[coroutines] [NFC] Add tests for return_void, unhandled_exception and promise dtor

[GorNishanov]

Summary

• Test that coroutine promise destructor is called.
• Test that we call return_void on fallthrough
• Test that we call unhandled exception in a try catch surrounding the body

[GorNishanov]

LGTM

test/CodeGenCoroutines/Inputs/coroutine.h

+#pragma once
+
+namespace std { namespace experimental { inline namespace coroutines_v1 {
+
+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 { return ptr; }
+  void resume() const { __builtin_coro_resume(ptr); }
+  void destroy() const { __builtin_coro_destroy(ptr); }
+  bool done() const { return __builtin_coro_done(ptr); }
+  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;
+  }
+};
+
+  template <typename _PromiseT>
+  bool operator==(coroutine_handle<_PromiseT> const& _Left,
+    coroutine_handle<_PromiseT> const& _Right) noexcept
+  {
+    return _Left.address() == _Right.address();
+  }
+
+  template <typename _PromiseT>
+  bool operator!=(coroutine_handle<_PromiseT> const& _Left,
+    coroutine_handle<_PromiseT> const& _Right) noexcept
+  {
+    return !(_Left == _Right);
+  }
+
+struct suspend_always {
+  bool await_ready() { return false; }
+  void await_suspend(coroutine_handle<>) {}
+  void await_resume() {}
+};
+struct suspend_never {
+  bool await_ready() { return true; }
+  void await_suspend(coroutine_handle<>) {}
+  void await_resume() {}
+};
+
+}}}

test/CodeGenCoroutines/coro-promise-dtor.cpp

+// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts -triple=x86_64-pc-windows-msvc18.0.0 -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s
+// -triple=x86_64-unknown-linux-gnu
+
+#include "Inputs/coroutine.h"
+
+namespace coro = std::experimental::coroutines_v1;
+
+struct coro_t {
+  void* p;
+  ~coro_t();
+  struct promise_type {
+    coro_t get_return_object();
+    coro::suspend_never initial_suspend();
+    coro::suspend_never final_suspend();
+    void return_void();
+    promise_type();
+    ~promise_type();
+    void unhandled_exception();
+  };
+};
+
+struct Cleanup { ~Cleanup(); };
+void may_throw();
+
+coro_t f() {
+  Cleanup cleanup;
+  may_throw();
+  co_return;
+}
+
+// CHECK-LABEL: define void @"\01?f@@YA?AUcoro_t@@XZ"(
+// CHECK:  %gro.active = alloca i1
+// CHECK:  store i1 false, i1* %gro.active
+
+// CHECK:  invoke %"struct.coro_t::promise_type"* @"\01??0promise_type@coro_t@@QEAA@XZ"(
+// CHECK:  invoke void @"\01?get_return_object@promise_type@coro_t@@QEAA?AU2@XZ"(
+// CHECK:  store i1 true, i1* %gro.active
+
+// CHECK:  %[[IS_ACTIVE:.+]] = load i1, i1* %gro.active
+// CHECK:  br i1 %[[IS_ACTIVE]], label %[[CLEANUP1:.+]], label
+
+// CHECK: [[CLEANUP1]]:
+// CHECK:  %[[NRVO:.+]] = load i1, i1* %nrvo
+// CHECK:  br i1 %[[NRVO]], label %{{.+}}, label %[[DTOR:.+]]
+
+// CHECK: [[DTOR]]:
+// CHECK:  call void @"\01??_Dcoro_t@@QEAAXXZ"(

test/CodeGenCoroutines/coro-ret-void.cpp

+// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts -triple=x86_64-unknown-linux-gnu -emit-llvm %s -o - -disable-llvm-passes | FileCheck %s
+
+#include "Inputs/coroutine.h"
+
+namespace coro = std::experimental::coroutines_v1;
+
+struct coro1 {
+  struct promise_type {
+    coro1 get_return_object();
+    coro::suspend_never initial_suspend();
+    coro::suspend_never final_suspend();
+    void return_void();
+  };
+};
+
+coro1 f() {
+  co_await coro::suspend_never{};
+}
+
+// CHECK-LABEL: define void @_Z1fv(
+// CHECK: call void @_ZNSt12experimental13coroutines_v113suspend_never12await_resumeEv(%"struct.std::experimental::coroutines_v1::suspend_never"*
+// CHECK: call void @_ZN5coro112promise_type11return_voidEv(%"struct.coro1::promise_type"* %__promise)
+
+struct coro2 {
+  struct promise_type {
+    coro2 get_return_object();
+    coro::suspend_never initial_suspend();
+    coro::suspend_never final_suspend();
+    void return_value(int);
+  };
+};
+
+coro2 g() {
+  co_return 42;
+}
+
+// CHECK-LABEL: define void @_Z1gv(
+// CHECK: call void @_ZNSt12experimental13coroutines_v113suspend_never12await_resumeEv(%"struct.std::experimental::coroutines_v1::suspend_never"*
+// CHECK: call void @_ZN5coro212promise_type12return_valueEi(%"struct.coro2::promise_type"* %__promise, i32 42)

test/CodeGenCoroutines/coro-unhandled-exception.cpp

+// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts -triple=x86_64-pc-windows-msvc18.0.0 -emit-llvm %s -o - -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s
+// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck --check-prefix=CHECK-LPAD %s
+
+#include "Inputs/coroutine.h"
+
+namespace coro = std::experimental::coroutines_v1;
+
+namespace std {
+  using exception_ptr = int;
+  exception_ptr current_exception();
+}
+
+struct coro_t {
+  struct promise_type {
+    coro_t get_return_object() {
+      coro::coroutine_handle<promise_type>{};
+      return {};
+    }
+    coro::suspend_never initial_suspend() { return {}; }
+    coro::suspend_never final_suspend() { return {}; }
+    void return_void(){}
+    void unhandled_exception() noexcept;
+  };
+};
+
+struct Cleanup { ~Cleanup(); };
+void may_throw();
+
+coro_t f() {
+  Cleanup x;
+  may_throw();
+  co_return;
+}
+
+// CHECK: @"\01?f@@YA?AUcoro_t@@XZ"(
+// CHECK:   invoke void @"\01?may_throw@@YAXXZ"()
+// CHECK:       to label %{{.+}} unwind label %[[EHCLEANUP:.+]]
+// CHECK: [[EHCLEANUP]]:
+// CHECK:   %[[INNERPAD:.+]] = cleanuppad within none []
+// CHECK:   call void @"\01??_DCleanup@@QEAAXXZ"(
+// CHECK:   cleanupret from %[[INNERPAD]] unwind label %[[CATCHSW:.+]]
+// CHECK: [[CATCHSW]]:
+// CHECK:   %[[CATCHSWTOK:.+]] = catchswitch within none [label %[[CATCH:.+]]] unwind label
+// CHECK: [[CATCH]]:
+// CHECK:   %[[CATCHTOK:.+]] = catchpad within [[CATCHSWTOK:.+]]
+// CHECK:   call void @"\01?unhandled_exception@promise_type@coro_t@@QEAAXXZ"
+// CHECK:   catchret from %[[CATCHTOK]] to label %[[CATCHRETDEST:.+]]
+// CHECK: [[CATCHRETDEST]]:
+// CHECK-NEXT: br label %[[TRYCONT:.+]]
+// CHECK: [[TRYCONT]]:
+// CHECK-NEXT: br label %[[COROFIN:.+]]
+// CHECK: [[COROFIN]]:
+// CHECK-NEXT: invoke void @"\01?final_suspend@promise_type@coro_t@@QEAA?AUsuspend_never@coroutines_v1@experimental@std@@XZ"(
+
+// CHECK-LPAD: @_Z1fv(
+// CHECK-LPAD:   invoke void @_Z9may_throwv()
+// CHECK-LPAD:       to label %[[CONT:.+]] unwind label %[[CLEANUP:.+]]
+// CHECK-LPAD: [[CLEANUP]]:
+// CHECK-LPAD:   call void @_ZN7CleanupD1Ev(%struct.Cleanup* %x) #2
+// CHECK-LPAD:   br label %[[CATCH:.+]]
+
+// CHECK-LPAD: [[CATCH]]:
+// CHECK-LPAD:    call i8* @__cxa_begin_catch
+// CHECK-LPAD:    call void @_ZN6coro_t12promise_type19unhandled_exceptionEv(%"struct.coro_t::promise_type"* %__promise) #2
+// CHECK-LPAD:    invoke void @__cxa_end_catch()
+// CHECK-LPAD-NEXT:  to label %[[CATCHRETDEST:.+]] unwind label
+// CHECK-LPAD: [[CATCHRETDEST]]:
+// CHECK-LPAD-NEXT: br label %[[TRYCONT:.+]]
+// CHECK-LPAD: [[TRYCONT]]:
+// CHECK-LPAD-NEXT: br label %[[COROFIN:.+]]
+// CHECK-LPAD: [[COROFIN]]:
+// CHECK-LPAD-NEXT: invoke void @_ZN6coro_t12promise_type13final_suspendEv(