remove extra check

Author: SchrodingerZhu

libc/src/__support/threads/thread.cpp

@@ -154,9 +154,6 @@ ThreadAtExitCallbackMgr *get_thread_atexit_callback_mgr() {
 }
 
 void call_atexit_callbacks(ThreadAttributes *attrib) {
-  if (attrib->dtors_called)
-    return;
-  attrib->dtors_called = true;
   attrib->atexit_callback_mgr->call();
   for (size_t i = 0; i < TSS_KEY_COUNT; ++i) {
     TSSValueUnit &unit = tss_values[i];

libc/src/__support/threads/thread.h

@@ -109,14 +109,12 @@ struct alignas(STACK_ALIGNMENT) ThreadAttributes {
   ThreadReturnValue retval;
   ThreadAtExitCallbackMgr *atexit_callback_mgr;
   void *platform_data;
-  bool dtors_called;
 
   LIBC_INLINE constexpr ThreadAttributes()
       : detach_state(uint32_t(DetachState::DETACHED)), stack(nullptr),
         stacksize(0), guardsize(0), tls(0), tls_size(0), owned_stack(false),
         tid(-1), style(ThreadStyle::POSIX), retval(),
-        atexit_callback_mgr(nullptr), platform_data(nullptr),
-        dtors_called(false) {}
+        atexit_callback_mgr(nullptr), platform_data(nullptr) {}
 };
 
 using TSSDtor = void(void *);

libc/test/integration/src/__support/threads/double_exit_test.cpp

@@ -16,8 +16,18 @@ void *__dso_handle = nullptr;
 int __cxa_thread_atexit_impl(void (*func)(void *), void *arg, void *dso);
 }
 
+int call_num = 0;
+
+[[gnu::destructor]]
+void check() {
+  // This destructor should be called only once.
+  if (call_num != 1)
+    __builtin_trap();
+}
+
 TEST_MAIN() {
   __cxa_thread_atexit_impl([](void *) { LIBC_NAMESPACE::exit(0); }, nullptr,
                            __dso_handle);
-  return 0;
+  __cxa_thread_atexit_impl([](void *) { ++call_num; }, nullptr, __dso_handle);
+  LIBC_NAMESPACE::exit(1);
 }