Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  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
//===-- msan.cpp ----------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of MemorySanitizer.
//
// MemorySanitizer runtime.
//===----------------------------------------------------------------------===//

#include "msan.h"
#include "msan_chained_origin_depot.h"
#include "msan_origin.h"
#include "msan_report.h"
#include "msan_thread.h"
#include "msan_poisoning.h"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_flag_parser.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_procmaps.h"
#include "sanitizer_common/sanitizer_stacktrace.h"
#include "sanitizer_common/sanitizer_symbolizer.h"
#include "sanitizer_common/sanitizer_stackdepot.h"
#include "ubsan/ubsan_flags.h"
#include "ubsan/ubsan_init.h"

// ACHTUNG! No system header includes in this file.

using namespace __sanitizer;

// Globals.
static THREADLOCAL int msan_expect_umr = 0;
static THREADLOCAL int msan_expected_umr_found = 0;

// Function argument shadow. Each argument starts at the next available 8-byte
// aligned address.
SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSize / sizeof(u64)];

// Function argument origin. Each argument starts at the same offset as the
// corresponding shadow in (__msan_param_tls). Slightly weird, but changing this
// would break compatibility with older prebuilt binaries.
SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSize / sizeof(u32)];

SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSize / sizeof(u64)];

SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u32 __msan_retval_origin_tls;

SANITIZER_INTERFACE_ATTRIBUTE
ALIGNED(16) THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];

SANITIZER_INTERFACE_ATTRIBUTE
ALIGNED(16)
THREADLOCAL u32 __msan_va_arg_origin_tls[kMsanParamTlsSize / sizeof(u32)];

SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u64 __msan_va_arg_overflow_size_tls;

SANITIZER_INTERFACE_ATTRIBUTE
THREADLOCAL u32 __msan_origin_tls;

static THREADLOCAL int is_in_symbolizer;

extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins;

int __msan_get_track_origins() {
  return &__msan_track_origins ? __msan_track_origins : 0;
}

extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going;

namespace __msan {

void EnterSymbolizer() { ++is_in_symbolizer; }
void ExitSymbolizer()  { --is_in_symbolizer; }
bool IsInSymbolizer() { return is_in_symbolizer; }

static Flags msan_flags;

Flags *flags() {
  return &msan_flags;
}

int msan_inited = 0;
bool msan_init_is_running;

int msan_report_count = 0;

// Array of stack origins.
// FIXME: make it resizable.
static const uptr kNumStackOriginDescrs = 1024 * 1024;
static const char *StackOriginDescr[kNumStackOriginDescrs];
static uptr StackOriginPC[kNumStackOriginDescrs];
static atomic_uint32_t NumStackOriginDescrs;

void Flags::SetDefaults() {
#define MSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
#include "msan_flags.inc"
#undef MSAN_FLAG
}

// keep_going is an old name for halt_on_error,
// and it has inverse meaning.
class FlagHandlerKeepGoing : public FlagHandlerBase {
  bool *halt_on_error_;

 public:
  explicit FlagHandlerKeepGoing(bool *halt_on_error)
      : halt_on_error_(halt_on_error) {}
  bool Parse(const char *value) final {
    bool tmp;
    FlagHandler<bool> h(&tmp);
    if (!h.Parse(value)) return false;
    *halt_on_error_ = !tmp;
    return true;
  }
  bool Format(char *buffer, uptr size) final {
    const char *keep_going_str = (*halt_on_error_) ? "false" : "true";
    return FormatString(buffer, size, keep_going_str);
  }
};

static void RegisterMsanFlags(FlagParser *parser, Flags *f) {
#define MSAN_FLAG(Type, Name, DefaultValue, Description) \
  RegisterFlag(parser, #Name, Description, &f->Name);
#include "msan_flags.inc"
#undef MSAN_FLAG

  FlagHandlerKeepGoing *fh_keep_going =
      new (FlagParser::Alloc) FlagHandlerKeepGoing(&f->halt_on_error);
  parser->RegisterHandler("keep_going", fh_keep_going,
                          "deprecated, use halt_on_error");
}

static void InitializeFlags() {
  SetCommonFlagsDefaults();
  {
    CommonFlags cf;
    cf.CopyFrom(*common_flags());
    cf.external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH");
    cf.malloc_context_size = 20;
    cf.handle_ioctl = true;
    // FIXME: test and enable.
    cf.check_printf = false;
    cf.intercept_tls_get_addr = true;
    cf.exitcode = 77;
    OverrideCommonFlags(cf);
  }

  Flags *f = flags();
  f->SetDefaults();

  FlagParser parser;
  RegisterMsanFlags(&parser, f);
  RegisterCommonFlags(&parser);

#if MSAN_CONTAINS_UBSAN
  __ubsan::Flags *uf = __ubsan::flags();
  uf->SetDefaults();

  FlagParser ubsan_parser;
  __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
  RegisterCommonFlags(&ubsan_parser);
#endif

  // Override from user-specified string.
  if (__msan_default_options)
    parser.ParseString(__msan_default_options());
#if MSAN_CONTAINS_UBSAN
  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
  ubsan_parser.ParseString(ubsan_default_options);
#endif

  parser.ParseStringFromEnv("MSAN_OPTIONS");
#if MSAN_CONTAINS_UBSAN
  ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
#endif

  InitializeCommonFlags();

  if (Verbosity()) ReportUnrecognizedFlags();

  if (common_flags()->help) parser.PrintFlagDescriptions();

  // Check if deprecated exit_code MSan flag is set.
  if (f->exit_code != -1) {
    if (Verbosity())
      Printf("MSAN_OPTIONS=exit_code is deprecated! "
             "Please use MSAN_OPTIONS=exitcode instead.\n");
    CommonFlags cf;
    cf.CopyFrom(*common_flags());
    cf.exitcode = f->exit_code;
    OverrideCommonFlags(cf);
  }

  // Check flag values:
  if (f->origin_history_size < 0 ||
      f->origin_history_size > Origin::kMaxDepth) {
    Printf(
        "Origin history size invalid: %d. Must be 0 (unlimited) or in [1, %d] "
        "range.\n",
        f->origin_history_size, Origin::kMaxDepth);
    Die();
  }
  // Limiting to kStackDepotMaxUseCount / 2 to avoid overflow in
  // StackDepotHandle::inc_use_count_unsafe.
  if (f->origin_history_per_stack_limit < 0 ||
      f->origin_history_per_stack_limit > kStackDepotMaxUseCount / 2) {
    Printf(
        "Origin per-stack limit invalid: %d. Must be 0 (unlimited) or in [1, "
        "%d] range.\n",
        f->origin_history_per_stack_limit, kStackDepotMaxUseCount / 2);
    Die();
  }
  if (f->store_context_size < 1) f->store_context_size = 1;
}

void PrintWarning(uptr pc, uptr bp) {
  PrintWarningWithOrigin(pc, bp, __msan_origin_tls);
}

void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) {
  if (msan_expect_umr) {
    // Printf("Expected UMR\n");
    __msan_origin_tls = origin;
    msan_expected_umr_found = 1;
    return;
  }

  ++msan_report_count;

  GET_FATAL_STACK_TRACE_PC_BP(pc, bp);

  u32 report_origin =
    (__msan_get_track_origins() && Origin::isValidId(origin)) ? origin : 0;
  ReportUMR(&stack, report_origin);

  if (__msan_get_track_origins() && !Origin::isValidId(origin)) {
    Printf(
        "  ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin "
        "tracking.\n    This could still be a bug in your code, too!\n",
        origin);
  }
}

void UnpoisonParam(uptr n) {
  internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls));
}

// Backup MSan runtime TLS state.
// Implementation must be async-signal-safe.
// Instances of this class may live on the signal handler stack, and data size
// may be an issue.
void ScopedThreadLocalStateBackup::Backup() {
  va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls;
}

void ScopedThreadLocalStateBackup::Restore() {
  // A lame implementation that only keeps essential state and resets the rest.
  __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls;

  internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
  internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
  internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
  internal_memset(__msan_va_arg_origin_tls, 0,
                  sizeof(__msan_va_arg_origin_tls));

  if (__msan_get_track_origins()) {
    internal_memset(&__msan_retval_origin_tls, 0,
                    sizeof(__msan_retval_origin_tls));
    internal_memset(__msan_param_origin_tls, 0,
                    sizeof(__msan_param_origin_tls));
  }
}

void UnpoisonThreadLocalState() {
}

const char *GetStackOriginDescr(u32 id, uptr *pc) {
  CHECK_LT(id, kNumStackOriginDescrs);
  if (pc) *pc = StackOriginPC[id];
  return StackOriginDescr[id];
}

u32 ChainOrigin(u32 id, StackTrace *stack) {
  MsanThread *t = GetCurrentThread();
  if (t && t->InSignalHandler())
    return id;

  Origin o = Origin::FromRawId(id);
  stack->tag = StackTrace::TAG_UNKNOWN;
  Origin chained = Origin::CreateChainedOrigin(o, stack);
  return chained.raw_id();
}

} // namespace __msan

void __sanitizer::BufferedStackTrace::UnwindImpl(
    uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
  using namespace __msan;
  MsanThread *t = GetCurrentThread();
  if (!t || !StackTrace::WillUseFastUnwind(request_fast)) {
    // Block reports from our interceptors during _Unwind_Backtrace.
    SymbolizerScope sym_scope;
    return Unwind(max_depth, pc, bp, context, 0, 0, false);
  }
  if (StackTrace::WillUseFastUnwind(request_fast))
    Unwind(max_depth, pc, bp, nullptr, t->stack_top(), t->stack_bottom(), true);
  else
    Unwind(max_depth, pc, 0, context, 0, 0, false);
}

// Interface.

using namespace __msan;

#define MSAN_MAYBE_WARNING(type, size)              \
  void __msan_maybe_warning_##size(type s, u32 o) { \
    GET_CALLER_PC_BP_SP;                            \
    (void) sp;                                      \
    if (UNLIKELY(s)) {                              \
      PrintWarningWithOrigin(pc, bp, o);            \
      if (__msan::flags()->halt_on_error) {         \
        Printf("Exiting\n");                        \
        Die();                                      \
      }                                             \
    }                                               \
  }

MSAN_MAYBE_WARNING(u8, 1)
MSAN_MAYBE_WARNING(u16, 2)
MSAN_MAYBE_WARNING(u32, 4)
MSAN_MAYBE_WARNING(u64, 8)

#define MSAN_MAYBE_STORE_ORIGIN(type, size)                       \
  void __msan_maybe_store_origin_##size(type s, void *p, u32 o) { \
    if (UNLIKELY(s)) {                                            \
      if (__msan_get_track_origins() > 1) {                       \
        GET_CALLER_PC_BP_SP;                                      \
        (void) sp;                                                \
        GET_STORE_STACK_TRACE_PC_BP(pc, bp);                      \
        o = ChainOrigin(o, &stack);                               \
      }                                                           \
      *(u32 *)MEM_TO_ORIGIN((uptr)p & ~3UL) = o;                  \
    }                                                             \
  }

MSAN_MAYBE_STORE_ORIGIN(u8, 1)
MSAN_MAYBE_STORE_ORIGIN(u16, 2)
MSAN_MAYBE_STORE_ORIGIN(u32, 4)
MSAN_MAYBE_STORE_ORIGIN(u64, 8)

void __msan_warning() {
  GET_CALLER_PC_BP_SP;
  (void)sp;
  PrintWarning(pc, bp);
  if (__msan::flags()->halt_on_error) {
    if (__msan::flags()->print_stats)
      ReportStats();
    Printf("Exiting\n");
    Die();
  }
}

void __msan_warning_noreturn() {
  GET_CALLER_PC_BP_SP;
  (void)sp;
  PrintWarning(pc, bp);
  if (__msan::flags()->print_stats)
    ReportStats();
  Printf("Exiting\n");
  Die();
}

void __msan_warning_with_origin(u32 origin) {
  GET_CALLER_PC_BP_SP;
  (void)sp;
  PrintWarningWithOrigin(pc, bp, origin);
  if (__msan::flags()->halt_on_error) {
    if (__msan::flags()->print_stats)
      ReportStats();
    Printf("Exiting\n");
    Die();
  }
}

void __msan_warning_with_origin_noreturn(u32 origin) {
  GET_CALLER_PC_BP_SP;
  (void)sp;
  PrintWarningWithOrigin(pc, bp, origin);
  if (__msan::flags()->print_stats)
    ReportStats();
  Printf("Exiting\n");
  Die();
}

static void OnStackUnwind(const SignalContext &sig, const void *,
                          BufferedStackTrace *stack) {
  stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
                common_flags()->fast_unwind_on_fatal);
}

static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) {
  HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
}

static void MsanCheckFailed(const char *file, int line, const char *cond,
                            u64 v1, u64 v2) {
  Report("MemorySanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file,
         line, cond, (uptr)v1, (uptr)v2);
  PRINT_CURRENT_STACK_CHECK();
  Die();
}

void __msan_init() {
  CHECK(!msan_init_is_running);
  if (msan_inited) return;
  msan_init_is_running = 1;
  SanitizerToolName = "MemorySanitizer";

  AvoidCVE_2016_2143();

  CacheBinaryName();
  InitializeFlags();

  // Install tool-specific callbacks in sanitizer_common.
  SetCheckFailedCallback(MsanCheckFailed);

  __sanitizer_set_report_path(common_flags()->log_path);

  InitializeInterceptors();
  CheckASLR();
  InitTlsSize();
  InstallDeadlySignalHandlers(MsanOnDeadlySignal);
  InstallAtExitHandler(); // Needs __cxa_atexit interceptor.

  DisableCoreDumperIfNecessary();
  if (StackSizeIsUnlimited()) {
    VPrintf(1, "Unlimited stack, doing reexec\n");
    // A reasonably large stack size. It is bigger than the usual 8Mb, because,
    // well, the program could have been run with unlimited stack for a reason.
    SetStackSizeLimitInBytes(32 * 1024 * 1024);
    ReExec();
  }

  __msan_clear_on_return();
  if (__msan_get_track_origins())
    VPrintf(1, "msan_track_origins\n");
  if (!InitShadow(__msan_get_track_origins())) {
    Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n");
    Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
    Printf("FATAL: Disabling ASLR is known to cause this error.\n");
    Printf("FATAL: If running under GDB, try "
           "'set disable-randomization off'.\n");
    DumpProcessMap();
    Die();
  }

  Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer);

  InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);

  MsanTSDInit(MsanTSDDtor);

  MsanAllocatorInit();

  MsanThread *main_thread = MsanThread::Create(nullptr, nullptr);
  SetCurrentThread(main_thread);
  main_thread->ThreadStart();

#if MSAN_CONTAINS_UBSAN
  __ubsan::InitAsPlugin();
#endif

  VPrintf(1, "MemorySanitizer init done\n");

  msan_init_is_running = 0;
  msan_inited = 1;
}

void __msan_set_keep_going(int keep_going) {
  flags()->halt_on_error = !keep_going;
}

void __msan_set_expect_umr(int expect_umr) {
  if (expect_umr) {
    msan_expected_umr_found = 0;
  } else if (!msan_expected_umr_found) {
    GET_CALLER_PC_BP_SP;
    (void)sp;
    GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
    ReportExpectedUMRNotFound(&stack);
    Die();
  }
  msan_expect_umr = expect_umr;
}

void __msan_print_shadow(const void *x, uptr size) {
  if (!MEM_IS_APP(x)) {
    Printf("Not a valid application address: %p\n", x);
    return;
  }

  DescribeMemoryRange(x, size);
}

void __msan_dump_shadow(const void *x, uptr size) {
  if (!MEM_IS_APP(x)) {
    Printf("Not a valid application address: %p\n", x);
    return;
  }

  unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x);
  for (uptr i = 0; i < size; i++)
    Printf("%x%x ", s[i] >> 4, s[i] & 0xf);
  Printf("\n");
}

sptr __msan_test_shadow(const void *x, uptr size) {
  if (!MEM_IS_APP(x)) return -1;
  unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x);
  for (uptr i = 0; i < size; ++i)
    if (s[i])
      return i;
  return -1;
}

void __msan_check_mem_is_initialized(const void *x, uptr size) {
  if (!__msan::flags()->report_umrs) return;
  sptr offset = __msan_test_shadow(x, size);
  if (offset < 0)
    return;

  GET_CALLER_PC_BP_SP;
  (void)sp;
  ReportUMRInsideAddressRange(__func__, x, size, offset);
  __msan::PrintWarningWithOrigin(pc, bp,
                                 __msan_get_origin(((const char *)x) + offset));
  if (__msan::flags()->halt_on_error) {
    Printf("Exiting\n");
    Die();
  }
}

int __msan_set_poison_in_malloc(int do_poison) {
  int old = flags()->poison_in_malloc;
  flags()->poison_in_malloc = do_poison;
  return old;
}

int __msan_has_dynamic_component() { return false; }

NOINLINE
void __msan_clear_on_return() {
  __msan_param_tls[0] = 0;
}

void __msan_partial_poison(const void* data, void* shadow, uptr size) {
  internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size);
}

void __msan_load_unpoisoned(const void *src, uptr size, void *dst) {
  internal_memcpy(dst, src, size);
  __msan_unpoison(dst, size);
}

void __msan_set_origin(const void *a, uptr size, u32 origin) {
  if (__msan_get_track_origins()) SetOrigin(a, size, origin);
}

// 'descr' is created at compile time and contains '----' in the beginning.
// When we see descr for the first time we replace '----' with a uniq id
// and set the origin to (id | (31-th bit)).
void __msan_set_alloca_origin(void *a, uptr size, char *descr) {
  __msan_set_alloca_origin4(a, size, descr, 0);
}

void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
  static const u32 dash = '-';
  static const u32 first_timer =
      dash + (dash << 8) + (dash << 16) + (dash << 24);
  u32 *id_ptr = (u32*)descr;
  bool print = false;  // internal_strstr(descr + 4, "AllocaTOTest") != 0;
  u32 id = *id_ptr;
  if (id == first_timer) {
    u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
    CHECK_LT(idx, kNumStackOriginDescrs);
    StackOriginDescr[idx] = descr + 4;
#if SANITIZER_PPC64V1
    // On PowerPC64 ELFv1, the address of a function actually points to a
    // three-doubleword data structure with the first field containing
    // the address of the function's code.
    if (pc)
      pc = *reinterpret_cast<uptr*>(pc);
#endif
    StackOriginPC[idx] = pc;
    id = Origin::CreateStackOrigin(idx).raw_id();
    *id_ptr = id;
    if (print)
      Printf("First time: idx=%d id=%d %s %p \n", idx, id, descr + 4, pc);
  }
  if (print)
    Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id);
  __msan_set_origin(a, size, id);
}

u32 __msan_chain_origin(u32 id) {
  GET_CALLER_PC_BP_SP;
  (void)sp;
  GET_STORE_STACK_TRACE_PC_BP(pc, bp);
  return ChainOrigin(id, &stack);
}

u32 __msan_get_origin(const void *a) {
  if (!__msan_get_track_origins()) return 0;
  uptr x = (uptr)a;
  uptr aligned = x & ~3ULL;
  uptr origin_ptr = MEM_TO_ORIGIN(aligned);
  return *(u32*)origin_ptr;
}

int __msan_origin_is_descendant_or_same(u32 this_id, u32 prev_id) {
  Origin o = Origin::FromRawId(this_id);
  while (o.raw_id() != prev_id && o.isChainedOrigin())
    o = o.getNextChainedOrigin(nullptr);
  return o.raw_id() == prev_id;
}

u32 __msan_get_umr_origin() {
  return __msan_origin_tls;
}

u16 __sanitizer_unaligned_load16(const uu16 *p) {
  internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
                  sizeof(uu16));
  if (__msan_get_track_origins())
    __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
  return *p;
}
u32 __sanitizer_unaligned_load32(const uu32 *p) {
  internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
                  sizeof(uu32));
  if (__msan_get_track_origins())
    __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
  return *p;
}
u64 __sanitizer_unaligned_load64(const uu64 *p) {
  internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
                  sizeof(uu64));
  if (__msan_get_track_origins())
    __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
  return *p;
}
void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
  static_assert(sizeof(uu16) == sizeof(u16), "incompatible types");
  u16 s;
  internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu16));
  internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu16));
  if (s && __msan_get_track_origins())
    if (uu32 o = __msan_param_origin_tls[2])
      SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
  *p = x;
}
void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
  static_assert(sizeof(uu32) == sizeof(u32), "incompatible types");
  u32 s;
  internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu32));
  internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu32));
  if (s && __msan_get_track_origins())
    if (uu32 o = __msan_param_origin_tls[2])
      SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
  *p = x;
}
void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
  u64 s = __msan_param_tls[1];
  *(uu64 *)MEM_TO_SHADOW((uptr)p) = s;
  if (s && __msan_get_track_origins())
    if (uu32 o = __msan_param_origin_tls[2])
      SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
  *p = x;
}

void __msan_set_death_callback(void (*callback)(void)) {
  SetUserDieCallback(callback);
}

#if !SANITIZER_SUPPORTS_WEAK_HOOKS
extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
const char* __msan_default_options() { return ""; }
}  // extern "C"
#endif

extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE
void __sanitizer_print_stack_trace() {
  GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
  stack.Print();
}
} // extern "C"