libsanitizer/tsan/tsan_rtl_thread.cc - gcc - Git at Google

 //===-- tsan_rtl_thread.cc ------------------------------------------------===//
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of ThreadSanitizer (TSan), a race detector.
 //
 //===----------------------------------------------------------------------===//

 #include "sanitizer_common/sanitizer_placement_new.h"
 #include "tsan_rtl.h"
 #include "tsan_mman.h"
 #include "tsan_platform.h"
 #include "tsan_report.h"
 #include "tsan_sync.h"

 namespace __tsan {

 // ThreadContext implementation.

 ThreadContext::ThreadContext(int tid)
   : ThreadContextBase(tid)
   , thr()
   , sync()
   , epoch0()
   , epoch1() {
 }

 #if !SANITIZER_GO
 ThreadContext::~ThreadContext() {
 }
 #endif

 void ThreadContext::OnDead() {
   CHECK_EQ(sync.size(), 0);
 }

 void ThreadContext::OnJoined(void *arg) {
   ThreadState *caller_thr = static_cast<ThreadState *>(arg);
   AcquireImpl(caller_thr, 0, &sync);
   sync.Reset(&caller_thr->proc()->clock_cache);
 }

 struct OnCreatedArgs {
   ThreadState *thr;
   uptr pc;
 };

 void ThreadContext::OnCreated(void *arg) {
   thr = 0;
   if (tid == 0)
     return;
   OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
   if (!args->thr)  // GCD workers don't have a parent thread.
     return;
   args->thr->fast_state.IncrementEpoch();
   // Can't increment epoch w/o writing to the trace as well.
   TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
   ReleaseImpl(args->thr, 0, &sync);
   creation_stack_id = CurrentStackId(args->thr, args->pc);
   if (reuse_count == 0)
     StatInc(args->thr, StatThreadMaxTid);
 }

 void ThreadContext::OnReset() {
   CHECK_EQ(sync.size(), 0);
   uptr trace_p = GetThreadTrace(tid);
   ReleaseMemoryPagesToOS(trace_p, trace_p + TraceSize() * sizeof(Event));
   //!!! ReleaseMemoryToOS(GetThreadTraceHeader(tid), sizeof(Trace));
 }

 void ThreadContext::OnDetached(void *arg) {
   ThreadState *thr1 = static_cast<ThreadState*>(arg);
   sync.Reset(&thr1->proc()->clock_cache);
 }

 struct OnStartedArgs {
   ThreadState *thr;
   uptr stk_addr;
   uptr stk_size;
   uptr tls_addr;
   uptr tls_size;
 };

 void ThreadContext::OnStarted(void *arg) {
   OnStartedArgs *args = static_cast<OnStartedArgs*>(arg);
   thr = args->thr;
   // RoundUp so that one trace part does not contain events
   // from different threads.
   epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
   epoch1 = (u64)-1;
   new(thr) ThreadState(ctx, tid, unique_id, epoch0, reuse_count,
       args->stk_addr, args->stk_size, args->tls_addr, args->tls_size);
 #if !SANITIZER_GO
   thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
   thr->shadow_stack_pos = thr->shadow_stack;
   thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
 #else
   // Setup dynamic shadow stack.
   const int kInitStackSize = 8;
   thr->shadow_stack = (uptr*)internal_alloc(MBlockShadowStack,
       kInitStackSize * sizeof(uptr));
   thr->shadow_stack_pos = thr->shadow_stack;
   thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
 #endif
   if (common_flags()->detect_deadlocks)
     thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
   thr->fast_state.SetHistorySize(flags()->history_size);
   // Commit switch to the new part of the trace.
   // TraceAddEvent will reset stack0/mset0 in the new part for us.
   TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);

   thr->fast_synch_epoch = epoch0;
   AcquireImpl(thr, 0, &sync);
   StatInc(thr, StatSyncAcquire);
   sync.Reset(&thr->proc()->clock_cache);
   thr->is_inited = true;
   DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
           "tls_addr=%zx tls_size=%zx\n",
           tid, (uptr)epoch0, args->stk_addr, args->stk_size,
           args->tls_addr, args->tls_size);
 }

 void ThreadContext::OnFinished() {
 #if SANITIZER_GO
   internal_free(thr->shadow_stack);
   thr->shadow_stack = nullptr;
   thr->shadow_stack_pos = nullptr;
   thr->shadow_stack_end = nullptr;
 #endif
   if (!detached) {
     thr->fast_state.IncrementEpoch();
     // Can't increment epoch w/o writing to the trace as well.
     TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
     ReleaseImpl(thr, 0, &sync);
   }
   epoch1 = thr->fast_state.epoch();

   if (common_flags()->detect_deadlocks)
     ctx->dd->DestroyLogicalThread(thr->dd_lt);
   thr->clock.ResetCached(&thr->proc()->clock_cache);
 #if !SANITIZER_GO
   thr->last_sleep_clock.ResetCached(&thr->proc()->clock_cache);
 #endif
   thr->~ThreadState();
 #if TSAN_COLLECT_STATS
   StatAggregate(ctx->stat, thr->stat);
 #endif
   thr = 0;
 }

 #if !SANITIZER_GO
 struct ThreadLeak {
   ThreadContext *tctx;
   int count;
 };

 static void MaybeReportThreadLeak(ThreadContextBase *tctx_base, void *arg) {
   Vector<ThreadLeak> &leaks = *(Vector<ThreadLeak>*)arg;
   ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
   if (tctx->detached || tctx->status != ThreadStatusFinished)
     return;
   for (uptr i = 0; i < leaks.Size(); i++) {
     if (leaks[i].tctx->creation_stack_id == tctx->creation_stack_id) {
       leaks[i].count++;
       return;
     }
   }
   ThreadLeak leak = {tctx, 1};
   leaks.PushBack(leak);
 }
 #endif

 #if !SANITIZER_GO
 static void ReportIgnoresEnabled(ThreadContext *tctx, IgnoreSet *set) {
   if (tctx->tid == 0) {
     Printf("ThreadSanitizer: main thread finished with ignores enabled\n");
   } else {
     Printf("ThreadSanitizer: thread T%d %s finished with ignores enabled,"
       " created at:\n", tctx->tid, tctx->name);
     PrintStack(SymbolizeStackId(tctx->creation_stack_id));
   }
   Printf("  One of the following ignores was not ended"
       " (in order of probability)\n");
   for (uptr i = 0; i < set->Size(); i++) {
     Printf("  Ignore was enabled at:\n");
     PrintStack(SymbolizeStackId(set->At(i)));
   }
   Die();
 }

 static void ThreadCheckIgnore(ThreadState *thr) {
   if (ctx->after_multithreaded_fork)
     return;
   if (thr->ignore_reads_and_writes)
     ReportIgnoresEnabled(thr->tctx, &thr->mop_ignore_set);
   if (thr->ignore_sync)
     ReportIgnoresEnabled(thr->tctx, &thr->sync_ignore_set);
 }
 #else
 static void ThreadCheckIgnore(ThreadState *thr) {}
 #endif

 void ThreadFinalize(ThreadState *thr) {
   ThreadCheckIgnore(thr);
 #if !SANITIZER_GO
   if (!flags()->report_thread_leaks)
     return;
   ThreadRegistryLock l(ctx->thread_registry);
   Vector<ThreadLeak> leaks(MBlockScopedBuf);
   ctx->thread_registry->RunCallbackForEachThreadLocked(
       MaybeReportThreadLeak, &leaks);
   for (uptr i = 0; i < leaks.Size(); i++) {
     ScopedReport rep(ReportTypeThreadLeak);
     rep.AddThread(leaks[i].tctx, true);
     rep.SetCount(leaks[i].count);
     OutputReport(thr, rep);
   }
 #endif
 }

 int ThreadCount(ThreadState *thr) {
   uptr result;
   ctx->thread_registry->GetNumberOfThreads(0, 0, &result);
   return (int)result;
 }

 int ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
   StatInc(thr, StatThreadCreate);
   OnCreatedArgs args = { thr, pc };
   u32 parent_tid = thr ? thr->tid : kInvalidTid;  // No parent for GCD workers.
   int tid =
       ctx->thread_registry->CreateThread(uid, detached, parent_tid, &args);
   DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", parent_tid, tid, uid);
   StatSet(thr, StatThreadMaxAlive, ctx->thread_registry->GetMaxAliveThreads());
   return tid;
 }

 void ThreadStart(ThreadState *thr, int tid, tid_t os_id, bool workerthread) {
   uptr stk_addr = 0;
   uptr stk_size = 0;
   uptr tls_addr = 0;
   uptr tls_size = 0;
 #if !SANITIZER_GO
   GetThreadStackAndTls(tid == 0, &stk_addr, &stk_size, &tls_addr, &tls_size);

   if (tid) {
     if (stk_addr && stk_size)
       MemoryRangeImitateWrite(thr, /*pc=*/ 1, stk_addr, stk_size);

     if (tls_addr && tls_size) ImitateTlsWrite(thr, tls_addr, tls_size);
   }
 #endif

   ThreadRegistry *tr = ctx->thread_registry;
   OnStartedArgs args = { thr, stk_addr, stk_size, tls_addr, tls_size };
   tr->StartThread(tid, os_id, workerthread, &args);

   tr->Lock();
   thr->tctx = (ThreadContext*)tr->GetThreadLocked(tid);
   tr->Unlock();

 #if !SANITIZER_GO
   if (ctx->after_multithreaded_fork) {
     thr->ignore_interceptors++;
     ThreadIgnoreBegin(thr, 0);
     ThreadIgnoreSyncBegin(thr, 0);
   }
 #endif
 }

 void ThreadFinish(ThreadState *thr) {
   ThreadCheckIgnore(thr);
   StatInc(thr, StatThreadFinish);
   if (thr->stk_addr && thr->stk_size)
     DontNeedShadowFor(thr->stk_addr, thr->stk_size);
   if (thr->tls_addr && thr->tls_size)
     DontNeedShadowFor(thr->tls_addr, thr->tls_size);
   thr->is_dead = true;
   ctx->thread_registry->FinishThread(thr->tid);
 }

 static bool FindThreadByUid(ThreadContextBase *tctx, void *arg) {
   uptr uid = (uptr)arg;
   if (tctx->user_id == uid && tctx->status != ThreadStatusInvalid) {
     tctx->user_id = 0;
     return true;
   }
   return false;
 }

 int ThreadTid(ThreadState *thr, uptr pc, uptr uid) {
   int res = ctx->thread_registry->FindThread(FindThreadByUid, (void*)uid);
   DPrintf("#%d: ThreadTid uid=%zu tid=%d\n", thr->tid, uid, res);
   return res;
 }

 void ThreadJoin(ThreadState *thr, uptr pc, int tid) {
   CHECK_GT(tid, 0);
   CHECK_LT(tid, kMaxTid);
   DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
   ctx->thread_registry->JoinThread(tid, thr);
 }

 void ThreadDetach(ThreadState *thr, uptr pc, int tid) {
   CHECK_GT(tid, 0);
   CHECK_LT(tid, kMaxTid);
   ctx->thread_registry->DetachThread(tid, thr);
 }

 void ThreadSetName(ThreadState *thr, const char *name) {
   ctx->thread_registry->SetThreadName(thr->tid, name);
 }

 void MemoryAccessRange(ThreadState *thr, uptr pc, uptr addr,
                        uptr size, bool is_write) {
   if (size == 0)
     return;

   u64 *shadow_mem = (u64*)MemToShadow(addr);
   DPrintf2("#%d: MemoryAccessRange: @%p %p size=%d is_write=%d\n",
       thr->tid, (void*)pc, (void*)addr,
       (int)size, is_write);

 #if SANITIZER_DEBUG
   if (!IsAppMem(addr)) {
     Printf("Access to non app mem %zx\n", addr);
     DCHECK(IsAppMem(addr));
   }
   if (!IsAppMem(addr + size - 1)) {
     Printf("Access to non app mem %zx\n", addr + size - 1);
     DCHECK(IsAppMem(addr + size - 1));
   }
   if (!IsShadowMem((uptr)shadow_mem)) {
     Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
     DCHECK(IsShadowMem((uptr)shadow_mem));
   }
   if (!IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1))) {
     Printf("Bad shadow addr %p (%zx)\n",
                shadow_mem + size * kShadowCnt / 8 - 1, addr + size - 1);
     DCHECK(IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1)));
   }
 #endif

   StatInc(thr, StatMopRange);

   if (*shadow_mem == kShadowRodata) {
     DCHECK(!is_write);
     // Access to .rodata section, no races here.
     // Measurements show that it can be 10-20% of all memory accesses.
     StatInc(thr, StatMopRangeRodata);
     return;
   }

   FastState fast_state = thr->fast_state;
   if (fast_state.GetIgnoreBit())
     return;

   fast_state.IncrementEpoch();
   thr->fast_state = fast_state;
   TraceAddEvent(thr, fast_state, EventTypeMop, pc);

   bool unaligned = (addr % kShadowCell) != 0;

   // Handle unaligned beginning, if any.
   for (; addr % kShadowCell && size; addr++, size--) {
     int const kAccessSizeLog = 0;
     Shadow cur(fast_state);
     cur.SetWrite(is_write);
     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
         shadow_mem, cur);
   }
   if (unaligned)
     shadow_mem += kShadowCnt;
   // Handle middle part, if any.
   for (; size >= kShadowCell; addr += kShadowCell, size -= kShadowCell) {
     int const kAccessSizeLog = 3;
     Shadow cur(fast_state);
     cur.SetWrite(is_write);
     cur.SetAddr0AndSizeLog(0, kAccessSizeLog);
     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
         shadow_mem, cur);
     shadow_mem += kShadowCnt;
   }
   // Handle ending, if any.
   for (; size; addr++, size--) {
     int const kAccessSizeLog = 0;
     Shadow cur(fast_state);
     cur.SetWrite(is_write);
     cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
     MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
         shadow_mem, cur);
   }
 }

 }  // namespace __tsan
	//===-- tsan_rtl_thread.cc ------------------------------------------------===//
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file is a part of ThreadSanitizer (TSan), a race detector.
	//
	//===----------------------------------------------------------------------===//

	#include "sanitizer_common/sanitizer_placement_new.h"
	#include "tsan_rtl.h"
	#include "tsan_mman.h"
	#include "tsan_platform.h"
	#include "tsan_report.h"
	#include "tsan_sync.h"

	namespace __tsan {

	// ThreadContext implementation.

	ThreadContext::ThreadContext(int tid)
	: ThreadContextBase(tid)
	, thr()
	, sync()
	, epoch0()
	, epoch1() {
	}

	#if !SANITIZER_GO
	ThreadContext::~ThreadContext() {
	}
	#endif

	void ThreadContext::OnDead() {
	CHECK_EQ(sync.size(), 0);
	}

	void ThreadContext::OnJoined(void *arg) {
	ThreadState caller_thr = static_cast<ThreadState >(arg);
	AcquireImpl(caller_thr, 0, &sync);
	sync.Reset(&caller_thr->proc()->clock_cache);
	}

	struct OnCreatedArgs {
	ThreadState *thr;
	uptr pc;
	};

	void ThreadContext::OnCreated(void *arg) {
	thr = 0;
	if (tid == 0)
	return;
	OnCreatedArgs args = static_cast<OnCreatedArgs >(arg);
	if (!args->thr) // GCD workers don't have a parent thread.
	return;
	args->thr->fast_state.IncrementEpoch();
	// Can't increment epoch w/o writing to the trace as well.
	TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
	ReleaseImpl(args->thr, 0, &sync);
	creation_stack_id = CurrentStackId(args->thr, args->pc);
	if (reuse_count == 0)
	StatInc(args->thr, StatThreadMaxTid);
	}

	void ThreadContext::OnReset() {
	CHECK_EQ(sync.size(), 0);
	uptr trace_p = GetThreadTrace(tid);
	ReleaseMemoryPagesToOS(trace_p, trace_p + TraceSize() * sizeof(Event));
	//!!! ReleaseMemoryToOS(GetThreadTraceHeader(tid), sizeof(Trace));
	}

	void ThreadContext::OnDetached(void *arg) {
	ThreadState thr1 = static_cast<ThreadState>(arg);
	sync.Reset(&thr1->proc()->clock_cache);
	}

	struct OnStartedArgs {
	ThreadState *thr;
	uptr stk_addr;
	uptr stk_size;
	uptr tls_addr;
	uptr tls_size;
	};

	void ThreadContext::OnStarted(void *arg) {
	OnStartedArgs args = static_cast<OnStartedArgs>(arg);
	thr = args->thr;
	// RoundUp so that one trace part does not contain events
	// from different threads.
	epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
	epoch1 = (u64)-1;
	new(thr) ThreadState(ctx, tid, unique_id, epoch0, reuse_count,
	args->stk_addr, args->stk_size, args->tls_addr, args->tls_size);
	#if !SANITIZER_GO
	thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
	thr->shadow_stack_pos = thr->shadow_stack;
	thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
	#else
	// Setup dynamic shadow stack.
	const int kInitStackSize = 8;
	thr->shadow_stack = (uptr*)internal_alloc(MBlockShadowStack,
	kInitStackSize * sizeof(uptr));
	thr->shadow_stack_pos = thr->shadow_stack;
	thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
	#endif
	if (common_flags()->detect_deadlocks)
	thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
	thr->fast_state.SetHistorySize(flags()->history_size);
	// Commit switch to the new part of the trace.
	// TraceAddEvent will reset stack0/mset0 in the new part for us.
	TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);

	thr->fast_synch_epoch = epoch0;
	AcquireImpl(thr, 0, &sync);
	StatInc(thr, StatSyncAcquire);
	sync.Reset(&thr->proc()->clock_cache);
	thr->is_inited = true;
	DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
	"tls_addr=%zx tls_size=%zx\n",
	tid, (uptr)epoch0, args->stk_addr, args->stk_size,
	args->tls_addr, args->tls_size);
	}

	void ThreadContext::OnFinished() {
	#if SANITIZER_GO
	internal_free(thr->shadow_stack);
	thr->shadow_stack = nullptr;
	thr->shadow_stack_pos = nullptr;
	thr->shadow_stack_end = nullptr;
	#endif
	if (!detached) {
	thr->fast_state.IncrementEpoch();
	// Can't increment epoch w/o writing to the trace as well.
	TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
	ReleaseImpl(thr, 0, &sync);
	}
	epoch1 = thr->fast_state.epoch();

	if (common_flags()->detect_deadlocks)
	ctx->dd->DestroyLogicalThread(thr->dd_lt);
	thr->clock.ResetCached(&thr->proc()->clock_cache);
	#if !SANITIZER_GO
	thr->last_sleep_clock.ResetCached(&thr->proc()->clock_cache);
	#endif
	thr->~ThreadState();
	#if TSAN_COLLECT_STATS
	StatAggregate(ctx->stat, thr->stat);
	#endif
	thr = 0;
	}

	#if !SANITIZER_GO
	struct ThreadLeak {
	ThreadContext *tctx;
	int count;
	};

	static void MaybeReportThreadLeak(ThreadContextBase tctx_base, void arg) {
	Vector<ThreadLeak> &leaks = (Vector<ThreadLeak>)arg;
	ThreadContext tctx = static_cast<ThreadContext>(tctx_base);
	if (tctx->detached \|\| tctx->status != ThreadStatusFinished)
	return;
	for (uptr i = 0; i < leaks.Size(); i++) {
	if (leaks[i].tctx->creation_stack_id == tctx->creation_stack_id) {
	leaks[i].count++;
	return;
	}
	}
	ThreadLeak leak = {tctx, 1};
	leaks.PushBack(leak);
	}
	#endif

	#if !SANITIZER_GO
	static void ReportIgnoresEnabled(ThreadContext tctx, IgnoreSet set) {
	if (tctx->tid == 0) {
	Printf("ThreadSanitizer: main thread finished with ignores enabled\n");
	} else {
	Printf("ThreadSanitizer: thread T%d %s finished with ignores enabled,"
	" created at:\n", tctx->tid, tctx->name);
	PrintStack(SymbolizeStackId(tctx->creation_stack_id));
	}
	Printf(" One of the following ignores was not ended"
	" (in order of probability)\n");
	for (uptr i = 0; i < set->Size(); i++) {
	Printf(" Ignore was enabled at:\n");
	PrintStack(SymbolizeStackId(set->At(i)));
	}
	Die();
	}

	static void ThreadCheckIgnore(ThreadState *thr) {
	if (ctx->after_multithreaded_fork)
	return;
	if (thr->ignore_reads_and_writes)
	ReportIgnoresEnabled(thr->tctx, &thr->mop_ignore_set);
	if (thr->ignore_sync)
	ReportIgnoresEnabled(thr->tctx, &thr->sync_ignore_set);
	}
	#else
	static void ThreadCheckIgnore(ThreadState *thr) {}
	#endif

	void ThreadFinalize(ThreadState *thr) {
	ThreadCheckIgnore(thr);
	#if !SANITIZER_GO
	if (!flags()->report_thread_leaks)
	return;
	ThreadRegistryLock l(ctx->thread_registry);
	Vector<ThreadLeak> leaks(MBlockScopedBuf);
	ctx->thread_registry->RunCallbackForEachThreadLocked(
	MaybeReportThreadLeak, &leaks);
	for (uptr i = 0; i < leaks.Size(); i++) {
	ScopedReport rep(ReportTypeThreadLeak);
	rep.AddThread(leaks[i].tctx, true);
	rep.SetCount(leaks[i].count);
	OutputReport(thr, rep);
	}
	#endif
	}

	int ThreadCount(ThreadState *thr) {
	uptr result;
	ctx->thread_registry->GetNumberOfThreads(0, 0, &result);
	return (int)result;
	}

	int ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
	StatInc(thr, StatThreadCreate);
	OnCreatedArgs args = { thr, pc };
	u32 parent_tid = thr ? thr->tid : kInvalidTid; // No parent for GCD workers.
	int tid =
	ctx->thread_registry->CreateThread(uid, detached, parent_tid, &args);
	DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", parent_tid, tid, uid);
	StatSet(thr, StatThreadMaxAlive, ctx->thread_registry->GetMaxAliveThreads());
	return tid;
	}

	void ThreadStart(ThreadState *thr, int tid, tid_t os_id, bool workerthread) {
	uptr stk_addr = 0;
	uptr stk_size = 0;
	uptr tls_addr = 0;
	uptr tls_size = 0;
	#if !SANITIZER_GO
	GetThreadStackAndTls(tid == 0, &stk_addr, &stk_size, &tls_addr, &tls_size);

	if (tid) {
	if (stk_addr && stk_size)
	MemoryRangeImitateWrite(thr, /pc=/ 1, stk_addr, stk_size);

	if (tls_addr && tls_size) ImitateTlsWrite(thr, tls_addr, tls_size);
	}
	#endif

	ThreadRegistry *tr = ctx->thread_registry;
	OnStartedArgs args = { thr, stk_addr, stk_size, tls_addr, tls_size };
	tr->StartThread(tid, os_id, workerthread, &args);

	tr->Lock();
	thr->tctx = (ThreadContext*)tr->GetThreadLocked(tid);
	tr->Unlock();

	#if !SANITIZER_GO
	if (ctx->after_multithreaded_fork) {
	thr->ignore_interceptors++;
	ThreadIgnoreBegin(thr, 0);
	ThreadIgnoreSyncBegin(thr, 0);
	}
	#endif
	}

	void ThreadFinish(ThreadState *thr) {
	ThreadCheckIgnore(thr);
	StatInc(thr, StatThreadFinish);
	if (thr->stk_addr && thr->stk_size)
	DontNeedShadowFor(thr->stk_addr, thr->stk_size);
	if (thr->tls_addr && thr->tls_size)
	DontNeedShadowFor(thr->tls_addr, thr->tls_size);
	thr->is_dead = true;
	ctx->thread_registry->FinishThread(thr->tid);
	}

	static bool FindThreadByUid(ThreadContextBase tctx, void arg) {
	uptr uid = (uptr)arg;
	if (tctx->user_id == uid && tctx->status != ThreadStatusInvalid) {
	tctx->user_id = 0;
	return true;
	}
	return false;
	}

	int ThreadTid(ThreadState *thr, uptr pc, uptr uid) {
	int res = ctx->thread_registry->FindThread(FindThreadByUid, (void*)uid);
	DPrintf("#%d: ThreadTid uid=%zu tid=%d\n", thr->tid, uid, res);
	return res;
	}

	void ThreadJoin(ThreadState *thr, uptr pc, int tid) {
	CHECK_GT(tid, 0);
	CHECK_LT(tid, kMaxTid);
	DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
	ctx->thread_registry->JoinThread(tid, thr);
	}

	void ThreadDetach(ThreadState *thr, uptr pc, int tid) {
	CHECK_GT(tid, 0);
	CHECK_LT(tid, kMaxTid);
	ctx->thread_registry->DetachThread(tid, thr);
	}

	void ThreadSetName(ThreadState thr, const char name) {
	ctx->thread_registry->SetThreadName(thr->tid, name);
	}

	void MemoryAccessRange(ThreadState *thr, uptr pc, uptr addr,
	uptr size, bool is_write) {
	if (size == 0)
	return;

	u64 shadow_mem = (u64)MemToShadow(addr);
	DPrintf2("#%d: MemoryAccessRange: @%p %p size=%d is_write=%d\n",
	thr->tid, (void)pc, (void)addr,
	(int)size, is_write);

	#if SANITIZER_DEBUG
	if (!IsAppMem(addr)) {
	Printf("Access to non app mem %zx\n", addr);
	DCHECK(IsAppMem(addr));
	}
	if (!IsAppMem(addr + size - 1)) {
	Printf("Access to non app mem %zx\n", addr + size - 1);
	DCHECK(IsAppMem(addr + size - 1));
	}
	if (!IsShadowMem((uptr)shadow_mem)) {
	Printf("Bad shadow addr %p (%zx)\n", shadow_mem, addr);
	DCHECK(IsShadowMem((uptr)shadow_mem));
	}
	if (!IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1))) {
	Printf("Bad shadow addr %p (%zx)\n",
	shadow_mem + size * kShadowCnt / 8 - 1, addr + size - 1);
	DCHECK(IsShadowMem((uptr)(shadow_mem + size * kShadowCnt / 8 - 1)));
	}
	#endif

	StatInc(thr, StatMopRange);

	if (*shadow_mem == kShadowRodata) {
	DCHECK(!is_write);
	// Access to .rodata section, no races here.
	// Measurements show that it can be 10-20% of all memory accesses.
	StatInc(thr, StatMopRangeRodata);
	return;
	}

	FastState fast_state = thr->fast_state;
	if (fast_state.GetIgnoreBit())
	return;

	fast_state.IncrementEpoch();
	thr->fast_state = fast_state;
	TraceAddEvent(thr, fast_state, EventTypeMop, pc);

	bool unaligned = (addr % kShadowCell) != 0;

	// Handle unaligned beginning, if any.
	for (; addr % kShadowCell && size; addr++, size--) {
	int const kAccessSizeLog = 0;
	Shadow cur(fast_state);
	cur.SetWrite(is_write);
	cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
	MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
	shadow_mem, cur);
	}
	if (unaligned)
	shadow_mem += kShadowCnt;
	// Handle middle part, if any.
	for (; size >= kShadowCell; addr += kShadowCell, size -= kShadowCell) {
	int const kAccessSizeLog = 3;
	Shadow cur(fast_state);
	cur.SetWrite(is_write);
	cur.SetAddr0AndSizeLog(0, kAccessSizeLog);
	MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
	shadow_mem, cur);
	shadow_mem += kShadowCnt;
	}
	// Handle ending, if any.
	for (; size; addr++, size--) {
	int const kAccessSizeLog = 0;
	Shadow cur(fast_state);
	cur.SetWrite(is_write);
	cur.SetAddr0AndSizeLog(addr & (kShadowCell - 1), kAccessSizeLog);
	MemoryAccessImpl(thr, addr, kAccessSizeLog, is_write, false,
	shadow_mem, cur);
	}
	}

	} // namespace __tsan