Author: Xun Li Date: 2020-06-25T10:49:50-07:00 New Revision: 366159566df3a980d3e34f3ec9609e77cdb4df8b
URL: https://github.com/llvm/llvm-project/commit/366159566df3a980d3e34f3ec9609e77cdb4df8b DIFF: https://github.com/llvm/llvm-project/commit/366159566df3a980d3e34f3ec9609e77cdb4df8b.diff LOG: [Coroutines] Special handle __builtin_coro_resume for final_suspend nothrow check Summary: In https://reviews.llvm.org/D82029 we added the conformance check that the expression co_await promise.final_suspend() should not potentially throw. As part of this expression, in cases when the await_suspend() method of the final suspend awaiter returns a handle, __builtin_coro_resume could be called on the handle to immediately resume that coroutine. __builtin_coro_resume is not declared with noexcept and it shouldn't. We need to special check this case here. Reviewers: modocache, lewissbaker, junparser Reviewed By: lewissbaker Subscribers: modocache, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D82415 Added: Modified: clang/lib/Sema/SemaCoroutine.cpp Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp index c8ca247aae83..6262f4b117d3 100644 --- a/clang/lib/Sema/SemaCoroutine.cpp +++ b/clang/lib/Sema/SemaCoroutine.cpp @@ -614,6 +614,17 @@ static void checkNoThrow(Sema &S, const Stmt *E, // In the case of dtor, the call to dtor is implicit and hence we should // pass nullptr to canCalleeThrow. if (Sema::canCalleeThrow(S, IsDtor ? nullptr : cast<Expr>(E), D)) { + if (const auto *FD = dyn_cast<FunctionDecl>(D)) { + // co_await promise.final_suspend() could end up calling + // __builtin_coro_resume for symmetric transfer if await_suspend() + // returns a handle. In that case, even __builtin_coro_resume is not + // declared as noexcept and may throw, it does not throw _into_ the + // coroutine that just suspended, but rather throws back out from + // whoever called coroutine_handle::resume(), hence we claim that + // logically it does not throw. + if (FD->getBuiltinID() == Builtin::BI__builtin_coro_resume) + return; + } if (ThrowingDecls.empty()) { // First time seeing an error, emit the error message. S.Diag(cast<FunctionDecl>(S.CurContext)->getLocation(), _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits