[libc++][doc] Updates the release notes.

[Mordante]

Summary

This is a preparation for the upcoming LLVM 16 release.

[Mordante]

I've update the release notes and would like to land them before LLVM 16 is branched on July 26th.

If there are other missing features you want to mention, just add them as a review comment.

I haven't added -fexperimental-library, since these patches will update the release notes.

libcxx/docs/ReleaseNotes.rst

39

I think the experimental library is something we can add here too.

46

What will the status of ranges become?

133

Are these changes reverted too?

140

IIRC this change has been reverted. Or did we reland a new version?

[philnik]

libcxx/docs/ReleaseNotes.rst

43

Complete nit, but maybe use format library? The first thought for me was "the whole library?".

46

I think the plan is to make ranges stable.

52–75

I'd like to have some visual indicator that the text is the title of the paper. How about P1234R5 - This is a really fascinating paper?

97–98

133

Yes, the transitive includes of public headers are (almost?) a superset of the ones included in LLVM 14.

237

Use the Oxford comma consistently or don't use it at all.

[Mordante]

Thanks for the review! I'll give others some time to chime in before addressing the issues.

libcxx/docs/ReleaseNotes.rst

46

I heard the same plan ;-) but I'm not deeply involved in that part of the code so I don't know the exact status. Even less involved nowadays since we now have three people very active in ranges area :-)

52–75

I don't mind a visual indicator, but I felt the parenthesis felt odd. I expect most users will care about the title instead of the number. I'll add them in the next iteration.

133

Thanks! Then I'll remove this line.

[ldionne]

LGTM, let's please land this ASAP, I'd like to propose a slight reorganization of the sections.

libcxx/docs/ReleaseNotes.rst

46

I discussed with @var-const yesterday and we tentatively agreed that due to the branch being cut earlier than expected and to finding a few important issues (like the issue with proxy iterators pointed by @huixie90), we feel that Ranges should stay experimental in LLVM 15, as we request user feedback. Furthermore, since we now have a well defined way to enable experimental features (-fexperimental-library), users can try it out easily.

So I'd keep this as experimental in the release notes unless we change our mind.

110

140

Please don't touch this release note, I will update it when I land D126823.

[Mordante]

In D130031#3665797, @ldionne wrote:

LGTM, let's please land this ASAP, I'd like to propose a slight reorganization of the sections.

Thanks for the review. I'll land it after I address all comments.

libcxx/docs/ReleaseNotes.rst

46

Thanks for the status update!

140

A thanks! I recalled wanted to reenable them, but I couldn't find the commit.

libcxx/docs/ReleaseNotes.rst

 Note that if you are reading this file from a Git checkout or the
 main Libc++ web page, this document applies to the *next* release, not
 the current one. To see the release notes for a specific release, please
 see the `releases page <https://llvm.org/releases/>`_.
 
 What's New in Libc++ 15.0.0?
 ============================
 
+The main focus of the libc++ team has been to implement new C++20 and C++23
+features.
+
+The C++20 ``format`` library is feature complete, but not all Standard
+LWG issues have been addressed. Since it is expected that at least one of these
+issues will cause an ABI break the library is considered experimental.
+
+The C++20 ``ranges`` library has progressed a lot since the last release and is
+almost complete. The library is considered [experimental|ready for general usage].
+
+
 Implemented Papers
 ------------------
 
-- P0627R6 (Function to mark unreachable code)
-- P1165R1 (Make stateful allocator propagation more consistent for ``operator+(basic_string)``)
-- P0674R1 (Support arrays in ``make_shared`` and ``allocate_shared``)
-- P0980R1 (Making ``std::string`` constexpr)
-- P2216R3 (std::format improvements)
-- P0174R2 (Deprecating Vestigial Library Parts in C++17)
-- N4190 (Removing auto_ptr, random_shuffle(), And Old <functional> Stuff)
-- P0154R1 (Hardware inference size)
-- P0618R0 (Deprecating <codecvt>)
-- P2418R2 (Add support for ``std::generator``-like types to ``std::format``)
-- LWG3659 (Consider ``ATOMIC_FLAG_INIT`` undeprecation)
+- P0627R6 Function to mark unreachable code
+- P1165R1 Make stateful allocator propagation more consistent for ``operator+(basic_string)``
+- P0674R1 Support arrays in ``make_shared`` and ``allocate_shared``
+- P0980R1 Making ``std::string`` constexpr
+- P2216R3 std::format improvements
+- P0174R2 Deprecating Vestigial Library Parts in C++17
+- N4190 Removing ``auto_ptr``, ``random_shuffle()``, And Old ``<functional>`` Stuff
+- P0154R1 Hardware inference size
+- P0618R0 Deprecating ``<codecvt>``
+- P2418R2 Add support for ``std::generator``-like types to ``std::format``
+- LWG3659 Consider ``ATOMIC_FLAG_INIT`` undeprecation
 
 - Marked the following papers as "Complete" (note that some of those might have
   been implemented in a previous release but not marked as such):
 
-    - P1207R4 (Movability of Single-pass Iterators);
-    - P1474R1 (Helpful pointers for ``ContiguousIterator``);
-    - P1522R1 (Iterator Difference Type and Integer Overflow);
-    - P1523R1 (Views and Size Types);
-    - P1456R1 (Move-only views);
-    - P1870R1 (``forwarding-range`` is too subtle);
-    - P1878R1 (Constraining Readable Types);
-    - P1970R2 (Consistency for ``size()`` functions: Add ``ranges::ssize``);
-    - P1983R0 (Wording for GB301, US296, US292, US291, and US283).
+    - P1207R4 Movability of Single-pass Iterators
+    - P1474R1 Helpful pointers for ``ContiguousIterator``
+    - P1522R1 Iterator Difference Type and Integer Overflow
+    - P1523R1 Views and Size Types
+    - P1456R1 Move-only views
+    - P1870R1 ``forwarding-range`` is too subtle
+    - P1878R1 Constraining Readable Types
+    - P1970R2 Consistency for ``size()`` functions: Add ``ranges::ssize``
+    - P1983R0 Wording for GB301, US296, US292, US291, and US283
 
 New Features
 ------------
 
 - `pop_heap` now uses an algorithm known as "bottom-up heapsort" or
   "heapsort with bounce" to reduce the number of comparisons, and rearranges
   elements using move-assignment instead of `swap`.
 
 - Libc++ now supports a variety of assertions that can be turned on to help catch
   undefined behavior in user code. This new support is now separate from the old
   (and incomplete) Debug Mode. Vendors can select whether the library they ship
   should include assertions or not by default. For details, see
   :ref:`the documentation <assertions-mode>` about this new feature.
 
-- The implementation of the function ``std::to_chars`` for integral types has
-  moved from the dylib to the header. This means the function no longer has a
-  minimum deployment target.
+- The implementation of the function ``std::to_chars`` for integral types using
+  base 10 has moved from the dylib to the header. This means the function no
+  longer has a minimum deployment target.
+
+- The performance for ``std::to_chars``, for integral types using base 2, 8,
+  10, or 16 has been improved.
+
+- The functions ``std::from_chars`` and ``std::to_chars`` got 128-bit integral
+  support.
 
 - The format functions (``std::format``, ``std::format_to``, ``std::format_to_n``, and
   ``std::formatted_size``) now validate the format string at compile time.
   When the format string is invalid this will make the code ill-formed instead
   of throwing an exception at run-time.  (This does not affect the ``v``
   functions.)
 
 - All format functions in ``<format>`` allow the usage of non-copyable types as
   argument for the formatting functions. This change causes bit fields to become
   invalid arguments for the formatting functions.
 
+- ``boyer_moore_searcher`` and ``boyer_moore_horspool_searcher`` have been implemented.
+
 API Changes
 -----------
 
 - The ``_LIBCPP_ABI_UNSTABLE`` macro has been removed in favour of setting
   ``_LIBCPP_ABI_VERSION=2``. This should not have any impact on users because
   they were not supposed to set ``_LIBCPP_ABI_UNSTABLE`` manually, however we
   still feel that it is worth mentioning in the release notes in case some users
   had been doing it.
 
 - The header ``<experimental/filesystem>`` has been removed. Instead, use
   ``<filesystem>`` header. The associated macro
-  ``_LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM`` has also been removed.
+  ``_LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM`` has been removed too.
 
 - Libc++ is getting ready to remove unnecessary transitive inclusions. This may
   break your code in the future. To future-proof your code to these removals,
   please compile your code with ``_LIBCPP_REMOVE_TRANSITIVE_INCLUDES`` defined
   and fix any compilation error resulting from missing includes.
 
 - The ``<algorithm>``, ``<array>``, ``<optional>``, ``<unordered_map>`` and ``<vector>``
   headers no longer transitively include the ``<functional>`` header. If you see compiler
   errors related to missing declarations in namespace ``std``, make sure you have the
   necessary includes.
 
 - The integer distributions ``binomial_distribution``, ``discrete_distribution``,
   ``geometric_distribution``, ``negative_binomial_distribution``, ``poisson_distribution``,
   and ``uniform_int_distribution`` now conform to the Standard by rejecting
   template parameter types other than ``short``, ``int``, ``long``, ``long long``,
   (as an extension) ``__int128_t``, and the unsigned versions thereof.
   In particular, ``uniform_int_distribution<int8_t>`` is no longer supported.
 
 - The C++14 function ``std::quoted(const char*)`` is no longer supported in
   C++03 or C++11 modes.
 
 - Setting a custom debug handler with ``std::__libcpp_debug_function`` is not
   supported anymore. Please migrate to using the new support for
   :ref:`assertions <assertions-mode>` instead.
 
 - ``vector<bool>::const_reference``, ``vector<bool>::const_iterator::reference``
   and ``bitset::const_reference`` are now aliases for `bool` in the unstable ABI.
 
 - The ``_LIBCPP_DEBUG`` macro is not supported anymore. It will be honoured until
   LLVM 16, and then it will be an error to define that macro. To enable basic
   assertions (previously ``_LIBCPP_DEBUG=0``), please use ``_LIBCPP_ENABLE_ASSERTIONS=1``.
   To enable the debug mode (previously ``_LIBCPP_DEBUG=1|2``), please ensure that
   the library has been built with support for the debug mode, and it will be
   enabled automatically (no need to define ``_LIBCPP_DEBUG``).
 
 - The ``_LIBCPP_DISABLE_EXTERN_TEMPLATE`` macro is not honored anymore when defined by
   users of libc++. Instead, users not wishing to take a dependency on libc++ should link
   against the static version of libc++, which will result in no dependency being
   taken against the shared library.
 
 - The ``_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION`` macro has been added to allow
-  re-enabling the ``allocator<void>`` specialization. When used in conjuction with
+  re-enabling the ``allocator<void>`` specialization. When used in conjunction with
   ``_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS``, this ensures that the members of
   ``allocator<void>`` removed in C++20 can be accessed.
 
 - The experimental versions of ``boyer_moore_searcher`` and ``boyer_moore_horspool_searcher``
   will be removed in LLVM 17. You can disable the deprecation warnings by defining
   ``_LIBCPP_NO_EXPERIMENTAL_DEPRECATION_WARNING_SEARCHERS``.
 
 - ``std::function`` has been removed in C++03. If you are using it, please remove usages

 - Previously, the C++ ABI library headers would be installed inside ``<prefix>/include/c++/v1``
   alongside the libc++ headers as part of building libc++. This is not the case anymore -- the
   ABI library is expected to install its headers where it wants them as part of its own build.
   Note that no action is required for most users, who build libc++ against libc++abi, since
   libc++abi already installs its headers in the right location. However, vendors building
   libc++ against alternate ABI libraries should make sure that their ABI library installs
   its own headers.
 
-- The legacy testing configuration is now deprecated and will be removed in the next release. For
+- The legacy testing configuration is now deprecated and will be removed in LLVM 16. For
   most users, this should not have any impact. However, if you are testing libc++, libc++abi or
   libunwind in a configuration or on a platform that used to be supported by the legacy testing
   configuration and isn't supported by one of the configurations in ``libcxx/test/configs``,
-  ``libcxxabi/test/configs`` or ``libunwind/test/configs``, please move to one of those
+  ``libcxxabi/test/configs``, or ``libunwind/test/configs``, please move to one of those
   configurations or define your own.
 
 - The ``LIBCXX_ENABLE_DEBUG_MODE_SUPPORT`` CMake configuration is not supported anymore. If you
   were disabling support for the debug mode with that flag, please use ``LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS=OFF``
   instead.
 
 - MinGW DLL builds of libc++ no longer use dllimport in their headers, which
   means that the same set of installed headers works for both DLL and static
   linkage. This means that distributors finally can build both library
   versions with a single CMake invocation.
 
 - The ``LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT`` configuration option has been removed. Indeed,
   the risk of ODR violations from mixing different versions of libc++ in the same program has
   been mitigated with a different technique that is simpler and does not have the drawbacks of
   using internal linkage.