clang/test/CodeGenCoroutines/coro-cleanup.cpp

   1 // Verify that coroutine promise and allocated memory are freed up on exception.
   2 // RUN: %clang_cc1 -std=c++20 -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s
   3
   4 namespace std {
   5 template <typename... T> struct coroutine_traits;
   6
   7 template <class Promise = void> struct coroutine_handle {
   8   coroutine_handle() = default;
   9   static coroutine_handle from_address(void *) noexcept;
  10 };
  11 template <> struct coroutine_handle<void> {
  12   static coroutine_handle from_address(void *) noexcept;
  13   coroutine_handle() = default;
  14   template <class PromiseType>
  15   coroutine_handle(coroutine_handle<PromiseType>) noexcept;
  16 };
  17 } // namespace std
  18
  19 struct suspend_always {
  20   bool await_ready() noexcept;
  21   void await_suspend(std::coroutine_handle<>) noexcept;
  22   void await_resume() noexcept;
  23 };
  24
  25 template <> struct std::coroutine_traits<void> {
  26   struct promise_type {
  27     void get_return_object() noexcept;
  28     suspend_always initial_suspend() noexcept;
  29     suspend_always final_suspend() noexcept;
  30     void return_void() noexcept;
  31     promise_type();
  32     ~promise_type();
  33     void unhandled_exception() noexcept;
  34   };
  35 };
  36
  37 struct Cleanup { ~Cleanup(); };
  38 void may_throw();
  39
  40 // CHECK-LABEL: define{{.*}} void @_Z1fv(
  41 void f() {
  42   // CHECK: call noalias noundef nonnull ptr @_Znwm(i64
  43
  44   // If promise constructor throws, check that we free the memory.
  45
  46   // CHECK: invoke void @_ZNSt16coroutine_traitsIJvEE12promise_typeC1Ev(
  47   // CHECK-NEXT: to label %{{.+}} unwind label %[[DeallocPad:.+]]
  48
  49   // CHECK: [[DeallocPad]]:
  50   // CHECK-NEXT: landingpad
  51   // CHECK-NEXT:   cleanup
  52   // CHECK: br label %[[Dealloc:.+]]
  53
  54   Cleanup cleanup;
  55   may_throw();
  56
  57   // if may_throw throws, check that we destroy the promise and free the memory.
  58
  59   // CHECK: invoke void @_Z9may_throwv(
  60   // CHECK-NEXT: to label %{{.+}} unwind label %[[CatchPad:.+]]
  61
  62   // CHECK: [[CatchPad]]:
  63   // CHECK-NEXT:  landingpad
  64   // CHECK-NEXT:       catch ptr null
  65   // CHECK:  call void @_ZN7CleanupD1Ev(
  66   // CHECK:  br label %[[Catch:.+]]
  67
  68   // CHECK: [[Catch]]:
  69   // CHECK:    call ptr @__cxa_begin_catch(
  70   // CHECK:    call void @_ZNSt16coroutine_traitsIJvEE12promise_type19unhandled_exceptionEv(
  71   // CHECK:    invoke void @__cxa_end_catch()
  72   // CHECK-NEXT:    to label %[[Cont:.+]] unwind
  73
  74   // CHECK: [[Cont]]:
  75   // CHECK-NEXT: br label %[[Cont2:.+]]
  76   // CHECK: [[Cont2]]:
  77   // CHECK-NEXT: br label %[[Cleanup:.+]]
  78
  79   // CHECK: [[Cleanup]]:
  80   // CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_typeD1Ev(
  81   // CHECK: %[[Mem0:.+]] = call ptr @llvm.coro.free(
  82   // CHECK: call void @_ZdlPv(ptr noundef %[[Mem0]]
  83
  84   // CHECK: [[Dealloc]]:
  85   // CHECK:   %[[Mem:.+]] = call ptr @llvm.coro.free(
  86   // CHECK:   call void @_ZdlPv(ptr noundef %[[Mem]])
  87
  88   co_return;
  89 }
  90
  91 // CHECK-LABEL: define{{.*}} void @_Z1gv(
  92 void g() {
  93   for (;;)
  94     co_await suspend_always{};
  95   // Since this is the endless loop there should be no fallthrough handler (call to 'return_void').
  96   // CHECK-NOT: call void @_ZNSt16coroutine_traitsIJvEE12promise_type11return_voidEv
  97 }