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1 // Copyright (c) 2005, Google Inc. | |
2 // All rights reserved. | |
3 // | |
4 // Redistribution and use in source and binary forms, with or without | |
5 // modification, are permitted provided that the following conditions are | |
6 // met: | |
7 // | |
8 // * Redistributions of source code must retain the above copyright | |
9 // notice, this list of conditions and the following disclaimer. | |
10 // * Redistributions in binary form must reproduce the above | |
11 // copyright notice, this list of conditions and the following disclaimer | |
12 // in the documentation and/or other materials provided with the | |
13 // distribution. | |
14 // * Neither the name of Google Inc. nor the names of its | |
15 // contributors may be used to endorse or promote products derived from | |
16 // this software without specific prior written permission. | |
17 // | |
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
29 | |
30 // --- | |
31 // Author: Maxim Lifantsev (with design ideas by Sanjay Ghemawat) | |
32 // | |
33 // | |
34 // Module for detecing heap (memory) leaks. | |
35 // | |
36 // For full(er) information, see doc/heap_checker.html | |
37 // | |
38 // This module can be linked into programs with | |
39 // no slowdown caused by this unless you activate the leak-checker: | |
40 // | |
41 // 1. Set the environment variable HEAPCHEK to _type_ before | |
42 // running the program. | |
43 // | |
44 // _type_ is usually "normal" but can also be "minimal", "strict", or | |
45 // "draconian". (See the html file for other options, like 'local'.) | |
46 // | |
47 // After that, just run your binary. If the heap-checker detects | |
48 // a memory leak at program-exit, it will print instructions on how | |
49 // to track down the leak. | |
50 | |
51 #ifndef BASE_HEAP_CHECKER_H_ | |
52 #define BASE_HEAP_CHECKER_H_ | |
53 | |
54 #include <sys/types.h> // for size_t | |
55 // I can't #include config.h in this public API file, but I should | |
56 // really use configure (and make malloc_extension.h a .in file) to | |
57 // figure out if the system has stdint.h or not. But I'm lazy, so | |
58 // for now I'm assuming it's a problem only with MSVC. | |
59 #ifndef _MSC_VER | |
60 #include <stdint.h> // for uintptr_t | |
61 #endif | |
62 #include <stdarg.h> // for va_list | |
63 #include <vector> | |
64 | |
65 // Annoying stuff for windows -- makes sure clients can import these functions | |
66 #ifndef PERFTOOLS_DLL_DECL | |
67 # ifdef _WIN32 | |
68 # define PERFTOOLS_DLL_DECL __declspec(dllimport) | |
69 # else | |
70 # define PERFTOOLS_DLL_DECL | |
71 # endif | |
72 #endif | |
73 | |
74 | |
75 // The class is thread-safe with respect to all the provided static methods, | |
76 // as well as HeapLeakChecker objects: they can be accessed by multiple threads. | |
77 class PERFTOOLS_DLL_DECL HeapLeakChecker { | |
78 public: | |
79 | |
80 // ----------------------------------------------------------------------- // | |
81 // Static functions for working with (whole-program) leak checking. | |
82 | |
83 // If heap leak checking is currently active in some mode | |
84 // e.g. if leak checking was started (and is still active now) | |
85 // due to HEAPCHECK=... defined in the environment. | |
86 // The return value reflects iff HeapLeakChecker objects manually | |
87 // constructed right now will be doing leak checking or nothing. | |
88 // Note that we can go from active to inactive state during InitGoogle() | |
89 // if FLAGS_heap_check gets set to "" by some code before/during InitGoogle(). | |
90 static bool IsActive(); | |
91 | |
92 // Return pointer to the whole-program checker if it has been created | |
93 // and NULL otherwise. | |
94 // Once GlobalChecker() returns non-NULL that object will not disappear and | |
95 // will be returned by all later GlobalChecker calls. | |
96 // This is mainly to access BytesLeaked() and ObjectsLeaked() (see below) | |
97 // for the whole-program checker after one calls NoGlobalLeaks() | |
98 // or similar and gets false. | |
99 static HeapLeakChecker* GlobalChecker(); | |
100 | |
101 // Do whole-program leak check now (if it was activated for this binary); | |
102 // return false only if it was activated and has failed. | |
103 // The mode of the check is controlled by the command-line flags. | |
104 // This method can be called repeatedly. | |
105 // Things like GlobalChecker()->SameHeap() can also be called explicitly | |
106 // to do the desired flavor of the check. | |
107 static bool NoGlobalLeaks(); | |
108 | |
109 // If whole-program checker if active, | |
110 // cancel its automatic execution after main() exits. | |
111 // This requires that some leak check (e.g. NoGlobalLeaks()) | |
112 // has been called at least once on the whole-program checker. | |
113 static void CancelGlobalCheck(); | |
114 | |
115 // ----------------------------------------------------------------------- // | |
116 // Non-static functions for starting and doing leak checking. | |
117 | |
118 // Start checking and name the leak check performed. | |
119 // The name is used in naming dumped profiles | |
120 // and needs to be unique only within your binary. | |
121 // It must also be a string that can be a part of a file name, | |
122 // in particular not contain path expressions. | |
123 explicit HeapLeakChecker(const char *name); | |
124 | |
125 // Destructor (verifies that some *NoLeaks or *SameHeap method | |
126 // has been called at least once). | |
127 ~HeapLeakChecker(); | |
128 | |
129 // These used to be different but are all the same now: they return | |
130 // true iff all memory allocated since this HeapLeakChecker object | |
131 // was constructor is still reachable from global state. | |
132 // | |
133 // Because we fork to convert addresses to symbol-names, and forking | |
134 // is not thread-safe, and we may be called in a threaded context, | |
135 // we do not try to symbolize addresses when called manually. | |
136 bool NoLeaks() { return DoNoLeaks(DO_NOT_SYMBOLIZE); } | |
137 | |
138 // These forms are obsolete; use NoLeaks() instead. | |
139 // TODO(csilvers): mark as DEPRECATED. | |
140 bool QuickNoLeaks() { return NoLeaks(); } | |
141 bool BriefNoLeaks() { return NoLeaks(); } | |
142 bool SameHeap() { return NoLeaks(); } | |
143 bool QuickSameHeap() { return NoLeaks(); } | |
144 bool BriefSameHeap() { return NoLeaks(); } | |
145 | |
146 // Detailed information about the number of leaked bytes and objects | |
147 // (both of these can be negative as well). | |
148 // These are available only after a *SameHeap or *NoLeaks | |
149 // method has been called. | |
150 // Note that it's possible for both of these to be zero | |
151 // while SameHeap() or NoLeaks() returned false in case | |
152 // of a heap state change that is significant | |
153 // but preserves the byte and object counts. | |
154 ssize_t BytesLeaked() const; | |
155 ssize_t ObjectsLeaked() const; | |
156 | |
157 // ----------------------------------------------------------------------- // | |
158 // Static helpers to make us ignore certain leaks. | |
159 | |
160 // Scoped helper class. Should be allocated on the stack inside a | |
161 // block of code. Any heap allocations done in the code block | |
162 // covered by the scoped object (including in nested function calls | |
163 // done by the code block) will not be reported as leaks. This is | |
164 // the recommended replacement for the GetDisableChecksStart() and | |
165 // DisableChecksToHereFrom() routines below. | |
166 // | |
167 // Example: | |
168 // void Foo() { | |
169 // HeapLeakChecker::Disabler disabler; | |
170 // ... code that allocates objects whose leaks should be ignored ... | |
171 // } | |
172 // | |
173 // REQUIRES: Destructor runs in same thread as constructor | |
174 class Disabler { | |
175 public: | |
176 Disabler(); | |
177 ~Disabler(); | |
178 private: | |
179 Disabler(const Disabler&); // disallow copy | |
180 void operator=(const Disabler&); // and assign | |
181 }; | |
182 | |
183 // Ignore an object located at 'ptr' (can go at the start or into the object) | |
184 // as well as all heap objects (transitively) referenced from it for the | |
185 // purposes of heap leak checking. Returns 'ptr' so that one can write | |
186 // static T* obj = IgnoreObject(new T(...)); | |
187 // | |
188 // If 'ptr' does not point to an active allocated object at the time of this | |
189 // call, it is ignored; but if it does, the object must not get deleted from | |
190 // the heap later on. | |
191 // | |
192 // See also HiddenPointer, below, if you need to prevent a pointer from | |
193 // being traversed by the heap checker but do not wish to transitively | |
194 // whitelist objects referenced through it. | |
195 template <typename T> | |
196 static T* IgnoreObject(T* ptr) { | |
197 DoIgnoreObject(static_cast<const void*>(const_cast<const T*>(ptr))); | |
198 return ptr; | |
199 } | |
200 | |
201 // Undo what an earlier IgnoreObject() call promised and asked to do. | |
202 // At the time of this call 'ptr' must point at or inside of an active | |
203 // allocated object which was previously registered with IgnoreObject(). | |
204 static void UnIgnoreObject(const void* ptr); | |
205 | |
206 // ----------------------------------------------------------------------- // | |
207 // Internal types defined in .cc | |
208 | |
209 class Allocator; | |
210 struct RangeValue; | |
211 | |
212 private: | |
213 | |
214 // ----------------------------------------------------------------------- // | |
215 // Various helpers | |
216 | |
217 // Create the name of the heap profile file. | |
218 // Should be deleted via Allocator::Free(). | |
219 char* MakeProfileNameLocked(); | |
220 | |
221 // Helper for constructors | |
222 void Create(const char *name, bool make_start_snapshot); | |
223 | |
224 enum ShouldSymbolize { SYMBOLIZE, DO_NOT_SYMBOLIZE }; | |
225 | |
226 // Helper for *NoLeaks and *SameHeap | |
227 bool DoNoLeaks(ShouldSymbolize should_symbolize); | |
228 | |
229 // Helper for NoGlobalLeaks, also called by the global destructor. | |
230 static bool NoGlobalLeaksMaybeSymbolize(ShouldSymbolize should_symbolize); | |
231 | |
232 // These used to be public, but they are now deprecated. | |
233 // Will remove entirely when all internal uses are fixed. | |
234 // In the meantime, use friendship so the unittest can still test them. | |
235 static void* GetDisableChecksStart(); | |
236 static void DisableChecksToHereFrom(const void* start_address); | |
237 static void DisableChecksIn(const char* pattern); | |
238 friend void RangeDisabledLeaks(); | |
239 friend void NamedTwoDisabledLeaks(); | |
240 friend void* RunNamedDisabledLeaks(void*); | |
241 friend void TestHeapLeakCheckerNamedDisabling(); | |
242 // TODO(csilvers): remove this one, at least | |
243 friend int main(int, char**); | |
244 | |
245 | |
246 // Actually implements IgnoreObject(). | |
247 static void DoIgnoreObject(const void* ptr); | |
248 | |
249 // Disable checks based on stack trace entry at a depth <= | |
250 // max_depth. Used to hide allocations done inside some special | |
251 // libraries. | |
252 static void DisableChecksFromToLocked(const void* start_address, | |
253 const void* end_address, | |
254 int max_depth); | |
255 | |
256 // Helper for DoNoLeaks to ignore all objects reachable from all live data | |
257 static void IgnoreAllLiveObjectsLocked(const void* self_stack_top); | |
258 | |
259 // Callback we pass to ListAllProcessThreads (see thread_lister.h) | |
260 // that is invoked when all threads of our process are found and stopped. | |
261 // The call back does the things needed to ignore live data reachable from | |
262 // thread stacks and registers for all our threads | |
263 // as well as do other global-live-data ignoring | |
264 // (via IgnoreNonThreadLiveObjectsLocked) | |
265 // during the quiet state of all threads being stopped. | |
266 // For the argument meaning see the comment by ListAllProcessThreads. | |
267 // Here we only use num_threads and thread_pids, that ListAllProcessThreads | |
268 // fills for us with the number and pids of all the threads of our process | |
269 // it found and attached to. | |
270 static int IgnoreLiveThreadsLocked(void* parameter, | |
271 int num_threads, | |
272 pid_t* thread_pids, | |
273 va_list ap); | |
274 | |
275 // Helper for IgnoreAllLiveObjectsLocked and IgnoreLiveThreadsLocked | |
276 // that we prefer to execute from IgnoreLiveThreadsLocked | |
277 // while all threads are stopped. | |
278 // This helper does live object discovery and ignoring | |
279 // for all objects that are reachable from everything | |
280 // not related to thread stacks and registers. | |
281 static void IgnoreNonThreadLiveObjectsLocked(); | |
282 | |
283 // Helper for IgnoreNonThreadLiveObjectsLocked and IgnoreLiveThreadsLocked | |
284 // to discover and ignore all heap objects | |
285 // reachable from currently considered live objects | |
286 // (live_objects static global variable in out .cc file). | |
287 // "name", "name2" are two strings that we print one after another | |
288 // in a debug message to describe what kind of live object sources | |
289 // are being used. | |
290 static void IgnoreLiveObjectsLocked(const char* name, const char* name2); | |
291 | |
292 // Do the overall whole-program heap leak check if needed; | |
293 // returns true when did the leak check. | |
294 static bool DoMainHeapCheck(); | |
295 | |
296 // Type of task for UseProcMapsLocked | |
297 enum ProcMapsTask { | |
298 RECORD_GLOBAL_DATA, | |
299 DISABLE_LIBRARY_ALLOCS | |
300 }; | |
301 | |
302 // Success/Error Return codes for UseProcMapsLocked. | |
303 enum ProcMapsResult { | |
304 PROC_MAPS_USED, | |
305 CANT_OPEN_PROC_MAPS, | |
306 NO_SHARED_LIBS_IN_PROC_MAPS | |
307 }; | |
308 | |
309 // Read /proc/self/maps, parse it, and do the 'proc_maps_task' for each line. | |
310 static ProcMapsResult UseProcMapsLocked(ProcMapsTask proc_maps_task); | |
311 | |
312 // A ProcMapsTask to disable allocations from 'library' | |
313 // that is mapped to [start_address..end_address) | |
314 // (only if library is a certain system library). | |
315 static void DisableLibraryAllocsLocked(const char* library, | |
316 uintptr_t start_address, | |
317 uintptr_t end_address); | |
318 | |
319 // Return true iff "*ptr" points to a heap object | |
320 // ("*ptr" can point at the start or inside of a heap object | |
321 // so that this works e.g. for pointers to C++ arrays, C++ strings, | |
322 // multiple-inherited objects, or pointers to members). | |
323 // We also fill *object_size for this object then | |
324 // and we move "*ptr" to point to the very start of the heap object. | |
325 static inline bool HaveOnHeapLocked(const void** ptr, size_t* object_size); | |
326 | |
327 // Helper to shutdown heap leak checker when it's not needed | |
328 // or can't function properly. | |
329 static void TurnItselfOffLocked(); | |
330 | |
331 // Internally-used c-tor to start whole-executable checking. | |
332 HeapLeakChecker(); | |
333 | |
334 // ----------------------------------------------------------------------- // | |
335 // Friends and externally accessed helpers. | |
336 | |
337 // Helper for VerifyHeapProfileTableStackGet in the unittest | |
338 // to get the recorded allocation caller for ptr, | |
339 // which must be a heap object. | |
340 static const void* GetAllocCaller(void* ptr); | |
341 friend void VerifyHeapProfileTableStackGet(); | |
342 | |
343 // This gets to execute before constructors for all global objects | |
344 static void BeforeConstructorsLocked(); | |
345 friend void HeapLeakChecker_BeforeConstructors(); | |
346 | |
347 // This gets to execute after destructors for all global objects | |
348 friend void HeapLeakChecker_AfterDestructors(); | |
349 | |
350 // Full starting of recommended whole-program checking. | |
351 friend void HeapLeakChecker_InternalInitStart(); | |
352 | |
353 // Runs REGISTER_HEAPCHECK_CLEANUP cleanups and potentially | |
354 // calls DoMainHeapCheck | |
355 friend void HeapLeakChecker_RunHeapCleanups(); | |
356 | |
357 // ----------------------------------------------------------------------- // | |
358 // Member data. | |
359 | |
360 class SpinLock* lock_; // to make HeapLeakChecker objects thread-safe | |
361 const char* name_; // our remembered name (we own it) | |
362 // NULL means this leak checker is a noop | |
363 | |
364 // Snapshot taken when the checker was created. May be NULL | |
365 // for the global heap checker object. We use void* instead of | |
366 // HeapProfileTable::Snapshot* to avoid including heap-profile-table.h. | |
367 void* start_snapshot_; | |
368 | |
369 bool has_checked_; // if we have done the leak check, so these are ready: | |
370 ssize_t inuse_bytes_increase_; // bytes-in-use increase for this checker | |
371 ssize_t inuse_allocs_increase_; // allocations-in-use increase | |
372 // for this checker | |
373 bool keep_profiles_; // iff we should keep the heap profiles we've made | |
374 | |
375 // ----------------------------------------------------------------------- // | |
376 | |
377 // Disallow "evil" constructors. | |
378 HeapLeakChecker(const HeapLeakChecker&); | |
379 void operator=(const HeapLeakChecker&); | |
380 }; | |
381 | |
382 | |
383 // Holds a pointer that will not be traversed by the heap checker. | |
384 // Contrast with HeapLeakChecker::IgnoreObject(o), in which o and | |
385 // all objects reachable from o are ignored by the heap checker. | |
386 template <class T> | |
387 class HiddenPointer { | |
388 public: | |
389 explicit HiddenPointer(T* t) | |
390 : masked_t_(reinterpret_cast<uintptr_t>(t) ^ kHideMask) { | |
391 } | |
392 // Returns unhidden pointer. Be careful where you save the result. | |
393 T* get() const { return reinterpret_cast<T*>(masked_t_ ^ kHideMask); } | |
394 | |
395 private: | |
396 // Arbitrary value, but not such that xor'ing with it is likely | |
397 // to map one valid pointer to another valid pointer: | |
398 static const uintptr_t kHideMask = | |
399 static_cast<uintptr_t>(0xF03A5F7BF03A5F7Bll); | |
400 uintptr_t masked_t_; | |
401 }; | |
402 | |
403 // A class that exists solely to run its destructor. This class should not be | |
404 // used directly, but instead by the REGISTER_HEAPCHECK_CLEANUP macro below. | |
405 class PERFTOOLS_DLL_DECL HeapCleaner { | |
406 public: | |
407 typedef void (*void_function)(void); | |
408 HeapCleaner(void_function f); | |
409 static void RunHeapCleanups(); | |
410 private: | |
411 static std::vector<void_function>* heap_cleanups_; | |
412 }; | |
413 | |
414 // A macro to declare module heap check cleanup tasks | |
415 // (they run only if we are doing heap leak checking.) | |
416 // 'body' should be the cleanup code to run. 'name' doesn't matter, | |
417 // but must be unique amongst all REGISTER_HEAPCHECK_CLEANUP calls. | |
418 #define REGISTER_HEAPCHECK_CLEANUP(name, body) \ | |
419 namespace { \ | |
420 void heapcheck_cleanup_##name() { body; } \ | |
421 static HeapCleaner heapcheck_cleaner_##name(&heapcheck_cleanup_##name); \ | |
422 } | |
423 | |
424 #endif // BASE_HEAP_CHECKER_H_ | |
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