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      1 //===-- tsan_rtl.cc -------------------------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file is a part of ThreadSanitizer (TSan), a race detector.
     11 //
     12 // Main file (entry points) for the TSan run-time.
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "sanitizer_common/sanitizer_atomic.h"
     16 #include "sanitizer_common/sanitizer_common.h"
     17 #include "sanitizer_common/sanitizer_libc.h"
     18 #include "sanitizer_common/sanitizer_stackdepot.h"
     19 #include "sanitizer_common/sanitizer_placement_new.h"
     20 #include "sanitizer_common/sanitizer_symbolizer.h"
     21 #include "tsan_defs.h"
     22 #include "tsan_platform.h"
     23 #include "tsan_rtl.h"
     24 #include "tsan_mman.h"
     25 #include "tsan_suppressions.h"
     26 #include "tsan_symbolize.h"
     27 #include "ubsan/ubsan_init.h"
     28 
     29 #ifdef __SSE3__
     30 // <emmintrin.h> transitively includes <stdlib.h>,
     31 // and it's prohibited to include std headers into tsan runtime.
     32 // So we do this dirty trick.
     33 #define _MM_MALLOC_H_INCLUDED
     34 #define __MM_MALLOC_H
     35 #include <emmintrin.h>
     36 typedef __m128i m128;
     37 #endif
     38 
     39 volatile int __tsan_resumed = 0;
     40 
     41 extern "C" void __tsan_resume() {
     42   __tsan_resumed = 1;
     43 }
     44 
     45 namespace __tsan {
     46 
     47 #if !defined(SANITIZER_GO) && !SANITIZER_MAC
     48 THREADLOCAL char cur_thread_placeholder[sizeof(ThreadState)] ALIGNED(64);
     49 #endif
     50 static char ctx_placeholder[sizeof(Context)] ALIGNED(64);
     51 Context *ctx;
     52 
     53 // Can be overriden by a front-end.
     54 #ifdef TSAN_EXTERNAL_HOOKS
     55 bool OnFinalize(bool failed);
     56 void OnInitialize();
     57 #else
     58 SANITIZER_WEAK_CXX_DEFAULT_IMPL
     59 bool OnFinalize(bool failed) {
     60   return failed;
     61 }
     62 SANITIZER_WEAK_CXX_DEFAULT_IMPL
     63 void OnInitialize() {}
     64 #endif
     65 
     66 static char thread_registry_placeholder[sizeof(ThreadRegistry)];
     67 
     68 static ThreadContextBase *CreateThreadContext(u32 tid) {
     69   // Map thread trace when context is created.
     70   char name[50];
     71   internal_snprintf(name, sizeof(name), "trace %u", tid);
     72   MapThreadTrace(GetThreadTrace(tid), TraceSize() * sizeof(Event), name);
     73   const uptr hdr = GetThreadTraceHeader(tid);
     74   internal_snprintf(name, sizeof(name), "trace header %u", tid);
     75   MapThreadTrace(hdr, sizeof(Trace), name);
     76   new((void*)hdr) Trace();
     77   // We are going to use only a small part of the trace with the default
     78   // value of history_size. However, the constructor writes to the whole trace.
     79   // Unmap the unused part.
     80   uptr hdr_end = hdr + sizeof(Trace);
     81   hdr_end -= sizeof(TraceHeader) * (kTraceParts - TraceParts());
     82   hdr_end = RoundUp(hdr_end, GetPageSizeCached());
     83   if (hdr_end < hdr + sizeof(Trace))
     84     UnmapOrDie((void*)hdr_end, hdr + sizeof(Trace) - hdr_end);
     85   void *mem = internal_alloc(MBlockThreadContex, sizeof(ThreadContext));
     86   return new(mem) ThreadContext(tid);
     87 }
     88 
     89 #ifndef SANITIZER_GO
     90 static const u32 kThreadQuarantineSize = 16;
     91 #else
     92 static const u32 kThreadQuarantineSize = 64;
     93 #endif
     94 
     95 Context::Context()
     96   : initialized()
     97   , report_mtx(MutexTypeReport, StatMtxReport)
     98   , nreported()
     99   , nmissed_expected()
    100   , thread_registry(new(thread_registry_placeholder) ThreadRegistry(
    101       CreateThreadContext, kMaxTid, kThreadQuarantineSize, kMaxTidReuse))
    102   , racy_mtx(MutexTypeRacy, StatMtxRacy)
    103   , racy_stacks(MBlockRacyStacks)
    104   , racy_addresses(MBlockRacyAddresses)
    105   , fired_suppressions_mtx(MutexTypeFired, StatMtxFired)
    106   , fired_suppressions(8) {
    107 }
    108 
    109 // The objects are allocated in TLS, so one may rely on zero-initialization.
    110 ThreadState::ThreadState(Context *ctx, int tid, int unique_id, u64 epoch,
    111                          unsigned reuse_count,
    112                          uptr stk_addr, uptr stk_size,
    113                          uptr tls_addr, uptr tls_size)
    114   : fast_state(tid, epoch)
    115   // Do not touch these, rely on zero initialization,
    116   // they may be accessed before the ctor.
    117   // , ignore_reads_and_writes()
    118   // , ignore_interceptors()
    119   , clock(tid, reuse_count)
    120 #ifndef SANITIZER_GO
    121   , jmp_bufs(MBlockJmpBuf)
    122 #endif
    123   , tid(tid)
    124   , unique_id(unique_id)
    125   , stk_addr(stk_addr)
    126   , stk_size(stk_size)
    127   , tls_addr(tls_addr)
    128   , tls_size(tls_size)
    129 #ifndef SANITIZER_GO
    130   , last_sleep_clock(tid)
    131 #endif
    132 {
    133 }
    134 
    135 #ifndef SANITIZER_GO
    136 static void MemoryProfiler(Context *ctx, fd_t fd, int i) {
    137   uptr n_threads;
    138   uptr n_running_threads;
    139   ctx->thread_registry->GetNumberOfThreads(&n_threads, &n_running_threads);
    140   InternalScopedBuffer<char> buf(4096);
    141   WriteMemoryProfile(buf.data(), buf.size(), n_threads, n_running_threads);
    142   WriteToFile(fd, buf.data(), internal_strlen(buf.data()));
    143 }
    144 
    145 static void BackgroundThread(void *arg) {
    146   // This is a non-initialized non-user thread, nothing to see here.
    147   // We don't use ScopedIgnoreInterceptors, because we want ignores to be
    148   // enabled even when the thread function exits (e.g. during pthread thread
    149   // shutdown code).
    150   cur_thread()->ignore_interceptors++;
    151   const u64 kMs2Ns = 1000 * 1000;
    152 
    153   fd_t mprof_fd = kInvalidFd;
    154   if (flags()->profile_memory && flags()->profile_memory[0]) {
    155     if (internal_strcmp(flags()->profile_memory, "stdout") == 0) {
    156       mprof_fd = 1;
    157     } else if (internal_strcmp(flags()->profile_memory, "stderr") == 0) {
    158       mprof_fd = 2;
    159     } else {
    160       InternalScopedString filename(kMaxPathLength);
    161       filename.append("%s.%d", flags()->profile_memory, (int)internal_getpid());
    162       fd_t fd = OpenFile(filename.data(), WrOnly);
    163       if (fd == kInvalidFd) {
    164         Printf("ThreadSanitizer: failed to open memory profile file '%s'\n",
    165             &filename[0]);
    166       } else {
    167         mprof_fd = fd;
    168       }
    169     }
    170   }
    171 
    172   u64 last_flush = NanoTime();
    173   uptr last_rss = 0;
    174   for (int i = 0;
    175       atomic_load(&ctx->stop_background_thread, memory_order_relaxed) == 0;
    176       i++) {
    177     SleepForMillis(100);
    178     u64 now = NanoTime();
    179 
    180     // Flush memory if requested.
    181     if (flags()->flush_memory_ms > 0) {
    182       if (last_flush + flags()->flush_memory_ms * kMs2Ns < now) {
    183         VPrintf(1, "ThreadSanitizer: periodic memory flush\n");
    184         FlushShadowMemory();
    185         last_flush = NanoTime();
    186       }
    187     }
    188     // GetRSS can be expensive on huge programs, so don't do it every 100ms.
    189     if (flags()->memory_limit_mb > 0) {
    190       uptr rss = GetRSS();
    191       uptr limit = uptr(flags()->memory_limit_mb) << 20;
    192       VPrintf(1, "ThreadSanitizer: memory flush check"
    193                  " RSS=%llu LAST=%llu LIMIT=%llu\n",
    194               (u64)rss >> 20, (u64)last_rss >> 20, (u64)limit >> 20);
    195       if (2 * rss > limit + last_rss) {
    196         VPrintf(1, "ThreadSanitizer: flushing memory due to RSS\n");
    197         FlushShadowMemory();
    198         rss = GetRSS();
    199         VPrintf(1, "ThreadSanitizer: memory flushed RSS=%llu\n", (u64)rss>>20);
    200       }
    201       last_rss = rss;
    202     }
    203 
    204     // Write memory profile if requested.
    205     if (mprof_fd != kInvalidFd)
    206       MemoryProfiler(ctx, mprof_fd, i);
    207 
    208     // Flush symbolizer cache if requested.
    209     if (flags()->flush_symbolizer_ms > 0) {
    210       u64 last = atomic_load(&ctx->last_symbolize_time_ns,
    211                              memory_order_relaxed);
    212       if (last != 0 && last + flags()->flush_symbolizer_ms * kMs2Ns < now) {
    213         Lock l(&ctx->report_mtx);
    214         SpinMutexLock l2(&CommonSanitizerReportMutex);
    215         SymbolizeFlush();
    216         atomic_store(&ctx->last_symbolize_time_ns, 0, memory_order_relaxed);
    217       }
    218     }
    219   }
    220 }
    221 
    222 static void StartBackgroundThread() {
    223   ctx->background_thread = internal_start_thread(&BackgroundThread, 0);
    224 }
    225 
    226 #ifndef __mips__
    227 static void StopBackgroundThread() {
    228   atomic_store(&ctx->stop_background_thread, 1, memory_order_relaxed);
    229   internal_join_thread(ctx->background_thread);
    230   ctx->background_thread = 0;
    231 }
    232 #endif
    233 #endif
    234 
    235 void DontNeedShadowFor(uptr addr, uptr size) {
    236   uptr shadow_beg = MemToShadow(addr);
    237   uptr shadow_end = MemToShadow(addr + size);
    238   FlushUnneededShadowMemory(shadow_beg, shadow_end - shadow_beg);
    239 }
    240 
    241 void MapShadow(uptr addr, uptr size) {
    242   // Global data is not 64K aligned, but there are no adjacent mappings,
    243   // so we can get away with unaligned mapping.
    244   // CHECK_EQ(addr, addr & ~((64 << 10) - 1));  // windows wants 64K alignment
    245   MmapFixedNoReserve(MemToShadow(addr), size * kShadowMultiplier, "shadow");
    246 
    247   // Meta shadow is 2:1, so tread carefully.
    248   static bool data_mapped = false;
    249   static uptr mapped_meta_end = 0;
    250   uptr meta_begin = (uptr)MemToMeta(addr);
    251   uptr meta_end = (uptr)MemToMeta(addr + size);
    252   meta_begin = RoundDownTo(meta_begin, 64 << 10);
    253   meta_end = RoundUpTo(meta_end, 64 << 10);
    254   if (!data_mapped) {
    255     // First call maps data+bss.
    256     data_mapped = true;
    257     MmapFixedNoReserve(meta_begin, meta_end - meta_begin, "meta shadow");
    258   } else {
    259     // Mapping continous heap.
    260     // Windows wants 64K alignment.
    261     meta_begin = RoundDownTo(meta_begin, 64 << 10);
    262     meta_end = RoundUpTo(meta_end, 64 << 10);
    263     if (meta_end <= mapped_meta_end)
    264       return;
    265     if (meta_begin < mapped_meta_end)
    266       meta_begin = mapped_meta_end;
    267     MmapFixedNoReserve(meta_begin, meta_end - meta_begin, "meta shadow");
    268     mapped_meta_end = meta_end;
    269   }
    270   VPrintf(2, "mapped meta shadow for (%p-%p) at (%p-%p)\n",
    271       addr, addr+size, meta_begin, meta_end);
    272 }
    273 
    274 void MapThreadTrace(uptr addr, uptr size, const char *name) {
    275   DPrintf("#0: Mapping trace at %p-%p(0x%zx)\n", addr, addr + size, size);
    276   CHECK_GE(addr, TraceMemBeg());
    277   CHECK_LE(addr + size, TraceMemEnd());
    278   CHECK_EQ(addr, addr & ~((64 << 10) - 1));  // windows wants 64K alignment
    279   uptr addr1 = (uptr)MmapFixedNoReserve(addr, size, name);
    280   if (addr1 != addr) {
    281     Printf("FATAL: ThreadSanitizer can not mmap thread trace (%p/%p->%p)\n",
    282         addr, size, addr1);
    283     Die();
    284   }
    285 }
    286 
    287 static void CheckShadowMapping() {
    288   uptr beg, end;
    289   for (int i = 0; GetUserRegion(i, &beg, &end); i++) {
    290     VPrintf(3, "checking shadow region %p-%p\n", beg, end);
    291     for (uptr p0 = beg; p0 <= end; p0 += (end - beg) / 4) {
    292       for (int x = -1; x <= 1; x++) {
    293         const uptr p = p0 + x;
    294         if (p < beg || p >= end)
    295           continue;
    296         const uptr s = MemToShadow(p);
    297         const uptr m = (uptr)MemToMeta(p);
    298         VPrintf(3, "  checking pointer %p: shadow=%p meta=%p\n", p, s, m);
    299         CHECK(IsAppMem(p));
    300         CHECK(IsShadowMem(s));
    301         CHECK_EQ(p & ~(kShadowCell - 1), ShadowToMem(s));
    302         CHECK(IsMetaMem(m));
    303       }
    304     }
    305   }
    306 }
    307 
    308 void Initialize(ThreadState *thr) {
    309   // Thread safe because done before all threads exist.
    310   static bool is_initialized = false;
    311   if (is_initialized)
    312     return;
    313   is_initialized = true;
    314   // We are not ready to handle interceptors yet.
    315   ScopedIgnoreInterceptors ignore;
    316   SanitizerToolName = "ThreadSanitizer";
    317   // Install tool-specific callbacks in sanitizer_common.
    318   SetCheckFailedCallback(TsanCheckFailed);
    319 
    320   ctx = new(ctx_placeholder) Context;
    321   const char *options = GetEnv(kTsanOptionsEnv);
    322   CacheBinaryName();
    323   InitializeFlags(&ctx->flags, options);
    324   InitializePlatformEarly();
    325 #ifndef SANITIZER_GO
    326   // Re-exec ourselves if we need to set additional env or command line args.
    327   MaybeReexec();
    328 
    329   InitializeAllocator();
    330   ReplaceSystemMalloc();
    331 #endif
    332   InitializeInterceptors();
    333   CheckShadowMapping();
    334   InitializePlatform();
    335   InitializeMutex();
    336   InitializeDynamicAnnotations();
    337 #ifndef SANITIZER_GO
    338   InitializeShadowMemory();
    339 #endif
    340   // Setup correct file descriptor for error reports.
    341   __sanitizer_set_report_path(common_flags()->log_path);
    342   InitializeSuppressions();
    343 #ifndef SANITIZER_GO
    344   InitializeLibIgnore();
    345   Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer);
    346   // On MIPS, TSan initialization is run before
    347   // __pthread_initialize_minimal_internal() is finished, so we can not spawn
    348   // new threads.
    349 #ifndef __mips__
    350   StartBackgroundThread();
    351   SetSandboxingCallback(StopBackgroundThread);
    352 #endif
    353 #endif
    354   if (common_flags()->detect_deadlocks)
    355     ctx->dd = DDetector::Create(flags());
    356 
    357   VPrintf(1, "***** Running under ThreadSanitizer v2 (pid %d) *****\n",
    358           (int)internal_getpid());
    359 
    360   // Initialize thread 0.
    361   int tid = ThreadCreate(thr, 0, 0, true);
    362   CHECK_EQ(tid, 0);
    363   ThreadStart(thr, tid, internal_getpid());
    364 #if TSAN_CONTAINS_UBSAN
    365   __ubsan::InitAsPlugin();
    366 #endif
    367   ctx->initialized = true;
    368 
    369   if (flags()->stop_on_start) {
    370     Printf("ThreadSanitizer is suspended at startup (pid %d)."
    371            " Call __tsan_resume().\n",
    372            (int)internal_getpid());
    373     while (__tsan_resumed == 0) {}
    374   }
    375 
    376   OnInitialize();
    377 }
    378 
    379 int Finalize(ThreadState *thr) {
    380   bool failed = false;
    381 
    382   if (flags()->atexit_sleep_ms > 0 && ThreadCount(thr) > 1)
    383     SleepForMillis(flags()->atexit_sleep_ms);
    384 
    385   // Wait for pending reports.
    386   ctx->report_mtx.Lock();
    387   CommonSanitizerReportMutex.Lock();
    388   CommonSanitizerReportMutex.Unlock();
    389   ctx->report_mtx.Unlock();
    390 
    391 #ifndef SANITIZER_GO
    392   if (Verbosity()) AllocatorPrintStats();
    393 #endif
    394 
    395   ThreadFinalize(thr);
    396 
    397   if (ctx->nreported) {
    398     failed = true;
    399 #ifndef SANITIZER_GO
    400     Printf("ThreadSanitizer: reported %d warnings\n", ctx->nreported);
    401 #else
    402     Printf("Found %d data race(s)\n", ctx->nreported);
    403 #endif
    404   }
    405 
    406   if (ctx->nmissed_expected) {
    407     failed = true;
    408     Printf("ThreadSanitizer: missed %d expected races\n",
    409         ctx->nmissed_expected);
    410   }
    411 
    412   if (common_flags()->print_suppressions)
    413     PrintMatchedSuppressions();
    414 #ifndef SANITIZER_GO
    415   if (flags()->print_benign)
    416     PrintMatchedBenignRaces();
    417 #endif
    418 
    419   failed = OnFinalize(failed);
    420 
    421 #if TSAN_COLLECT_STATS
    422   StatAggregate(ctx->stat, thr->stat);
    423   StatOutput(ctx->stat);
    424 #endif
    425 
    426   return failed ? common_flags()->exitcode : 0;
    427 }
    428 
    429 #ifndef SANITIZER_GO
    430 void ForkBefore(ThreadState *thr, uptr pc) {
    431   ctx->thread_registry->Lock();
    432   ctx->report_mtx.Lock();
    433 }
    434 
    435 void ForkParentAfter(ThreadState *thr, uptr pc) {
    436   ctx->report_mtx.Unlock();
    437   ctx->thread_registry->Unlock();
    438 }
    439 
    440 void ForkChildAfter(ThreadState *thr, uptr pc) {
    441   ctx->report_mtx.Unlock();
    442   ctx->thread_registry->Unlock();
    443 
    444   uptr nthread = 0;
    445   ctx->thread_registry->GetNumberOfThreads(0, 0, &nthread /* alive threads */);
    446   VPrintf(1, "ThreadSanitizer: forked new process with pid %d,"
    447       " parent had %d threads\n", (int)internal_getpid(), (int)nthread);
    448   if (nthread == 1) {
    449     StartBackgroundThread();
    450   } else {
    451     // We've just forked a multi-threaded process. We cannot reasonably function
    452     // after that (some mutexes may be locked before fork). So just enable
    453     // ignores for everything in the hope that we will exec soon.
    454     ctx->after_multithreaded_fork = true;
    455     thr->ignore_interceptors++;
    456     ThreadIgnoreBegin(thr, pc);
    457     ThreadIgnoreSyncBegin(thr, pc);
    458   }
    459 }
    460 #endif
    461 
    462 #ifdef SANITIZER_GO
    463 NOINLINE
    464 void GrowShadowStack(ThreadState *thr) {
    465   const int sz = thr->shadow_stack_end - thr->shadow_stack;
    466   const int newsz = 2 * sz;
    467   uptr *newstack = (uptr*)internal_alloc(MBlockShadowStack,
    468       newsz * sizeof(uptr));
    469   internal_memcpy(newstack, thr->shadow_stack, sz * sizeof(uptr));
    470   internal_free(thr->shadow_stack);
    471   thr->shadow_stack = newstack;
    472   thr->shadow_stack_pos = newstack + sz;
    473   thr->shadow_stack_end = newstack + newsz;
    474 }
    475 #endif
    476 
    477 u32 CurrentStackId(ThreadState *thr, uptr pc) {
    478   if (!thr->is_inited)  // May happen during bootstrap.
    479     return 0;
    480   if (pc != 0) {
    481 #ifndef SANITIZER_GO
    482     DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
    483 #else
    484     if (thr->shadow_stack_pos == thr->shadow_stack_end)
    485       GrowShadowStack(thr);
    486 #endif
    487     thr->shadow_stack_pos[0] = pc;
    488     thr->shadow_stack_pos++;
    489   }
    490   u32 id = StackDepotPut(
    491       StackTrace(thr->shadow_stack, thr->shadow_stack_pos - thr->shadow_stack));
    492   if (pc != 0)
    493     thr->shadow_stack_pos--;
    494   return id;
    495 }
    496 
    497 void TraceSwitch(ThreadState *thr) {
    498   thr->nomalloc++;
    499   Trace *thr_trace = ThreadTrace(thr->tid);
    500   Lock l(&thr_trace->mtx);
    501   unsigned trace = (thr->fast_state.epoch() / kTracePartSize) % TraceParts();
    502   TraceHeader *hdr = &thr_trace->headers[trace];
    503   hdr->epoch0 = thr->fast_state.epoch();
    504   ObtainCurrentStack(thr, 0, &hdr->stack0);
    505   hdr->mset0 = thr->mset;
    506   thr->nomalloc--;
    507 }
    508 
    509 Trace *ThreadTrace(int tid) {
    510   return (Trace*)GetThreadTraceHeader(tid);
    511 }
    512 
    513 uptr TraceTopPC(ThreadState *thr) {
    514   Event *events = (Event*)GetThreadTrace(thr->tid);
    515   uptr pc = events[thr->fast_state.GetTracePos()];
    516   return pc;
    517 }
    518 
    519 uptr TraceSize() {
    520   return (uptr)(1ull << (kTracePartSizeBits + flags()->history_size + 1));
    521 }
    522 
    523 uptr TraceParts() {
    524   return TraceSize() / kTracePartSize;
    525 }
    526 
    527 #ifndef SANITIZER_GO
    528 extern "C" void __tsan_trace_switch() {
    529   TraceSwitch(cur_thread());
    530 }
    531 
    532 extern "C" void __tsan_report_race() {
    533   ReportRace(cur_thread());
    534 }
    535 #endif
    536 
    537 ALWAYS_INLINE
    538 Shadow LoadShadow(u64 *p) {
    539   u64 raw = atomic_load((atomic_uint64_t*)p, memory_order_relaxed);
    540   return Shadow(raw);
    541 }
    542 
    543 ALWAYS_INLINE
    544 void StoreShadow(u64 *sp, u64 s) {
    545   atomic_store((atomic_uint64_t*)sp, s, memory_order_relaxed);
    546 }
    547 
    548 ALWAYS_INLINE
    549 void StoreIfNotYetStored(u64 *sp, u64 *s) {
    550   StoreShadow(sp, *s);
    551   *s = 0;
    552 }
    553 
    554 ALWAYS_INLINE
    555 void HandleRace(ThreadState *thr, u64 *shadow_mem,
    556                               Shadow cur, Shadow old) {
    557   thr->racy_state[0] = cur.raw();
    558   thr->racy_state[1] = old.raw();
    559   thr->racy_shadow_addr = shadow_mem;
    560 #ifndef SANITIZER_GO
    561   HACKY_CALL(__tsan_report_race);
    562 #else
    563   ReportRace(thr);
    564 #endif
    565 }
    566 
    567 static inline bool HappensBefore(Shadow old, ThreadState *thr) {
    568   return thr->clock.get(old.TidWithIgnore()) >= old.epoch();
    569 }
    570 
    571 ALWAYS_INLINE
    572 void MemoryAccessImpl1(ThreadState *thr, uptr addr,
    573     int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic,
    574     u64 *shadow_mem, Shadow cur) {
    575   StatInc(thr, StatMop);
    576   StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    577   StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    578 
    579   // This potentially can live in an MMX/SSE scratch register.
    580   // The required intrinsics are:
    581   // __m128i _mm_move_epi64(__m128i*);
    582   // _mm_storel_epi64(u64*, __m128i);
    583   u64 store_word = cur.raw();
    584 
    585   // scan all the shadow values and dispatch to 4 categories:
    586   // same, replace, candidate and race (see comments below).
    587   // we consider only 3 cases regarding access sizes:
    588   // equal, intersect and not intersect. initially I considered
    589   // larger and smaller as well, it allowed to replace some
    590   // 'candidates' with 'same' or 'replace', but I think
    591   // it's just not worth it (performance- and complexity-wise).
    592 
    593   Shadow old(0);
    594 
    595   // It release mode we manually unroll the loop,
    596   // because empirically gcc generates better code this way.
    597   // However, we can't afford unrolling in debug mode, because the function
    598   // consumes almost 4K of stack. Gtest gives only 4K of stack to death test
    599   // threads, which is not enough for the unrolled loop.
    600 #if SANITIZER_DEBUG
    601   for (int idx = 0; idx < 4; idx++) {
    602 #include "tsan_update_shadow_word_inl.h"
    603   }
    604 #else
    605   int idx = 0;
    606 #include "tsan_update_shadow_word_inl.h"
    607   idx = 1;
    608 #include "tsan_update_shadow_word_inl.h"
    609   idx = 2;
    610 #include "tsan_update_shadow_word_inl.h"
    611   idx = 3;
    612 #include "tsan_update_shadow_word_inl.h"
    613 #endif
    614 
    615   // we did not find any races and had already stored
    616   // the current access info, so we are done
    617   if (LIKELY(store_word == 0))
    618     return;
    619   // choose a random candidate slot and replace it
    620   StoreShadow(shadow_mem + (cur.epoch() % kShadowCnt), store_word);
    621   StatInc(thr, StatShadowReplace);
    622   return;
    623  RACE:
    624   HandleRace(thr, shadow_mem, cur, old);
    625   return;
    626 }
    627 
    628 void UnalignedMemoryAccess(ThreadState *thr, uptr pc, uptr addr,
    629     int size, bool kAccessIsWrite, bool kIsAtomic) {
    630   while (size) {
    631     int size1 = 1;
    632     int kAccessSizeLog = kSizeLog1;
    633     if (size >= 8 && (addr & ~7) == ((addr + 7) & ~7)) {
    634       size1 = 8;
    635       kAccessSizeLog = kSizeLog8;
    636     } else if (size >= 4 && (addr & ~7) == ((addr + 3) & ~7)) {
    637       size1 = 4;
    638       kAccessSizeLog = kSizeLog4;
    639     } else if (size >= 2 && (addr & ~7) == ((addr + 1) & ~7)) {
    640       size1 = 2;
    641       kAccessSizeLog = kSizeLog2;
    642     }
    643     MemoryAccess(thr, pc, addr, kAccessSizeLog, kAccessIsWrite, kIsAtomic);
    644     addr += size1;
    645     size -= size1;
    646   }
    647 }
    648 
    649 ALWAYS_INLINE
    650 bool ContainsSameAccessSlow(u64 *s, u64 a, u64 sync_epoch, bool is_write) {
    651   Shadow cur(a);
    652   for (uptr i = 0; i < kShadowCnt; i++) {
    653     Shadow old(LoadShadow(&s[i]));
    654     if (Shadow::Addr0AndSizeAreEqual(cur, old) &&
    655         old.TidWithIgnore() == cur.TidWithIgnore() &&
    656         old.epoch() > sync_epoch &&
    657         old.IsAtomic() == cur.IsAtomic() &&
    658         old.IsRead() <= cur.IsRead())
    659       return true;
    660   }
    661   return false;
    662 }
    663 
    664 #if defined(__SSE3__)
    665 #define SHUF(v0, v1, i0, i1, i2, i3) _mm_castps_si128(_mm_shuffle_ps( \
    666     _mm_castsi128_ps(v0), _mm_castsi128_ps(v1), \
    667     (i0)*1 + (i1)*4 + (i2)*16 + (i3)*64))
    668 ALWAYS_INLINE
    669 bool ContainsSameAccessFast(u64 *s, u64 a, u64 sync_epoch, bool is_write) {
    670   // This is an optimized version of ContainsSameAccessSlow.
    671   // load current access into access[0:63]
    672   const m128 access     = _mm_cvtsi64_si128(a);
    673   // duplicate high part of access in addr0:
    674   // addr0[0:31]        = access[32:63]
    675   // addr0[32:63]       = access[32:63]
    676   // addr0[64:95]       = access[32:63]
    677   // addr0[96:127]      = access[32:63]
    678   const m128 addr0      = SHUF(access, access, 1, 1, 1, 1);
    679   // load 4 shadow slots
    680   const m128 shadow0    = _mm_load_si128((__m128i*)s);
    681   const m128 shadow1    = _mm_load_si128((__m128i*)s + 1);
    682   // load high parts of 4 shadow slots into addr_vect:
    683   // addr_vect[0:31]    = shadow0[32:63]
    684   // addr_vect[32:63]   = shadow0[96:127]
    685   // addr_vect[64:95]   = shadow1[32:63]
    686   // addr_vect[96:127]  = shadow1[96:127]
    687   m128 addr_vect        = SHUF(shadow0, shadow1, 1, 3, 1, 3);
    688   if (!is_write) {
    689     // set IsRead bit in addr_vect
    690     const m128 rw_mask1 = _mm_cvtsi64_si128(1<<15);
    691     const m128 rw_mask  = SHUF(rw_mask1, rw_mask1, 0, 0, 0, 0);
    692     addr_vect           = _mm_or_si128(addr_vect, rw_mask);
    693   }
    694   // addr0 == addr_vect?
    695   const m128 addr_res   = _mm_cmpeq_epi32(addr0, addr_vect);
    696   // epoch1[0:63]       = sync_epoch
    697   const m128 epoch1     = _mm_cvtsi64_si128(sync_epoch);
    698   // epoch[0:31]        = sync_epoch[0:31]
    699   // epoch[32:63]       = sync_epoch[0:31]
    700   // epoch[64:95]       = sync_epoch[0:31]
    701   // epoch[96:127]      = sync_epoch[0:31]
    702   const m128 epoch      = SHUF(epoch1, epoch1, 0, 0, 0, 0);
    703   // load low parts of shadow cell epochs into epoch_vect:
    704   // epoch_vect[0:31]   = shadow0[0:31]
    705   // epoch_vect[32:63]  = shadow0[64:95]
    706   // epoch_vect[64:95]  = shadow1[0:31]
    707   // epoch_vect[96:127] = shadow1[64:95]
    708   const m128 epoch_vect = SHUF(shadow0, shadow1, 0, 2, 0, 2);
    709   // epoch_vect >= sync_epoch?
    710   const m128 epoch_res  = _mm_cmpgt_epi32(epoch_vect, epoch);
    711   // addr_res & epoch_res
    712   const m128 res        = _mm_and_si128(addr_res, epoch_res);
    713   // mask[0] = res[7]
    714   // mask[1] = res[15]
    715   // ...
    716   // mask[15] = res[127]
    717   const int mask        = _mm_movemask_epi8(res);
    718   return mask != 0;
    719 }
    720 #endif
    721 
    722 ALWAYS_INLINE
    723 bool ContainsSameAccess(u64 *s, u64 a, u64 sync_epoch, bool is_write) {
    724 #if defined(__SSE3__)
    725   bool res = ContainsSameAccessFast(s, a, sync_epoch, is_write);
    726   // NOTE: this check can fail if the shadow is concurrently mutated
    727   // by other threads. But it still can be useful if you modify
    728   // ContainsSameAccessFast and want to ensure that it's not completely broken.
    729   // DCHECK_EQ(res, ContainsSameAccessSlow(s, a, sync_epoch, is_write));
    730   return res;
    731 #else
    732   return ContainsSameAccessSlow(s, a, sync_epoch, is_write);
    733 #endif
    734 }
    735 
    736 ALWAYS_INLINE USED
    737 void MemoryAccess(ThreadState *thr, uptr pc, uptr addr,
    738     int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic) {
    739   u64 *shadow_mem = (u64*)MemToShadow(addr);
    740   DPrintf2("#%d: MemoryAccess: @%p %p size=%d"
    741       " is_write=%d shadow_mem=%p {%zx, %zx, %zx, %zx}\n",
    742       (int)thr->fast_state.tid(), (void*)pc, (void*)addr,
    743       (int)(1 << kAccessSizeLog), kAccessIsWrite, shadow_mem,
    744       (uptr)shadow_mem[0], (uptr)shadow_mem[1],
    745       (uptr)shadow_mem[2], (uptr)shadow_mem[3]);
    746 #if SANITIZER_DEBUG
    747   if (!IsAppMem(addr)) {
    748     Printf("Access to non app mem %zx\n", addr);
    749     DCHECK(IsAppMem(addr));
    750   }
    751   if (!IsShadowMem((uptr)shadow_mem)) {
    752     Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
    753     DCHECK(IsShadowMem((uptr)shadow_mem));
    754   }
    755 #endif
    756 
    757   if (kCppMode && *shadow_mem == kShadowRodata) {
    758     // Access to .rodata section, no races here.
    759     // Measurements show that it can be 10-20% of all memory accesses.
    760     StatInc(thr, StatMop);
    761     StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    762     StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    763     StatInc(thr, StatMopRodata);
    764     return;
    765   }
    766 
    767   FastState fast_state = thr->fast_state;
    768   if (fast_state.GetIgnoreBit()) {
    769     StatInc(thr, StatMop);
    770     StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    771     StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    772     StatInc(thr, StatMopIgnored);
    773     return;
    774   }
    775 
    776   Shadow cur(fast_state);
    777   cur.SetAddr0AndSizeLog(addr & 7, kAccessSizeLog);
    778   cur.SetWrite(kAccessIsWrite);
    779   cur.SetAtomic(kIsAtomic);
    780 
    781   if (LIKELY(ContainsSameAccess(shadow_mem, cur.raw(),
    782       thr->fast_synch_epoch, kAccessIsWrite))) {
    783     StatInc(thr, StatMop);
    784     StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    785     StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    786     StatInc(thr, StatMopSame);
    787     return;
    788   }
    789 
    790   if (kCollectHistory) {
    791     fast_state.IncrementEpoch();
    792     thr->fast_state = fast_state;
    793     TraceAddEvent(thr, fast_state, EventTypeMop, pc);
    794     cur.IncrementEpoch();
    795   }
    796 
    797   MemoryAccessImpl1(thr, addr, kAccessSizeLog, kAccessIsWrite, kIsAtomic,
    798       shadow_mem, cur);
    799 }
    800 
    801 // Called by MemoryAccessRange in tsan_rtl_thread.cc
    802 ALWAYS_INLINE USED
    803 void MemoryAccessImpl(ThreadState *thr, uptr addr,
    804     int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic,
    805     u64 *shadow_mem, Shadow cur) {
    806   if (LIKELY(ContainsSameAccess(shadow_mem, cur.raw(),
    807       thr->fast_synch_epoch, kAccessIsWrite))) {
    808     StatInc(thr, StatMop);
    809     StatInc(thr, kAccessIsWrite ? StatMopWrite : StatMopRead);
    810     StatInc(thr, (StatType)(StatMop1 + kAccessSizeLog));
    811     StatInc(thr, StatMopSame);
    812     return;
    813   }
    814 
    815   MemoryAccessImpl1(thr, addr, kAccessSizeLog, kAccessIsWrite, kIsAtomic,
    816       shadow_mem, cur);
    817 }
    818 
    819 static void MemoryRangeSet(ThreadState *thr, uptr pc, uptr addr, uptr size,
    820                            u64 val) {
    821   (void)thr;
    822   (void)pc;
    823   if (size == 0)
    824     return;
    825   // FIXME: fix me.
    826   uptr offset = addr % kShadowCell;
    827   if (offset) {
    828     offset = kShadowCell - offset;
    829     if (size <= offset)
    830       return;
    831     addr += offset;
    832     size -= offset;
    833   }
    834   DCHECK_EQ(addr % 8, 0);
    835   // If a user passes some insane arguments (memset(0)),
    836   // let it just crash as usual.
    837   if (!IsAppMem(addr) || !IsAppMem(addr + size - 1))
    838     return;
    839   // Don't want to touch lots of shadow memory.
    840   // If a program maps 10MB stack, there is no need reset the whole range.
    841   size = (size + (kShadowCell - 1)) & ~(kShadowCell - 1);
    842   // UnmapOrDie/MmapFixedNoReserve does not work on Windows,
    843   // so we do it only for C/C++.
    844   if (kGoMode || size < common_flags()->clear_shadow_mmap_threshold) {
    845     u64 *p = (u64*)MemToShadow(addr);
    846     CHECK(IsShadowMem((uptr)p));
    847     CHECK(IsShadowMem((uptr)(p + size * kShadowCnt / kShadowCell - 1)));
    848     // FIXME: may overwrite a part outside the region
    849     for (uptr i = 0; i < size / kShadowCell * kShadowCnt;) {
    850       p[i++] = val;
    851       for (uptr j = 1; j < kShadowCnt; j++)
    852         p[i++] = 0;
    853     }
    854   } else {
    855     // The region is big, reset only beginning and end.
    856     const uptr kPageSize = GetPageSizeCached();
    857     u64 *begin = (u64*)MemToShadow(addr);
    858     u64 *end = begin + size / kShadowCell * kShadowCnt;
    859     u64 *p = begin;
    860     // Set at least first kPageSize/2 to page boundary.
    861     while ((p < begin + kPageSize / kShadowSize / 2) || ((uptr)p % kPageSize)) {
    862       *p++ = val;
    863       for (uptr j = 1; j < kShadowCnt; j++)
    864         *p++ = 0;
    865     }
    866     // Reset middle part.
    867     u64 *p1 = p;
    868     p = RoundDown(end, kPageSize);
    869     UnmapOrDie((void*)p1, (uptr)p - (uptr)p1);
    870     MmapFixedNoReserve((uptr)p1, (uptr)p - (uptr)p1);
    871     // Set the ending.
    872     while (p < end) {
    873       *p++ = val;
    874       for (uptr j = 1; j < kShadowCnt; j++)
    875         *p++ = 0;
    876     }
    877   }
    878 }
    879 
    880 void MemoryResetRange(ThreadState *thr, uptr pc, uptr addr, uptr size) {
    881   MemoryRangeSet(thr, pc, addr, size, 0);
    882 }
    883 
    884 void MemoryRangeFreed(ThreadState *thr, uptr pc, uptr addr, uptr size) {
    885   // Processing more than 1k (4k of shadow) is expensive,
    886   // can cause excessive memory consumption (user does not necessary touch
    887   // the whole range) and most likely unnecessary.
    888   if (size > 1024)
    889     size = 1024;
    890   CHECK_EQ(thr->is_freeing, false);
    891   thr->is_freeing = true;
    892   MemoryAccessRange(thr, pc, addr, size, true);
    893   thr->is_freeing = false;
    894   if (kCollectHistory) {
    895     thr->fast_state.IncrementEpoch();
    896     TraceAddEvent(thr, thr->fast_state, EventTypeMop, pc);
    897   }
    898   Shadow s(thr->fast_state);
    899   s.ClearIgnoreBit();
    900   s.MarkAsFreed();
    901   s.SetWrite(true);
    902   s.SetAddr0AndSizeLog(0, 3);
    903   MemoryRangeSet(thr, pc, addr, size, s.raw());
    904 }
    905 
    906 void MemoryRangeImitateWrite(ThreadState *thr, uptr pc, uptr addr, uptr size) {
    907   if (kCollectHistory) {
    908     thr->fast_state.IncrementEpoch();
    909     TraceAddEvent(thr, thr->fast_state, EventTypeMop, pc);
    910   }
    911   Shadow s(thr->fast_state);
    912   s.ClearIgnoreBit();
    913   s.SetWrite(true);
    914   s.SetAddr0AndSizeLog(0, 3);
    915   MemoryRangeSet(thr, pc, addr, size, s.raw());
    916 }
    917 
    918 ALWAYS_INLINE USED
    919 void FuncEntry(ThreadState *thr, uptr pc) {
    920   StatInc(thr, StatFuncEnter);
    921   DPrintf2("#%d: FuncEntry %p\n", (int)thr->fast_state.tid(), (void*)pc);
    922   if (kCollectHistory) {
    923     thr->fast_state.IncrementEpoch();
    924     TraceAddEvent(thr, thr->fast_state, EventTypeFuncEnter, pc);
    925   }
    926 
    927   // Shadow stack maintenance can be replaced with
    928   // stack unwinding during trace switch (which presumably must be faster).
    929   DCHECK_GE(thr->shadow_stack_pos, thr->shadow_stack);
    930 #ifndef SANITIZER_GO
    931   DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
    932 #else
    933   if (thr->shadow_stack_pos == thr->shadow_stack_end)
    934     GrowShadowStack(thr);
    935 #endif
    936   thr->shadow_stack_pos[0] = pc;
    937   thr->shadow_stack_pos++;
    938 }
    939 
    940 ALWAYS_INLINE USED
    941 void FuncExit(ThreadState *thr) {
    942   StatInc(thr, StatFuncExit);
    943   DPrintf2("#%d: FuncExit\n", (int)thr->fast_state.tid());
    944   if (kCollectHistory) {
    945     thr->fast_state.IncrementEpoch();
    946     TraceAddEvent(thr, thr->fast_state, EventTypeFuncExit, 0);
    947   }
    948 
    949   DCHECK_GT(thr->shadow_stack_pos, thr->shadow_stack);
    950 #ifndef SANITIZER_GO
    951   DCHECK_LT(thr->shadow_stack_pos, thr->shadow_stack_end);
    952 #endif
    953   thr->shadow_stack_pos--;
    954 }
    955 
    956 void ThreadIgnoreBegin(ThreadState *thr, uptr pc) {
    957   DPrintf("#%d: ThreadIgnoreBegin\n", thr->tid);
    958   thr->ignore_reads_and_writes++;
    959   CHECK_GT(thr->ignore_reads_and_writes, 0);
    960   thr->fast_state.SetIgnoreBit();
    961 #ifndef SANITIZER_GO
    962   if (!ctx->after_multithreaded_fork)
    963     thr->mop_ignore_set.Add(CurrentStackId(thr, pc));
    964 #endif
    965 }
    966 
    967 void ThreadIgnoreEnd(ThreadState *thr, uptr pc) {
    968   DPrintf("#%d: ThreadIgnoreEnd\n", thr->tid);
    969   thr->ignore_reads_and_writes--;
    970   CHECK_GE(thr->ignore_reads_and_writes, 0);
    971   if (thr->ignore_reads_and_writes == 0) {
    972     thr->fast_state.ClearIgnoreBit();
    973 #ifndef SANITIZER_GO
    974     thr->mop_ignore_set.Reset();
    975 #endif
    976   }
    977 }
    978 
    979 void ThreadIgnoreSyncBegin(ThreadState *thr, uptr pc) {
    980   DPrintf("#%d: ThreadIgnoreSyncBegin\n", thr->tid);
    981   thr->ignore_sync++;
    982   CHECK_GT(thr->ignore_sync, 0);
    983 #ifndef SANITIZER_GO
    984   if (!ctx->after_multithreaded_fork)
    985     thr->sync_ignore_set.Add(CurrentStackId(thr, pc));
    986 #endif
    987 }
    988 
    989 void ThreadIgnoreSyncEnd(ThreadState *thr, uptr pc) {
    990   DPrintf("#%d: ThreadIgnoreSyncEnd\n", thr->tid);
    991   thr->ignore_sync--;
    992   CHECK_GE(thr->ignore_sync, 0);
    993 #ifndef SANITIZER_GO
    994   if (thr->ignore_sync == 0)
    995     thr->sync_ignore_set.Reset();
    996 #endif
    997 }
    998 
    999 bool MD5Hash::operator==(const MD5Hash &other) const {
   1000   return hash[0] == other.hash[0] && hash[1] == other.hash[1];
   1001 }
   1002 
   1003 #if SANITIZER_DEBUG
   1004 void build_consistency_debug() {}
   1005 #else
   1006 void build_consistency_release() {}
   1007 #endif
   1008 
   1009 #if TSAN_COLLECT_STATS
   1010 void build_consistency_stats() {}
   1011 #else
   1012 void build_consistency_nostats() {}
   1013 #endif
   1014 
   1015 }  // namespace __tsan
   1016 
   1017 #ifndef SANITIZER_GO
   1018 // Must be included in this file to make sure everything is inlined.
   1019 #include "tsan_interface_inl.h"
   1020 #endif
   1021