Commit Graph

31 Commits

Author SHA1 Message Date
Joe Loser d2baefae68
[libc++] Replace _LIBCPP_HAS_NO_CONCEPTS with _LIBCPP_STD_VER > 17. NFCI.
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.

Differential Revision: https://reviews.llvm.org/D121528
2022-03-13 12:32:06 -04:00
Louis Dionne 368faacac7 [libc++] Revert "Protect users from relying on detail headers" & related changes
This commit reverts 5aaefa51 (and also partly 7f285f48e7 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.

Differential Revision: https://reviews.llvm.org/D120683
2022-03-01 08:20:24 -05:00
Christopher Di Bella 5aaefa510e [libcxx][modules] protects users from relying on detail headers
libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.

Differential Revision: https://reviews.llvm.org/D106124
2022-02-26 09:00:25 +00:00
Nikolas Klauser 2a8f9a5e95 [libc++] Implement P0627R6 (Function to mark unreachable code)
Reviewed By: ldionne, Quuxplusone, #libc

Spies: arichardson, mstorsjo, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D119152
2022-02-14 20:52:51 +01:00
Arthur O'Dwyer fa6b9e4010 [libc++] Normalize all our '#pragma GCC system_header', and regression-test.
Now we'll notice if a header forgets to include this magic phrase.

Differential Revision: https://reviews.llvm.org/D118800
2022-02-04 12:27:19 -05:00
Arthur O'Dwyer b2a0cc1c65 [libc++] Guard bits of 598983d7 against _LIBCPP_HAS_NO_CONCEPTS. 2022-02-02 11:19:46 -05:00
Arthur O'Dwyer 38db42d004 [libc++] [NFC] s/_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)/!defined(_LIBCPP_HAS_NO_CONCEPTS)/
Per Discord discussion, we're normalizing on a simple `!defined(_LIBCPP_HAS_NO_CONCEPTS)`
so that we can do a big search-and-replace for `!defined(_LIBCPP_HAS_NO_CONCEPTS)`
back into `_LIBCPP_STD_VER > 17` when we're ready to abandon support for concept-syntax-less
compilers.

Differential Revision: https://reviews.llvm.org/D118748
2022-02-02 11:02:56 -05:00
Nikolas Klauser 598983d7a9 [libc++][P2321R2] Add specializations of basic_common_reference and common_type for pair
Add specializations of basic_common_reference and common_type for pair

Reviewed By: Quuxplusone, Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D117506
2022-02-02 10:47:04 +01:00
Arthur O'Dwyer 4d81a46f7f [libc++] Alphabetize header #includes. NFCI.
The NFC part of D116809. We still want to enforce this in CI,
but the mechanism for that is still to-be-determined.

Differential Revision: https://reviews.llvm.org/D116809
2022-01-10 16:30:38 -05:00
Arthur O'Dwyer cb8a0b0797 [libc++] [ranges] Introduce _LIBCPP_AUTO_CAST(x) for auto(x).
Clang is gaining `auto(x)` support in D113393; sadly there
seems to be no feature-test macro for it. Zhihao is opening
a core issue for that macro.

Use `_LIBCPP_AUTO_CAST` where C++20 specifies we should use `auto(x)`;
stop using `__decay_copy(x)` in those places.
In fact, remove `__decay_copy` entirely. As of C++20, it's purely
a paper specification tool signifying "Return just `x`, but it was
perfect-forwarded, so we understand you're going to have to call
its move-constructor sometimes." I believe there's no reason we'd
ever need to do its operation explicitly in code.

This heisenbugs away a test failure on MinGW; see D112214.

Differential Revision: https://reviews.llvm.org/D115686
2021-12-22 12:29:42 -05:00
Louis Dionne 37e6bd8bc8 [libc++] Add a helper class to write code with the strong exception guarantee
__transaction is a helper class that allows rolling back code in case an
exception is thrown. The main goal is to reduce the clutter when code
needs to be guarded with `#if _LIBCPP_NO_EXCEPTIONS`.

Differential Revision: https://reviews.llvm.org/D115730
2021-12-20 11:17:29 -05:00
Arthur O'Dwyer 4dd901f4d3 [libc++] Fix the noexceptness of __decay_copy.
When `a` was an array type, `__decay_copy(a)` was incorrectly marking itself
noexcept(false), because it is false that `int[10]` is nothrow convertible to `int[10]`
(in fact it is not convertible at all).

We have no tests explicitly for `__decay_copy`, but the new ranges::begin
and ranges::end tests fail before this patch.

Differential Revision: https://reviews.llvm.org/D115658
2021-12-13 17:55:38 -05:00
Nikolas Klauser d2b0df35af [libc++][NFC] Update namespace comments in include/
update the namspace comments in include/

Reviewed By: ldionne, #libc

Spies: smeenai, libcxx-commits

Differential Revision: https://reviews.llvm.org/D114947
2021-12-02 21:06:59 +01:00
Arthur O'Dwyer d8380ad977 [libc++] [P1614] Implement [cmp.alg]'s std::{strong,weak,partial}_order.
This does not include `std::compare_*_fallback`; those are coming later.

There's still an open question of how to implement std::strong_order
for `long double`, which has 80 value bits and 48 padding bits on x86-64,
and which is presumably *not* IEEE 754-compliant on PPC64 and so on.
So that part is left unimplemented.

Differential Revision: https://reviews.llvm.org/D110738
2021-11-22 13:24:28 -05:00
Louis Dionne eb8650a757 [runtimes][NFC] Remove filenames at the top of the license notice
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
2021-11-17 16:30:52 -05:00
Louis Dionne c0f87e8382 [libc++] Remove _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
All supported compilers support spaceship in C++20 nowadays.

Differential Revision: https://reviews.llvm.org/D113938
2021-11-17 10:59:57 -05:00
Louis Dionne 2999b7307f [libc++] Make __decay_copy constexpr
This is going to be necessary to implement some range adaptors.
As a fly-by fix, rename _LIBCPP_INLINE_VISIBILITY to _LIBCPP_HIDE_FROM_ABI
and remove a redundant inline keyword.

Differential Revision: https://reviews.llvm.org/D112650
2021-10-27 17:32:08 -04:00
Louis Dionne f4c1258d56 [libc++] Add an option to disable wide character support in libc++
Some embedded platforms do not wish to support the C library functionality
for handling wchar_t because they have no use for it. It makes sense for
libc++ to work properly on those platforms, so this commit adds a carve-out
of functionality for wchar_t.

Unfortunately, unlike some other carve-outs (e.g. random device), this
patch touches several parts of the library. However, despite the wide
impact of this patch, I still think it is important to support this
configuration since it makes it much simpler to port libc++ to some
embedded platforms.

Differential Revision: https://reviews.llvm.org/D111265
2021-10-12 06:08:23 -04:00
Joe Loser 0d450aa641
[libc++] P2401: conditional noexcept for std::exchange
Implement P2401 which adds a `noexcept` specification to
`std::exchange`. Treated as a defect fix which is the motivation for
applying this change to all standards mode rather than just C++23 or
later as the paper suggests.

Reviewed By: Quuxplusone, Mordante, #libc

Differential Revision: https://reviews.llvm.org/D111481
2021-10-11 14:34:45 -04:00
Louis Dionne 1e628d0c14 [libc++] Do not enable P1951 before C++23, since it's a breaking change
In reaction to the issues raised by Richard in https://llvm.org/D109066,
this commit does not apply P1951 as a DR in previous standard modes,
since it breaks valid code.

I do believe it should be applied as a DR, however ideally we'd get some
sort of statement from the Committee to this effect (and all implementations
would behave consistently). In the meantime, only implement P1951 starting
with C++23 -- we can always come back and apply it as a DR if that's what
the Committee says.

Differential Revision: https://reviews.llvm.org/D110347
2021-09-27 17:06:44 -04:00
Kent Ross f4abdb0c07 [libc++][spaceship] Implement std::pair::operator<=>
Implements parts of P1614, including synth-three-way and three way comparison for std::pair.

Reviewed By: #libc, Quuxplusone, Mordante

Differential Revision: https://reviews.llvm.org/D107721
2021-09-22 22:36:46 -07:00
Louis Dionne cb793e1a36 [libc++][NFCI] Remove uses of _LIBCPP_INLINE_VAR
All supported compilers provide support for inline variables in C++17 now.
Also, as a fly-by fix, replace some uses of _LIBCPP_CONSTEXPR by just
constexpr.

The only exception in this patch is `std::ignore`, which is provided
prior to C++17. Since it is defined in an anonymous namespace, it always
has internal linkage anyway, so using an inline variable there doesn't
provide any benefit. Instead, `inline` was removed entirely on `std::ignore`.

Differential Revision: https://reviews.llvm.org/D110243
2021-09-22 16:03:00 -04:00
Louis Dionne 312ad74aea [libc++] Implement P1951, default arguments for pair's forwarding constructor
Differential Revision: https://reviews.llvm.org/D109066
2021-09-09 08:28:22 -04:00
Louis Dionne 3557c7c122 [libc++] Remove workarounds for [[nodebug]] not working properly on typedefs in older Clangs
Clang used to support [[nodebug]] everywhere except on typedefs. Since
we don't support such old Clangs anymore, we can get rid of _LIBCPP_NODEBUG_TYPE
in favour of always using _LIBCPP_NODEBUG.

Differential Revision: https://reviews.llvm.org/D108996
2021-09-01 10:51:09 -04:00
Louis Dionne 8f9cc3bc29 [libc++][NFC] Use std::enable_if instead of _EnableB helper in pair
This doesn't impact the compile-time efficiency, but we get better
diagnostics when an overload is disabled.
2021-09-01 10:48:09 -04:00
Louis Dionne c8b14c03ec [libc++][NFC] Fix include guard for decay_copy.h and remove underscores from the header
We don't use double underscores for private header names when they are
in a subdirectory with double underscores already.

Differential Revision: https://reviews.llvm.org/D108820
2021-08-27 12:45:53 -04:00
Louis Dionne 64184b4af0 [libc++][NFC] Remove useless _LIBCPP_PUSH_MACROS
Only files that actually use min/max are required to do this dance.

Differential Revision: https://reviews.llvm.org/D108778
2021-08-27 12:41:55 -04:00
Louis Dionne 0166690401 [libc++] Remove workarounds for the lack of deduction guides in C++17
All supported compilers have supported deduction guides in C++17 for a
while, so this isn't necessary anymore.

Differential Revision: https://reviews.llvm.org/D108213
2021-08-18 08:57:25 -04:00
Christopher Di Bella 69d5a66621 [libcxx][modularisation] splits `<utility>` into self-contained headers
* moves `std::hash` and `std::unary_function` into `__functional`
* Everything else goes into `__utility/${NAME}.h`

Differential Revision: https://reviews.llvm.org/D104002
2021-06-25 00:29:01 +00:00
Christopher Di Bella 6adbc83ee9 [libcxx][modularisation] moves <utility> content out of <type_traits>
Moves:

* `std::move`, `std::forward`, `std::declval`, and `std::swap` into
  `__utility/${FUNCTION_NAME}`.
* `std::swap_ranges` and `std::iter_swap` into
  `__algorithm/${FUNCTION_NAME}`

Differential Revision: https://reviews.llvm.org/D103734
2021-06-24 17:57:29 +00:00
Mark de Wever a354fd56c5 [libc++] Adds __utility/to_underlying.h.
During the review of D97115 it was mentioned adding the `<utility>`
header for `__to_underlying` was a bit unfortunate. Nowadays we tend to
implement smaller headers, so a good reason to move `std::to_underlying`
to its own header and adjust `<charconv>` to use the new header.

Differential Revision: https://reviews.llvm.org/D101233
2021-04-25 13:27:19 +02:00