That type trait represents whether move-assigning an object is
equivalent to destroying it and then move-constructing a new one from
the same argument. This will be useful in a few places where we may want
to destroy + construct instead of doing an assignment, in particular
when implementing some container operations in terms of relocation.
This is effectively adding a library emulation of P2786R12's
is_replaceable trait, similarly to what we do for trivial relocation.
Eventually, we can replace this library emulation by the real
compiler-backed trait.
This is building towards #129328.
We can use the `__is_nothrow_convertible` builtin unconditionally now,
which makes the implementation very simple, so there isn't much of a
need to keep a separate header around.
This patch makes the __config_site header modular, which solves various
problems with non-modular headers. This requires going back to
generating the modulemap file, since we only know how to make
__config_site modular when we're not using the per-target runtime dir.
The patch also adds a test that we support
-Wnon-modular-include-in-module, which warns about non-modular includes
from modules.
---------
Co-authored-by: Konstantin Varlamov <varconst@apple.com>
We forward declare `reference_wrapper` in multiple places already. This
moves the declaration to the canonical place and removes unnecessary
includes of `__functional/reference_wrapper.h`.
This implements the loading of the tzdata.zi file and store its contents
in the tzdb struct.
This adds all required members except:
- the leap seconds,
- the locate_zone, and
- current_zone.
The class time_zone is incomplete and only contains the parts needed for
storing the parsed data.
The class time_zone_link is fully implemented including its non-member
functions.
Implements parts of:
- P0355 Extending <chrono> to Calendars and Time Zones
- P1614 The Mothership has Landed
Implements:
- P1982 Rename link to time_zone_link
This patch introduces a new trait to represent whether a type is
trivially
relocatable, and uses that trait to optimize the growth of a std::vector
of trivially relocatable objects.
```
--------------------------------------------------
Benchmark old new
--------------------------------------------------
bm_grow<int> 1354 ns 1301 ns
bm_grow<std::string> 5584 ns 3370 ns
bm_grow<std::unique_ptr<int>> 3506 ns 1994 ns
bm_grow<std::deque<int>> 27114 ns 27209 ns
```
This also changes to order of moving and destroying the objects when
growing the vector. This should not affect our conformance.
The <__threading_support> header is a huge beast and it's really
difficult to navigate. I find myself struggling to find what I want
every time I have to open it, and I've been considering splitting it up
for years for that reason.
This patch aims not to contain any functional change. The various
implementations of the threading base are simply moved to separate
headers and then the individual headers are simplified in mechanical
ways. For example, we used to have redundant declarations of all the
functions at the top of `__threading_support`, and those are removed
since they are not needed anymore. The various #ifdefs are also
simplified and removed when they become unnecessary.
Finally, this patch adds documentation for the API we expect from any
threading implementation.
Notable things in this commit:
* refactors `__indirect_binary_left_foldable`, making it slightly
different (but equivalent) to _`indirect-binary-left-foldable`_, which
improves readability (a [patch to the Working Paper][patch] was made)
* omits `__cpo` namespace, since it is not required for implementing
niebloids (a cleanup should happen in 2024)
* puts tests ensuring invocable robustness and dangling correctness
inside the correctness testing to ensure that the algorithms' results
are still correct
[patch]: https://github.com/cplusplus/draft/pull/6734
Locale objects use atomic reference counting, which may be very
expensive in parallel applications. The classic locale is used by
default by all streams and can be very contended. But it's never
destroyed, so the reference counting is also completely pointless on the
classic locale. Currently ~70% of time in the parallel stringstream
benchmarks is spent in locale ctor/dtor. And the execution radically
slows down with more threads.
Avoid reference counting on the classic locale. With this change
parallel benchmarks start to scale with threads.
This is a re-application of f8afc53d641c (aka PR #72112) which was
reverted in 4e0c48b907f1 because it broke the sanitizer builds due
to an initialization order fiasco. This issue has now been fixed by
ensuring that the locale is constinit'ed.
Co-authored-by: Dmitry Vyukov <dvyukov@google.com>
Several experimental headers around std::pmr have been slated for
removal for a while now. This patch actually performs the removal and
cleanups from the code base.
I don't know when, but at some point we lost test coverage to ensue that
all the headers are in the modulemap. This adds a test to make sure all
the headers (excluding a few which shouldn't be part of the modulemap)
are at least mentioned. This also fixes a few headers which bit-rotted
while we were missing the coverage.
When working on an OpenMP offloading backend for standard parallel
algorithms (https://github.com/llvm/llvm-project/pull/66968) we noticed
the need of a generalization of `__is_trivial_plus_operation`. This patch
merges `__is_trivial_equality_predicate` and `__is_trivial_plus_operation`
into `__desugars_to`, and in the future we might extend the latter to support
other binary operations as well.
Co-authored-by: Louis Dionne <ldionne.2@gmail.com>
This patch adds std::experimental::observer_ptr (n4282) and also
fixes LWG2516.
Co-Authored-By: Louis Dionne <ldionne.2@gmail.com>
Differential Revision: https://reviews.llvm.org/D63230
This is an implementation detail for `move_only_function` (and potentially other type-erasing classes).
Reviewed By: #libc, ldionne
Spies: Mordante, ldionne, EricWF, libcxx-commits
Differential Revision: https://reviews.llvm.org/D140259
This implements layout_stride for C++23 and with that completes the
implementation of the C++23 mdspan header. The feature test macro is
added, and the status pages updated.
Co-authored-by: Damien L-G <dalg24@gmail.com>
Differential Revision: https://reviews.llvm.org/D157171
This makes exception handling a lot simpler, since we don't have to convert any exceptions this way. Is also properly handles all the user-thrown exceptions.
Reviewed By: ldionne, #libc
Spies: arichardson, mstorsjo, libcxx-commits
Differential Revision: https://reviews.llvm.org/D154238
This is the first step to implement time zone support in libc++. This
adds the complete tzdb_list class and a minimal tzdb class. The tzdb
class only contains the version, which is used by reload_tzdb.
Next to these classes it contains documentation and build system support
needed for time zone support. The code depends on the IANA Time Zone
Database, which should be available on the platform used or provided by
the libc++ vendors.
The code is labeled as experimental since there will be ABI breaks
during development; the tzdb class needs to have the standard headers.
Implements parts of:
- P0355 Extending <chrono> to Calendars and Time Zones
Addresses:
- LWG3319 Properly reference specification of IANA time zone database
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D154282
This allows including once_flag directly from <__locale> instead of
depending on all of <mutex>, which requires threading. In turn, this
makes it easier to support locales on platforms without threading.
Drive-by change: clang-format once_flag.h and use _LIBCPP_HIDE_FROM_ABI
Differential Revision: https://reviews.llvm.org/D155487
Top level modules don't need `requires` because they're only built when their headers are included.
Reviewed By: ldionne, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D157363
I'm getting a few -Wundefined-inline warnings, and a -Wnon-modular-include-in-module too. Fix all of those.
Reviewed By: Mordante, #libc
Differential Revision: https://reviews.llvm.org/D156508
lldb needs the `std` clang module to make all of libc++ available in the debugger. Make a new header to include the rest of the public headers and use to build a `std` module that just re-exports the rest of libc++.
Reviewed By: Mordante, JDevlieghere, #libc
Differential Revision: https://reviews.llvm.org/D156177
This implements P0009 std::mdspan ((https://wg21.link/p0009)),
a multidimensional span with customization points for
layouts and data access.
Co-authored-by: Damien L-G <dalg24@gmail.com>
Differential Revision: https://reviews.llvm.org/154367
The headers that include_next compiler and OS headers need to be in different top level modules in order to avoid module cycles. e.g. libc++'s stdlib.h will #include_next stdlib.h from the compiler and then the C library. Either of those are likely to include stddef.h, which will come back up to the libc++ module map and create a module cycle. Putting stdlib.h and stddef.h (and the rest of the C standard library headers) in top level modules resolves this by letting the order go cxx_stdlib_h -> os_stdlib_h -> cxx_stddef_h -> os_stddef_h.
All of those headers' dependencies then need to be moved into top level modules themselves to avoid module cycles between the new top level level cstd modules. This starts to get complicated, as the libc++ C headers, by standard, have to include many of the C++ headers, which include the private detail headers, which are intertwined. e.g. some `__algorithm` headers include `__memory` headers and vice versa.
Make top level modules for all of the libc++ headers to easily guarantee that the modules aren't cyclic.
Add enough module exports to fix `check-cxx` and `run-buildbot generic-modules`.
`__stop_token/intrusive_shared_ptr.h` uses `__atomic/atomic.h` but has no include path to it. Add that include.
`math.h` absorbs `bits/atomic_wide_counter.h` on some platforms that don't have modules, work around that by including `math.h` in `__threading_support`.
<mutex> doesn't actually require threads, there are a few pieces like once_flag that work without threads. Remove the requirement from its module.
AIX is no longer able to support modular builds.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D144322
- add the `from_range_t` constructors and the related deduction guides;
- add the `insert_range`/`assign_range`/etc. member functions.
(Note: this patch is split from https://reviews.llvm.org/D142335)
Differential Revision: https://reviews.llvm.org/D149830
This commit implements default_accessor in support of C++23 mdspan
(https://wg21.link/p0009). default_accessor is the trivial accessor
using plain pointers and reference to element types.
Co-authored-by: Damien L-G <dalg24@gmail.com>
Differential Revision: https://reviews.llvm.org/D153935
This is a preparation for
P2093R14 Formatted output
When the output of print is to the terminal it needs to use the native
API. This means transcoding UTF-8 to UTF-16 on Windows. The encoder's
interface is modeled after
P2728 Unicode in the Library, Part 1: UTF Transcoding
But only the required part for P2093R14 is implemented.
On Windows wchar_t is 16 bits, in order to test on platforms where
wchar_t is 32 bits the transcoder has support for char16_t. It also adds
and UTF-8 to UTF-32 encoder which is useful for other tests.
Note it is possible to use <codecvt> for transcoding, but that header is
deprecated. So rather write new code that is not deprecated; the hard
part, decoding, has already been done. The <codecvt> header also
requires locale support while the new code works without including
<locale>.
Note the current transcoder implementation can be optimized since it
basically does UTF-8 -> UTF-32 -> UTF-16. The first goal is to have a
working implementation. Since it's not part of the ABI it's possible to
do the optimization later.
Depends on D149672
Reviewed By: ldionne, tahonermann, #libc
Differential Revision: https://reviews.llvm.org/D150031
