Commit Graph

7219 Commits

Author SHA1 Message Date
Thomas Rodgers
c24384efbb libstdc++: Fix for deadlock in std::counting_semaphore [PR100806]
libstdc++-v3/ChangeLog:
	PR libstdc++/100806
	* include/bits/semaphore_base.h (__atomic_semaphore::_M_release):
	Force _M_release() to wake all waiting threads.
	* testsuite/30_threads/semaphore/100806.cc: New test.

(cherry picked from commit e02840c1a9)
2021-06-22 11:07:58 -07:00
Jonathan Wakely
fe918041ce libstdc++: Replace incorrect static assertion in std::reduce [PR95833]
The standard does not require the iterator's value type to be
convertible to the result type, it only requires that the result of
dereferencing the iterator can be passed to the binary function.

libstdc++-v3/ChangeLog:

	PR libstdc++/95833
	* include/std/numeric (reduce(Iter, Iter, T, BinaryOp)): Replace
	incorrect static_assert with ones matching the 'Mandates'
	conditions in the standard.
	* testsuite/26_numerics/reduce/95833.cc: New test.

(cherry picked from commit 0532452dcd)
2021-06-18 16:55:09 +01:00
Jonathan Wakely
0191c74141 libstdc++: Simplify constexpr checks in std::char_traits [PR 91488]
This removes the 'static' keyword from the helper functions added by
r8-1294 to detect whether the char_traits member functions can be
evaluated at compile time. This prevents the "inlining failed" error
reported in the PR.

The new testcase from the PR is added to the libitm testsuite, because
that's where we can be sure it's OK to use the -fgnu-tm option.

As a drive-by fix, the feature test macros for C++20 P0980R1 support are
made to depend on whether __cpp_lib_is_constant_evaluated is defined.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

	PR libstdc++/91488

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (__cpp_lib_constexpr_string): Only
	define C++20 value when std::is_constant_evaluated is available.
	* include/bits/char_traits.h (__cpp_lib_constexpr_char_traits):
	Likewise.
	(__constant_string_p, __constant_array_p): Give external
	linkage.
	* include/std/version (__cpp_lib_constexpr_char_traits)
	(__cpp_lib_constexpr_string): Only define C++20 values when
	is_constant_evaluated is available.

libitm/ChangeLog:

	* testsuite/libitm.c++/libstdc++-pr91488.C: New test.

(cherry picked from commit b376b1ef38)
2021-06-18 11:16:52 +01:00
Patrick Palka
f0d8d001d9 libstdc++: Non-triv-copyable extra args aren't simple [PR100940]
This force-enables perfect forwarding call wrapper semantics whenever
the extra arguments of a partially applied range adaptor aren't all
trivially copyable, so as to avoid incurring unnecessary copies of
potentially expensive-to-copy objects (such as std::function objects)
when invoking the adaptor.

	PR libstdc++/100940

libstdc++-v3/ChangeLog:

	* include/std/ranges (__adaptor::_Partial): For the "simple"
	forwarding partial specializations, also require that
	the extra arguments are trivially copyable.
	* testsuite/std/ranges/adaptors/100577.cc (test04): New test.

(cherry picked from commit 2b87f3318c)
2021-06-17 22:55:34 -04:00
Patrick Palka
bc7a522548 libstdc++: Refine range adaptors' "simple extra args" mechanism [PR100940]
The _S_has_simple_extra_args mechanism is used to simplify forwarding
of range adaptor's extra arguments when perfect forwarding call wrapper
semantics isn't required for correctness, on a per-adaptor basis.
Both views::take and views::drop are flagged as such, but it turns out
perfect forwarding semantics are needed for these adaptors in some
contrived cases, e.g. when their extra argument is a move-only class
that's implicitly convertible to an integral type.

To fix this, we could just clear the flag for views::take/drop as with
views::split, but that'd come at the cost of acceptable diagnostics
for ill-formed uses of these adaptors (see PR100577).

This patch instead allows adaptors to parameterize their
_S_has_simple_extra_args flag according the types of the captured extra
arguments, so that we could conditionally disable perfect forwarding
semantics only when the types of the extra arguments permit it.  We
then use this finer-grained mechanism to safely disable perfect
forwarding semantics for views::take/drop when the extra argument is
integer-like, rather than incorrectly always disabling it.  Similarly,
for views::split, rather than always enabling perfect forwarding
semantics we now safely disable it when the extra argument is a scalar
or a view, and recover good diagnostics for these common cases.

	PR libstdc++/100940

libstdc++-v3/ChangeLog:

	* include/std/ranges (__adaptor::_RangeAdaptor): Document the
	template form of _S_has_simple_extra_args.
	(__adaptor::__adaptor_has_simple_extra_args): Add _Args template
	parameter pack.  Try to treat _S_has_simple_extra_args as a
	variable template parameterized by _Args.
	(__adaptor::_Partial): Pass _Arg/_Args to the constraint
	__adaptor_has_simple_extra_args.
	(views::_Take::_S_has_simple_extra_args): Templatize according
	to the type of the extra argument.
	(views::_Drop::_S_has_simple_extra_args): Likewise.
	(views::_Split::_S_has_simple_extra_args): Define.
	* testsuite/std/ranges/adaptors/100577.cc (test01, test02):
	Adjust after changes to _S_has_simple_extra_args mechanism.
	(test03): Define.

(cherry picked from commit 0f4a2fb44d)
2021-06-17 22:55:34 -04:00
Jonathan Wakely
3ae416e0a7 libstdc++: Fix common_reference for non-reference results [PR100894]
The result of COMMON-REF(A&, B&&) where they have no common reference
type should be ill-formed. Our implementation fails to check that the
COMMON-REF result is a reference, so is well-formed when it shouldn't
be. This means that common_reference uses that result when it shouldn't
do.

The fix is to reject the result of COMMON-REF(A, B) if it's not a
reference, so that common_reference falls through to the next case,
which uses COND-RES, which yields the correct non-reference result.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100894
	* include/std/type_traits (__common_ref_impl<X&, Y&>): Only
	use the type if it's a reference.
	* testsuite/20_util/common_reference/100894.cc: New test.

(cherry picked from commit c37b5ddcc8)
2021-06-14 21:34:33 +01:00
Jonathan Wakely
4f54fb7161 libstdc++: Do not use static_assert without message in C++11
libstdc++-v3/ChangeLog:

	* include/bits/random.tcc (__representable_as_double)
	(__p1_representable_as_double): Add "" to static asserts.

(cherry picked from commit 64ba45c76e)
2021-06-14 21:34:23 +01:00
Jonathan Wakely
028fd30231 libstdc++: Fix std::any constraints [PR101034]
PR libstdc++/101034

libstdc++-v3/ChangeLog:

	* include/std/any (any(in_place_t<T>, initializer_list<U>, A&&...))
	(any::emplace<T>(initializer_list<U>, A&&...)): Fix constraint
	to use lvalue.
	* testsuite/20_util/any/cons/101034.cc: New test.

(cherry picked from commit 14f26c75d2)
2021-06-14 15:11:22 +01:00
Jonathan Wakely
c4f1bbed3d libstdc++: Use reserved name for attribute [PR101055]
The no_unique_address attribute is not a reserved name until C++20, so
to use it in C++11/14/17 modes we should use the __no_unique_address_
form. We already use that form when using the attribute, but not in the
__has_cpp_attribute check.

libstdc++-v3/ChangeLog:

	PR libstdc++/101055
	* include/std/tuple: Use reserved form of attribute name.
	* testsuite/17_intro/headers/c++2011/all_attributes.cc: Add
	check for no_unique_address.
	* testsuite/17_intro/headers/c++2014/all_attributes.cc:
	Likewise.
	* testsuite/17_intro/headers/c++2017/all_attributes.cc:
	Likewise.

(cherry picked from commit 917efba2dd)
2021-06-14 12:10:52 +01:00
Patrick Palka
258aedd9ad libstdc++: Fix up semiregular-box partial specialization [PR100475]
This makes the in-place constructor of our partial specialization of
__box for already-semiregular types perform direct-non-list-initialization
(in accordance with the specification of the primary template), and
additionally makes the member function data() use std::__addressof.

libstdc++-v3/ChangeLog:

	PR libstdc++/100475
	* include/std/ranges (__box::__box): Use non-list-initialization
	in member initializer list of in-place constructor of the
	partial specialization for semiregular types.
	(__box::operator->): Use std::__addressof.
	* testsuite/std/ranges/adaptors/detail/semiregular_box.cc
	(test02): New test.
	* testsuite/std/ranges/single_view.cc (test04): New test.

(cherry picked from commit fe993b469c)
2021-06-13 23:19:49 -04:00
Jonathan Wakely
828cdc6429 libstdc++: Fix filesystem::path comparisons for C++23
In C++23 there is a basic_string_view(Range&&) constructor, which is
constrained to take a range (specifically, a contiguous_range). When the
filesystem::path comparison operators call lhs.compare(rhs) the overload
taking a string_view is considered, which means checking whether path
satisfies the range concept. That satisfaction result changes depending
whether path::iterator is complete, which is ill-formed; no diagnostic
required. To avoid the problem, this change ensures that the overload
resolution is performed in a context where path::iterator is complete
and the range concept is satisfied. (The result of overload resolution
is always that the compare(const path&) overload is the best match, but
we still have to consider the compare(basic_string_view<value_type>) one
to decide if it even participates in overload resolution).

For std::filesystem::path we can't define the comparison operators later
in the file, because they are hidden friends, so a new helper is
introduced that gets defined when everything else is complete.

For std::experimental::filesystem::path we can just move the definitions
of the comparison operators later in the file.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/fs_path.h (operator==, operator<=>): Use new
	_S_compare function.
	(path::_S_compare): New function to call path::compare in a
	context where path::iterator is complete.
	* include/experimental/bits/fs_path.h (operator<, operator==):
	Define after path::iterator is complete.
	* testsuite/27_io/filesystem/path/native/conv_c++23.cc: New
	test.
	* testsuite/experimental/filesystem/path/native/conv_c++23.cc:
	New test.

(cherry picked from commit 1e690757d3)
2021-06-11 23:23:57 +01:00
Jonathan Wakely
ef636c0005 libstdc++: Finish implementing LWG 3413 for propagate_const
We already have conditional noexcept so this just constrains the
non-member swap overload.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/experimental/propagate_const (swap): Constrain.
	* testsuite/experimental/propagate_const/swap/lwg3413.cc: New test.

(cherry picked from commit d319517e80)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
e198d93d49 libstdc++: Fix constraint on std::optional assignment [PR 100982]
libstdc++-v3/ChangeLog:

	PR libstdc++/100982
	* include/std/optional (optional::operator=(const optional<U>&)):
	Fix value category used in is_assignable check.
	* testsuite/20_util/optional/assignment/100982.cc: New test.

(cherry picked from commit b3fce1bd45)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
4f11586945 libstdc++: Constrain three-way comparison for std::optional [PR 98842]
The operator<=>(const optional<T>&, const U&) operator is supposed to be
constrained with three_way_comparable_with<U, T> so that it can only be
used when T and U are weakly-equality-comparable and also three-way
comparable.

Adding that constrain completely breaks std::optional comparisons,
because it causes constraint recursion. To avoid that, an additional
check that U is not a specialization of std::optional is needed. That
appears to be a defect in the standard and should be reported to LWG.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/98842
	* include/std/optional (operator<=>(const optional<T>& const U&)):
	Add missing constraint and add workaround for template
	recursion.
	* testsuite/20_util/optional/relops/three_way.cc: Check that
	type without equality comparison cannot be compared when wrapped
	in std::optional.

(cherry picked from commit adec148117)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
2ba1680d3e libstdc++: Fix return type of ranges::ssize for 128-bit integer [PR 100824]
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/ranges_base.h (_SSize): Return signed type.
	* testsuite/std/ranges/access/ssize.cc: Check with __int128.

(cherry picked from commit 96963713f6)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
1112f1226a libstdc++: Implement LWG 3403 for std::ranges::ssize
I already changed the constraints for ranges::ssize to use ranges::size,
this implements the rest of LWG 3403, so that the returned type is the
signed type corresponding to the result of ranges::size.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h (_SSize): Return the result of
	ranges::size converted to the wider of make-signed-like-t<S> and
	ptrdiff_t, rather than the ranges different type.
	* testsuite/std/ranges/access/ssize.cc: Adjust expected result
	for an iota_view that uses an integer class type for its
	difference_type.

(cherry picked from commit 621ea10ca0)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
9505359158 libstdc++: Fix helper concept for ranges::data [PR 100824]
We need to decay the result of t.data() before checking if it's a
pointer.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/ranges_base.h (__member_data): Use __decay_copy.
	* testsuite/std/ranges/access/data.cc: Add testcase from PR.

(cherry picked from commit 3e5f2425f8)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
a842cb9c25 libstdc++: Fix value categories used by ranges access CPOs [PR 100824]
The implementation of P2091R0 was incomplete, so that some range access
CPOs used perfect forwarding where they should not. This fixes it by
consistently operating on lvalues.

Some additional changes that are not necessary to fix the bug:

Modify the __as_const helper to simplify its usage. Instead of deducing
the value category from its argument, and requiring callers to forward
the argument as the correct category, add a non-deduced template
parameter which is used for the value category and accept the argument
as an lvalue. This means callers say __as_const<T>(t) instead of
__as_const(std::forward<T>(t)).

Always use an lvalue reference type as the template argument for the
_S_noexcept helpers, so that we only instantiate one specialization for
lvalues and rvalues of the same type.

Move some helper concepts and functions from namespace std::__detail
to ranges::__cust_access, to be consistent with the ranges::begin CPO.
This ensures that the __adl_begin concept and the _Begin::operator()
function are in the same namespace, so unqualified lookup is consistent
and the poison pills for begin are visible to both.

Simplified static assertions for arrays, because the expression a+0 is
already ill-formed for an array of incomplete type.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/iterator_concepts.h (__detail::__decay_copy)
	(__detail::__member_begin, __detail::__adl_begin): Move to
	namespace ranges::__cust_access.
	(__detail::__ranges_begin): Likewise, and rename to __begin.
	Remove redundant static assertion.
	* include/bits/ranges_base.h (_Begin, _End, _RBegin, _REnd):
	Use lvalue in noexcept specifier.
	(__as_const): Add non-deduced parameter for value category.
	(_CBegin, _CEnd, _CRBegin, _CREnd, _CData): Adjust uses of
	__as_const.
	(__member_size, __adl_size, __member_empty, __size0_empty):
	(__eq_iter_empty, __adl_data): Use lvalue objects in
	requirements.
	(__sentinel_size): Likewise. Add check for conversion to
	unsigned-like.
	(__member_data): Allow non-lvalue types to satisfy the concept,
	but use lvalue object in requirements.
	(_Size, _SSize): Remove forwarding to always use an lvalue.
	(_Data): Likewise. Add static assertion for arrays.
	* testsuite/std/ranges/access/cdata.cc: Adjust expected
	behaviour for rvalues. Add negative tests for ill-formed
	expressions.
	* testsuite/std/ranges/access/data.cc: Likewise.
	* testsuite/std/ranges/access/empty.cc: Adjust expected
	behaviour for rvalues.
	* testsuite/std/ranges/access/size.cc: Likewise.

(cherry picked from commit ee9548b36a)
2021-06-11 23:23:55 +01:00
Jonathan Wakely
3a401ff88a libstdc++: Add feature test macro for heterogeneous lookup in unordered containers
Also update the C++20 status docs.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* doc/xml/manual/status_cxx2020.xml:
	* doc/html/*: Regenerate.
	* include/bits/hashtable.h (__cpp_lib_generic_unordered_lookup):
	Define.
	* include/std/version (__cpp_lib_generic_unordered_lookup):
	Define.
	* testsuite/23_containers/unordered_map/operations/1.cc: Check
	feature test macro.
	* testsuite/23_containers/unordered_set/operations/1.cc:
	Likewise.

(cherry picked from commit f78f25f438)
2021-06-11 23:23:55 +01:00
Patrick Palka
80495610eb libstdc++: Simplify range adaptors' forwarding of bound args [PR100577]
r11-8053 rewrote the range adaptor implementation in conformance with
P2281R1, making partial application act like a SFINAE-friendly perfect
forwarding call wrapper.  Making SFINAE-friendliness coexist with
perfect forwarding here requires adding fallback deleted operator()
overloads (as described in e.g. section 5.5 of P0847R6).  But
unfortunately, as reported in PR100577, this necessary technique of
using of deleted overloads regresses diagnostics for ill-formed calls to
partially applied range adaptors in GCC.

Although GCC's diagnostics can arguably be improved here by having the
compiler explain why the other candidates weren't viable when overload
resolution selects a deleted candidate, we can also largely work around
this on the library side (and achieve more concise diagnostics than by
a frontend-side improvement alone) if we take advantage of the
observation that not all range adaptors need perfect forwarding call
wrapper semantics, in fact only views::split currently needs it, because
all other range adaptors either take no extra arguments or only
arguments that are expected to be freely/cheaply copyable, e.g. function
objects and integer-like types.  (The discussion section in P2281R1 goes
into detail about why views::split is special.)

To that end, this introduces opt-in flags for denoting a range adaptor
as having "simple" extra arguments (in the case of a range adaptor
non-closure) or having a "simple" call operator (in the case of a range
adaptor closure).  These flags are then used to conditionally simplify
the operator() for the generic _Partial and _Pipe class templates, down
from needing three overloads thereof (including one defined as deleted)
to just needing a single overload.  The end result is that diagnostic
quality is restored for all adaptors except for views::split, and
diagnostics for the adaptors are generally made more concise since
there's only a single _Partial/_Pipe overload to diagnose instead of
three of them.

libstdc++-v3/ChangeLog:

	PR libstdc++/100577
	* include/std/ranges (_RangeAdaptorClosure): Document
	_S_has_simple_call_op mechanism.
	(_RangeAdaptor): Document _S_has_simple_extra_args mechanism.
	(__closure_has_simple_call_op): New concept.
	(__adaptor_has_simple_extra_args): Likewise.
	(_Partial<_Adaptor, _Args...>): New partial specialization.
	(_Partial<_Adaptor, _Arg>): Likewise.
	(_Pipe<_Lhs, _Rhs>): Likewise.
	(views::_All::_S_has_simple_call_op): Define to true.
	(views::_Filter::_S_has_simple_extra_args): Likewise.
	(views::_Transform::_S_has_simple_extra_args): Likewise.
	(views::_Take::_S_has_simple_extra_args): Likewise.
	(views::_TakeWhile::_S_has_simple_extra_args): Likewise.
	(views::_Drop::_S_has_simple_extra_args): Likewise.
	(views::_DropWhile::_S_has_simple_extra_args): Likewise.
	(views::_Join::_S_has_simple_call_op): Likewise.
	(views::_Split): Document why we don't define
	_S_has_simple_extra_args to true for this adaptor.
	(views::_Common::_S_has_simple_call_op): Define to true.
	(views::_Reverse::_S_has_simple_call_op): Likewise.
	(views::_Elements::_S_has_simple_call_op): Likewise.
	* testsuite/std/ranges/adaptors/100577.cc: New test.

(cherry picked from commit 57ed620ebf)
2021-06-10 17:24:22 -04:00
Patrick Palka
a35c5a5fc3 libstdc++: Avoid hard error in ranges::unique_copy [PR100770]
Here, in the constexpr if condition within ranges::unique_copy, when
input_iterator<_Out> isn't satisfied we must avoid substituting into
iter_value_t<_Out> because the latter isn't necessarily well-formed
then.  To that end, this patch factors out the condition into a concept
and uses it throughout.

This patch also makes the definition of our testsuite
output_iterator_wrapper more minimal by setting its value_type, pointer
and reference member types to void.  This means our existing tests for
unique_copy already exercise the fix for this bug, so we don't need
to add another test.  The only other fallout of this testsuite iterator
change appears in std/ranges/range.cc, where the use of range_value_t
on a test_output_range is now ill-formed.

	PR libstdc++/100770

libstdc++-v3/ChangeLog:

	* include/bits/ranges_algo.h (__detail::__can_reread_output):
	Factor out this concept from ...
	(__unique_copy_fn::operator()): ... here.  Use the concept
	throughout.
	* testsuite/std/ranges/range.cc: Remove now ill-formed use
	of range_value_t on an output_range.
	* testsuite/util/testsuite_iterators.h (output_iterator_wrapper):
	Define value_type, pointer and reference member types to void.

(cherry picked from commit 0614bbbe59)
2021-06-10 16:59:34 -04:00
Patrick Palka
c6ccaf17dd libstdc++: Fix access issue in iota_view::_Sentinel [PR100690]
libstdc++-v3/ChangeLog:

	PR libstdc++/100690
	* include/std/ranges (iota_view::_Sentinel::_M_distance_from):
	Split out this member function from ...
	(iota_view::_Sentinel::operator-): ... here, for sake of access
	control.
	* testsuite/std/ranges/iota/iota_view.cc (test05): New test.

(cherry picked from commit 317a38cd46)
2021-06-10 15:15:54 -04:00
Patrick Palka
e3804ba98f libstdc++: Implement LWG 3533 changes to foo_view::iterator::base()
libstdc++-v3/ChangeLog:

	* include/std/ranges (filter_view::_Iterator::base): Make the
	const& overload unconstrained and return a const reference as
	per LWG 3533.  Make unconditionally noexcept.
	(transform_view::_Iterator::base): Likewise.
	(elements_view::_Iterator::base): Likewise.

(cherry picked from commit eb1aa9ad2a)
2021-06-10 14:58:53 -04:00
Patrick Palka
048eb89a1e libstdc++: Implement LWG 3391 changes to move/counted_iterator::base()
libstdc++-v3/ChangeLog:

	* include/bits/stl_iterator.h (move_iterator::base): Make the
	const& overload unconstrained and return a const reference as
	per LWG 3391.  Make unconditionally noexcept.
	(counted_iterator::base): Likewise.
	* testsuite/24_iterators/move_iterator/lwg3391.cc: New test.
	* testsuite/24_iterators/move_iterator/move_only.cc: Adjust
	has_member_base concept to decay-copy the result of base().

(cherry picked from commit 08f3287eef)
2021-06-10 14:58:53 -04:00
Patrick Palka
3b93d61be5 libstdc++: Fix access issue in elements_view::_Sentinel [PR100631]
In the earlier commit r12-854 I forgot to also rewrite the other operator-
overload in terms of the split-out member function _M_distance_from.

libstdc++-v3/ChangeLog:

	PR libstdc++/100631
	* include/std/ranges (elements_view::_Sentinel::operator-): Use
	_M_distance_from in the other operator- overload too.
	* testsuite/std/ranges/adaptors/elements.cc (test06): Augment test.

(cherry picked from commit 38751c4d5e)
2021-06-10 14:51:40 -04:00
Patrick Palka
fd4db3ddc3 libstdc++: Fix miscellaneous issues with elements_view::_Sentinel [PR100631]
libstdc++-v3/ChangeLog:

	PR libstdc++/100631
	* include/std/ranges (elements_view::_Iterator): Also befriend
	_Sentinel<!_Const>.
	(elements_view::_Sentinel::_M_equal): Templatize.
	(elements_view::_Sentinel::_M_distance_from): Split out from ...
	(elements_view::_Sentinel::operator-): ... here.  Depend on
	_Base2 instead of _Base in the return type.
	* testsuite/std/ranges/adaptors/elements.cc (test06, test07):
	New tests.

(cherry picked from commit 2e2eef80ac)
2021-06-10 14:51:40 -04:00
Patrick Palka
a50cc70f1b libstdc++: Implement missing P0896R4 changes to reverse_iterator [PR100639]
This implements the P0896R4 changes to reverse_iterator's member types
value_type, difference_type and reference in C++20 mode, which fixes
taking the reverse_iterator of an iterator with a non-integral
difference_type (such as iota_view<long long>).

libstdc++-v3/ChangeLog:

	PR libstdc++/100639
	* include/bits/stl_iterator.h (reverse_iterator::difference_type):
	In C++20 mode, define in terms of iter_difference_t as per P0896R4.
	(reverse_iterator::reference): Likewise, but with iter_reference_t.
	(reverse_iterator::value_type): Likewise, but with iter_value_t.
	* testsuite/std/ranges/adaptors/reverse.cc (test08): New test.
	* testsuite/24_iterators/reverse_iterator/100639.cc: New test.

(cherry picked from commit d5cbe0f0d4)
2021-06-10 14:37:29 -04:00
Thomas Rodgers
d746294538 libstdc++: Fix Wrong param type in :atomic_ref<_Tp*>::wait [PR100889]
libstdc++-v3/ChangeLog:

	PR libstdc++/100889
	* include/bits/atomic_base.h (atomic_ref<_Tp*>::wait):
	Change parameter type from _Tp to _Tp*.
	* testsuite/29_atomics/atomic_ref/wait_notify.cc: Extend
	coverage of types tested.

(cherry picked from commit 25e5ecdf82)
2021-06-08 16:01:48 -07:00
Thomas Rodgers
7976eccf5f [libstdc++] Remove unused hasher instance.
This is a remnant of poorly executed refactoring.

libstdc++-v3/ChangeLog:

	* include/std/barrier (__tree_barrier::_M_arrive): Remove
	unnecessary hasher instantiation.

(cherry picked from commit 16a8e18858)
2021-06-08 15:45:52 -07:00
Avi Kivity
23fa1e7eab libstdc++: add missing typename for dependent type in ranges::elements_view [PR100900]
Clang complains about the missing typename. I believe it's not required
in a more complete implementation of C++, but it's nicer to support
less complete implementations.

	PR libstdc++/100900

libstdc++-v3/ChangeLog:

	* include/std/ranges (elements_view::__iter_cat::_S_iter_cat):
	Add missing typename.

(cherry picked from commit 5e2e15f212)
2021-06-07 11:21:37 -04:00
Jonathan Wakely
10c58754a8 libstdc++: Use __builtin_unreachable for constexpr assertions [PR 100676]
The current implementation of compile-time precondition checks causes
compilation to fail by calling a non-constexpr function declared at
block scope. This breaks the CUDA compiler, which wraps some libstdc++
headers in a pragma that declares everything as a __host__ __device__
function, but others are not wrapped and so everything is a __host__
function. The local declaration thus gets redeclared as two different
types of function, which doesn't work.

Just use __builtin_unreachable to make constant evaluation fail, instead
of the local function declaration. Also simplify the assertion macros,
which has the side effect of giving simpler compilation errors when
using Clang.

libstdc++-v3/ChangeLog:

	PR libstdc++/100676
	* include/bits/c++config (__glibcxx_assert_1): Rename to ...
	(__glibcxx_constexpr_assert): ... this.
	(__glibcxx_assert_impl): Use __glibcxx_constexpr_assert.
	(__glibcxx_assert): Define as either __glibcxx_constexpr_assert
	or __glibcxx_assert_impl.
	(__glibcxx_assert_2): Remove
	* include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_AT_F): Use
	__glibcxx_constexpr_assert instead of __glibcxx_assert_1.
	* testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc:
	Adjust expected error.
	* testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc:
	Likewise.
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc:
	Likewise.
	* testsuite/23_containers/span/back_neg.cc: Likewise.
	* testsuite/23_containers/span/front_neg.cc: Likewise.
	* testsuite/23_containers/span/index_op_neg.cc: Likewise.

(cherry picked from commit 6b42b5a8a2)
2021-06-02 14:43:20 +01:00
Jonathan Wakely
88ed4abb35 libstdc++: Fix return value of std::ranges::advance [PR 100833]
The three-argument form of ranges::advance is supposed to return the
difference between the second argument and the distance the iterator was
advanced. When a non-random-access iterator is not advanced (because it
already equals the sentinel) we were returning 0 rather than n - 0.

libstdc++-v3/ChangeLog:

	PR libstdc++/100833
	* include/bits/ranges_base.h (ranges::advance(iter, n, sentinel)):
	Fix return value for no-op case.
	* testsuite/24_iterators/range_operations/advance.cc: Test
	return values of three-argument overload.

(cherry picked from commit d832629169)
2021-06-02 14:43:20 +01:00
Jonathan Wakely
f2b76257e9 libstdc++: Change [range.iter.op] functions to function objects [PR 100768]
The standard specifies std::ranges::distance etc as function templates,
but it also requires them to not be found by ADL, and to suppress ADL
when normal unqualified lookup does find them. That means they need to
be function objects.

libstdc++-v3/ChangeLog:

	PR libstdc++/100768
	* include/bits/ranges_base.h (advance, distance, next, prev):
	Replace function templates with function objects.
	* testsuite/24_iterators/headers/iterator/synopsis_c++20.cc:
	Adjust for changes to function objects.
	* testsuite/std/ranges/adaptors/elements.cc: Add using
	declarations for names from namespace ranges.
	* testsuite/std/ranges/adaptors/transform.cc: Likewise.
	* testsuite/24_iterators/range_operations/100768.cc: New test.

(cherry picked from commit a49a045b92)
2021-06-02 14:43:19 +01:00
Patrick Palka
e1489a3d61 libstdc++: Implement P2328 changes to join_view
This implements the wording changes of P2328R0 "join_view should join
all views of ranges".

libstdc++-v3/ChangeLog:

	* include/std/ranges (__detail::__non_propating_cache): Define
	as per P2328.
	(join_view): Remove constraints on the value and reference types
	of the wrapped iterator type as per P2328.
	(join_view::_Iterator::_M_satisfy): Adjust as per P2328.
	(join_view::_Iterator::operator++): Likewise.
	(join_view::_M_inner): Use __non_propating_cache as per P2328.
	Remove now-redundant use of __maybe_present_t.
	* testsuite/std/ranges/adaptors/join.cc: Include <array>.
	(test10): New test.

(cherry picked from commit 237dde3d03)
2021-05-28 10:29:47 -04:00
Patrick Palka
49f369fb33 libstdc++: Fix iterator caching inside range adaptors [PR100479]
This fixes two issues with our iterator caching as described in detail
in the PR.  Since we recently added the __non_propagating_cache class
template as part of r12-336 for P2328, this patch just rewrites the
problematic _CachedPosition partial specialization in terms of this
class template.

For the offset partial specialization, it's safe to propagate the cached
offset on copy/move, but we should still invalidate the cached offset in
the source object on move.

libstdc++-v3/ChangeLog:

	PR libstdc++/100479
	* include/std/ranges (__detail::__non_propagating_cache): Move
	definition up to before that of _CachedPosition.  Make base
	class _Optional_base protected instead of private.  Add const
	overload for operator*.
	(__detail::_CachedPosition): Rewrite the partial specialization
	for forward ranges as a derived class of __non_propagating_cache.
	Remove the size constraint on the partial specialization for
	random access ranges.  Add copy/move/copy-assignment/move-assignment
	members to the offset partial specialization for random
	access ranges that propagate the cached value but additionally
	invalidate it in the source object on move.
	* testsuite/std/ranges/adaptors/100479.cc: New test.

(cherry picked from commit 46ed811bcb)
2021-05-28 10:20:18 -04:00
Joern Rennecke
5f772bd984 libstdc++: Disable floating_to_chars.cc on 16 bit targets
This patch conditionally disables the compilation of floating_to_chars.cc
on 16 bit targets, thus fixing a build failure for these targets as
the POW10_SPLIT_2 array exceeds the maximum object size.

libstdc++-v3/
	PR libstdc++/100361
	* include/std/charconv (to_chars): Hide the overloads for
	floating-point types for 16 bit targets.
	* src/c++17/floating_to_chars.cc: Don't compile for 16 bit targets.
	* testsuite/20_util/to_chars/double.cc: Run this test only on
	size32plus targets.
	* testsuite/20_util/to_chars/float.cc: Likewise.
	* testsuite/20_util/to_chars/long_double.cc: Likewise.
2021-05-20 13:41:13 +01:00
Jonathan Wakely
f8d2cef5c5 libstdc++: Fix filesystem::path constraints for volatile [PR 100630]
The constraint check for filesystem::path construction uses
decltype(__is_path_src(declval<Source>())) which mean it considers
conversion from an rvalue.  When Source is a volatile-qualified type
it cannot use is_path_src(const Unknown&) because a const lvalue
reference can only bind to a non-volatile rvalue.

Since the relevant path members all have a const Source& parameter,
the constraint should be defined in terms of declval<const Source&>(),
not declval<Source>(). This avoids the problem of volatile-qualified
rvalues, because we no longer use an rvalue at all.

libstdc++-v3/ChangeLog:

	PR libstdc++/100630
	* include/experimental/bits/fs_path.h (__is_constructible_from):
	Test construction from a const lvalue, not an rvalue.
	* testsuite/27_io/filesystem/path/construct/100630.cc: New test.
	* testsuite/experimental/filesystem/path/construct/100630.cc:
	New test.

(cherry picked from commit 45aa7a4476)
2021-05-17 21:52:19 +01:00
Thomas Rodgers
2b57186100 libstdc++: Fix wrong thread waking on notify [PR100334]
Fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100334

libstdc++-v3/ChangeLog:
	* include/bits/atomic_wait.h (__waiter::_M_do_wait_v): loop
	until value change observed.
	(__waiter_base::_M_laundered): New member.
	(__waiter_base::_M_notify): Check _M_laundered to determine
	whether to wake one or all.
	(__detail::__atomic_compare): Return true if call to
	__builtin_memcmp() == 0.
	(__waiter_base::_S_do_spin_v): Adjust predicate.
	* testsuite/29_atomics/atomic/wait_notify/100334.cc: New
	test.

(cherry picked from commit 346cbaf578)
2021-05-17 12:06:51 -07:00
Patrick Palka
e3c9eb860c libstdc++: Implement P2367 changes to avoid some list-initialization
This implements the wording changes of P2367R0 "Remove misuses of
list-initialization from Clause 24", modulo the parts that depend
on P1739R4 which we don't yet implement (due to LWG 3407).

libstdc++-v3/ChangeLog:

	* include/bits/ranges_util.h (subrange::subrange): Avoid
	list-initialization in delegating constructor.
	* include/std/ranges (single_view): Replace implicit guide
	with explicit deduction guide that decays its argument.
	(_Single::operator()): Avoid CTAD when constructing the
	single_view object.
	(_Iota::operator()): Avoid list-initialization.
	(__detail::__can_filter_view, _Filter::operator()): Likewise.
	(__detail::__can_transform_view, _Transform::operator()): Likewise.
	(take_view::begin): Likewise.
	(__detail::__can_take_view, _Take::operator()): Likewise.
	(__detail::__can_take_while_view, _TakeWhile::operator()): Likewise.
	(__detail::__can_drop_view, _Drop::operator()): Likewise.
	(__detail::__can_drop_while_view, _DropWhile::operator()): Likewise.
	(split_view::split_view): Use views::single when initializing
	_M_pattern.
	(__detail::__can_split_view, _Split::operator()): Avoid
	list-initialization.
	(_Counted::operator()): Likewise.
	* testsuite/std/ranges/p2367.cc: New test.

(cherry picked from commit 6e00d9bb11)
2021-05-12 14:02:57 -04:00
Jonathan Wakely
db9dec545b libstdc++: Fix missing members in std::allocator<void>
The changes in 75c6a925da were slightly
incorrect, because the converting constructor should be noexcept, and
the POCMA and is_always_equal traits should still be present in C++20.
This fixes it, and slightly refactors the preprocessor conditions and
order of members. Also add comments explaining things.

The non-standard construct and destroy members added for PR 78052 can be
private if allocator_traits<allocator<void>> is made a friend.

libstdc++-v3/ChangeLog:

	* include/bits/allocator.h (allocator<void>) [C++20]: Add
	missing noexcept to constructor. Restore missing POCMA and
	is_always_equal_traits.
	[C++17]: Make construct and destroy members private and
	declare allocator_traits as a friend.
	* include/bits/memoryfwd.h (allocator_traits): Declare.
	* include/ext/malloc_allocator.h (malloc_allocator::allocate):
	Add nodiscard attribute. Add static assertion for LWG 3307.
	* include/ext/new_allocator.h (new_allocator::allocate): Add
	static assertion for LWG 3307.
	* testsuite/20_util/allocator/void.cc: Check that converting
	constructor is noexcept. Check for propagation traits and
	size_type and difference_type. Check that pointer and
	const_pointer are gone in C++20.

(cherry picked from commit 5e3a1ea3d8)
2021-05-11 20:50:09 +01:00
Jonathan Wakely
16255fd2fd libstdc++: Remove TODO comment
We have a comment saying to replace the simple binary_semaphore type
with std::binary_semaphore, which has been done. However, that isn't
defined on all targets. So keep the simple one here that just implements
the parts of the API needed by <stop_token>, and remove the comment
suggesting it should be replaced.

libstdc++-v3/ChangeLog:

	* include/std/stop_token: Remove TODO comment.

(cherry picked from commit 151154a21d)
2021-05-11 20:50:09 +01:00
Jonathan Wakely
66b308931e libstdc++: Implement proposed resolution to LWG 3548
This has been tentatively approved by LWG. The deleter from a unique_ptr
can be moved into the shared_ptr (at least, since LWG 2802). This uses
std::forward<_Del>(__r.get_deleter()) not std::move(__r.get_deleter())
because we don't want to convert the deleter to an rvalue when _Del is
an lvalue reference type.

This also adds a missing is_move_constructible_v<D> constraint to the
shared_ptr(unique_ptr<Y, D>&&) constructor, which is inherited from the
shared_ptr(Y*, D) constructor due to the use of "equivalent to" in the
specified effects.

libstdc++-v3/ChangeLog:

	* include/bits/shared_ptr_base.h (__shared_count(unique_ptr&&)):
	Initialize a non-reference deleter from an rvalue, as per LWG
	3548.
	(__shared_ptr::_UniqCompatible): Add missing constraint.
	* testsuite/20_util/shared_ptr/cons/lwg3548.cc: New test.
	* testsuite/20_util/shared_ptr/cons/unique_ptr_deleter.cc: Check
	constraints.

(cherry picked from commit 5edc0c15f1)
2021-05-11 20:50:08 +01:00
Jonathan Wakely
43d3309d98 libstdc++: Fix definition of std::remove_cvref_t
I originally defined std::remove_cvref_t in terms of the internal
__remove_cvref_t trait, to avoid instantiating the remove_cvref class
template. However, as described in P1715R0 that is observable by users
and is thus non-conforming.

This defines remove_cvref_t as specified in the standard.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (remove_cvref_t): Define in terms of
	remove_cvref.
	* testsuite/20_util/remove_cvref/value.cc: Check alias.

(cherry picked from commit 0e79e63026)
2021-05-11 20:50:06 +01:00
Jonathan Wakely
ddfba2359d libstdc++: Reject std::make_shared<T[]> [PR 99006]
Prior to C++20 it should be ill-formed to use std::make_shared with an
array type (and we don't support the C++20 feature to make it valid yet
anyway).

libstdc++-v3/ChangeLog:

	PR libstdc++/99006
	* include/bits/shared_ptr.h (allocate_shared): Assert that _Tp
	is not an array type.
	* include/bits/shared_ptr_base.h (__allocate_shared): Likewise.
	* testsuite/20_util/shared_ptr/creation/99006.cc: New test.

(cherry picked from commit 55650236cd)
2021-05-11 20:50:06 +01:00
Jonathan Wakely
768feed932 libstdc++: Fix constraints for rvalue stream insertion/extraction
The __rval_streamable() function was an attempt to test for
convertibility cheaply and without confusing diagnostics. It doesn't
work with Clang though, and is probably ill-formed.

Replace that helper function with a check for derivation from ios_base,
and use that in the alias templates __rvalue_stream_insertion_t and
__rvalue_stream_extraction_t. Use concepts for the constraints when
available.

libstdc++-v3/ChangeLog:

	* include/std/istream (__rvalue_stream_extraction_t): Replace
	use of __rval_streamable.
	* include/std/ostream (__rvalue_stream_insertion_t): Likewise.
	(__rval_streamable): Remove.
	(_Require_derived_from_ios_base, __derived_from_ios_base): New
	helper for checking constraints.
	* testsuite/27_io/basic_istream/extractors_other/char/4.cc: Fix
	reference to the wrong subclause of the standard.
	* testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_other/char/6.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_other/char/99692.cc:
	New test.
	* testsuite/27_io/filesystem/path/io/dr2989.cc: Adjust pruned
	errors.

(cherry picked from commit a87ceadf17)
2021-05-07 23:50:04 +01:00
Jonathan Wakely
ca7d2f2ec9 libstdc++: Implement LWG 1203 for rvalue iostreams
This implements the resolution of LWG 1203 so that the constraints for
rvalue stream insertion/extraction are simpler, and the return type is
the original rvalue stream type not its base class.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/std/istream (operator>>(Istream&&, x&)): Simplify, as
	per LWG 1203.
	* include/std/ostream (operator<<(Ostream&&, const x&)):
	Likewise.
	* testsuite/27_io/basic_istream/extractors_character/char/lwg2499_neg.cc:
	Adjust dg-error pattern.
	* testsuite/27_io/basic_istream/extractors_character/wchar_t/lwg2499_neg.cc:
	Likewise.
	* testsuite/27_io/basic_istream/extractors_other/char/4.cc: Define
	is_extractable trait to replace std::__is_extractable. Make it
	work with rvalue streams as well as lvalues, to replace f() and
	g() helper functions.
	* testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/inserters_other/char/6.cc:
	Define is_insertable trait to replace std::__is_insertable. Make
	it work with rvalue streams as well as lvalues, to replace f()
	and g() helper functions.
	* testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc:
	Likewise.
	* testsuite/27_io/filesystem/path/io/dr2989.cc: Prune additional
	errors from new constraints.
	* testsuite/27_io/rvalue_streams-2.cc: Remove PR 80675 checks,
	which are no longer expected to compile.
	* testsuite/27_io/rvalue_streams.cc: Adjust existing test.
	Verify LWG 1203 changes.

(cherry picked from commit aa475c4ac8)
2021-05-06 14:05:35 +01:00
Jonathan Wakely
9ff7e01b7f libstdc++: Fix null dereferences in std::promise
This fixes some ubsan errors in std::promise:

future:1153:34: runtime error: member call on null pointer of type 'struct element_type'
future:1153:34: runtime error: member access within null pointer of type 'struct element_type'

The problem is that the check for a null pointer is done inside the
_State::__Setter function, which is only evaluated after evaluating the
_M_future->_M_set_result postfix-expression.

This change adds a new promise::_M_state() helper for accessing
_M_future, and moves the check for no shared state into there, instead
of inside the __setter functions. The __setter functions are made
always_inline, to avoid the situation where the linker selects the old
version of set_value (without the _S_check call) and the new version of
__setter (without the _S_check call) and so there is no check. With the
always_inline attribute the old version of set_value will either inline
the old __setter or call an extern definition of it, and the new
set_value will do the check itself, so both versions do the check.

libstdc++-v3/ChangeLog:

	* include/std/future (promise::set_value): Check for existence
	of shared state before dereferncing it.
	(promise::set_exception, promise::set_value_at_thread_exit)
	(promise::set_exception_at_thread_exit): Likewise.
	(promise<R&>::set_value, promise<R&>::set_exception)
	(promise<R&>::set_value_at_thread_exit)
	(promise<R&>::set_exception_at_thread_exit): Likewise.
	(promise<void>::set_value, promise<void>::set_exception)
	(promise<void>::set_value_at_thread_exit)
	(promise<void>::set_exception_at_thread_exit): Likewise.
	* testsuite/30_threads/promise/members/at_thread_exit2.cc:
	Remove unused variable.

(cherry picked from commit 058d6acefe)
2021-05-06 14:05:35 +01:00
Jonathan Wakely
48a3af6f61 libstdc++: Fix undefined behaviour in std::string
This fixes a ubsan error when constructing a string with a null pointer:

bits/basic_string.h:534:21: runtime error: applying non-zero offset 18446744073709551615 to null pointer

The _M_construct function only cares whether the second pointer is
non-null, so create a non-null value without undefined arithmetic.

We can also pass the random_access_iterator_tag directly to the
_M_construct function, to avoid going via the tag dispatching
_M_construct_aux, because we know we have pointers not integers here.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (basic_string(const CharT*, const A&)):
	Do not do arithmetic on null pointer.

(cherry picked from commit 789c57bc5f)
2021-05-06 14:05:35 +01:00
Jonathan Wakely
00ddf72a6f libstdc++: Fix null dereference in pb_ds containers
This fixes ubsan errors:

ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp:533:15: runtime error: member access within null pointer of type 'struct entry'

libstdc++-v3/ChangeLog:

	* include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp
	(find_key_pointer(key_const_reference, false_type))
	(find_key_pointer(key_const_reference, true_type)): Do not
	dereference null pointer.

(cherry picked from commit ca871701c2)
2021-05-06 14:05:34 +01:00
Jonathan Wakely
e99763ee6d libstdc++: Do not use deduced return type for std::visit [PR 100384]
This avoids errors outside the immediate context when std::visit is an
overload candidate because of ADL, but not actually viable.

The solution is to give std::visit a non-deduced return type. New
helpers are introduced for that, and existing ones refactored slightly.

libstdc++-v3/ChangeLog:

	PR libstdc++/100384
	* include/std/variant (__get_t): New alias template yielding the
	return type of std::get<N> on a variant.
	(__visit_result_t): New alias template yielding the result of
	std::visit.
	(__same_types): Move into namespace __detail::__variant.
	(__check_visitor_results): Likewise. Use __invoke_result_t and
	__get_t.
	(__check_visitor_result): Remove.
	(visit): Use __visit_result_t for return type.
	* testsuite/20_util/variant/100384.cc: New test.

(cherry picked from commit af5b2b911d)
2021-05-06 14:05:34 +01:00