File: heap-checker.h

package info (click to toggle)
google-perftools 2.7-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 7,284 kB
  • sloc: cpp: 27,869; ansic: 9,534; sh: 4,799; perl: 4,116; makefile: 1,101; asm: 128
file content (422 lines) | stat: -rw-r--r-- 17,703 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
// Copyright (c) 2005, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// ---
// Author: Maxim Lifantsev (with design ideas by Sanjay Ghemawat)
//
//
// Module for detecing heap (memory) leaks.
//
// For full(er) information, see docs/heap_checker.html
//
// This module can be linked into programs with
// no slowdown caused by this unless you activate the leak-checker:
//
//    1. Set the environment variable HEAPCHEK to _type_ before
//       running the program.
//
// _type_ is usually "normal" but can also be "minimal", "strict", or
// "draconian".  (See the html file for other options, like 'local'.)
//
// After that, just run your binary.  If the heap-checker detects
// a memory leak at program-exit, it will print instructions on how
// to track down the leak.

#ifndef BASE_HEAP_CHECKER_H_
#define BASE_HEAP_CHECKER_H_

#include <sys/types.h>  // for size_t
// I can't #include config.h in this public API file, but I should
// really use configure (and make malloc_extension.h a .in file) to
// figure out if the system has stdint.h or not.  But I'm lazy, so
// for now I'm assuming it's a problem only with MSVC.
#ifndef _MSC_VER
#include <stdint.h>     // for uintptr_t
#endif
#include <stdarg.h>     // for va_list
#include <vector>

// Annoying stuff for windows -- makes sure clients can import these functions
#ifndef PERFTOOLS_DLL_DECL
# ifdef _WIN32
#   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
# else
#   define PERFTOOLS_DLL_DECL
# endif
#endif


// The class is thread-safe with respect to all the provided static methods,
// as well as HeapLeakChecker objects: they can be accessed by multiple threads.
class PERFTOOLS_DLL_DECL HeapLeakChecker {
 public:

  // ----------------------------------------------------------------------- //
  // Static functions for working with (whole-program) leak checking.

  // If heap leak checking is currently active in some mode
  // e.g. if leak checking was started (and is still active now)
  // due to HEAPCHECK=... defined in the environment.
  // The return value reflects iff HeapLeakChecker objects manually
  // constructed right now will be doing leak checking or nothing.
  // Note that we can go from active to inactive state during InitGoogle()
  // if FLAGS_heap_check gets set to "" by some code before/during InitGoogle().
  static bool IsActive();

  // Return pointer to the whole-program checker if it has been created
  // and NULL otherwise.
  // Once GlobalChecker() returns non-NULL that object will not disappear and
  // will be returned by all later GlobalChecker calls.
  // This is mainly to access BytesLeaked() and ObjectsLeaked() (see below)
  // for the whole-program checker after one calls NoGlobalLeaks()
  // or similar and gets false.
  static HeapLeakChecker* GlobalChecker();

  // Do whole-program leak check now (if it was activated for this binary);
  // return false only if it was activated and has failed.
  // The mode of the check is controlled by the command-line flags.
  // This method can be called repeatedly.
  // Things like GlobalChecker()->SameHeap() can also be called explicitly
  // to do the desired flavor of the check.
  static bool NoGlobalLeaks();

  // If whole-program checker if active,
  // cancel its automatic execution after main() exits.
  // This requires that some leak check (e.g. NoGlobalLeaks())
  // has been called at least once on the whole-program checker.
  static void CancelGlobalCheck();

  // ----------------------------------------------------------------------- //
  // Non-static functions for starting and doing leak checking.

  // Start checking and name the leak check performed.
  // The name is used in naming dumped profiles
  // and needs to be unique only within your binary.
  // It must also be a string that can be a part of a file name,
  // in particular not contain path expressions.
  explicit HeapLeakChecker(const char *name);

  // Destructor (verifies that some *NoLeaks or *SameHeap method
  // has been called at least once).
  ~HeapLeakChecker();

  // These used to be different but are all the same now: they return
  // true iff all memory allocated since this HeapLeakChecker object
  // was constructor is still reachable from global state.
  //
  // Because we fork to convert addresses to symbol-names, and forking
  // is not thread-safe, and we may be called in a threaded context,
  // we do not try to symbolize addresses when called manually.
  bool NoLeaks() { return DoNoLeaks(DO_NOT_SYMBOLIZE); }

  // These forms are obsolete; use NoLeaks() instead.
  // TODO(csilvers): mark as DEPRECATED.
  bool QuickNoLeaks()  { return NoLeaks(); }
  bool BriefNoLeaks()  { return NoLeaks(); }
  bool SameHeap()      { return NoLeaks(); }
  bool QuickSameHeap() { return NoLeaks(); }
  bool BriefSameHeap() { return NoLeaks(); }

  // Detailed information about the number of leaked bytes and objects
  // (both of these can be negative as well).
  // These are available only after a *SameHeap or *NoLeaks
  // method has been called.
  // Note that it's possible for both of these to be zero
  // while SameHeap() or NoLeaks() returned false in case
  // of a heap state change that is significant
  // but preserves the byte and object counts.
  ssize_t BytesLeaked() const;
  ssize_t ObjectsLeaked() const;

  // ----------------------------------------------------------------------- //
  // Static helpers to make us ignore certain leaks.

  // Scoped helper class.  Should be allocated on the stack inside a
  // block of code.  Any heap allocations done in the code block
  // covered by the scoped object (including in nested function calls
  // done by the code block) will not be reported as leaks.  This is
  // the recommended replacement for the GetDisableChecksStart() and
  // DisableChecksToHereFrom() routines below.
  //
  // Example:
  //   void Foo() {
  //     HeapLeakChecker::Disabler disabler;
  //     ... code that allocates objects whose leaks should be ignored ...
  //   }
  //
  // REQUIRES: Destructor runs in same thread as constructor
  class Disabler {
   public:
    Disabler();
    ~Disabler();
   private:
    Disabler(const Disabler&);        // disallow copy
    void operator=(const Disabler&);  // and assign
  };

  // Ignore an object located at 'ptr' (can go at the start or into the object)
  // as well as all heap objects (transitively) referenced from it for the
  // purposes of heap leak checking. Returns 'ptr' so that one can write
  //   static T* obj = IgnoreObject(new T(...));
  //
  // If 'ptr' does not point to an active allocated object at the time of this
  // call, it is ignored; but if it does, the object must not get deleted from
  // the heap later on.
  //
  // See also HiddenPointer, below, if you need to prevent a pointer from
  // being traversed by the heap checker but do not wish to transitively
  // whitelist objects referenced through it.
  template <typename T>
  static T* IgnoreObject(T* ptr) {
    DoIgnoreObject(static_cast<const void*>(const_cast<const T*>(ptr)));
    return ptr;
  }

  // Undo what an earlier IgnoreObject() call promised and asked to do.
  // At the time of this call 'ptr' must point at or inside of an active
  // allocated object which was previously registered with IgnoreObject().
  static void UnIgnoreObject(const void* ptr);

  // ----------------------------------------------------------------------- //
  // Internal types defined in .cc

  class Allocator;
  struct RangeValue;

 private:

  // ----------------------------------------------------------------------- //
  // Various helpers

  // Create the name of the heap profile file.
  // Should be deleted via Allocator::Free().
  char* MakeProfileNameLocked();

  // Helper for constructors
  void Create(const char *name, bool make_start_snapshot);

  enum ShouldSymbolize { SYMBOLIZE, DO_NOT_SYMBOLIZE };

  // Helper for *NoLeaks and *SameHeap
  bool DoNoLeaks(ShouldSymbolize should_symbolize);

  // Helper for NoGlobalLeaks, also called by the global destructor.
  static bool NoGlobalLeaksMaybeSymbolize(ShouldSymbolize should_symbolize);

  // These used to be public, but they are now deprecated.
  // Will remove entirely when all internal uses are fixed.
  // In the meantime, use friendship so the unittest can still test them.
  static void* GetDisableChecksStart();
  static void DisableChecksToHereFrom(const void* start_address);
  static void DisableChecksIn(const char* pattern);
  friend void RangeDisabledLeaks();
  friend void NamedTwoDisabledLeaks();
  friend void* RunNamedDisabledLeaks(void*);
  friend void TestHeapLeakCheckerNamedDisabling();

  // Actually implements IgnoreObject().
  static void DoIgnoreObject(const void* ptr);

  // Disable checks based on stack trace entry at a depth <=
  // max_depth.  Used to hide allocations done inside some special
  // libraries.
  static void DisableChecksFromToLocked(const void* start_address,
                                        const void* end_address,
                                        int max_depth);

  // Helper for DoNoLeaks to ignore all objects reachable from all live data
  static void IgnoreAllLiveObjectsLocked(const void* self_stack_top);

  // Callback we pass to TCMalloc_ListAllProcessThreads (see thread_lister.h)
  // that is invoked when all threads of our process are found and stopped.
  // The call back does the things needed to ignore live data reachable from
  // thread stacks and registers for all our threads
  // as well as do other global-live-data ignoring
  // (via IgnoreNonThreadLiveObjectsLocked)
  // during the quiet state of all threads being stopped.
  // For the argument meaning see the comment by TCMalloc_ListAllProcessThreads.
  // Here we only use num_threads and thread_pids, that TCMalloc_ListAllProcessThreads
  // fills for us with the number and pids of all the threads of our process
  // it found and attached to.
  static int IgnoreLiveThreadsLocked(void* parameter,
                                     int num_threads,
                                     pid_t* thread_pids,
                                     va_list ap);

  // Helper for IgnoreAllLiveObjectsLocked and IgnoreLiveThreadsLocked
  // that we prefer to execute from IgnoreLiveThreadsLocked
  // while all threads are stopped.
  // This helper does live object discovery and ignoring
  // for all objects that are reachable from everything
  // not related to thread stacks and registers.
  static void IgnoreNonThreadLiveObjectsLocked();

  // Helper for IgnoreNonThreadLiveObjectsLocked and IgnoreLiveThreadsLocked
  // to discover and ignore all heap objects
  // reachable from currently considered live objects
  // (live_objects static global variable in out .cc file).
  // "name", "name2" are two strings that we print one after another
  // in a debug message to describe what kind of live object sources
  // are being used.
  static void IgnoreLiveObjectsLocked(const char* name, const char* name2);

  // Do the overall whole-program heap leak check if needed;
  // returns true when did the leak check.
  static bool DoMainHeapCheck();

  // Type of task for UseProcMapsLocked
  enum ProcMapsTask {
    RECORD_GLOBAL_DATA,
    DISABLE_LIBRARY_ALLOCS
  };

  // Success/Error Return codes for UseProcMapsLocked.
  enum ProcMapsResult {
    PROC_MAPS_USED,
    CANT_OPEN_PROC_MAPS,
    NO_SHARED_LIBS_IN_PROC_MAPS
  };

  // Read /proc/self/maps, parse it, and do the 'proc_maps_task' for each line.
  static ProcMapsResult UseProcMapsLocked(ProcMapsTask proc_maps_task);

  // A ProcMapsTask to disable allocations from 'library'
  // that is mapped to [start_address..end_address)
  // (only if library is a certain system library).
  static void DisableLibraryAllocsLocked(const char* library,
                                         uintptr_t start_address,
                                         uintptr_t end_address);

  // Return true iff "*ptr" points to a heap object
  // ("*ptr" can point at the start or inside of a heap object
  //  so that this works e.g. for pointers to C++ arrays, C++ strings,
  //  multiple-inherited objects, or pointers to members).
  // We also fill *object_size for this object then
  // and we move "*ptr" to point to the very start of the heap object.
  static inline bool HaveOnHeapLocked(const void** ptr, size_t* object_size);

  // Helper to shutdown heap leak checker when it's not needed
  // or can't function properly.
  static void TurnItselfOffLocked();

  // Internally-used c-tor to start whole-executable checking.
  HeapLeakChecker();

  // ----------------------------------------------------------------------- //
  // Friends and externally accessed helpers.

  // Helper for VerifyHeapProfileTableStackGet in the unittest
  // to get the recorded allocation caller for ptr,
  // which must be a heap object.
  static const void* GetAllocCaller(void* ptr);
  friend void VerifyHeapProfileTableStackGet();

  // This gets to execute before constructors for all global objects
  static void BeforeConstructorsLocked();
  friend void HeapLeakChecker_BeforeConstructors();

  // This gets to execute after destructors for all global objects
  friend void HeapLeakChecker_AfterDestructors();

  // Full starting of recommended whole-program checking.
  friend void HeapLeakChecker_InternalInitStart();

  // Runs REGISTER_HEAPCHECK_CLEANUP cleanups and potentially
  // calls DoMainHeapCheck
  friend void HeapLeakChecker_RunHeapCleanups();

  // ----------------------------------------------------------------------- //
  // Member data.

  class SpinLock* lock_;  // to make HeapLeakChecker objects thread-safe
  const char* name_;  // our remembered name (we own it)
                      // NULL means this leak checker is a noop

  // Snapshot taken when the checker was created.  May be NULL
  // for the global heap checker object.  We use void* instead of
  // HeapProfileTable::Snapshot* to avoid including heap-profile-table.h.
  void* start_snapshot_;

  bool has_checked_;  // if we have done the leak check, so these are ready:
  ssize_t inuse_bytes_increase_;  // bytes-in-use increase for this checker
  ssize_t inuse_allocs_increase_;  // allocations-in-use increase
                                   // for this checker
  bool keep_profiles_;  // iff we should keep the heap profiles we've made

  // ----------------------------------------------------------------------- //

  // Disallow "evil" constructors.
  HeapLeakChecker(const HeapLeakChecker&);
  void operator=(const HeapLeakChecker&);
};


// Holds a pointer that will not be traversed by the heap checker.
// Contrast with HeapLeakChecker::IgnoreObject(o), in which o and
// all objects reachable from o are ignored by the heap checker.
template <class T>
class HiddenPointer {
 public:
  explicit HiddenPointer(T* t)
      : masked_t_(reinterpret_cast<uintptr_t>(t) ^ kHideMask) {
  }
  // Returns unhidden pointer.  Be careful where you save the result.
  T* get() const { return reinterpret_cast<T*>(masked_t_ ^ kHideMask); }

 private:
  // Arbitrary value, but not such that xor'ing with it is likely
  // to map one valid pointer to another valid pointer:
  static const uintptr_t kHideMask =
      static_cast<uintptr_t>(0xF03A5F7BF03A5F7Bll);
  uintptr_t masked_t_;
};

// A class that exists solely to run its destructor.  This class should not be
// used directly, but instead by the REGISTER_HEAPCHECK_CLEANUP macro below.
class PERFTOOLS_DLL_DECL HeapCleaner {
 public:
  typedef void (*void_function)(void);
  HeapCleaner(void_function f);
  static void RunHeapCleanups();
 private:
  static std::vector<void_function>* heap_cleanups_;
};

// A macro to declare module heap check cleanup tasks
// (they run only if we are doing heap leak checking.)
// 'body' should be the cleanup code to run.  'name' doesn't matter,
// but must be unique amongst all REGISTER_HEAPCHECK_CLEANUP calls.
#define REGISTER_HEAPCHECK_CLEANUP(name, body)  \
  namespace { \
  void heapcheck_cleanup_##name() { body; } \
  static HeapCleaner heapcheck_cleaner_##name(&heapcheck_cleanup_##name); \
  }

#endif  // BASE_HEAP_CHECKER_H_