Merge branch 'llvm18'

Upgrades the LLVM, Clang, and LLD dependencies to LLVM 18.x

Related to #16270

1 files changed, 188 insertions, 109 deletions

diff --git a/lib/libcxx/include/condition_variable b/lib/libcxx/include/condition_variable
index ac44eb3248..6aac3c13ef 100644
--- a/lib/libcxx/include/condition_variable
+++ b/lib/libcxx/include/condition_variable
@@ -100,6 +100,18 @@ public:
         wait_for(Lock& lock,
                  const chrono::duration<Rep, Period>& rel_time,
                  Predicate pred);
+
+    // [thread.condvarany.intwait], interruptible waits
+    template <class Lock, class Predicate>
+      bool wait(Lock& lock, stop_token stoken, Predicate pred);                               // since C++20
+
+    template <class Lock, class Clock, class Duration, class Predicate>
+      bool wait_until(Lock& lock, stop_token stoken,
+                      const chrono::time_point<Clock, Duration>& abs_time, Predicate pred);   // since C++20
+
+    template <class Lock, class Rep, class Period, class Predicate>
+      bool wait_for(Lock& lock, stop_token stoken,
+                    const chrono::duration<Rep, Period>& rel_time, Predicate pred);           // since C++20
 };
 
 }  // std
@@ -107,17 +119,19 @@ public:
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
+#include <__availability>
 #include <__chrono/duration.h>
 #include <__chrono/steady_clock.h>
 #include <__chrono/time_point.h>
 #include <__condition_variable/condition_variable.h>
 #include <__config>
 #include <__memory/shared_ptr.h>
-#include <__memory/unique_ptr.h>
 #include <__mutex/lock_guard.h>
 #include <__mutex/mutex.h>
 #include <__mutex/tag_types.h>
 #include <__mutex/unique_lock.h>
+#include <__stop_token/stop_callback.h>
+#include <__stop_token/stop_token.h>
 #include <__utility/move.h>
 #include <version>
 
@@ -125,156 +139,220 @@ public:
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 #ifndef _LIBCPP_HAS_NO_THREADS
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-class _LIBCPP_EXPORTED_FROM_ABI condition_variable_any
-{
-    condition_variable __cv_;
-    shared_ptr<mutex>  __mut_;
+class _LIBCPP_EXPORTED_FROM_ABI condition_variable_any {
+  condition_variable __cv_;
+  shared_ptr<mutex> __mut_;
+
 public:
-    _LIBCPP_INLINE_VISIBILITY
-    condition_variable_any();
+  _LIBCPP_HIDE_FROM_ABI condition_variable_any();
 
-    _LIBCPP_INLINE_VISIBILITY
-    void notify_one() _NOEXCEPT;
-    _LIBCPP_INLINE_VISIBILITY
-    void notify_all() _NOEXCEPT;
+  _LIBCPP_HIDE_FROM_ABI void notify_one() _NOEXCEPT;
+  _LIBCPP_HIDE_FROM_ABI void notify_all() _NOEXCEPT;
 
-    template <class _Lock>
-        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
-        void wait(_Lock& __lock);
-    template <class _Lock, class _Predicate>
-        _LIBCPP_INLINE_VISIBILITY
-        void wait(_Lock& __lock, _Predicate __pred);
+  template <class _Lock>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS void wait(_Lock& __lock);
+  template <class _Lock, class _Predicate>
+  _LIBCPP_HIDE_FROM_ABI void wait(_Lock& __lock, _Predicate __pred);
 
-    template <class _Lock, class _Clock, class _Duration>
-        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
-        cv_status
-        wait_until(_Lock& __lock,
-                   const chrono::time_point<_Clock, _Duration>& __t);
+  template <class _Lock, class _Clock, class _Duration>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS cv_status
+  wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t);
 
-    template <class _Lock, class _Clock, class _Duration, class _Predicate>
-        bool
-        _LIBCPP_INLINE_VISIBILITY
-        wait_until(_Lock& __lock,
-                   const chrono::time_point<_Clock, _Duration>& __t,
-                   _Predicate __pred);
+  template <class _Lock, class _Clock, class _Duration, class _Predicate>
+  bool _LIBCPP_HIDE_FROM_ABI
+  wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred);
 
-    template <class _Lock, class _Rep, class _Period>
-        cv_status
-        _LIBCPP_INLINE_VISIBILITY
-        wait_for(_Lock& __lock,
-                 const chrono::duration<_Rep, _Period>& __d);
+  template <class _Lock, class _Rep, class _Period>
+  cv_status _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d);
 
-    template <class _Lock, class _Rep, class _Period, class _Predicate>
-        bool
-        _LIBCPP_INLINE_VISIBILITY
-        wait_for(_Lock& __lock,
-                 const chrono::duration<_Rep, _Period>& __d,
-                 _Predicate __pred);
+  template <class _Lock, class _Rep, class _Period, class _Predicate>
+  bool _LIBCPP_HIDE_FROM_ABI wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred);
+
+#  if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN)
+
+  template <class _Lock, class _Predicate>
+  _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait(_Lock& __lock, stop_token __stoken, _Predicate __pred);
+
+  template <class _Lock, class _Clock, class _Duration, class _Predicate>
+  _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool wait_until(
+      _Lock& __lock, stop_token __stoken, const chrono::time_point<_Clock, _Duration>& __abs_time, _Predicate __pred);
+
+  template <class _Lock, class _Rep, class _Period, class _Predicate>
+  _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool
+  wait_for(_Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred);
+
+#  endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN)
 };
 
-inline
-condition_variable_any::condition_variable_any()
-    : __mut_(make_shared<mutex>()) {}
+inline condition_variable_any::condition_variable_any() : __mut_(make_shared<mutex>()) {}
 
-inline
-void
-condition_variable_any::notify_one() _NOEXCEPT
-{
-    {lock_guard<mutex> __lx(*__mut_);}
-    __cv_.notify_one();
+inline void condition_variable_any::notify_one() _NOEXCEPT {
+  { lock_guard<mutex> __lx(*__mut_); }
+  __cv_.notify_one();
 }
 
-inline
-void
-condition_variable_any::notify_all() _NOEXCEPT
-{
-    {lock_guard<mutex> __lx(*__mut_);}
-    __cv_.notify_all();
+inline void condition_variable_any::notify_all() _NOEXCEPT {
+  { lock_guard<mutex> __lx(*__mut_); }
+  __cv_.notify_all();
 }
 
-struct __lock_external
-{
-    template <class _Lock>
-    _LIBCPP_HIDE_FROM_ABI void operator()(_Lock* __m) {__m->lock();}
+template <class _Lock>
+struct __unlock_guard {
+  _Lock& __lock_;
+
+  _LIBCPP_HIDE_FROM_ABI __unlock_guard(_Lock& __lock) : __lock_(__lock) { __lock_.unlock(); }
+
+  _LIBCPP_HIDE_FROM_ABI ~__unlock_guard() _NOEXCEPT // turns exception to std::terminate
+  {
+    __lock_.lock();
+  }
+
+  __unlock_guard(const __unlock_guard&)            = delete;
+  __unlock_guard& operator=(const __unlock_guard&) = delete;
 };
 
 template <class _Lock>
-void
-condition_variable_any::wait(_Lock& __lock)
-{
-    shared_ptr<mutex> __mut = __mut_;
-    unique_lock<mutex> __lk(*__mut);
-    __lock.unlock();
-    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
-    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t());
-    __cv_.wait(__lk);
-}  // __mut_.unlock(), __lock.lock()
+void condition_variable_any::wait(_Lock& __lock) {
+  shared_ptr<mutex> __mut = __mut_;
+  unique_lock<mutex> __lk(*__mut);
+  __unlock_guard<_Lock> __unlock(__lock);
+  lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t());
+  __cv_.wait(__lk);
+} // __mut_.unlock(), __lock.lock()
 
 template <class _Lock, class _Predicate>
-inline
-void
-condition_variable_any::wait(_Lock& __lock, _Predicate __pred)
-{
-    while (!__pred())
-        wait(__lock);
+inline void condition_variable_any::wait(_Lock& __lock, _Predicate __pred) {
+  while (!__pred())
+    wait(__lock);
 }
 
 template <class _Lock, class _Clock, class _Duration>
-cv_status
-condition_variable_any::wait_until(_Lock& __lock,
-                                   const chrono::time_point<_Clock, _Duration>& __t)
-{
-    shared_ptr<mutex> __mut = __mut_;
-    unique_lock<mutex> __lk(*__mut);
-    __lock.unlock();
-    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
-    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t());
-    return __cv_.wait_until(__lk, __t);
-}  // __mut_.unlock(), __lock.lock()
+cv_status condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t) {
+  shared_ptr<mutex> __mut = __mut_;
+  unique_lock<mutex> __lk(*__mut);
+  __unlock_guard<_Lock> __unlock(__lock);
+  lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock_t());
+  return __cv_.wait_until(__lk, __t);
+} // __mut_.unlock(), __lock.lock()
 
 template <class _Lock, class _Clock, class _Duration, class _Predicate>
-inline
-bool
-condition_variable_any::wait_until(_Lock& __lock,
-                                   const chrono::time_point<_Clock, _Duration>& __t,
-                                   _Predicate __pred)
-{
-    while (!__pred())
-        if (wait_until(__lock, __t) == cv_status::timeout)
-            return __pred();
-    return true;
+inline bool
+condition_variable_any::wait_until(_Lock& __lock, const chrono::time_point<_Clock, _Duration>& __t, _Predicate __pred) {
+  while (!__pred())
+    if (wait_until(__lock, __t) == cv_status::timeout)
+      return __pred();
+  return true;
 }
 
 template <class _Lock, class _Rep, class _Period>
-inline
-cv_status
-condition_variable_any::wait_for(_Lock& __lock,
-                                 const chrono::duration<_Rep, _Period>& __d)
-{
-    return wait_until(__lock, chrono::steady_clock::now() + __d);
+inline cv_status condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d) {
+  return wait_until(__lock, chrono::steady_clock::now() + __d);
 }
 
 template <class _Lock, class _Rep, class _Period, class _Predicate>
-inline
-bool
-condition_variable_any::wait_for(_Lock& __lock,
-                                 const chrono::duration<_Rep, _Period>& __d,
-                                 _Predicate __pred)
-{
-    return wait_until(__lock, chrono::steady_clock::now() + __d,
-                      _VSTD::move(__pred));
+inline bool
+condition_variable_any::wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __d, _Predicate __pred) {
+  return wait_until(__lock, chrono::steady_clock::now() + __d, std::move(__pred));
+}
+
+#  if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN)
+
+template <class _Lock, class _Predicate>
+bool condition_variable_any::wait(_Lock& __user_lock, stop_token __stoken, _Predicate __pred) {
+  if (__stoken.stop_requested())
+    return __pred();
+
+  // Per https://eel.is/c++draft/thread.condition.condvarany#general-note-2,
+  // we do need to take a copy of the shared pointer __mut_
+  // This ensures that a thread can call the destructor immediately after calling
+  // notify_all, without waiting all the wait calls.
+  // A thread can also safely call the destructor immediately after calling
+  // request_stop, as the call to request_stop would evaluate the callback,
+  // which accesses the internal condition variable, immediately on the same thread.
+  // In this situation, it is OK even without copying a shared ownership the internal
+  // condition variable. However, this needs the evaluation of stop_callback to
+  // happen-before the destruction.
+  // The spec only says "Only the notification to unblock the wait needs to happen
+  // before destruction". To make this work, we need to copy the shared ownership of
+  // the internal condition variable inside this function, which is not possible
+  // with the current ABI.
+  shared_ptr<mutex> __mut = __mut_;
+
+  stop_callback __cb(__stoken, [this] { notify_all(); });
+
+  while (true) {
+    if (__pred())
+      return true;
+
+    // We need to take the internal lock before checking stop_requested,
+    // so that the notification cannot come in between the stop_requested
+    // check and entering the wait.
+    // Note that the stop_callback takes the same internal lock before notifying
+    unique_lock<mutex> __internal_lock(*__mut);
+    if (__stoken.stop_requested())
+      break;
+
+    __unlock_guard<_Lock> __unlock(__user_lock);
+    unique_lock<mutex> __internal_lock2(
+        std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock
+    __cv_.wait(__internal_lock2);
+  } // __internal_lock2.unlock(), __user_lock.lock()
+  return __pred();
+}
+
+template <class _Lock, class _Clock, class _Duration, class _Predicate>
+bool condition_variable_any::wait_until(
+    _Lock& __user_lock,
+    stop_token __stoken,
+    const chrono::time_point<_Clock, _Duration>& __abs_time,
+    _Predicate __pred) {
+  if (__stoken.stop_requested())
+    return __pred();
+
+  shared_ptr<mutex> __mut = __mut_;
+  stop_callback __cb(__stoken, [this] { notify_all(); });
+
+  while (true) {
+    if (__pred())
+      return true;
+
+    unique_lock<mutex> __internal_lock(*__mut);
+    if (__stoken.stop_requested())
+      break;
+
+    __unlock_guard<_Lock> __unlock(__user_lock);
+    unique_lock<mutex> __internal_lock2(
+        std::move(__internal_lock)); // switch unlock order between __internal_lock and __user_lock
+
+    if (__cv_.wait_until(__internal_lock2, __abs_time) == cv_status::timeout)
+      break;
+  } // __internal_lock2.unlock(), __user_lock.lock()
+  return __pred();
 }
 
+template <class _Lock, class _Rep, class _Period, class _Predicate>
+bool condition_variable_any::wait_for(
+    _Lock& __lock, stop_token __stoken, const chrono::duration<_Rep, _Period>& __rel_time, _Predicate __pred) {
+  return wait_until(__lock, std::move(__stoken), chrono::steady_clock::now() + __rel_time, std::move(__pred));
+}
+
+#  endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN)
+
 _LIBCPP_EXPORTED_FROM_ABI void notify_all_at_thread_exit(condition_variable&, unique_lock<mutex>);
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // !_LIBCPP_HAS_NO_THREADS
 
+_LIBCPP_POP_MACROS
+
 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
 #  include <atomic>
 #  include <concepts>
@@ -282,6 +360,7 @@ _LIBCPP_END_NAMESPACE_STD
 #  include <cstdlib>
 #  include <cstring>
 #  include <initializer_list>
+#  include <iosfwd>
 #  include <new>
 #  include <stdexcept>
 #  include <system_error>