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========================================
Clang 13.0.0 (In-Progress) Release Notes
========================================
.. contents::
:local:
:depth: 2
Written by the `LLVM Team <https://llvm.org/>`_
.. warning::
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>`_.
Introduction
============
This document contains the release notes for the Clang C/C++/Objective-C
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
documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM
releases may be downloaded from the `LLVM releases web
site <https://llvm.org/releases/>`_.
For more information about Clang or LLVM, including information about the
latest release, please see the `Clang Web Site <https://clang.llvm.org>`_ or the
`LLVM Web Site <https://llvm.org>`_.
Note that if you are reading this file from a Git checkout or the
main Clang 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 Clang 13.0.0?
===========================
Some of the major new features and improvements to Clang are listed
here. Generic improvements to Clang as a whole or to its underlying
infrastructure are described first, followed by language-specific
sections with improvements to Clang's support for those languages.
Major New Features
------------------
- ...
Improvements to Clang's diagnostics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- ...
Non-comprehensive list of changes in this release
-------------------------------------------------
- ...
New Compiler Flags
------------------
- ...
Deprecated Compiler Flags
-------------------------
- ...
Modified Compiler Flags
-----------------------
- -Wshadow now also checks for shadowed structured bindings
- ``-B <prefix>`` (when ``<prefix>`` is a directory) was overloaded to additionally
detect GCC installations under ``<prefix>`` (``lib{,32,64}/gcc{,-cross}/$triple``).
This behavior was incompatible with GCC, caused interop issues with
``--gcc-toolchain``, and was thus dropped. Specify ``--gcc-toolchain=<dir>``
instead. ``-B``'s other GCC-compatible semantics are preserved:
``$prefix/$triple-$file`` and ``$prefix$file`` are searched for executables,
libraries, includes, and data files used by the compiler.
Removed Compiler Flags
-------------------------
- The clang-cl ``/fallback`` flag, which made clang-cl invoke Microsoft Visual
C++ on files it couldn't compile itself, has been removed.
- ``-Wreturn-std-move-in-c++11``, which checked whether an entity is affected by
`CWG1579 <https://wg21.link/CWG1579>`_ to become implicitly movable, has been
removed.
New Pragmas in Clang
--------------------
- ...
Attribute Changes in Clang
--------------------------
- ...
Windows Support
---------------
C Language Changes in Clang
---------------------------
- ...
C++ Language Changes in Clang
-----------------------------
- ...
C++1z Feature Support
^^^^^^^^^^^^^^^^^^^^^
...
Objective-C Language Changes in Clang
-------------------------------------
OpenCL C Language Changes in Clang
----------------------------------
...
ABI Changes in Clang
--------------------
OpenMP Support in Clang
-----------------------
- ...
CUDA Support in Clang
---------------------
- ...
X86 Support in Clang
--------------------
- ...
Internal API Changes
--------------------
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.
- ...
Removed a RecursiveASTVisitor feature to visit operator kinds with different methods Summary: This feature was only used in two places, but contributed a non-trivial amount to the complexity of RecursiveASTVisitor, and was buggy (see my recent patches where I was fixing the bugs that I noticed). I don't think the convenience benefit of this feature is worth the complexity. Besides complexity, another issue with the current state of RecursiveASTVisitor is the non-uniformity in how it handles different AST nodes. All AST nodes follow a regular pattern, but operators are special -- and this special behavior not documented. Correct usage of RecursiveASTVisitor relies on shadowing member functions with specific names and signatures. Near misses don't cause any compile-time errors, incorrectly named or typed methods are just silently ignored. Therefore, predictability of RecursiveASTVisitor API is quite important. This change reduces the size of the `clang` binary by 38 KB (0.2%) in release mode, and by 7 MB (0.3%) in debug mode. The `clang-tidy` binary is reduced by 205 KB (0.3%) in release mode, and by 5 MB (0.4%) in debug mode. I don't think these code size improvements are significant enough to justify this change on its own (for me, the primary motivation is reducing code complexity), but they I think are a nice side-effect. Reviewers: rsmith, sammccall, ymandel, aaron.ballman Reviewed By: rsmith, sammccall, ymandel, aaron.ballman Subscribers: cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D82921
2020-07-03 23:01:01 +08:00
Build System Changes
--------------------
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.
- The option ``LIBCLANG_INCLUDE_CLANG_TOOLS_EXTRA`` no longer exists. There were
two releases with that flag forced off, and no uses were added that forced it
on. The recommended replacement is clangd.
- ...
AST Matchers
------------
- ...
clang-format
------------
- Option ``SpacesInLineCommentPrefix`` has been added to control the
number of spaces in a line comments prefix.
- Option ``SortIncludes`` has been updated from a ``bool`` to an
``enum`` with backwards compatibility. In addition to the previous
``true``/``false`` states (now ``CaseSensitive``/``Never``), a third
state has been added (``CaseInsensitive``) which causes an alphabetical sort
with case used as a tie-breaker.
.. code-block:: c++
// Never (previously false)
#include "B/A.h"
#include "A/B.h"
#include "a/b.h"
#include "A/b.h"
#include "B/a.h"
// CaseSensitive (previously true)
#include "A/B.h"
#include "A/b.h"
#include "B/A.h"
#include "B/a.h"
#include "a/b.h"
// CaseInsensitive
#include "A/B.h"
#include "A/b.h"
#include "a/b.h"
#include "B/A.h"
#include "B/a.h"
- ``BasedOnStyle: InheritParentConfig`` allows to use the ``.clang-format`` of
the parent directories to overwrite only parts of it.
- Option ``IndentAccessModifiers`` has been added to be able to give access
modifiers their own indentation level inside records.
- Option ``ShortNamespaceLines`` has been added to give better control
over ``FixNamespaceComments`` when determining a namespace length.
- Support for Whitesmiths has been improved, with fixes for ``namespace`` blocks
and ``case`` blocks and labels.
libclang
--------
- ...
Static Analyzer
---------------
- ...
.. _release-notes-ubsan:
Undefined Behavior Sanitizer (UBSan)
------------------------------------
Core Analysis Improvements
==========================
- ...
New Issues Found
================
- ...
Python Binding Changes
----------------------
The following methods have been added:
- ...
Significant Known Problems
==========================
Additional Information
======================
A wide variety of additional information is available on the `Clang web
page <https://clang.llvm.org/>`_. The web page contains versions of the
2020-03-23 05:18:40 +08:00
API documentation which are up-to-date with the Git version of
the source code. You can access versions of these documents specific to
this release by going into the "``clang/docs/``" directory in the Clang
tree.
If you have any questions or comments about Clang, please feel free to
contact us via the `mailing
list <https://lists.llvm.org/mailman/listinfo/cfe-dev>`_.