1 files changed, 108 insertions, 0 deletions
diff --git a/test/CodeGenCoroutines/coro-await-resume-eh.cpp b/test/CodeGenCoroutines/coro-await-resume-eh.cpp
new file mode 100644
index 000000000000..f0f8855fbd4d
--- /dev/null
+++ b/test/CodeGenCoroutines/coro-await-resume-eh.cpp
@@ -0,0 +1,108 @@
+// Test the behavior of http://wg21.link/P0664, a proposal to catch any
+// exceptions thrown after the initial suspend point of a coroutine by
+// executing the handler specified by the promise type's 'unhandled_exception'
+// member function.
+//
+// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts \
+// RUN:   -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s \
+// RUN:   -fexceptions -fcxx-exceptions -disable-llvm-passes \
+// RUN:   | FileCheck %s
+
+#include "Inputs/coroutine.h"
+
+namespace coro = std::experimental::coroutines_v1;
+
+struct throwing_awaitable {
+  bool await_ready() { return true; }
+  void await_suspend(coro::coroutine_handle<>) {}
+  void await_resume() { throw 42; }
+};
+
+struct throwing_task {
+  struct promise_type {
+    auto get_return_object() { return throwing_task{}; }
+    auto initial_suspend() { return throwing_awaitable{}; }
+    auto final_suspend() { return coro::suspend_never{}; }
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+};
+
+// CHECK-LABEL: define void @_Z1fv()
+throwing_task f() {
+  // A variable RESUMETHREW is used to keep track of whether the body
+  // of 'await_resume' threw an exception. Exceptions thrown in
+  // 'await_resume' are unwound to RESUMELPAD.
+  // CHECK: init.ready:
+  // CHECK-NEXT: store i1 true, i1* %[[RESUMETHREW:.+]], align 1
+  // CHECK-NEXT: invoke void @_ZN18throwing_awaitable12await_resumeEv
+  // CHECK-NEXT: to label %[[RESUMECONT:.+]] unwind label %[[RESUMELPAD:.+]]
+
+  // If 'await_resume' does not throw an exception, 'false' is stored in
+  // variable RESUMETHREW.
+  // CHECK: [[RESUMECONT]]:
+  // CHECK-NEXT: store i1 false, i1* %[[RESUMETHREW]]
+  // CHECK-NEXT: br label %[[RESUMETRYCONT:.+]]
+
+  // 'unhandled_exception' is called for the exception thrown in
+  // 'await_resume'. The variable RESUMETHREW is never set to false,
+  // and a jump is made to RESUMETRYCONT.
+  // CHECK: [[RESUMELPAD]]:
+  // CHECK: br label %[[RESUMECATCH:.+]]
+  // CHECK: [[RESUMECATCH]]:
+  // CHECK: invoke void @_ZN13throwing_task12promise_type19unhandled_exceptionEv
+  // CHECK-NEXT: to label %[[RESUMEENDCATCH:.+]] unwind label
+  // CHECK: [[RESUMEENDCATCH]]:
+  // CHECK-NEXT: invoke void @__cxa_end_catch()
+  // CHECK-NEXT: to label %[[RESUMEENDCATCHCONT:.+]] unwind label
+  // CHECK: [[RESUMEENDCATCHCONT]]:
+  // CHECK-NEXT: br label %[[RESUMETRYCONT]]
+
+  // The variable RESUMETHREW is loaded and if true, then 'await_resume'
+  // threw an exception and the coroutine body is skipped, and the final
+  // suspend is executed immediately. Otherwise, the coroutine body is
+  // executed, and then the final suspend.
+  // CHECK: [[RESUMETRYCONT]]:
+  // CHECK-NEXT: %[[RESUMETHREWLOAD:.+]] = load i1, i1* %[[RESUMETHREW]]
+  // CHECK-NEXT: br i1 %[[RESUMETHREWLOAD]], label %[[RESUMEDCONT:.+]], label %[[RESUMEDBODY:.+]]
+
+  // CHECK: [[RESUMEDBODY]]:
+  // CHECK: invoke void @_ZN13throwing_task12promise_type11return_voidEv
+  // CHECK-NEXT: to label %[[REDUMEDBODYCONT:.+]] unwind label
+  // CHECK: [[REDUMEDBODYCONT]]:
+  // CHECK-NEXT: br label %[[COROFINAL:.+]]
+
+  // CHECK: [[RESUMEDCONT]]:
+  // CHECK-NEXT: br label %[[COROFINAL]]
+
+  // CHECK: [[COROFINAL]]:
+  // CHECK-NEXT: invoke void @_ZN13throwing_task12promise_type13final_suspendEv
+  co_return;
+}
+
+struct noexcept_awaitable {
+  bool await_ready() { return true; }
+  void await_suspend(coro::coroutine_handle<>) {}
+  void await_resume() noexcept {}
+};
+
+struct noexcept_task {
+  struct promise_type {
+    auto get_return_object() { return noexcept_task{}; }
+    auto initial_suspend() { return noexcept_awaitable{}; }
+    auto final_suspend() { return coro::suspend_never{}; }
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+};
+
+// CHECK-LABEL: define void @_Z1gv()
+noexcept_task g() {
+  // If the await_resume function is marked as noexcept, none of the additional
+  // conditions that are present in f() above are added to the IR.
+  // This means that no i1 are stored before or after calling await_resume:
+  // CHECK: init.ready:
+  // CHECK-NEXT: call void @_ZN18noexcept_awaitable12await_resumeEv
+  // CHECK-NOT: store i1 false, i1*
+  co_return;
+}