compiler-rt/lib/msan/msan.cpp

   1 //===-- msan.cpp ----------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of MemorySanitizer.
  10 //
  11 // MemorySanitizer runtime.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "msan.h"
  15
  16 #include "msan_chained_origin_depot.h"
  17 #include "msan_origin.h"
  18 #include "msan_poisoning.h"
  19 #include "msan_report.h"
  20 #include "msan_thread.h"
  21 #include "sanitizer_common/sanitizer_atomic.h"
  22 #include "sanitizer_common/sanitizer_common.h"
  23 #include "sanitizer_common/sanitizer_flag_parser.h"
  24 #include "sanitizer_common/sanitizer_flags.h"
  25 #include "sanitizer_common/sanitizer_interface_internal.h"
  26 #include "sanitizer_common/sanitizer_libc.h"
  27 #include "sanitizer_common/sanitizer_procmaps.h"
  28 #include "sanitizer_common/sanitizer_stackdepot.h"
  29 #include "sanitizer_common/sanitizer_stacktrace.h"
  30 #include "sanitizer_common/sanitizer_symbolizer.h"
  31 #include "ubsan/ubsan_flags.h"
  32 #include "ubsan/ubsan_init.h"
  33
  34 // ACHTUNG! No system header includes in this file.
  35
  36 using namespace __sanitizer;
  37
  38 // Globals.
  39 static THREADLOCAL int msan_expect_umr = 0;
  40 static THREADLOCAL int msan_expected_umr_found = 0;
  41
  42 // Function argument shadow. Each argument starts at the next available 8-byte
  43 // aligned address.
  44 SANITIZER_INTERFACE_ATTRIBUTE
  45 THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSize / sizeof(u64)];
  46
  47 // Function argument origin. Each argument starts at the same offset as the
  48 // corresponding shadow in (__msan_param_tls). Slightly weird, but changing this
  49 // would break compatibility with older prebuilt binaries.
  50 SANITIZER_INTERFACE_ATTRIBUTE
  51 THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSize / sizeof(u32)];
  52
  53 SANITIZER_INTERFACE_ATTRIBUTE
  54 THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSize / sizeof(u64)];
  55
  56 SANITIZER_INTERFACE_ATTRIBUTE
  57 THREADLOCAL u32 __msan_retval_origin_tls;
  58
  59 alignas(16) SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u64
  60     __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];
  61
  62 alignas(16) SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u32
  63     __msan_va_arg_origin_tls[kMsanParamTlsSize / sizeof(u32)];
  64
  65 SANITIZER_INTERFACE_ATTRIBUTE
  66 THREADLOCAL u64 __msan_va_arg_overflow_size_tls;
  67
  68 SANITIZER_INTERFACE_ATTRIBUTE
  69 THREADLOCAL u32 __msan_origin_tls;
  70
  71 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins;
  72
  73 int __msan_get_track_origins() {
  74   return &__msan_track_origins ? __msan_track_origins : 0;
  75 }
  76
  77 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going;
  78
  79 namespace __msan {
  80
  81 static THREADLOCAL int is_in_symbolizer_or_unwinder;
  82 static void EnterSymbolizerOrUnwider() { ++is_in_symbolizer_or_unwinder; }
  83 static void ExitSymbolizerOrUnwider() { --is_in_symbolizer_or_unwinder; }
  84 bool IsInSymbolizerOrUnwider() { return is_in_symbolizer_or_unwinder; }
  85
  86 struct UnwinderScope {
  87   UnwinderScope() { EnterSymbolizerOrUnwider(); }
  88   ~UnwinderScope() { ExitSymbolizerOrUnwider(); }
  89 };
  90
  91 static Flags msan_flags;
  92
  93 Flags *flags() { return &msan_flags; }
  94
  95 int msan_inited = 0;
  96 bool msan_init_is_running;
  97
  98 int msan_report_count = 0;
  99
 100 // Array of stack origins.
 101 // FIXME: make it resizable.
 102 // Although BSS memory doesn't cost anything until used, it is limited to 2GB
 103 // in some configurations (e.g., "relocation R_X86_64_PC32 out of range:
 104 // ... is not in [-2147483648, 2147483647]; references section '.bss'").
 105 // We use kNumStackOriginDescrs * (sizeof(char*) + sizeof(uptr)) == 64MB.
 106 #if SANITIZER_PPC
 107 // soft_rss_limit test (release_origin.c) fails on PPC if kNumStackOriginDescrs
 108 // is too high
 109 static const uptr kNumStackOriginDescrs = 1 * 1024 * 1024;
 110 #else
 111 static const uptr kNumStackOriginDescrs = 4 * 1024 * 1024;
 112 #endif  // SANITIZER_PPC
 113 static const char *StackOriginDescr[kNumStackOriginDescrs];
 114 static uptr StackOriginPC[kNumStackOriginDescrs];
 115 static atomic_uint32_t NumStackOriginDescrs;
 116
 117 void Flags::SetDefaults() {
 118 #define MSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
 119 #include "msan_flags.inc"
 120 #undef MSAN_FLAG
 121 }
 122
 123 // keep_going is an old name for halt_on_error,
 124 // and it has inverse meaning.
 125 class FlagHandlerKeepGoing final : public FlagHandlerBase {
 126   bool *halt_on_error_;
 127
 128  public:
 129   explicit FlagHandlerKeepGoing(bool *halt_on_error)
 130       : halt_on_error_(halt_on_error) {}
 131   bool Parse(const char *value) final {
 132     bool tmp;
 133     FlagHandler<bool> h(&tmp);
 134     if (!h.Parse(value)) return false;
 135     *halt_on_error_ = !tmp;
 136     return true;
 137   }
 138   bool Format(char *buffer, uptr size) final {
 139     const char *keep_going_str = (*halt_on_error_) ? "false" : "true";
 140     return FormatString(buffer, size, keep_going_str);
 141   }
 142 };
 143
 144 static void RegisterMsanFlags(FlagParser *parser, Flags *f) {
 145 #define MSAN_FLAG(Type, Name, DefaultValue, Description) \
 146   RegisterFlag(parser, #Name, Description, &f->Name);
 147 #include "msan_flags.inc"
 148 #undef MSAN_FLAG
 149
 150   FlagHandlerKeepGoing *fh_keep_going = new (GetGlobalLowLevelAllocator())
 151       FlagHandlerKeepGoing(&f->halt_on_error);
 152   parser->RegisterHandler("keep_going", fh_keep_going,
 153                           "deprecated, use halt_on_error");
 154 }
 155
 156 static void InitializeFlags() {
 157   SetCommonFlagsDefaults();
 158   {
 159     CommonFlags cf;
 160     cf.CopyFrom(*common_flags());
 161     cf.external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH");
 162     cf.malloc_context_size = 20;
 163     cf.handle_ioctl = true;
 164     // FIXME: test and enable.
 165     cf.check_printf = false;
 166     cf.intercept_tls_get_addr = true;
 167     OverrideCommonFlags(cf);
 168   }
 169
 170   Flags *f = flags();
 171   f->SetDefaults();
 172
 173   FlagParser parser;
 174   RegisterMsanFlags(&parser, f);
 175   RegisterCommonFlags(&parser);
 176
 177 #if MSAN_CONTAINS_UBSAN
 178   __ubsan::Flags *uf = __ubsan::flags();
 179   uf->SetDefaults();
 180
 181   FlagParser ubsan_parser;
 182   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
 183   RegisterCommonFlags(&ubsan_parser);
 184 #endif
 185
 186   // Override from user-specified string.
 187   parser.ParseString(__msan_default_options());
 188 #if MSAN_CONTAINS_UBSAN
 189   const char *ubsan_default_options = __ubsan_default_options();
 190   ubsan_parser.ParseString(ubsan_default_options);
 191 #endif
 192
 193   parser.ParseStringFromEnv("MSAN_OPTIONS");
 194 #if MSAN_CONTAINS_UBSAN
 195   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
 196 #endif
 197
 198   InitializeCommonFlags();
 199
 200   if (Verbosity()) ReportUnrecognizedFlags();
 201
 202   if (common_flags()->help) parser.PrintFlagDescriptions();
 203
 204   // Check if deprecated exit_code MSan flag is set.
 205   if (f->exit_code != -1) {
 206     if (Verbosity())
 207       Printf("MSAN_OPTIONS=exit_code is deprecated! "
 208              "Please use MSAN_OPTIONS=exitcode instead.\n");
 209     CommonFlags cf;
 210     cf.CopyFrom(*common_flags());
 211     cf.exitcode = f->exit_code;
 212     OverrideCommonFlags(cf);
 213   }
 214
 215   // Check flag values:
 216   if (f->origin_history_size < 0 ||
 217       f->origin_history_size > Origin::kMaxDepth) {
 218     Printf(
 219         "Origin history size invalid: %d. Must be 0 (unlimited) or in [1, %d] "
 220         "range.\n",
 221         f->origin_history_size, Origin::kMaxDepth);
 222     Die();
 223   }
 224   // Limiting to kStackDepotMaxUseCount / 2 to avoid overflow in
 225   // StackDepotHandle::inc_use_count_unsafe.
 226   if (f->origin_history_per_stack_limit < 0 ||
 227       f->origin_history_per_stack_limit > kStackDepotMaxUseCount / 2) {
 228     Printf(
 229         "Origin per-stack limit invalid: %d. Must be 0 (unlimited) or in [1, "
 230         "%d] range.\n",
 231         f->origin_history_per_stack_limit, kStackDepotMaxUseCount / 2);
 232     Die();
 233   }
 234   if (f->store_context_size < 1) f->store_context_size = 1;
 235 }
 236
 237 void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) {
 238   if (msan_expect_umr) {
 239     // Printf("Expected UMR\n");
 240     __msan_origin_tls = origin;
 241     msan_expected_umr_found = 1;
 242     return;
 243   }
 244
 245   ++msan_report_count;
 246
 247   GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
 248
 249   u32 report_origin =
 250     (__msan_get_track_origins() && Origin::isValidId(origin)) ? origin : 0;
 251   ReportUMR(&stack, report_origin);
 252
 253   if (__msan_get_track_origins() && !Origin::isValidId(origin)) {
 254     Printf(
 255         "  ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin "
 256         "tracking.\n    This could still be a bug in your code, too!\n",
 257         origin);
 258   }
 259 }
 260
 261 void UnpoisonParam(uptr n) {
 262   internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls));
 263 }
 264
 265 // Backup MSan runtime TLS state.
 266 // Implementation must be async-signal-safe.
 267 // Instances of this class may live on the signal handler stack, and data size
 268 // may be an issue.
 269 void ScopedThreadLocalStateBackup::Backup() {
 270   va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls;
 271 }
 272
 273 void ScopedThreadLocalStateBackup::Restore() {
 274   // A lame implementation that only keeps essential state and resets the rest.
 275   __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls;
 276
 277   internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
 278   internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
 279   internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
 280   internal_memset(__msan_va_arg_origin_tls, 0,
 281                   sizeof(__msan_va_arg_origin_tls));
 282
 283   if (__msan_get_track_origins()) {
 284     internal_memset(&__msan_retval_origin_tls, 0,
 285                     sizeof(__msan_retval_origin_tls));
 286     internal_memset(__msan_param_origin_tls, 0,
 287                     sizeof(__msan_param_origin_tls));
 288   }
 289 }
 290
 291 void UnpoisonThreadLocalState() {
 292 }
 293
 294 const char *GetStackOriginDescr(u32 id, uptr *pc) {
 295   CHECK_LT(id, kNumStackOriginDescrs);
 296   if (pc) *pc = StackOriginPC[id];
 297   return StackOriginDescr[id];
 298 }
 299
 300 u32 ChainOrigin(u32 id, StackTrace *stack) {
 301   MsanThread *t = GetCurrentThread();
 302   if (t && t->InSignalHandler())
 303     return id;
 304
 305   Origin o = Origin::FromRawId(id);
 306   stack->tag = StackTrace::TAG_UNKNOWN;
 307   Origin chained = Origin::CreateChainedOrigin(o, stack);
 308   return chained.raw_id();
 309 }
 310
 311 // Current implementation separates the 'id_ptr' from the 'descr' and makes
 312 // 'descr' constant.
 313 // Previous implementation 'descr' is created at compile time and contains
 314 // '----' in the beginning.  When we see descr for the first time we replace
 315 // '----' with a uniq id and set the origin to (id | (31-th bit)).
 316 static inline void SetAllocaOrigin(void *a, uptr size, u32 *id_ptr, char *descr,
 317                                    uptr pc) {
 318   static const u32 dash = '-';
 319   static const u32 first_timer =
 320       dash + (dash << 8) + (dash << 16) + (dash << 24);
 321   u32 id = *id_ptr;
 322   if (id == 0 || id == first_timer) {
 323     u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
 324     CHECK_LT(idx, kNumStackOriginDescrs);
 325     StackOriginDescr[idx] = descr;
 326     StackOriginPC[idx] = pc;
 327     id = Origin::CreateStackOrigin(idx).raw_id();
 328     *id_ptr = id;
 329   }
 330   __msan_set_origin(a, size, id);
 331 }
 332
 333 }  // namespace __msan
 334
 335 void __sanitizer::BufferedStackTrace::UnwindImpl(
 336     uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
 337   using namespace __msan;
 338   MsanThread *t = GetCurrentThread();
 339   if (!t || !StackTrace::WillUseFastUnwind(request_fast)) {
 340     // Block reports from our interceptors during _Unwind_Backtrace.
 341     UnwinderScope sym_scope;
 342     return Unwind(max_depth, pc, bp, context, t ? t->stack_top() : 0,
 343                   t ? t->stack_bottom() : 0, false);
 344   }
 345   if (StackTrace::WillUseFastUnwind(request_fast))
 346     Unwind(max_depth, pc, bp, nullptr, t->stack_top(), t->stack_bottom(), true);
 347   else
 348     Unwind(max_depth, pc, 0, context, 0, 0, false);
 349 }
 350
 351 // Interface.
 352
 353 using namespace __msan;
 354
 355 #define MSAN_MAYBE_WARNING(type, size)              \
 356   void __msan_maybe_warning_##size(type s, u32 o) { \
 357     GET_CALLER_PC_BP;                               \
 358     if (UNLIKELY(s)) {                              \
 359       PrintWarningWithOrigin(pc, bp, o);            \
 360       if (__msan::flags()->halt_on_error) {         \
 361         Printf("Exiting\n");                        \
 362         Die();                                      \
 363       }                                             \
 364     }                                               \
 365   }
 366
 367 MSAN_MAYBE_WARNING(u8, 1)
 368 MSAN_MAYBE_WARNING(u16, 2)
 369 MSAN_MAYBE_WARNING(u32, 4)
 370 MSAN_MAYBE_WARNING(u64, 8)
 371
 372 #define MSAN_MAYBE_STORE_ORIGIN(type, size)                       \
 373   void __msan_maybe_store_origin_##size(type s, void *p, u32 o) { \
 374     if (UNLIKELY(s)) {                                            \
 375       if (__msan_get_track_origins() > 1) {                       \
 376         GET_CALLER_PC_BP;                                         \
 377         GET_STORE_STACK_TRACE_PC_BP(pc, bp);                      \
 378         o = ChainOrigin(o, &stack);                               \
 379       }                                                           \
 380       *(u32 *)MEM_TO_ORIGIN((uptr)p & ~3UL) = o;                  \
 381     }                                                             \
 382   }
 383
 384 MSAN_MAYBE_STORE_ORIGIN(u8, 1)
 385 MSAN_MAYBE_STORE_ORIGIN(u16, 2)
 386 MSAN_MAYBE_STORE_ORIGIN(u32, 4)
 387 MSAN_MAYBE_STORE_ORIGIN(u64, 8)
 388
 389 void __msan_warning() {
 390   GET_CALLER_PC_BP;
 391   PrintWarningWithOrigin(pc, bp, 0);
 392   if (__msan::flags()->halt_on_error) {
 393     if (__msan::flags()->print_stats)
 394       ReportStats();
 395     Printf("Exiting\n");
 396     Die();
 397   }
 398 }
 399
 400 void __msan_warning_noreturn() {
 401   GET_CALLER_PC_BP;
 402   PrintWarningWithOrigin(pc, bp, 0);
 403   if (__msan::flags()->print_stats)
 404     ReportStats();
 405   Printf("Exiting\n");
 406   Die();
 407 }
 408
 409 void __msan_warning_with_origin(u32 origin) {
 410   GET_CALLER_PC_BP;
 411   PrintWarningWithOrigin(pc, bp, origin);
 412   if (__msan::flags()->halt_on_error) {
 413     if (__msan::flags()->print_stats)
 414       ReportStats();
 415     Printf("Exiting\n");
 416     Die();
 417   }
 418 }
 419
 420 void __msan_warning_with_origin_noreturn(u32 origin) {
 421   GET_CALLER_PC_BP;
 422   PrintWarningWithOrigin(pc, bp, origin);
 423   if (__msan::flags()->print_stats)
 424     ReportStats();
 425   Printf("Exiting\n");
 426   Die();
 427 }
 428
 429 static void OnStackUnwind(const SignalContext &sig, const void *,
 430                           BufferedStackTrace *stack) {
 431   stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
 432                 common_flags()->fast_unwind_on_fatal);
 433 }
 434
 435 static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) {
 436   HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
 437 }
 438
 439 static void CheckUnwind() {
 440   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
 441   stack.Print();
 442 }
 443
 444 void __msan_init() {
 445   CHECK(!msan_init_is_running);
 446   if (msan_inited) return;
 447   msan_init_is_running = 1;
 448   SanitizerToolName = "MemorySanitizer";
 449
 450   AvoidCVE_2016_2143();
 451
 452   CacheBinaryName();
 453   InitializeFlags();
 454
 455   // Install tool-specific callbacks in sanitizer_common.
 456   SetCheckUnwindCallback(CheckUnwind);
 457
 458   __sanitizer_set_report_path(common_flags()->log_path);
 459
 460   InitializePlatformEarly();
 461
 462   InitializeInterceptors();
 463   InstallAtForkHandler();
 464   CheckASLR();
 465   InstallDeadlySignalHandlers(MsanOnDeadlySignal);
 466   InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
 467
 468   DisableCoreDumperIfNecessary();
 469   if (StackSizeIsUnlimited()) {
 470     VPrintf(1, "Unlimited stack, doing reexec\n");
 471     // A reasonably large stack size. It is bigger than the usual 8Mb, because,
 472     // well, the program could have been run with unlimited stack for a reason.
 473     SetStackSizeLimitInBytes(32 * 1024 * 1024);
 474     ReExec();
 475   }
 476
 477   __msan_clear_on_return();
 478   if (__msan_get_track_origins())
 479     VPrintf(1, "msan_track_origins\n");
 480   if (!InitShadowWithReExec(__msan_get_track_origins())) {
 481     Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n");
 482     Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
 483     Printf("FATAL: Disabling ASLR is known to cause this error.\n");
 484     Printf("FATAL: If running under GDB, try "
 485            "'set disable-randomization off'.\n");
 486     DumpProcessMap();
 487     Die();
 488   }
 489
 490   Symbolizer::GetOrInit()->AddHooks(EnterSymbolizerOrUnwider,
 491                                     ExitSymbolizerOrUnwider);
 492
 493   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
 494
 495   MsanTSDInit(MsanTSDDtor);
 496
 497   MsanAllocatorInit();
 498
 499   MsanThread *main_thread = MsanThread::Create(nullptr, nullptr);
 500   SetCurrentThread(main_thread);
 501   main_thread->Init();
 502
 503 #if MSAN_CONTAINS_UBSAN
 504   __ubsan::InitAsPlugin();
 505 #endif
 506
 507   VPrintf(1, "MemorySanitizer init done\n");
 508
 509   msan_init_is_running = 0;
 510   msan_inited = 1;
 511 }
 512
 513 void __msan_set_keep_going(int keep_going) {
 514   flags()->halt_on_error = !keep_going;
 515 }
 516
 517 void __msan_set_expect_umr(int expect_umr) {
 518   if (expect_umr) {
 519     msan_expected_umr_found = 0;
 520   } else if (!msan_expected_umr_found) {
 521     GET_CALLER_PC_BP;
 522     GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
 523     ReportExpectedUMRNotFound(&stack);
 524     Die();
 525   }
 526   msan_expect_umr = expect_umr;
 527 }
 528
 529 void __msan_print_shadow(const void *x, uptr size) {
 530   if (!MEM_IS_APP(x)) {
 531     Printf("Not a valid application address: %p\n", x);
 532     return;
 533   }
 534
 535   DescribeMemoryRange(x, size);
 536 }
 537
 538 void __msan_dump_shadow(const void *x, uptr size) {
 539   if (!MEM_IS_APP(x)) {
 540     Printf("Not a valid application address: %p\n", x);
 541     return;
 542   }
 543
 544   unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x);
 545   Printf("%p[%p]  ", (void *)s, x);
 546   for (uptr i = 0; i < size; i++)
 547     Printf("%x%x ", s[i] >> 4, s[i] & 0xf);
 548   Printf("\n");
 549 }
 550
 551 sptr __msan_test_shadow(const void *x, uptr size) {
 552   if (!MEM_IS_APP(x)) return -1;
 553   unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x);
 554   if (__sanitizer::mem_is_zero((const char *)s, size))
 555     return -1;
 556   // Slow path: loop through again to find the location.
 557   for (uptr i = 0; i < size; ++i)
 558     if (s[i])
 559       return i;
 560   return -1;
 561 }
 562
 563 void __msan_check_mem_is_initialized(const void *x, uptr size) {
 564   if (!__msan::flags()->report_umrs) return;
 565   sptr offset = __msan_test_shadow(x, size);
 566   if (offset < 0)
 567     return;
 568
 569   GET_CALLER_PC_BP;
 570   ReportUMRInsideAddressRange(__func__, x, size, offset);
 571   __msan::PrintWarningWithOrigin(pc, bp,
 572                                  __msan_get_origin(((const char *)x) + offset));
 573   if (__msan::flags()->halt_on_error) {
 574     Printf("Exiting\n");
 575     Die();
 576   }
 577 }
 578
 579 int __msan_set_poison_in_malloc(int do_poison) {
 580   int old = flags()->poison_in_malloc;
 581   flags()->poison_in_malloc = do_poison;
 582   return old;
 583 }
 584
 585 int __msan_has_dynamic_component() { return false; }
 586
 587 NOINLINE
 588 void __msan_clear_on_return() {
 589   __msan_param_tls[0] = 0;
 590 }
 591
 592 void __msan_partial_poison(const void* data, void* shadow, uptr size) {
 593   internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size);
 594 }
 595
 596 void __msan_load_unpoisoned(const void *src, uptr size, void *dst) {
 597   internal_memcpy(dst, src, size);
 598   __msan_unpoison(dst, size);
 599 }
 600
 601 void __msan_set_origin(const void *a, uptr size, u32 origin) {
 602   if (__msan_get_track_origins()) SetOrigin(a, size, origin);
 603 }
 604
 605 void __msan_set_alloca_origin(void *a, uptr size, char *descr) {
 606   SetAllocaOrigin(a, size, reinterpret_cast<u32 *>(descr), descr + 4,
 607                   GET_CALLER_PC());
 608 }
 609
 610 void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
 611   // Intentionally ignore pc and use return address. This function is here for
 612   // compatibility, in case program is linked with library instrumented by
 613   // older clang.
 614   SetAllocaOrigin(a, size, reinterpret_cast<u32 *>(descr), descr + 4,
 615                   GET_CALLER_PC());
 616 }
 617
 618 void __msan_set_alloca_origin_with_descr(void *a, uptr size, u32 *id_ptr,
 619                                          char *descr) {
 620   SetAllocaOrigin(a, size, id_ptr, descr, GET_CALLER_PC());
 621 }
 622
 623 void __msan_set_alloca_origin_no_descr(void *a, uptr size, u32 *id_ptr) {
 624   SetAllocaOrigin(a, size, id_ptr, nullptr, GET_CALLER_PC());
 625 }
 626
 627 u32 __msan_chain_origin(u32 id) {
 628   GET_CALLER_PC_BP;
 629   GET_STORE_STACK_TRACE_PC_BP(pc, bp);
 630   return ChainOrigin(id, &stack);
 631 }
 632
 633 u32 __msan_get_origin(const void *a) {
 634   if (!__msan_get_track_origins()) return 0;
 635   uptr x = (uptr)a;
 636   uptr aligned = x & ~3ULL;
 637   uptr origin_ptr = MEM_TO_ORIGIN(aligned);
 638   return *(u32*)origin_ptr;
 639 }
 640
 641 int __msan_origin_is_descendant_or_same(u32 this_id, u32 prev_id) {
 642   Origin o = Origin::FromRawId(this_id);
 643   while (o.raw_id() != prev_id && o.isChainedOrigin())
 644     o = o.getNextChainedOrigin(nullptr);
 645   return o.raw_id() == prev_id;
 646 }
 647
 648 u32 __msan_get_umr_origin() {
 649   return __msan_origin_tls;
 650 }
 651
 652 u16 __sanitizer_unaligned_load16(const uu16 *p) {
 653   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
 654                   sizeof(uu16));
 655   if (__msan_get_track_origins())
 656     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
 657   return *p;
 658 }
 659 u32 __sanitizer_unaligned_load32(const uu32 *p) {
 660   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
 661                   sizeof(uu32));
 662   if (__msan_get_track_origins())
 663     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
 664   return *p;
 665 }
 666 u64 __sanitizer_unaligned_load64(const uu64 *p) {
 667   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
 668                   sizeof(uu64));
 669   if (__msan_get_track_origins())
 670     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
 671   return *p;
 672 }
 673 void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
 674   static_assert(sizeof(uu16) == sizeof(u16), "incompatible types");
 675   u16 s;
 676   internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu16));
 677   internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu16));
 678   if (s && __msan_get_track_origins())
 679     if (uu32 o = __msan_param_origin_tls[2])
 680       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
 681   *p = x;
 682 }
 683 void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
 684   static_assert(sizeof(uu32) == sizeof(u32), "incompatible types");
 685   u32 s;
 686   internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu32));
 687   internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu32));
 688   if (s && __msan_get_track_origins())
 689     if (uu32 o = __msan_param_origin_tls[2])
 690       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
 691   *p = x;
 692 }
 693 void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
 694   u64 s = __msan_param_tls[1];
 695   *(uu64 *)MEM_TO_SHADOW((uptr)p) = s;
 696   if (s && __msan_get_track_origins())
 697     if (uu32 o = __msan_param_origin_tls[2])
 698       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
 699   *p = x;
 700 }
 701
 702 void __msan_set_death_callback(void (*callback)(void)) {
 703   SetUserDieCallback(callback);
 704 }
 705
 706 void __msan_start_switch_fiber(const void *bottom, uptr size) {
 707   MsanThread *t = GetCurrentThread();
 708   if (!t) {
 709     VReport(1, "__msan_start_switch_fiber called from unknown thread\n");
 710     return;
 711   }
 712   t->StartSwitchFiber((uptr)bottom, size);
 713 }
 714
 715 void __msan_finish_switch_fiber(const void **bottom_old, uptr *size_old) {
 716   MsanThread *t = GetCurrentThread();
 717   if (!t) {
 718     VReport(1, "__msan_finish_switch_fiber called from unknown thread\n");
 719     return;
 720   }
 721   t->FinishSwitchFiber((uptr *)bottom_old, (uptr *)size_old);
 722
 723   internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
 724   internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
 725   internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
 726
 727   if (__msan_get_track_origins()) {
 728     internal_memset(__msan_param_origin_tls, 0,
 729                     sizeof(__msan_param_origin_tls));
 730     internal_memset(&__msan_retval_origin_tls, 0,
 731                     sizeof(__msan_retval_origin_tls));
 732     internal_memset(__msan_va_arg_origin_tls, 0,
 733                     sizeof(__msan_va_arg_origin_tls));
 734   }
 735 }
 736
 737 SANITIZER_INTERFACE_WEAK_DEF(const char *, __msan_default_options, void) {
 738   return "";
 739 }
 740
 741 extern "C" {
 742 SANITIZER_INTERFACE_ATTRIBUTE
 743 void __sanitizer_print_stack_trace() {
 744   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
 745   stack.Print();
 746 }
 747 } // extern "C"