THis fixes teh following error seen with Clang:
error: function '_S_convert<std::basic_string_view<char8_t>>' with deduced
return type cannot be used before it is defined
return string_type(_S_convert(std::u8string_view(__str)));
^
libstdc++-v3/ChangeLog:
* include/bits/fs_path.h (path::_S_convert(T)): Avoid recursive
call to function with deduced return type.
A recently approved change for the C++23 working draft.
libstdc++-v3/ChangeLog:
* include/bits/basic_string.h (__cpp_lib_string_resize_and_overwrite):
Define for C++23.
(basic_string::resize_and_overwrite): Declare.
* include/bits/basic_string.tcc (basic_string::resize_and_overwrite):
Define.
* include/std/version (__cpp_lib_resize_and_overwrite): Define
for C++23.
* testsuite/21_strings/basic_string/capacity/char/resize_and_overwrite.cc:
New test.
This implements the changes in P2231R1 which make std::variant fully
constexpr in C++20.
We need to replace placement new with std::construct_at, but that isn't
defined for C++17. Use std::_Construct instead, which forwards to
std::construct_at in C++20 mode (since the related changes to make
std::optional fully constexpr, in r12-4389).
We also need to replace the untyped char buffer in _Uninitialized with a
union, which can be accessed in constexpr functions. But the union needs
to have a non-trivial destructor if its variant type is non-trivial,
which means that the _Variadic_union also needs a non-trivial
destructor. This adds a constrained partial specialization of
_Variadic_union for the C++20-only case where a non-trivial destructor
is needed.
We can't use concepts to constrain the specialization (or the primary
template's destructor) in C++17, so retain the untyped char buffer
solution for C++17 mode.
libstdc++-v3/ChangeLog:
* include/std/variant (__cpp_lib_variant): Update value for
C++20.
(__variant_cast, __variant_construct): Add constexpr for C++20.
(__variant_construct_single, __construct_by_index) Likewise. Use
std::_Construct instead of placement new.
(_Uninitialized<T, false>) [__cplusplus >= 202002]: Replace
buffer with a union and define a destructor.
(_Variadic_union) [__cplusplus >= 202002]: Add a specialization
for non-trivial destruction.
(_Variant_storage::__index_of): New helper variable template.
(_Variant_storage::~_Variant_storage()): Add constexpr.
(_Variant_storage::_M_reset()): Likewise.
(_Copy_ctor_base, _Move_ctor_base): Likewise.
(_Copy_assign_base, _Move_assign_base): Likewise.
(variant, swap): Likewise.
* include/std/version (__cpp_lib_variant): Update value for
C++20.
* testsuite/20_util/optional/version.cc: Check for exact value
in C++17.
* testsuite/20_util/variant/87619.cc: Increase timeout for
C++20 mode.
* testsuite/20_util/variant/constexpr.cc: New test.
* testsuite/20_util/variant/version.cc: New test.
The __variant_construct_by_index helper function sets the new index
before constructing the new object. This means that if the construction
throws then the exception needs to be caught, so the index can be reset
to variant_npos, and then the exception rethrown. This means callers are
responsible for restoring the variant's invariants and they need the
overhead of a catch handler and a rethrow.
If we don't set the index until after construction completes then the
invariant is never broken, and callers can ignore the exception and let
it propagate. The callers all call _M_reset() first, which sets index to
variant_npos as required while the variant is valueless.
We need to be slightly careful here, because changing the order of
operations in __variant_construct_by_index and removing the try-block
from variant::emplace<I> changes an implicit ABI contract between those
two functions. If the linker were to create an executable containing an
instantiation of the old __variant_construct_by_index and an
instantiation of the new variant::emplace<I> code then we would have a
combination that breaks the invariant and doesn't have the exception
handling to restore it. To avoid this problem, we can rename the
__variant_construct_by_index function so that the new emplace<I> code
calls a new symbol, and is unaffected by the behaviour of the old
symbol.
libstdc++-v3/ChangeLog:
* include/std/variant (__detail::__variant::__get_storage):
Remove unused function.
(__variant_construct_by_index): Set index after construction is
complete. Rename to ...
(__detail::__variant::__construct_by_index): ... this.
(variant): Use new name for __variant_construct_by_index friend
declaration. Remove __get_storage friend declaration.
(variant::emplace): Use new name and remove try-blocks.
These functions aren't used, and accessing the storage as a void* isn't
compatible with C++20 constexpr requirements anyway, so we're unlikely
to ever start using them in future.
libstdc++-v3/ChangeLog:
* include/std/variant (_Variant_storage::_M_storage()): Remove.
(__detail::__variant::__get_storage): Remove.
(variant): Remove friend declaration of __get_storage.
I've been experimenting with a change to make all inline functions
implicitly constexpr; this revealed that we are instantiating too
aggressively for speculative constant evaluation, leading to ordering
difficulties with e.g. is_a_helper<cgraph_node*>::test. This patch tries to
avoid such instantiation until we actually need the function definition to
determine whether a call is constant, by limiting the initial instantiation
of all used functions to manifestly-constant-evaluated expressions, and
checking whether the function arguments are constant before instantiating
the function.
This change resulted in a change in the diagnostics for a few library tests
due to instantiating the function with the static_assert later (during
constant evaluation) than we did before (during instantiation of the
intermediate function).
gcc/cp/ChangeLog:
* constexpr.c (cxx_bind_parameters_in_call): Replace
new_call parameter with fun.
(cxx_eval_call_expression): Call it before instantiation.
(cxx_eval_outermost_constant_expr): Only instantiate fns
when manifestly_const_eval.
* typeck2.c (check_narrowing): This context is manifestly
constant-evaluated.
libstdc++-v3/ChangeLog:
* testsuite/20_util/integer_comparisons/greater_equal_neg.cc:
* testsuite/20_util/integer_comparisons/greater_neg.cc:
* testsuite/20_util/integer_comparisons/less_equal_neg.cc:
Adjust expected message.
* testsuite/lib/prune.exp: Prune 'in constexpr expansion'.
gcc/testsuite/ChangeLog:
* g++.dg/ext/vla22.C: Don't expect a narrowing error.
* g++.dg/cpp0x/constexpr-inst1.C: New test.
libstdc++-v3/ChangeLog:
* include/std/variant (__variant::__get(in_place_index_t<N>, U&&)):
Rename to __get_n and remove first argument. Replace pair of
overloads with a single function using 'if constexpr'.
(__variant::__get(Variant&&)): Adjust to use __get_n.
Since r12-4065 std::basic_string is always nothrow-move-constructible,
so filesystem::path is too.
That also means that path::_S_convert(T) is noexcept when returning its
argument, because T is either a basci_string or basic_string_view, and
will be moved into the return value.
libstdc++-v3/ChangeLog:
* include/bits/fs_path.h (path(path&&)): Make unconditionally
noexcept.
(path::_S_convert(T)): Add condtional noexcept.
This function was supposed to check whether the parameter's value type
is the same as path::value_type, and therefore needs no conversion.
Instead it checks whether the parameter is the same as its own value
type, which is never true. This means we incorrectly return a string
view for the case where T is path::string_type, instead of just
returning the string itself. The only place that happens is
path::_S_convert_loc for Windows, where we call _S_convert with a
std::wstring rvalue.
This fixes the condition in _S_convert(T).
libstdc++-v3/ChangeLog:
PR libstdc++/102743
* include/bits/fs_path.h (path::_S_convert(T)): Fix condition
for returning the same string unchanged.
The out-of-class definitions of the static constants are redundant if
the __cpp_inline_variables feature is supported, so use that macro to
decide whether to define them or not.
libstdc++-v3/ChangeLog:
* include/bits/regex.h: Check __cpp_inline_variables instead of
__cplusplus.
This implements the changes in P2231R1 which make std::optional fully
constexpr in C++20.
libstdc++-v3/ChangeLog:
* include/bits/stl_construct.h (_Construct): Use
std::construct_at when constant evaluated.
* include/std/optional (_Storage, _Optional_payload, optional):
Add constexpr as specified by P2231R1.
* include/std/version (__cpp_lib_optional): Update value for
C++20.
* testsuite/20_util/optional/requirements.cc: Check feature test
macro.
* testsuite/20_util/optional/constexpr/assign.cc: New test.
* testsuite/20_util/optional/constexpr/cons/conv.cc: New test.
* testsuite/20_util/optional/constexpr/modifiers.cc: New test.
* testsuite/20_util/optional/constexpr/swap.cc: New test.
* testsuite/20_util/optional/version.cc: New test.
The changes in r12-4381 were intended to reduce memory usage, but
replacing the __contiguous constant in __string_from_range with the new
__is_contiguous variable template caused a regression. The old code
checked is_pointer_v<decltype(std::__niter_base(__first))> but he new
code just checks is_pointer_v<_InputIterator>. This means that we no
longer recognise basic_string::iterator and vector::iterator as
contiguous, and so return a temporary basic_string instead of a
basic_string_view. This only affects C++17 mode, because the
std::contiguous_iterator concept is used in C++20 which gives the right
answer for __normal_iterator (and more types as well).
The fix is to specialize the new __is_contiguous variable template so it
is true for __normal_iterator<T*, C> specializations. The new partial
specializations are defined for C++20 too, because it should be cheaper
to match the partial specialization than to check whether the
std::contiguous_iterator concept is satisfied.
libstdc++-v3/ChangeLog:
* include/bits/fs_path.h (__detail::__is_contiguous): Add
partial specializations for pointers and __normal_iterator.
Adjust the __detail::__effective_range overloads so they always return a
string or string view using std::char_traits, because we don't care
about the traits of an incoming string.
Use std::contiguous_iterator in the __effective_range(const Source&)
overload, to allow returning a basic_string_view in more cases. For the
non-contiguous casecl in both __effective_range and __string_from_range,
return a std::string instead of std::u8string when the value type of the
range is char8_t. These changes avoid unnecessary basic_string
temporaries.
Also simplify __string_from_range(Iter, Iter) to not need
std::__to_address for the contiguous case.
Combine the _S_convert(string_type) and _S_convert(const T&) overloads
into a single _S_convert(T) function which also avoids the dangling
view problem of PR 102592 (should that recur somehow).
libstdc++-v3/ChangeLog:
* include/bits/fs_path.h (__detail::__is_contiguous): New
variable template to identify contiguous iterators.
(__detail::__unified_char8_t): New alias template to decide when
to treat char8_t as char without encoding conversion.
(__detail::__effective_range(const basic_string<C,T>&)): Use
std::char_traits<C> for returned string view.
(__detail::__effective_range(const basic_string_view<C,T>&)):
Likewise.
(__detail::__effective_range(const Source&)): Use
__is_contiguous to detect mode cases of contiguous iterators.
Use __unified_char8_t to return a std::string instead of
std::u8string.
When creating a path from a pair of non-contiguous iterators we pass the
iterators to _S_convert(Iter, Iter). That function passes the iterators
to __string_from_range to get a contiguous sequence of characters, and
then calls _S_convert(const C*, const C*) to perform the encoding
conversions. If the value type, C, is char8_t, then no conversion is
needed and the _S_convert<char8_t>(const char8_t*, const char8_t*)
specialization casts the pointer to const char* and returns a
std::string_view that refs to the char8_t sequence. However, that
sequence is owned by the std::u8string rvalue returned by
__string_from_range, which goes out of scope when _S_convert(Iter, Iter)
returns. That means the std::string_view is dangling and we get
undefined behaviour when parsing it as a path.
The same problem does not exist for the path members taking a "Source"
argument, because those functions all convert a non-contiguous range
into a basic_string<C> immediately, using __effective_range(__source).
That means that the rvalue string returned by that function is still in
scope for the full expression, so the string_view does not dangle.
The solution for the buggy functions is to do the same thing, and call
__string_from_range immediately, so that the returned rvalue is still in
scope for the lifetime of the string_view returned by _S_convert. To
avoid reintroducing the same problem, remove the _S_convert(Iter, Iter)
overload that calls __string_from_range and returns a dangling view.
libstdc++-v3/ChangeLog:
PR libstdc++/102592
* include/bits/fs_path.h (path::path(Iter, Iter, format))
(path::append(Iter, Iter), path::concat(Iter, Iter)): Call
__string_from_range directly, instead of two-argument overload
of _S_convert.
(path::_S_convert(Iter, Iter)): Remove.
* testsuite/27_io/filesystem/path/construct/102592.C: New test.
This is needed because people still find it necessary to do:
extern "C" {
#include <stdlib.h>
}
libstdc++-v3/ChangeLog:
* include/bits/c++config (__terminate): Add extern "C++".
Also restore the test for 'a < a' that was removed by r12-2537 because
it is ill-formed. We still want to test operator< for tuple, we just
need to not use std::nullptr_t in that tuple type.
libstdc++-v3/ChangeLog:
* testsuite/20_util/tuple/comparison_operators/overloaded.cc:
Restore test for operator<.
* testsuite/20_util/tuple/comparison_operators/overloaded2.cc:
Adjust expected errors for C++20.
The r12-3022 commit only fixed the case where an array is the last
element of the tuple. This fixes the other cases too. We can just define
the move constructor as defaulted, which does the right thing. Changing
the move constructor to be trivial would be an ABI break, but since the
last base class still has a non-trivial move constructor, defining the
derived ones as defaulted doesn't change anything.
libstdc++-v3/ChangeLog:
PR libstdc++/101960
* include/std/tuple (_Tuple_impl(_Tuple_impl&&)): Define as
defauled.
* testsuite/20_util/tuple/cons/101960.cc: Check tuples with
array elements before the last element.
This adds deleted overloads so that the errors for invalid uses of
std::advance and std::distance are easier to understand (see for example
PR 102181).
libstdc++-v3/ChangeLog:
* include/bits/stl_iterator_base_funcs.h (__advance): Add
deleted overload to improve diagnostics.
(__distance): Likewise.
This adds an inline wrapper for std::terminate that doesn't add the
declaration of std::terminate to namespace std. This allows the
library to terminate without including all of <exception>.
libstdc++-v3/ChangeLog:
* include/bits/atomic_timed_wait.h: Remove unused header.
* include/bits/c++config (std:__terminate): Define.
* include/bits/semaphore_base.h: Remove <exception> and use
__terminate instead of terminate.
* include/bits/std_thread.h: Likewise.
* libsupc++/eh_terminate.cc (std::terminate): Use qualified-id
to call __cxxabiv1::__terminate.
We know that if __is_contiguous_iterator is true then we have a pointer
or a __normal_iterator that wraps a pointer, so we don't need to use
std::__to_address.
libstdc++-v3/ChangeLog:
* include/bits/regex.h (basic_regex::assign(Iter, Iter)): Avoid
std::__to_address by using poitner directly or using base()
member of __normal_iterator.
This test uses std::is_integral to decide whether we are testing an
integral or floating-point type. But that fails for __int128 because
is_integral<__int128> is false in strict modes. By using
numeric_limits::is_integer instead we get the right answer for all types
that have a numeric_limits specialization.
We can also simplify the test by removing the unnecessary tag
dispatching.
libstdc++-v3/ChangeLog:
* testsuite/18_support/numeric_limits/lowest.cc: Use
numeric_limits<T>::is_integer instead of is_integral<T>::value.
This adds some debug assertions to basic_regex. They don't actually
diagnose the error in the PR yet, but I have another patch to make them
more effective.
Also change the __glibcxx_assert(false) consistency checks to include a
string literal that tells the user a bit more about why the process
aborted. We could consider adding a __glibcxx_bug or
__glibcxx_internal_error macro for this purpose, but ideally we'll never
hit such bugs anyway so it shouldn't be needed.
libstdc++-v3/ChangeLog:
PR libstdc++/89927
* include/bits/regex.h (basic_regex(const _Ch_type*, size_t)):
Add __glibcxx_requires_string_len assertion.
(basic_regex::assign(InputIterator, InputIterator)): Add
__glibcxx_requires_valid_range assertion.
* include/bits/regex_scanner.tcc (_Scanner::_M_advance())
(_Scanner::_M_scan_normal()): Use string literal in assertions.
The end() function needs to consider whether the underlying vector is
empty, not whether the match_results object is empty. That's because the
underlying vector will always contain at least three elements for a
match_results object that is "ready". It contains three extra elements
which are stored in the vector but are not considered part of sequence,
and so should not be part of the [begin(),end()) range.
libstdc++-v3/ChangeLog:
PR libstdc++/102667
* include/bits/regex.h (match_result::empty()): Optimize by
calling the base function directly.
(match_results::end()): Check _Base_type::empty() not empty().
* testsuite/28_regex/match_results/102667.C: New test.
We don't need to have <wchar.h> support in order to delete overloads
for inserting wide characters into narrow streams.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/std/ostream (operator<<(basic_ostream<char, Tr>&, wchar_t))
(operator<<(basic_ostream<char, Tr>&, const wchar_t*)): Always
define as deleted. Do not check _GLIBCXX_USE_WCHAR_T.
The wchar_t type is defined unconditionally for C++, so there is no
reason for std::wstring_convert and std::wbuffer_convert to be disabled
when <wchar.h> is not usable. It should be possible to use those class
templates with char16_t and char32_t even if wchar_t conversions don't
work.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/bits/locale_conv.h (wstring_convert, wbuffer_convert):
Define unconditionally. Do not check _GLIBCXX_USE_WCHAR_T.
None of these traits depend on libc support for wchar_t, so they should
be defined unconditionally. The wchar_t type is always defined in C++.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/c_global/cstddef [!_GLIBCXX_USE_WCHAR_T]
(__byte_operand<wchar_t>): Define specialization.
* include/std/type_traits (__make_signed<wchar_t>)
(__make_unsigned<wchar_t>): Remove redundant check for
__WCHAR_TYPE__ being defined.
* include/tr1/type_traits [!_GLIBCXX_USE_WCHAR_T]
(__is_integral_helper<wchar_t>): Likewise.
None of these vstring specializations depend on libc support for
wchar_t, so can be enabled unconditionally now that char_traits<wchar_t>
is always available.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/ext/rc_string_base.h [!_GLIBCXX_USE_WCHAR_T]
(__rc_string_base<wchar_t>): Define member function.
* include/ext/vstring.h [!_GLIBCXX_USE_WCHAR_T]
(hash<__gnu_cxx::__wvstring>): Define specialization.
* include/ext/vstring_fwd.h [!_GLIBCXX_USE_WCHAR_T] (__wvstring)
(__wsso_string, __wrc_string): Declare typedefs.
The wstring and wstring_view typedefs should be enabled even if
<wchar.h> isn't supported, because char_traits<wchar_t> works
unconditionally. Similarly, the std::hash specializations for wide
strings do not depend on <wchar.h> support.
Although the primary template works OK for std::char_traits<wchar_t> in
the absence of <wchar.h> support, this patch still defines it as an
explicit specialization for compatibility with declarations that expect
it to be specialized. The explicit specialization just uses the same
__gnu_cxx::char_traits base class as the primary template.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/bits/char_traits.h (char_traits<wchar_t>): Define
explicit specialization unconditionally.
* include/bits/basic_string.h (hash<wstring>): Define
unconditionally. Do not check _GLIBCXX_USE_WCHAR_T.
* include/bits/stringfwd.h (wstring): Likewise.
* include/debug/string (wstring): Likewise.
* include/experimental/string_view (experimental::wstring_view)
(hash<experimental::wstring_view>): Likewise.
* include/std/string (pmr::wstring, hash<pmr::wstring>):
Likewise.
* include/std/string_view (wstring_view, hash<wstring_view>):
Likewise.
This fixes a FAIL when --disable-wchar_t is used.
libstdc++-v3/ChangeLog:
* testsuite/27_io/basic_filebuf/close/81256.cc: Moved to...
* testsuite/27_io/basic_filebuf/close/wchar_t/81256.cc: ...here.
This avoids the tuple-like API for std::pair in the unordered
containers, removing some overly generic code.
The _Select1st projection can figure out the member types of a std::pair
without using decltype(std::get<0>(...)).
We don't need _Select2nd because it's only needed in
_NodeBuilder::_S_build, and that can just access the .second member of
the pair directly. The return type of that function doesn't need to be
deduced by decltype, we can just expose the __node_type typedef of the
node generator.
libstdc++-v3/ChangeLog:
* include/bits/hashtable_policy.h (_Select1st): Replace use of
std::get.
(_Select2nd): Remove.
(_NodeBuilder::_S_build): Use _NodeGenerator::__node_type
typedef instead of deducing it. Remove unnecessary piecewise
construction.
(_ReuseOrAllocNode): Make __node_type public.
(_Map_base): Adjust partial specialization to be able to extract
the mapped_type without using tuple_element.
(_Map_base::at): Define inline
* testsuite/23_containers/unordered_map/requirements/53339.cc:
Remove XFAIL.
* testsuite/23_containers/unordered_multimap/requirements/53339.cc:
Likewise.
This is a step towards restoring support for incomplete types in
unordered containers (PR 53339).
We do not need to instantiate the node type to get its value_type
member, because we know that the value type is the first template
parameter. We can deduce that template argument using a custom trait and
a partial specialization for _Hash_node. If we wanted to support custom
hash node types we could still use typename _Tp::value_type in the
primary template of that trait, but that seems unnecessary.
The other change needed is to defer a static assert at class scope, so
that it is done when the types are complete. We must have a complete
type in the destructor, so we can do it there instead.
libstdc++-v3/ChangeLog:
* include/bits/hashtable.h: Move static assertion to destructor.
* include/bits/hashtable_policy.h: Deduce value type from node
type without instantiating it.
Add a #error directive to ensure that the definitions are not compiled
as C++17, which would prevent them being emitted.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* src/c++11/limits.cc: Fail if __cpp_inline_variables is
defined.
The <bits/ranges_algobase.h> header doesn't need the stream and
streambuf iterators, so don't include the whole of <iterator>.
libstdc++-v3/ChangeLog:
PR libstdc++/92546
* include/bits/ranges_algobase.h: Replace <iterator> with a
subset of the headers it includes.
This is a missing piece of the C++20 <chrono> header.
It would be good to move the code into the compiled library, so that we
don't need <sstream> in <chrono>. It could also use spanstream in C++20,
to avoid memory allocations. That can be changed at a later date.
libstdc++-v3/ChangeLog:
* include/std/chrono (__detail::__units_suffix_misc): New
helper function.
(__detail::__units_suffix): Likewise.
(chrono::operator<<(basic_ostream&, const duration&)): Define.
* testsuite/20_util/duration/io.cc: New test.
This moves the "classic" contents of <chrono> to a new header, so that
<future>, <thread> etc. can get use durations and clocks without
calendar types, time zones, and chrono I/O.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new header.
* include/Makefile.in: Regenerate.
* include/std/chrono (duration, time_point, system_clock)
(steady_clock, high_resolution_clock, chrono_literals, sys_time)
(file_clock, file_time): Move to ...
* include/bits/chrono.h: New file.
* include/bits/atomic_futex.h: Include new header instead of
<chrono>.
* include/bits/atomic_timed_wait.h: Likewise.
* include/bits/fs_fwd.h: Likewise.
* include/bits/semaphore_base.h: Likewise.
* include/bits/this_thread_sleep.h: Likewise.
* include/bits/unique_lock.h: Likewise.
* include/experimental/bits/fs_fwd.h: Likewise.
* include/experimental/chrono: Likewise.
* include/experimental/io_context: Likewise.
* include/experimental/netfwd: Likewise.
* include/experimental/timer: Likewise.
* include/std/condition_variable: Likewise.
* include/std/mutex: Likewise.
* include/std/shared_mutex: Likewise.
GCC Administrator
Jonathan Wakely
Jason Merrill