1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
// This is reduced test case from https://github.com/llvm/llvm-project/issues/59723.
// This is not a minimal reproducer intentionally to check the compiler's ability.
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -fcxx-exceptions\
// RUN: -fexceptions -O2 -emit-llvm %s -o - | FileCheck %s
#include "Inputs/coroutine.h"
// executor and operation base
class bug_any_executor;
struct bug_async_op_base
{
void invoke();
protected:
~bug_async_op_base() = default;
};
class bug_any_executor
{
using op_type = bug_async_op_base;
public:
virtual ~bug_any_executor() = default;
// removing noexcept enables clang to find that the pointer has escaped
virtual void post(op_type& op) noexcept = 0;
virtual void wait() noexcept = 0;
};
class bug_thread_executor : public bug_any_executor
{
public:
void start()
{
}
~bug_thread_executor()
{
}
// although this implementation is not realy noexcept due to allocation but I have a real one that is and required to be noexcept
virtual void post(bug_async_op_base& op) noexcept override;
virtual void wait() noexcept override
{
}
};
// task and promise
struct bug_final_suspend_notification
{
virtual std::coroutine_handle<> get_waiter() = 0;
};
class bug_task;
class bug_task_promise
{
friend bug_task;
public:
bug_task get_return_object() noexcept;
constexpr std::suspend_always initial_suspend() noexcept { return {}; }
std::suspend_always final_suspend() noexcept
{
return {};
}
void unhandled_exception() noexcept;
constexpr void return_void() const noexcept {}
void get_result() const
{
}
};
template <class T, class U>
T exchange(T &&t, U &&u) {
T ret = t;
t = u;
return ret;
}
class bug_task
{
friend bug_task_promise;
using handle = std::coroutine_handle<>;
using promise_t = bug_task_promise;
bug_task(handle coro, promise_t* p) noexcept : this_coro{ coro }, this_promise{ p }
{
}
public:
using promise_type = bug_task_promise;
bug_task(bug_task&& other) noexcept
: this_coro{ exchange(other.this_coro, nullptr) }, this_promise{ exchange(other.this_promise, nullptr) } {
}
~bug_task()
{
if (this_coro)
this_coro.destroy();
}
constexpr bool await_ready() const noexcept
{
return false;
}
handle await_suspend(handle waiter) noexcept
{
return this_coro;
}
void await_resume()
{
return this_promise->get_result();
}
handle this_coro;
promise_t* this_promise;
};
bug_task bug_task_promise::get_return_object() noexcept
{
return { std::coroutine_handle<bug_task_promise>::from_promise(*this), this };
}
// spawn operation and spawner
template<class Handler>
class bug_spawn_op final : public bug_async_op_base, bug_final_suspend_notification
{
Handler handler;
bug_task task_;
public:
bug_spawn_op(Handler handler, bug_task&& t)
: handler { handler }, task_{ static_cast<bug_task&&>(t) } {}
virtual std::coroutine_handle<> get_waiter() override
{
handler();
return std::noop_coroutine();
}
};
class bug_spawner;
struct bug_spawner_awaiter
{
bug_spawner& s;
std::coroutine_handle<> waiter;
bug_spawner_awaiter(bug_spawner& s) : s{ s } {}
bool await_ready() const noexcept;
void await_suspend(std::coroutine_handle<> coro);
void await_resume() {}
};
class bug_spawner
{
friend bug_spawner_awaiter;
struct final_handler_t
{
bug_spawner& s;
void operator()()
{
s.awaiter_->waiter.resume();
}
};
public:
bug_spawner(bug_any_executor& ex) : ex_{ ex } {}
void spawn(bug_task&& t) {
using op_t = bug_spawn_op<final_handler_t>;
// move task into ptr
op_t* ptr = new op_t(final_handler_t{ *this }, static_cast<bug_task&&>(t));
++count_;
ex_.post(*ptr); // ptr escapes here thus task escapes but clang can't deduce that unless post() is not noexcept
}
bug_spawner_awaiter wait() noexcept { return { *this }; }
private:
bug_any_executor& ex_; // if bug_thread_executor& is used instead enables clang to detect the escape of the promise
bug_spawner_awaiter* awaiter_ = nullptr;
unsigned count_ = 0;
};
// test case
bug_task bug_spawned_task(int id, int inc)
{
co_return;
}
struct A {
A();
};
void throwing_fn(bug_spawner& s) {
s.spawn(bug_spawned_task(1, 2));
throw A{};
}
// Check that the coroutine frame of bug_spawned_task are allocated from operator new.
// CHECK: define{{.*}}@_Z11throwing_fnR11bug_spawner
// CHECK-NOT: alloc
// CHECK: %[[CALL:.+]] = {{.*}}@_Znwm(i64{{.*}} 24)
// CHECK: store ptr @_Z16bug_spawned_taskii.resume, ptr %[[CALL]]
|