[llvm-branch-commits] [libcxx] 0a12742 - [libc++] Fix UB in <expected> related to "has value" flag (#68552) (#68733)
Tobias Hieta via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Nov 14 00:28:36 PST 2023
Author: Jan Kokemüller
Date: 2023-11-14T09:22:23+01:00
New Revision: 0a1274224ef8928507b8e50c19ea25e62a7a3bf3
URL: https://github.com/llvm/llvm-project/commit/0a1274224ef8928507b8e50c19ea25e62a7a3bf3
DIFF: https://github.com/llvm/llvm-project/commit/0a1274224ef8928507b8e50c19ea25e62a7a3bf3.diff
LOG: [libc++] Fix UB in <expected> related to "has value" flag (#68552) (#68733)
The calls to std::construct_at might overwrite the previously set
__has_value_ flag in the case where the flag is overlapping with
the actual value or error being stored (since we use [[no_unique_address]]).
To fix this issue, this patch ensures that we initialize the
__has_value_ flag after we call std::construct_at.
Fixes #68552
(cherry picked from commit 134c91595568ea1335b22e559f20c1a488ea270e)
Added:
Modified:
libcxx/include/__expected/expected.h
libcxx/test/std/utilities/expected/expected.expected/assign/emplace.intializer_list.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/assign/emplace.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.move.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.default.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace_init_list.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.move.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.u.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect_init_list.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.move.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/observers/has_value.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/swap/free.swap.pass.cpp
libcxx/test/std/utilities/expected/expected.expected/swap/member.swap.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.move.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.move.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect_init_list.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.copy.pass.cpp
libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.move.pass.cpp
libcxx/test/std/utilities/expected/expected.void/observers/has_value.pass.cpp
libcxx/test/std/utilities/expected/expected.void/swap/free.swap.pass.cpp
libcxx/test/std/utilities/expected/expected.void/swap/member.swap.pass.cpp
libcxx/test/std/utilities/expected/types.h
Removed:
################################################################################
diff --git a/libcxx/include/__expected/expected.h b/libcxx/include/__expected/expected.h
index 7d57aa4db5f952f..5836600312de169 100644
--- a/libcxx/include/__expected/expected.h
+++ b/libcxx/include/__expected/expected.h
@@ -119,9 +119,7 @@ class expected {
_LIBCPP_HIDE_FROM_ABI constexpr expected()
noexcept(is_nothrow_default_constructible_v<_Tp>) // strengthened
requires is_default_constructible_v<_Tp>
- : __has_val_(true) {
- std::construct_at(std::addressof(__union_.__val_));
- }
+ : __union_(std::in_place), __has_val_(true) {}
_LIBCPP_HIDE_FROM_ABI constexpr expected(const expected&) = delete;
@@ -136,14 +134,7 @@ class expected {
noexcept(is_nothrow_copy_constructible_v<_Tp> && is_nothrow_copy_constructible_v<_Err>) // strengthened
requires(is_copy_constructible_v<_Tp> && is_copy_constructible_v<_Err> &&
!(is_trivially_copy_constructible_v<_Tp> && is_trivially_copy_constructible_v<_Err>))
- : __has_val_(__other.__has_val_) {
- if (__has_val_) {
- std::construct_at(std::addressof(__union_.__val_), __other.__union_.__val_);
- } else {
- std::construct_at(std::addressof(__union_.__unex_), __other.__union_.__unex_);
- }
- }
-
+ : __union_(__other.__has_val_, __other.__union_), __has_val_(__other.__has_val_) { }
_LIBCPP_HIDE_FROM_ABI constexpr expected(expected&&)
requires(is_move_constructible_v<_Tp> && is_move_constructible_v<_Err>
@@ -154,13 +145,7 @@ class expected {
noexcept(is_nothrow_move_constructible_v<_Tp> && is_nothrow_move_constructible_v<_Err>)
requires(is_move_constructible_v<_Tp> && is_move_constructible_v<_Err> &&
!(is_trivially_move_constructible_v<_Tp> && is_trivially_move_constructible_v<_Err>))
- : __has_val_(__other.__has_val_) {
- if (__has_val_) {
- std::construct_at(std::addressof(__union_.__val_), std::move(__other.__union_.__val_));
- } else {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__other.__union_.__unex_));
- }
- }
+ : __union_(__other.__has_val_, std::move(__other.__union_)), __has_val_(__other.__has_val_) { }
private:
template <class _Up, class _OtherErr, class _UfQual, class _OtherErrQual>
@@ -198,36 +183,21 @@ class expected {
expected(const expected<_Up, _OtherErr>& __other)
noexcept(is_nothrow_constructible_v<_Tp, const _Up&> &&
is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
- : __has_val_(__other.__has_val_) {
- if (__has_val_) {
- std::construct_at(std::addressof(__union_.__val_), __other.__union_.__val_);
- } else {
- std::construct_at(std::addressof(__union_.__unex_), __other.__union_.__unex_);
- }
- }
+ : __union_(__other.__has_val_, __other.__union_), __has_val_(__other.__has_val_) {}
template <class _Up, class _OtherErr>
requires __can_convert<_Up, _OtherErr, _Up, _OtherErr>::value
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_Up, _Tp> || !is_convertible_v<_OtherErr, _Err>)
expected(expected<_Up, _OtherErr>&& __other)
noexcept(is_nothrow_constructible_v<_Tp, _Up> && is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
- : __has_val_(__other.__has_val_) {
- if (__has_val_) {
- std::construct_at(std::addressof(__union_.__val_), std::move(__other.__union_.__val_));
- } else {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__other.__union_.__unex_));
- }
- }
+ : __union_(__other.__has_val_, std::move(__other.__union_)), __has_val_(__other.__has_val_) {}
template <class _Up = _Tp>
requires(!is_same_v<remove_cvref_t<_Up>, in_place_t> && !is_same_v<expected, remove_cvref_t<_Up>> &&
!__is_std_unexpected<remove_cvref_t<_Up>>::value && is_constructible_v<_Tp, _Up>)
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_Up, _Tp>)
- expected(_Up&& __u)
- noexcept(is_nothrow_constructible_v<_Tp, _Up>) // strengthened
- : __has_val_(true) {
- std::construct_at(std::addressof(__union_.__val_), std::forward<_Up>(__u));
- }
+ expected(_Up&& __u) noexcept(is_nothrow_constructible_v<_Tp, _Up>) // strengthened
+ : __union_(std::in_place, std::forward<_Up>(__u)), __has_val_(true) {}
template <class _OtherErr>
@@ -235,52 +205,40 @@ class expected {
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
expected(const unexpected<_OtherErr>& __unex)
noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), __unex.error());
- }
+ : __union_(std::unexpect, __unex.error()), __has_val_(false) {}
template <class _OtherErr>
requires is_constructible_v<_Err, _OtherErr>
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
expected(unexpected<_OtherErr>&& __unex)
noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__unex.error()));
- }
+ : __union_(std::unexpect, std::move(__unex.error())), __has_val_(false) {}
template <class... _Args>
requires is_constructible_v<_Tp, _Args...>
_LIBCPP_HIDE_FROM_ABI constexpr explicit expected(in_place_t, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, _Args...>) // strengthened
- : __has_val_(true) {
- std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
- }
+ : __union_(std::in_place, std::forward<_Args>(__args)...), __has_val_(true) {}
template <class _Up, class... _Args>
requires is_constructible_v< _Tp, initializer_list<_Up>&, _Args... >
_LIBCPP_HIDE_FROM_ABI constexpr explicit
expected(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>) // strengthened
- : __has_val_(true) {
- std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
- }
+ : __union_(std::in_place, __il, std::forward<_Args>(__args)...), __has_val_(true) {}
template <class... _Args>
requires is_constructible_v<_Err, _Args...>
_LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, _Args&&... __args)
- noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), std::forward<_Args>(__args)...);
- }
+ noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
+ : __union_(std::unexpect, std::forward<_Args>(__args)...), __has_val_(false) {}
template <class _Up, class... _Args>
requires is_constructible_v< _Err, initializer_list<_Up>&, _Args... >
_LIBCPP_HIDE_FROM_ABI constexpr explicit
expected(unexpect_t, initializer_list<_Up> __il, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), __il, std::forward<_Args>(__args)...);
- }
+ : __union_(std::unexpect, __il, std::forward<_Args>(__args)...), __has_val_(false) {}
// [expected.object.dtor], destructor
@@ -439,9 +397,10 @@ class expected {
std::destroy_at(std::addressof(__union_.__val_));
} else {
std::destroy_at(std::addressof(__union_.__unex_));
- __has_val_ = true;
}
- return *std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
+ std::construct_at(std::addressof(__union_.__val_), std::forward<_Args>(__args)...);
+ __has_val_ = true;
+ return __union_.__val_;
}
template <class _Up, class... _Args>
@@ -451,9 +410,10 @@ class expected {
std::destroy_at(std::addressof(__union_.__val_));
} else {
std::destroy_at(std::addressof(__union_.__unex_));
- __has_val_ = true;
}
- return *std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
+ std::construct_at(std::addressof(__union_.__val_), __il, std::forward<_Args>(__args)...);
+ __has_val_ = true;
+ return __union_.__val_;
}
@@ -892,11 +852,15 @@ class expected {
}
private:
- struct __empty_t {};
-
template <class _ValueType, class _ErrorType>
union __union_t {
- _LIBCPP_HIDE_FROM_ABI constexpr __union_t() {}
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::in_place_t, _Args&&... __args)
+ : __val_(std::forward<_Args>(__args)...) {}
+
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+ : __unex_(std::forward<_Args>(__args)...) {}
template <class _Func, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
@@ -908,6 +872,14 @@ class expected {
std::__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
: __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
+ template <class _Union>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+ if (__has_val)
+ std::construct_at(std::addressof(__val_), std::forward<_Union>(__other).__val_);
+ else
+ std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+ }
+
_LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
requires(is_trivially_destructible_v<_ValueType> && is_trivially_destructible_v<_ErrorType>)
= default;
@@ -926,7 +898,16 @@ class expected {
template <class _ValueType, class _ErrorType>
requires(is_trivially_move_constructible_v<_ValueType> && is_trivially_move_constructible_v<_ErrorType>)
union __union_t<_ValueType, _ErrorType> {
- _LIBCPP_HIDE_FROM_ABI constexpr __union_t() : __empty_() {}
+ _LIBCPP_HIDE_FROM_ABI constexpr __union_t(const __union_t&) = default;
+ _LIBCPP_HIDE_FROM_ABI constexpr __union_t& operator=(const __union_t&) = default;
+
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::in_place_t, _Args&&... __args)
+ : __val_(std::forward<_Args>(__args)...) {}
+
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+ : __unex_(std::forward<_Args>(__args)...) {}
template <class _Func, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
@@ -938,6 +919,14 @@ class expected {
std::__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
: __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
+ template <class _Union>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+ if (__has_val)
+ std::construct_at(std::addressof(__val_), std::forward<_Union>(__other).__val_);
+ else
+ std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+ }
+
_LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
requires(is_trivially_destructible_v<_ValueType> && is_trivially_destructible_v<_ErrorType>)
= default;
@@ -947,7 +936,6 @@ class expected {
requires(!is_trivially_destructible_v<_ValueType> || !is_trivially_destructible_v<_ErrorType>)
{}
- _LIBCPP_NO_UNIQUE_ADDRESS __empty_t __empty_;
_LIBCPP_NO_UNIQUE_ADDRESS _ValueType __val_;
_LIBCPP_NO_UNIQUE_ADDRESS _ErrorType __unex_;
};
@@ -995,11 +983,7 @@ class expected<_Tp, _Err> {
_LIBCPP_HIDE_FROM_ABI constexpr expected(const expected& __rhs)
noexcept(is_nothrow_copy_constructible_v<_Err>) // strengthened
requires(is_copy_constructible_v<_Err> && !is_trivially_copy_constructible_v<_Err>)
- : __has_val_(__rhs.__has_val_) {
- if (!__rhs.__has_val_) {
- std::construct_at(std::addressof(__union_.__unex_), __rhs.__union_.__unex_);
- }
- }
+ : __union_(__rhs.__has_val_, __rhs.__union_), __has_val_(__rhs.__has_val_) {}
_LIBCPP_HIDE_FROM_ABI constexpr expected(expected&&)
requires(is_move_constructible_v<_Err> && is_trivially_move_constructible_v<_Err>)
@@ -1008,51 +992,35 @@ class expected<_Tp, _Err> {
_LIBCPP_HIDE_FROM_ABI constexpr expected(expected&& __rhs)
noexcept(is_nothrow_move_constructible_v<_Err>)
requires(is_move_constructible_v<_Err> && !is_trivially_move_constructible_v<_Err>)
- : __has_val_(__rhs.__has_val_) {
- if (!__rhs.__has_val_) {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__rhs.__union_.__unex_));
- }
- }
+ : __union_(__rhs.__has_val_, std::move(__rhs.__union_)), __has_val_(__rhs.__has_val_) {}
template <class _Up, class _OtherErr>
requires __can_convert<_Up, _OtherErr, const _OtherErr&>::value
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
expected(const expected<_Up, _OtherErr>& __rhs)
noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
- : __has_val_(__rhs.__has_val_) {
- if (!__rhs.__has_val_) {
- std::construct_at(std::addressof(__union_.__unex_), __rhs.__union_.__unex_);
- }
- }
+ : __union_(__rhs.__has_val_, __rhs.__union_), __has_val_(__rhs.__has_val_) {}
template <class _Up, class _OtherErr>
requires __can_convert<_Up, _OtherErr, _OtherErr>::value
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
expected(expected<_Up, _OtherErr>&& __rhs)
noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
- : __has_val_(__rhs.__has_val_) {
- if (!__rhs.__has_val_) {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__rhs.__union_.__unex_));
- }
- }
+ : __union_(__rhs.__has_val_, std::move(__rhs.__union_)), __has_val_(__rhs.__has_val_) {}
template <class _OtherErr>
requires is_constructible_v<_Err, const _OtherErr&>
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<const _OtherErr&, _Err>)
expected(const unexpected<_OtherErr>& __unex)
noexcept(is_nothrow_constructible_v<_Err, const _OtherErr&>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), __unex.error());
- }
+ : __union_(std::unexpect, __unex.error()), __has_val_(false) {}
template <class _OtherErr>
requires is_constructible_v<_Err, _OtherErr>
_LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherErr, _Err>)
expected(unexpected<_OtherErr>&& __unex)
noexcept(is_nothrow_constructible_v<_Err, _OtherErr>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), std::move(__unex.error()));
- }
+ : __union_(std::unexpect, std::move(__unex.error())), __has_val_(false) {}
_LIBCPP_HIDE_FROM_ABI constexpr explicit expected(in_place_t) noexcept : __has_val_(true) {}
@@ -1060,17 +1028,13 @@ class expected<_Tp, _Err> {
requires is_constructible_v<_Err, _Args...>
_LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Err, _Args...>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), std::forward<_Args>(__args)...);
- }
+ : __union_(std::unexpect, std::forward<_Args>(__args)...), __has_val_(false) {}
template <class _Up, class... _Args>
requires is_constructible_v< _Err, initializer_list<_Up>&, _Args... >
_LIBCPP_HIDE_FROM_ABI constexpr explicit expected(unexpect_t, initializer_list<_Up> __il, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Err, initializer_list<_Up>&, _Args...>) // strengthened
- : __has_val_(false) {
- std::construct_at(std::addressof(__union_.__unex_), __il, std::forward<_Args>(__args)...);
- }
+ : __union_(std::unexpect, __il, std::forward<_Args>(__args)...), __has_val_(false) {}
private:
template <class _Func>
@@ -1504,11 +1468,23 @@ class expected<_Tp, _Err> {
union __union_t {
_LIBCPP_HIDE_FROM_ABI constexpr __union_t() : __empty_() {}
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+ : __unex_(std::forward<_Args>(__args)...) {}
+
template <class _Func, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
: __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
+ template <class _Union>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+ if (__has_val)
+ std::construct_at(std::addressof(__empty_));
+ else
+ std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+ }
+
_LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
requires(is_trivially_destructible_v<_ErrorType>)
= default;
@@ -1529,11 +1505,23 @@ class expected<_Tp, _Err> {
union __union_t<_ErrorType> {
_LIBCPP_HIDE_FROM_ABI constexpr __union_t() : __empty_() {}
+ template <class... _Args>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(std::unexpect_t, _Args&&... __args)
+ : __unex_(std::forward<_Args>(__args)...) {}
+
template <class _Func, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(
__expected_construct_unexpected_from_invoke_tag, _Func&& __f, _Args&&... __args)
: __unex_(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
+ template <class _Union>
+ _LIBCPP_HIDE_FROM_ABI constexpr explicit __union_t(bool __has_val, _Union&& __other) {
+ if (__has_val)
+ std::construct_at(std::addressof(__empty_));
+ else
+ std::construct_at(std::addressof(__unex_), std::forward<_Union>(__other).__unex_);
+ }
+
_LIBCPP_HIDE_FROM_ABI constexpr ~__union_t()
requires(is_trivially_destructible_v<_ErrorType>)
= default;
diff --git a/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.intializer_list.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.intializer_list.pass.cpp
index 3cdfcde3f4d6949..922200a8c0263d5 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.intializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.intializer_list.pass.cpp
@@ -81,6 +81,14 @@ constexpr bool test() {
assert(e.value().i == 10);
}
+ // TailClobberer
+ {
+ std::expected<TailClobberer<0>, bool> e(std::unexpect);
+ auto list = {4, 5, 6};
+ e.emplace(list);
+ assert(e.has_value());
+ }
+
return true;
}
diff --git a/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.pass.cpp
index 30392b791c5d41b..520704c7ea6421b 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/assign/emplace.pass.cpp
@@ -76,6 +76,13 @@ constexpr bool test() {
assert(e.value() == 10);
}
+ // TailClobberer
+ {
+ std::expected<TailClobberer<0>, bool> e(std::unexpect);
+ e.emplace();
+ assert(e.has_value());
+ }
+
return true;
}
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.copy.pass.cpp
index 9274b9a2c030e5d..16de28d97039617 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.copy.pass.cpp
@@ -45,6 +45,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
template <class T1, class Err1, class T2, class Err2>
@@ -161,13 +162,19 @@ constexpr bool test() {
assert(e1.error() == 5);
}
+ // convert TailClobberer
+ {
+ const std::expected<TailClobbererNonTrivialMove<0>, char> e1;
+ std::expected<TailClobberer<0>, char> e2 = e1;
+ assert(e2.has_value());
+ assert(e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct ThrowingInt {
ThrowingInt(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.move.pass.cpp
index 71979311bfd1030..0e30ea2c7fe0b45 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.convert.move.pass.cpp
@@ -46,6 +46,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
template <class T1, class Err1, class T2, class Err2>
@@ -160,13 +161,19 @@ constexpr bool test() {
assert(e1.error().get() == 0);
}
+ // convert TailClobberer
+ {
+ std::expected<TailClobbererNonTrivialMove<0>, char> e1;
+ std::expected<TailClobberer<0>, char> e2 = std::move(e1);
+ assert(e2.has_value());
+ assert(e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct ThrowingInt {
ThrowingInt(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.copy.pass.cpp
index 77d73485025ab64..581df51207da29f 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.copy.pass.cpp
@@ -30,6 +30,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
struct NonCopyable {
NonCopyable(const NonCopyable&) = delete;
@@ -93,13 +94,26 @@ constexpr bool test() {
assert(!e2.has_value());
assert(e2.error() == 5);
}
+
+ // copy TailClobberer as value
+ {
+ const std::expected<TailClobberer<0>, bool> e1;
+ auto e2 = e1;
+ assert(e2.has_value());
+ }
+
+ // copy TailClobberer as error
+ {
+ const std::expected<bool, TailClobberer<1>> e1(std::unexpect);
+ auto e2 = e1;
+ assert(!e2.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing() = default;
Throwing(const Throwing&) { throw Except{}; }
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.default.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.default.pass.cpp
index 431e604e8b692f7..dcd046bdd9d8936 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.default.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.default.pass.cpp
@@ -22,6 +22,7 @@
#include <type_traits>
#include "test_macros.h"
+#include "../../types.h"
struct NoDedefaultCtor {
NoDedefaultCtor() = delete;
@@ -45,6 +46,7 @@ constexpr void testDefaultCtor() {
template <class T>
constexpr void testTypes() {
+ testDefaultCtor<T, bool>();
testDefaultCtor<T, int>();
testDefaultCtor<T, NoDedefaultCtor>();
}
@@ -52,13 +54,12 @@ constexpr void testTypes() {
constexpr bool test() {
testTypes<int>();
testTypes<MyInt>();
+ testTypes<TailClobberer<0>>();
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing() { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp
index 92952551711e043..88ec41939439afa 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace.pass.cpp
@@ -26,6 +26,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(std::is_constructible_v<std::expected<int, int>, std::in_place_t>);
@@ -54,24 +55,24 @@ struct CopyOnly {
friend constexpr bool operator==(const CopyOnly& mi, int ii) { return mi.i == ii; }
};
-template <class T>
+template <class T, class E = int>
constexpr void testInt() {
- std::expected<T, int> e(std::in_place, 5);
+ std::expected<T, E> e(std::in_place, 5);
assert(e.has_value());
assert(e.value() == 5);
}
-template <class T>
+template <class T, class E = int>
constexpr void testLValue() {
T t(5);
- std::expected<T, int> e(std::in_place, t);
+ std::expected<T, E> e(std::in_place, t);
assert(e.has_value());
assert(e.value() == 5);
}
-template <class T>
+template <class T, class E = int>
constexpr void testRValue() {
- std::expected<T, int> e(std::in_place, T(5));
+ std::expected<T, E> e(std::in_place, T(5));
assert(e.has_value());
assert(e.value() == 5);
}
@@ -80,10 +81,13 @@ constexpr bool test() {
testInt<int>();
testInt<CopyOnly>();
testInt<MoveOnly>();
+ testInt<TailClobberer<0>, bool>();
testLValue<int>();
testLValue<CopyOnly>();
+ testLValue<TailClobberer<0>, bool>();
testRValue<int>();
testRValue<MoveOnly>();
+ testRValue<TailClobberer<0>, bool>();
// no arg
{
@@ -111,8 +115,6 @@ constexpr bool test() {
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace_init_list.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace_init_list.pass.cpp
index 3d62967fa77ee2f..5f206b867a965e5 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace_init_list.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.inplace_init_list.pass.cpp
@@ -31,6 +31,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(
@@ -93,13 +94,17 @@ constexpr bool test() {
assert(m.get() == 0);
}
+ // TailClobberer
+ {
+ std::expected<TailClobberer<0>, bool> e(std::in_place, {1, 2, 3});
+ assert(e.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(std::initializer_list<int>, int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.move.pass.cpp
index 5e6749e50c16c97..cd89e2445860a2a 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.move.pass.cpp
@@ -32,6 +32,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
struct NonMovable {
NonMovable(NonMovable&&) = delete;
@@ -112,13 +113,28 @@ constexpr bool test() {
assert(e2.error() == 5);
assert(!e1.has_value());
}
+
+ // move TailClobbererNonTrivialMove as value
+ {
+ std::expected<TailClobbererNonTrivialMove<0>, bool> e1;
+ auto e2 = std::move(e1);
+ assert(e2.has_value());
+ assert(e1.has_value());
+ }
+
+ // move TailClobbererNonTrivialMove as error
+ {
+ std::expected<bool, TailClobbererNonTrivialMove<1>> e1(std::unexpect);
+ auto e2 = std::move(e1);
+ assert(!e2.has_value());
+ assert(!e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing() = default;
Throwing(Throwing&&) { throw Except{}; }
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.u.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.u.pass.cpp
index f05c2d15f3bbe50..8ec6022850d249f 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.u.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.u.pass.cpp
@@ -29,6 +29,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(std::is_constructible_v<std::expected<int, int>, int>);
@@ -67,24 +68,27 @@ struct CopyOnly {
friend constexpr bool operator==(const CopyOnly& mi, int ii) { return mi.i == ii; }
};
-template <class T>
+struct BaseError {};
+struct DerivedError : BaseError {};
+
+template <class T, class E = int>
constexpr void testInt() {
- std::expected<T, int> e(5);
+ std::expected<T, E> e(5);
assert(e.has_value());
assert(e.value() == 5);
}
-template <class T>
+template <class T, class E = int>
constexpr void testLValue() {
T t(5);
- std::expected<T, int> e(t);
+ std::expected<T, E> e(t);
assert(e.has_value());
assert(e.value() == 5);
}
-template <class T>
+template <class T, class E = int>
constexpr void testRValue() {
- std::expected<T, int> e(T(5));
+ std::expected<T, E> e(T(5));
assert(e.has_value());
assert(e.value() == 5);
}
@@ -93,10 +97,13 @@ constexpr bool test() {
testInt<int>();
testInt<CopyOnly>();
testInt<MoveOnly>();
+ testInt<TailClobberer<0>, bool>();
testLValue<int>();
testLValue<CopyOnly>();
+ testLValue<TailClobberer<0>, bool>();
testRValue<int>();
testRValue<MoveOnly>();
+ testRValue<TailClobberer<0>, bool>();
// Test default template argument.
// Without it, the template parameter cannot be deduced from an initializer list
@@ -129,8 +136,6 @@ constexpr bool test() {
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect.pass.cpp
index 5a78e41dfcae259..27ce97737d288ba 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect.pass.cpp
@@ -26,6 +26,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(std::is_constructible_v<std::expected<int, int>, std::unexpect_t>);
@@ -54,24 +55,24 @@ struct CopyOnly {
friend constexpr bool operator==(const CopyOnly& mi, int ii) { return mi.i == ii; }
};
-template <class T>
+template <class T, class V = int>
constexpr void testInt() {
- std::expected<int, T> e(std::unexpect, 5);
+ std::expected<V, T> e(std::unexpect, 5);
assert(!e.has_value());
assert(e.error() == 5);
}
-template <class T>
+template <class T, class V = int>
constexpr void testLValue() {
T t(5);
- std::expected<int, T> e(std::unexpect, t);
+ std::expected<V, T> e(std::unexpect, t);
assert(!e.has_value());
assert(e.error() == 5);
}
-template <class T>
+template <class T, class V = int>
constexpr void testRValue() {
- std::expected<int, T> e(std::unexpect, T(5));
+ std::expected<V, T> e(std::unexpect, T(5));
assert(!e.has_value());
assert(e.error() == 5);
}
@@ -80,10 +81,13 @@ constexpr bool test() {
testInt<int>();
testInt<CopyOnly>();
testInt<MoveOnly>();
+ testInt<TailClobberer<1>, bool>();
testLValue<int>();
testLValue<CopyOnly>();
+ testLValue<TailClobberer<1>, bool>();
testRValue<int>();
testRValue<MoveOnly>();
+ testRValue<TailClobberer<1>, bool>();
// no arg
{
@@ -111,8 +115,6 @@ constexpr bool test() {
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect_init_list.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect_init_list.pass.cpp
index 09bfb535606fd5c..9771aa77792ada2 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect_init_list.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpect_init_list.pass.cpp
@@ -31,6 +31,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(
@@ -93,13 +94,17 @@ constexpr bool test() {
assert(m.get() == 0);
}
+ // TailClobberer
+ {
+ std::expected<bool, TailClobberer<1>> e(std::unexpect, {1, 2, 3});
+ assert(!e.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(std::initializer_list<int>, int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.copy.pass.cpp
index 09ac91182b3b892..bbfd3048533c793 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.copy.pass.cpp
@@ -27,6 +27,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints
static_assert(std::is_constructible_v<std::expected<int, int>, const std::unexpected<int>&>);
@@ -49,10 +50,10 @@ struct MyInt {
friend constexpr bool operator==(const MyInt&, const MyInt&) = default;
};
-template <class T>
+template <class T, class V = int>
constexpr void testUnexpected() {
const std::unexpected<int> u(5);
- std::expected<int, T> e(u);
+ std::expected<V, T> e(u);
assert(!e.has_value());
assert(e.error() == 5);
}
@@ -60,13 +61,12 @@ constexpr void testUnexpected() {
constexpr bool test() {
testUnexpected<int>();
testUnexpected<MyInt>();
+ testUnexpected<TailClobberer<1>, bool>();
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.move.pass.cpp
index 9aaaa3fe1a448dd..800d47bda69587b 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/ctor/ctor.unexpected.move.pass.cpp
@@ -27,6 +27,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints
static_assert(std::is_constructible_v<std::expected<int, int>, std::unexpected<int>>);
@@ -49,10 +50,10 @@ struct MyInt {
friend constexpr bool operator==(const MyInt&, const MyInt&) = default;
};
-template <class Err>
+template <class Err, class V = int>
constexpr void testInt() {
std::unexpected<int> u(5);
- std::expected<int, Err> e(std::move(u));
+ std::expected<V, Err> e(std::move(u));
assert(!e.has_value());
assert(e.error() == 5);
}
@@ -69,14 +70,13 @@ constexpr bool test() {
testInt<int>();
testInt<MyInt>();
testInt<MoveOnly>();
+ testInt<TailClobberer<1>, bool>();
testMoveOnly();
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.expected/observers/has_value.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/observers/has_value.pass.cpp
index 27d657a065699ea..2b24b0ac24ddb8f 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/observers/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/observers/has_value.pass.cpp
@@ -12,10 +12,12 @@
#include <cassert>
#include <concepts>
#include <expected>
+#include <optional>
#include <type_traits>
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
// Test noexcept
template <class T>
@@ -43,6 +45,36 @@ constexpr bool test() {
assert(!e.has_value());
}
+ // The following tests check that the "has_value" flag is not overwritten
+ // by the constructor of the value. This could happen because the flag is
+ // stored in the tail padding of the value.
+ //
+ // The first test is a simplified version of the real code where this was
+ // first observed.
+ //
+ // The other tests use a synthetic struct that clobbers its tail padding
+ // on construction, making the issue easier to reproduce.
+ //
+ // See https://github.com/llvm/llvm-project/issues/68552 and the linked PR.
+ {
+ auto f1 = [] -> std::expected<std::optional<int>, long> { return 0; };
+
+ auto f2 = [&f1] -> std::expected<std::optional<int>, int> {
+ return f1().transform_error([](auto) { return 0; });
+ };
+
+ auto e = f2();
+ assert(e.has_value());
+ }
+ {
+ const std::expected<TailClobberer<0>, bool> e = {};
+ // clang-cl does not support [[no_unique_address]] yet.
+#if !(defined(TEST_COMPILER_CLANG) && defined(_MSC_VER))
+ LIBCPP_STATIC_ASSERT(sizeof(TailClobberer<0>) == sizeof(e));
+#endif
+ assert(e.has_value());
+ }
+
return true;
}
diff --git a/libcxx/test/std/utilities/expected/expected.expected/swap/free.swap.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/swap/free.swap.pass.cpp
index 2a004b0cd747496..4a94ee0ee597fe8 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/swap/free.swap.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/swap/free.swap.pass.cpp
@@ -131,7 +131,7 @@ constexpr bool test() {
std::expected<TrackedMove<true>, TrackedMove<false>> e1(std::in_place, 5);
std::expected<TrackedMove<true>, TrackedMove<false>> e2(std::unexpect, 10);
- e1.swap(e2);
+ swap(e1, e2);
assert(!e1.has_value());
assert(e1.error().i == 10);
@@ -182,6 +182,35 @@ constexpr bool test() {
assert(!e2.error().swapCalled);
}
+ // TailClobberer
+ {
+ // is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, true>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, true>> y(std::unexpect);
+
+ swap(x, y);
+
+ // Both of these would fail if adjusting the "has value" flags happened
+ // _before_ constructing the member objects inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+
+ // !is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, false>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, false>> y(std::unexpect);
+
+ swap(x, y);
+
+ // Both of these would fail if adjusting the "has value" flags happened
+ // _before_ constructing the member objects inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+ }
+
return true;
}
@@ -212,6 +241,39 @@ void testException() {
assert(*e1 == 5);
}
}
+
+ // TailClobberer
+ {
+ // is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, false, true>, TailClobbererNonTrivialMove<1>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, false, true>, TailClobbererNonTrivialMove<1>> y(std::unexpect);
+ try {
+ swap(x, y);
+ assert(false);
+ } catch (Except) {
+ assert(x.has_value());
+ // This would fail if `TailClobbererNonTrivialMove<1>` clobbered the
+ // flag when rolling back the swap.
+ assert(!y.has_value());
+ }
+ }
+
+ // !is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0>, TailClobbererNonTrivialMove<1, false, true>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0>, TailClobbererNonTrivialMove<1, false, true>> y(std::unexpect);
+ try {
+ swap(x, y);
+ assert(false);
+ } catch (Except) {
+ // This would fail if `TailClobbererNonTrivialMove<0>` clobbered the
+ // flag when rolling back the swap.
+ assert(x.has_value());
+ assert(!y.has_value());
+ }
+ }
+ }
#endif // TEST_HAS_NO_EXCEPTIONS
}
diff --git a/libcxx/test/std/utilities/expected/expected.expected/swap/member.swap.pass.cpp b/libcxx/test/std/utilities/expected/expected.expected/swap/member.swap.pass.cpp
index d2d4a0992209271..b6b112cfbeb8ba7 100644
--- a/libcxx/test/std/utilities/expected/expected.expected/swap/member.swap.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.expected/swap/member.swap.pass.cpp
@@ -70,7 +70,7 @@ static_assert(!HasMemberSwap<MoveMayThrow, MoveMayThrow>);
// Test noexcept
template <class T, class E>
-concept MemberSwapNoexcept =
+concept MemberSwapNoexcept = //
requires(std::expected<T, E> x, std::expected<T, E> y) {
{ x.swap(y) } noexcept;
};
@@ -198,6 +198,35 @@ constexpr bool test() {
assert(!e2.error().swapCalled);
}
+ // TailClobberer
+ {
+ // is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, true>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, true>> y(std::unexpect);
+
+ x.swap(y);
+
+ // Both of these would fail if adjusting the "has value" flags happened
+ // _before_ constructing the member objects inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+
+ // !is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, false>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, true>, TailClobbererNonTrivialMove<1, false>> y(std::unexpect);
+
+ x.swap(y);
+
+ // Both of these would fail if adjusting the "has value" flags happened
+ // _before_ constructing the member objects inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+ }
+
return true;
}
@@ -228,6 +257,39 @@ void testException() {
assert(*e1 == 5);
}
}
+
+ // TailClobberer
+ {
+ // is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0, false, true>, TailClobbererNonTrivialMove<1>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0, false, true>, TailClobbererNonTrivialMove<1>> y(std::unexpect);
+ try {
+ x.swap(y);
+ assert(false);
+ } catch (Except) {
+ assert(x.has_value());
+ // This would fail if `TailClobbererNonTrivialMove<1>` clobbered the
+ // flag when rolling back the swap.
+ assert(!y.has_value());
+ }
+ }
+
+ // !is_nothrow_move_constructible_v<E>
+ {
+ std::expected<TailClobbererNonTrivialMove<0>, TailClobbererNonTrivialMove<1, false, true>> x(std::in_place);
+ std::expected<TailClobbererNonTrivialMove<0>, TailClobbererNonTrivialMove<1, false, true>> y(std::unexpect);
+ try {
+ x.swap(y);
+ assert(false);
+ } catch (Except) {
+ // This would fail if `TailClobbererNonTrivialMove<0>` clobbered the
+ // flag when rolling back the swap.
+ assert(x.has_value());
+ assert(!y.has_value());
+ }
+ }
+ }
#endif // TEST_HAS_NO_EXCEPTIONS
}
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.copy.pass.cpp
index 40f8efa5f94bf9d..05f556e25eac14c 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.copy.pass.cpp
@@ -33,6 +33,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
template <class T1, class Err1, class T2, class Err2>
@@ -97,13 +98,19 @@ constexpr bool test() {
assert(e1.error() == 5);
}
+ // convert TailClobberer
+ {
+ const std::expected<void, TailClobbererNonTrivialMove<1>> e1(std::unexpect);
+ std::expected<void, TailClobberer<1>> e2 = e1;
+ assert(!e2.has_value());
+ assert(!e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct ThrowingInt {
ThrowingInt(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.move.pass.cpp
index b28fc7a03bb3445..a48888be53ee07a 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.convert.move.pass.cpp
@@ -34,6 +34,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
template <class T1, class Err1, class T2, class Err2>
@@ -98,13 +99,19 @@ constexpr bool test() {
assert(e1.error().get() == 0);
}
+ // convert TailClobberer
+ {
+ std::expected<void, TailClobbererNonTrivialMove<1>> e1(std::unexpect);
+ std::expected<void, TailClobberer<1>> e2 = std::move(e1);
+ assert(!e2.has_value());
+ assert(!e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct ThrowingInt {
ThrowingInt(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.copy.pass.cpp
index 689f152a3ac5547..7c04a5fa9d04404 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.copy.pass.cpp
@@ -25,6 +25,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
struct NonCopyable {
NonCopyable(const NonCopyable&) = delete;
@@ -62,13 +63,19 @@ constexpr bool test() {
assert(!e2.has_value());
assert(e2.error() == 5);
}
+
+ // copy TailClobberer as error
+ {
+ const std::expected<void, TailClobberer<1>> e1(std::unexpect);
+ auto e2 = e1;
+ assert(!e2.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing() = default;
Throwing(const Throwing&) { throw Except{}; }
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.move.pass.cpp
index 61bce2be4897f0a..bfb5028c9264d02 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.move.pass.cpp
@@ -25,6 +25,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
struct NonMovable {
NonMovable(NonMovable&&) = delete;
@@ -76,13 +77,20 @@ constexpr bool test() {
assert(e2.error() == 5);
assert(!e1.has_value());
}
+
+ // move TailClobbererNonTrivialMove as error
+ {
+ std::expected<void, TailClobbererNonTrivialMove<1>> e1(std::unexpect);
+ auto e2 = std::move(e1);
+ assert(!e2.has_value());
+ assert(!e1.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing() = default;
Throwing(Throwing&&) { throw Except{}; }
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect.pass.cpp
index 0a857c77d9c7a68..85bc98d7f462de1 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect.pass.cpp
@@ -26,6 +26,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(std::is_constructible_v<std::expected<void, int>, std::unexpect_t>);
@@ -80,10 +81,13 @@ constexpr bool test() {
testInt<int>();
testInt<CopyOnly>();
testInt<MoveOnly>();
+ testInt<TailClobberer<1>>();
testLValue<int>();
testLValue<CopyOnly>();
+ testLValue<TailClobberer<1>>();
testRValue<int>();
testRValue<MoveOnly>();
+ testRValue<TailClobberer<1>>();
// no arg
{
@@ -111,8 +115,6 @@ constexpr bool test() {
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect_init_list.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect_init_list.pass.cpp
index f116432962e09e3..8e4a8eaf87484a6 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect_init_list.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpect_init_list.pass.cpp
@@ -30,6 +30,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints:
static_assert(
@@ -91,13 +92,17 @@ constexpr bool test() {
assert(m.get() == 0);
}
+ // TailClobberer
+ {
+ std::expected<void, TailClobberer<1>> e(std::unexpect, {1, 2, 3});
+ assert(!e.has_value());
+ }
+
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(std::initializer_list<int>, int) { throw Except{}; };
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.copy.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.copy.pass.cpp
index 89e1c9275e3e062..ba738a3e339de78 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.copy.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.copy.pass.cpp
@@ -27,6 +27,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints
static_assert(std::is_constructible_v<std::expected<void, int>, const std::unexpected<int>&>);
@@ -60,13 +61,12 @@ constexpr void testUnexpected() {
constexpr bool test() {
testUnexpected<int>();
testUnexpected<MyInt>();
+ testUnexpected<TailClobberer<1>>();
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.move.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.move.pass.cpp
index 2ddcb63c085f052..33a5e7293df2143 100644
--- a/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.move.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/ctor/ctor.unexpected.move.pass.cpp
@@ -27,6 +27,7 @@
#include "MoveOnly.h"
#include "test_macros.h"
+#include "../../types.h"
// Test Constraints
static_assert(std::is_constructible_v<std::expected<void, int>, std::unexpected<int>>);
@@ -69,14 +70,13 @@ constexpr bool test() {
testInt<int>();
testInt<MyInt>();
testInt<MoveOnly>();
+ testInt<TailClobberer<1>>();
testMoveOnly();
return true;
}
void testException() {
#ifndef TEST_HAS_NO_EXCEPTIONS
- struct Except {};
-
struct Throwing {
Throwing(int) { throw Except{}; }
};
diff --git a/libcxx/test/std/utilities/expected/expected.void/observers/has_value.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/observers/has_value.pass.cpp
index 42a173d60c898c6..fe92bb401643d8b 100644
--- a/libcxx/test/std/utilities/expected/expected.void/observers/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/observers/has_value.pass.cpp
@@ -16,6 +16,7 @@
#include <utility>
#include "test_macros.h"
+#include "../../types.h"
// Test noexcept
template <class T>
@@ -43,6 +44,17 @@ constexpr bool test() {
assert(!e.has_value());
}
+ // See comments of the corresponding test in
+ // "expected.expected/observers/has_value.pass.cpp".
+ {
+ const std::expected<void, TailClobberer<1>> e(std::unexpect);
+ // clang-cl does not support [[no_unique_address]] yet.
+#if !(defined(TEST_COMPILER_CLANG) && defined(_MSC_VER))
+ LIBCPP_STATIC_ASSERT(sizeof(TailClobberer<1>) == sizeof(e));
+#endif
+ assert(!e.has_value());
+ }
+
return true;
}
diff --git a/libcxx/test/std/utilities/expected/expected.void/swap/free.swap.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/swap/free.swap.pass.cpp
index b293fe27c8d80bb..9587b891b1a4ac0 100644
--- a/libcxx/test/std/utilities/expected/expected.void/swap/free.swap.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/swap/free.swap.pass.cpp
@@ -93,7 +93,7 @@ constexpr bool test() {
std::expected<void, Traced> e1(std::in_place);
std::expected<void, Traced> e2(std::unexpect, s, 10);
- e1.swap(e2);
+ swap(e1, e2);
assert(!e1.has_value());
assert(e1.error().data_ == 10);
@@ -109,7 +109,7 @@ constexpr bool test() {
std::expected<void, Traced> e1(std::unexpect, s, 10);
std::expected<void, Traced> e2(std::in_place);
- e1.swap(e2);
+ swap(e1, e2);
assert(e1.has_value());
assert(!e2.has_value());
@@ -119,6 +119,19 @@ constexpr bool test() {
assert(s.dtorCalled);
}
+ // TailClobberer
+ {
+ std::expected<void, TailClobbererNonTrivialMove<1>> x(std::in_place);
+ std::expected<void, TailClobbererNonTrivialMove<1>> y(std::unexpect);
+
+ swap(x, y);
+
+ // The next line would fail if adjusting the "has value" flag happened
+ // _before_ constructing the member object inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+
return true;
}
@@ -153,6 +166,21 @@ void testException() {
assert(!e2Destroyed);
}
}
+
+ // TailClobberer
+ {
+ std::expected<void, TailClobbererNonTrivialMove<0, false, true>> x(std::in_place);
+ std::expected<void, TailClobbererNonTrivialMove<0, false, true>> y(std::unexpect);
+ try {
+ swap(x, y);
+ assert(false);
+ } catch (Except) {
+ // This would fail if `TailClobbererNonTrivialMove<0, false, true>`
+ // clobbered the flag before throwing the exception.
+ assert(x.has_value());
+ assert(!y.has_value());
+ }
+ }
#endif // TEST_HAS_NO_EXCEPTIONS
}
diff --git a/libcxx/test/std/utilities/expected/expected.void/swap/member.swap.pass.cpp b/libcxx/test/std/utilities/expected/expected.void/swap/member.swap.pass.cpp
index 3eed916d431eef7..82554dae04355ca 100644
--- a/libcxx/test/std/utilities/expected/expected.void/swap/member.swap.pass.cpp
+++ b/libcxx/test/std/utilities/expected/expected.void/swap/member.swap.pass.cpp
@@ -54,7 +54,7 @@ struct MoveMayThrow {
};
template <class E>
-concept MemberSwapNoexcept =
+concept MemberSwapNoexcept = //
requires(std::expected<void, E> x, std::expected<void, E> y) {
{ x.swap(y) } noexcept;
};
@@ -128,6 +128,19 @@ constexpr bool test() {
assert(s.dtorCalled);
}
+ // TailClobberer
+ {
+ std::expected<void, TailClobbererNonTrivialMove<1>> x(std::in_place);
+ std::expected<void, TailClobbererNonTrivialMove<1>> y(std::unexpect);
+
+ x.swap(y);
+
+ // The next line would fail if adjusting the "has value" flag happened
+ // _before_ constructing the member object inside the `swap`.
+ assert(!x.has_value());
+ assert(y.has_value());
+ }
+
return true;
}
@@ -162,6 +175,21 @@ void testException() {
assert(!e2Destroyed);
}
}
+
+ // TailClobberer
+ {
+ std::expected<void, TailClobbererNonTrivialMove<0, false, true>> x(std::in_place);
+ std::expected<void, TailClobbererNonTrivialMove<0, false, true>> y(std::unexpect);
+ try {
+ x.swap(y);
+ assert(false);
+ } catch (Except) {
+ // This would fail if `TailClobbererNonTrivialMove<0, false, true>`
+ // clobbered the flag before throwing the exception.
+ assert(x.has_value());
+ assert(!y.has_value());
+ }
+ }
#endif // TEST_HAS_NO_EXCEPTIONS
}
diff --git a/libcxx/test/std/utilities/expected/types.h b/libcxx/test/std/utilities/expected/types.h
index 278ab0f0ec7468f..ecab3ce454c98ca 100644
--- a/libcxx/test/std/utilities/expected/types.h
+++ b/libcxx/test/std/utilities/expected/types.h
@@ -9,7 +9,9 @@
#ifndef TEST_STD_UTILITIES_EXPECTED_TYPES_H
#define TEST_STD_UTILITIES_EXPECTED_TYPES_H
+#include <cstring>
#include <utility>
+#include <type_traits>
#include "test_macros.h"
template <bool copyMoveNoexcept, bool convertNoexcept = true>
@@ -142,4 +144,51 @@ struct ThrowOnMove {
#endif // TEST_HAS_NO_EXCEPTIONS
+// This type has one byte of tail padding where `std::expected` may put its
+// "has value" flag. The constructor will clobber all bytes including the
+// tail padding. With this type we can check that `std::expected` handles
+// the case where the "has value" flag is an overlapping subobject correctly.
+//
+// See https://github.com/llvm/llvm-project/issues/68552 for details.
+template <int Constant>
+struct TailClobberer {
+ constexpr TailClobberer() noexcept {
+ if (!std::is_constant_evaluated()) {
+ std::memset(this, Constant, sizeof(*this));
+ }
+ // Always set `b` itself to `false` so that the comparison works.
+ b = false;
+ }
+ constexpr TailClobberer(const TailClobberer&) : TailClobberer() {}
+ constexpr TailClobberer(TailClobberer&&) = default;
+ // Converts from `int`/`std::initializer_list<int>, used in some tests.
+ constexpr TailClobberer(int) : TailClobberer() {}
+ constexpr TailClobberer(std::initializer_list<int>) noexcept : TailClobberer() {}
+
+ friend constexpr bool operator==(const TailClobberer&, const TailClobberer&) = default;
+
+ friend constexpr void swap(TailClobberer&, TailClobberer&){};
+
+private:
+ alignas(2) bool b;
+};
+static_assert(!std::is_trivially_copy_constructible_v<TailClobberer<0>>);
+static_assert(std::is_trivially_move_constructible_v<TailClobberer<0>>);
+
+template <int Constant, bool Noexcept = true, bool ThrowOnMove = false>
+struct TailClobbererNonTrivialMove : TailClobberer<Constant> {
+ using TailClobberer<Constant>::TailClobberer;
+ constexpr TailClobbererNonTrivialMove(TailClobbererNonTrivialMove&&) noexcept(Noexcept) : TailClobberer<Constant>() {
+#ifndef TEST_HAS_NO_EXCEPTIONS
+ if constexpr (!Noexcept && ThrowOnMove)
+ throw Except{};
+#endif
+ }
+};
+static_assert(!std::is_trivially_copy_constructible_v<TailClobbererNonTrivialMove<0>>);
+static_assert(std::is_move_constructible_v<TailClobbererNonTrivialMove<0>>);
+static_assert(!std::is_trivially_move_constructible_v<TailClobbererNonTrivialMove<0>>);
+static_assert(std::is_nothrow_move_constructible_v<TailClobbererNonTrivialMove<0, true>>);
+static_assert(!std::is_nothrow_move_constructible_v<TailClobbererNonTrivialMove<0, false>>);
+
#endif // TEST_STD_UTILITIES_EXPECTED_TYPES_H
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