[vm] Use C++11 thread_local for TLS destructors.

Removes linker hack on Windows.

TEST=ci
Change-Id: Ib031f8f05e422084fa6652fee425f8e46884840e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/490341
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/vm/os_thread.cc

@@ -16,12 +16,10 @@
 
 namespace dart {
 
-// The single thread local key which stores all the thread local data
-// for a thread.
-ThreadLocalKey OSThread::thread_key_ = kUnsetThreadLocalKey;
 OSThread* OSThread::thread_list_head_ = nullptr;
 Mutex* OSThread::thread_list_lock_ = nullptr;
 bool OSThread::creation_enabled_ = false;
+thread_local OSThreadPtr OSThread::current_os_thread_ = {};
 
 #if defined(SUPPORT_TIMELINE)
 inline void UpdateTimelineTrackMetadata(const OSThread& thread) {
@@ -87,6 +85,11 @@ OSThread* OSThread::CreateOSThread() {
   return os_thread;
 }
 
+OSThreadPtr::~OSThreadPtr() {
+  delete thread_;
+  thread_ = nullptr;
+}
+
 OSThread::~OSThread() {
   if (!is_os_thread()) {
     // If the embedder enters an isolate on this thread and does not exit the
@@ -169,11 +172,6 @@ bool OSThread::ThreadInterruptsEnabled() {
 }
 #endif  // defined(DART_INCLUDE_PROFILER)
 
-static void DeleteThread(void* thread) {
-  MSAN_UNPOISON(&thread, sizeof(thread));
-  delete reinterpret_cast<OSThread*>(thread);
-}
-
 void OSThread::Init() {
   // Allocate the global OSThread lock.
   if (thread_list_lock_ == nullptr) {
@@ -181,12 +179,6 @@ void OSThread::Init() {
   }
   ASSERT(thread_list_lock_ != nullptr);
 
-  // Create the thread local key.
-  if (thread_key_ == kUnsetThreadLocalKey) {
-    thread_key_ = CreateThreadLocal(DeleteThread);
-  }
-  ASSERT(thread_key_ != kUnsetThreadLocalKey);
-
   // Enable creation of OSThread structures in the VM.
   EnableOSThreadCreation();
 
@@ -198,15 +190,10 @@ void OSThread::Init() {
 }
 
 void OSThread::Cleanup() {
-// We cannot delete the thread local key and thread list lock,  yet.
+// We cannot delete the thread list lock, yet.
 // See the note on thread_list_lock_ in os_thread.h.
 #if 0
   if (thread_list_lock_ != nullptr) {
-    // Delete the thread local key.
-    ASSERT(thread_key_ != kUnsetThreadLocalKey);
-    DeleteThreadLocal(thread_key_);
-    thread_key_ = kUnsetThreadLocalKey;
-
     // Delete the global OSThread lock.
     ASSERT(thread_list_lock_ != nullptr);
     delete thread_list_lock_;
@@ -331,7 +318,7 @@ void OSThread::RemoveThreadFromList(OSThread* thread) {
 DART_NOINLINE
 void OSThread::SetCurrentTLS(BaseThread* value) {
   // Provides thread-local destructors.
-  SetThreadLocal(thread_key_, reinterpret_cast<uword>(value));
+  current_os_thread_.set(static_cast<OSThread*>(value));
 
   // Allows the C compiler more freedom to optimize.
   if ((value != nullptr) && !value->is_os_thread()) {

runtime/vm/os_thread.h

@@ -58,6 +58,21 @@ class BaseThread {
 
 using ThreadId = platform::ThreadId;
 
+class OSThread;
+
+// Wrapper to get TLS destructor.
+class OSThreadPtr {
+ public:
+  constexpr OSThreadPtr() {}
+  ~OSThreadPtr();
+
+  OSThread* get() const { return thread_; }
+  void set(OSThread* value) { thread_ = value; }
+
+ private:
+  OSThread* thread_ = nullptr;
+};
+
 // Low-level operations on OS platform threads.
 class OSThread : public BaseThread {
  public:
@@ -182,9 +197,7 @@ class OSThread : public BaseThread {
     uword stack_size = OSThread::GetMaxStackSize() - headroom;
     return stack_size;
   }
-  static BaseThread* GetCurrentTLS() {
-    return reinterpret_cast<BaseThread*>(OSThread::GetThreadLocal(thread_key_));
-  }
+  static BaseThread* GetCurrentTLS() { return current_os_thread_.get(); }
   static void SetCurrentTLS(BaseThread* value);
 
   typedef void (*ThreadStartFunction)(uword parameter);
@@ -202,13 +215,6 @@ class OSThread : public BaseThread {
                     ThreadStartFunction function,
                     uword parameter);
 
-  static ThreadLocalKey CreateThreadLocal(
-      ThreadDestructor destructor = nullptr);
-  static void DeleteThreadLocal(ThreadLocalKey key);
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    return ThreadInlineImpl::GetThreadLocal(key);
-  }
-  static void SetThreadLocal(ThreadLocalKey key, uword value);
   static intptr_t GetMaxStackSize();
   static void Join(ThreadJoinId id);
   static void Detach(ThreadJoinId id);
@@ -273,8 +279,6 @@ class OSThread : public BaseThread {
     return (headroom > kStackSizeBufferMax) ? kStackSizeBufferMax : headroom;
   }
 
-  static ThreadLocalKey thread_key_;
-
   const ThreadId id_;
 #if defined(DEBUG)
   // In DEBUG mode we use this field to ensure that GetCurrentThreadJoinId is
@@ -322,6 +326,10 @@ class OSThread : public BaseThread {
   // initialization checks at each use.
   static inline thread_local ThreadState* current_vm_thread_ = nullptr;
 
+  // Inline initialization results in duplicate definition link errors on Mac.
+  // But this TLS is rarely accessed, so the guard doesn't matter much.
+  static thread_local OSThreadPtr current_os_thread_;
+
   friend class Thread;  // to access set_thread(Thread*).
   friend class OSThreadIterator;
   friend class ThreadInterrupterFuchsia;

runtime/vm/os_thread_absl.cc

@@ -148,26 +148,6 @@ int OSThread::TryStart(const char* name,
 const ThreadJoinId OSThread::kInvalidThreadJoinId =
     static_cast<ThreadJoinId>(0);
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  pthread_key_t key = kUnsetThreadLocalKey;
-  int result = pthread_key_create(&key, destructor);
-  VALIDATE_PTHREAD_RESULT(result);
-  ASSERT(key != kUnsetThreadLocalKey);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_key_delete(key);
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_setspecific(key, reinterpret_cast<void*>(value));
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;
@@ -217,7 +197,7 @@ void OSThread::Join(ThreadJoinId id) {
 }
 
 void OSThread::Detach(ThreadJoinId id) {
-  int result = pthread_detach(id);
+  int result = pthread_detach(id);  // NOLINT
   VALIDATE_PTHREAD_RESULT(result);
 }
 

runtime/vm/os_thread_absl.h

@@ -16,28 +16,8 @@
 
 namespace dart {
 
-typedef pthread_key_t ThreadLocalKey;
 typedef pthread_t ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey =
-    static_cast<pthread_key_t>(-1);
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(pthread_getspecific(key));
-  }
-
-  friend class OSThread;
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_ABSL_H_

runtime/vm/os_thread_android.cc

@@ -126,26 +126,6 @@ int OSThread::TryStart(const char* name,
 const ThreadJoinId OSThread::kInvalidThreadJoinId =
     static_cast<ThreadJoinId>(0);
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  pthread_key_t key = kUnsetThreadLocalKey;
-  int result = pthread_key_create(&key, destructor);
-  VALIDATE_PTHREAD_RESULT(result);
-  ASSERT(key != kUnsetThreadLocalKey);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_key_delete(key);
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_setspecific(key, reinterpret_cast<void*>(value));
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;
@@ -183,7 +163,7 @@ void OSThread::Join(ThreadJoinId id) {
 }
 
 void OSThread::Detach(ThreadJoinId id) {
-  int result = pthread_detach(id);
+  int result = pthread_detach(id);  // NOLINT
   VALIDATE_PTHREAD_RESULT(result);
 }
 

runtime/vm/os_thread_android.h

@@ -16,28 +16,8 @@
 
 namespace dart {
 
-typedef pthread_key_t ThreadLocalKey;
 typedef pthread_t ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey =
-    static_cast<pthread_key_t>(-1);
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(pthread_getspecific(key));
-  }
-
-  friend class OSThread;
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_ANDROID_H_

runtime/vm/os_thread_fuchsia.cc

@@ -96,26 +96,6 @@ int OSThread::TryStart(const char* name,
 const ThreadJoinId OSThread::kInvalidThreadJoinId =
     static_cast<ThreadJoinId>(0);
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  pthread_key_t key = kUnsetThreadLocalKey;
-  int result = pthread_key_create(&key, destructor);
-  VALIDATE_PTHREAD_RESULT(result);
-  ASSERT(key != kUnsetThreadLocalKey);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_key_delete(key);
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_setspecific(key, reinterpret_cast<void*>(value));
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;

runtime/vm/os_thread_fuchsia.h

@@ -17,28 +17,8 @@
 
 namespace dart {
 
-typedef pthread_key_t ThreadLocalKey;
 typedef pthread_t ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey =
-    static_cast<pthread_key_t>(-1);
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(pthread_getspecific(key));
-  }
-
-  friend class OSThread;
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_FUCHSIA_H_

runtime/vm/os_thread_linux.cc

@@ -125,26 +125,6 @@ int OSThread::TryStart(const char* name,
 const ThreadJoinId OSThread::kInvalidThreadJoinId =
     static_cast<ThreadJoinId>(0);
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  pthread_key_t key = kUnsetThreadLocalKey;
-  int result = pthread_key_create(&key, destructor);
-  VALIDATE_PTHREAD_RESULT(result);
-  ASSERT(key != kUnsetThreadLocalKey);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_key_delete(key);
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_setspecific(key, reinterpret_cast<void*>(value));
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;
@@ -182,7 +162,7 @@ void OSThread::Join(ThreadJoinId id) {
 }
 
 void OSThread::Detach(ThreadJoinId id) {
-  int result = pthread_detach(id);
+  int result = pthread_detach(id);  // NOLINT
   VALIDATE_PTHREAD_RESULT(result);
 }
 

runtime/vm/os_thread_linux.h

@@ -16,28 +16,8 @@
 
 namespace dart {
 
-typedef pthread_key_t ThreadLocalKey;
 typedef pthread_t ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey =
-    static_cast<pthread_key_t>(-1);
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(pthread_getspecific(key));
-  }
-
-  friend class OSThread;
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_LINUX_H_

runtime/vm/os_thread_macos.cc

@@ -122,26 +122,6 @@ int OSThread::TryStart(const char* name,
 const ThreadJoinId OSThread::kInvalidThreadJoinId =
     static_cast<ThreadJoinId>(nullptr);
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  pthread_key_t key = kUnsetThreadLocalKey;
-  int result = pthread_key_create(&key, destructor);
-  VALIDATE_PTHREAD_RESULT(result);
-  ASSERT(key != kUnsetThreadLocalKey);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_key_delete(key);
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  int result = pthread_setspecific(key, reinterpret_cast<void*>(value));
-  VALIDATE_PTHREAD_RESULT(result);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;
@@ -179,7 +159,7 @@ void OSThread::Join(ThreadJoinId id) {
 }
 
 void OSThread::Detach(ThreadJoinId id) {
-  int result = pthread_detach(id);
+  int result = pthread_detach(id);  // NOLINT
   VALIDATE_PTHREAD_RESULT(result);
 }
 

runtime/vm/os_thread_macos.h

@@ -16,29 +16,8 @@
 
 namespace dart {
 
-typedef pthread_key_t ThreadLocalKey;
 typedef pthread_t ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey =
-    static_cast<pthread_key_t>(-1);
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    static ThreadLocalKey kUnsetThreadLocalKey = static_cast<pthread_key_t>(-1);
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(pthread_getspecific(key));
-  }
-
-  friend class OSThread;
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_MACOS_H_

runtime/vm/os_thread_win.cc

@@ -98,30 +98,6 @@ int OSThread::TryStart(const char* name,
 
 const ThreadJoinId OSThread::kInvalidThreadJoinId = nullptr;
 
-ThreadLocalKey OSThread::CreateThreadLocal(ThreadDestructor destructor) {
-  ThreadLocalKey key = TlsAlloc();
-  if (key == kUnsetThreadLocalKey) {
-    int error = GetLastError();
-    char buffer[1024];
-    FATAL("TlsAlloc failed %d (%s)\n", error,
-          Utils::StrError(error, buffer, sizeof(buffer)));
-  }
-  ThreadLocalData::AddThreadLocal(key, destructor);
-  return key;
-}
-
-void OSThread::DeleteThreadLocal(ThreadLocalKey key) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  BOOL result = TlsFree(key);
-  if (!result) {
-    int error = GetLastError();
-    char buffer[1024];
-    FATAL("TlsFree failed %d (%s)\n", error,
-          Utils::StrError(error, buffer, sizeof(buffer)));
-  }
-  ThreadLocalData::RemoveThreadLocal(key);
-}
-
 intptr_t OSThread::GetMaxStackSize() {
   const int kStackSize = (128 * kWordSize * KB);
   return kStackSize;
@@ -199,172 +175,6 @@ void OSThread::SetCurrentSafestackPointer(uword ssp) {
 }
 #endif
 
-void OSThread::SetThreadLocal(ThreadLocalKey key, uword value) {
-  ASSERT(key != kUnsetThreadLocalKey);
-  BOOL result = TlsSetValue(key, reinterpret_cast<void*>(value));
-  if (!result) {
-    int error = GetLastError();
-    char buffer[1024];
-    FATAL("TlsSetValue failed %d (%s)\n", error,
-          Utils::StrError(error, buffer, sizeof(buffer)));
-  }
-}
-
-void ThreadLocalData::AddThreadLocal(ThreadLocalKey key,
-                                     ThreadDestructor destructor) {
-  ASSERT(thread_locals_ != nullptr);
-  if (destructor == nullptr) {
-    // We only care about thread locals with destructors.
-    return;
-  }
-  MutexLocker ml(mutex_);
-#if defined(DEBUG)
-  // Verify that we aren't added twice.
-  for (intptr_t i = 0; i < thread_locals_->length(); i++) {
-    const ThreadLocalEntry& entry = thread_locals_->At(i);
-    ASSERT(entry.key() != key);
-  }
-#endif
-  // Add to list.
-  thread_locals_->Add(ThreadLocalEntry(key, destructor));
-}
-
-void ThreadLocalData::RemoveThreadLocal(ThreadLocalKey key) {
-  ASSERT(thread_locals_ != nullptr);
-  MutexLocker ml(mutex_);
-  intptr_t i = 0;
-  for (; i < thread_locals_->length(); i++) {
-    const ThreadLocalEntry& entry = thread_locals_->At(i);
-    if (entry.key() == key) {
-      break;
-    }
-  }
-  if (i == thread_locals_->length()) {
-    // Not found.
-    return;
-  }
-  thread_locals_->RemoveAt(i);
-}
-
-// This function is executed on the thread that is exiting. It is invoked
-// by |OnDartThreadExit| (see below for notes on TLS destructors on Windows).
-void ThreadLocalData::RunDestructors() {
-  // If an OS thread is created but ThreadLocalData::Init has not yet been
-  // called, this method still runs. If this happens, there's nothing to clean
-  // up here. See issue 33826.
-  if (thread_locals_ == nullptr) {
-    return;
-  }
-  ASSERT(mutex_ != nullptr);
-  MutexLocker ml(mutex_);
-  for (intptr_t i = 0; i < thread_locals_->length(); i++) {
-    const ThreadLocalEntry& entry = thread_locals_->At(i);
-    // We access the exiting thread's TLS variable here.
-    void* p = reinterpret_cast<void*>(OSThread::GetThreadLocal(entry.key()));
-    // We invoke the constructor here.
-    entry.destructor()(p);
-  }
-}
-
-Mutex* ThreadLocalData::mutex_ = nullptr;
-MallocGrowableArray<ThreadLocalEntry>* ThreadLocalData::thread_locals_ =
-    nullptr;
-
-void ThreadLocalData::Init() {
-  mutex_ = new Mutex();
-  thread_locals_ = new MallocGrowableArray<ThreadLocalEntry>();
-}
-
-void ThreadLocalData::Cleanup() {
-  if (mutex_ != nullptr) {
-    delete mutex_;
-    mutex_ = nullptr;
-  }
-  if (thread_locals_ != nullptr) {
-    delete thread_locals_;
-    thread_locals_ = nullptr;
-  }
-}
-
 }  // namespace dart
 
-// The following was adapted from Chromium:
-// src/base/threading/thread_local_storage_win.cc
-
-// Thread Termination Callbacks.
-// Windows doesn't support a per-thread destructor with its
-// TLS primitives.  So, we build it manually by inserting a
-// function to be called on each thread's exit.
-// This magic is from http://www.codeproject.com/threads/tls.asp
-// and it works for VC++ 7.0 and later.
-
-// Force a reference to _tls_used to make the linker create the TLS directory
-// if it's not already there.  (e.g. if __declspec(thread) is not used).
-// Force a reference to p_thread_callback_dart to prevent whole program
-// optimization from discarding the variable.
-#ifdef _WIN64
-
-#pragma comment(linker, "/INCLUDE:_tls_used")
-#pragma comment(linker, "/INCLUDE:p_thread_callback_dart")
-
-#else  // _WIN64
-
-#pragma comment(linker, "/INCLUDE:__tls_used")
-#pragma comment(linker, "/INCLUDE:_p_thread_callback_dart")
-
-#endif  // _WIN64
-
-// Static callback function to call with each thread termination.
-void NTAPI OnDartThreadExit(PVOID module, DWORD reason, PVOID reserved) {
-  if (!dart::private_flag_windows_run_tls_destructors) {
-    return;
-  }
-  // On XP SP0 & SP1, the DLL_PROCESS_ATTACH is never seen. It is sent on SP2+
-  // and on W2K and W2K3. So don't assume it is sent.
-  if (DLL_THREAD_DETACH == reason || DLL_PROCESS_DETACH == reason) {
-    dart::ThreadLocalData::RunDestructors();
-  }
-}
-
-// .CRT$XLA to .CRT$XLZ is an array of PIMAGE_TLS_CALLBACK pointers that are
-// called automatically by the OS loader code (not the CRT) when the module is
-// loaded and on thread creation. They are NOT called if the module has been
-// loaded by a LoadLibrary() call. It must have implicitly been loaded at
-// process startup.
-// By implicitly loaded, I mean that it is directly referenced by the main EXE
-// or by one of its dependent DLLs. Delay-loaded DLL doesn't count as being
-// implicitly loaded.
-//
-// See VC\crt\src\tlssup.c for reference.
-
-// extern "C" suppresses C++ name mangling so we know the symbol name for the
-// linker /INCLUDE:symbol pragma above.
-extern "C" {
-// The linker must not discard p_thread_callback_dart.  (We force a reference
-// to this variable with a linker /INCLUDE:symbol pragma to ensure that.) If
-// this variable is discarded, the OnDartThreadExit function will never be
-// called.
-#ifdef _WIN64
-
-// .CRT section is merged with .rdata on x64 so it must be constant data.
-#pragma const_seg(".CRT$XLB")
-// When defining a const variable, it must have external linkage to be sure the
-// linker doesn't discard it.
-extern const PIMAGE_TLS_CALLBACK p_thread_callback_dart;
-const PIMAGE_TLS_CALLBACK p_thread_callback_dart = OnDartThreadExit;
-
-// Reset the default section.
-#pragma const_seg()
-
-#else  // _WIN64
-
-#pragma data_seg(".CRT$XLB")
-PIMAGE_TLS_CALLBACK p_thread_callback_dart = OnDartThreadExit;
-
-// Reset the default section.
-#pragma data_seg()
-
-#endif  // _WIN64
-}  // extern "C"
-
 #endif  // defined(DART_HOST_OS_WINDOWS) && !defined(DART_USE_ABSL)

runtime/vm/os_thread_win.h

@@ -16,67 +16,8 @@
 
 namespace dart {
 
-typedef DWORD ThreadLocalKey;
 typedef HANDLE ThreadJoinId;
 
-static const ThreadLocalKey kUnsetThreadLocalKey = TLS_OUT_OF_INDEXES;
-
-class ThreadInlineImpl {
- private:
-  ThreadInlineImpl() {}
-  ~ThreadInlineImpl() {}
-
-  static uword GetThreadLocal(ThreadLocalKey key) {
-    ASSERT(key != kUnsetThreadLocalKey);
-    return reinterpret_cast<uword>(TlsGetValue(key));
-  }
-
-  friend class OSThread;
-  friend unsigned int __stdcall ThreadEntry(void* data_ptr);
-
-  DISALLOW_ALLOCATION();
-  DISALLOW_COPY_AND_ASSIGN(ThreadInlineImpl);
-};
-
-typedef void (*ThreadDestructor)(void* parameter);
-
-class ThreadLocalEntry {
- public:
-  ThreadLocalEntry(ThreadLocalKey key, ThreadDestructor destructor)
-      : key_(key), destructor_(destructor) {}
-
-  ThreadLocalKey key() const { return key_; }
-
-  ThreadDestructor destructor() const { return destructor_; }
-
- private:
-  ThreadLocalKey key_;
-  ThreadDestructor destructor_;
-
-  DISALLOW_ALLOCATION();
-};
-
-template <typename T>
-class MallocGrowableArray;
-
-class ThreadLocalData : public AllStatic {
- public:
-  static void RunDestructors();
-
- private:
-  static void AddThreadLocal(ThreadLocalKey key, ThreadDestructor destructor);
-  static void RemoveThreadLocal(ThreadLocalKey key);
-
-  static Mutex* mutex_;
-  static MallocGrowableArray<ThreadLocalEntry>* thread_locals_;
-
-  static void Init();
-  static void Cleanup();
-
-  friend class OS;
-  friend class OSThread;
-};
-
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OS_THREAD_WIN_H_

runtime/vm/os_win.cc

@@ -368,7 +368,6 @@ void OS::Init() {
   init_once_called = true;
   // Do not pop up a message box when abort is called.
   _set_abort_behavior(0, _WRITE_ABORT_MSG);
-  ThreadLocalData::Init();
   LARGE_INTEGER ticks_per_sec;
   if (!QueryPerformanceFrequency(&ticks_per_sec)) {
     qpc_ticks_per_second = 0;
@@ -377,10 +376,7 @@ void OS::Init() {
   }
 }
 
-void OS::Cleanup() {
-  // TODO(zra): Enable once VM can shutdown cleanly.
-  // ThreadLocalData::Cleanup();
-}
+void OS::Cleanup() {}
 
 void OS::PrepareToAbort() {
   // TODO(zra): Remove once VM shuts down cleanly.