Add the ability to exempt callees from the misc-coroutine-hostile-raii clang-tidy check (#167778)

Author: higher-performance

clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.cpp

@@ -73,15 +73,19 @@ CoroutineHostileRAIICheck::CoroutineHostileRAIICheck(StringRef Name,
       RAIITypesList(utils::options::parseStringList(
           Options.get("RAIITypesList", "std::lock_guard;std::scoped_lock"))),
       AllowedAwaitablesList(utils::options::parseStringList(
-          Options.get("AllowedAwaitablesList", ""))) {}
+          Options.get("AllowedAwaitablesList", ""))),
+      AllowedCallees(
+          utils::options::parseStringList(Options.get("AllowedCallees", ""))) {}
 
 void CoroutineHostileRAIICheck::registerMatchers(MatchFinder *Finder) {
   // A suspension happens with co_await or co_yield.
   auto ScopedLockable = varDecl(hasType(hasCanonicalType(hasDeclaration(
                                     hasAttr(attr::Kind::ScopedLockable)))))
                             .bind("scoped-lockable");
   auto OtherRAII = varDecl(typeWithNameIn(RAIITypesList)).bind("raii");
-  auto AllowedSuspend = awaitable(typeWithNameIn(AllowedAwaitablesList));
+  auto AllowedSuspend = awaitable(
+      anyOf(typeWithNameIn(AllowedAwaitablesList),
+            callExpr(callee(functionDecl(hasAnyName(AllowedCallees))))));
   Finder->addMatcher(
       expr(anyOf(coawaitExpr(unless(AllowedSuspend)), coyieldExpr()),
            forEachPrevStmt(
@@ -111,5 +115,7 @@ void CoroutineHostileRAIICheck::storeOptions(
                 utils::options::serializeStringList(RAIITypesList));
   Options.store(Opts, "SafeAwaitableList",
                 utils::options::serializeStringList(AllowedAwaitablesList));
+  Options.store(Opts, "SafeCallees",
+                utils::options::serializeStringList(AllowedCallees));
 }
 } // namespace clang::tidy::misc

clang-tools-extra/clang-tidy/misc/CoroutineHostileRAIICheck.h

@@ -46,6 +46,9 @@ class CoroutineHostileRAIICheck : public ClangTidyCheck {
   // List of fully qualified awaitable types which are considered safe to
   // co_await.
   std::vector<StringRef> AllowedAwaitablesList;
+  // List of callees whose return values are considered safe to directly
+  // co_await.
+  std::vector<StringRef> AllowedCallees;
 };
 
 } // namespace clang::tidy::misc

clang-tools-extra/docs/ReleaseNotes.rst

@@ -423,6 +423,11 @@ Changes in existing checks
   positives on return of non-const pointer and fix false positives on
   pointer-to-member operator.
 
+- Improved :doc:`misc-coroutine-hostile-raii
+  <clang-tidy/checks/misc/coroutine-hostile-raii>` check by adding the option
+  `AllowedCallees`, that allows exempting safely awaitable callees from the
+  check.
+
 - Improved :doc:`misc-header-include-cycle
   <clang-tidy/checks/misc/header-include-cycle>` check performance.
 

clang-tools-extra/docs/clang-tidy/checks/misc/coroutine-hostile-raii.rst

@@ -81,3 +81,23 @@ Options
     Eg: `my::safe::awaitable;other::awaitable`
     Default is an empty string.
 
+.. option:: AllowedCallees
+
+    A semicolon-separated list of callee function names which can
+    be safely awaited while having hostile RAII objects in scope.
+    Example usage:
+
+    .. code-block:: c++
+
+      // Consider option AllowedCallees = "noop"
+      task noop() { co_return; }
+
+      task coro() {
+        // This persists across the co_await but is not flagged
+        // because the awaitable is considered safe to await on.
+        const std::lock_guard l(&mu_);
+        co_await noop();
+      }
+
+    Eg: `my::safe::await;other::await`
+    Default is an empty string.

clang-tools-extra/test/clang-tidy/checkers/misc/coroutine-hostile-raii.cpp

@@ -1,7 +1,8 @@
 // RUN: %check_clang_tidy -std=c++20 %s misc-coroutine-hostile-raii %t \
 // RUN:   -config="{CheckOptions: {\
 // RUN:             misc-coroutine-hostile-raii.RAIITypesList: 'my::Mutex; ::my::other::Mutex', \
-// RUN:             misc-coroutine-hostile-raii.AllowedAwaitablesList: 'safe::awaitable; ::transformable::awaitable' \
+// RUN:             misc-coroutine-hostile-raii.AllowedAwaitablesList: 'safe::awaitable; ::transformable::awaitable', \
+// RUN:             misc-coroutine-hostile-raii.AllowedCallees: 'safe::AwaitFunc; ::safe::Obj::AwaitMethod' \
 // RUN:             }}"
 
 namespace std {
@@ -145,12 +146,18 @@ namespace safe {
   void await_suspend(std::coroutine_handle<>) noexcept {}
   void await_resume() noexcept {}
 };
+  std::suspend_always AwaitFunc();
+  struct Obj {
+    std::suspend_always AwaitMethod();
+  };
 } // namespace safe
 ReturnObject RAIISafeSuspendTest() {
   absl::Mutex a;
   co_await safe::awaitable{};
   using other = safe::awaitable;
   co_await other{};
+  co_await safe::AwaitFunc();
+  co_await safe::Obj().AwaitMethod();
 } 
 
 // ================================================================================