14 Commits

Author SHA1 Message Date
Peng Liu
9e3982d9ae
[libc++] Replace __libcpp_{ctz, clz} with __builtin_{ctzg, clzg} (#133920)
`__libcpp_{ctz, clz}` were previously used as fallbacks for `__builtin_{ctzg, clzg}` to ensure compatibility with older compilers (Clang 18 and earlier), as `__builtin_{ctzg, clzg}` became available in Clang 19. Now that support for Clang 18 has been officially dropped in #130142, we can now safely  replace all instances of `__libcpp_{ctz, clz}` with `__count{l,r}_zero` (which internally call `__builtin_{ctzg, clzg}` and eliminate the fallback logic.

Closes #131179.
2025-04-18 20:57:05 -04:00
Nikolas Klauser
8fc2538f33
Reapply "[libc++] Optimize num_put integral functions" (#131613) (#133572)
This reverts commit d1156fcb56891fb1a426c3e8331a51d47f98a1b8.

This patch fixes the reported incorrect formatting changes and adds
tests for them. The performance should be unaffected, since there are no
significant changes required to fix the bugs.

Specifically, a `>` was changed to a `>=` to also add a `+` in the zero
case, and we're checking for zero now before printing the octal and
hexadecimal prefixes.

Closes #131710
2025-04-11 15:35:58 +02:00
Alexander Kornienko
d1156fcb56
Revert "[libc++] Optimize num_put integral functions" (#131613)
Reverts llvm/llvm-project#120859

This change breaks formatting of `0` with `std::showbase` + `std::hex`
or `std::oct`, as well as `+0` with `std::showpos`. I believe the new
behavior is violating the standard. See
https://github.com/llvm/llvm-project/pull/120859#issuecomment-2723970242
and later comments for details and explanation.
2025-03-18 02:05:51 +01:00
Nikolas Klauser
15edf8725a
[libc++] Optimize num_put integral functions (#120859)
```
-------------------------------------------------------
Benchmark                              old          new
-------------------------------------------------------
BM_num_put<bool>                   76.2 ns      32.0 ns
BM_num_put<long>                   76.9 ns      33.1 ns
BM_num_put<long long>              77.9 ns      34.2 ns
BM_num_put<unsigned long>          78.4 ns      33.1 ns
BM_num_put<unsigned long long>     78.0 ns      34.4 ns
BM_num_put<double>                  224 ns       228 ns
BM_num_put<long double>             239 ns       230 ns
BM_num_put<const void*>            68.7 ns      35.1 ns
```

Fixes #40109.
2025-03-05 14:18:49 +01:00
Nikolas Klauser
e99c4906e4
[libc++] Granularize <cstddef> includes (#108696) 2024-10-31 02:20:10 +01:00
Nikolas Klauser
ba87515fea
[libc++][RFC] Always define internal feature test macros (#89178)
Currently, the library-internal feature test macros are only defined if
the feature is not available, and always have the prefix
`_LIBCPP_HAS_NO_`. This patch changes that, so that they are always
defined and have the prefix `_LIBCPP_HAS_` instead. This changes the
canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means
that using an undefined macro (e.g. due to a missing include) is
diagnosed now. While this is rather unlikely currently, a similar change
in `<__configuration/availability.h>` caught a few bugs. This also
improves readability, since it removes the double-negation of `#ifndef
_LIBCPP_HAS_NO_FEATURE`.

The current patch only touches the macros defined in `<__config>`. If
people are happy with this approach, I'll make a follow-up PR to also
change the macros defined in `<__config_site>`.
2024-10-12 09:49:52 +02:00
Louis Dionne
d6832a611a
[libc++][modules] Modularize <cstddef> (#107254)
Many headers include `<cstddef>` just for size_t, and pulling in
additional content (e.g. the traits used for std::byte) is unnecessary.
To solve this problem, this patch splits up `<cstddef>` into
subcomponents so that headers can include only the parts that they
actually require.

This has the added benefit of making the modules build a lot stricter
with respect to IWYU, and also providing a canonical location where we
define `std::size_t` and friends (which were previously defined in
multiple headers like `<cstddef>` and `<ctime>`).

After this patch, there's still many places in the codebase where we
include `<cstddef>` when `<__cstddef/size_t.h>` would be sufficient.
This patch focuses on removing `<cstddef>` includes from __type_traits
to make these headers non-circular with `<cstddef>`. Additional
refactorings can be tackled separately.
2024-09-05 08:28:33 -04:00
Louis Dionne
37dca605c9
[libc++] Clean up includes of <__assert> (#80091)
Originally, we used __libcpp_verbose_abort to handle assertion failures.
That function was declared from all public headers. Since we don't use
that mechanism anymore, we don't need to declare __libcpp_verbose_abort
from all public headers, and we can clean up a lot of unnecessary
includes.

This patch also moves the definition of the various assertion categories
to the <__assert> header, since we now rely on regular IWYU for these
assertion macros.

rdar://105510916
2024-02-29 10:12:22 -05:00
Konstantin Varlamov
4f215fdd62
[libc++][hardening] Categorize more assertions. (#75918)
Also introduce `_LIBCPP_ASSERT_PEDANTIC` for assertions violating which
results in a no-op or other benign behavior, but which may nevertheless
indicate a bug in the invoking code.
2024-01-05 16:29:23 -08:00
Nikolas Klauser
6256ccfd4f [libc++][NFC] Update the remaining enable_ifs
This brings most of the enable_ifs in libc++ to the same style.

Reviewed By: #libc, ldionne

Spies: ldionne, libcxx-commits

Differential Revision: https://reviews.llvm.org/D157753
2023-09-01 17:51:17 -07:00
varconst
cd0ad4216c [libc++][hardening][NFC] Introduce _LIBCPP_ASSERT_UNCATEGORIZED.
Replace most uses of `_LIBCPP_ASSERT` with
`_LIBCPP_ASSERT_UNCATEGORIZED`.

This is done as a prerequisite to introducing hardened mode to libc++.
The idea is to make enabling assertions an opt-in with (somewhat)
fine-grained controls over which categories of assertions are enabled.
The vast majority of assertions are currently uncategorized; the new
macro will allow turning on `_LIBCPP_ASSERT` (the underlying mechanism
for all kinds of assertions) without enabling all the uncategorized
assertions (in the future; this patch preserves the current behavior).

Differential Revision: https://reviews.llvm.org/D153816
2023-06-28 15:10:31 -07:00
Nikolas Klauser
eb65912e41 [libc++] Move __errc to __system_error/errc.h
This file was added before we started granularizing the headers, but is essentially just a granularized header. This moves the header to the correct place.

Reviewed By: #libc, EricWF

Spies: libcxx-commits, arichardson, mikhail.ramalho

Differential Revision: https://reviews.llvm.org/D146395
2023-04-10 19:23:42 +02:00
Mark de Wever
866fbb8779 [NFC][libc++] Formats granularized charconv.
Reviewed By: #libc, Mordante

Differential Revision: https://reviews.llvm.org/D146153
2023-03-16 18:56:30 +01:00
Mark de Wever
f7efcaca77 [libc++][charconv] Granularizes the header.
Having the header granularized makes it possible to remove the
dependency on this header in <format>. This <format> header gets
included in more headers due to more usage of std::formatter in the
library. This should reduce the number of transitive includes.

Note formatting the new headers will be done in a followup patch.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D145590
2023-03-15 18:01:53 +01:00