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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [coroutines] ASan reports stack-use-after-scope when coroutine allocation is elided"
href="https://bugs.llvm.org/show_bug.cgi?id=47767">47767</a>
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<th>Summary</th>
<td>[coroutines] ASan reports stack-use-after-scope when coroutine allocation is elided
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++2a
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>erik@olofsson.info
</td>
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<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
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<pre>This happens when the coroutine frame allocation is elided and the promise
constructor is not inlined. See: <a href="https://godbolt.org/z/8EzP7a">https://godbolt.org/z/8EzP7a</a>
// -std=c++20 -stdlib=libc++ -O3 -g -fcoroutines-ts -fsanitize=address
-fsanitize-address-use-after-scope
#include <experimental/coroutine>
#define inline_never __attribute__((noinline))
#define inline_always inline __attribute__((always_inline))
template <typename T>
class co;
using suspend_never = std::experimental::suspend_never;
template <typename T>
class promise;
template <>
struct promise <void>
{
int member = 0;
inline_never promise()
{
}
~promise()
{
}
co<void> get_return_object() noexcept;
void return_void() noexcept
{
};
suspend_never initial_suspend() noexcept
{
return {};
}
void unhandled_exception() noexcept
{
}
suspend_never final_suspend() noexcept
{
return {};
}
};
template <typename T = void>
struct co
{
using promise_type = promise<T>;
~co()
{
}
};
inline_always co<void> promise<void>::get_return_object() noexcept {
return co<void>();
}
inline_never co<> bar() {
co_return;
}
int main() {
bar();
return 0;
}</pre>
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