aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.9/libsanitizer/tsan/tsan_rtl.cc
blob: 573eeb8a9188c347b1b320d1a98457b9f87ea811 (plain)
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
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
//===-- tsan_rtl.cc -------------------------------------------------------===//
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
// Main file (entry points) for the TSan run-time.
//===----------------------------------------------------------------------===//

#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_stackdepot.h"
#include "sanitizer_common/sanitizer_placement_new.h"
#include "sanitizer_common/sanitizer_symbolizer.h"
#include "tsan_defs.h"
#include "tsan_platform.h"
#include "tsan_rtl.h"
#include "tsan_mman.h"
#include "tsan_suppressions.h"
#include "tsan_symbolize.h"

volatile int __tsan_resumed = 0;

extern "C" void __tsan_resume() {
  __tsan_resumed = 1;
}

namespace __tsan {

#ifndef TSAN_GO
THREADLOCAL char cur_thread_placeholder[sizeof(ThreadState)] ALIGNED(64);
#endif
static char ctx_placeholder[sizeof(Context)] ALIGNED(64);

// Can be overriden by a front-end.
#ifdef TSAN_EXTERNAL_HOOKS
bool OnFinalize(bool failed);
#else
SANITIZER_INTERFACE_ATTRIBUTE
bool WEAK OnFinalize(bool failed) {
  return failed;
}
#endif

static Context *ctx;
Context *CTX() {
  return ctx;
}

static char thread_registry_placeholder[sizeof(ThreadRegistry)];

static ThreadContextBase *CreateThreadContext(u32 tid) {
  // Map thread trace when context is created.
  MapThreadTrace(GetThreadTrace(tid), TraceSize() * sizeof(Event));
  MapThreadTrace(GetThreadTraceHeader(tid), sizeof(Trace));
  new(ThreadTrace(tid)) Trace();
  void *mem = internal_alloc(MBlockThreadContex, sizeof(ThreadContext));
  return new(mem) ThreadContext(tid);
}

#ifndef TSAN_GO
static const u32 kThreadQuarantineSize = 16;
#else
static const u32 kThreadQuarantineSize = 64;
#endif

Context::Context()
  : initialized()
  , report_mtx(MutexTypeReport, StatMtxReport)
  , nreported()
  , nmissed_expected()
  , thread_registry(new(thread_registry_placeholder) ThreadRegistry(
      CreateThreadContext, kMaxTid, kThreadQuarantineSize))
  , racy_stacks(MBlockRacyStacks)
  , racy_addresses(MBlockRacyAddresses)
  , fired_suppressions(8) {
}

// The objects are allocated in TLS, so one may rely on zero-initialization.
ThreadState::ThreadState(Context *ctx, int tid, int unique_id, u64 epoch,
                         uptr stk_addr, uptr stk_size,
                         uptr tls_addr, uptr tls_size)
  : fast_state(tid, epoch)
  // Do not touch these, rely on zero initialization,
  // they may be accessed before the ctor.
  // , ignore_reads_and_writes()
  // , in_rtl()
#ifndef TSAN_GO
  , jmp_bufs(MBlockJmpBuf)
#endif
  , tid(tid)
  , unique_id(unique_id)
  , stk_addr(stk_addr)
  , stk_size(stk_size)
  , tls_addr(tls_addr)
  , tls_size(tls_size) {
}

static void MemoryProfiler(Context *ctx, fd_t fd, int i) {
  uptr n_threads;
  uptr n_running_threads;
  ctx->thread_registry->GetNumberOfThreads(&n_threads, &n_running_threads);
  InternalScopedBuffer<char> buf(4096);
  internal_snprintf(buf.data(), buf.size(), "%d: nthr=%d nlive=%d\n",
      i, n_threads, n_running_threads);
  internal_write(fd, buf.data(), internal_strlen(buf.data()));
  WriteMemoryProfile(buf.data(), buf.size());
  internal_write(fd, buf.data(), internal_strlen(buf.data()));
}

static void BackgroundThread(void *arg) {
  ScopedInRtl in_rtl;
  Context *ctx = CTX();
  const u64 kMs2Ns = 1000 * 1000;

  fd_t mprof_fd = kInvalidFd;
  if (flags()->profile_memory && flags()->profile_memory[0]) {
    InternalScopedBuffer<char> filename(4096);
    internal_snprintf(filename.data(), filename.size(), "%s.%d",
        flags()->profile_memory, (int)internal_getpid());
    uptr openrv = OpenFile(filename.data(), true);
    if (internal_iserror(openrv)) {
      Printf("ThreadSanitizer: failed to open memory profile file '%s'\n",
          &filename[0]);
    } else {
      mprof_fd = openrv;
    }
  }

  u64 last_flush = NanoTime();
  uptr last_rss = 0;
  for (int i = 0; ; i++) {
    SleepForSeconds(1);
    u64 now = NanoTime();

    // Flush memory if requested.
    if (flags()->flush_memory_ms > 0) {
      if (last_flush + flags()->flush_memory_ms * kMs2Ns < now) {
        if (flags()->verbosity > 0)
          Printf("ThreadSanitizer: periodic memory flush\n");
        FlushShadowMemory();
        last_flush = NanoTime();
      }
    }
    if (flags()->memory_limit_mb > 0) {
      uptr rss = GetRSS();
      uptr limit = uptr(flags()->memory_limit_mb) << 20;
      if (flags()->verbosity > 0) {
        Printf("ThreadSanitizer: memory flush check"
               " RSS=%llu LAST=%llu LIMIT=%llu\n",
               (u64)rss>>20, (u64)last_rss>>20, (u64)limit>>20);
      }
      if (2 * rss > limit + last_rss) {
        if (flags()->verbosity > 0)
          Printf("ThreadSanitizer: flushing memory due to RSS\n");
        FlushShadowMemory();
        rss = GetRSS();
        if (flags()->verbosity > 0)
          Printf("ThreadSanitizer: memory flushed RSS=%llu\n", (u64)rss>>20);
      }
      last_rss = rss;
    }

    // Write memory profile if requested.
    if (mprof_fd != kInvalidFd)
      MemoryProfiler(ctx, mprof_fd, i);

#ifndef TSAN_GO
    // Flush symbolizer cache if requested.
    if (flags()->flush_symbolizer_ms > 0) {
      u64 last = atomic_load(&ctx->last_symbolize_time_ns,
                             memory_order_relaxed);
      if (last != 0 && last + flags()->flush_symbolizer_ms * kMs2Ns < now) {
        Lock l(&ctx->report_mtx);
        SpinMutexLock l2(&CommonSanitizerReportMutex);
        SymbolizeFlush();
        atomic_store(&ctx->last_symbolize_time_ns, 0, memory_order_relaxed);
      }
    }
#endif
  }
}

void DontNeedShadowFor(uptr addr, uptr size) {
  uptr shadow_beg = MemToShadow(addr);
  uptr shadow_end = MemToShadow(addr + size);
  FlushUnneededShadowMemory(shadow_beg, shadow_end - shadow_beg);
}

void MapShadow(uptr addr, uptr size) {
  MmapFixedNoReserve(MemToShadow(addr), size * kShadowMultiplier);
}

void MapThreadTrace(uptr addr, uptr size) {
  DPrintf("#0: Mapping trace at %p-%p(0x%zx)\n", addr, addr + size, size);
  CHECK_GE(addr, kTraceMemBegin);
  CHECK_LE(addr + size, kTraceMemBegin + kTraceMemSize);
  uptr addr1 = (uptr)MmapFixedNoReserve(addr, size);
  if (addr1 != addr) {
    Printf("FATAL: ThreadSanitizer can not mmap thread trace (%p/%p->%p)\n",
        addr, size, addr1);
    Die();
  }
}

void Initialize(ThreadState *thr) {
  // Thread safe because done before all threads exist.
  static bool is_initialized = false;
  if (is_initialized)
    return;
  is_initialized = true;
  SanitizerToolName = "ThreadSanitizer";
  // Install tool-specific callbacks in sanitizer_common.
  SetCheckFailedCallback(TsanCheckFailed);

  ScopedInRtl in_rtl;
#ifndef TSAN_GO
  InitializeAllocator();
#endif
  InitializeInterceptors();
  const char *env = InitializePlatform();
  InitializeMutex();
  InitializeDynamicAnnotations();
  ctx = new(ctx_placeholder) Context;
#ifndef TSAN_GO
  InitializeShadowMemory();
#endif
  InitializeFlags(&ctx->flags, env);
  // Setup correct file descriptor for error reports.
  __sanitizer_set_report_path(flags()->log_path);
  InitializeSuppressions();
#ifndef TSAN_GO
  InitializeLibIgnore();
  // Initialize external symbolizer before internal threads are started.
  const char *external_symbolizer = flags()->external_symbolizer_path;
  bool external_symbolizer_started =
      Symbolizer::Init(external_symbolizer)->IsExternalAvailable();
  if (external_symbolizer != 0 && external_symbolizer[0] != '\0' &&
      !external_symbolizer_started) {
    Printf("Failed to start external symbolizer: '%s'\n",
           external_symbolizer);
    Die();
  }
  Symbolizer::Get()->AddHooks(EnterSymbolizer, ExitSymbolizer);
#endif
  internal_start_thread(&BackgroundThread, 0);

  if (ctx->flags.verbosity)
    Printf("***** Running under ThreadSanitizer v2 (pid %d) *****\n",
           (int)internal_getpid());

  // Initialize thread 0.
  int tid = ThreadCreate(thr, 0, 0, true);
  CHECK_EQ(tid, 0);
  ThreadStart(thr, tid, internal_getpid());
  CHECK_EQ(thr->in_rtl, 1);
  ctx->initialized = true;

  if (flags()->stop_on_start) {
    Printf("ThreadSanitizer is suspended at startup (pid %d)."
           " Call __tsan_resume().\n",
           (int)internal_getpid());
    while (__tsan_resumed == 0) {}
  }
}

int Finalize(ThreadState *thr) {
  ScopedInRtl in_rtl;
  Context *ctx = __tsan::ctx;
  bool failed = false;

  if (flags()->atexit_sleep_ms > 0 && ThreadCount(thr) > 1)
    SleepForMillis(flags()->atexit_sleep_ms);

  // Wait for pending reports.
  ctx->report_mtx.Lock();
  CommonSanitizerReportMutex.Lock();
  CommonSanitizerReportMutex.Unlock();
  ctx->report_mtx.Unlock();

#ifndef TSAN_GO
  if (ctx->flags.verbosity)
    AllocatorPrintStats();
#endif

  ThreadFinalize(thr);

  if (ctx->nreported) {
    failed = true;
#ifndef TSAN_GO
    Printf("ThreadSanitizer: reported %d warnings\n", ctx->nreported);
#else
    Printf("Found %d data race(s)\n", ctx->nreported);
#endif
  }

  if (ctx->nmissed_expected) {
    failed = true;
    Printf("ThreadSanitizer: missed %d expected races\n",
        ctx->nmissed_expected);
  }

  if (flags()->print_suppressions)
    PrintMatchedSuppressions();
#ifndef TSAN_GO
  if (flags()->print_benign)
    PrintMatchedBenignRaces();
#endif

  failed = OnFinalize(failed);

  StatAggregate(ctx->stat, thr->stat);
  StatOutput(ctx->stat);
  return failed ? flags()->exitcode : 0;
}

#ifndef TSAN_GO
u32 CurrentStackId(ThreadState *thr, uptr pc) {
  if (thr->shadow_stack_pos == 0)  // May happen during bootstrap.
    return 0;
  if (pc) {
    thr->shadow_stack_pos[0] = pc;
    thr->shadow_stack_pos++;
  }
  u32 id = StackDepotPut(thr->shadow_stack,
                         thr->shadow_stack_pos - thr->shadow_stack);
  if (pc)
    thr->shadow_stack_pos--;
  return id;
}
#endif

void TraceSwitch(ThreadState *thr) {
  thr->nomalloc++;
  ScopedInRtl in_rtl;
  Trace *thr_trace = ThreadTrace(thr->tid);
  Lock l(&thr_trace->mtx);
  unsigned trace = (thr->fast_state.epoch() / kTracePartSize) % TraceParts();
  TraceHeader *hdr = &thr_trace->headers[trace];
  hdr->epoch0 = thr->fast_state.epoch();
  hdr->stack0.ObtainCurrent(thr, 0);
  hdr->mset0 = thr->mset;
  thr->nomalloc--;
}

Trace *ThreadTrace(int tid) {
  return (Trace*)GetThreadTraceHeader(tid);
}

uptr TraceTopPC(ThreadState *thr) {
  Event *events = (Event*)GetThreadTrace(thr->tid);
  uptr pc = events[thr->fast_state.GetTracePos()];
  return pc;
}

uptr TraceSize() {
  return (uptr)(1ull << (kTracePartSizeBits + flags()->history_size + 1));
}

uptr TraceParts() {
  return TraceSize() / kTracePartSize;
}

#ifndef TSAN_GO
extern "C" void __tsan_trace_switch() {
  TraceSwitch(cur_thread());
}

extern "C" void __tsan_report_race() {
  ReportRace(cur_thread());
}
#endif

ALWAYS_INLINE
Shadow LoadShadow(u64 *p) {
  u64 raw = atomic_load((atomic_uint64_t*)p, memory_order_relaxed);
  return Shadow(raw);
}

ALWAYS_INLINE
void StoreShadow(u64 *sp, u64 s) {
  atomic_store((atomic_uint64_t*)sp, s, memory_order_relaxed);
}

ALWAYS_INLINE
void StoreIfNotYetStored(u64 *sp, u64 *s) {
  StoreShadow(sp, *s);
  *s = 0;
}

static inline void HandleRace(ThreadState *thr, u64 *shadow_mem,
                              Shadow cur, Shadow old) {
  thr->racy_state[0] = cur.raw();
  thr->racy_state[1] = old.raw();
  thr->racy_shadow_addr = shadow_mem;
#ifndef TSAN_GO
  HACKY_CALL(__tsan_report_race);
#else
  ReportRace(thr);
#endif
}

static inline bool OldIsInSameSynchEpoch(Shadow old, ThreadState *thr) {
  return old.epoch() >= thr->fast_synch_epoch;
}

static inline bool HappensBefore(Shadow old, ThreadState *thr) {
  return thr->clock.get(old.TidWithIgnore()) >= old.epoch();
}

ALWAYS_INLINE USED
void MemoryAccessImpl(ThreadState *thr, uptr addr,
    int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic,
    u64 *shadow_mem, Shadow cur) {
  StatInc(thr, StatMop);
  StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
  StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));

  // This potentially can live in an MMX/SSE scratch register.
  // The required intrinsics are:
  // __m128i _mm_move_epi64(__m128i*);
  // _mm_storel_epi64(u64*, __m128i);
  u64 store_word = cur.raw();

  // scan all the shadow values and dispatch to 4 categories:
  // same, replace, candidate and race (see comments below).
  // we consider only 3 cases regarding access sizes:
  // equal, intersect and not intersect. initially I considered
  // larger and smaller as well, it allowed to replace some
  // 'candidates' with 'same' or 'replace', but I think
  // it's just not worth it (performance- and complexity-wise).

  Shadow old(0);
  if (kShadowCnt == 1) {
    int idx = 0;
#include "tsan_update_shadow_word_inl.h"
  } else if (kShadowCnt == 2) {
    int idx = 0;
#include "tsan_update_shadow_word_inl.h"
    idx = 1;
#include "tsan_update_shadow_word_inl.h"
  } else if (kShadowCnt == 4) {
    int idx = 0;
#include "tsan_update_shadow_word_inl.h"
    idx = 1;
#include "tsan_update_shadow_word_inl.h"
    idx = 2;
#include "tsan_update_shadow_word_inl.h"
    idx = 3;
#include "tsan_update_shadow_word_inl.h"
  } else if (kShadowCnt == 8) {
    int idx = 0;
#include "tsan_update_shadow_word_inl.h"
    idx = 1;
#include "tsan_update_shadow_word_inl.h"
    idx = 2;
#include "tsan_update_shadow_word_inl.h"
    idx = 3;
#include "tsan_update_shadow_word_inl.h"
    idx = 4;
#include "tsan_update_shadow_word_inl.h"
    idx = 5;
#include "tsan_update_shadow_word_inl.h"
    idx = 6;
#include "tsan_update_shadow_word_inl.h"
    idx = 7;
#include "tsan_update_shadow_word_inl.h"
  } else {
    CHECK(false);
  }

  // we did not find any races and had already stored
  // the current access info, so we are done
  if (LIKELY(store_word == 0))
    return;
  // choose a random candidate slot and replace it
  StoreShadow(shadow_mem + (cur.epoch() % kShadowCnt), store_word);
  StatInc(thr, StatShadowReplace);
  return;
 RACE:
  HandleRace(thr, shadow_mem, cur, old);
  return;
}

void UnalignedMemoryAccess(ThreadState *thr, uptr pc, uptr addr,
    int size, bool kAccessIsWrite, bool kIsAtomic) {
  while (size) {
    int size1 = 1;
    int kAccessSizeLog = kSizeLog1;
    if (size >= 8 && (addr & ~7) == ((addr + 8) & ~7)) {
      size1 = 8;
      kAccessSizeLog = kSizeLog8;
    } else if (size >= 4 && (addr & ~7) == ((addr + 4) & ~7)) {
      size1 = 4;
      kAccessSizeLog = kSizeLog4;
    } else if (size >= 2 && (addr & ~7) == ((addr + 2) & ~7)) {
      size1 = 2;
      kAccessSizeLog = kSizeLog2;
    }
    MemoryAccess(thr, pc, addr, kAccessSizeLog, kAccessIsWrite, kIsAtomic);
    addr += size1;
    size -= size1;
  }
}

ALWAYS_INLINE USED
void MemoryAccess(ThreadState *thr, uptr pc, uptr addr,
    int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic) {
  u64 *shadow_mem = (u64*)MemToShadow(addr);
  DPrintf2("#%d: MemoryAccess: @%p %p size=%d"
      " is_write=%d shadow_mem=%p {%zx, %zx, %zx, %zx}\n",
      (int)thr->fast_state.tid(), (void*)pc, (void*)addr,
      (int)(1 << kAccessSizeLog), kAccessIsWrite, shadow_mem,
      (uptr)shadow_mem[0], (uptr)shadow_mem[1],
      (uptr)shadow_mem[2], (uptr)shadow_mem[3]);
#if TSAN_DEBUG
  if (!IsAppMem(addr)) {
    Printf("Access to non app mem %zx\n", addr);
    DCHECK(IsAppMem(addr));
  }
  if (!IsShadowMem((uptr)shadow_mem)) {
    Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
    DCHECK(IsShadowMem((uptr)shadow_mem));
  }
#endif

  if (*shadow_mem == kShadowRodata) {
    // Access to .rodata section, no races here.
    // Measurements show that it can be 10-20% of all memory accesses.
    StatInc(thr, StatMop);
    StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    StatInc(thr, StatMopRodata);
    return;
  }

  FastState fast_state = thr->fast_state;
  if (fast_state.GetIgnoreBit())
    return;
  fast_state.IncrementEpoch();
  thr->fast_state = fast_state;
  Shadow cur(fast_state);
  cur.SetAddr0AndSizeLog(addr & 7, kAccessSizeLog);
  cur.SetWrite(kAccessIsWrite);
  cur.SetAtomic(kIsAtomic);

  // We must not store to the trace if we do not store to the shadow.
  // That is, this call must be moved somewhere below.
  TraceAddEvent(thr, fast_state, EventTypeMop, pc);

  MemoryAccessImpl(thr, addr, kAccessSizeLog, kAccessIsWrite, kIsAtomic,
      shadow_mem, cur);
}

static void MemoryRangeSet(ThreadState *thr, uptr pc, uptr addr, uptr size,
                           u64 val) {
  (void)thr;
  (void)pc;
  if (size == 0)
    return;
  // FIXME: fix me.
  uptr offset = addr % kShadowCell;
  if (offset) {
    offset = kShadowCell - offset;
    if (size <= offset)
      return;
    addr += offset;
    size -= offset;
  }
  DCHECK_EQ(addr % 8, 0);
  // If a user passes some insane arguments (memset(0)),
  // let it just crash as usual.
  if (!IsAppMem(addr) || !IsAppMem(addr + size - 1))
    return;
  // Don't want to touch lots of shadow memory.
  // If a program maps 10MB stack, there is no need reset the whole range.
  size = (size + (kShadowCell - 1)) & ~(kShadowCell - 1);
  // UnmapOrDie/MmapFixedNoReserve does not work on Windows,
  // so we do it only for C/C++.
  if (kGoMode || size < 64*1024) {
    u64 *p = (u64*)MemToShadow(addr);
    CHECK(IsShadowMem((uptr)p));
    CHECK(IsShadowMem((uptr)(p + size * kShadowCnt / kShadowCell - 1)));
    // FIXME: may overwrite a part outside the region
    for (uptr i = 0; i < size / kShadowCell * kShadowCnt;) {
      p[i++] = val;
      for (uptr j = 1; j < kShadowCnt; j++)
        p[i++] = 0;
    }
  } else {
    // The region is big, reset only beginning and end.
    const uptr kPageSize = 4096;
    u64 *begin = (u64*)MemToShadow(addr);
    u64 *end = begin + size / kShadowCell * kShadowCnt;
    u64 *p = begin;
    // Set at least first kPageSize/2 to page boundary.
    while ((p < begin + kPageSize / kShadowSize / 2) || ((uptr)p % kPageSize)) {
      *p++ = val;
      for (uptr j = 1; j < kShadowCnt; j++)
        *p++ = 0;
    }
    // Reset middle part.
    u64 *p1 = p;
    p = RoundDown(end, kPageSize);
    UnmapOrDie((void*)p1, (uptr)p - (uptr)p1);
    MmapFixedNoReserve((uptr)p1, (uptr)p - (uptr)p1);
    // Set the ending.
    while (p < end) {
      *p++ = val;
      for (uptr j = 1; j < kShadowCnt; j++)
        *p++ = 0;
    }
  }
}

void MemoryResetRange(ThreadState *thr, uptr pc, uptr addr, uptr size) {
  MemoryRangeSet(thr, pc, addr, size, 0);
}

void MemoryRangeFreed(ThreadState *thr, uptr pc, uptr addr, uptr size) {
  // Processing more than 1k (4k of shadow) is expensive,
  // can cause excessive memory consumption (user does not necessary touch
  // the whole range) and most likely unnecessary.
  if (size > 1024)
    size = 1024;
  CHECK_EQ(thr->is_freeing, false);
  thr->is_freeing = true;
  MemoryAccessRange(thr, pc, addr, size, true);
  thr->is_freeing = false;
  thr->fast_state.IncrementEpoch();
  TraceAddEvent(thr, thr->fast_state, EventTypeMop, pc);
  Shadow s(thr->fast_state);
  s.ClearIgnoreBit();
  s.MarkAsFreed();
  s.SetWrite(true);
  s.SetAddr0AndSizeLog(0, 3);
  MemoryRangeSet(thr, pc, addr, size, s.raw());
}

void MemoryRangeImitateWrite(ThreadState *thr, uptr pc, uptr addr, uptr size) {
  thr->fast_state.IncrementEpoch();
  TraceAddEvent(thr, thr->fast_state, EventTypeMop, pc);
  Shadow s(thr->fast_state);
  s.ClearIgnoreBit();
  s.SetWrite(true);
  s.SetAddr0AndSizeLog(0, 3);
  MemoryRangeSet(thr, pc, addr, size, s.raw());
}

ALWAYS_INLINE USED
void FuncEntry(ThreadState *thr, uptr pc) {
  DCHECK_EQ(thr->in_rtl, 0);
  StatInc(thr, StatFuncEnter);
  DPrintf2("#%d: FuncEntry %p\n", (int)thr->fast_state.tid(), (void*)pc);
  thr->fast_state.IncrementEpoch();
  TraceAddEvent(thr, thr->fast_state, EventTypeFuncEnter, pc);

  // Shadow stack maintenance can be replaced with
  // stack unwinding during trace switch (which presumably must be faster).
  DCHECK_GE(thr->shadow_stack_pos, thr->shadow_stack);
#ifndef TSAN_GO
  DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
#else
  if (thr->shadow_stack_pos == thr->shadow_stack_end) {
    const int sz = thr->shadow_stack_end - thr->shadow_stack;
    const int newsz = 2 * sz;
    uptr *newstack = (uptr*)internal_alloc(MBlockShadowStack,
        newsz * sizeof(uptr));
    internal_memcpy(newstack, thr->shadow_stack, sz * sizeof(uptr));
    internal_free(thr->shadow_stack);
    thr->shadow_stack = newstack;
    thr->shadow_stack_pos = newstack + sz;
    thr->shadow_stack_end = newstack + newsz;
  }
#endif
  thr->shadow_stack_pos[0] = pc;
  thr->shadow_stack_pos++;
}

ALWAYS_INLINE USED
void FuncExit(ThreadState *thr) {
  DCHECK_EQ(thr->in_rtl, 0);
  StatInc(thr, StatFuncExit);
  DPrintf2("#%d: FuncExit\n", (int)thr->fast_state.tid());
  thr->fast_state.IncrementEpoch();
  TraceAddEvent(thr, thr->fast_state, EventTypeFuncExit, 0);

  DCHECK_GT(thr->shadow_stack_pos, thr->shadow_stack);
#ifndef TSAN_GO
  DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
#endif
  thr->shadow_stack_pos--;
}

void ThreadIgnoreBegin(ThreadState *thr, uptr pc) {
  DPrintf("#%d: ThreadIgnoreBegin\n", thr->tid);
  thr->ignore_reads_and_writes++;
  CHECK_GT(thr->ignore_reads_and_writes, 0);
  thr->fast_state.SetIgnoreBit();
#ifndef TSAN_GO
  thr->mop_ignore_set.Add(CurrentStackId(thr, pc));
#endif
}

void ThreadIgnoreEnd(ThreadState *thr, uptr pc) {
  DPrintf("#%d: ThreadIgnoreEnd\n", thr->tid);
  thr->ignore_reads_and_writes--;
  CHECK_GE(thr->ignore_reads_and_writes, 0);
  if (thr->ignore_reads_and_writes == 0) {
    thr->fast_state.ClearIgnoreBit();
#ifndef TSAN_GO
    thr->mop_ignore_set.Reset();
#endif
  }
}

void ThreadIgnoreSyncBegin(ThreadState *thr, uptr pc) {
  DPrintf("#%d: ThreadIgnoreSyncBegin\n", thr->tid);
  thr->ignore_sync++;
  CHECK_GT(thr->ignore_sync, 0);
#ifndef TSAN_GO
  thr->sync_ignore_set.Add(CurrentStackId(thr, pc));
#endif
}

void ThreadIgnoreSyncEnd(ThreadState *thr, uptr pc) {
  DPrintf("#%d: ThreadIgnoreSyncEnd\n", thr->tid);
  thr->ignore_sync--;
  CHECK_GE(thr->ignore_sync, 0);
#ifndef TSAN_GO
  if (thr->ignore_sync == 0)
    thr->mop_ignore_set.Reset();
#endif
}

bool MD5Hash::operator==(const MD5Hash &other) const {
  return hash[0] == other.hash[0] && hash[1] == other.hash[1];
}

#if TSAN_DEBUG
void build_consistency_debug() {}
#else
void build_consistency_release() {}
#endif

#if TSAN_COLLECT_STATS
void build_consistency_stats() {}
#else
void build_consistency_nostats() {}
#endif

#if TSAN_SHADOW_COUNT == 1
void build_consistency_shadow1() {}
#elif TSAN_SHADOW_COUNT == 2
void build_consistency_shadow2() {}
#elif TSAN_SHADOW_COUNT == 4
void build_consistency_shadow4() {}
#else
void build_consistency_shadow8() {}
#endif

}  // namespace __tsan

#ifndef TSAN_GO
// Must be included in this file to make sure everything is inlined.
#include "tsan_interface_inl.h"
#endif