | /* Subclass representing a user-defined deallocator | |
212 | via __attribute__((malloc(DEALLOCATOR))) given | |
213 | a specific FUNCTION_DECL. */ | |
214 | ||
215 | struct custom_deallocator : public deallocator | |
216 | { | |
217 | custom_deallocator (malloc_state_machine *sm, | |
218 | tree deallocator_fndecl, | |
219 | enum wording wording) | |
220 | : deallocator (sm, IDENTIFIER_POINTER (DECL_NAME (deallocator_fndecl)), | |
221 | wording) | |
222 | { | |
223 | } | |
224 | }; | |
225 | ||
226 | /* Base class representing a set of possible deallocators. | |
227 | Often this will be just a single deallocator, but some | |
228 | allocators have multiple valid deallocators (e.g. the result of | |
229 | "fopen" can be closed by either "fclose" or "freopen"). */ | |
230 | ||
231 | struct deallocator_set | |
232 | { | |
233 | deallocator_set (malloc_state_machine *sm, | |
234 | enum wording wording); | |
235 | virtual ~deallocator_set () {} | |
236 | ||
237 | virtual bool contains_p (const deallocator *d) const = 0; | |
238 | virtual const deallocator *maybe_get_single () const = 0; | |
239 | virtual void dump_to_pp (pretty_printer *pp) const = 0; | |
240 | void dump () const; | |
1690a839 DM |
241 | |
242 | /* Which wording to use in diagnostics. */ | |
243 | enum wording m_wording; | |
244 | ||
c7e276b8 | 245 | /* Pointers to states. |
1690a839 DM |
246 | These states are owned by the state_machine base class. */ |
247 | ||
c7e276b8 | 248 | /* State for an unchecked result from an allocator using this set. */ |
1690a839 DM |
249 | state_machine::state_t m_unchecked; |
250 | ||
c7e276b8 | 251 | /* State for a known non-NULL result from such an allocator. */ |
1690a839 | 252 | state_machine::state_t m_nonnull; |
c7e276b8 | 253 | }; |
1690a839 | 254 | |
c7e276b8 DM |
255 | /* Subclass of deallocator_set representing a set of deallocators |
256 | defined by one or more __attribute__((malloc(DEALLOCATOR))). */ | |
257 | ||
258 | struct custom_deallocator_set : public deallocator_set | |
259 | { | |
260 | typedef const auto_vec <const deallocator *> *key_t; | |
261 | ||
262 | custom_deallocator_set (malloc_state_machine *sm, | |
263 | const auto_vec <const deallocator *> *vec, | |
264 | //const char *name, | |
265 | //const char *dealloc_funcname, | |
266 | //unsigned arg_idx, | |
267 | enum wording wording); | |
268 | ||
ff171cb1 DM |
269 | bool contains_p (const deallocator *d) const final override; |
270 | const deallocator *maybe_get_single () const final override; | |
271 | void dump_to_pp (pretty_printer *pp) const final override; | |
c7e276b8 DM |
272 | |
273 | auto_vec <const deallocator *> m_deallocator_vec; | |
274 | }; | |
275 | ||
276 | /* Subclass of deallocator_set representing a set of deallocators | |
277 | with a single standard_deallocator, e.g. "delete []". */ | |
278 | ||
279 | struct standard_deallocator_set : public deallocator_set | |
280 | { | |
281 | standard_deallocator_set (malloc_state_machine *sm, | |
282 | const char *name, | |
283 | enum wording wording); | |
284 | ||
ff171cb1 DM |
285 | bool contains_p (const deallocator *d) const final override; |
286 | const deallocator *maybe_get_single () const final override; | |
287 | void dump_to_pp (pretty_printer *pp) const final override; | |
c7e276b8 DM |
288 | |
289 | standard_deallocator m_deallocator; | |
290 | }; | |
291 | ||
292 | /* Traits class for ensuring uniqueness of deallocator_sets within | |
293 | malloc_state_machine. */ | |
294 | ||
295 | struct deallocator_set_map_traits | |
296 | { | |
297 | typedef custom_deallocator_set::key_t key_type; | |
298 | typedef custom_deallocator_set *value_type; | |
299 | typedef custom_deallocator_set *compare_type; | |
300 | ||
301 | static inline hashval_t hash (const key_type &k) | |
302 | { | |
303 | gcc_assert (k != NULL); | |
304 | gcc_assert (k != reinterpret_cast<key_type> (1)); | |
305 | ||
306 | hashval_t result = 0; | |
307 | unsigned i; | |
308 | const deallocator *d; | |
309 | FOR_EACH_VEC_ELT (*k, i, d) | |
310 | result ^= d->hash (); | |
311 | return result; | |
312 | } | |
313 | static inline bool equal_keys (const key_type &k1, const key_type &k2) | |
314 | { | |
315 | if (k1->length () != k2->length ()) | |
316 | return false; | |
317 | ||
318 | for (unsigned i = 0; i < k1->length (); i++) | |
319 | if ((*k1)[i] != (*k2)[i]) | |
320 | return false; | |
321 | ||
322 | return true; | |
323 | } | |
324 | template <typename T> | |
325 | static inline void remove (T &) | |
326 | { | |
327 | /* empty; the nodes are handled elsewhere. */ | |
328 | } | |
329 | template <typename T> | |
330 | static inline void mark_deleted (T &entry) | |
331 | { | |
332 | entry.m_key = reinterpret_cast<key_type> (1); | |
333 | } | |
334 | template <typename T> | |
335 | static inline void mark_empty (T &entry) | |
336 | { | |
337 | entry.m_key = NULL; | |
338 | } | |
339 | template <typename T> | |
340 | static inline bool is_deleted (const T &entry) | |
341 | { | |
342 | return entry.m_key == reinterpret_cast<key_type> (1); | |
343 | } | |
344 | template <typename T> | |
345 | static inline bool is_empty (const T &entry) | |
346 | { | |
347 | return entry.m_key == NULL; | |
348 | } | |
349 | static const bool empty_zero_p = false; | |
1690a839 DM |
350 | }; |
351 | ||
757bf1df DM |
352 | /* A state machine for detecting misuses of the malloc/free API. |
353 | ||
354 | See sm-malloc.dot for an overview (keep this in-sync with that file). */ | |
355 | ||
356 | class malloc_state_machine : public state_machine | |
357 | { | |
358 | public: | |
1690a839 DM |
359 | typedef allocation_state custom_data_t; |
360 | ||
757bf1df | 361 | malloc_state_machine (logger *logger); |
c7e276b8 | 362 | ~malloc_state_machine (); |
757bf1df | 363 | |
1690a839 | 364 | state_t |
c7e276b8 DM |
365 | add_state (const char *name, enum resource_state rs, |
366 | const deallocator_set *deallocators, | |
367 | const deallocator *deallocator); | |
1690a839 | 368 | |
ff171cb1 | 369 | bool inherited_state_p () const final override { return false; } |
757bf1df | 370 | |
808f4dfe | 371 | state_machine::state_t |
ff171cb1 | 372 | get_default_state (const svalue *sval) const final override |
808f4dfe DM |
373 | { |
374 | if (tree cst = sval->maybe_get_constant ()) | |
375 | { | |
376 | if (zerop (cst)) | |
377 | return m_null; | |
378 | } | |
379 | if (const region_svalue *ptr = sval->dyn_cast_region_svalue ()) | |
380 | { | |
381 | const region *reg = ptr->get_pointee (); | |
a61aaee6 DM |
382 | switch (reg->get_memory_space ()) |
383 | { | |
384 | default: | |
385 | break; | |
386 | case MEMSPACE_CODE: | |
387 | case MEMSPACE_GLOBALS: | |
388 | case MEMSPACE_STACK: | |
389 | case MEMSPACE_READONLY_DATA: | |
390 | return m_non_heap; | |
391 | } | |
808f4dfe DM |
392 | } |
393 | return m_start; | |
394 | } | |
395 | ||
757bf1df DM |
396 | bool on_stmt (sm_context *sm_ctxt, |
397 | const supernode *node, | |
ff171cb1 | 398 | const gimple *stmt) const final override; |
757bf1df | 399 | |
8525d1f5 DM |
400 | void on_phi (sm_context *sm_ctxt, |
401 | const supernode *node, | |
402 | const gphi *phi, | |
ff171cb1 | 403 | tree rhs) const final override; |
8525d1f5 | 404 | |
757bf1df DM |
405 | void on_condition (sm_context *sm_ctxt, |
406 | const supernode *node, | |
407 | const gimple *stmt, | |
48e8a7a6 | 408 | const svalue *lhs, |
757bf1df | 409 | enum tree_code op, |
ff171cb1 | 410 | const svalue *rhs) const final override; |
757bf1df | 411 | |
5c6546ca DM |
412 | void on_pop_frame (sm_state_map *smap, |
413 | const frame_region *) const final override; | |
414 | ||
ff171cb1 | 415 | bool can_purge_p (state_t s) const final override; |
6341f14e | 416 | std::unique_ptr<pending_diagnostic> on_leak (tree var) const final override; |
757bf1df | 417 | |
808f4dfe | 418 | bool reset_when_passed_to_unknown_fn_p (state_t s, |
ff171cb1 | 419 | bool is_mutable) const final override; |
808f4dfe | 420 | |
5c6546ca DM |
421 | state_t |
422 | maybe_get_merged_states_nonequal (state_t state_a, | |
423 | state_t state_b) const final override; | |
424 | ||
cd323d97 DM |
425 | static bool unaffected_by_call_p (tree fndecl); |
426 | ||
5c6546ca DM |
427 | void maybe_assume_non_null (sm_context *sm_ctxt, |
428 | tree ptr, | |
429 | const gimple *stmt) const; | |
430 | ||
eafa9d96 DM |
431 | void on_realloc_with_move (region_model *model, |
432 | sm_state_map *smap, | |
433 | const svalue *old_ptr_sval, | |
434 | const svalue *new_ptr_sval, | |
435 | const extrinsic_state &ext_state) const; | |
436 | ||
c7e276b8 DM |
437 | standard_deallocator_set m_free; |
438 | standard_deallocator_set m_scalar_delete; | |
439 | standard_deallocator_set m_vector_delete; | |
1690a839 | 440 | |
a6baafca DM |
441 | standard_deallocator m_realloc; |
442 | ||
1690a839 | 443 | /* States that are independent of api. */ |
757bf1df | 444 | |
5c6546ca DM |
445 | /* States for a pointer that's been unconditionally dereferenced |
446 | in a particular stack frame. */ | |
447 | hash_map<const frame_region *, state_t> m_assumed_non_null; | |
448 | ||
757bf1df DM |
449 | /* State for a pointer that's known to be NULL. */ |
450 | state_t m_null; | |
451 | ||
757bf1df DM |
452 | /* State for a pointer that's known to not be on the heap (e.g. to a local |
453 | or global). */ | |
454 | state_t m_non_heap; // TODO: or should this be a different state machine? | |
455 | // or do we need child values etc? | |
456 | ||
457 | /* Stop state, for pointers we don't want to track any more. */ | |
458 | state_t m_stop; | |
8525d1f5 DM |
459 | |
460 | private: | |
c7e276b8 DM |
461 | const custom_deallocator_set * |
462 | get_or_create_custom_deallocator_set (tree allocator_fndecl); | |
463 | custom_deallocator_set * | |
464 | maybe_create_custom_deallocator_set (tree allocator_fndecl); | |
465 | const deallocator * | |
466 | get_or_create_deallocator (tree deallocator_fndecl); | |
467 | ||
5c6546ca DM |
468 | state_t |
469 | get_or_create_assumed_non_null_state_for_frame (const frame_region *frame); | |
470 | ||
471 | void | |
472 | maybe_complain_about_deref_before_check (sm_context *sm_ctxt, | |
473 | const supernode *node, | |
474 | const gimple *stmt, | |
475 | const assumed_non_null_state *, | |
476 | tree ptr) const; | |
477 | ||
1690a839 DM |
478 | void on_allocator_call (sm_context *sm_ctxt, |
479 | const gcall *call, | |
c7e276b8 DM |
480 | const deallocator_set *deallocators, |
481 | bool returns_nonnull = false) const; | |
a61aaee6 DM |
482 | void handle_free_of_non_heap (sm_context *sm_ctxt, |
483 | const supernode *node, | |
484 | const gcall *call, | |
485 | tree arg, | |
486 | const deallocator *d) const; | |
1690a839 DM |
487 | void on_deallocator_call (sm_context *sm_ctxt, |
488 | const supernode *node, | |
489 | const gcall *call, | |
c7e276b8 DM |
490 | const deallocator *d, |
491 | unsigned argno) const; | |
a6baafca DM |
492 | void on_realloc_call (sm_context *sm_ctxt, |
493 | const supernode *node, | |
494 | const gcall *call) const; | |
8525d1f5 | 495 | void on_zero_assignment (sm_context *sm_ctxt, |
8525d1f5 DM |
496 | const gimple *stmt, |
497 | tree lhs) const; | |
c7e276b8 DM |
498 | |
499 | /* A map for consolidating deallocators so that they are | |
500 | unique per deallocator FUNCTION_DECL. */ | |
501 | typedef hash_map<tree, deallocator *> deallocator_map_t; | |
502 | deallocator_map_t m_deallocator_map; | |
503 | ||
504 | /* Memoized lookups from FUNCTION_DECL to custom_deallocator_set *. */ | |
505 | typedef hash_map<tree, custom_deallocator_set *> deallocator_set_cache_t; | |
506 | deallocator_set_cache_t m_custom_deallocator_set_cache; | |
507 | ||
508 | /* A map for consolidating custom_deallocator_set instances. */ | |
509 | typedef hash_map<custom_deallocator_set::key_t, | |
510 | custom_deallocator_set *, | |
511 | deallocator_set_map_traits> custom_deallocator_set_map_t; | |
512 | custom_deallocator_set_map_t m_custom_deallocator_set_map; | |
513 | ||
514 | /* Record of dynamically-allocated objects, for cleanup. */ | |
515 | auto_vec <custom_deallocator_set *> m_dynamic_sets; | |
516 | auto_vec <custom_deallocator *> m_dynamic_deallocators; | |
757bf1df DM |
517 | }; |
518 | ||
c7e276b8 | 519 | /* struct deallocator. */ |
1690a839 | 520 | |
c7e276b8 DM |
521 | deallocator::deallocator (malloc_state_machine *sm, |
522 | const char *name, | |
523 | enum wording wording) | |
1690a839 | 524 | : m_name (name), |
1690a839 | 525 | m_wording (wording), |
c7e276b8 DM |
526 | m_freed (sm->add_state ("freed", RS_FREED, NULL, this)) |
527 | { | |
528 | } | |
529 | ||
530 | hashval_t | |
531 | deallocator::hash () const | |
532 | { | |
533 | return (hashval_t)m_freed->get_id (); | |
534 | } | |
535 | ||
536 | void | |
537 | deallocator::dump_to_pp (pretty_printer *pp) const | |
538 | { | |
539 | pp_printf (pp, "%qs", m_name); | |
540 | } | |
541 | ||
542 | int | |
543 | deallocator::cmp (const deallocator *a, const deallocator *b) | |
544 | { | |
545 | return (int)a->m_freed->get_id () - (int)b->m_freed->get_id (); | |
546 | } | |
547 | ||
548 | int | |
549 | deallocator::cmp_ptr_ptr (const void *a, const void *b) | |
550 | { | |
551 | return cmp (*(const deallocator * const *)a, | |
552 | *(const deallocator * const *)b); | |
553 | } | |
554 | ||
555 | ||
556 | /* struct standard_deallocator : public deallocator. */ | |
557 | ||
558 | standard_deallocator::standard_deallocator (malloc_state_machine *sm, | |
559 | const char *name, | |
560 | enum wording wording) | |
561 | : deallocator (sm, name, wording) | |
1690a839 DM |
562 | { |
563 | } | |
564 | ||
c7e276b8 DM |
565 | /* struct deallocator_set. */ |
566 | ||
567 | deallocator_set::deallocator_set (malloc_state_machine *sm, | |
568 | enum wording wording) | |
569 | : m_wording (wording), | |
570 | m_unchecked (sm->add_state ("unchecked", RS_UNCHECKED, this, NULL)), | |
571 | m_nonnull (sm->add_state ("nonnull", RS_NONNULL, this, NULL)) | |
572 | { | |
573 | } | |
574 | ||
575 | /* Dump a description of this deallocator_set to stderr. */ | |
576 | ||
577 | DEBUG_FUNCTION void | |
578 | deallocator_set::dump () const | |
579 | { | |
580 | pretty_printer pp; | |
581 | pp_show_color (&pp) = pp_show_color (global_dc->printer); | |
582 | pp.buffer->stream = stderr; | |
583 | dump_to_pp (&pp); | |
584 | pp_newline (&pp); | |
585 | pp_flush (&pp); | |
586 | } | |
587 | ||
588 | /* struct custom_deallocator_set : public deallocator_set. */ | |
589 | ||
590 | custom_deallocator_set:: | |
591 | custom_deallocator_set (malloc_state_machine *sm, | |
592 | const auto_vec <const deallocator *> *vec, | |
593 | enum wording wording) | |
594 | : deallocator_set (sm, wording), | |
595 | m_deallocator_vec (vec->length ()) | |
596 | { | |
597 | unsigned i; | |
598 | const deallocator *d; | |
599 | FOR_EACH_VEC_ELT (*vec, i, d) | |
600 | m_deallocator_vec.safe_push (d); | |
601 | } | |
602 | ||
603 | bool | |
604 | custom_deallocator_set::contains_p (const deallocator *d) const | |
605 | { | |
606 | unsigned i; | |
607 | const deallocator *cd; | |
608 | FOR_EACH_VEC_ELT (m_deallocator_vec, i, cd) | |
609 | if (cd == d) | |
610 | return true; | |
611 | return false; | |
612 | } | |
613 | ||
614 | const deallocator * | |
615 | custom_deallocator_set::maybe_get_single () const | |
616 | { | |
617 | if (m_deallocator_vec.length () == 1) | |
618 | return m_deallocator_vec[0]; | |
619 | return NULL; | |
620 | } | |
621 | ||
622 | void | |
623 | custom_deallocator_set::dump_to_pp (pretty_printer *pp) const | |
624 | { | |
625 | pp_character (pp, '{'); | |
626 | unsigned i; | |
627 | const deallocator *d; | |
628 | FOR_EACH_VEC_ELT (m_deallocator_vec, i, d) | |
629 | { | |
630 | if (i > 0) | |
631 | pp_string (pp, ", "); | |
632 | d->dump_to_pp (pp); | |
633 | } | |
634 | pp_character (pp, '}'); | |
635 | } | |
636 | ||
637 | /* struct standard_deallocator_set : public deallocator_set. */ | |
638 | ||
639 | standard_deallocator_set::standard_deallocator_set (malloc_state_machine *sm, | |
640 | const char *name, | |
641 | enum wording wording) | |
642 | : deallocator_set (sm, wording), | |
643 | m_deallocator (sm, name, wording) | |
644 | { | |
645 | } | |
646 | ||
647 | bool | |
648 | standard_deallocator_set::contains_p (const deallocator *d) const | |
649 | { | |
650 | return d == &m_deallocator; | |
651 | } | |
652 | ||
653 | const deallocator * | |
654 | standard_deallocator_set::maybe_get_single () const | |
655 | { | |
656 | return &m_deallocator; | |
657 | } | |
658 | ||
659 | void | |
660 | standard_deallocator_set::dump_to_pp (pretty_printer *pp) const | |
661 | { | |
662 | pp_character (pp, '{'); | |
663 | pp_string (pp, m_deallocator.m_name); | |
664 | pp_character (pp, '}'); | |
665 | } | |
666 | ||
1690a839 DM |
667 | /* Return STATE cast to the custom state subclass, or NULL for the start state. |
668 | Everything should be an allocation_state apart from the start state. */ | |
669 | ||
670 | static const allocation_state * | |
671 | dyn_cast_allocation_state (state_machine::state_t state) | |
672 | { | |
673 | if (state->get_id () == 0) | |
674 | return NULL; | |
675 | return static_cast <const allocation_state *> (state); | |
676 | } | |
677 | ||
678 | /* Return STATE cast to the custom state subclass, for a state that is | |
679 | already known to not be the start state . */ | |
680 | ||
681 | static const allocation_state * | |
682 | as_a_allocation_state (state_machine::state_t state) | |
683 | { | |
684 | gcc_assert (state->get_id () != 0); | |
685 | return static_cast <const allocation_state *> (state); | |
686 | } | |
687 | ||
688 | /* Get the resource_state for STATE. */ | |
689 | ||
690 | static enum resource_state | |
691 | get_rs (state_machine::state_t state) | |
692 | { | |
693 | if (const allocation_state *astate = dyn_cast_allocation_state (state)) | |
694 | return astate->m_rs; | |
695 | else | |
696 | return RS_START; | |
697 | } | |
698 | ||
c7e276b8 DM |
699 | /* Return true if STATE is the start state. */ |
700 | ||
701 | static bool | |
702 | start_p (state_machine::state_t state) | |
703 | { | |
704 | return get_rs (state) == RS_START; | |
705 | } | |
706 | ||
1690a839 DM |
707 | /* Return true if STATE is an unchecked result from an allocator. */ |
708 | ||
709 | static bool | |
710 | unchecked_p (state_machine::state_t state) | |
711 | { | |
712 | return get_rs (state) == RS_UNCHECKED; | |
713 | } | |
714 | ||
715 | /* Return true if STATE is a non-null result from an allocator. */ | |
716 | ||
717 | static bool | |
718 | nonnull_p (state_machine::state_t state) | |
719 | { | |
720 | return get_rs (state) == RS_NONNULL; | |
721 | } | |
722 | ||
723 | /* Return true if STATE is a value that has been passed to a deallocator. */ | |
724 | ||
725 | static bool | |
726 | freed_p (state_machine::state_t state) | |
727 | { | |
728 | return get_rs (state) == RS_FREED; | |
729 | } | |
730 | ||
5c6546ca DM |
731 | /* Return true if STATE is a value that has been assumed to be non-NULL. */ |
732 | ||
733 | static bool | |
734 | assumed_non_null_p (state_machine::state_t state) | |
735 | { | |
736 | return get_rs (state) == RS_ASSUMED_NON_NULL; | |
737 | } | |
738 | ||
757bf1df DM |
739 | /* Class for diagnostics relating to malloc_state_machine. */ |
740 | ||
741 | class malloc_diagnostic : public pending_diagnostic | |
742 | { | |
743 | public: | |
744 | malloc_diagnostic (const malloc_state_machine &sm, tree arg) | |
745 | : m_sm (sm), m_arg (arg) | |
746 | {} | |
747 | ||
ff171cb1 | 748 | bool subclass_equal_p (const pending_diagnostic &base_other) const override |
757bf1df | 749 | { |
14f9d7b9 | 750 | return same_tree_p (m_arg, ((const malloc_diagnostic &)base_other).m_arg); |
757bf1df DM |
751 | } |
752 | ||
753 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 754 | override |
757bf1df | 755 | { |
10fc42a8 | 756 | if (change.m_old_state == m_sm.get_start_state () |
1690a839 | 757 | && unchecked_p (change.m_new_state)) |
757bf1df DM |
758 | // TODO: verify that it's the allocation stmt, not a copy |
759 | return label_text::borrow ("allocated here"); | |
1690a839 DM |
760 | if (unchecked_p (change.m_old_state) |
761 | && nonnull_p (change.m_new_state)) | |
808f4dfe DM |
762 | { |
763 | if (change.m_expr) | |
764 | return change.formatted_print ("assuming %qE is non-NULL", | |
765 | change.m_expr); | |
766 | else | |
767 | return change.formatted_print ("assuming %qs is non-NULL", | |
768 | "<unknown>"); | |
769 | } | |
757bf1df | 770 | if (change.m_new_state == m_sm.m_null) |
0993ad65 | 771 | { |
1690a839 | 772 | if (unchecked_p (change.m_old_state)) |
808f4dfe DM |
773 | { |
774 | if (change.m_expr) | |
775 | return change.formatted_print ("assuming %qE is NULL", | |
776 | change.m_expr); | |
777 | else | |
778 | return change.formatted_print ("assuming %qs is NULL", | |
779 | "<unknown>"); | |
780 | } | |
0993ad65 | 781 | else |
808f4dfe DM |
782 | { |
783 | if (change.m_expr) | |
784 | return change.formatted_print ("%qE is NULL", | |
785 | change.m_expr); | |
786 | else | |
787 | return change.formatted_print ("%qs is NULL", | |
788 | "<unknown>"); | |
789 | } | |
0993ad65 DM |
790 | } |
791 | ||
757bf1df DM |
792 | return label_text (); |
793 | } | |
794 | ||
6cf276dd DM |
795 | diagnostic_event::meaning |
796 | get_meaning_for_state_change (const evdesc::state_change &change) | |
797 | const final override | |
798 | { | |
799 | if (change.m_old_state == m_sm.get_start_state () | |
800 | && unchecked_p (change.m_new_state)) | |
801 | return diagnostic_event::meaning (diagnostic_event::VERB_acquire, | |
802 | diagnostic_event::NOUN_memory); | |
803 | if (freed_p (change.m_new_state)) | |
804 | return diagnostic_event::meaning (diagnostic_event::VERB_release, | |
805 | diagnostic_event::NOUN_memory); | |
806 | return diagnostic_event::meaning (); | |
807 | } | |
808 | ||
757bf1df DM |
809 | protected: |
810 | const malloc_state_machine &m_sm; | |
811 | tree m_arg; | |
812 | }; | |
813 | ||
1690a839 DM |
814 | /* Concrete subclass for reporting mismatching allocator/deallocator |
815 | diagnostics. */ | |
816 | ||
817 | class mismatching_deallocation : public malloc_diagnostic | |
818 | { | |
819 | public: | |
820 | mismatching_deallocation (const malloc_state_machine &sm, tree arg, | |
c7e276b8 DM |
821 | const deallocator_set *expected_deallocators, |
822 | const deallocator *actual_dealloc) | |
1690a839 | 823 | : malloc_diagnostic (sm, arg), |
c7e276b8 | 824 | m_expected_deallocators (expected_deallocators), |
1690a839 DM |
825 | m_actual_dealloc (actual_dealloc) |
826 | {} | |
827 | ||
ff171cb1 | 828 | const char *get_kind () const final override |
1690a839 DM |
829 | { |
830 | return "mismatching_deallocation"; | |
831 | } | |
832 | ||
ff171cb1 | 833 | int get_controlling_option () const final override |
7fd6e36e DM |
834 | { |
835 | return OPT_Wanalyzer_mismatching_deallocation; | |
836 | } | |
837 | ||
ff171cb1 | 838 | bool emit (rich_location *rich_loc) final override |
1690a839 DM |
839 | { |
840 | auto_diagnostic_group d; | |
841 | diagnostic_metadata m; | |
842 | m.add_cwe (762); /* CWE-762: Mismatched Memory Management Routines. */ | |
c7e276b8 DM |
843 | if (const deallocator *expected_dealloc |
844 | = m_expected_deallocators->maybe_get_single ()) | |
7fd6e36e | 845 | return warning_meta (rich_loc, m, get_controlling_option (), |
c7e276b8 DM |
846 | "%qE should have been deallocated with %qs" |
847 | " but was deallocated with %qs", | |
848 | m_arg, expected_dealloc->m_name, | |
849 | m_actual_dealloc->m_name); | |
850 | else | |
7fd6e36e | 851 | return warning_meta (rich_loc, m, get_controlling_option (), |
c7e276b8 DM |
852 | "%qs called on %qE returned from a mismatched" |
853 | " allocation function", | |
854 | m_actual_dealloc->m_name, m_arg); | |
1690a839 DM |
855 | } |
856 | ||
857 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 858 | final override |
1690a839 DM |
859 | { |
860 | if (unchecked_p (change.m_new_state)) | |
861 | { | |
862 | m_alloc_event = change.m_event_id; | |
c7e276b8 DM |
863 | if (const deallocator *expected_dealloc |
864 | = m_expected_deallocators->maybe_get_single ()) | |
865 | return change.formatted_print ("allocated here" | |
866 | " (expects deallocation with %qs)", | |
867 | expected_dealloc->m_name); | |
868 | else | |
869 | return change.formatted_print ("allocated here"); | |
1690a839 DM |
870 | } |
871 | return malloc_diagnostic::describe_state_change (change); | |
872 | } | |
873 | ||
ff171cb1 | 874 | label_text describe_final_event (const evdesc::final_event &ev) final override |
1690a839 DM |
875 | { |
876 | if (m_alloc_event.known_p ()) | |
c7e276b8 DM |
877 | { |
878 | if (const deallocator *expected_dealloc | |
879 | = m_expected_deallocators->maybe_get_single ()) | |
880 | return ev.formatted_print | |
881 | ("deallocated with %qs here;" | |
882 | " allocation at %@ expects deallocation with %qs", | |
883 | m_actual_dealloc->m_name, &m_alloc_event, | |
884 | expected_dealloc->m_name); | |
885 | else | |
886 | return ev.formatted_print | |
887 | ("deallocated with %qs here;" | |
888 | " allocated at %@", | |
889 | m_actual_dealloc->m_name, &m_alloc_event); | |
890 | } | |
1690a839 | 891 | return ev.formatted_print ("deallocated with %qs here", |
c7e276b8 | 892 | m_actual_dealloc->m_name); |
1690a839 DM |
893 | } |
894 | ||
895 | private: | |
896 | diagnostic_event_id_t m_alloc_event; | |
c7e276b8 DM |
897 | const deallocator_set *m_expected_deallocators; |
898 | const deallocator *m_actual_dealloc; | |
1690a839 DM |
899 | }; |
900 | ||
757bf1df DM |
901 | /* Concrete subclass for reporting double-free diagnostics. */ |
902 | ||
903 | class double_free : public malloc_diagnostic | |
904 | { | |
905 | public: | |
1690a839 DM |
906 | double_free (const malloc_state_machine &sm, tree arg, const char *funcname) |
907 | : malloc_diagnostic (sm, arg), m_funcname (funcname) | |
757bf1df DM |
908 | {} |
909 | ||
ff171cb1 | 910 | const char *get_kind () const final override { return "double_free"; } |
757bf1df | 911 | |
ff171cb1 | 912 | int get_controlling_option () const final override |
7fd6e36e DM |
913 | { |
914 | return OPT_Wanalyzer_double_free; | |
915 | } | |
916 | ||
ff171cb1 | 917 | bool emit (rich_location *rich_loc) final override |
757bf1df DM |
918 | { |
919 | auto_diagnostic_group d; | |
920 | diagnostic_metadata m; | |
921 | m.add_cwe (415); /* CWE-415: Double Free. */ | |
7fd6e36e | 922 | return warning_meta (rich_loc, m, get_controlling_option (), |
c7e276b8 | 923 | "double-%qs of %qE", m_funcname, m_arg); |
757bf1df DM |
924 | } |
925 | ||
926 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 927 | final override |
757bf1df | 928 | { |
1690a839 | 929 | if (freed_p (change.m_new_state)) |
757bf1df DM |
930 | { |
931 | m_first_free_event = change.m_event_id; | |
1690a839 | 932 | return change.formatted_print ("first %qs here", m_funcname); |
757bf1df DM |
933 | } |
934 | return malloc_diagnostic::describe_state_change (change); | |
935 | } | |
936 | ||
937 | label_text describe_call_with_state (const evdesc::call_with_state &info) | |
ff171cb1 | 938 | final override |
757bf1df | 939 | { |
1690a839 | 940 | if (freed_p (info.m_state)) |
757bf1df DM |
941 | return info.formatted_print |
942 | ("passing freed pointer %qE in call to %qE from %qE", | |
943 | info.m_expr, info.m_callee_fndecl, info.m_caller_fndecl); | |
944 | return label_text (); | |
945 | } | |
946 | ||
ff171cb1 | 947 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df DM |
948 | { |
949 | if (m_first_free_event.known_p ()) | |
950 | return ev.formatted_print ("second %qs here; first %qs was at %@", | |
1690a839 | 951 | m_funcname, m_funcname, |
757bf1df | 952 | &m_first_free_event); |
1690a839 | 953 | return ev.formatted_print ("second %qs here", m_funcname); |
757bf1df DM |
954 | } |
955 | ||
956 | private: | |
957 | diagnostic_event_id_t m_first_free_event; | |
1690a839 | 958 | const char *m_funcname; |
757bf1df DM |
959 | }; |
960 | ||
961 | /* Abstract subclass for describing possible bad uses of NULL. | |
962 | Responsible for describing the call that could return NULL. */ | |
963 | ||
964 | class possible_null : public malloc_diagnostic | |
965 | { | |
966 | public: | |
967 | possible_null (const malloc_state_machine &sm, tree arg) | |
968 | : malloc_diagnostic (sm, arg) | |
969 | {} | |
970 | ||
971 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 972 | final override |
757bf1df | 973 | { |
10fc42a8 | 974 | if (change.m_old_state == m_sm.get_start_state () |
1690a839 | 975 | && unchecked_p (change.m_new_state)) |
757bf1df DM |
976 | { |
977 | m_origin_of_unchecked_event = change.m_event_id; | |
978 | return label_text::borrow ("this call could return NULL"); | |
979 | } | |
980 | return malloc_diagnostic::describe_state_change (change); | |
981 | } | |
982 | ||
983 | label_text describe_return_of_state (const evdesc::return_of_state &info) | |
ff171cb1 | 984 | final override |
757bf1df | 985 | { |
1690a839 | 986 | if (unchecked_p (info.m_state)) |
757bf1df DM |
987 | return info.formatted_print ("possible return of NULL to %qE from %qE", |
988 | info.m_caller_fndecl, info.m_callee_fndecl); | |
989 | return label_text (); | |
990 | } | |
991 | ||
992 | protected: | |
993 | diagnostic_event_id_t m_origin_of_unchecked_event; | |
994 | }; | |
995 | ||
996 | /* Concrete subclass for describing dereference of a possible NULL | |
997 | value. */ | |
998 | ||
999 | class possible_null_deref : public possible_null | |
1000 | { | |
1001 | public: | |
1002 | possible_null_deref (const malloc_state_machine &sm, tree arg) | |
1003 | : possible_null (sm, arg) | |
1004 | {} | |
1005 | ||
ff171cb1 | 1006 | const char *get_kind () const final override { return "possible_null_deref"; } |
757bf1df | 1007 | |
ff171cb1 | 1008 | int get_controlling_option () const final override |
7fd6e36e DM |
1009 | { |
1010 | return OPT_Wanalyzer_possible_null_dereference; | |
1011 | } | |
1012 | ||
ff171cb1 | 1013 | bool emit (rich_location *rich_loc) final override |
757bf1df DM |
1014 | { |
1015 | /* CWE-690: Unchecked Return Value to NULL Pointer Dereference. */ | |
1016 | diagnostic_metadata m; | |
1017 | m.add_cwe (690); | |
7fd6e36e | 1018 | return warning_meta (rich_loc, m, get_controlling_option (), |
6c8e5844 | 1019 | "dereference of possibly-NULL %qE", m_arg); |
757bf1df DM |
1020 | } |
1021 | ||
ff171cb1 | 1022 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df DM |
1023 | { |
1024 | if (m_origin_of_unchecked_event.known_p ()) | |
1025 | return ev.formatted_print ("%qE could be NULL: unchecked value from %@", | |
1026 | ev.m_expr, | |
1027 | &m_origin_of_unchecked_event); | |
1028 | else | |
1029 | return ev.formatted_print ("%qE could be NULL", ev.m_expr); | |
1030 | } | |
1031 | ||
1032 | }; | |
1033 | ||
2f7c50b7 DM |
1034 | /* Return true if FNDECL is a C++ method. */ |
1035 | ||
1036 | static bool | |
1037 | method_p (tree fndecl) | |
1038 | { | |
1039 | return TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE; | |
1040 | } | |
1041 | ||
1042 | /* Return a 1-based description of ARG_IDX (0-based) of FNDECL. | |
e53b6e56 | 1043 | Compare with %P in the C++ FE (implemented in cp/error.cc: parm_to_string |
2f7c50b7 DM |
1044 | as called from cp_printer). */ |
1045 | ||
1046 | static label_text | |
1047 | describe_argument_index (tree fndecl, int arg_idx) | |
1048 | { | |
1049 | if (method_p (fndecl)) | |
1050 | if (arg_idx == 0) | |
1051 | return label_text::borrow ("'this'"); | |
1052 | pretty_printer pp; | |
1053 | pp_printf (&pp, "%u", arg_idx + 1 - method_p (fndecl)); | |
1054 | return label_text::take (xstrdup (pp_formatted_text (&pp))); | |
1055 | } | |
1056 | ||
757bf1df DM |
1057 | /* Subroutine for use by possible_null_arg::emit and null_arg::emit. |
1058 | Issue a note informing that the pertinent argument must be non-NULL. */ | |
1059 | ||
1060 | static void | |
1061 | inform_nonnull_attribute (tree fndecl, int arg_idx) | |
1062 | { | |
2f7c50b7 | 1063 | label_text arg_desc = describe_argument_index (fndecl, arg_idx); |
757bf1df | 1064 | inform (DECL_SOURCE_LOCATION (fndecl), |
2f7c50b7 | 1065 | "argument %s of %qD must be non-null", |
f858fe7a | 1066 | arg_desc.get (), fndecl); |
757bf1df DM |
1067 | /* Ideally we would use the location of the parm and underline the |
1068 | attribute also - but we don't have the location_t values at this point | |
1069 | in the middle-end. | |
1070 | For reference, the C and C++ FEs have get_fndecl_argument_location. */ | |
1071 | } | |
1072 | ||
1073 | /* Concrete subclass for describing passing a possibly-NULL value to a | |
1074 | function marked with __attribute__((nonnull)). */ | |
1075 | ||
1076 | class possible_null_arg : public possible_null | |
1077 | { | |
1078 | public: | |
1079 | possible_null_arg (const malloc_state_machine &sm, tree arg, | |
1080 | tree fndecl, int arg_idx) | |
1081 | : possible_null (sm, arg), | |
1082 | m_fndecl (fndecl), m_arg_idx (arg_idx) | |
1083 | {} | |
1084 | ||
ff171cb1 | 1085 | const char *get_kind () const final override { return "possible_null_arg"; } |
757bf1df | 1086 | |
2ac1459f DM |
1087 | bool subclass_equal_p (const pending_diagnostic &base_other) |
1088 | const final override | |
757bf1df DM |
1089 | { |
1090 | const possible_null_arg &sub_other | |
1091 | = (const possible_null_arg &)base_other; | |
14f9d7b9 | 1092 | return (same_tree_p (m_arg, sub_other.m_arg) |
757bf1df DM |
1093 | && m_fndecl == sub_other.m_fndecl |
1094 | && m_arg_idx == sub_other.m_arg_idx); | |
1095 | } | |
1096 | ||
ff171cb1 | 1097 | int get_controlling_option () const final override |
7fd6e36e DM |
1098 | { |
1099 | return OPT_Wanalyzer_possible_null_argument; | |
1100 | } | |
757bf1df | 1101 | |
ff171cb1 | 1102 | bool emit (rich_location *rich_loc) final override |
757bf1df DM |
1103 | { |
1104 | /* CWE-690: Unchecked Return Value to NULL Pointer Dereference. */ | |
1105 | auto_diagnostic_group d; | |
1106 | diagnostic_metadata m; | |
1107 | m.add_cwe (690); | |
1108 | bool warned | |
7fd6e36e | 1109 | = warning_meta (rich_loc, m, get_controlling_option (), |
6c8e5844 DM |
1110 | "use of possibly-NULL %qE where non-null expected", |
1111 | m_arg); | |
757bf1df DM |
1112 | if (warned) |
1113 | inform_nonnull_attribute (m_fndecl, m_arg_idx); | |
1114 | return warned; | |
1115 | } | |
1116 | ||
ff171cb1 | 1117 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df | 1118 | { |
2f7c50b7 DM |
1119 | label_text arg_desc = describe_argument_index (m_fndecl, m_arg_idx); |
1120 | label_text result; | |
757bf1df | 1121 | if (m_origin_of_unchecked_event.known_p ()) |
2f7c50b7 DM |
1122 | result = ev.formatted_print ("argument %s (%qE) from %@ could be NULL" |
1123 | " where non-null expected", | |
f858fe7a | 1124 | arg_desc.get (), ev.m_expr, |
2f7c50b7 | 1125 | &m_origin_of_unchecked_event); |
757bf1df | 1126 | else |
2f7c50b7 DM |
1127 | result = ev.formatted_print ("argument %s (%qE) could be NULL" |
1128 | " where non-null expected", | |
f858fe7a | 1129 | arg_desc.get (), ev.m_expr); |
2f7c50b7 | 1130 | return result; |
757bf1df DM |
1131 | } |
1132 | ||
1133 | private: | |
1134 | tree m_fndecl; | |
1135 | int m_arg_idx; | |
1136 | }; | |
1137 | ||
1138 | /* Concrete subclass for describing a dereference of a NULL value. */ | |
1139 | ||
1140 | class null_deref : public malloc_diagnostic | |
1141 | { | |
1142 | public: | |
1143 | null_deref (const malloc_state_machine &sm, tree arg) | |
1144 | : malloc_diagnostic (sm, arg) {} | |
1145 | ||
ff171cb1 | 1146 | const char *get_kind () const final override { return "null_deref"; } |
757bf1df | 1147 | |
ff171cb1 | 1148 | int get_controlling_option () const final override |
7fd6e36e DM |
1149 | { |
1150 | return OPT_Wanalyzer_null_dereference; | |
1151 | } | |
1152 | ||
ff171cb1 | 1153 | bool emit (rich_location *rich_loc) final override |
757bf1df | 1154 | { |
f3f312b5 | 1155 | /* CWE-476: NULL Pointer Dereference. */ |
757bf1df | 1156 | diagnostic_metadata m; |
f3f312b5 | 1157 | m.add_cwe (476); |
7fd6e36e | 1158 | return warning_meta (rich_loc, m, get_controlling_option (), |
6c8e5844 | 1159 | "dereference of NULL %qE", m_arg); |
757bf1df DM |
1160 | } |
1161 | ||
1162 | label_text describe_return_of_state (const evdesc::return_of_state &info) | |
ff171cb1 | 1163 | final override |
757bf1df DM |
1164 | { |
1165 | if (info.m_state == m_sm.m_null) | |
1166 | return info.formatted_print ("return of NULL to %qE from %qE", | |
1167 | info.m_caller_fndecl, info.m_callee_fndecl); | |
1168 | return label_text (); | |
1169 | } | |
1170 | ||
ff171cb1 | 1171 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df DM |
1172 | { |
1173 | return ev.formatted_print ("dereference of NULL %qE", ev.m_expr); | |
1174 | } | |
1175 | }; | |
1176 | ||
1177 | /* Concrete subclass for describing passing a NULL value to a | |
1178 | function marked with __attribute__((nonnull)). */ | |
1179 | ||
1180 | class null_arg : public malloc_diagnostic | |
1181 | { | |
1182 | public: | |
1183 | null_arg (const malloc_state_machine &sm, tree arg, | |
1184 | tree fndecl, int arg_idx) | |
1185 | : malloc_diagnostic (sm, arg), | |
1186 | m_fndecl (fndecl), m_arg_idx (arg_idx) | |
1187 | {} | |
1188 | ||
ff171cb1 | 1189 | const char *get_kind () const final override { return "null_arg"; } |
757bf1df | 1190 | |
2ac1459f DM |
1191 | bool subclass_equal_p (const pending_diagnostic &base_other) |
1192 | const final override | |
757bf1df DM |
1193 | { |
1194 | const null_arg &sub_other | |
1195 | = (const null_arg &)base_other; | |
14f9d7b9 | 1196 | return (same_tree_p (m_arg, sub_other.m_arg) |
757bf1df DM |
1197 | && m_fndecl == sub_other.m_fndecl |
1198 | && m_arg_idx == sub_other.m_arg_idx); | |
1199 | } | |
1200 | ||
ff171cb1 | 1201 | int get_controlling_option () const final override |
7fd6e36e DM |
1202 | { |
1203 | return OPT_Wanalyzer_null_argument; | |
1204 | } | |
1205 | ||
ff171cb1 | 1206 | bool emit (rich_location *rich_loc) final override |
757bf1df | 1207 | { |
f3f312b5 | 1208 | /* CWE-476: NULL Pointer Dereference. */ |
757bf1df DM |
1209 | auto_diagnostic_group d; |
1210 | diagnostic_metadata m; | |
f3f312b5 | 1211 | m.add_cwe (476); |
808f4dfe DM |
1212 | |
1213 | bool warned; | |
1214 | if (zerop (m_arg)) | |
7fd6e36e | 1215 | warned = warning_meta (rich_loc, m, get_controlling_option (), |
808f4dfe DM |
1216 | "use of NULL where non-null expected"); |
1217 | else | |
7fd6e36e | 1218 | warned = warning_meta (rich_loc, m, get_controlling_option (), |
808f4dfe DM |
1219 | "use of NULL %qE where non-null expected", |
1220 | m_arg); | |
757bf1df DM |
1221 | if (warned) |
1222 | inform_nonnull_attribute (m_fndecl, m_arg_idx); | |
1223 | return warned; | |
1224 | } | |
1225 | ||
ff171cb1 | 1226 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df | 1227 | { |
2f7c50b7 DM |
1228 | label_text arg_desc = describe_argument_index (m_fndecl, m_arg_idx); |
1229 | label_text result; | |
808f4dfe | 1230 | if (zerop (ev.m_expr)) |
2f7c50b7 | 1231 | result = ev.formatted_print ("argument %s NULL where non-null expected", |
f858fe7a | 1232 | arg_desc.get ()); |
808f4dfe | 1233 | else |
2f7c50b7 DM |
1234 | result = ev.formatted_print ("argument %s (%qE) NULL" |
1235 | " where non-null expected", | |
f858fe7a | 1236 | arg_desc.get (), ev.m_expr); |
2f7c50b7 | 1237 | return result; |
757bf1df DM |
1238 | } |
1239 | ||
1240 | private: | |
1241 | tree m_fndecl; | |
1242 | int m_arg_idx; | |
1243 | }; | |
1244 | ||
1245 | class use_after_free : public malloc_diagnostic | |
1246 | { | |
1247 | public: | |
1690a839 | 1248 | use_after_free (const malloc_state_machine &sm, tree arg, |
c7e276b8 DM |
1249 | const deallocator *deallocator) |
1250 | : malloc_diagnostic (sm, arg), | |
1251 | m_deallocator (deallocator) | |
1252 | { | |
1253 | gcc_assert (deallocator); | |
1254 | } | |
757bf1df | 1255 | |
ff171cb1 | 1256 | const char *get_kind () const final override { return "use_after_free"; } |
757bf1df | 1257 | |
ff171cb1 | 1258 | int get_controlling_option () const final override |
7fd6e36e DM |
1259 | { |
1260 | return OPT_Wanalyzer_use_after_free; | |
1261 | } | |
1262 | ||
ff171cb1 | 1263 | bool emit (rich_location *rich_loc) final override |
757bf1df DM |
1264 | { |
1265 | /* CWE-416: Use After Free. */ | |
1266 | diagnostic_metadata m; | |
1267 | m.add_cwe (416); | |
7fd6e36e | 1268 | return warning_meta (rich_loc, m, get_controlling_option (), |
1690a839 | 1269 | "use after %<%s%> of %qE", |
c7e276b8 | 1270 | m_deallocator->m_name, m_arg); |
757bf1df DM |
1271 | } |
1272 | ||
1273 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 1274 | final override |
757bf1df | 1275 | { |
1690a839 | 1276 | if (freed_p (change.m_new_state)) |
757bf1df DM |
1277 | { |
1278 | m_free_event = change.m_event_id; | |
c7e276b8 | 1279 | switch (m_deallocator->m_wording) |
1690a839 DM |
1280 | { |
1281 | default: | |
a6baafca | 1282 | case WORDING_REALLOCATED: |
1690a839 DM |
1283 | gcc_unreachable (); |
1284 | case WORDING_FREED: | |
1285 | return label_text::borrow ("freed here"); | |
1286 | case WORDING_DELETED: | |
1287 | return label_text::borrow ("deleted here"); | |
c7e276b8 DM |
1288 | case WORDING_DEALLOCATED: |
1289 | return label_text::borrow ("deallocated here"); | |
1690a839 | 1290 | } |
757bf1df DM |
1291 | } |
1292 | return malloc_diagnostic::describe_state_change (change); | |
1293 | } | |
1294 | ||
ff171cb1 | 1295 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df | 1296 | { |
c7e276b8 | 1297 | const char *funcname = m_deallocator->m_name; |
757bf1df | 1298 | if (m_free_event.known_p ()) |
c7e276b8 | 1299 | switch (m_deallocator->m_wording) |
1690a839 DM |
1300 | { |
1301 | default: | |
a6baafca | 1302 | case WORDING_REALLOCATED: |
1690a839 DM |
1303 | gcc_unreachable (); |
1304 | case WORDING_FREED: | |
1305 | return ev.formatted_print ("use after %<%s%> of %qE; freed at %@", | |
1306 | funcname, ev.m_expr, &m_free_event); | |
1307 | case WORDING_DELETED: | |
1308 | return ev.formatted_print ("use after %<%s%> of %qE; deleted at %@", | |
1309 | funcname, ev.m_expr, &m_free_event); | |
c7e276b8 DM |
1310 | case WORDING_DEALLOCATED: |
1311 | return ev.formatted_print ("use after %<%s%> of %qE;" | |
1312 | " deallocated at %@", | |
1313 | funcname, ev.m_expr, &m_free_event); | |
1690a839 | 1314 | } |
757bf1df | 1315 | else |
1690a839 DM |
1316 | return ev.formatted_print ("use after %<%s%> of %qE", |
1317 | funcname, ev.m_expr); | |
757bf1df DM |
1318 | } |
1319 | ||
33255ad3 DM |
1320 | /* Implementation of pending_diagnostic::supercedes_p for |
1321 | use_after_free. | |
1322 | ||
1323 | We want use-after-free to supercede use-of-unitialized-value, | |
1324 | so that if we have these at the same stmt, we don't emit | |
1325 | a use-of-uninitialized, just the use-after-free. | |
1326 | (this is because we fully purge information about freed | |
1327 | buffers when we free them to avoid state explosions, so | |
1328 | that if they are accessed after the free, it looks like | |
1329 | they are uninitialized). */ | |
1330 | ||
ff171cb1 | 1331 | bool supercedes_p (const pending_diagnostic &other) const final override |
33255ad3 DM |
1332 | { |
1333 | if (other.use_of_uninit_p ()) | |
1334 | return true; | |
1335 | ||
1336 | return false; | |
1337 | } | |
1338 | ||
757bf1df DM |
1339 | private: |
1340 | diagnostic_event_id_t m_free_event; | |
c7e276b8 | 1341 | const deallocator *m_deallocator; |
757bf1df DM |
1342 | }; |
1343 | ||
1344 | class malloc_leak : public malloc_diagnostic | |
1345 | { | |
1346 | public: | |
1347 | malloc_leak (const malloc_state_machine &sm, tree arg) | |
1348 | : malloc_diagnostic (sm, arg) {} | |
1349 | ||
ff171cb1 | 1350 | const char *get_kind () const final override { return "malloc_leak"; } |
757bf1df | 1351 | |
ff171cb1 | 1352 | int get_controlling_option () const final override |
7fd6e36e DM |
1353 | { |
1354 | return OPT_Wanalyzer_malloc_leak; | |
1355 | } | |
1356 | ||
ff171cb1 | 1357 | bool emit (rich_location *rich_loc) final override |
757bf1df | 1358 | { |
9c603380 | 1359 | /* "CWE-401: Missing Release of Memory after Effective Lifetime". */ |
757bf1df DM |
1360 | diagnostic_metadata m; |
1361 | m.add_cwe (401); | |
808f4dfe | 1362 | if (m_arg) |
7fd6e36e | 1363 | return warning_meta (rich_loc, m, get_controlling_option (), |
808f4dfe DM |
1364 | "leak of %qE", m_arg); |
1365 | else | |
7fd6e36e | 1366 | return warning_meta (rich_loc, m, get_controlling_option (), |
808f4dfe | 1367 | "leak of %qs", "<unknown>"); |
757bf1df DM |
1368 | } |
1369 | ||
1370 | label_text describe_state_change (const evdesc::state_change &change) | |
ff171cb1 | 1371 | final override |
757bf1df | 1372 | { |
c7e276b8 DM |
1373 | if (unchecked_p (change.m_new_state) |
1374 | || (start_p (change.m_old_state) && nonnull_p (change.m_new_state))) | |
757bf1df | 1375 | { |
1690a839 | 1376 | m_alloc_event = change.m_event_id; |
757bf1df DM |
1377 | return label_text::borrow ("allocated here"); |
1378 | } | |
1379 | return malloc_diagnostic::describe_state_change (change); | |
1380 | } | |
1381 | ||
ff171cb1 | 1382 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df | 1383 | { |
808f4dfe DM |
1384 | if (ev.m_expr) |
1385 | { | |
1690a839 | 1386 | if (m_alloc_event.known_p ()) |
808f4dfe | 1387 | return ev.formatted_print ("%qE leaks here; was allocated at %@", |
1690a839 | 1388 | ev.m_expr, &m_alloc_event); |
808f4dfe DM |
1389 | else |
1390 | return ev.formatted_print ("%qE leaks here", ev.m_expr); | |
1391 | } | |
757bf1df | 1392 | else |
808f4dfe | 1393 | { |
1690a839 | 1394 | if (m_alloc_event.known_p ()) |
808f4dfe | 1395 | return ev.formatted_print ("%qs leaks here; was allocated at %@", |
1690a839 | 1396 | "<unknown>", &m_alloc_event); |
808f4dfe DM |
1397 | else |
1398 | return ev.formatted_print ("%qs leaks here", "<unknown>"); | |
1399 | } | |
757bf1df DM |
1400 | } |
1401 | ||
1402 | private: | |
1690a839 | 1403 | diagnostic_event_id_t m_alloc_event; |
757bf1df DM |
1404 | }; |
1405 | ||
1406 | class free_of_non_heap : public malloc_diagnostic | |
1407 | { | |
1408 | public: | |
1690a839 | 1409 | free_of_non_heap (const malloc_state_machine &sm, tree arg, |
a61aaee6 | 1410 | const region *freed_reg, |
1690a839 | 1411 | const char *funcname) |
a61aaee6 | 1412 | : malloc_diagnostic (sm, arg), m_freed_reg (freed_reg), m_funcname (funcname) |
757bf1df DM |
1413 | { |
1414 | } | |
1415 | ||
ff171cb1 | 1416 | const char *get_kind () const final override { return "free_of_non_heap"; } |
757bf1df DM |
1417 | |
1418 | bool subclass_equal_p (const pending_diagnostic &base_other) const | |
ff171cb1 | 1419 | final override |
757bf1df DM |
1420 | { |
1421 | const free_of_non_heap &other = (const free_of_non_heap &)base_other; | |
a61aaee6 DM |
1422 | return (same_tree_p (m_arg, other.m_arg) |
1423 | && m_freed_reg == other.m_freed_reg); | |
757bf1df DM |
1424 | } |
1425 | ||
ff171cb1 | 1426 | int get_controlling_option () const final override |
7fd6e36e DM |
1427 | { |
1428 | return OPT_Wanalyzer_free_of_non_heap; | |
1429 | } | |
1430 | ||
ff171cb1 | 1431 | bool emit (rich_location *rich_loc) final override |
757bf1df DM |
1432 | { |
1433 | auto_diagnostic_group d; | |
1434 | diagnostic_metadata m; | |
1435 | m.add_cwe (590); /* CWE-590: Free of Memory not on the Heap. */ | |
a61aaee6 | 1436 | switch (get_memory_space ()) |
757bf1df DM |
1437 | { |
1438 | default: | |
a61aaee6 | 1439 | case MEMSPACE_HEAP: |
757bf1df | 1440 | gcc_unreachable (); |
a61aaee6 DM |
1441 | case MEMSPACE_UNKNOWN: |
1442 | case MEMSPACE_CODE: | |
1443 | case MEMSPACE_GLOBALS: | |
1444 | case MEMSPACE_READONLY_DATA: | |
7fd6e36e | 1445 | return warning_meta (rich_loc, m, get_controlling_option (), |
1690a839 | 1446 | "%<%s%> of %qE which points to memory" |
6c8e5844 | 1447 | " not on the heap", |
1690a839 | 1448 | m_funcname, m_arg); |
757bf1df | 1449 | break; |
a61aaee6 | 1450 | case MEMSPACE_STACK: |
7fd6e36e | 1451 | return warning_meta (rich_loc, m, get_controlling_option (), |
a61aaee6 DM |
1452 | "%<%s%> of %qE which points to memory" |
1453 | " on the stack", | |
1454 | m_funcname, m_arg); | |
757bf1df DM |
1455 | break; |
1456 | } | |
1457 | } | |
1458 | ||
a61aaee6 | 1459 | label_text describe_state_change (const evdesc::state_change &) |
ff171cb1 | 1460 | final override |
757bf1df | 1461 | { |
757bf1df DM |
1462 | return label_text::borrow ("pointer is from here"); |
1463 | } | |
1464 | ||
ff171cb1 | 1465 | label_text describe_final_event (const evdesc::final_event &ev) final override |
757bf1df | 1466 | { |
1690a839 | 1467 | return ev.formatted_print ("call to %qs here", m_funcname); |
757bf1df DM |
1468 | } |
1469 | ||
ff171cb1 | 1470 | void mark_interesting_stuff (interesting_t *interest) final override |
a61aaee6 DM |
1471 | { |
1472 | if (m_freed_reg) | |
1473 | interest->add_region_creation (m_freed_reg); | |
1474 | } | |
1475 | ||
757bf1df | 1476 | private: |
a61aaee6 | 1477 | enum memory_space get_memory_space () const |
757bf1df | 1478 | { |
a61aaee6 DM |
1479 | if (m_freed_reg) |
1480 | return m_freed_reg->get_memory_space (); | |
1481 | else | |
1482 | return MEMSPACE_UNKNOWN; | |
1483 | } | |
1484 | ||
1485 | const region *m_freed_reg; | |
1690a839 | 1486 | const char *m_funcname; |
757bf1df DM |
1487 | }; |
1488 | ||
5c6546ca DM |
1489 | /* Concrete pending_diagnostic subclass for -Wanalyzer-deref-before-check. */ |
1490 | ||
1491 | class deref_before_check : public malloc_diagnostic | |
1492 | { | |
1493 | public: | |
1494 | deref_before_check (const malloc_state_machine &sm, tree arg) | |
0d6f7b1d DM |
1495 | : malloc_diagnostic (sm, arg), |
1496 | m_deref_enode (NULL), | |
1497 | m_check_enode (NULL) | |
5c6546ca DM |
1498 | {} |
1499 | ||
1500 | const char *get_kind () const final override { return "deref_before_check"; } | |
1501 | ||
1502 | int get_controlling_option () const final override | |
1503 | { | |
1504 | return OPT_Wanalyzer_deref_before_check; | |
1505 | } | |
1506 | ||
1507 | bool emit (rich_location *rich_loc) final override | |
1508 | { | |
0d6f7b1d DM |
1509 | /* Don't emit the warning if we can't show where the deref |
1510 | and the check occur. */ | |
1511 | if (!m_deref_enode) | |
1512 | return false; | |
1513 | if (!m_check_enode) | |
1514 | return false; | |
1515 | /* Only emit the warning for intraprocedural cases. */ | |
1516 | if (m_deref_enode->get_function () != m_check_enode->get_function ()) | |
1517 | return false; | |
1518 | if (&m_deref_enode->get_point ().get_call_string () | |
1519 | != &m_check_enode->get_point ().get_call_string ()) | |
1520 | return false; | |
1521 | ||
1522 | /* Reject the warning if the deref's BB doesn't dominate that | |
1523 | of the check, so that we don't warn e.g. for shared cleanup | |
1524 | code that checks a pointer for NULL, when that code is sometimes | |
1525 | used before a deref and sometimes after. | |
1526 | Using the dominance code requires setting cfun. */ | |
1527 | auto_cfun sentinel (m_deref_enode->get_function ()); | |
1528 | calculate_dominance_info (CDI_DOMINATORS); | |
1529 | if (!dominated_by_p (CDI_DOMINATORS, | |
1530 | m_check_enode->get_supernode ()->m_bb, | |
1531 | m_deref_enode->get_supernode ()->m_bb)) | |
1532 | return false; | |
1533 | ||
5c6546ca DM |
1534 | if (m_arg) |
1535 | return warning_at (rich_loc, get_controlling_option (), | |
1536 | "check of %qE for NULL after already" | |
1537 | " dereferencing it", | |
1538 | m_arg); | |
1539 | else | |
1540 | return warning_at (rich_loc, get_controlling_option (), | |
1541 | "check of pointer for NULL after already" | |
1542 | " dereferencing it"); | |
1543 | } | |
1544 | ||
1545 | label_text describe_state_change (const evdesc::state_change &change) | |
1546 | final override | |
1547 | { | |
1548 | if (change.m_old_state == m_sm.get_start_state () | |
1549 | && assumed_non_null_p (change.m_new_state)) | |
1550 | { | |
1551 | m_first_deref_event = change.m_event_id; | |
0d6f7b1d | 1552 | m_deref_enode = change.m_event.get_exploded_node (); |
5c6546ca DM |
1553 | if (m_arg) |
1554 | return change.formatted_print ("pointer %qE is dereferenced here", | |
1555 | m_arg); | |
1556 | else | |
1557 | return label_text::borrow ("pointer is dereferenced here"); | |
1558 | } | |
1559 | return malloc_diagnostic::describe_state_change (change); | |
1560 | } | |
1561 | ||
1562 | label_text describe_final_event (const evdesc::final_event &ev) final override | |
1563 | { | |
0d6f7b1d | 1564 | m_check_enode = ev.m_event.get_exploded_node (); |
5c6546ca DM |
1565 | if (m_first_deref_event.known_p ()) |
1566 | { | |
1567 | if (m_arg) | |
1568 | return ev.formatted_print ("pointer %qE is checked for NULL here but" | |
1569 | " it was already dereferenced at %@", | |
1570 | m_arg, &m_first_deref_event); | |
1571 | else | |
1572 | return ev.formatted_print ("pointer is checked for NULL here but" | |
1573 | " it was already dereferenced at %@", | |
1574 | &m_first_deref_event); | |
1575 | } | |
1576 | else | |
1577 | { | |
1578 | if (m_arg) | |
1579 | return ev.formatted_print ("pointer %qE is checked for NULL here but" | |
1580 | " it was already dereferenced", | |
1581 | m_arg); | |
1582 | else | |
1583 | return ev.formatted_print ("pointer is checked for NULL here but" | |
1584 | " it was already dereferenced"); | |
1585 | } | |
1586 | } | |
1587 | ||
1588 | private: | |
1589 | diagnostic_event_id_t m_first_deref_event; | |
0d6f7b1d DM |
1590 | const exploded_node *m_deref_enode; |
1591 | const exploded_node *m_check_enode; | |
5c6546ca DM |
1592 | }; |
1593 | ||
1690a839 DM |
1594 | /* struct allocation_state : public state_machine::state. */ |
1595 | ||
1596 | /* Implementation of state_machine::state::dump_to_pp vfunc | |
1597 | for allocation_state: append the API that this allocation is | |
1598 | associated with. */ | |
1599 | ||
1600 | void | |
1601 | allocation_state::dump_to_pp (pretty_printer *pp) const | |
1602 | { | |
1603 | state_machine::state::dump_to_pp (pp); | |
c7e276b8 DM |
1604 | if (m_deallocators) |
1605 | { | |
1606 | pp_string (pp, " ("); | |
1607 | m_deallocators->dump_to_pp (pp); | |
1608 | pp_character (pp, ')'); | |
1609 | } | |
1690a839 DM |
1610 | } |
1611 | ||
c7e276b8 DM |
1612 | /* Given a allocation_state for a deallocator_set, get the "nonnull" state |
1613 | for the corresponding allocator(s). */ | |
1690a839 DM |
1614 | |
1615 | const allocation_state * | |
1616 | allocation_state::get_nonnull () const | |
1617 | { | |
c7e276b8 DM |
1618 | gcc_assert (m_deallocators); |
1619 | return as_a_allocation_state (m_deallocators->m_nonnull); | |
1690a839 DM |
1620 | } |
1621 | ||
5c6546ca DM |
1622 | /* struct assumed_non_null_state : public allocation_state. */ |
1623 | ||
1624 | void | |
1625 | assumed_non_null_state::dump_to_pp (pretty_printer *pp) const | |
1626 | { | |
1627 | allocation_state::dump_to_pp (pp); | |
1628 | pp_string (pp, " (in "); | |
1629 | m_frame->dump_to_pp (pp, true); | |
1630 | pp_character (pp, ')'); | |
1631 | } | |
1632 | ||
757bf1df DM |
1633 | /* malloc_state_machine's ctor. */ |
1634 | ||
1635 | malloc_state_machine::malloc_state_machine (logger *logger) | |
1690a839 | 1636 | : state_machine ("malloc", logger), |
c7e276b8 DM |
1637 | m_free (this, "free", WORDING_FREED), |
1638 | m_scalar_delete (this, "delete", WORDING_DELETED), | |
a6baafca DM |
1639 | m_vector_delete (this, "delete[]", WORDING_DELETED), |
1640 | m_realloc (this, "realloc", WORDING_REALLOCATED) | |
1690a839 DM |
1641 | { |
1642 | gcc_assert (m_start->get_id () == 0); | |
c7e276b8 DM |
1643 | m_null = add_state ("null", RS_FREED, NULL, NULL); |
1644 | m_non_heap = add_state ("non-heap", RS_NON_HEAP, NULL, NULL); | |
1645 | m_stop = add_state ("stop", RS_STOP, NULL, NULL); | |
1646 | } | |
1647 | ||
1648 | malloc_state_machine::~malloc_state_machine () | |
1649 | { | |
1650 | unsigned i; | |
1651 | custom_deallocator_set *set; | |
1652 | FOR_EACH_VEC_ELT (m_dynamic_sets, i, set) | |
1653 | delete set; | |
1654 | custom_deallocator *d; | |
1655 | FOR_EACH_VEC_ELT (m_dynamic_deallocators, i, d) | |
1656 | delete d; | |
1690a839 DM |
1657 | } |
1658 | ||
1659 | state_machine::state_t | |
1660 | malloc_state_machine::add_state (const char *name, enum resource_state rs, | |
c7e276b8 DM |
1661 | const deallocator_set *deallocators, |
1662 | const deallocator *deallocator) | |
1690a839 DM |
1663 | { |
1664 | return add_custom_state (new allocation_state (name, alloc_state_id (), | |
c7e276b8 DM |
1665 | rs, deallocators, |
1666 | deallocator)); | |
1667 | } | |
1668 | ||
1669 | /* If ALLOCATOR_FNDECL has any "__attribute__((malloc(FOO)))", | |
1670 | return a custom_deallocator_set for them, consolidating them | |
1671 | to ensure uniqueness of the sets. | |
1672 | ||
1673 | Return NULL if it has no such attributes. */ | |
1674 | ||
1675 | const custom_deallocator_set * | |
1676 | malloc_state_machine:: | |
1677 | get_or_create_custom_deallocator_set (tree allocator_fndecl) | |
1678 | { | |
1679 | /* Early rejection of decls without attributes. */ | |
1680 | tree attrs = DECL_ATTRIBUTES (allocator_fndecl); | |
1681 | if (!attrs) | |
1682 | return NULL; | |
1683 | ||
1684 | /* Otherwise, call maybe_create_custom_deallocator_set, | |
1685 | memoizing the result. */ | |
1686 | if (custom_deallocator_set **slot | |
1687 | = m_custom_deallocator_set_cache.get (allocator_fndecl)) | |
1688 | return *slot; | |
1689 | custom_deallocator_set *set | |
1690 | = maybe_create_custom_deallocator_set (allocator_fndecl); | |
1691 | m_custom_deallocator_set_cache.put (allocator_fndecl, set); | |
1692 | return set; | |
1693 | } | |
1694 | ||
1695 | /* Given ALLOCATOR_FNDECL, a FUNCTION_DECL with attributes, | |
1696 | look for any "__attribute__((malloc(FOO)))" and return a | |
1697 | custom_deallocator_set for them, consolidating them | |
1698 | to ensure uniqueness of the sets. | |
1699 | ||
1700 | Return NULL if it has no such attributes. | |
1701 | ||
1702 | Subroutine of get_or_create_custom_deallocator_set which | |
1703 | memoizes the result. */ | |
1704 | ||
1705 | custom_deallocator_set * | |
1706 | malloc_state_machine:: | |
1707 | maybe_create_custom_deallocator_set (tree allocator_fndecl) | |
1708 | { | |
1709 | tree attrs = DECL_ATTRIBUTES (allocator_fndecl); | |
1710 | gcc_assert (attrs); | |
1711 | ||
1712 | /* Look for instances of __attribute__((malloc(FOO))). */ | |
1713 | auto_vec<const deallocator *> deallocator_vec; | |
1714 | for (tree allocs = attrs; | |
1715 | (allocs = lookup_attribute ("malloc", allocs)); | |
1716 | allocs = TREE_CHAIN (allocs)) | |
1717 | { | |
1718 | tree args = TREE_VALUE (allocs); | |
1719 | if (!args) | |
1720 | continue; | |
1721 | if (TREE_VALUE (args)) | |
1722 | { | |
1723 | const deallocator *d | |
1724 | = get_or_create_deallocator (TREE_VALUE (args)); | |
1725 | deallocator_vec.safe_push (d); | |
1726 | } | |
1727 | } | |
1728 | ||
1729 | /* If there weren't any deallocators, bail. */ | |
1730 | if (deallocator_vec.length () == 0) | |
1731 | return NULL; | |
1732 | ||
1733 | /* Consolidate, so that we reuse existing deallocator_set | |
1734 | instances. */ | |
1735 | deallocator_vec.qsort (deallocator::cmp_ptr_ptr); | |
1736 | custom_deallocator_set **slot | |
1737 | = m_custom_deallocator_set_map.get (&deallocator_vec); | |
1738 | if (slot) | |
1739 | return *slot; | |
1740 | custom_deallocator_set *set | |
1741 | = new custom_deallocator_set (this, &deallocator_vec, WORDING_DEALLOCATED); | |
1742 | m_custom_deallocator_set_map.put (&set->m_deallocator_vec, set); | |
1743 | m_dynamic_sets.safe_push (set); | |
1744 | return set; | |
1745 | } | |
1746 | ||
1747 | /* Get the deallocator for DEALLOCATOR_FNDECL, creating it if necessary. */ | |
1748 | ||
1749 | const deallocator * | |
1750 | malloc_state_machine::get_or_create_deallocator (tree deallocator_fndecl) | |
1751 | { | |
1752 | deallocator **slot = m_deallocator_map.get (deallocator_fndecl); | |
1753 | if (slot) | |
1754 | return *slot; | |
1755 | ||
1756 | /* Reuse "free". */ | |
1757 | deallocator *d; | |
1758 | if (is_named_call_p (deallocator_fndecl, "free") | |
84606efb SP |
1759 | || is_std_named_call_p (deallocator_fndecl, "free") |
1760 | || is_named_call_p (deallocator_fndecl, "__builtin_free")) | |
c7e276b8 DM |
1761 | d = &m_free.m_deallocator; |
1762 | else | |
1763 | { | |
1764 | custom_deallocator *cd | |
1765 | = new custom_deallocator (this, deallocator_fndecl, | |
1766 | WORDING_DEALLOCATED); | |
1767 | m_dynamic_deallocators.safe_push (cd); | |
1768 | d = cd; | |
1769 | } | |
1770 | m_deallocator_map.put (deallocator_fndecl, d); | |
1771 | return d; | |
757bf1df DM |
1772 | } |
1773 | ||
5c6546ca DM |
1774 | /* Get the "assumed-non-null" state for assumptions made within FRAME, |
1775 | creating it if necessary. */ | |
1776 | ||
1777 | state_machine::state_t | |
1778 | malloc_state_machine:: | |
1779 | get_or_create_assumed_non_null_state_for_frame (const frame_region *frame) | |
1780 | { | |
1781 | if (state_t *slot = m_assumed_non_null.get (frame)) | |
1782 | return *slot; | |
1783 | state_machine::state *new_state | |
1784 | = new assumed_non_null_state ("assumed-non-null", alloc_state_id (), frame); | |
1785 | add_custom_state (new_state); | |
1786 | m_assumed_non_null.put (frame, new_state); | |
1787 | return new_state; | |
1788 | } | |
1789 | ||
31534ac2 SP |
1790 | /* Try to identify the function declaration either by name or as a known malloc |
1791 | builtin. */ | |
1792 | ||
1793 | static bool | |
1794 | known_allocator_p (const_tree fndecl, const gcall *call) | |
1795 | { | |
1796 | /* Either it is a function we know by name and number of arguments... */ | |
1797 | if (is_named_call_p (fndecl, "malloc", call, 1) | |
1798 | || is_named_call_p (fndecl, "calloc", call, 2) | |
1799 | || is_std_named_call_p (fndecl, "malloc", call, 1) | |
1800 | || is_std_named_call_p (fndecl, "calloc", call, 2) | |
1801 | || is_named_call_p (fndecl, "strdup", call, 1) | |
1802 | || is_named_call_p (fndecl, "strndup", call, 2)) | |
1803 | return true; | |
1804 | ||
1805 | /* ... or it is a builtin allocator that allocates objects freed with | |
1806 | __builtin_free. */ | |
1a830c06 | 1807 | if (fndecl_built_in_p (fndecl, BUILT_IN_NORMAL)) |
31534ac2 SP |
1808 | switch (DECL_FUNCTION_CODE (fndecl)) |
1809 | { | |
1810 | case BUILT_IN_MALLOC: | |
1811 | case BUILT_IN_CALLOC: | |
1812 | case BUILT_IN_STRDUP: | |
1813 | case BUILT_IN_STRNDUP: | |
1814 | return true; | |
1815 | default: | |
1816 | break; | |
1817 | } | |
1818 | ||
1819 | return false; | |
1820 | } | |
1821 | ||
5c6546ca DM |
1822 | /* If PTR's nullness is not known, transition it to the "assumed-non-null" |
1823 | state for the current frame. */ | |
1824 | ||
1825 | void | |
1826 | malloc_state_machine::maybe_assume_non_null (sm_context *sm_ctxt, | |
1827 | tree ptr, | |
1828 | const gimple *stmt) const | |
1829 | { | |
1830 | const region_model *old_model = sm_ctxt->get_old_region_model (); | |
1831 | if (!old_model) | |
1832 | return; | |
1833 | ||
1834 | tree null_ptr_cst = build_int_cst (TREE_TYPE (ptr), 0); | |
1835 | tristate known_non_null | |
1836 | = old_model->eval_condition (ptr, NE_EXPR, null_ptr_cst, NULL); | |
1837 | if (known_non_null.is_unknown ()) | |
1838 | { | |
1839 | /* Cast away const-ness for cache-like operations. */ | |
1840 | malloc_state_machine *mut_this | |
1841 | = const_cast <malloc_state_machine *> (this); | |
1842 | state_t next_state | |
1843 | = mut_this->get_or_create_assumed_non_null_state_for_frame | |
1844 | (old_model->get_current_frame ()); | |
1845 | sm_ctxt->set_next_state (stmt, ptr, next_state); | |
1846 | } | |
1847 | } | |
1848 | ||
757bf1df DM |
1849 | /* Implementation of state_machine::on_stmt vfunc for malloc_state_machine. */ |
1850 | ||
1851 | bool | |
1852 | malloc_state_machine::on_stmt (sm_context *sm_ctxt, | |
1853 | const supernode *node, | |
1854 | const gimple *stmt) const | |
1855 | { | |
1856 | if (const gcall *call = dyn_cast <const gcall *> (stmt)) | |
1857 | if (tree callee_fndecl = sm_ctxt->get_fndecl_for_call (call)) | |
1858 | { | |
31534ac2 | 1859 | if (known_allocator_p (callee_fndecl, call)) |
757bf1df | 1860 | { |
c7e276b8 | 1861 | on_allocator_call (sm_ctxt, call, &m_free); |
1690a839 DM |
1862 | return true; |
1863 | } | |
1864 | ||
1865 | if (is_named_call_p (callee_fndecl, "operator new", call, 1)) | |
c7e276b8 | 1866 | on_allocator_call (sm_ctxt, call, &m_scalar_delete); |
1690a839 | 1867 | else if (is_named_call_p (callee_fndecl, "operator new []", call, 1)) |
c7e276b8 | 1868 | on_allocator_call (sm_ctxt, call, &m_vector_delete); |
1690a839 DM |
1869 | else if (is_named_call_p (callee_fndecl, "operator delete", call, 1) |
1870 | || is_named_call_p (callee_fndecl, "operator delete", call, 2)) | |
1871 | { | |
c7e276b8 DM |
1872 | on_deallocator_call (sm_ctxt, node, call, |
1873 | &m_scalar_delete.m_deallocator, 0); | |
1690a839 DM |
1874 | return true; |
1875 | } | |
1876 | else if (is_named_call_p (callee_fndecl, "operator delete []", call, 1)) | |
1877 | { | |
c7e276b8 DM |
1878 | on_deallocator_call (sm_ctxt, node, call, |
1879 | &m_vector_delete.m_deallocator, 0); | |
757bf1df DM |
1880 | return true; |
1881 | } | |
1882 | ||
1883 | if (is_named_call_p (callee_fndecl, "alloca", call, 1) | |
1884 | || is_named_call_p (callee_fndecl, "__builtin_alloca", call, 1)) | |
1885 | { | |
1886 | tree lhs = gimple_call_lhs (call); | |
1887 | if (lhs) | |
808f4dfe | 1888 | sm_ctxt->on_transition (node, stmt, lhs, m_start, m_non_heap); |
757bf1df DM |
1889 | return true; |
1890 | } | |
1891 | ||
1892 | if (is_named_call_p (callee_fndecl, "free", call, 1) | |
9f00b22f | 1893 | || is_std_named_call_p (callee_fndecl, "free", call, 1) |
757bf1df DM |
1894 | || is_named_call_p (callee_fndecl, "__builtin_free", call, 1)) |
1895 | { | |
c7e276b8 DM |
1896 | on_deallocator_call (sm_ctxt, node, call, |
1897 | &m_free.m_deallocator, 0); | |
757bf1df DM |
1898 | return true; |
1899 | } | |
1900 | ||
a6baafca DM |
1901 | if (is_named_call_p (callee_fndecl, "realloc", call, 2) |
1902 | || is_named_call_p (callee_fndecl, "__builtin_realloc", call, 2)) | |
1903 | { | |
1904 | on_realloc_call (sm_ctxt, node, call); | |
1905 | return true; | |
1906 | } | |
1907 | ||
cd323d97 DM |
1908 | if (unaffected_by_call_p (callee_fndecl)) |
1909 | return true; | |
1910 | ||
c7e276b8 DM |
1911 | /* Cast away const-ness for cache-like operations. */ |
1912 | malloc_state_machine *mutable_this | |
1913 | = const_cast <malloc_state_machine *> (this); | |
1914 | ||
1915 | /* Handle "__attribute__((malloc(FOO)))". */ | |
1916 | if (const deallocator_set *deallocators | |
1917 | = mutable_this->get_or_create_custom_deallocator_set | |
1918 | (callee_fndecl)) | |
1919 | { | |
1920 | tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (callee_fndecl)); | |
1921 | bool returns_nonnull | |
1922 | = lookup_attribute ("returns_nonnull", attrs); | |
1923 | on_allocator_call (sm_ctxt, call, deallocators, returns_nonnull); | |
1924 | } | |
1925 | ||
757bf1df DM |
1926 | /* Handle "__attribute__((nonnull))". */ |
1927 | { | |
1928 | tree fntype = TREE_TYPE (callee_fndecl); | |
1929 | bitmap nonnull_args = get_nonnull_args (fntype); | |
1930 | if (nonnull_args) | |
1931 | { | |
1932 | for (unsigned i = 0; i < gimple_call_num_args (stmt); i++) | |
1933 | { | |
1934 | tree arg = gimple_call_arg (stmt, i); | |
1935 | if (TREE_CODE (TREE_TYPE (arg)) != POINTER_TYPE) | |
1936 | continue; | |
1937 | /* If we have a nonnull-args, and either all pointers, or just | |
1938 | the specified pointers. */ | |
1939 | if (bitmap_empty_p (nonnull_args) | |
1940 | || bitmap_bit_p (nonnull_args, i)) | |
1941 | { | |
25ef215a DM |
1942 | state_t state = sm_ctxt->get_state (stmt, arg); |
1943 | /* Can't use a switch as the states are non-const. */ | |
1690a839 | 1944 | if (unchecked_p (state)) |
25ef215a | 1945 | { |
7d8f4240 | 1946 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
25ef215a | 1947 | sm_ctxt->warn (node, stmt, arg, |
6341f14e DM |
1948 | make_unique<possible_null_arg> |
1949 | (*this, diag_arg, callee_fndecl, i)); | |
1690a839 DM |
1950 | const allocation_state *astate |
1951 | = as_a_allocation_state (state); | |
1952 | sm_ctxt->set_next_state (stmt, arg, | |
1953 | astate->get_nonnull ()); | |
25ef215a DM |
1954 | } |
1955 | else if (state == m_null) | |
1956 | { | |
7d8f4240 | 1957 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
25ef215a | 1958 | sm_ctxt->warn (node, stmt, arg, |
6341f14e DM |
1959 | make_unique<null_arg> |
1960 | (*this, diag_arg, callee_fndecl, i)); | |
25ef215a DM |
1961 | sm_ctxt->set_next_state (stmt, arg, m_stop); |
1962 | } | |
5c6546ca DM |
1963 | else if (state == m_start) |
1964 | maybe_assume_non_null (sm_ctxt, arg, stmt); | |
757bf1df DM |
1965 | } |
1966 | } | |
1967 | BITMAP_FREE (nonnull_args); | |
1968 | } | |
1969 | } | |
c7e276b8 DM |
1970 | |
1971 | /* Check for this after nonnull, so that if we have both | |
1972 | then we transition to "freed", rather than "checked". */ | |
1973 | unsigned dealloc_argno = fndecl_dealloc_argno (callee_fndecl); | |
1974 | if (dealloc_argno != UINT_MAX) | |
1975 | { | |
1976 | const deallocator *d | |
1977 | = mutable_this->get_or_create_deallocator (callee_fndecl); | |
1978 | on_deallocator_call (sm_ctxt, node, call, d, dealloc_argno); | |
1979 | } | |
757bf1df DM |
1980 | } |
1981 | ||
5c6546ca DM |
1982 | /* Look for pointers explicitly being compared against zero |
1983 | that are in state assumed_non_null i.e. we already defererenced | |
1984 | them. | |
1985 | We have to do this check here, rather than in on_condition | |
1986 | because we add a constraint that the pointer is non-null when | |
1987 | dereferencing it, and this makes the apply_constraints_for_gcond | |
1988 | find known-true and known-false conditions; on_condition is only | |
1989 | called when adding new constraints. */ | |
1990 | if (const gcond *cond_stmt = dyn_cast <const gcond *> (stmt)) | |
1991 | { | |
1992 | enum tree_code op = gimple_cond_code (cond_stmt); | |
1993 | if (op == EQ_EXPR || op == NE_EXPR) | |
1994 | { | |
1995 | tree lhs = gimple_cond_lhs (cond_stmt); | |
1996 | tree rhs = gimple_cond_rhs (cond_stmt); | |
1997 | if (any_pointer_p (lhs) | |
1998 | && any_pointer_p (rhs) | |
1999 | && zerop (rhs)) | |
2000 | { | |
2001 | state_t state = sm_ctxt->get_state (stmt, lhs); | |
2002 | if (assumed_non_null_p (state)) | |
2003 | maybe_complain_about_deref_before_check | |
2004 | (sm_ctxt, node, | |
2005 | stmt, | |
2006 | (const assumed_non_null_state *)state, | |
2007 | lhs); | |
2008 | } | |
2009 | } | |
2010 | } | |
2011 | ||
808f4dfe | 2012 | if (tree lhs = sm_ctxt->is_zero_assignment (stmt)) |
8525d1f5 | 2013 | if (any_pointer_p (lhs)) |
1690a839 | 2014 | on_zero_assignment (sm_ctxt, stmt,lhs); |
757bf1df | 2015 | |
757bf1df DM |
2016 | /* Handle dereferences. */ |
2017 | for (unsigned i = 0; i < gimple_num_ops (stmt); i++) | |
2018 | { | |
2019 | tree op = gimple_op (stmt, i); | |
2020 | if (!op) | |
2021 | continue; | |
2022 | if (TREE_CODE (op) == COMPONENT_REF) | |
2023 | op = TREE_OPERAND (op, 0); | |
2024 | ||
2025 | if (TREE_CODE (op) == MEM_REF) | |
2026 | { | |
2027 | tree arg = TREE_OPERAND (op, 0); | |
757bf1df | 2028 | |
25ef215a | 2029 | state_t state = sm_ctxt->get_state (stmt, arg); |
5c6546ca DM |
2030 | if (state == m_start) |
2031 | maybe_assume_non_null (sm_ctxt, arg, stmt); | |
2032 | else if (unchecked_p (state)) | |
25ef215a | 2033 | { |
0f9aa35c | 2034 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
25ef215a | 2035 | sm_ctxt->warn (node, stmt, arg, |
6341f14e DM |
2036 | make_unique<possible_null_deref> (*this, |
2037 | diag_arg)); | |
1690a839 DM |
2038 | const allocation_state *astate = as_a_allocation_state (state); |
2039 | sm_ctxt->set_next_state (stmt, arg, astate->get_nonnull ()); | |
25ef215a DM |
2040 | } |
2041 | else if (state == m_null) | |
2042 | { | |
0f9aa35c | 2043 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
25ef215a | 2044 | sm_ctxt->warn (node, stmt, arg, |
6341f14e | 2045 | make_unique<null_deref> (*this, diag_arg)); |
25ef215a DM |
2046 | sm_ctxt->set_next_state (stmt, arg, m_stop); |
2047 | } | |
1690a839 | 2048 | else if (freed_p (state)) |
25ef215a | 2049 | { |
0f9aa35c | 2050 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
1690a839 | 2051 | const allocation_state *astate = as_a_allocation_state (state); |
25ef215a | 2052 | sm_ctxt->warn (node, stmt, arg, |
6341f14e DM |
2053 | make_unique<use_after_free> |
2054 | (*this, diag_arg, astate->m_deallocator)); | |
25ef215a DM |
2055 | sm_ctxt->set_next_state (stmt, arg, m_stop); |
2056 | } | |
757bf1df DM |
2057 | } |
2058 | } | |
2059 | return false; | |
2060 | } | |
2061 | ||
5c6546ca DM |
2062 | /* Given a check against null of PTR in assumed-non-null state STATE, |
2063 | potentially add a deref_before_check warning to SM_CTXT. */ | |
2064 | ||
2065 | void | |
2066 | malloc_state_machine:: | |
2067 | maybe_complain_about_deref_before_check (sm_context *sm_ctxt, | |
2068 | const supernode *node, | |
2069 | const gimple *stmt, | |
2070 | const assumed_non_null_state *state, | |
2071 | tree ptr) const | |
2072 | { | |
2073 | const region_model *model = sm_ctxt->get_old_region_model (); | |
2074 | if (!model) | |
2075 | return; | |
2076 | ||
2077 | /* Don't complain if the current frame (where the check is occurring) is | |
2078 | deeper than the frame in which the "not null" assumption was made. | |
2079 | This suppress false positives for cases like: | |
2080 | ||
2081 | void foo (struct s *p) | |
2082 | { | |
2083 | int val = s->some_field; // deref here | |
2084 | shared_helper (p); | |
2085 | } | |
2086 | ||
2087 | where "shared_helper" has: | |
2088 | ||
2089 | void shared_helper (struct s *p) | |
2090 | { | |
2091 | if (!p) // check here | |
2092 | return; | |
2093 | // etc | |
2094 | } | |
2095 | ||
2096 | since the check in "shared_helper" is OK. */ | |
2097 | const frame_region *checked_in_frame = model->get_current_frame (); | |
2098 | const frame_region *assumed_nonnull_in_frame = state->m_frame; | |
2099 | if (checked_in_frame->get_index () > assumed_nonnull_in_frame->get_index ()) | |
2100 | return; | |
2101 | ||
2102 | tree diag_ptr = sm_ctxt->get_diagnostic_tree (ptr); | |
2103 | sm_ctxt->warn | |
2104 | (node, stmt, ptr, | |
2105 | make_unique<deref_before_check> (*this, diag_ptr)); | |
2106 | sm_ctxt->set_next_state (stmt, ptr, m_stop); | |
2107 | } | |
2108 | ||
c7e276b8 DM |
2109 | /* Handle a call to an allocator. |
2110 | RETURNS_NONNULL is true if CALL is to a fndecl known to have | |
2111 | __attribute__((returns_nonnull)). */ | |
1690a839 DM |
2112 | |
2113 | void | |
2114 | malloc_state_machine::on_allocator_call (sm_context *sm_ctxt, | |
2115 | const gcall *call, | |
c7e276b8 DM |
2116 | const deallocator_set *deallocators, |
2117 | bool returns_nonnull) const | |
1690a839 DM |
2118 | { |
2119 | tree lhs = gimple_call_lhs (call); | |
2120 | if (lhs) | |
2121 | { | |
2122 | if (sm_ctxt->get_state (call, lhs) == m_start) | |
c7e276b8 DM |
2123 | sm_ctxt->set_next_state (call, lhs, |
2124 | (returns_nonnull | |
2125 | ? deallocators->m_nonnull | |
2126 | : deallocators->m_unchecked)); | |
1690a839 DM |
2127 | } |
2128 | else | |
2129 | { | |
2130 | /* TODO: report leak. */ | |
2131 | } | |
2132 | } | |
2133 | ||
a61aaee6 DM |
2134 | /* Handle deallocations of non-heap pointers. |
2135 | non-heap -> stop, with warning. */ | |
2136 | ||
2137 | void | |
2138 | malloc_state_machine::handle_free_of_non_heap (sm_context *sm_ctxt, | |
2139 | const supernode *node, | |
2140 | const gcall *call, | |
2141 | tree arg, | |
2142 | const deallocator *d) const | |
2143 | { | |
2144 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); | |
2145 | const region *freed_reg = NULL; | |
2146 | if (const program_state *old_state = sm_ctxt->get_old_program_state ()) | |
2147 | { | |
2148 | const region_model *old_model = old_state->m_region_model; | |
2149 | const svalue *ptr_sval = old_model->get_rvalue (arg, NULL); | |
2150 | freed_reg = old_model->deref_rvalue (ptr_sval, arg, NULL); | |
2151 | } | |
2152 | sm_ctxt->warn (node, call, arg, | |
6341f14e DM |
2153 | make_unique<free_of_non_heap> |
2154 | (*this, diag_arg, freed_reg, d->m_name)); | |
a61aaee6 DM |
2155 | sm_ctxt->set_next_state (call, arg, m_stop); |
2156 | } | |
2157 | ||
1690a839 DM |
2158 | void |
2159 | malloc_state_machine::on_deallocator_call (sm_context *sm_ctxt, | |
2160 | const supernode *node, | |
2161 | const gcall *call, | |
c7e276b8 DM |
2162 | const deallocator *d, |
2163 | unsigned argno) const | |
1690a839 | 2164 | { |
c7e276b8 DM |
2165 | if (argno >= gimple_call_num_args (call)) |
2166 | return; | |
2167 | tree arg = gimple_call_arg (call, argno); | |
1690a839 DM |
2168 | |
2169 | state_t state = sm_ctxt->get_state (call, arg); | |
2170 | ||
5c6546ca DM |
2171 | /* start/assumed_non_null/unchecked/nonnull -> freed. */ |
2172 | if (state == m_start || assumed_non_null_p (state)) | |
c7e276b8 | 2173 | sm_ctxt->set_next_state (call, arg, d->m_freed); |
1690a839 DM |
2174 | else if (unchecked_p (state) || nonnull_p (state)) |
2175 | { | |
2176 | const allocation_state *astate = as_a_allocation_state (state); | |
c7e276b8 DM |
2177 | gcc_assert (astate->m_deallocators); |
2178 | if (!astate->m_deallocators->contains_p (d)) | |
1690a839 DM |
2179 | { |
2180 | /* Wrong allocator. */ | |
0f9aa35c | 2181 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
6341f14e DM |
2182 | sm_ctxt->warn (node, call, arg, |
2183 | make_unique<mismatching_deallocation> | |
2184 | (*this, diag_arg, | |
2185 | astate->m_deallocators, | |
2186 | d)); | |
1690a839 | 2187 | } |
c7e276b8 | 2188 | sm_ctxt->set_next_state (call, arg, d->m_freed); |
1690a839 DM |
2189 | } |
2190 | ||
2191 | /* Keep state "null" as-is, rather than transitioning to "freed"; | |
2192 | we don't want to complain about double-free of NULL. */ | |
c7e276b8 | 2193 | else if (state == d->m_freed) |
1690a839 DM |
2194 | { |
2195 | /* freed -> stop, with warning. */ | |
0f9aa35c | 2196 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
1690a839 | 2197 | sm_ctxt->warn (node, call, arg, |
6341f14e | 2198 | make_unique<double_free> (*this, diag_arg, d->m_name)); |
1690a839 DM |
2199 | sm_ctxt->set_next_state (call, arg, m_stop); |
2200 | } | |
2201 | else if (state == m_non_heap) | |
2202 | { | |
2203 | /* non-heap -> stop, with warning. */ | |
a61aaee6 | 2204 | handle_free_of_non_heap (sm_ctxt, node, call, arg, d); |
1690a839 DM |
2205 | } |
2206 | } | |
2207 | ||
eafa9d96 DM |
2208 | /* Handle a call to "realloc". |
2209 | Check for free of non-heap or mismatching allocators, | |
2210 | transitioning to the "stop" state for such cases. | |
a6baafca | 2211 | |
6bd31b33 | 2212 | Otherwise, kf_realloc::impl_call_post will later |
eafa9d96 DM |
2213 | get called (which will handle other sm-state transitions |
2214 | when the state is bifurcated). */ | |
a6baafca DM |
2215 | |
2216 | void | |
2217 | malloc_state_machine::on_realloc_call (sm_context *sm_ctxt, | |
eafa9d96 | 2218 | const supernode *node, |
a6baafca DM |
2219 | const gcall *call) const |
2220 | { | |
eafa9d96 DM |
2221 | const unsigned argno = 0; |
2222 | const deallocator *d = &m_realloc; | |
2223 | ||
2224 | tree arg = gimple_call_arg (call, argno); | |
a6baafca | 2225 | |
eafa9d96 | 2226 | state_t state = sm_ctxt->get_state (call, arg); |
a6baafca | 2227 | |
a6baafca DM |
2228 | if (unchecked_p (state) || nonnull_p (state)) |
2229 | { | |
2230 | const allocation_state *astate = as_a_allocation_state (state); | |
2231 | gcc_assert (astate->m_deallocators); | |
eafa9d96 | 2232 | if (!astate->m_deallocators->contains_p (&m_free.m_deallocator)) |
a6baafca DM |
2233 | { |
2234 | /* Wrong allocator. */ | |
eafa9d96 | 2235 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); |
6341f14e DM |
2236 | sm_ctxt->warn (node, call, arg, |
2237 | make_unique<mismatching_deallocation> | |
2238 | (*this, diag_arg, | |
2239 | astate->m_deallocators, d)); | |
eafa9d96 DM |
2240 | sm_ctxt->set_next_state (call, arg, m_stop); |
2241 | if (path_context *path_ctxt = sm_ctxt->get_path_context ()) | |
2242 | path_ctxt->terminate_path (); | |
a6baafca DM |
2243 | } |
2244 | } | |
eafa9d96 DM |
2245 | else if (state == m_free.m_deallocator.m_freed) |
2246 | { | |
2247 | /* freed -> stop, with warning. */ | |
2248 | tree diag_arg = sm_ctxt->get_diagnostic_tree (arg); | |
2249 | sm_ctxt->warn (node, call, arg, | |
6341f14e | 2250 | make_unique<double_free> (*this, diag_arg, "free")); |
eafa9d96 DM |
2251 | sm_ctxt->set_next_state (call, arg, m_stop); |
2252 | if (path_context *path_ctxt = sm_ctxt->get_path_context ()) | |
2253 | path_ctxt->terminate_path (); | |
2254 | } | |
2255 | else if (state == m_non_heap) | |
2256 | { | |
2257 | /* non-heap -> stop, with warning. */ | |
a61aaee6 | 2258 | handle_free_of_non_heap (sm_ctxt, node, call, arg, d); |
eafa9d96 DM |
2259 | if (path_context *path_ctxt = sm_ctxt->get_path_context ()) |
2260 | path_ctxt->terminate_path (); | |
2261 | } | |
a6baafca DM |
2262 | } |
2263 | ||
8525d1f5 DM |
2264 | /* Implementation of state_machine::on_phi vfunc for malloc_state_machine. */ |
2265 | ||
2266 | void | |
2267 | malloc_state_machine::on_phi (sm_context *sm_ctxt, | |
1690a839 | 2268 | const supernode *node ATTRIBUTE_UNUSED, |
8525d1f5 DM |
2269 | const gphi *phi, |
2270 | tree rhs) const | |
2271 | { | |
2272 | if (zerop (rhs)) | |
2273 | { | |
2274 | tree lhs = gimple_phi_result (phi); | |
1690a839 | 2275 | on_zero_assignment (sm_ctxt, phi, lhs); |
8525d1f5 DM |
2276 | } |
2277 | } | |
2278 | ||
757bf1df DM |
2279 | /* Implementation of state_machine::on_condition vfunc for malloc_state_machine. |
2280 | Potentially transition state 'unchecked' to 'nonnull' or to 'null'. */ | |
2281 | ||
2282 | void | |
2283 | malloc_state_machine::on_condition (sm_context *sm_ctxt, | |
1690a839 | 2284 | const supernode *node ATTRIBUTE_UNUSED, |
757bf1df | 2285 | const gimple *stmt, |
48e8a7a6 | 2286 | const svalue *lhs, |
757bf1df | 2287 | enum tree_code op, |
48e8a7a6 | 2288 | const svalue *rhs) const |
757bf1df | 2289 | { |
48e8a7a6 | 2290 | if (!rhs->all_zeroes_p ()) |
757bf1df DM |
2291 | return; |
2292 | ||
2293 | if (!any_pointer_p (lhs)) | |
2294 | return; | |
2295 | if (!any_pointer_p (rhs)) | |
2296 | return; | |
2297 | ||
2298 | if (op == NE_EXPR) | |
2299 | { | |
2300 | log ("got 'ARG != 0' match"); | |
1690a839 DM |
2301 | state_t s = sm_ctxt->get_state (stmt, lhs); |
2302 | if (unchecked_p (s)) | |
2303 | { | |
2304 | const allocation_state *astate = as_a_allocation_state (s); | |
2305 | sm_ctxt->set_next_state (stmt, lhs, astate->get_nonnull ()); | |
2306 | } | |
757bf1df DM |
2307 | } |
2308 | else if (op == EQ_EXPR) | |
2309 | { | |
2310 | log ("got 'ARG == 0' match"); | |
1690a839 DM |
2311 | state_t s = sm_ctxt->get_state (stmt, lhs); |
2312 | if (unchecked_p (s)) | |
2313 | sm_ctxt->set_next_state (stmt, lhs, m_null); | |
757bf1df DM |
2314 | } |
2315 | } | |
2316 | ||
5c6546ca DM |
2317 | /* Implementation of state_machine::on_pop_frame vfunc for malloc_state_machine. |
2318 | Clear any "assumed-non-null" state where the assumption happened in | |
2319 | FRAME_REG. */ | |
2320 | ||
2321 | void | |
2322 | malloc_state_machine::on_pop_frame (sm_state_map *smap, | |
2323 | const frame_region *frame_reg) const | |
2324 | { | |
2325 | hash_set<const svalue *> svals_to_clear; | |
2326 | for (auto kv : *smap) | |
2327 | { | |
2328 | const svalue *sval = kv.first; | |
2329 | state_t state = kv.second.m_state; | |
2330 | if (assumed_non_null_p (state)) | |
2331 | { | |
2332 | const assumed_non_null_state *assumed_state | |
2333 | = (const assumed_non_null_state *)state; | |
2334 | if (frame_reg == assumed_state->m_frame) | |
2335 | svals_to_clear.add (sval); | |
2336 | } | |
2337 | } | |
2338 | for (auto sval : svals_to_clear) | |
2339 | smap->clear_any_state (sval); | |
2340 | } | |
2341 | ||
757bf1df DM |
2342 | /* Implementation of state_machine::can_purge_p vfunc for malloc_state_machine. |
2343 | Don't allow purging of pointers in state 'unchecked' or 'nonnull' | |
2344 | (to avoid false leak reports). */ | |
2345 | ||
2346 | bool | |
2347 | malloc_state_machine::can_purge_p (state_t s) const | |
2348 | { | |
1690a839 DM |
2349 | enum resource_state rs = get_rs (s); |
2350 | return rs != RS_UNCHECKED && rs != RS_NONNULL; | |
757bf1df DM |
2351 | } |
2352 | ||
2353 | /* Implementation of state_machine::on_leak vfunc for malloc_state_machine | |
2354 | (for complaining about leaks of pointers in state 'unchecked' and | |
2355 | 'nonnull'). */ | |
2356 | ||
6341f14e | 2357 | std::unique_ptr<pending_diagnostic> |
757bf1df DM |
2358 | malloc_state_machine::on_leak (tree var) const |
2359 | { | |
6341f14e | 2360 | return make_unique<malloc_leak> (*this, var); |
757bf1df DM |
2361 | } |
2362 | ||
808f4dfe DM |
2363 | /* Implementation of state_machine::reset_when_passed_to_unknown_fn_p vfunc |
2364 | for malloc_state_machine. */ | |
2365 | ||
2366 | bool | |
2367 | malloc_state_machine::reset_when_passed_to_unknown_fn_p (state_t s, | |
2368 | bool is_mutable) const | |
2369 | { | |
2370 | /* An on-stack ptr doesn't stop being stack-allocated when passed to an | |
2371 | unknown fn. */ | |
2372 | if (s == m_non_heap) | |
2373 | return false; | |
2374 | ||
2375 | /* Otherwise, pointers passed as non-const can be freed. */ | |
2376 | return is_mutable; | |
2377 | } | |
2378 | ||
5c6546ca DM |
2379 | /* Implementation of state_machine::maybe_get_merged_states_nonequal vfunc |
2380 | for malloc_state_machine. | |
2381 | ||
2382 | Support discarding "assumed-non-null" states when merging with | |
2383 | start state. */ | |
2384 | ||
2385 | state_machine::state_t | |
2386 | malloc_state_machine::maybe_get_merged_states_nonequal (state_t state_a, | |
2387 | state_t state_b) const | |
2388 | { | |
2389 | if (assumed_non_null_p (state_a) && state_b == m_start) | |
2390 | return m_start; | |
2391 | if (state_a == m_start && assumed_non_null_p (state_b)) | |
2392 | return m_start; | |
2393 | return NULL; | |
2394 | } | |
2395 | ||
cd323d97 DM |
2396 | /* Return true if calls to FNDECL are known to not affect this sm-state. */ |
2397 | ||
2398 | bool | |
2399 | malloc_state_machine::unaffected_by_call_p (tree fndecl) | |
2400 | { | |
2401 | /* A set of functions that are known to not affect allocation | |
2402 | status, even if we haven't fully modelled the rest of their | |
2403 | behavior yet. */ | |
2404 | static const char * const funcnames[] = { | |
2405 | /* This array must be kept sorted. */ | |
2406 | "strsep", | |
2407 | }; | |
ca32b29e | 2408 | const size_t count = ARRAY_SIZE (funcnames); |
cd323d97 DM |
2409 | function_set fs (funcnames, count); |
2410 | ||
2411 | if (fs.contains_decl_p (fndecl)) | |
2412 | return true; | |
2413 | ||
2414 | return false; | |
2415 | } | |
2416 | ||
8525d1f5 DM |
2417 | /* Shared logic for handling GIMPLE_ASSIGNs and GIMPLE_PHIs that |
2418 | assign zero to LHS. */ | |
2419 | ||
2420 | void | |
2421 | malloc_state_machine::on_zero_assignment (sm_context *sm_ctxt, | |
8525d1f5 DM |
2422 | const gimple *stmt, |
2423 | tree lhs) const | |
2424 | { | |
1690a839 DM |
2425 | state_t s = sm_ctxt->get_state (stmt, lhs); |
2426 | enum resource_state rs = get_rs (s); | |
2427 | if (rs == RS_START | |
2428 | || rs == RS_UNCHECKED | |
2429 | || rs == RS_NONNULL | |
2430 | || rs == RS_FREED) | |
2431 | sm_ctxt->set_next_state (stmt, lhs, m_null); | |
8525d1f5 DM |
2432 | } |
2433 | ||
eafa9d96 DM |
2434 | /* Special-case hook for handling realloc, for the "success with move to |
2435 | a new buffer" case, marking OLD_PTR_SVAL as freed and NEW_PTR_SVAL as | |
2436 | non-null. | |
2437 | ||
2438 | This is similar to on_deallocator_call and on_allocator_call, | |
2439 | but the checks happen in on_realloc_call, and by splitting the states. */ | |
2440 | ||
2441 | void | |
2442 | malloc_state_machine:: | |
2443 | on_realloc_with_move (region_model *model, | |
2444 | sm_state_map *smap, | |
2445 | const svalue *old_ptr_sval, | |
2446 | const svalue *new_ptr_sval, | |
2447 | const extrinsic_state &ext_state) const | |
2448 | { | |
2449 | smap->set_state (model, old_ptr_sval, | |
2450 | m_free.m_deallocator.m_freed, | |
2451 | NULL, ext_state); | |
2452 | ||
2453 | smap->set_state (model, new_ptr_sval, | |
2454 | m_free.m_nonnull, | |
2455 | NULL, ext_state); | |
2456 | } | |
2457 | ||
757bf1df DM |
2458 | } // anonymous namespace |
2459 | ||
2460 | /* Internal interface to this file. */ | |
2461 | ||
2462 | state_machine * | |
2463 | make_malloc_state_machine (logger *logger) | |
2464 | { | |
2465 | return new malloc_state_machine (logger); | |
2466 | } | |
2467 | ||
eafa9d96 | 2468 | /* Specialcase hook for handling realloc, for use by |
6bd31b33 | 2469 | kf_realloc::impl_call_post::success_with_move::update_model. */ |
eafa9d96 DM |
2470 | |
2471 | void | |
2472 | region_model::on_realloc_with_move (const call_details &cd, | |
2473 | const svalue *old_ptr_sval, | |
2474 | const svalue *new_ptr_sval) | |
2475 | { | |
2476 | region_model_context *ctxt = cd.get_ctxt (); | |
2477 | if (!ctxt) | |
2478 | return; | |
2479 | const extrinsic_state *ext_state = ctxt->get_ext_state (); | |
2480 | if (!ext_state) | |
2481 | return; | |
2482 | ||
2483 | sm_state_map *smap; | |
2484 | const state_machine *sm; | |
2485 | unsigned sm_idx; | |
2486 | if (!ctxt->get_malloc_map (&smap, &sm, &sm_idx)) | |
2487 | return; | |
2488 | ||
2489 | gcc_assert (smap); | |
2490 | gcc_assert (sm); | |
2491 | ||
2492 | const malloc_state_machine &malloc_sm | |
2493 | = (const malloc_state_machine &)*sm; | |
2494 | ||
2495 | malloc_sm.on_realloc_with_move (this, | |
2496 | smap, | |
2497 | old_ptr_sval, | |
2498 | new_ptr_sval, | |
2499 | *ext_state); | |
2500 | } | |
2501 | ||
75038aa6 DM |
2502 | } // namespace ana |
2503 | ||
757bf1df | 2504 | #endif /* #if ENABLE_ANALYZER */ |