[libc++][C++03] Use `__cxx03/` headers in C++03 mode (#109002)

This patch implements the forwarding to frozen C++03 headers as
discussed in
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-

[libc++][C++03] Use `__cxx03/` headers in C++03 mode (#109002)

This patch implements the forwarding to frozen C++03 headers as
discussed in
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc. In the
RFC, we initially proposed selecting the right headers from the Clang
driver, however consensus seemed to steer towards handling this in the
library itself. This patch implements that direction.

At a high level, the changes basically amount to making each public
header look like this:

```
// inside <vector>
#ifdef _LIBCPP_CXX03_LANG
# include <__cxx03/vector>
#else
// normal <vector> content
#endif
```

In most cases, public headers are simple umbrella headers so there isn't
much code in the #else branch. In other cases, the #else branch contains
the actual implementation of the header.

show more ...

[libc++] Add #if 0 block to all the top-level headers (#119234)

Including The frozen C++03 headers results in a lot of formatting
changes in the main headers, so this splits these changes into a
sep

[libc++] Add #if 0 block to all the top-level headers (#119234)

Including The frozen C++03 headers results in a lot of formatting
changes in the main headers, so this splits these changes into a
separate commit instead.

This is part of
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc.

show more ...

[libc++] Granularize <cstddef> includes (#108696)

[libc++] Include the rest of the detail headers by version in the umbrella headers (#96032)

This is a follow-up to #83740.

[libc++][tuple][utility] P2968R2: Make `std::ignore` a first-class object (#97401)

Implements: https://wg21.link/P2968R2

References:
- https://eel.is/c++draft/tuple.general
- https://eel.is/c+

[libc++][tuple][utility] P2968R2: Make `std::ignore` a first-class object (#97401)

Implements: https://wg21.link/P2968R2

References:
- https://eel.is/c++draft/tuple.general
- https://eel.is/c++draft/tuple.syn
- https://eel.is/c++draft/tuple.creation
- https://github.com/cplusplus/draft/milestone/31
- https://github.com/cplusplus/draft/pull/7109
- https://github.com/cplusplus/papers/issues/1640
- https://cplusplus.github.io/LWG/issue2933
- https://cplusplus.github.io/LWG/issue3978

---------

Co-authored-by: Hristo Hristov <zingam@outlook.com>

show more ...

[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
th

[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

show more ...

[libc++] P2770R0: Stashing stashing iterators for proper flattening (#66033)

- Partially implements P2770R0 (http://wg21.link/p2770)
- Fixes https://wg21.link/LWG3698, https://wg21.link/LWG3700, an

[libc++] P2770R0: Stashing stashing iterators for proper flattening (#66033)

- Partially implements P2770R0 (http://wg21.link/p2770)
- Fixes https://wg21.link/LWG3698, https://wg21.link/LWG3700, and https://wg21.link/LWG3791
- join_with_view hasn't been done yet since this type isn't implemented yet
- Rename tuple test directory to match the standard (which changed in P2770R0)
- Rename join_view test directory to match the standard

show more ...

[libc++] Updates C++2b to C++23.

During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.

This updates the reference to c++2b to c++23 and updat

[libc++] Updates C++2b to C++23.

During the ISO C++ Committee meeting plenary session the C++23 Standard
has been voted as technical complete.

This updates the reference to c++2b to c++23 and updates the __cplusplus
macro.

Note since we use clang-tidy 16 a small work-around is needed. Clang
knows -std=c++23 but clang-tidy not so for now force the lit compiler
flag to use -std=c++2b instead of -std=c++23.

Reviewed By: #libc, philnik, jloser, ldionne

Differential Revision: https://reviews.llvm.org/D150795

show more ...

[libc++] Clean up pair's constructors and assignment operators

This patch makes std::pair's constructors and assignment operators
closer to conforming in C++23. The only missing bit I am aware of
no

[libc++] Clean up pair's constructors and assignment operators

This patch makes std::pair's constructors and assignment operators
closer to conforming in C++23. The only missing bit I am aware of
now is `reference_constructs_from_temporary_v` checks, which we
don't have the tools for yet.

This patch also refactors a long-standing non-standard extension where
we'd provide constructors for tuple-like types in all standard modes. The
criteria for being a tuple-like type are different from pair-like types
as introduced recently in the standard, leading to a lot of complexity
when trying to implement recent papers that touch the pair constructors.

After this patch, the pre-C++23 extension is provided in a self-contained
block so that we can easily deprecate and eventually remove the extension
in future releases.

Differential Revision: https://reviews.llvm.org/D143914

show more ...

[libc++] Rename __tuple_dir back to __tuple

This essentially reverts D139270

Reviewed By: #libc, EricWF

Spies: tahonermann, libcxx-commits, arichardson

Differential Revision: https://reviews.llvm

[libc++] Rename __tuple_dir back to __tuple

This essentially reverts D139270

Reviewed By: #libc, EricWF

Spies: tahonermann, libcxx-commits, arichardson

Differential Revision: https://reviews.llvm.org/D147519

show more ...

[libc++][ranges] Implement LWG-3865 Sorting a range of pairs

Reviewed By: Mordante, philnik, ldionne, #libc

Differential Revision: https://reviews.llvm.org/D144262

[libc++] Improves clang-format settings.

Add a new test based .clang-format file which inherits from the generic
one. This moves some test specific formatting rules to the test
directory.

The main

[libc++] Improves clang-format settings.

Add a new test based .clang-format file which inherits from the generic
one. This moves some test specific formatting rules to the test
directory.

The main benefit is that headers are sorted, which makes it more likely
to catch these errors before creating a review instead of spotting the
error in the CI clang-tidy step.

Reviewed By: ldionne, philnik, #libc

Differential Revision: https://reviews.llvm.org/D144755

show more ...

[libc++] Improve binary size when using __transaction

__exception_guard is a no-op in -fno-exceptions mode to produce better code-gen. This means that we don't provide the strong exception guarantee

[libc++] Improve binary size when using __transaction

__exception_guard is a no-op in -fno-exceptions mode to produce better code-gen. This means that we don't provide the strong exception guarantees. However, Clang doesn't generate cleanup code with exceptions disabled, so even if we wanted to provide the strong exception guarantees we couldn't. This is also only relevant for constructs with a stack of -fexceptions > -fno-exceptions > -fexceptions code, since the exception can't be caught where exceptions are disabled. While -fexceptions > -fno-exceptions is quite common (e.g. libc++.dylib > -fno-exceptions), having another layer with exceptions enabled seems a lot less common, especially one that tries to catch an exception through -fno-exceptions code.

Fixes https://github.com/llvm/llvm-project/issues/56783

Reviewed By: ldionne, Mordante, huixie90, #libc

Spies: EricWF, alexfh, hans, joanahalili, libcxx-commits

Differential Revision: https://reviews.llvm.org/D133661

show more ...

[libc++] Improve the implementation of std::unreachable

First, use __builtin_unreachable unconditionally. It is implemented by
all the compilers that we support. Clang started supporting it around
C

[libc++] Improve the implementation of std::unreachable

First, use __builtin_unreachable unconditionally. It is implemented by
all the compilers that we support. Clang started supporting it around
Clang 4, and GCC around GCC 4.10.

Also add _LIBCPP_ASSERT so that we will actually get a guaranteed crash
if we reached `std::unreachable()` and assertions have been enabled,
since that's UB that's extremely easy to catch.

Differential Revision: https://reviews.llvm.org/D131620

show more ...

[libc++] Granularize <type_traits> includes in <utility>

Reviewed By: Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D140426

[libc++] Rename __tuple to __tuple_dir to avoid file collision

Rename the `__tuple` directory in libc++ headers to `__tuple_dir`
to avoid file collision when installing. Historically, `__tuple` has

[libc++] Rename __tuple to __tuple_dir to avoid file collision

Rename the `__tuple` directory in libc++ headers to `__tuple_dir`
to avoid file collision when installing. Historically, `__tuple` has
been a file and it has been replaced by a directory
in 2d52c6bfae801b016dd3627b8c0e7c4a99405549. Replacing a regular file
with a directory (or more importantly, the other way around when
downgrading) is not universally supported. Since this is an internal
header, its actual name should not matter, so just rename it to avoid
problems.

Differential Revision: https://reviews.llvm.org/D139270

show more ...

[libc++] implement "pair" section of P2321R2 `zip`

Differential Revision: https://reviews.llvm.org/D131495

[libc++] Granularize __tuple

Reviewed By: ldionne, #libc

Spies: libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D133081

[NFC][libc++] Moves transitive includes location.

As discussed in D132284 they will be moved to the end.

Reviewed By: #libc, Mordante

Differential Revision: https://reviews.llvm.org/D133212

[libc++] Implement P2445R1 (`std::forward_like`)

Co-authored-by: A. Jiang <de34@live.cn>

Reviewed By: philnik, huixie90, #libc

Differential Revision: https://reviews.llvm.org/D132327

[libc++] Reduces the number of transitive includes.

This defines a new policy for removal of transitive includes.
The goal of the policy it to make it relatively easy to remove
headers when needed,

[libc++] Reduces the number of transitive includes.

This defines a new policy for removal of transitive includes.
The goal of the policy it to make it relatively easy to remove
headers when needed, but avoid breaking developers using and
vendors shipping libc++.

The method used is to guard transitive includes based on the
C++ language version. For the upcoming C++23 we can remove
headers when we want, but for other language versions we try
to keep it to a minimum.

In this code the transitive include of `<chrono>` is removed
since D128577 introduces a header cycle between `<format>`
and `<chrono>`. This cycle is indirectly required by the
Standard. Our cycle dependency tool basically is a grep based
tool, so it needs some hints to ignore cycles. With the input
of our transitive include tests we can create a better tool.
However that's out of the scope of this patch.

Note the flag `_LIBCPP_REMOVE_TRANSITIVE_INCLUDES` remains
unchanged. So users can still opt-out of transitives includes
entirely.

Reviewed By: #libc, ldionne, philnik

Differential Revision: https://reviews.llvm.org/D132284

show more ...

[libc++] Re-add transitive includes that had been removed since LLVM 14

This commit re-adds transitive includes that had been removed by
4cd04d1687f1, c36870c8e79c, a83f4b9cda57, 1458458b558d, 2e2f3

[libc++] Re-add transitive includes that had been removed since LLVM 14

This commit re-adds transitive includes that had been removed by
4cd04d1687f1, c36870c8e79c, a83f4b9cda57, 1458458b558d, 2e2f3158c604,
and 489637e66dd3. This should cover almost all the includes that had
been removed since LLVM 14 and that would contribute to breaking user
code when releasing LLVM 15.

It is possible to disable the inclusion of these headers by defining
_LIBCPP_REMOVE_TRANSITIVE_INCLUDES. The intent is that vendors will
enable that macro and start fixing downstream issues immediately. We
can then remove the macro (and the transitive includes) by default in
a future release. That way, we will break users only once by removing
transitive includes in bulk instead of doing it bit by bit a every
release, which is more disruptive for users.

Note 1: The set of headers to re-add was found by re-generating the
transitive include test on a checkout of release/14.x, which
provided the list of all transitive includes we used to provide.

Note 2: Several includes of <vector>, <optional>, <array> and <unordered_map>
have been added in this commit. These transitive inclusions were
added when we implemented boyer_moore_searcher in <functional>.

Note 3: This is a best effort patch to try and resolve downstream breakage
caused since branching LLVM 14. I wasn't able to perfectly mirror
transitive includes in LLVM 14 for a few headers, so I added a
release note explaining it. To summarize, adding boyer_moore_searcher
created a bunch of circular dependencies, so we have to break
backwards compatibility in a few cases.

Differential Revision: https://reviews.llvm.org/D128661

show more ...

[libc++] Mark standard-mandated includes as such

Reviewed By: ldionne, Mordante, #libc, saugustine

Spies: saugustine, MaskRay, arichardson, mstorsjo, jloser, libcxx-commits, arphaman

Differential

[libc++] Mark standard-mandated includes as such

Reviewed By: ldionne, Mordante, #libc, saugustine

Spies: saugustine, MaskRay, arichardson, mstorsjo, jloser, libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D127953

show more ...

[libc++] Granularize even more of type_traits

Reviewed By: ldionne, #libc

Spies: libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D126593

[libc++] Ensure that all public C++ headers include <__assert>

This patch changes the requirement for getting the declaration of the
assertion handler from including <__assert> to including any publ

[libc++] Ensure that all public C++ headers include <__assert>

This patch changes the requirement for getting the declaration of the
assertion handler from including <__assert> to including any public
C++ header of the library. Note that C compatibility headers are
excluded because we don't implement all the C headers ourselves --
some of them are taken straight from the C library, like assert.h.

It also adds a generated test to check it. Furthermore, this new
generated test is designed in a way that will make it possible to
replace almost all the existing test-generation scripts with this
system in upcoming patches.

Differential Revision: https://reviews.llvm.org/D122506

show more ...