Several of the pb_ds headers are intended to be included multiple times,
within the definition of various class templates. The including files
define macros like PB_DS_CLASS_C_DEC and PB_DS_GEN_POS before including
these headers.
In some cases the types defined in the headers are actually nested types
within other classes, and so should not have been documented as though
they are declared in the global namespace, as in:
https://gcc.gnu.org/onlinedocs/gcc-8.3.0/libstdc++/api/a12028.html
In other cases the headers provide inline member function definitions,
but when processed by Doxygen the class name "PB_DS_CLASS_C_DEC" is not
recognised.
This patch makes Doxygen ignore definitions that only make sense when
included in the right context with the right macros defined.
* include/ext/pb_ds/detail/bin_search_tree_/*_imps.hpp: Do not define
anything unless PB_DS_CLASS_C_DEC is defined.
* include/ext/pb_ds/detail/binary_heap_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/binomial_heap_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/binomial_heap_base_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/cc_hash_table_map_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/gp_hash_table_map_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/hash_fn/*_imp.hpp: Likewise.
* include/ext/pb_ds/detail/left_child_next_sibling_heap_/*_imps.hpp:
Likewise.
* include/ext/pb_ds/detail/list_update_map_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/ov_tree_map_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/pairing_heap_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/pat_trie_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/rb_tree_map_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/rc_binomial_heap_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/resize_policy*_imp.hpp: Likewise.
* include/ext/pb_ds/detail/splay_tree_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/thin_heap_/*_imps.hpp: Likewise.
* include/ext/pb_ds/detail/trie_policy*_imp.hpp: Likewise.
* include/ext/pb_ds/detail/unordered_iterator/const_iterator.hpp:
Likewise.
* include/ext/pb_ds/detail/unordered_iterator/iterator.hpp: Likewise.
* include/ext/pb_ds/detail/unordered_iterator/point_const_iterator.hpp:
Likewise.
* include/ext/pb_ds/detail/unordered_iterator/point_iterator.hpp:
Likewise.
From-SVN: r270803
The current generic implementation of __complex_proj used when cproj is
not available calculates the wrong projection, giving a different result
than given by C99's cproj.
When C99 cproj is not available but isinf and copysign are, use those to
give correct results for float, double and long double. Otherwise, and
for other specializations of std::complex, just use a generic version
that returns its argument, and so doesn't support infinities.
We might want to consider adding additional overloads of __complex_proj
to support extended types such as _Float64x, _Float128 etc.
PR libstdc++/61761
* include/std/complex (__complex_proj): Return parameter unchanged.
[_GLIBCXX_USE_C99_COMPLEX] (__complex_proj): Change overloads for
floating-point types to take std::complex arguments.
[_GLIBCXX_USE_C99_MATH_TR1] (__complex_proj): Add overloads for
floating-point types.
* testsuite/26_numerics/complex/proj.cc: New test.
From-SVN: r270759
We already added it to the std::vector primary template.
* include/bits/stl_bvector.h (vector<bool>::empty()): Add nodiscard
attribute.
From-SVN: r270648
This class template has been unused since __gnu_debug::__base was
removed in r263786.
* include/bits/stl_iterator_base_types.h (_Iter_base): Remove unused
class template and partial specialization.
From-SVN: r270647
The standard only requires that _Size can be converted to an integral
type, not that it can be used for arithmetic. Add a new set of
__size_to_integer helper functions to do the conversion (which will be
ambiguous if there is no one conversion that is better than any others).
Also add tests for DR 426 which requires these algorithms and search_n
to handle negative values of n.
PR libstdc++/87982
* include/bits/stl_algo.h (generate_n): Convert _Size parameter to
an integral type.
* include/bits/stl_algobase.h (__size_to_integer): New overloaded
functions to convert a value to an integral type.
(__fill_n_a, __fill_n_a): Assert that __n is already an integral type.
(fill_n): Convert _Size parameter to an integral type.
* testsuite/25_algorithms/fill_n/dr426.cc: New test.
* testsuite/25_algorithms/generate_n/87982.cc: New test.
* testsuite/25_algorithms/generate_n/dr426.cc: New test.
From-SVN: r270646
2019-04-27 Marc Glisse <marc.glisse@inria.fr>
PR libstdc++/87106
* include/bits/stl_uninitialized.h (__relocate_object_a): Mark the
arguments with __restrict.
From-SVN: r270624
Jakub noted in https://gcc.gnu.org/ml/libstdc++/2019-04/msg00140.html
that an unwanted std::wstring::_M_replace_dispatch symbol has started to
be exported from the Fedora shared library. This symbol is triggered by
the instantiation of std::wstring::assign(const char*, const char*) from
std::__str_codecvt_in which is called from path::_S_convert_loc. The
branch that triggers that instantiation can't actually happen in that
case, because codecvt facets will only return noconv when the input and
output types are the same. Guarding the assign call with an if-constexpr
check that the types are the same avoids instantiating template
specializations that will never actually be needed.
* config/abi/pre/gnu.ver (GLIBCXX_3.4): Replace wildcard that matches
wstring::_M_replace_dispatch with more specific patterns.
* include/bits/fs_path.h (path::_S_convert_loc<_InputIterator>):
Create const std::string to avoid redundant call to _S_convert_loc
with non-const pointers.
* include/bits/locale_conv.h (__do_str_codecvt): Use if-constexpr to
avoid unnecessary basic_string::assign instantiations.
From-SVN: r270602
The 20_util/scoped_allocator/69293_neg.cc test was failing in C++2a mode
because the expected static_assert text wasn't matched. The code is
still ill-formed in C++2a, but uses the new __uses_alloc_args function
and so fails a different static_assert. This patch adds the same string
to the new static_assert, so the test passes.
Now that G++ allows concepts to be declared without 'bool' we can use
the correct C++2a syntax for the _Std_pair concept used to constrain the
uses-allocator construction utilities.
Also add a new test to verify that pmr::polymorphic_allocator correctly
performs recursive uses-allocator construction for nested pairs in
C++2a.
* include/std/memory (__uses_alloc_args): Add string-literal to
static_assert, to match the one in __uses_alloc.
[__cpp_concepts] (_Std_pair): Use C++2a syntax for concept.
* testsuite/20_util/polymorphic_allocator/construct_c++2a.cc: Check
for recursive uses-allocator construction of nested pairs.
* testsuite/20_util/scoped_allocator/construct_pair_c++2a.cc:: Add
comment.
From-SVN: r270600
PR libstdc++/90239
* doc/xml/manual/status_cxx2020.xml: Amend P0591R4 status.
* include/std/scoped_allocator [__cplusplus > 201703L]
(scoped_allocator_adaptor::construct): Define in terms of
uses_allocator_construction_args, as per P0591R4.
* testsuite/20_util/scoped_allocator/construct_pair_c++2a.cc: New test.
* testsuite/util/testsuite_allocator.h: Remove name of unused
parameter.
From-SVN: r270588
This change revealed two testsuite bugs where some string comparisons
only compiled by converting the strings to filesystem::path objects.
* include/bits/fs_path.h (operator<, operator<=, operator>)
(operator>=, operator==, operator!=): Make hidden friends, as per
LWG 3065.
* testsuite/27_io/filesystem/path/native/string-char8_t.cc: Fix
string type in test.
* testsuite/27_io/filesystem/path/native/string.cc: Likewise.
From-SVN: r270558
* include/std/tuple (apply): Use remove_reference_t instead of decay_t
as per P0777R1.
* include/std/type_traits (__result_of_memfun): Use remove_reference
instead of __remove_cvref_t and remove redundant is_same check.
(__inv_unwrap): Use __remove_cvref_t instead of decay_t.
From-SVN: r270551
The basic_string_view::pointer and basic_string_view::reference typedefs
are supposed to refer to the non-const value type.
In previous standards having traits_type::char_type different to
value_type was simply undefined, but in the C++2a draft it's ill-formed,
as changed by P1148R0. For std::basic_string and iostreams we might
want to only enforce this conditionally for __cplusplus > 201703L but
for std::basic_string_view we don't have backwards compatibility
concerns. Also add assertions to verify the _CharT argument is a
"char-like" type (non-array, trivial, standard layout type).
Also remove the non-standard basic_string_view::_M_check and
basic_string_view::_M_limit member functions, replacing them with
non-member functions that will still exist even if basic_string_view is
specialized by the program.
* include/experimental/string_view (basic_string_view::pointer)
(basic_string_view::reference): Fix to refer to non-const value_type.
* include/bits/basic_string.h (basic_string): Use __sv_check and
__sv_limit instead of basic_string_view::_M_check and
basic_string_view::_M_limit.
* include/std/string_view (__sv_check, __sv_limit): New
helper functions to replace basic_string_view::_M_check and
basic_string_view::_M_limit.
(basic_string_view): Add static assertions to enforce ill-formed
requirement for traits_type::char_type from P1148R0, and to enforce
required properties of char-like types.
(basic_string_view::pointer, basic_string_view::reference): Fix to
refer to non-const value_type.
(basic_string_view::operator[], basic_string_view::at)
(basic_string_view::front, basic_string_view::back)
(basic_string_view::data): Use const_reference and const_pointer
typedefs for return types.
(basic_string_view::_M_check, basic_string_view::_M_limit): Remove.
(hash<wstring_view>): Fix argument_type typedef.
* testsuite/21_strings/basic_string_view/modifiers/remove_prefix/
char/1.cc: Fix expected return type of basic_string_view::data().
* testsuite/21_strings/basic_string_view/modifiers/remove_prefix/
wchar_t/1.cc: Likewise.
* testsuite/21_strings/basic_string_view/modifiers/remove_suffix/
char/1.cc: Likewise.
* testsuite/21_strings/basic_string_view/modifiers/remove_suffix/
wchar_t/1.cc: Likewise.
* testsuite/21_strings/basic_string_view/requirements/traits_neg.cc:
New test.
* testsuite/21_strings/basic_string_view/requirements/typedefs.cc:
Check reference and pointer typedefs.
* testsuite/experimental/string_view/requirements/typedefs.cc:
Likewise.
* testsuite/experimental/string_view/modifiers/remove_prefix/char/1.cc:
Fix expected return type of basic_string_view::data().
* testsuite/experimental/string_view/modifiers/remove_prefix/wchar_t/
1.cc: Likewise.
* testsuite/experimental/string_view/modifiers/remove_suffix/char/1.cc:
Likewise.
* testsuite/experimental/string_view/modifiers/remove_suffix/wchar_t/
1.cc: Likewise.
From-SVN: r270548
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
* include/std/variant (__variant_construct): Use template parameter
type instead of equivalent decltype-specifier.
(_Move_ctor_base<false, Types...>::_Move_ctor_base(_Move_ctor_base&&)):
Replace forward with move.
(_Move_ctor_base<false, Types...>::_M_destructive_move)
(_Move_ctor_base<false, Types...>::_M_destructive_copy)
(_Move_ctor_base<true, Types...>::_M_destructive_move)
(_Move_ctor_base<true, Types...>::_M_destructive_copy): Only set the
index after construction succeeds.
(_Copy_assign_base<false, Types...>::operator=): Remove redundant
if-constexpr checks that are always true. Use __remove_cvref_t instead
of remove_reference so that is_nothrow_move_constructible check
doesn't use a const rvalue parameter. In the potentially-throwing case
construct a temporary and move assign it, as per LWG 2904.
(_Move_assign_base<false, Types...>::operator=): Remove redundant
if-constexpr checks that are always true. Use emplace as per LWG 2904.
(variant::operator=(T&&)): Only use emplace conditionally, otherwise
construct a temporary and move assign from it, as per LWG 2904.
* testsuite/20_util/variant/exception_safety.cc: Check that
assignment operators have strong exception safety guarantee.
From-SVN: r270525
The std::variant move assignment operator should not be trivial if the
variant is not trivially move constructible.
* include/std/variant (__detail::__variant::_Traits): Make
_S_trivial_copy_assign depend on _S_trivial_copy_ctor and make
_S_trivial_move_assign depend on _S_trivial_move_ctor, as per
P0602R4.
(__detail::__variant::_Copy_assign_alias): Only depend on
_S_trivial_copy_assign, which subsumes _S_trivial_copy_ctor now.
* testsuite/20_util/variant/compile.cc: Correct checks for trivial
move assignment operators.
From-SVN: r270510
Also refactor some constraints slightly to be more readable.
PR libstdc++/90165
* include/std/variant (variant::__not_self): New helper for the
is_same_v<remove_cvref_t<T>, variant>==false constraints.
(variant::__to_type_impl): Remove.
(variant::__to_type): Add default argument to check pack size, instead
of using __to_type_impl.
(variant::__accepted_type): Add default argument using __not_self.
(variant::__is_in_place_tag, variant::__not_in_place_tag): New helpers
for variant(T&&) constructor constraint.
(variant::variant(T&&)): Use __not_in_place_tag in constraints.
Extract __accepted_type into a named template parameter for reuse in
other constraints and in the exception specification.
(variant::variant(in_place_type_t<T>, Args&&...))
(variant::variant(in_place_type_t<T>, initializer_list<U>, Args&&...))
(variant::variant(in_place_index_t<T>, Args&&...))
(variant::variant(in_place_index_t<T>, initializer_list<U>, Args&&...))
(variant::operator=T&&)): Remove redundant && from trait arguments.
* testsuite/20_util/variant/compile.cc: Check variant(T&&) constructor
isn't used for in_place_type or in_place_index arguments.
From-SVN: r270509
The P0318R1 paper added to the C++2a draft recently was not the latest
version of the paper, and should have included these changes. These
changes will be made to the working draft via a Defect Report, so I'm
applying them to libstdc++ now.
* include/std/type_traits (unwrap_reference_t): Define for C++2a.
(unwrap_ref_decay): Remove inheritance from unwrap_reference.
* testsuite/20_util/unwrap_reference/1.cc: Adjust test to use alias.
From-SVN: r270506
A regression was introduced by the recent changes to provide the strong
exception safety guarantee for "never valueless" types that have O(1),
non-throwing move assignment. The problematic code is:
else if constexpr (__detail::__variant::_Never_valueless_alt<type>())
{
// This construction might throw:
variant __tmp(in_place_index<_Np>, __il,
std::forward<_Args>(__args)...);
// But _Never_valueless_alt<type> means this won't:
*this = std::move(__tmp);
}
When the variant is not assignable, the assignment is ill-formed, so
should not be attempted. When the variant has a copy assignment operator
but not a move assignment operator, the assignment performs a copy
assignment and that could throw, so should not be attempted.
The solution is to only take that branch when the variant has a move
assignment operator, which is determined by the _Traits::_S_move_assign
constant. When that is false the strong exception safety guarantee is
not possible, and so the __never_valueless function should also depend
on _S_move_assign.
While testing the fixes for this I noticed that the partial
specialization _Never_valueless_alt<basic_string<C,T,A>> incorrectly
assumed that is_nothrow_move_constructible<basic_string<C,T,A>> is
always true, but that's wrong for fully-dynamic COW strings. Fix the
partial specialization, and improve the comment describing
_Never_valueless_alt to be clear it depends on move construction as well
as move assignment.
Finally, I also observed that _Variant_storage<false, T...>::_M_valid()
was not taking advantage of the __never_valueless<T...>() function to
avoid a runtime check. Only the _Variant_storage<true, T...>::_M_valid()
function was using __never_valueless. That is also fixed.
PR libstdc++/87431
* include/bits/basic_string.h (_Never_valueless_alt): Make partial
specialization also depend on is_nothrow_move_constructible.
* include/std/variant (__detail::__variant::__never_valueless()):
Only true if the variant would have a move assignment operator.
(__detail::__variant::_Variant_storage<false, T...>::_M_valid()):
Check __never_valueless<T...>().
(variant::emplace): Only perform non-throwing move assignments
for never-valueless alternatives if the variant has a move assignment
operator.
* testsuite/20_util/variant/compile.cc: Check that never-valueless
types can be emplaced into non-assignable variants.
* testsuite/20_util/variant/run.cc: Check that never-valueless types
don't get copied when emplaced into non-assignable variants.
From-SVN: r270502
* include/pstl/algorithm_impl.h
(__internal::__brick_equal): use "4 iterator" version of
std::equal().
(__internal::__brick_equal): use simd for random access
iterators on unsequenced execution policies.
(__internal::__pattern_equal): add "4 iterator" version
(__internal::__pattern_equal): dispatch to simd __brick_equal
for vector-only execution policies.
(__internal::__pattern_equal): dispatch to __parallel_or for
parallel execution policies.
* include/pstl/glue_algorithm_impl.h
(std::equal): dispatch to "4 iterator" version of
__internal::__pattern_equal().
From-SVN: r270463
While testing the fix I also discovered that operator== assumes the
elements are comparable with operator!= which is not required.
PR libstdc++/90105
* include/bits/forward_list.h (operator==): Do not use operator!= to
compare elements.
(forward_list<T, A>::sort(Comp)): When elements are equal take the one
earlier in the list, so that sort is stable.
* testsuite/23_containers/forward_list/operations/90105.cc: New test.
* testsuite/23_containers/forward_list/comparable.cc: Test with
types that meet the minimum EqualityComparable and LessThanComparable
requirements. Remove irrelevant comment.
From-SVN: r270427
The standard says the std::variant copy constructor is defined as
deleted unless all alternative types are copy constructible, but we were
making it also depend on move constructible. Fix the condition and
enhance the tests to check the semantics with pathological copy-only
types (i.e. supporting copying but having deleted moves).
The enhanced tests revealed a regression in copy assignment for
non-trivial alternative types, where the assignment would not be
performed because the condition in the _Copy_assign_base visitor is
false: is_same_v<remove_reference_t<T&>, remove_reference_t<const T&>>.
* include/std/variant (__detail::__variant::_Traits::_S_copy_assign):
Do not depend on whether all alternative types are move constructible.
(__detail::__variant::_Copy_assign_base::operator=): Remove cv-quals
from the operand when deciding whether to perform the assignment.
* testsuite/20_util/variant/compile.cc (DeletedMoves): Define type
with deleted move constructor and deleted move assignment operator.
(default_ctor, copy_ctor, move_ctor, copy_assign, move_assign): Check
behaviour of variants with DeletedMoves as an alternative.
* testsuite/20_util/variant/run.cc (DeletedMoves): Define same type.
(move_ctor, move_assign): Check that moving a variant with a
DeletedMoves alternative falls back to copying instead of moving.
From-SVN: r270425
In C++1z drafts up to N4606 the constexpr keyword was missing from the
detailed description of this function, despite being shown in the class
synopsis. That was fixed editorially for N4618, but our implementation
was not corrected to match.
* include/std/optional (optional::value_or(U&&) &&): Add missing
constexpr specifier.
* testsuite/20_util/optional/constexpr/observers/4.cc: Check value_or
for disengaged optionals and rvalue optionals.
* testsuite/20_util/optional/observers/4.cc: Likewise.
From-SVN: r270409
This also replaces calls to __TBB_ASSERT so that there are two macro
definitions provided by c++config -
__PSTL_ASSERT(_Condition)
__PSTL_ASSERT_MSG(_Condition, _Message)
* include/bits/c++config:
Add definition for __PSTL_ASSERT.
Add definition for __PSTL_ASSERT_MSG.
* include/pstl/algorithm_impl.h: Replace use of assert().
* include/pstl/numeric_impl.h: Replace use of assert().
* include/pstl/parallel_backend_tbb.h:
Replace use of assert().
Replace use of __TBB_ASSERT().
* include/pstl/parallel_backend_utils.h: Replace use of assert().
From-SVN: r270293
* include/std/variant: Adjust whitespace. Add comments.
(_Multi_array): Leave primary template undefined.
(_Multi_array<_Tp>): Define partial specialization for base case of
recursion.
(__gen_vtable_impl, __gen_vtable): Remove redundant && from type
which is always a reference.
(__gen_vtable::_S_apply()): Remove function, inline body into
default member initializer.
* testsuite/20_util/variant/visit.cc: Test with noncopyable types.
From-SVN: r270238
The __visitor_result_type helper didn't use std::invoke and so didn't
compile when the visitor was a pointer-to-member rather than a function
object. Use std::invoke_result instead.
* include/std/variant (__variant_idx_cookie): Add member type.
(__visitor_result_type): Remove.
(__do_visit): Use invoke_result instead of __visitor_result_type.
* testsuite/20_util/variant/visit.cc: New test.
From-SVN: r270237
* include/std/variant (__do_visit): Add a template parameter
for enforcing same return types for visit.
(__gen_vtable_impl): Likewise.
(_S_apply_single_alt): Adjust.
(__visit_invoke_impl): New. Handle casting to void.
(__do_visit_invoke): New. Enforces same return types.
(__do_visit_invoke_r): New. Converts return types.
(__visit_invoke): Adjust.
(__gen_vtable): Add a template parameter for enforcing
same return types for visit.
* testsuite/20_util/variant/visit_r.cc: Add a test for a visitor with
different return types.
* testsuite/20_util/variant/visit_neg.cc: New. Ensures that
visitors with different return types don't accidentally
compile with regular visitation.
From-SVN: r270216
The equality operators for directory iterators are not explicitly
specified in the standard, they're only required to meet the iterator
requirements. This means we don't need to declare them at namespace
scope and can implement them as hidden friends.
Also add 'noexcept' to directory_iterator's dereference operators.
* include/bits/fs_dir.h (directory_iterator::operator*)
(directory_iterator::operator->): Add noexcept.
(operator==, operator!=): Replace namespace-scope equality operators
for directory iterators with hidden friends.
From-SVN: r270175
Implement the proposed resolution of LWG 2708 by moving the _M_options
and _M_pending members out of the recursive_directory_iterator into the
shared _Dir_stack object. Because _Dir_stack is an opaque type, the
member functions that access the _M_options and _M_pending variables
cannot be inline. Move them into the library.
As a drive-by fix, add noexcept to the non-throwing member functions of
recursive_directory_iterator.
* config/abi/pre/gnu.ver: Export new symbols.
* include/bits/fs_dir.h (recursive_directory_iterator::options())
(recursive_directory_iterator::recursion_pending())
(recursive_directory_iterator::disable_recursion_pending()): Remove
inline definitions. Make noexcept.
(recursive_directory_iterator::depth())
(recursive_directory_iterator::operator*())
(recursive_directory_iterator::operator->()): Make noexcept.
(recursive_directory_iterator::_M_options)
(recursive_directory_iterator::_M_pending): Remove data members.
* src/c++17/fs_path.cc (_Dir_stack): Add constructor and data members.
(recursive_directory_iterator::recursive_directory_iterator): Remove
ctor-initializer. Use new constructor for _Dir_stack.
(recursive_directory_iterator::options())
(recursive_directory_iterator::recursion_pending())
(recursive_directory_iterator::disable_recursion_pending()): Add
non-inline definitions.
(recursive_directory_iterator::depth()): Make noexcept.
(recursive_directory_iterator::increment(error_code&))
(recursive_directory_iterator::pop(error_code&)): Adjust to new
location of options and recursion_pending members.
* testsuite/27_io/filesystem/iterators/recursion_pending.cc: New test.
* testsuite/util/testsuite_fs.h (__gnu_test::scoped_file): Add
user-declared move constructor and assignment operator, to make the
type move-only.
From-SVN: r270173
The standard says "If *this and p are the same object, has no effect."
Previously we ended up clearing the path.
* include/bits/fs_path.h (path::operator=(path&&)): Check for self
assignment.
* src/c++17/fs_path.cc (path::operator=(const path&)): Likewise.
* testsuite/27_io/filesystem/path/assign/copy.cc: Test self
assignment.
From-SVN: r270171
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
The __glibcxx_assert macro should be used to check preconditions that
users must meet, not to check postconditions that the implementation
must meet. We have tests to verify std::variant meets its
postconditions, users shouldn't pay for those checks at runtime.
PR libstdc++/85184
* include/std/variant (_Copy_assign_base, _Move_assign_base, variant):
Remove assertions.
(variant::emplace<_Tp>): Remove result of emplace<N> directly.
From-SVN: r270117
These hash specializations should have been added when the pmr::string
and related typedefs were added.
* include/std/string (__hash_string_base): New class template defining
operator() for hashing strings.
(hash<pmr::string>, hash<pmr::u8string>, hash<pmr::u16string>)
(hash<pmr::u32string>, hash<pmr::wstring>): Define for C++17.
* testsuite/21_strings/basic_string/hash/hash.cc: New test.
* testsuite/21_strings/basic_string/hash/hash_char8_t.cc: New test.
From-SVN: r270116
Also use indices instead of types when checking whether
variants hold the same thing.
* include/std/variant (__do_visit): Add a template parameter
for index visitation, invoke with indices if index visitation
is used.
(__variant_idx_cookie): New.
(__visit_with_index): Likewise.
(_Copy_assign_base::operator=): Do single-visitation with
an index visitor.
(_Move_assign_base::operator=): Likewise.
(_Extra_visit_slot_needed): Adjust.
(__visit_invoke): Call with indices if it's an index visitor.
(relops): Do single-visitation with an index visitor.
(swap): Likewise.
(__visitor_result_type): New.
From-SVN: r270056
The static assertions added for PR libstdc++/48101 were at class scope
and so were evaluated too eagerly, when it might not be possible to
determine whether the function objects are invocable with the key types.
The problematic cases are where the key type is not known to be
convertible to the argument type(s) of the function object until later,
after a type has been completed. Specifically, if the key type is a
pointer to a derived class and the function object's argument type is a
pointer to a base class, then the derived-to-base conversion is only
valid once the derived type is complete.
By moving the static assertions to the destructor they will only be
evaluated when the destructor is instantiated, at which point whether
the key type can be passed to the function object should be knowable.
The ideal place to do the checks would be only when the function objects
are actually invoked, but that would mean adding the checks in numerous
places, so the destructor is used instead.
The tests need to be adjusted because the "required from here" line is
now the location of the destructor, not the point of instantiation in
the test file. For the map and multimap tests which check two
specializations, the dg-error matching the assertion text matches both
cases. Also check the diagnostic output for the template arguments, to
ensure both specializations trigger the assertion.
PR libstdc++/85965
* include/bits/hashtable.h (_Hashtable): Move static assertions to
destructor so they are not evaluated until the _Key type is complete.
* include/bits/stl_tree.h (_Rb_tree): Likewise.
* testsuite/23_containers/set/85965.cc: New test.
* testsuite/23_containers/unordered_set/85965.cc: New test.
* testsuite/23_containers/map/48101_neg.cc: Replace "here" errors
with regexp matching the corresponding _Rb_tree specialization.
* testsuite/23_containers/multimap/48101_neg.cc: Likewise.
* testsuite/23_containers/multiset/48101_neg.cc: Remove "here" error.
* testsuite/23_containers/set/48101_neg.cc: Likewise.
* testsuite/23_containers/unordered_map/48101_neg.cc: Likewise.
* testsuite/23_containers/unordered_multimap/48101_neg.cc: Likewise.
* testsuite/23_containers/unordered_multiset/48101_neg.cc: Likewise.
* testsuite/23_containers/unordered_set/48101_neg.cc: Likewise.
From-SVN: r269949
PR libstdc++/89825
Fix based on a suggestion by Antony Polukhin.
* include/std/variant (_Extra_visit_slot_needed): New.
(_Multi_array): Use it.
(_S_apply_all_alts): Likewise.
From-SVN: r269947
PR libstdc++/89824
Fix based on a suggestion by Antony Polukhin.
* include/std/variant (__gen_vtable): Don't reserve an
additional table slot, _Multi_array already does that.
From-SVN: r269941
