[clang-tools-extra] [clang-tidy] Add check to diagnose coroutine-hostile RAII objects (PR #68738)

[Piotr Zegar via cfe-commits]

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+.. title:: clang-tidy - misc-coroutine-hostile-raii
+
+misc-coroutine-hostile-raii
+====================
+
+This check detects hostile-RAII objects which should not persist across a 
+suspension point in a coroutine.
+
+Some objects require that they be destroyed on the same thread that created them. 
+Traditionally this requirement was often phrased as "must be a local variable",
+under the assumption that local variables always work this way. However this is
+incorrect with C++20 coroutines, since an intervening `co_await` may cause the
+coroutine to suspend and later be resumed on another thread.
+
+The lifetime of an object that requires being destroyed on the same thread must 
+not encompass a `co_await` or `co_yield` point. If you create/destroy an object,
+you must do so without allowing the coroutine to suspend in the meantime.
+
+The check considers the following type as hostile:
+
+ - Scoped-lockable types: A scoped-lockable object persisting across a suspension
+ point is problematic as the lock held by this object could be unlocked by a 
+ different thread. This would be undefined behaviour.
+
+ - Types belonging to a configurable denylist.
+
+.. code-block:: c++
+
+  // Call some async API while holding a lock.
+  {
+    const my::MutexLock l(&mu_);
+
+    // Oops! The async Bar function may finish on a different
+    // thread from the one that created the MutexLock object and therefore called
+    // Mutex::Lock -- now Mutex::Unlock will be called on the wrong thread.
+    co_await Bar();
+  }
+
+
+Options
+-------
+
+.. option:: RAIIDenyList
+
+   A semicolon-separated list of qualified types which should not be allowed to 
+   persist across suspension points.
+   Do not include `::` in the beginning of the qualified name.
+   Eg: `my::lockable; a::b; ::my::other::lockable;`
----------------
PiotrZSL wrote:

At info at the end about default value.

https://github.com/llvm/llvm-project/pull/68738