It's possible for the function pointer comparison to fail even though
the type is correct, because the function could be defined multiple
times with different addresses when shared libraries are in use.
Retain the function pointer check for the common case where the check
succeeds, but compare typeinfo (if RTTI is enabled) if the first check
fails.
* include/experimental/any (__any_caster): Use RTTI if comparing
addresses fails, to support non-unique addresses in shared libraries.
* include/std/any (__any_caster): Likewise.
From-SVN: r271557
Although the std::any constructors use decay_t to determine the type of
the contained value, std::any_cast should use the un-decayed type (and
so always fail for function and array types that decay to pointers).
Using remove_cv_t is correct, because the condition for std::any_cast
to return non-null is operand.type() == typeid(T) and typeid ignores
top-level cv-qualifiers.
PR libstdc++/90220
* include/std/any (__any_caster): Use remove_cv_t instead of decay_t.
Avoid a runtime check for types that can never be stored in std::any.
* testsuite/20_util/any/misc/any_cast.cc: Test std::any_cast with
array types.
From-SVN: r270547
PR libstdc++/90220 (partial)
* include/std/any (any_cast<T>(any*), any_cast<T>(const any*)): Do
not attempt ill-formed static_cast to pointers to non-object types.
* testsuite/20_util/any/misc/any_cast.cc: Test std::any_cast with
function types.
From-SVN: r270538
Avoid creating arbitrarily large objects on the stack when emplacing
trivially copyable objects into a variant. Currently we provide the
strong exception-safety guarantee for all trivially copyable types, by
constructing a second variant and then doing a non-throwing move
assignment from the temporary. This patch restricts that behaviour to
trivially copyable types that are no larger than 256 bytes. For larger
types the object will be emplaced directly into the variant, and if its
initialization throws then the variant becomes valueless.
Also implement Antony Polukhin's suggestion to whitelist specific types
that are not trivially copyable but can be efficiently move-assigned.
Emplacing those types will never cause a variant to become valueless.
The whitelisted types are: std::shared_ptr, std::weak_ptr,
std::unique_ptr, std::function, and std::any. Additionally,
std::basic_string, std::vector, and __gnu_debug::vector are whitelisted
if their allocator traits give them a non-throwing move assignment
operator. Specifically, this means std::string is whitelisted, but
std::pmr::string is not.
As part of this patch, additional if-constexpr branches are added for
the cases where the initialization is known to be non-throwing (so the
overhead of the try-catch block can be avoided) and where a scalar is
being produced by a potentially-throwing conversion operator (so that
the overhead of constructing and move-assigning a variant is avoided).
These changes should have no semantic effect, just better codegen.
PR libstdc++/87431 (again)
* include/bits/basic_string.h (__variant::_Never_valueless_alt):
Define partial specialization for basic_string.
* include/bits/shared_ptr.h (_Never_valueless_alt): Likewise for
shared_ptr and weak_ptr.
* include/bits/std_function.h (_Never_valueless_alt): Likewise for
function.
* include/bits/stl_vector.h (_Never_valueless_alt): Likewise for
vector.
* include/bits/unique_ptr.h (_Never_valueless_alt): Likewise for
unique_ptr.
* include/debug/vector (_Never_valueless_alt): Likewise for debug
vector.
* include/std/any (_Never_valueless_alt): Define explicit
specialization for any.
* include/std/variant (_Never_valueless_alt): Define primary template.
(__never_valueless): Use _Never_valueless_alt instead of
is_trivially_copyable.
(variant::emplace<N>(Args&&...)): Add special case for non-throwing
initializations to avoid try-catch overhead. Add special case for
scalars produced by potentially-throwing conversions. Use
_Never_valueless_alt instead of is_trivially_copyable for the
remaining strong exception-safety cases.
(variant::emplace<N>(initializer_list<U>, Args&&...)): Likewise.
* testsuite/20_util/variant/87431.cc: Run both test functions.
* testsuite/20_util/variant/exception_safety.cc: New test.
* testsuite/20_util/variant/run.cc: Use pmr::string instead of string,
so the variant becomes valueless.
From-SVN: r270170
PR libstdc++/83658
* include/std/any (any::__do_emplace): Only set _M_manager after
constructing the contained object.
* testsuite/20_util/any/misc/any_cast_neg.cc: Adjust dg-error line.
* testsuite/20_util/any/modifiers/83658.cc: New test.
From-SVN: r257141
PR libstdc++/79433
* doc/xml/manual/status_cxx2017.xml: Update feature-test macros.
* doc/html/*: Regenerate.
* include/Makefile.am: Remove <bits/c++17_warning.h>.
* include/Makefile.in: Regenerate.
* include/bits/c++17_warning.h: Remove.
* include/bits/string_view.tcc: Do not include <bits/c++17_warning.h>
for pre-C++17 modes.
* include/std/any: Likewise.
(__cpp_lib_any): Define.
* include/std/mutex (__cpp_lib_scoped_lock): Adjust value as per new
SD-6 draft.
* include/std/numeric (__cpp_lib_gcd_lcm): Define as per new SD-6
draft.
* include/std/optional: Do not include <bits/c++17_warning.h>.
(__cpp_lib_optional): Define.
* include/std/shared_mutex: Do not include <bits/c++14_warning.h>.
* include/std/string_view: Do not include <bits/c++17_warning.h>.
(__cpp_lib_string_view): Define.
* include/std/variant: Do not include <bits/c++17_warning.h>.
(__cpp_lib_variant): Define.
* testsuite/20_util/optional/cons/value_neg.cc: Adjust dg-error line
numbers.
* testsuite/26_numerics/gcd/1.cc: Test for __cpp_lib_gcd_lcm.
* testsuite/26_numerics/gcd/gcd_neg.cc: Adjust dg-error line
numbers.
* testsuite/26_numerics/lcm/1.cc: Test for __cpp_lib_gcd_lcm.
* testsuite/26_numerics/lcm/lcm_neg.cc: Adjust dg-error line
numbers.
* testsuite/30_threads/scoped_lock/requirements/typedefs.cc: Adjust
expected value of __cpp_lib_scoped_lock.
From-SVN: r252018
Implement LWG 2857, {variant,optional,any}::emplace should
return the constructed value.
* include/std/any (emplace(_Args&&...)): Change the return type and
return a reference to the constructed value.
(emplace(initializer_list<_Up>, _Args&&...)): Likewise.
* include/std/optional (emplace(_Args&&...)): Likewise.
(emplace(initializer_list<_Up>, _Args&&...)): Likewise.
* include/std/variant (emplace<_Tp>(_Args&&...)): Likewise.
(emplace<_Tp>(initializer_list<_Up>, _Args&&...)): Likewise.
(emplace<_Np>(_Args&&...)): Likewise.
(emplace<_Np>(initializer_list<_Up>, _Args&&...)): Likewise.
* testsuite/20_util/any/assign/emplace.cc: Add tests for
checking the return value of emplace.
* testsuite/20_util/any/misc/any_cast_neg.cc: Adjust.
* testsuite/20_util/optional/assignment/6.cc: Add tests for
checking the return value of emplace.
* testsuite/20_util/variant/run.cc: Likewise.
From-SVN: r246182
Implement LWG 2769, Redundant const in the return type of
any_cast(const any&).
* include/std/any (_AnyCast): New.
(any_cast(const any&)): Use it and add an explicit cast for return.
(any_cast(any&)): Likewise.
(any_cast(any&&)): Likewise.
* testsuite/20_util/any/misc/any_cast.cc: Add a test for a type
that has an explicit copy constructor.
*testsuite/20_util/any/misc/any_cast_neg.cc: Adjust.
From-SVN: r243739
Implement P0504R0 (Revisiting in-place tag types for
any/optional/variant).
* include/std/any (any(_ValueType&& __value)): Constrain
the __is_in_place_type with the decayed type.
(make_any): Adjust to use the new tag type.
* include/std/utility (in_place_tag): Remove.
(in_place_t): Turn into a non-reference tag type.
(__in_place, __in_place_type, __in_place_index): Remove.
(in_place): Turn into an inline variable of non-reference
tag type.
(in_place<_Tp>): Remove.
(in_place_index<_Idx>): Remove.
(in_place_type_t): New.
(in_place_type): Turn into a variable template of non-reference
type.
(in_place_index_t): New.
(in_place_index): Turn into a variable template of non-reference
type.
* include/std/variant
(_Variant_storage(in_place_index_t<_Np>, _Args&&...)): Adjust to
use the new tag type.
(_Union(in_place_index_t<0>, _Args&&...)): Likewise.
(_Union(in_place_index_t<_Np>, _Args&&...)): Likewise.
(_Variant_base()): Likewise.
(variant(_Tp&&)): Likewise.
(variant(in_place_type_t<_Tp>, _Args&&...)): Likewise.
(variant(in_place_type_t<_Tp>, initializer_list<_Up>,
_Args&&...)): Likewise.
(variant(in_place_index_t<_Np>, _Args&&...)): Likewise.
(variant(in_place_index_t<_Np>, initializer_list<_Up>,
_Args&&...)): Likewise
(variant(allocator_arg_t, const _Alloc&)): Likewise.
(variant(allocator_arg_t, const _Alloc&, _Tp&&)): Likewise.
(variant(allocator_arg_t, const _Alloc&, in_place_type_t<_Tp>,
_Args&&...)): Likewise.
(variant(allocator_arg_t, const _Alloc&, in_place_type_t<_Tp>,
initializer_list<_Up>, _Args&&...)): Likewise.
(variant(allocator_arg_t, const _Alloc&, in_place_index_t<_Np>,
_Args&&...)): Likewise.
(variant(allocator_arg_t, const _Alloc&, in_place_index_t<_Np>,
initializer_list<_Up>, _Args&&...)): Likewise.
(emplace(_Args&&...)): Likewise.
(emplace(initializer_list<_Up>, _Args&&...)): Likewise.
* testsuite/20_util/any/cons/explicit.cc: Likewise.
* testsuite/20_util/any/cons/in_place.cc: Likewise.
* testsuite/20_util/any/requirements.cc: Add tests to
check that any is not constructible from the new in_place_type_t
of any value category.
* testsuite/20_util/in_place/requirements.cc: Adjust to
use the new tag type.
* testsuite/20_util/variant/compile.cc: Likewise.
* testsuite/20_util/variant/run.cc: Likewise.
From-SVN: r242401
don't copy the underlying value when any is moved,
make in_place constructors explicit.
* include/std/any (any(in_place_type_t<_ValueType>, _Args&&...)):
Make explicit.
(any(in_place_type_t<_ValueType>, initializer_list<_Up>, _Args&&...)):
Likewise.
(operator=(const any&)): Make strongly exception-safe.
(operator=(any&&)): reset() unconditionally in the case where
rhs has a value.
(operator=(_ValueType&&)): Indent the return type.
(_Manager_internal<_Tp>::_S_manage): Move in _Op_xfer, don't copy.
* testsuite/20_util/any/assign/2.cc: Adjust.
* testsuite/20_util/any/assign/exception.cc: New.
* testsuite/20_util/any/cons/2.cc: Adjust.
* testsuite/20_util/any/cons/explicit.cc: New.
* testsuite/20_util/any/misc/any_cast_neg.cc: Ajust.
From-SVN: r240951
