Commit Graph

12963 Commits

Author SHA1 Message Date
Jonathan Wakely
5ea8803e65 libstdc++: Use std::construct_at in net::ip::address
Using placement-new isn't valid in constant expressions, so this
replaces it with std::construct_at (via the std::_Construct function
that is usable before C++20).

libstdc++-v3/ChangeLog:

	* include/experimental/internet (address): Use std::_Construct
	to initialize union members.
2021-11-17 17:28:52 +00:00
Jonathan Wakely
5a9572e486 libstdc++: Simplify std::string constructors
Several std::basic_string constructors dispatch to one of the
two-argument overloads of _M_construct, which then dispatches again to
_M_construct_aux to detect whether the arguments are iterators or not.
That then dispatches to one of _M_construct(size_type, char_type) or
_M_construct(Iter, Iter, iterator_traits<Iter>::iterator_category{}).

For most of those constructors this is a waste of time, because we know
the arguments are already iterators. For basic_string(const CharT*) and
basic_string(initializer_list<C>) we know that we call _M_construct with
two pointers, and for basic_string(const basic_string&) we call it with
two const_iterators.  Those constructors can call the three-argument
overload of _M_construct with the iterator category tag right away,
without the intermediate dispatching.

The case where this doesn't apply is basic_string(InputIter, InputIter),
but for C++11 and later this is constrained so we know it's an iterator
here as well. We can restrict the dispatching in this constructor to
only be done for C++98 and to call _M_construct_aux directly, which
allows us to remove the two-argument _M_construct(InputIter, InputIter)
overload entirely.

N.B. When calling the three-arg _M_construct with pointers or string
iterators, we pass forward_iterator_tag not random_access_iterator_tag.
This is because it makes no difference which overload gets called, and
simplifies overload resolution to not have to do a base-to-derived
check. If we ever add a new overload of M_construct for random access
iterators we would have to revisit this, but that seems unlikely.

This patch also moves the __is_null_pointer checks from the three-arg
_M_construct into the constructors where a null pointer argument is
actually possible. This avoids redundant checks where we know we have a
non-null pointer, or don't have a pointer at all.

Finally, this patch replaces some try-blocks with an RAII type, so that
memory is deallocated during unwinding. This avoids the overhead of
catching and rethrowing an exception.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (_M_construct_aux): Only define
	for C++98. Remove constexpr.
	(_M_construct_aux_2): Likewise.
	(_M_construct(InputIter, InputIter)): Remove.
	(basic_string(const basic_string&)): Call _M_construct with
	iterator category argument.
	(basic_string(const basic_string&, size_type, const Alloc&)):
	Likewise.
	(basic_string(const basic_string&, size_type, size_type)):
	Likewise.
	(basic_string(const charT*, size_type, const Alloc&)): Likewise.
	Check for null pointer.
	(basic_string(const charT*, const Alloc&)): Likewise.
	(basic_string(initializer_list<charT>, const Alloc&)): Call
	_M_construct with iterator category argument.
	(basic_string(const basic_string&, const Alloc&)): Likewise.
	(basic_string(basic_string&&, const Alloc&)): Likewise.
	(basic_string(_InputIter, _InputIter, const Alloc&)): Likewise
	for C++11 and later, call _M_construct_aux for C++98.
	* include/bits/basic_string.tcc
	(_M_construct(I, I, input_iterator_tag)): Replace try-block with
	RAII type.
	(_M_construct(I, I, forward_iterator_tag)): Likewise. Remove
	__is_null_pointer check.
2021-11-17 17:28:44 +00:00
Jonathan Wakely
6afa1083c6 libstdc++: Set active member of union in std::string [PR103295]
Clang diagnoses that the new constexpr std::string constructors are not
usable in constant expressions, because they start to write to members
of the union without setting an active member.

This adds a new helper function which returns the address of the local
buffer after making it the active member.

This doesn't fix all problems with Clang, because it still refuses to
write to memory returned by the allocator.

libstdc++-v3/ChangeLog:

	PR libstdc++/103295
	* include/bits/basic_string.h (_M_use_local_data()): New
	member function to make local buffer the active member.
	(assign(const basic_string&)): Use it.
	* include/bits/basic_string.tcc (_M_construct, reserve()):
	Likewise.
2021-11-17 17:21:25 +00:00
Jonathan Wakely
054bf99841 libstdc++: Fix std::type_info::before for ARM [PR103240]
The r179236 fix for std::type_info::operator== should also have been
applied to std::type_info::before. Otherwise two distinct types can
compare equivalent due to using a string comparison, when they should do
a pointer comparison.

libstdc++-v3/ChangeLog:

	PR libstdc++/103240
	* libsupc++/tinfo2.cc (type_info::before): Use unadjusted name
	to check for the '*' prefix.
	* testsuite/util/testsuite_shared.cc: Add type_info object for
	use in new test.
	* testsuite/18_support/type_info/103240.cc: New test.
2021-11-17 17:21:24 +00:00
GCC Administrator
6b1695f4a0 Daily bump. 2021-11-17 00:16:29 +00:00
Jonathan Wakely
73e4d9f175 libstdc++: Fix tests for constexpr std::string
Some tests fail when run with -D_GLIBCXX_USE_CXX11_ABI or -stdgnu++20.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (operator<=>): Use constexpr
	unconditionally.
	* testsuite/21_strings/basic_string/modifiers/constexpr.cc:
	Require cxx11-abit effective target.
	* testsuite/21_strings/headers/string/synopsis.cc: Add
	conditional constexpr to declarations, and adjust relational
	operators for C++20.
2021-11-16 22:48:15 +00:00
Patrick Palka
7461b58131 libstdc++: Merge latest Ryu sources
libstdc++-v3/ChangeLog:

	* src/c++17/ryu/MERGE: Update the commit hash.
	* src/c++17/ryu/d2s_intrinsics.h: Merge from Ryu's master
	branch.

Signed-off-by: Patrick Palka <ppalka@redhat.com>
2021-11-16 12:23:27 -05:00
Michael de Lang
b96e2ff9d8 libstdc++: Implement constexpr std::basic_string for C++20
This is only supported for the cxx11 ABI, not for COW strings.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (basic_string, operator""s): Add
	constexpr for C++20.
	(basic_string::basic_string(basic_string&&)): Only copy
	initialized portion of the buffer.
	(basic_string::basic_string(basic_string&&, const Alloc&)):
	Likewise.
	* include/bits/basic_string.tcc (basic_string): Add constexpr
	for C++20.
	(basic_string::swap(basic_string&)): Only copy initialized
	portions of the buffers.
	(basic_string::_M_replace): Add constexpr implementation that
	doesn't depend on pointer comparisons.
	* include/bits/cow_string.h: Adjust comment.
	* include/ext/type_traits.h (__is_null_pointer): Add constexpr.
	* include/std/string (erase, erase_if): Add constexpr.
	* include/std/version (__cpp_lib_constexpr_string): Update
	value.
	* testsuite/21_strings/basic_string/cons/char/constexpr.cc:
	New test.
	* testsuite/21_strings/basic_string/cons/wchar_t/constexpr.cc:
	New test.
	* testsuite/21_strings/basic_string/literals/constexpr.cc:
	New test.
	* testsuite/21_strings/basic_string/modifiers/constexpr.cc: New test.
	* testsuite/21_strings/basic_string/modifiers/swap/char/constexpr.cc:
	New test.
	* testsuite/21_strings/basic_string/modifiers/swap/wchar_t/constexpr.cc:
	New test.
	* testsuite/21_strings/basic_string/version.cc: New test.
2021-11-16 16:43:20 +00:00
Jonathan Wakely
59434931fb libstdc++: Use hidden friends for vector<bool>::reference swap overloads
These swap overloads are non-standard, but are needed to make swap work
for vector<bool>::reference rvalues. They don't need to be called
explicitly, only via ADL, so hide them from normal lookup. This is what
I've proposed as the resolution to LWG 3638.

libstdc++-v3/ChangeLog:

	* include/bits/stl_bvector.h (swap(_Bit_reference, _Bit_reference))
	(swap(_Bit_reference, bool&), swap(bool&, _Bit_reference)):
	Define as hidden friends of _Bit_reference.
2021-11-16 16:42:59 +00:00
Jonathan Wakely
8d8e8f3ad5 libstdc++: Fix out-of-bound array accesses in testsuite
I fixed some undefined behaviour in string tests in r238609, but I only
fixed the narrow char versions. This applies the same fixes to the
wchar_t ones. These problems were found when testing a patch to make
std::basic_string usable in constexpr.

libstdc++-v3/ChangeLog:

	* testsuite/21_strings/basic_string/modifiers/append/wchar_t/1.cc:
	Fix reads past the end of strings.
	* testsuite/21_strings/basic_string/operations/compare/wchar_t/1.cc:
	Likewise.
	* testsuite/experimental/string_view/operations/compare/wchar_t/1.cc:
	Likewise.
2021-11-16 14:09:00 +00:00
Jonathan Wakely
9719769471 libstdc++: Fix typos in tests
libstdc++-v3/ChangeLog:

	* testsuite/21_strings/basic_string/allocator/71964.cc: Fix
	typo.
	* testsuite/23_containers/set/allocator/71964.cc: Likewise.
2021-11-16 14:08:42 +00:00
GCC Administrator
e2b57363fc Daily bump. 2021-11-16 00:16:31 +00:00
Jason Merrill
87c2080b05 c++: Add -fimplicit-constexpr
With each successive C++ standard the restrictions on the use of the
constexpr keyword for functions get weaker and weaker; it recently occurred
to me that it is heading toward the same fate as the C register keyword,
which was once useful for optimization but became obsolete.  Similarly, it
seems to me that we should be able to just treat inlines as constexpr
functions and not make people add the extra keyword everywhere.

There were a lot of testcase changes needed; many disabling errors about
non-constexpr functions that are now constexpr, and many disabling implicit
constexpr so that the tests can check the same thing as before, whether
that's mangling or whatever.

gcc/c-family/ChangeLog:

	* c.opt: Add -fimplicit-constexpr.
	* c-cppbuiltin.c: Define __cpp_implicit_constexpr.
	* c-opts.c (c_common_post_options): Disable below C++14.

gcc/cp/ChangeLog:

	* cp-tree.h (struct lang_decl_fn): Add implicit_constexpr.
	(decl_implicit_constexpr_p): New.
	* class.c (type_maybe_constexpr_destructor): Use
	TYPE_HAS_TRIVIAL_DESTRUCTOR and maybe_constexpr_fn.
	(finalize_literal_type_property): Simplify.
	* constexpr.c (is_valid_constexpr_fn): Check for dtor.
	(maybe_save_constexpr_fundef): Try to set DECL_DECLARED_CONSTEXPR_P
	on inlines.
	(cxx_eval_call_expression): Use maybe_constexpr_fn.
	(maybe_constexpr_fn): Handle flag_implicit_constexpr.
	(var_in_maybe_constexpr_fn): Use maybe_constexpr_fn.
	(potential_constant_expression_1): Likewise.
	(decl_implicit_constexpr_p): New.
	* decl.c (validate_constexpr_redeclaration): Allow change with
	-fimplicit-constexpr.
	(grok_special_member_properties): Use maybe_constexpr_fn.
	* error.c (dump_function_decl): Don't print 'constexpr'
	if it's implicit.
	* Make-lang.in (check-c++-all): Update.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/to_address/1_neg.cc: Adjust error.
	* testsuite/26_numerics/random/concept.cc: Adjust asserts.

gcc/testsuite/ChangeLog:

	* lib/g++-dg.exp: Handle "impcx".
	* lib/target-supports.exp
	(check_effective_target_implicit_constexpr): New.
	* g++.dg/abi/abi-tag16.C:
	* g++.dg/abi/abi-tag18a.C:
	* g++.dg/abi/guard4.C:
	* g++.dg/abi/lambda-defarg1.C:
	* g++.dg/abi/mangle26.C:
	* g++.dg/cpp0x/constexpr-diag3.C:
	* g++.dg/cpp0x/constexpr-ex1.C:
	* g++.dg/cpp0x/constexpr-ice5.C:
	* g++.dg/cpp0x/constexpr-incomplete2.C:
	* g++.dg/cpp0x/constexpr-memfn1.C:
	* g++.dg/cpp0x/constexpr-neg3.C:
	* g++.dg/cpp0x/constexpr-specialization.C:
	* g++.dg/cpp0x/inh-ctor19.C:
	* g++.dg/cpp0x/inh-ctor30.C:
	* g++.dg/cpp0x/lambda/lambda-mangle3.C:
	* g++.dg/cpp0x/lambda/lambda-mangle5.C:
	* g++.dg/cpp1y/auto-fn12.C:
	* g++.dg/cpp1y/constexpr-loop5.C:
	* g++.dg/cpp1z/constexpr-lambda7.C:
	* g++.dg/cpp2a/constexpr-dtor3.C:
	* g++.dg/cpp2a/constexpr-new13.C:
	* g++.dg/cpp2a/constinit11.C:
	* g++.dg/cpp2a/constinit12.C:
	* g++.dg/cpp2a/constinit14.C:
	* g++.dg/cpp2a/constinit15.C:
	* g++.dg/cpp2a/spaceship-constexpr1.C:
	* g++.dg/cpp2a/spaceship-eq3.C:
	* g++.dg/cpp2a/udlit-class-nttp-neg2.C:
	* g++.dg/debug/dwarf2/auto1.C:
	* g++.dg/debug/dwarf2/cdtor-1.C:
	* g++.dg/debug/dwarf2/lambda1.C:
	* g++.dg/debug/dwarf2/pr54508.C:
	* g++.dg/debug/dwarf2/pubnames-2.C:
	* g++.dg/debug/dwarf2/pubnames-3.C:
	* g++.dg/ext/is_literal_type3.C:
	* g++.dg/ext/visibility/template7.C:
	* g++.dg/gcov/gcov-12.C:
	* g++.dg/gcov/gcov-2.C:
	* g++.dg/ipa/devirt-35.C:
	* g++.dg/ipa/devirt-36.C:
	* g++.dg/ipa/devirt-37.C:
	* g++.dg/ipa/devirt-44.C:
	* g++.dg/ipa/imm-devirt-1.C:
	* g++.dg/lookup/builtin5.C:
	* g++.dg/lto/inline-crossmodule-1_0.C:
	* g++.dg/modules/enum-1_a.C:
	* g++.dg/modules/fn-inline-1_c.C:
	* g++.dg/modules/pmf-1_b.C:
	* g++.dg/modules/used-1_c.C:
	* g++.dg/tls/thread_local11.C:
	* g++.dg/tls/thread_local11a.C:
	* g++.dg/tm/pr46653.C:
	* g++.dg/ubsan/pr70035.C:
	* g++.old-deja/g++.other/delete6.C:
	* g++.dg/modules/pmf-1_a.H:
	Adjust for implicit constexpr.
2021-11-15 18:50:07 -05:00
François Dumont
d10b863fa3 libstdc++: Unordered containers merge re-use hash code
When merging 2 unordered containers with same hasher we can re-use the hash code from
the cache if any.

Also in the context of the merge operation on multi-container use previous insert iterator as a hint
for the next insert.

libstdc++-v3/ChangeLog:

	* include/bits/hashtable_policy.h:
	(_Hash_code_base<>::_M_hash_code(const _Hash&, const _Hash_node_value<_Value, true>&)): New.
	(_Hash_code_base<>::_M_hash_code<_H2>(const _H2&, const _Hash_node_value<>&)): New.
	* include/bits/hashtable.h (_Hashtable<>::_M_merge_unique): Use latter.
	(_Hashtable<>::_M_merge_multi): Likewise.
	* testsuite/23_containers/unordered_multiset/modifiers/merge.cc (test05): New test.
	* testsuite/23_containers/unordered_set/modifiers/merge.cc (test04): New test.
2021-11-15 18:52:07 +01:00
Jason Merrill
37326651b4 c++: check constexpr constructor body
The implicit constexpr patch revealed that our checks for constexpr
constructors that could possibly produce a constant value (which
otherwise are IFNDR) was failing to look at most of the function body.
Fixing that required some library tweaks.

gcc/cp/ChangeLog:

	* constexpr.c (maybe_save_constexpr_fundef): Also check whether the
	body of a constructor is potentially constant.

libstdc++-v3/ChangeLog:

	* src/c++17/memory_resource.cc: Add missing constexpr.
	* include/experimental/internet: Only mark copy constructor
	as constexpr with __cpp_constexpr_dynamic_alloc.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/constexpr-89285-2.C: Expect error.
	* g++.dg/cpp1y/constexpr-89285.C: Adjust error.
2021-11-15 02:50:45 -05:00
GCC Administrator
b85a03ae11 Daily bump. 2021-11-15 00:16:20 +00:00
François Dumont
e9a53a4f76 libstdc++: [_GLIBCXX_DEBUG] Remove _Safe_container<>::_M_safe()
_GLIBCXX_DEBUG container code cleanup to get rid of _Safe_container<>::_M_safe() and just
use _Safe:: calls which use normal inheritance. Also remove several usages of _M_base()
which can be most of the time ommitted and sometimes replace with explicit _Base::
calls.

libstdc++-v3/ChangeLog:

	* include/debug/safe_container.h (_Safe_container<>::_M_safe): Remove.
	* include/debug/deque (deque::operator=(initializer_list<>)): Replace
	_M_base() call with _Base:: call.
	(deque::operator[](size_type)): Likewise.
	* include/debug/forward_list (forward_list(forward_list&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(forward_list::operator=(initializer_list<>)): Remove _M_base() calls.
	(forward_list::splice_after, forward_list::merge): Likewise.
	* include/debug/list (list(list&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(list::operator=(initializer_list<>)): Remove _M_base() calls.
	(list::splice, list::merge): Likewise.
	* include/debug/map.h (map(map&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(map::operator=(initializer_list<>)): Remove _M_base() calls.
	* include/debug/multimap.h (multimap(multimap&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(multimap::operator=(initializer_list<>)): Remove _M_base() calls.
	* include/debug/set.h (set(set&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(set::operator=(initializer_list<>)): Remove _M_base() calls.
	* include/debug/multiset.h (multiset(multiset&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(multiset::operator=(initializer_list<>)): Remove _M_base() calls.
	* include/debug/string (basic_string(basic_string&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(basic_string::operator=(initializer_list<>)): Remove _M_base() call.
	(basic_string::operator=(const _CharT*), basic_string::operator=(_CharT)): Likewise.
	(basic_string::operator[](size_type), basic_string::operator+=(const basic_string&)):
	Likewise.
	(basic_string::operator+=(const _Char*), basic_string::operator+=(_CharT)): Likewise.
	* include/debug/unordered_map (unordered_map(unordered_map&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(unordered_map::operator=(initializer_list<>), unordered_map::merge):
	Remove _M_base() calls.
	(unordered_multimap(unordered_multimap&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(unordered_multimap::operator=(initializer_list<>), unordered_multimap::merge):
	Remove _M_base() calls.
	* include/debug/unordered_set (unordered_set(unordered_set&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(unordered_set::operator=(initializer_list<>), unordered_set::merge):
	Remove _M_base() calls.
	(unordered_multiset(unordered_multiset&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(unordered_multiset::operator=(initializer_list<>), unordered_multiset::merge):
	Remove _M_base() calls.
	* include/debug/vector (vector(vector&&, const allocator_type&)):
	Remove _M_safe() and _M_base() calls.
	(vector::operator=(initializer_list<>)): Remove _M_base() calls.
	(vector::operator[](size_type)): Likewise.
2021-11-14 21:55:01 +01:00
GCC Administrator
a8029add30 Daily bump. 2021-11-14 00:16:23 +00:00
Jonathan Wakely
a30a2e43e4 libstdc++: Implement std::spanstream for C++23
This implements the <spanstream> header, as proposed for C++23 by P0448R4.

libstdc++-v3/ChangeLog:

	* include/Makefile.am: Add spanstream header.
	* include/Makefile.in: Regenerate.
	* include/precompiled/stdc++.h: Add spanstream header.
	* include/std/version (__cpp_lib_spanstream): Define.
	* include/std/spanstream: New file.
	* testsuite/27_io/spanstream/1.cc: New test.
	* testsuite/27_io/spanstream/version.cc: New test.
2021-11-13 11:45:31 +00:00
Hans-Peter Nilsson
60f761c7e5 libstdc++: Use GCC_TRY_COMPILE_OR_LINK for getentropy, arc4random
Since r12-5056-g3439657b0286, there has been a regression in
test results; an additional 100 FAILs running the g++ and
libstdc++ testsuite on cris-elf, a newlib target.  The
failures are linker errors, not finding a definition for
getentropy.  It appears newlib has since 2017-12-03
declarations of getentropy and arc4random, and provides an
implementation of arc4random using getentropy, but provides no
definition of getentropy, not even a stub yielding ENOSYS.
This is similar to what it does for many other functions too.

While fixing newlib (like adding said stub) would likely help,
it still leaves older newlib releases hanging.  Thankfully,
the libstdc++ configury test can be improved to try linking
where possible; using the bespoke GCC_TRY_COMPILE_OR_LINK
instead of AC_TRY_COMPILE.  BTW, I see a lack of consistency;
some tests use AC_TRY_COMPILE and some GCC_TRY_COMPILE_OR_LINK
for no apparent reason, but this commit just amends
r12-5056-g3439657b0286.

libstdc++-v3:
	PR libstdc++/103166
	* acinclude.m4 (GLIBCXX_CHECK_GETENTROPY, GLIBCXX_CHECK_ARC4RANDOM):
	Use GCC_TRY_COMPILE_OR_LINK instead of AC_TRY_COMPILE.
	* configure: Regenerate.
2021-11-13 01:45:06 +01:00
GCC Administrator
af2852b9dc Daily bump. 2021-11-13 00:16:39 +00:00
Jonathan Wakely
a54ce8865a libstdc++: Print assertion messages to stderr [PR59675]
This replaces the printf used by failed debug assertions with fprintf,
so we can write to stderr.

To avoid including <stdio.h> the assert function is moved into the
library. To avoid programs using a vague linkage definition of the old
inline function, the function is renamed. Code compiled with old
versions of GCC might still call the old function, but code compiled
with the newer GCC will call the new function and write to stderr.

libstdc++-v3/ChangeLog:

	PR libstdc++/59675
	* acinclude.m4 (libtool_VERSION): Bump version.
	* config/abi/pre/gnu.ver (GLIBCXX_3.4.30): Add version and
	export new symbol.
	* configure: Regenerate.
	* include/bits/c++config (__replacement_assert): Remove, declare
	__glibcxx_assert_fail instead.
	* src/c++11/debug.cc (__glibcxx_assert_fail): New function to
	replace __replacement_assert, writing to stderr instead of
	stdout.
	* testsuite/util/testsuite_abi.cc: Update latest version.
2021-11-12 12:23:10 +00:00
Jonathan Wakely
1ae8edf5f7 libstdc++: Implement constexpr std::vector for C++20
This implements P1004R2 ("Making std::vector constexpr") for C++20.

For now, debug mode vectors are not supported in constant expressions.
To make that work we might need to disable all attaching/detaching of
safe iterators. That can be fixed later.

Co-authored-by: Josh Marshall <joshua.r.marshall.1991@gmail.com>

libstdc++-v3/ChangeLog:

	* include/bits/alloc_traits.h (_Destroy): Make constexpr for
	C++20 mode.
	* include/bits/allocator.h (__shrink_to_fit::_S_do_it):
	Likewise.
	* include/bits/stl_algobase.h (__fill_a1): Declare _Bit_iterator
	overload constexpr for C++20.
	* include/bits/stl_bvector.h (_Bit_type, _S_word_bit): Move out
	of inline namespace.
	(_Bit_reference, _Bit_iterator_base, _Bit_iterator)
	(_Bit_const_iterator, _Bvector_impl_data, _Bvector_base)
	(vector<bool, A>>): Add constexpr to every member function.
	(_Bvector_base::_M_allocate): Initialize storage during constant
	evaluation.
	(vector<bool, A>::_M_initialize_value): Use __fill_bvector_n
	instead of memset.
	(__fill_bvector_n): New helper function to replace memset during
	constant evaluation.
	* include/bits/stl_uninitialized.h (__uninitialized_copy<false>):
	Move logic to ...
	(__do_uninit_copy): New function.
	(__uninitialized_fill<false>): Move logic to ...
	(__do_uninit_fill): New function.
	(__uninitialized_fill_n<false>): Move logic to ...
	(__do_uninit_fill_n): New function.
	(__uninitialized_copy_a): Add constexpr. Use __do_uninit_copy.
	(__uninitialized_move_a, __uninitialized_move_if_noexcept_a):
	Add constexpr.
	(__uninitialized_fill_a): Add constexpr. Use __do_uninit_fill.
	(__uninitialized_fill_n_a): Add constexpr. Use
	__do_uninit_fill_n.
	(__uninitialized_default_n, __uninitialized_default_n_a)
	(__relocate_a_1, __relocate_a): Add constexpr.
	* include/bits/stl_vector.h (_Vector_impl_data, _Vector_impl)
	(_Vector_base, vector): Add constexpr to every member function.
	(_Vector_impl::_S_adjust): Disable ASan annotation during
	constant evaluation.
	(_Vector_base::_S_use_relocate): Disable bitwise-relocation
	during constant evaluation.
	(vector::_Temporary_value): Use a union for storage.
	* include/bits/vector.tcc (vector, vector<bool>): Add constexpr
	to every member function.
	* include/std/vector (erase_if, erase): Add constexpr.
	* testsuite/23_containers/headers/vector/synopsis.cc: Add
	constexpr for C++20 mode.
	* testsuite/23_containers/vector/bool/cmp_c++20.cc: Change to
	compile-only test using constant expressions.
	* testsuite/23_containers/vector/bool/capacity/29134.cc: Adjust
	namespace for _S_word_bit.
	* testsuite/23_containers/vector/bool/modifiers/insert/31370.cc:
	Likewise.
	* testsuite/23_containers/vector/cmp_c++20.cc: Likewise.
	* testsuite/23_containers/vector/cons/89164.cc: Adjust errors
	for C++20 and move C++17 test to ...
	* testsuite/23_containers/vector/cons/89164_c++17.cc: ... here.
	* testsuite/23_containers/vector/bool/capacity/constexpr.cc: New test.
	* testsuite/23_containers/vector/bool/cons/constexpr.cc: New test.
	* testsuite/23_containers/vector/bool/element_access/constexpr.cc: New test.
	* testsuite/23_containers/vector/bool/modifiers/assign/constexpr.cc: New test.
	* testsuite/23_containers/vector/bool/modifiers/constexpr.cc: New test.
	* testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc: New test.
	* testsuite/23_containers/vector/capacity/constexpr.cc: New test.
	* testsuite/23_containers/vector/cons/constexpr.cc: New test.
	* testsuite/23_containers/vector/data_access/constexpr.cc: New test.
	* testsuite/23_containers/vector/element_access/constexpr.cc: New test.
	* testsuite/23_containers/vector/modifiers/assign/constexpr.cc: New test.
	* testsuite/23_containers/vector/modifiers/constexpr.cc: New test.
	* testsuite/23_containers/vector/modifiers/swap/constexpr.cc: New test.
2021-11-12 00:42:39 +00:00
GCC Administrator
b39265d4fe Daily bump. 2021-11-12 00:16:32 +00:00
Jonathan Wakely
4a407d358e libstdc++: Fix debug containers for C++98 mode
Since r12-5072 made _Safe_container::operator=(const _Safe_container&)
protected, the debug containers no longer compile in C++98 mode. They
have user-provided copy assignment operators in C++98 mode, and they
assign each base class in turn. The 'this->_M_safe() = __x' expressions
fail, because calling a protected member function is only allowed via
'this'. They could be fixed by using this->_Safe::operator=(__x) but a
simpler solution is to just remove the user-provided assignment
operators and let the compiler define them (as we do for C++11 and
later, by defining them as defaulted).

The only change needed for that to work is to define the _Safe_vector
copy assignment operator in C++98 mode, so that the implicit
__gnu_debug::vector::operator= definition will call it, instead of
needing to call _M_update_guaranteed_capacity() manually.

libstdc++-v3/ChangeLog:

	* include/debug/deque (deque::operator=(const deque&)): Remove
	definition.
	* include/debug/list (list::operator=(const list&)): Likewise.
	* include/debug/map.h (map::operator=(const map&)): Likewise.
	* include/debug/multimap.h (multimap::operator=(const multimap&)):
	Likewise.
	* include/debug/multiset.h (multiset::operator=(const multiset&)):
	Likewise.
	* include/debug/set.h (set::operator=(const set&)): Likewise.
	* include/debug/string (basic_string::operator=(const basic_string&)):
	Likewise.
	* include/debug/vector (vector::operator=(const vector&)):
	Likewise.
	(_Safe_vector::operator=(const _Safe_vector&)): Define for
	C++98 as well.
2021-11-11 21:55:11 +00:00
Jonathan Wakely
083fd73202 libstdc++: Make pmr::memory_resource::allocate implicitly create objects
Calling the placement version of ::operator new "implicitly creates
objects in the returned region of storage" as per [intro.object]. This
allows the returned memory to be used as storage for implicit-lifetime
types (including arrays) without additional action by the caller. This
is required by the proposed resolution of LWG 3147.

libstdc++-v3/ChangeLog:

	* include/std/memory_resource (memory_resource::allocate):
	Implicitly create objects in the returned storage.
2021-11-11 18:16:17 +00:00
Jonathan Wakely
ef0e100f58 libstdc++: Remove public std::vector<bool>::data() member
This function only exists to avoid an error in the debug mode vector, so
doesn't need to be public.

libstdc++-v3/ChangeLog:

	* include/bits/stl_bvector.h (vector<bool>::data()): Give
	protected access, and delete for C++11 and later.
2021-11-11 18:16:17 +00:00
GCC Administrator
8d36a0d288 Daily bump. 2021-11-11 00:16:28 +00:00
Jonathan Wakely
77963796ae libstdc++: Fix test for libstdc++ not including <unistd.h> [PR100117]
The <cxxx> headers for the C library are not under our control, so we
can't prevent them from including <unistd.h>. Change the PR 49745 test
to only include the C++ library headers, not the <cxxx> ones.

To ensure <bits/stdc++.h> isn't included automatically we need to use
no_pch to disable PCH.

libstdc++-v3/ChangeLog:

	PR libstdc++/100117
	* testsuite/17_intro/headers/c++1998/49745.cc: Explicitly list
	all C++ headers instead of including <bits/stdc++.h>
2021-11-10 12:03:29 +00:00
Jonathan Wakely
80fe172ba9 libstdc++: Disable gthreads weak symbols for glibc 2.34 [PR103133]
Since Glibc 2.34 all pthreads symbols are defined directly in libc not
libpthread, and since Glibc 2.32 we have used __libc_single_threaded to
avoid unnecessary locking in single-threaded programs. This means there
is no reason to avoid linking to libpthread now, and so no reason to use
weak symbols defined in gthr-posix.h for all the pthread_xxx functions.

libstdc++-v3/ChangeLog:

	PR libstdc++/100748
	PR libstdc++/103133
	* config/os/gnu-linux/os_defines.h (_GLIBCXX_GTHREAD_USE_WEAK):
	Define for glibc 2.34 and later.
2021-11-10 12:01:27 +00:00
GCC Administrator
c9b1334eec Daily bump. 2021-11-10 00:16:28 +00:00
François Dumont
f4b4ce152a libstdc++: [_GLIBCXX_DEBUG] Implement unordered container merge
The _GLIBCXX_DEBUG unordered containers need a dedicated merge implementation
so that any existing iterator on the transfered nodes is properly invalidated.

Add typedef/using declarations for everything used as-is from normal implementation.

libstdc++-v3/ChangeLog:

	* include/bits/hashtable_policy.h (__distance_fw): Replace class keyword with
	typename.
	* include/bits/hashtable.h (_Hashtable<>::_M_merge_unique): Remove noexcept
	qualification. Use const_iterator for node extraction/reinsert.
	(_Hashtable<>::_M_merge_multi): Likewise. Compute new hash code before extract.
	* include/debug/safe_container.h (_Safe_container<>): Make all methods
	protected.
	* include/debug/safe_unordered_container.h
	(_Safe_unordered_container<>::_UContInvalidatePred<_ExtractKey, _Source>): New.
	(_Safe_unordered_container<>::_UMContInvalidatePred<_ExtractKey, _Source>): New.
	(_Safe_unordered_container<>::_UContMergeGuard<_Source, _InvalidatePred>): New.
	(_Safe_unordered_container<>::_S_uc_guard<_ExtractKey, _Source>): New.
	(_Safe_unordered_container<>::_S_umc_guard<_ExtractKey, _Source>): New.
	(_Safe_unordered_container<>::_M_invalide_all): Make public.
	(_Safe_unordered_container<>::_M_invalide_if): Likewise.
	(_Safe_unordered_container<>::_M_invalide_local_if): Likewise.
	* include/debug/unordered_map
	(unordered_map<>::mapped_type, pointer, const_pointer): New typedef.
	(unordered_map<>::reference, const_reference, difference_type): New typedef.
	(unordered_map<>::get_allocator, empty, size, max_size): Add usings.
	(unordered_map<>::bucket_count, max_bucket_count, bucket): Add usings.
	(unordered_map<>::hash_function, key_equal, count, contains): Add usings.
	(unordered_map<>::operator[], at, rehash, reserve): Add usings.
	(unordered_map<>::merge): New.
	(unordered_multimap<>::mapped_type, pointer, const_pointer): New typedef.
	(unordered_multimap<>::reference, const_reference, difference_type): New typedef.
	(unordered_multimap<>::get_allocator, empty, size, max_size): Add usings.
	(unordered_multimap<>::bucket_count, max_bucket_count, bucket): Add usings.
	(unordered_multimap<>::hash_function, key_equal, count, contains): Add usings.
	(unordered_multimap<>::rehash, reserve): Add usings.
	(unordered_multimap<>::merge): New.
	* include/debug/unordered_set
	(unordered_set<>::mapped_type, pointer, const_pointer): New typedef.
	(unordered_set<>::reference, const_reference, difference_type): New typedef.
	(unordered_set<>::get_allocator, empty, size, max_size): Add usings.
	(unordered_set<>::bucket_count, max_bucket_count, bucket): Add usings.
	(unordered_set<>::hash_function, key_equal, count, contains): Add usings.
	(unordered_set<>::rehash, reserve): Add usings.
	(unordered_set<>::merge): New.
	(unordered_multiset<>::mapped_type, pointer, const_pointer): New typedef.
	(unordered_multiset<>::reference, const_reference, difference_type): New typedef.
	(unordered_multiset<>::get_allocator, empty, size, max_size): Add usings.
	(unordered_multiset<>::bucket_count, max_bucket_count, bucket): Add usings.
	(unordered_multiset<>::hash_function, key_equal, count, contains): Add usings.
	(unordered_multiset<>::rehash, reserve): Add usings.
	(unordered_multiset<>::merge): New.
	* testsuite/23_containers/unordered_map/debug/merge1_neg.cc: New test.
	* testsuite/23_containers/unordered_map/debug/merge2_neg.cc: New test.
	* testsuite/23_containers/unordered_map/debug/merge3_neg.cc: New test.
	* testsuite/23_containers/unordered_map/debug/merge4_neg.cc: New test.
	* testsuite/23_containers/unordered_multimap/debug/merge1_neg.cc: New test.
	* testsuite/23_containers/unordered_multimap/debug/merge2_neg.cc: New test.
	* testsuite/23_containers/unordered_multimap/debug/merge3_neg.cc: New test.
	* testsuite/23_containers/unordered_multimap/debug/merge4_neg.cc: New test.
	* testsuite/23_containers/unordered_multiset/debug/merge1_neg.cc: New test.
	* testsuite/23_containers/unordered_multiset/debug/merge2_neg.cc: New test.
	* testsuite/23_containers/unordered_multiset/debug/merge3_neg.cc: New test.
	* testsuite/23_containers/unordered_multiset/debug/merge4_neg.cc: New test.
	* testsuite/23_containers/unordered_set/debug/merge1_neg.cc: New test.
	* testsuite/23_containers/unordered_set/debug/merge2_neg.cc: New test.
	* testsuite/23_containers/unordered_set/debug/merge3_neg.cc: New test.
	* testsuite/23_containers/unordered_set/debug/merge4_neg.cc: New test.
	* testsuite/util/testsuite_abi.h: [_GLIBCXX_DEBUG] Use normal unordered
	container implementation.
2021-11-09 21:50:17 +01:00
Jonathan Wakely
95e8fcd3d5 libstdc++: Make test print which random_device tokens work
libstdc++-v3/ChangeLog:

	* testsuite/26_numerics/random/random_device/cons/token.cc:
	Print results of random_device_available checks.
2021-11-09 15:12:29 +00:00
Jonathan Wakely
d9ebf0ce08 libstdc++: Do not use 64-bit DARN on 32-bit powerpc [PR103146]
We need to use the 64-bit DARN to detect failure without bias, but it's
not available in 32-bit mode.

libstdc++-v3/ChangeLog:

	PR libstdc++/103146
	* src/c++11/random.cc: Check __powerpc64__ not __powerpc__.
2021-11-09 14:40:33 +00:00
Jonathan Wakely
3439657b02 libstdc++: Support getentropy and arc4random in std::random_device
This adds additional "getentropy" and "arc4random" tokens to
std::random_device. The former is supported on Glibc and OpenBSD (and
apparently wasm), and the latter is supported on various BSDs.

libstdc++-v3/ChangeLog:

	* acinclude.m4 (GLIBCXX_CHECK_GETENTROPY, GLIBCXX_CHECK_ARC4RANDOM):
	Define.
	* configure.ac (GLIBCXX_CHECK_GETENTROPY, GLIBCXX_CHECK_ARC4RANDOM):
	Use them.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* src/c++11/random.cc (random_device): Add getentropy and
	arc4random as sources.
	* testsuite/26_numerics/random/random_device/cons/token.cc:
	Check new tokens.
	* testsuite/26_numerics/random/random_device/entropy.cc:
	Likewise.
2021-11-09 14:40:33 +00:00
Jonathan Wakely
8d2d0a6c43 libstdc++: Make spurious std::random_device FAIL less likely
It's possible that independent reads from /dev/random and /dev/urandom
could produce the same value by chance. Retry if that happens. The
chances of it happening twice are miniscule.

libstdc++-v3/ChangeLog:

	* testsuite/26_numerics/random/random_device/cons/token.cc:
	Retry if random devices produce the same value.
2021-11-09 14:40:33 +00:00
Rasmus Villemoes
cc6b8cd9a2 libstdc++: only define _GLIBCXX_HAVE_TLS for VxWorks >= 6.6
According to
https://gcc.gnu.org/legacy-ml/gcc-patches/2008-03/msg01698.html, the
TLS support, including the __tls_lookup function, was added to VxWorks
in 6.6.

It certainly doesn't exist on our VxWorks 5 platform, but the fallback
code in eh_globals.cc using __gthread_key_create() etc. used to work
just fine.

libstdc++-v3/ChangeLog:

	* config/os/vxworks/os_defines.h (_GLIBCXX_HAVE_TLS): Only
	define for VxWorks >= 6.6.
2021-11-09 09:51:08 +01:00
GCC Administrator
851dff042a Daily bump. 2021-11-06 00:16:24 +00:00
Jonathan Wakely
2b2d97fc54 libstdc++: Fix inconsistent noexcept-specific for valarray begin/end
These declarations should be noexcept after I added it to the
definitions in <valarray>.

libstdc++-v3/ChangeLog:

	* include/bits/range_access.h (begin(valarray), end(valarray)):
	Add noexcept.
2021-11-05 21:44:01 +00:00
Jonathan Wakely
70d6f6e41f libstdc++: Fix pack expansions in tuple_size_v specializations
libstdc++-v3/ChangeLog:

	* include/std/tuple (tuple_size_v): Fix pack expansion.
2021-11-05 21:44:00 +00:00
Jonathan Wakely
2627e3b7fd libstdc++: Add [[unlikely]] attributes to std::random_device routines
libstdc++-v3/ChangeLog:

	* src/c++11/random.cc (__x86_rdrand, __x86_rdseed): Add
	[[unlikely]] attribute.
2021-11-05 18:14:41 +00:00
Jonathan Wakely
5997e6a6ec libstdc++: Add support for POWER9 DARN instruction to std::random_device
The ISA-3.0 instruction set includes DARN ("deliver a random number")
which can be used similarly to the existing support for RDRAND and RDSEED.

libstdc++-v3/ChangeLog:

	* src/c++11/random.cc [__powerpc__] (USE_DARN): Define.
	(__ppc_darn): New function to use POWER9 DARN instruction.
	(Which): Add 'darn' enumerator.
	(which_source): Check for __ppc_darn.
	(random_device::_M_init): Support "darn" and "hw" tokens.
	(random_device::_M_getentropy): Add darn to switch.
	* testsuite/26_numerics/random/random_device/cons/token.cc:
	Check "darn" token.
	* testsuite/26_numerics/random/random_device/entropy.cc:
	Likewise.
2021-11-05 18:14:40 +00:00
Jonathan Wakely
30b8ec68e2 libstdc++: Add xfail to pretty printer tests that fail in C++20
For some reason the type printer for std::string doesn't work in C++20
mode, so std::basic_string<char, char_traits<char>, allocator<char> is
printed out in full rather than being shown as std::string. It's
probably related to the fact that the extern template declarations are
disabled for C++20, but I don't know why that affects GDB.

For now I'm just marking the relevant tests as XFAIL. That requires
adding support for target selectors to individual GDB directives such as
note-test and whatis-regexp-test.

libstdc++-v3/ChangeLog:

	* testsuite/lib/gdb-test.exp: Add target selector support to the
	dg-final directives.
	* testsuite/libstdc++-prettyprinters/80276.cc: Add xfail for
	C++20.
	* testsuite/libstdc++-prettyprinters/libfundts.cc: Likewise.
	* testsuite/libstdc++-prettyprinters/prettyprinters.exp: Tweak
	comment.
2021-11-05 12:22:31 +00:00
GCC Administrator
29a1af24ef Daily bump. 2021-11-05 00:16:36 +00:00
Jonathan Wakely
a634928f5c libstdc++: Fix pretty printing of std::unique_ptr [PR103086]
Since std::tuple started using [[no_unique_address]] the tuple<T*, D>
member of std::unique_ptr<T, D> has two _M_head_impl subobjects, in
different base classes. That means this printer code is ambiguous:

    tuple_head_type = tuple_impl_type.fields()[1].type   # _Head_base
    head_field = tuple_head_type.fields()[0]
    if head_field.name == '_M_head_impl':
        self.pointer = tuple_member['_M_head_impl']

In older versions of GDB it happened to work by chance, because GDB
returned the last _M_head_impl member and std::tuple's base classes are
stored in reverse order, so the last one was the T* element of the
tuple. Since GDB 11 it returns the first _M_head_impl, which is the
deleter element.

The fix is for the printer to stop using an ambiguous field name and
cast the tuple to the correct base class before accessing the
_M_head_impl member.

Instead of fixing this in both UniquePointerPrinter and StdPathPrinter a
new unique_ptr_get function is defined to do it correctly. That is
defined in terms of new tuple_get and _tuple_impl_get functions.

It would be possible to reuse _tuple_impl_get to access each element in
StdTuplePrinter._iterator.__next__, but that already does the correct
casting, and wouldn't be much simpler anyway.

libstdc++-v3/ChangeLog:

	PR libstdc++/103086
	* python/libstdcxx/v6/printers.py (_tuple_impl_get): New helper
	for accessing the tuple element stored in a _Tuple_impl node.
	(tuple_get): New function for accessing a tuple element.
	(unique_ptr_get): New function for accessing a unique_ptr.
	(UniquePointerPrinter, StdPathPrinter): Use unique_ptr_get.
	* python/libstdcxx/v6/xmethods.py (UniquePtrGetWorker): Cast
	tuple to its base class before accessing _M_head_impl.
2021-11-04 22:50:02 +00:00
Jonathan Wakely
f4130a3eb5 libstdc++: Deprecate std::unexpected and handler functions
These functions have been deprecated since C++11, and were removed in
C++17. The proposal P0323 wants to reuse the name std::unexpected for a
class template, so we will need to stop defining the current function
for C++23 anyway.

This marks them as deprecated for C++11 and up, to warn users they won't
continue to be available. It disables them for C++17 and up, unless the
_GLIBCXX_USE_DEPRECATED macro is defined.

The <unwind-cxx.h> header uses std::unexpected_handler in the public
API, but since that type is the same as std::terminate_handler we can
just use that instead, to avoid warnings about it being deprecated.

libstdc++-v3/ChangeLog:

	* doc/xml/manual/evolution.xml: Document deprecations.
	* doc/html/*: Regenerate.
	* libsupc++/exception (unexpected_handler, unexpected)
	(get_unexpected, set_unexpected): Add deprecated attribute.
	Do not define without _GLIBCXX_USE_DEPRECATED for C++17 and up.
	* libsupc++/eh_personality.cc (PERSONALITY_FUNCTION): Disable
	deprecated warnings.
	* libsupc++/eh_ptr.cc (std::rethrow_exception): Likewise.
	* libsupc++/eh_terminate.cc: Likewise.
	* libsupc++/eh_throw.cc (__cxa_init_primary_exception):
	Likewise.
	* libsupc++/unwind-cxx.h (struct __cxa_exception): Use
	terminate_handler instead of unexpected_handler.
	(struct __cxa_dependent_exception): Likewise.
	(__unexpected): Likewise.
	* testsuite/18_support/headers/exception/synopsis.cc: Add
	dg-warning for deprecated warning.
	* testsuite/18_support/exception_ptr/60612-unexpected.cc:
	Disable deprecated warnings.
	* testsuite/18_support/set_unexpected.cc: Likewise.
	* testsuite/18_support/unexpected_handler.cc: Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/lambda/lambda-eh2.C: Add dg-warning for new
	deprecation warnings.
	* g++.dg/cpp0x/noexcept06.C: Likewise.
	* g++.dg/cpp0x/noexcept07.C: Likewise.
	* g++.dg/eh/forced3.C: Likewise.
	* g++.dg/eh/unexpected1.C: Likewise.
	* g++.old-deja/g++.eh/spec1.C: Likewise.
	* g++.old-deja/g++.eh/spec2.C: Likewise.
	* g++.old-deja/g++.eh/spec3.C: Likewise.
	* g++.old-deja/g++.eh/spec4.C: Likewise.
	* g++.old-deja/g++.mike/eh33.C: Likewise.
	* g++.old-deja/g++.mike/eh34.C: Likewise.
	* g++.old-deja/g++.mike/eh50.C: Likewise.
	* g++.old-deja/g++.mike/eh51.C: Likewise.
2021-11-04 20:53:29 +00:00
Jonathan Wakely
b57899f30f libstdc++: Consolidate duplicate metaprogramming utilities
Currently std::variant uses __index_of<T, Types...> to find the first
occurence of a type in a pack, and __exactly_once<T, Types...> to check
that there is no other occurrence.

We can reuse the __find_uniq_type_in_pack<T, Types...>() function for
both tasks, and remove the recursive templates used to implement
__index_of and __exactly_once.

libstdc++-v3/ChangeLog:

	* include/bits/utility.h (__find_uniq_type_in_pack): Move
	definition to here, ...
	* include/std/tuple (__find_uniq_type_in_pack): ... from here.
	* include/std/variant (__detail__variant::__index_of): Remove.
	(__detail::__variant::__exactly_once): Define using
	__find_uniq_type_in_pack instead of __index_of.
	(get<T>, get_if<T>, variant::__index_of): Likewise.
2021-11-04 18:14:50 +00:00
Jonathan Wakely
09aab7e699 libstdc++: Optimize std::tuple_element and std::tuple_size_v
This reduces the number of class template instantiations needed for code
using tuples, by reusing _Nth_type in tuple_element and specializing
tuple_size_v for tuple, pair and array (and const-qualified versions of
them).

Also define the _Nth_type primary template as a complete type (but with
no nested 'type' member).  This avoids "invalid use of incomplete type"
errors for out-of-range specializations of tuple_element. Those errors
would probably be confusing and unhelpful for users. We already have
a user-friendly static assert in tuple_element itself.

Also ensure that tuple_size_v is available whenever tuple_size is (as
proposed by LWG 3387). We already do that for tuple_element_t.

libstdc++-v3/ChangeLog:

	* include/bits/stl_pair.h (tuple_size_v): Define partial
	specializations for std::pair.
	* include/bits/utility.h (_Nth_type): Move definition here
	and define primary template.
	(tuple_size_v): Move definition here.
	* include/std/array (tuple_size_v): Define partial
	specializations for std::array.
	* include/std/tuple (tuple_size_v): Move primary template to
	<bits/utility.h>.  Define partial specializations for
	std::tuple.
	(tuple_element): Change definition to use _Nth_type.
	* include/std/variant (_Nth_type): Move to <bits/utility.h>.
	(variant_alternative, variant): Adjust qualification of
	_Nth_type.
	* testsuite/20_util/tuple/element_access/get_neg.cc: Prune
	additional errors from _Nth_type.
2021-11-04 18:14:50 +00:00
Jonathan Wakely
a45d577b2b libstdc++: Refactor emplace-like functions in std::variant
libstdc++-v3/ChangeLog:

	* include/std/variant (__detail::__variant::__emplace): New
	function template.
	(_Copy_assign_base::operator=): Reorder conditions to match
	bulleted list of effects in the standard. Use __emplace instead
	of _M_reset followed by _Construct.
	(_Move_assign_base::operator=): Likewise.
	(__construct_by_index): Remove.
	(variant::emplace): Use __emplace instead of _M_reset followed
	by __construct_by_index.
	(variant::swap): Hoist valueless cases out of visitor. Use
	__emplace to replace _M_reset followed by _Construct.
2021-11-04 09:36:10 +00:00
Jonathan Wakely
30ab6d9e43 libstdc++: Optimize std::variant traits and improve diagnostics
By defining additional partial specializations of _Nth_type we can
reduce the number of recursive instantiations needed to get from N to 0.
We can also use _Nth_type in variant_alternative, to take advantage of
that new optimization.

By adding a static_assert to variant_alternative we get a nicer error
than 'invalid use of incomplete type'.

By defining partial specializations of std::variant_size_v for the
common case we can avoid instantiating the std::variant_size class
template.

The __tuple_count class template and __tuple_count_v variable template
can be simplified to a single variable template, __count.

By adding a deleted constructor to the _Variant_union primary template
we can (very slightly) improve diagnostics for invalid attempts to
construct a std::variant with an out-of-range index. Instead of a
confusing error about "too many initializers for ..." we get a call to a
deleted function.

By using _Nth_type instead of variant_alternative (for cv-unqualified
variant types) we avoid instantiating variant_alternative.

By adding deleted overloads of variant::emplace we get better
diagnostics for emplace<invalid-index> or emplace<invalid-type>. Instead
of getting errors explaining why each of the four overloads wasn't
valid, we just get one error about calling a deleted function.

libstdc++-v3/ChangeLog:

	* include/std/variant (_Nth_type): Define partial
	specializations to reduce number of instantiations.
	(variant_size_v): Define partial specializations to avoid
	instantiations.
	(variant_alternative): Use _Nth_type. Add static assert.
	(__tuple_count, __tuple_count_v): Replace with ...
	(__count): New variable template.
	(_Variant_union): Add deleted constructor.
	(variant::__to_type): Use _Nth_type.
	(variant::emplace): Use _Nth_type. Add deleted overloads for
	invalid types and indices.
2021-11-04 09:36:09 +00:00