Bump the trunk major version to 13

====================================================

Extra Clang Tools 12.0.0 (In-Progress) Release Notes

Extra Clang Tools 13.0.0 (In-Progress) Release Notes

====================================================

.. contents::

.. warning::

   These are in-progress notes for the upcoming Extra Clang Tools 12 release.

   These are in-progress notes for the upcoming Extra Clang Tools 13 release.

   Release notes for previous releases can be found on

   `the Download Page <https://releases.llvm.org/download.html>`_.

============

This document contains the release notes for the Extra Clang Tools, part of the

Clang release 12.0.0. Here we describe the status of the Extra Clang Tools in

Clang release 13.0.0. Here we describe the status of the Extra Clang Tools in

some detail, including major improvements from the previous release and new

feature work. All LLVM releases may be downloaded from the `LLVM releases web

site <https://llvm.org/releases/>`_.

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 Extra Clang Tools 12.0.0?

What's New in Extra Clang Tools 13.0.0?

=======================================

Some of the major new features and improvements to Extra Clang Tools are listed

Improvements to clangd

----------------------

- clangd's memory usage is significantly reduced on most Linux systems.

  In particular, memory usage should not increase dramatically over time.

  The standard allocator on most systems is glibc's ptmalloc2, and it creates

  disproportionately large heaps when handling clangd's allocation patterns.

  By default, clangd will now periodically call ``malloc_trim`` to release free

  pages on glibc systems.

  Users of other allocators (such as ``jemalloc`` or ``tcmalloc``) on glibc

  systems can disable this using ``--malloc_trim=0`` or the CMake flag

  ``-DCLANGD_MALLOC_TRIM=0``.

The improvements are...

Improvements to clang-doc

-------------------------

Improvements to clang-query

---------------------------

- The IgnoreImplicitCastsAndParentheses traversal mode has been removed.

The improvements are...

Improvements to clang-rename

----------------------------

Improvements to clang-tidy

--------------------------

- Checks that allow configuring names of headers to include now support wrapping

  the include in angle brackets to create a system include. For example,

  :doc:`cppcoreguidelines-init-variables

  <clang-tidy/checks/cppcoreguidelines-init-variables>` and

  :doc:`modernize-make-unique <clang-tidy/checks/modernize-make-unique>`.

- CheckOptions that take boolean values now support all spellings supported in 

  the `YAML format <https://yaml.org/type/bool.html>`_.

New modules

^^^^^^^^^^^

- New ``altera`` module.

  Includes checks related to OpenCL for FPGA coding guidelines, based on the

  `Altera SDK for OpenCL: Best Practices Guide

  <https://www.altera.com/en_US/pdfs/literature/hb/opencl-sdk/aocl_optimization_guide.pdf>`_.

- New ``concurrency`` module.

  Includes checks related to concurrent programming (e.g. threads, fibers,

  coroutines, etc.).

New checks

^^^^^^^^^^

- New :doc:`altera-kernel-name-restriction

  <clang-tidy/checks/altera-kernel-name-restriction>` check.

  Finds kernel files and include directives whose filename is `kernel.cl`,

  `Verilog.cl`, or `VHDL.cl`.

- New :doc:`altera-single-work-item-barrier

  <clang-tidy/checks/altera-single-work-item-barrier>` check.

  Finds OpenCL kernel functions that call a barrier function but do not call

  an ID function.

- New :doc:`altera-struct-pack-align

  <clang-tidy/checks/altera-struct-pack-align>` check.

  Finds structs that are inefficiently packed or aligned, and recommends

  packing and/or aligning of said structs as needed.

- New :doc:`cppcoreguidelines-prefer-member-initializer

  <clang-tidy/checks/cppcoreguidelines-prefer-member-initializer>` check.

  Finds member initializations in the constructor body which can be placed into

  the initialization list instead.

- New :doc:`bugprone-misplaced-pointer-arithmetic-in-alloc

  <clang-tidy/checks/bugprone-misplaced-pointer-arithmetic-in-alloc>` check.

- New :doc:`bugprone-redundant-branch-condition

  <clang-tidy/checks/bugprone-redundant-branch-condition>` check.

  Finds condition variables in nested ``if`` statements that were also checked

  in the outer ``if`` statement and were not changed.

- New :doc:`concurrency-mt-unsafe <clang-tidy/checks/concurrency-mt-unsafe>`

  check.

  Finds thread-unsafe functions usage. Currently knows about POSIX and

  Glibc function sets.

- New :doc:`bugprone-signal-handler

  <clang-tidy/checks/bugprone-signal-handler>` check.

  Finds functions registered as signal handlers that call non asynchronous-safe

  functions.

- New :doc:`cert-sig30-c

  <clang-tidy/checks/cert-sig30-c>` check.

  Alias to the :doc:`bugprone-signal-handler

  <clang-tidy/checks/bugprone-signal-handler>` check.

- New :doc:`performance-no-int-to-ptr

  <clang-tidy/checks/performance-no-int-to-ptr>` check.

  Diagnoses every integer to pointer cast.

- New :doc:`readability-function-cognitive-complexity

  <clang-tidy/checks/readability-function-cognitive-complexity>` check.

  Flags functions with Cognitive Complexity metric exceeding the configured limit.

Changes in existing checks

^^^^^^^^^^^^^^^^^^^^^^^^^^

- Improved :doc:`modernize-loop-convert

  <clang-tidy/checks/modernize-loop-convert>` check.

  Now able to transform iterator loops using ``rbegin`` and ``rend`` methods.

- Improved :doc:`readability-identifier-naming

  <clang-tidy/checks/readability-identifier-naming>` check.

  Added an option `GetConfigPerFile` to support including files which use

  different naming styles.

  Now renames overridden virtual methods if the method they override has a

  style violation.

  Added support for specifying the style of scoped ``enum`` constants. If 

  unspecified, will fall back to the style for regular ``enum`` constants.

  Added an option `IgnoredRegexp` per identifier type to suppress identifier

  naming checks for names matching a regular expression.

- Removed `google-runtime-references` check because the rule it checks does

  not exist in the Google Style Guide anymore.

- Improved :doc:`readability-redundant-string-init

  <clang-tidy/checks/readability-redundant-string-init>` check.

  Added `std::basic_string_view` to default list of ``string``-like types.

The improvements are...

Improvements to include-fixer

-----------------------------

# built documents.

#

# The short version.

version = '12'

version = '13'

# The full version, including alpha/beta/rc tags.

release = '12'

release = '13'

# The language for content autogenerated by Sphinx. Refer to documentation

# for a list of supported languages.

========================================

Clang 12.0.0 (In-Progress) Release Notes

Clang 13.0.0 (In-Progress) Release Notes

========================================

.. contents::

.. warning::

   These are in-progress notes for the upcoming Clang 12 release.

   These are in-progress notes for the upcoming Clang 13 release.

   Release notes for previous releases can be found on

   `the Download Page <https://releases.llvm.org/download.html>`_.

============

This document contains the release notes for the Clang C/C++/Objective-C

frontend, part of the LLVM Compiler Infrastructure, release 12.0.0. Here we

frontend, part of the LLVM Compiler Infrastructure, release 13.0.0. Here we

describe the status of Clang in some detail, including major

improvements from the previous release and new feature work. For the

general LLVM release notes, see `the LLVM

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 Clang 12.0.0?

What's New in Clang 13.0.0?

===========================

Some of the major new features and improvements to Clang are listed

Non-comprehensive list of changes in this release

-------------------------------------------------

- The builtin intrinsics ``__builtin_bitreverse8``, ``__builtin_bitreverse16``,

  ``__builtin_bitreverse32`` and ``__builtin_bitreverse64`` may now be used

  within constant expressions.

- The builtin intrinsics ``__builtin_rotateleft8``, ``__builtin_rotateleft16``,

  ``__builtin_rotateleft32`` and ``__builtin_rotateleft64`` may now be used

  within constant expressions.

- The builtin intrinsics ``__builtin_rotateright8``, ``__builtin_rotateright16``,

  ``__builtin_rotateright32`` and ``__builtin_rotateright64`` may now be used

  within constant expressions.

- ...

New Compiler Flags

------------------

- ...

- -fpch-codegen and -fpch-debuginfo generate shared code and/or debuginfo

  for contents of a precompiled header in a separate object file. This object

  file needs to be linked in, but its contents do not need to be generated

  for other objects using the precompiled header. This should usually save

  compile time. If not using clang-cl, the separate object file needs to

  be created explicitly from the precompiled header.

  Example of use:

  .. code-block:: console

    $ clang++ -x c++-header header.h -o header.pch -fpch-codegen -fpch-debuginfo

    $ clang++ -c header.pch -o shared.o

    $ clang++ -c source.cpp -o source.o -include-pch header.pch

    $ clang++ -o binary source.o shared.o

  - Using -fpch-instantiate-templates when generating the precompiled header

    usually increases the amount of code/debuginfo that can be shared.

  - In some cases, especially when building with optimizations enabled, using

    -fpch-codegen may generate so much code in the shared object that compiling

    it may be a net loss in build time.

  - Since headers may bring in private symbols of other libraries, it may be

    sometimes necessary to discard unused symbols (such as by adding

    -Wl,--gc-sections on ELF platforms to the linking command, and possibly

    adding -fdata-sections -ffunction-sections to the command generating

    the shared object).

- New option ``-fbinutils-version=`` specifies the targeted binutils version.

  For example, ``-fbinutils-version=2.35`` means compatibility with GNU as/ld

  before 2.35 is not needed: new features can be used and there is no need to

  work around old GNU as/ld bugs.

Deprecated Compiler Flags

-------------------------

The following options are deprecated and ignored. They will be removed in

future versions of Clang.

- ...

Modified Compiler Flags

-----------------------

- On ELF, ``-gz`` now defaults to ``-gz=zlib`` with the integrated assembler.

  It produces ``SHF_COMPRESSED`` style compression of debug information. GNU

  binutils 2.26 or newer, or lld is required to link produced object files. Use

  ``-gz=zlib-gnu`` to get the old behavior.

- Now that `this` pointers are tagged with `nonnull` and `dereferenceable(N)`,

  `-fno-delete-null-pointer-checks` has gained the power to remove the

  `nonnull` attribute on `this` for configurations that need it to be nullable.

- ``-gsplit-dwarf`` no longer implies ``-g2``.

- ``-fasynchronous-unwind-tables`` is now the default on Linux AArch64/PowerPC.

  This behavior matches newer GCC.

  (`D91760 <https://reviews.llvm.org/D91760>`_)

  (`D92054 <https://reviews.llvm.org/D92054>`_)

- ...

Removed Compiler Flags

-------------------------

The following options no longer exist.

- clang-cl's ``/Zd`` flag no longer exist. But ``-gline-tables-only`` still

  exists and does the same thing.

- ...

New Pragmas in Clang

--------------------

Attribute Changes in Clang

--------------------------

- Added support for the C++20 likelihood attributes ``[[likely]]`` and

  ``[[unlikely]]``. As an extension they can be used in C++11 and newer.

  This extension is enabled by default.

- ...

Windows Support

---------------

X86 Support in Clang

--------------------

- The x86 intrinsics ``_mm_popcnt_u32``, ``_mm_popcnt_u64``, ``_popcnt32``,

  ``_popcnt64``, ``__popcntd`` and ``__popcntq``  may now be used within

  constant expressions.

- The x86 intrinsics ``_bit_scan_forward``, ``__bsfd`` and ``__bsfq`` may now

  be used within constant expressions.

- The x86 intrinsics ``_bit_scan_reverse``, ``__bsrd`` and ``__bsrq`` may now

  be used within constant expressions.

- The x86 intrinsics ``__bswap``, ``__bswapd``, ``__bswap64`` and ``__bswapq``

  may now be used within constant expressions.

- The x86 intrinsics ``_castf32_u32``, ``_castf64_u64``, ``_castu32_f32`` and

  ``_castu64_f64`` may now be used within constant expressions.

- The x86 intrinsics ``__rolb``, ``__rolw``, ``__rold``, ``__rolq`, ``_rotl``,

  ``_rotwl`` and ``_lrotl`` may now be used within constant expressions.

- The x86 intrinsics ``__rorb``, ``__rorw``, ``__rord``, ``__rorq`, ``_rotr``,

  ``_rotwr`` and ``_lrotr`` may now be used within constant expressions.

- Support for ``-march=alderlake``, ``-march=sapphirerapids`` and

  ``-march=znver3`` was added.

- Support for ``-march=x86-64-v[234]`` has been added.

  See :doc:`UsersManual` for details about these micro-architecture levels.

- The -mtune command line option is no longer ignored for X86. This can be used

  to request microarchitectural optimizations independent on -march. -march=<cpu>

  implies -mtune=<cpu>. -mtune=generic is the default with no -march or -mtune

  specified.

- Support for ``HRESET`` instructions has been added.

- Support for ``UINTR`` instructions has been added.

- Support for ``AVXVNNI`` instructions has been added.

- ...

Internal API Changes

--------------------

These are major API changes that have happened since the 11.0.0 release of

These are major API changes that have happened since the 12.0.0 release of

Clang. If upgrading an external codebase that uses Clang as a library,

this section should help get you past the largest hurdles of upgrading.

Build System Changes

--------------------

These are major changes to the build system that have happened since the 11.0.0

These are major changes to the build system that have happened since the 12.0.0

release of Clang. Users of the build system should adjust accordingly.

- ...

AST Matchers

------------

- The behavior of TK_IgnoreUnlessSpelledInSource with the traverse() matcher

  has been changed to no longer match on template instantiations or on

  implicit nodes which are not spelled in the source.

- The TK_IgnoreImplicitCastsAndParentheses traversal kind was removed. It

  is recommended to use TK_IgnoreUnlessSpelledInSource instead.

- The behavior of the forEach() matcher was changed to not internally ignore

  implicit and parenthesis nodes.

- ...

clang-format

------------

- Option ``BitFieldColonSpacing`` has been added that decides how

  space should be added around identifier, colon and bit-width in

  bitfield definitions.

  .. code-block:: c++

    // Both (default)

    struct F {

      unsigned dscp : 6;

      unsigned ecn  : 2; // AlignConsecutiveBitFields=true

    };

    // None

    struct F {

      unsigned dscp:6;

      unsigned ecn :2;

    };

    // Before

    struct F {

      unsigned dscp :6;

      unsigned ecn  :2;

    };

    // After

    struct F {

      unsigned dscp: 6;

      unsigned ecn : 2;

    };

- Experimental Support in clang-format for concepts has been improved, to

  aid this the follow options have been added

- Option ``IndentRequires`` has been added to indent the ``requires`` keyword

  in templates.

- Option ``BreakBeforeConceptDeclarations`` has been added to aid the formatting of concepts.

- Option ``IndentPragmas`` has been added to allow #pragma to indented with the current scope

  level. This is especially useful when using #pragma to mark OpenMP sections of code.

- Option ``SpaceBeforeCaseColon`` has been added to add a space before the

  colon in a case or default statement.

- Option ``StatementAttributeLikeMacros`` has been added to declare

  macros which are not parsed as a type in front of a statement. See

  the documentation for an example.

- Options ``AlignConsecutiveAssignments``, ``AlignConsecutiveBitFields``,

  ``AlignConsecutiveDeclarations`` and ``AlignConsecutiveMacros`` have been modified to allow

  alignment across empty lines and/or comments.

- ...

libclang

--------

# built documents.

#

# The short version.

version = '12'

version = '13'

# The full version, including alpha/beta/rc tags.

release = '12'

release = '13'

# The language for content autogenerated by Sphinx. Refer to documentation

# for a list of supported languages.

  project(libcxx CXX C)

  set(PACKAGE_NAME libcxx)

  set(PACKAGE_VERSION 12.0.0git)

  set(PACKAGE_VERSION 13.0.0git)

  set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")

  set(PACKAGE_BUGREPORT "llvm-bugs@lists.llvm.org")