Partially tested on Linux-x64, will run full suite on Linux-PPC64.
2018-02-28 Ville Voutilainen <ville.voutilai...@gmail.com>
PR libstdc++/84601
* include/std/optional (_Optional_payload): Split into multiple
specializations that can handle different cases of trivial or
non-trivial assignment operators.
* testsuite/20_util/optional/84601.cc: New.
diff --git a/libstdc++-v3/include/std/optional
b/libstdc++-v3/include/std/optional
index 01fc06b..0aa20dd 100644
--- a/libstdc++-v3/include/std/optional
+++ b/libstdc++-v3/include/std/optional
@@ -98,13 +98,137 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
- // Payload for constexpr optionals.
+ // Payload for optionals with non-trivial destructor.
template <typename _Tp,
bool /*_HasTrivialDestructor*/ =
- is_trivially_destructible<_Tp>::value>
+ is_trivially_destructible<_Tp>::value,
+ bool /*_HasTrivialCopyAssignment*/ =
+ is_trivially_copy_assignable<_Tp>::value,
+ bool /*_HasTrivialMoveAssignment*/ =
+ is_trivially_move_assignable<_Tp>::value>
struct _Optional_payload
{
constexpr _Optional_payload()
+ : _M_empty() {}
+
+ template <typename... _Args>
+ constexpr _Optional_payload(in_place_t, _Args&&... __args)
+ : _M_payload(std::forward<_Args>(__args)...),
+ _M_engaged(true) {}
+
+ template<typename _Up, typename... _Args>
+ constexpr _Optional_payload(std::initializer_list<_Up> __il,
+ _Args&&... __args)
+ : _M_payload(__il, std::forward<_Args>(__args)...),
+ _M_engaged(true) {}
+ constexpr
+ _Optional_payload(bool __engaged, const _Optional_payload& __other)
+ : _Optional_payload(__other)
+ {}
+
+ constexpr
+ _Optional_payload(bool __engaged, _Optional_payload&& __other)
+ : _Optional_payload(std::move(__other))
+ {}
+
+ constexpr _Optional_payload(const _Optional_payload& __other)
+ {
+ if (__other._M_engaged)
+ this->_M_construct(__other._M_payload);
+ }
+
+ constexpr _Optional_payload(_Optional_payload&& __other)
+ {
+ if (__other._M_engaged)
+ this->_M_construct(std::move(__other._M_payload));
+ }
+
+ _Optional_payload&
+ operator=(const _Optional_payload& __other)
+ {
+ if (this->_M_engaged && __other._M_engaged)
+ this->_M_get() = __other._M_get();
+ else
+ {
+ if (__other._M_engaged)
+ this->_M_construct(__other._M_get());
+ else
+ this->_M_reset();
+ }
+ return *this;
+ }
+
+ _Optional_payload&
+ operator=(_Optional_payload&& __other)
+ noexcept(__and_<is_nothrow_move_constructible<_Tp>,
+ is_nothrow_move_assignable<_Tp>>())
+ {
+ if (this->_M_engaged && __other._M_engaged)
+ this->_M_get() = std::move(__other._M_get());
+ else
+ {
+ if (__other._M_engaged)
+ this->_M_construct(std::move(__other._M_get()));
+ else
+ this->_M_reset();
+ }
+ return *this;
+ }
+
+ using _Stored_type = remove_const_t<_Tp>;
+ struct _Empty_byte { };
+ union {
+ _Empty_byte _M_empty;
+ _Stored_type _M_payload;
+ };
+ bool _M_engaged = false;
+
+ ~_Optional_payload()
+ {
+ if (_M_engaged)
+ _M_payload.~_Stored_type();
+ }
+
+ template<typename... _Args>
+ void
+ _M_construct(_Args&&... __args)
+ noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
+ {
+ ::new ((void *) std::__addressof(this->_M_payload))
+ _Stored_type(std::forward<_Args>(__args)...);
+ this->_M_engaged = true;
+ }
+
+ // The _M_get operations have _M_engaged as a precondition.
+ constexpr _Tp&
+ _M_get() noexcept
+ {
+ return this->_M_payload;
+ }
+
+ constexpr const _Tp&
+ _M_get() const noexcept
+ {
+ return this->_M_payload;
+ }
+
+ // _M_reset is a 'safe' operation with no precondition.
+ void
+ _M_reset() noexcept
+ {
+ if (this->_M_engaged)
+ {
+ this->_M_engaged = false;
+ this->_M_payload.~_Stored_type();
+ }
+ }
+ };
+
+ // Payload for constexpr optionals.
+ template <typename _Tp>
+ struct _Optional_payload<_Tp, true, true, true>
+ {
+ constexpr _Optional_payload()
: _M_empty(), _M_engaged(false) {}
template<typename... _Args>
@@ -161,44 +285,294 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool _M_engaged;
};
- // Payload for optionals with non-trivial destructor.
+ // Payload for optionals with non-trivial copy assignment.
template <typename _Tp>
- struct _Optional_payload<_Tp, false>
+ struct _Optional_payload<_Tp, true, false, true>
{
constexpr _Optional_payload()
- : _M_empty() {}
+ : _M_empty(), _M_engaged(false) {}
- template <typename... _Args>
+ template<typename... _Args>
constexpr _Optional_payload(in_place_t, _Args&&... __args)
: _M_payload(std::forward<_Args>(__args)...),
+ _M_engaged(true)
+ {}
+
+ template<typename _Up, typename... _Args>
+ constexpr _Optional_payload(std::initializer_list<_Up> __il,
+ _Args&&... __args)
+ : _M_payload(__il, std::forward<_Args>(__args)...),
_M_engaged(true) {}
+ template <class _Up> struct __ctor_tag {};
+
+ constexpr _Optional_payload(__ctor_tag<bool>,
+ const _Tp& __other)
+ : _M_payload(__other),
+ _M_engaged(true)
+ {}
+
+ constexpr _Optional_payload(__ctor_tag<void>)
+ : _M_empty(), _M_engaged(false)
+ {}
+
+ constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
+ : _M_payload(std::move(__other)),
+ _M_engaged(true)
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ const _Optional_payload& __other)
+ : _Optional_payload(__engaged ?
+ _Optional_payload(__ctor_tag<bool>{},
+ __other._M_payload) :
+ _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ _Optional_payload&& __other)
+ : _Optional_payload(__engaged
+ ? _Optional_payload(__ctor_tag<bool>{},
+ std::move(__other._M_payload))
+ : _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ _Optional_payload(const _Optional_payload&) = default;
+ _Optional_payload(_Optional_payload&&) = default;
+
+ _Optional_payload&
+ operator=(const _Optional_payload& __other)
+ {
+ if (this->_M_engaged && __other._M_engaged)
+ this->_M_get() = __other._M_get();
+ else
+ {
+ if (__other._M_engaged)
+ this->_M_construct(__other._M_get());
+ else
+ this->_M_reset();
+ }
+ return *this;
+ }
+
+ _Optional_payload&
+ operator=(_Optional_payload&& __other) = default;
+
+ using _Stored_type = remove_const_t<_Tp>;
+ struct _Empty_byte { };
+ union {
+ _Empty_byte _M_empty;
+ _Stored_type _M_payload;
+ };
+ bool _M_engaged;
+
+ template<typename... _Args>
+ void
+ _M_construct(_Args&&... __args)
+ noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
+ {
+ ::new ((void *) std::__addressof(this->_M_payload))
+ _Stored_type(std::forward<_Args>(__args)...);
+ this->_M_engaged = true;
+ }
+
+ // The _M_get operations have _M_engaged as a precondition.
+ constexpr _Tp&
+ _M_get() noexcept
+ {
+ return this->_M_payload;
+ }
+
+ constexpr const _Tp&
+ _M_get() const noexcept
+ {
+ return this->_M_payload;
+ }
+
+ // _M_reset is a 'safe' operation with no precondition.
+ void
+ _M_reset() noexcept
+ {
+ if (this->_M_engaged)
+ {
+ this->_M_engaged = false;
+ this->_M_payload.~_Stored_type();
+ }
+ }
+ };
+
+ // Payload for optionals with non-trivial move assignment.
+ template <typename _Tp>
+ struct _Optional_payload<_Tp, true, true, false>
+ {
+ constexpr _Optional_payload()
+ : _M_empty(), _M_engaged(false) {}
+
+ template<typename... _Args>
+ constexpr _Optional_payload(in_place_t, _Args&&... __args)
+ : _M_payload(std::forward<_Args>(__args)...),
+ _M_engaged(true)
+ {}
+
template<typename _Up, typename... _Args>
constexpr _Optional_payload(std::initializer_list<_Up> __il,
_Args&&... __args)
: _M_payload(__il, std::forward<_Args>(__args)...),
_M_engaged(true) {}
- constexpr
- _Optional_payload(bool __engaged, const _Optional_payload& __other)
- : _Optional_payload(__other)
+
+ template <class _Up> struct __ctor_tag {};
+
+ constexpr _Optional_payload(__ctor_tag<bool>,
+ const _Tp& __other)
+ : _M_payload(__other),
+ _M_engaged(true)
{}
- constexpr
- _Optional_payload(bool __engaged, _Optional_payload&& __other)
- : _Optional_payload(std::move(__other))
+ constexpr _Optional_payload(__ctor_tag<void>)
+ : _M_empty(), _M_engaged(false)
{}
- constexpr _Optional_payload(const _Optional_payload& __other)
+ constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
+ : _M_payload(std::move(__other)),
+ _M_engaged(true)
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ const _Optional_payload& __other)
+ : _Optional_payload(__engaged ?
+ _Optional_payload(__ctor_tag<bool>{},
+ __other._M_payload) :
+ _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ _Optional_payload&& __other)
+ : _Optional_payload(__engaged
+ ? _Optional_payload(__ctor_tag<bool>{},
+ std::move(__other._M_payload))
+ : _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ _Optional_payload(const _Optional_payload&) = default;
+ _Optional_payload(_Optional_payload&&) = default;
+
+ _Optional_payload&
+ operator=(const _Optional_payload& __other) = default;
+
+ _Optional_payload&
+ operator=(_Optional_payload&& __other)
+ noexcept(__and_<is_nothrow_move_constructible<_Tp>,
+ is_nothrow_move_assignable<_Tp>>())
{
- if (__other._M_engaged)
- this->_M_construct(__other._M_payload);
+ if (this->_M_engaged && __other._M_engaged)
+ this->_M_get() = std::move(__other._M_get());
+ else
+ {
+ if (__other._M_engaged)
+ this->_M_construct(std::move(__other._M_get()));
+ else
+ this->_M_reset();
+ }
+ return *this;
}
- constexpr _Optional_payload(_Optional_payload&& __other)
+ using _Stored_type = remove_const_t<_Tp>;
+ struct _Empty_byte { };
+ union {
+ _Empty_byte _M_empty;
+ _Stored_type _M_payload;
+ };
+ bool _M_engaged;
+
+ template<typename... _Args>
+ void
+ _M_construct(_Args&&... __args)
+ noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
+ {
+ ::new ((void *) std::__addressof(this->_M_payload))
+ _Stored_type(std::forward<_Args>(__args)...);
+ this->_M_engaged = true;
+ }
+
+ // The _M_get operations have _M_engaged as a precondition.
+ constexpr _Tp&
+ _M_get() noexcept
{
- if (__other._M_engaged)
- this->_M_construct(std::move(__other._M_payload));
+ return this->_M_payload;
+ }
+
+ constexpr const _Tp&
+ _M_get() const noexcept
+ {
+ return this->_M_payload;
+ }
+
+ // _M_reset is a 'safe' operation with no precondition.
+ void
+ _M_reset() noexcept
+ {
+ if (this->_M_engaged)
+ {
+ this->_M_engaged = false;
+ this->_M_payload.~_Stored_type();
+ }
}
+ };
+
+ // Payload for optionals with non-trivial copy and move assignment.
+ template <typename _Tp>
+ struct _Optional_payload<_Tp, true, false, false>
+ {
+ constexpr _Optional_payload()
+ : _M_empty(), _M_engaged(false) {}
+
+ template<typename... _Args>
+ constexpr _Optional_payload(in_place_t, _Args&&... __args)
+ : _M_payload(std::forward<_Args>(__args)...),
+ _M_engaged(true)
+ {}
+
+ template<typename _Up, typename... _Args>
+ constexpr _Optional_payload(std::initializer_list<_Up> __il,
+ _Args&&... __args)
+ : _M_payload(__il, std::forward<_Args>(__args)...),
+ _M_engaged(true) {}
+
+ template <class _Up> struct __ctor_tag {};
+
+ constexpr _Optional_payload(__ctor_tag<bool>,
+ const _Tp& __other)
+ : _M_payload(__other),
+ _M_engaged(true)
+ {}
+
+ constexpr _Optional_payload(__ctor_tag<void>)
+ : _M_empty(), _M_engaged(false)
+ {}
+
+ constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
+ : _M_payload(std::move(__other)),
+ _M_engaged(true)
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ const _Optional_payload& __other)
+ : _Optional_payload(__engaged ?
+ _Optional_payload(__ctor_tag<bool>{},
+ __other._M_payload) :
+ _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ constexpr _Optional_payload(bool __engaged,
+ _Optional_payload&& __other)
+ : _Optional_payload(__engaged
+ ? _Optional_payload(__ctor_tag<bool>{},
+ std::move(__other._M_payload))
+ : _Optional_payload(__ctor_tag<void>{}))
+ {}
+
+ _Optional_payload(const _Optional_payload&) = default;
+ _Optional_payload(_Optional_payload&&) = default;
_Optional_payload&
operator=(const _Optional_payload& __other)
@@ -238,13 +612,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Empty_byte _M_empty;
_Stored_type _M_payload;
};
- bool _M_engaged = false;
-
- ~_Optional_payload()
- {
- if (_M_engaged)
- _M_payload.~_Stored_type();
- }
+ bool _M_engaged;
template<typename... _Args>
void
@@ -280,7 +648,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
};
-
+
template<typename _Tp, typename _Dp>
class _Optional_base_impl
{
diff --git a/libstdc++-v3/testsuite/20_util/optional/84601.cc
b/libstdc++-v3/testsuite/20_util/optional/84601.cc
new file mode 100644
index 0000000..e86d39e
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/optional/84601.cc
@@ -0,0 +1,22 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile }
+
+#include <optional>
+
+using pair_t = std::pair<int, int>;
+using opt_t = std::optional<pair_t>;
+
+static_assert(std::is_copy_constructible_v<opt_t::value_type>);
+static_assert(std::is_copy_assignable_v<opt_t::value_type>);
+
+static_assert(std::is_copy_assignable_v<opt_t>); // assertion fails.
+
+class A
+{
+ void f(const opt_t& opt)
+ {
+ _opt = opt;
+ }
+
+ opt_t _opt;
+};
