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

[Piotr Zegar via cfe-commits]

================
@@ -0,0 +1,131 @@
+// RUN: %check_clang_tidy -std=c++20 %s misc-coroutine-hostile-raii %t \
+// RUN:   -config="{CheckOptions: \
+// RUN:             {misc-coroutine-hostile-raii.RAIIDenyList: \
+// RUN:               'my::Mutex; ::my::other::Mutex'}}"
+
+namespace std {
+
+template <typename R, typename...> struct coroutine_traits {
+  using promise_type = typename R::promise_type;
+};
+
+template <typename Promise = void> struct coroutine_handle;
+
+template <> struct coroutine_handle<void> {
+  static coroutine_handle from_address(void *addr) noexcept {
+    coroutine_handle me;
+    me.ptr = addr;
+    return me;
+  }
+  void operator()() { resume(); }
+  void *address() const noexcept { return ptr; }
+  void resume() const {  }
+  void destroy() const { }
+  bool done() const { return true; }
+  coroutine_handle &operator=(decltype(nullptr)) {
+    ptr = nullptr;
+    return *this;
+  }
+  coroutine_handle(decltype(nullptr)) : ptr(nullptr) {}
+  coroutine_handle() : ptr(nullptr) {}
+  //  void reset() { ptr = nullptr; } // add to P0057?
+  explicit operator bool() const { return ptr; }
+
+protected:
+  void *ptr;
+};
+
+template <typename Promise> struct coroutine_handle : coroutine_handle<> {
+  using coroutine_handle<>::operator=;
+
+  static coroutine_handle from_address(void *addr) noexcept {
+    coroutine_handle me;
+    me.ptr = addr;
+    return me;
+  }
+
+  Promise &promise() const {
+    return *reinterpret_cast<Promise *>(
+        __builtin_coro_promise(ptr, alignof(Promise), false));
+  }
+  static coroutine_handle from_promise(Promise &promise) {
+    coroutine_handle p;
+    p.ptr = __builtin_coro_promise(&promise, alignof(Promise), true);
+    return p;
+  }
+};
+
+struct suspend_always {
+  bool await_ready() noexcept { return false; }
+  void await_suspend(std::coroutine_handle<>) noexcept {}
+  void await_resume() noexcept {}
+};
+} // namespace std
+
+struct ReturnObject {
+    struct promise_type {
+        ReturnObject get_return_object() { return {}; }
+        std::suspend_always initial_suspend() { return {}; }
+        std::suspend_always final_suspend() noexcept { return {}; }
+        void unhandled_exception() {}
+        std::suspend_always yield_value(int value) { return {}; }
+    };
+};
+
+
+#define SCOPED_LOCKABLE __attribute__ ((scoped_lockable))
+
+namespace absl {
+class SCOPED_LOCKABLE Mutex {};
+using Mutex2 = Mutex;
+} // namespace absl
+
+
+ReturnObject scopedLockableTest() {
+    absl::Mutex a;
+    // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: 'a' holds a lock across a suspension point of coroutine and could be unlocked by a different thread [misc-coroutine-hostile-raii]
+    absl::Mutex2 b;
+    // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: 'b' holds a lock across a suspension point of coroutine and could be unlocked by a different thread [misc-coroutine-hostile-raii]
+    {
+        absl::Mutex no_warning_1;
+        { absl::Mutex no_warning_2; }
+    }
+
+    co_yield 1;
+    absl::Mutex c;
+    // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: 'c' holds a lock across a suspension point of coroutine and could be unlocked by a different thread [misc-coroutine-hostile-raii]
+    co_await std::suspend_always{};
+    for(int i=1;i<=10;++i ) {
+      absl::Mutex d;
+      // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: 'd' holds a lock across a suspension point of coroutine and could be unlocked by a different thread [misc-coroutine-hostile-raii]
+      co_await std::suspend_always{};
+      co_yield 1;
+      absl::Mutex no_warning_3;
+    }
+    if (true) {
+      absl::Mutex e;
+      // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: 'e' holds a lock across a suspension point of coroutine and could be unlocked by a different thread [misc-coroutine-hostile-raii]
+      co_yield 1;
+      absl::Mutex no_warning_4;
+    }
+    absl::Mutex no_warning_5;
+}
+namespace my {
+class Mutex{};
+
+namespace other {
+class Mutex{};
+} // namespace other
+
+using Mutex2 = Mutex;
+} // namespace my
+
+ReturnObject denyListTest() {
+    my::Mutex a;
+    // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: 'a' persists across a suspension point of coroutine [misc-coroutine-hostile-raii]
+    my::other::Mutex b;
+    // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: 'b' persists across a suspension point of coroutine [misc-coroutine-hostile-raii]
+    my::Mutex2 c;
+    // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: 'c' persists across a suspension point of coroutine [misc-coroutine-hostile-raii]
+    co_yield 1;
+}
----------------
PiotrZSL wrote:

add explicit test with mutex being on higher level:
```
{
   mutex mtx;

   {
       co_yield ;
   }
}
```

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