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===========================================
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Clang |release| |ReleaseNotesTitle|
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===========================================
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.. contents::
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:local:
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:depth: 2
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Written by the `LLVM Team <https://llvm.org/>`_
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.. only:: PreRelease
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.. warning::
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These are in-progress notes for the upcoming Clang |version| release.
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Release notes for previous releases can be found on
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`the Download Page <https://releases.llvm.org/download.html>`_.
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Introduction
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============
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This document contains the release notes for the Clang C/C++/Objective-C
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frontend, part of the LLVM Compiler Infrastructure, release |release|. Here we
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describe the status of Clang in some detail, including major
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improvements from the previous release and new feature work. For the
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general LLVM release notes, see `the LLVM
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documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM
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releases may be downloaded from the `LLVM releases web
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site <https://llvm.org/releases/>`_.
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For more information about Clang or LLVM, including information about the
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latest release, please see the `Clang Web Site <https://clang.llvm.org>`_ or the
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`LLVM Web Site <https://llvm.org>`_.
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Note that if you are reading this file from a Git checkout or the
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main Clang web page, this document applies to the *next* release, not
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the current one. To see the release notes for a specific release, please
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see the `releases page <https://llvm.org/releases/>`_.
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What's New in Clang |release|?
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==============================
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Some of the major new features and improvements to Clang are listed
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here. Generic improvements to Clang as a whole or to its underlying
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infrastructure are described first, followed by language-specific
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sections with improvements to Clang's support for those languages.
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Major New Features
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------------------
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- Clang now supports the ``-fzero-call-used-regs`` feature for x86. The purpose
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of this feature is to limit Return-Oriented Programming (ROP) exploits and
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information leakage. It works by zeroing out a selected class of registers
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before function return --- e.g., all GPRs that are used within the function.
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There is an analogous ``zero_call_used_regs`` attribute to allow for finer
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control of this feature.
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- Clang now supports randomizing structure layout in C. This feature is a
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compile-time hardening technique, making it more difficult for an attacker to
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retrieve data from structures. Specify randomization with the
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``randomize_layout`` attribute. The corresponding ``no_randomize_layout``
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attribute can be used to turn the feature off.
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A seed value is required to enable randomization, and is deterministic based
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on a seed value. Use the ``-frandomize-layout-seed=`` or
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``-frandomize-layout-seed-file=`` flags.
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.. note::
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Randomizing structure layout is a C-only feature.
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Bug Fixes
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---------
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- ``CXXNewExpr::getArraySize()`` previously returned a ``llvm::Optional``
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wrapping a ``nullptr`` when the ``CXXNewExpr`` did not have an array
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size expression. This was fixed and ``::getArraySize()`` will now always
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either return ``None`` or a ``llvm::Optional`` wrapping a valid ``Expr*``.
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This fixes `Issue 53742 <https://github.com/llvm/llvm-project/issues/53742>`_.
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- We now ignore full expressions when traversing cast subexpressions. This
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fixes `Issue 53044 <https://github.com/llvm/llvm-project/issues/53044>`_.
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- Allow ``-Wno-gnu`` to silence GNU extension diagnostics for pointer
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arithmetic diagnostics. Fixes `Issue 54444
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<https://github.com/llvm/llvm-project/issues/54444>`_.
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- Placeholder constraints, as in ``Concept auto x = f();``, were not checked
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when modifiers like ``auto&`` or ``auto**`` were added. These constraints are
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now checked.
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This fixes `Issue 53911 <https://github.com/llvm/llvm-project/issues/53911>`_
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and `Issue 54443 <https://github.com/llvm/llvm-project/issues/54443>`_.
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- Previously invalid member variables with template parameters would crash clang.
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Now fixed by setting identifiers for them.
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This fixes `Issue 28475 (PR28101) <https://github.com/llvm/llvm-project/issues/28475>`_.
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- Now allow the ``restrict`` and ``_Atomic`` qualifiers to be used in
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conjunction with ``__auto_type`` to match the behavior in GCC. This fixes
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`Issue 53652 <https://github.com/llvm/llvm-project/issues/53652>`_.
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- No longer crash when specifying a variably-modified parameter type in a
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function with the ``naked`` attribute. This fixes
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`Issue 50541 <https://github.com/llvm/llvm-project/issues/50541>`_.
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- Allow multiple ``#pragma weak`` directives to name the same undeclared (if an
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alias, target) identifier instead of only processing one such ``#pragma weak``
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per identifier.
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Fixes `Issue 28985 <https://github.com/llvm/llvm-project/issues/28985>`_.
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- Assignment expressions in C11 and later mode now properly strip the _Atomic
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qualifier when determining the type of the assignment expression. Fixes
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`Issue 48742 <https://github.com/llvm/llvm-project/issues/48742>`_.
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- Improved the diagnostic when accessing a member of an atomic structure or
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union object in C; was previously an unhelpful error, but now issues a
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``-Watomic-access`` warning which defaults to an error. Fixes
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`Issue 54563 <https://github.com/llvm/llvm-project/issues/54563>`_.
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- Unevaluated lambdas in dependant contexts no longer result in clang crashing.
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This fixes Issues `50376 <https://github.com/llvm/llvm-project/issues/50376>`_,
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`51414 <https://github.com/llvm/llvm-project/issues/51414>`_,
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`51416 <https://github.com/llvm/llvm-project/issues/51416>`_,
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and `51641 <https://github.com/llvm/llvm-project/issues/51641>`_.
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- The builtin function __builtin_dump_struct would crash clang when the target
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struct contains a bitfield. It now correctly handles bitfields.
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This fixes Issue `Issue 54462 <https://github.com/llvm/llvm-project/issues/54462>`_.
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- Statement expressions are now disabled in default arguments in general.
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This fixes Issue `Issue 53488 <https://github.com/llvm/llvm-project/issues/53488>`_.
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- According to `CWG 1394 <https://wg21.link/cwg1394>`_ and
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`C++20 [dcl.fct.def.general]p2 <https://timsong-cpp.github.io/cppwp/n4868/dcl.fct.def#general-2.sentence-3>`_,
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Clang should not diagnose incomplete types in function definitions if the function body is "= delete;".
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This fixes Issue `Issue 52802 <https://github.com/llvm/llvm-project/issues/52802>`_.
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- Unknown type attributes with a ``[[]]`` spelling are no longer diagnosed twice.
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This fixes Issue `Issue 54817 <https://github.com/llvm/llvm-project/issues/54817>`_.
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- Clang should no longer incorrectly diagnose a variable declaration inside of
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a lambda expression that shares the name of a variable in a containing
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if/while/for/switch init statement as a redeclaration.
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This fixes `Issue 54913 <https://github.com/llvm/llvm-project/issues/54913>`_.
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- Overload resolution for constrained function templates could use the partial
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order of constraints to select an overload, even if the parameter types of
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the functions were different. It now diagnoses this case correctly as an
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ambiguous call and an error. Fixes
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`Issue 53640 <https://github.com/llvm/llvm-project/issues/53640>`_.
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- No longer crash when trying to determine whether the controlling expression
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argument to a generic selection expression has side effects in the case where
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the expression is result dependent. This fixes
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`Issue 50227 <https://github.com/llvm/llvm-project/issues/50227>`_.
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- Fixed an assertion when constant evaluating an initializer for a GCC/Clang
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floating-point vector type when the width of the initialization is exactly
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the same as the elements of the vector being initialized.
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Fixes `Issue 50216 <https://github.com/llvm/llvm-project/issues/50216>`_.
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- Fixed a crash when the ``__bf16`` type is used such that its size or
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alignment is calculated on a target which does not support that type. This
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fixes `Issue 50171 <https://github.com/llvm/llvm-project/issues/50171>`_.
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- Fixed a false positive diagnostic about an unevaluated expression having no
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side effects when the expression is of VLA type and is an operand of the
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``sizeof`` operator. Fixes `Issue 48010 <https://github.com/llvm/llvm-project/issues/48010>`_.
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- Fixed a false positive diagnostic about scoped enumerations being a C++11
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extension in C mode. A scoped enumeration's enumerators cannot be named in C
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because there is no way to fully qualify the enumerator name, so this
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"extension" was unintentional and useless. This fixes
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`Issue 42372 <https://github.com/llvm/llvm-project/issues/42372>`_.
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- Clang will now find and emit a call to an allocation function in a
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promise_type body for coroutines if there is any allocation function
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declaration in the scope of promise_type. Additionally, to implement CWG2585,
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a coroutine will no longer generate a call to a global allocation function
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with the signature (std::size_t, p0, ..., pn).
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This fixes Issue `Issue 54881 <https://github.com/llvm/llvm-project/issues/54881>`_.
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Improvements to Clang's diagnostics
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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- ``-Wliteral-range`` will warn on floating-point equality comparisons with
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constants that are not representable in a casted value. For example,
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``(float) f == 0.1`` is always false.
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- ``-Winline-namespace-reopened-noninline`` now takes into account that the
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``inline`` keyword must appear on the original but not necessarily all
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extension definitions of an inline namespace and therefore points its note
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at the original definition. This fixes `Issue 50794 (PR51452)
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<https://github.com/llvm/llvm-project/issues/50794>`_.
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- ``-Wunused-but-set-variable`` now also warns if the variable is only used
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by unary operators.
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- ``-Wunused-variable`` no longer warn for references extending the lifetime
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of temporaries with side effects. This fixes `Issue 54489
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<https://github.com/llvm/llvm-project/issues/54489>`_.
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- Modified the behavior of ``-Wstrict-prototypes`` and added a new, related
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diagnostic ``-Wdeprecated-non-prototype``. The strict prototypes warning will
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now only diagnose deprecated declarations and definitions of functions
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without a prototype where the behavior in C2x will remain correct. This
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diagnostic remains off by default but is now enabled via ``-pedantic`` due to
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it being a deprecation warning. ``-Wstrict-prototypes`` has no effect in C2x
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or when ``-fno-knr-functions`` is enabled. ``-Wdeprecated-non-prototype``
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will diagnose cases where the deprecated declarations or definitions of a
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function without a prototype will change behavior in C2x. Additionally, it
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will diagnose calls which pass arguments to a function without a prototype.
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This warning is enabled only when the ``-Wdeprecated-non-prototype`` option
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is enabled at the function declaration site, which allows a developer to
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disable the diagnostic for all callers at the point of declaration. This
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diagnostic is grouped under the ``-Wstrict-prototypes`` warning group, but is
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enabled by default. ``-Wdeprecated-non-prototype`` has no effect in C2x or
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when ``-fno-knr-functions`` is enabled.
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- Clang now appropriately issues an error in C when a definition of a function
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without a prototype and with no arguments is an invalid redeclaration of a
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function with a prototype. e.g., ``void f(int); void f() {}`` is now properly
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diagnosed.
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- The ``-Wimplicit-function-declaration`` warning diagnostic now defaults to
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an error in C99 and later. Prior to C2x, it may be downgraded to a warning
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with ``-Wno-error=implicit-function-declaration``, or disabled entirely with
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``-Wno-implicit-function-declaration``. As of C2x, support for implicit
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function declarations has been removed, and the warning options will have no
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effect.
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- The ``-Wimplicit-int`` warning diagnostic now defaults to an error in C99 and
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later. Prior to C2x, it may be downgraded to a warning with
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``-Wno-error=implicit-int``, or disabled entirely with ``-Wno-implicit-int``.
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As of C2x, support for implicit int has been removed, and the warning options
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will have no effect. Specifying ``-Wimplicit-int`` in C89 mode will now issue
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warnings instead of being a noop.
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- No longer issue a "declaration specifiers missing, defaulting to int"
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diagnostic in C89 mode because it is not an extension in C89, it was valid
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code. The diagnostic has been removed entirely as it did not have a
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diagnostic group to disable it, but it can be covered wholly by
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``-Wimplicit-int``.
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- ``-Wmisexpect`` warns when the branch weights collected during profiling
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conflict with those added by ``llvm.expect``.
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- ``-Wthread-safety-analysis`` now considers overloaded compound assignment and
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increment/decrement operators as writing to their first argument, thus
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requiring an exclusive lock if the argument is guarded.
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- ``-Wenum-conversion`` now warns on converting a signed enum of one type to an
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unsigned enum of a different type (or vice versa) rather than
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``-Wsign-conversion``.
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- Added the ``-Wunreachable-code-generic-assoc`` diagnostic flag (grouped under
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the ``-Wunreachable-code`` flag) which is enabled by default and warns the
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user about ``_Generic`` selection associations which are unreachable because
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the type specified is an array type or a qualified type.
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- Added the ``-Wgnu-line-marker`` diagnostic flag (grouped under the ``-Wgnu``
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flag) which is a portability warning about use of GNU linemarker preprocessor
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directives. Fixes `Issue 55067 <https://github.com/llvm/llvm-project/issues/55067>`_.
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- Using ``#elifdef`` and ``#elifndef`` that are incompatible with C/C++
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standards before C2x/C++2b are now warned via ``-pedantic``. Additionally,
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on such language mode, ``-Wpre-c2x-compat`` and ``-Wpre-c++2b-compat``
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diagnostic flags report a compatibility issue.
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Fixes `Issue 55306 <https://github.com/llvm/llvm-project/issues/55306>`_.
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- Clang now checks for stack resource exhaustion when recursively parsing
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declarators in order to give a diagnostic before we run out of stack space.
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This fixes `Issue 51642 <https://github.com/llvm/llvm-project/issues/51642>`_.
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- Unknown preprocessor directives in a skipped conditional block are now given
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a typo correction suggestion if the given directive is sufficiently similar
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to another preprocessor conditional directive. For example, if ``#esle``
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appears in a skipped block, we will warn about the unknown directive and
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suggest ``#else`` as an alternative. ``#elifdef`` and ``#elifndef`` are only
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suggested when in C2x or C++2b mode. Fixes
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`Issue 51598 <https://github.com/llvm/llvm-project/issues/51598>`_.
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Non-comprehensive list of changes in this release
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-------------------------------------------------
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- Improve __builtin_dump_struct:
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- Support bitfields in struct and union.
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- Improve the dump format, dump both bitwidth(if its a bitfield) and field
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value.
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- Remove anonymous tag locations and flatten anonymous struct members.
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- Beautify dump format, add indent for struct members.
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- Support passing additional arguments to the formatting function, allowing
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use with ``fprintf`` and similar formatting functions.
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- Support use within constant evaluation in C++, if a ``constexpr``
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formatting function is provided.
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- Support formatting of base classes in C++.
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- Support calling a formatting function template in C++, which can provide
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custom formatting for non-aggregate types.
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- Previously disabled sanitizer options now enabled by default:
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- ASAN_OPTIONS=detect_stack_use_after_return=1 (only on Linux).
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- MSAN_OPTIONS=poison_in_dtor=1.
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New Compiler Flags
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------------------
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- Added the ``-fno-knr-functions`` flag to allow users to opt into the C2x
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behavior where a function with an empty parameter list is treated as though
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the parameter list were ``void``. There is no ``-fknr-functions`` or
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``-fno-no-knr-functions`` flag; this feature cannot be disabled in language
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modes where it is required, such as C++ or C2x.
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- A new ARM pass to workaround Cortex-A57 Erratum 1742098 and Cortex-A72 Erratum
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1655431 can be enabled using ``-mfix-cortex-a57-aes-1742098`` or
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``-mfix-cortex-a72-aes-1655431``. The pass is enabled when using either of
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these cpus with ``-mcpu=`` and can be disabled using
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``-mno-fix-cortex-a57-aes-1742098`` or ``-mno-fix-cortex-a72-aes-1655431``.
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Deprecated Compiler Flags
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-------------------------
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Modified Compiler Flags
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-----------------------
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Removed Compiler Flags
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-------------------------
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- Removed the ``-fno-concept-satisfaction-caching`` flag. The flag was added
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at the time when the draft of C++20 standard did not permit caching of
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atomic constraints. The final standard permits such caching, see
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`WG21 P2104R0 <http://wg21.link/p2104r0>`_.
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New Pragmas in Clang
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--------------------
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- Added support for MSVC's ``#pragma function``, which tells the compiler to
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generate calls to functions listed in the pragma instead of using the
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builtins.
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- Added support for MSVC's ``#pragma alloc_text``. The pragma names the code
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section functions are placed in. The pragma only applies to functions with
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C linkage.
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- ...
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Attribute Changes in Clang
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--------------------------
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- Added support for parameter pack expansion in ``clang::annotate``.
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- The ``overloadable`` attribute can now be written in all of the syntactic
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locations a declaration attribute may appear.
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This fixes `Issue 53805 <https://github.com/llvm/llvm-project/issues/53805>`_.
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- Improved namespace attributes handling:
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- Handle GNU attributes before a namespace identifier and subsequent
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attributes of different kinds.
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- Emit error on GNU attributes for a nested namespace definition.
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- Statement attributes ``[[clang::noinline]]`` and ``[[clang::always_inline]]``
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can be used to control inlining decisions at callsites.
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- ``#pragma clang attribute push`` now supports multiple attributes within a single directive.
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- The ``__declspec(naked)`` attribute can no longer be written on a member
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function in Microsoft compatibility mode, matching the behavior of cl.exe.
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- Attribute ``no_builtin`` should now affect the generated code. It now disables
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builtins (corresponding to the specific names listed in the attribute) in the
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body of the function the attribute is on.
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Windows Support
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---------------
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- Add support for MSVC-compatible ``/JMC``/``/JMC-`` flag in clang-cl (supports
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X86/X64/ARM/ARM64). ``/JMC`` could only be used when ``/Zi`` or ``/Z7`` is
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turned on. With this addition, clang-cl can be used in Visual Studio for the
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JustMyCode feature. Note, you may need to manually add ``/JMC`` as additional
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compile options in the Visual Studio since it currently assumes clang-cl does not support ``/JMC``.
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AIX Support
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-----------
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- The driver no longer adds ``-mignore-xcoff-visibility`` by default for AIX
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targets when no other visibility command-line options are in effect, as
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ignoring hidden visibility can silently have undesirable side effects (e.g
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when libraries depend on visibility to hide non-ABI facing entities). The
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``-mignore-xcoff-visibility`` option can be manually specified on the
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command-line to recover the previous behavior if desired.
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C Language Changes in Clang
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---------------------------
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- Finished implementing support for DR423. We already correctly handled
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stripping qualifiers from cast expressions, but we did not strip qualifiers
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on function return types. We now properly treat the function as though it
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were declarated with an unqualified, non-atomic return type. Fixes
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`Issue 39595 <https://github.com/llvm/llvm-project/issues/39595>`_.
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C2x Feature Support
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-------------------
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- Implemented `WG14 N2674 The noreturn attribute <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2764.pdf>`_.
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- Implemented `WG14 N2935 Make false and true first-class language features <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2935.pdf>`_.
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- Implemented `WG14 N2763 Adding a fundamental type for N-bit integers <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2763.pdf>`_.
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- Implemented `WG14 N2775 Literal suffixes for bit-precise integers <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2775.pdf>`_.
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- Implemented the ``*_WIDTH`` macros to complete support for
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`WG14 N2412 Two's complement sign representation for C2x <https://www9.open-std.org/jtc1/sc22/wg14/www/docs/n2412.pdf>`_.
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- Implemented `WG14 N2418 Adding the u8 character prefix <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2418.pdf>`_.
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- Removed support for implicit function declarations. This was a C89 feature
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that was removed in C99, but cannot be supported in C2x because it requires
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support for functions without prototypes, which no longer exist in C2x.
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- Implemented `WG14 N2841 No function declarators without prototypes <https://www9.open-std.org/jtc1/sc22/wg14/www/docs/n2841.htm>`_
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and `WG14 N2432 Remove support for function definitions with identifier lists <https://www9.open-std.org/jtc1/sc22/wg14/www/docs/n2432.pdf>`_.
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C++ Language Changes in Clang
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-----------------------------
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- Improved ``-O0`` code generation for calls to ``std::move``, ``std::forward``,
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``std::move_if_noexcept``, ``std::addressof``, and ``std::as_const``. These
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are now treated as compiler builtins and implemented directly, rather than
|
|
instantiating the definition from the standard library.
|
|
- Fixed mangling of nested dependent names such as ``T::a::b``, where ``T`` is a
|
|
template parameter, to conform to the Itanium C++ ABI and be compatible with
|
|
GCC. This breaks binary compatibility with code compiled with earlier versions
|
|
of clang; use the ``-fclang-abi-compat=14`` option to get the old mangling.
|
|
- Preprocessor character literals with a ``u8`` prefix are now correctly treated as
|
|
unsigned character literals. This fixes `Issue 54886 <https://github.com/llvm/llvm-project/issues/54886>`_.
|
|
- Stopped allowing constraints on non-template functions to be compliant with
|
|
dcl.decl.general p4.
|
|
|
|
C++20 Feature Support
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
- Diagnose consteval and constexpr issues that happen at namespace scope. This
|
|
partially addresses `Issue 51593 <https://github.com/llvm/llvm-project/issues/51593>`_.
|
|
- No longer attempt to evaluate a consteval UDL function call at runtime when
|
|
it is called through a template instantiation. This fixes
|
|
`Issue 54578 <https://github.com/llvm/llvm-project/issues/54578>`_.
|
|
|
|
- Implemented ``__builtin_source_location()``, which enables library support
|
|
for ``std::source_location``.
|
|
|
|
- The mangling scheme for C++20 modules has incompatibly changed. The
|
|
initial mangling was discovered not to be reversible, and the weak
|
|
ownership design decision did not give the backwards compatibility
|
|
that was hoped for. C++20 since added ``extern "C++"`` semantics
|
|
that can be used for such compatibility. The demangler now demangles
|
|
symbols with named module attachment.
|
|
|
|
C++2b Feature Support
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
- Implemented `P2128R6: Multidimensional subscript operator <https://wg21.link/P2128R6>`_.
|
|
- Implemented `P0849R8: auto(x): decay-copy in the language <https://wg21.link/P0849R8>`_.
|
|
- Implemented `P2242R3: Non-literal variables (and labels and gotos) in constexpr functions <https://wg21.link/P2242R3>`_.
|
|
|
|
CUDA/HIP Language Changes in Clang
|
|
----------------------------------
|
|
|
|
- Added `__noinline__` as a keyword to avoid diagnostics due to usage of
|
|
`__attribute__((__noinline__))` in CUDA/HIP programs.
|
|
|
|
Objective-C Language Changes in Clang
|
|
-------------------------------------
|
|
|
|
OpenCL C Language Changes in Clang
|
|
----------------------------------
|
|
|
|
...
|
|
|
|
ABI Changes in Clang
|
|
--------------------
|
|
|
|
- GCC doesn't pack non-POD members in packed structs unless the packed
|
|
attribute is also specified on the member. Clang historically did perform
|
|
such packing. Clang now matches the gcc behavior (except on Darwin and PS4).
|
|
You can switch back to the old ABI behavior with the flag:
|
|
``-fclang-abi-compat=14.0``.
|
|
|
|
OpenMP Support in Clang
|
|
-----------------------
|
|
|
|
...
|
|
|
|
CUDA Support in Clang
|
|
---------------------
|
|
|
|
- ...
|
|
|
|
X86 Support in Clang
|
|
--------------------
|
|
|
|
DWARF Support in Clang
|
|
----------------------
|
|
|
|
Arm and AArch64 Support in Clang
|
|
--------------------------------
|
|
|
|
Floating Point Support in Clang
|
|
-------------------------------
|
|
|
|
Internal API Changes
|
|
--------------------
|
|
|
|
- Added a new attribute flag ``AcceptsExprPack`` that when set allows
|
|
expression pack expansions in the parsed arguments of the corresponding
|
|
attribute. Additionally it introduces delaying of attribute arguments, adding
|
|
common handling for creating attributes that cannot be fully initialized
|
|
prior to template instantiation.
|
|
|
|
Build System Changes
|
|
--------------------
|
|
|
|
* CMake ``-DCLANG_DEFAULT_PIE_ON_LINUX=ON`` is now the default. This is used by
|
|
linux-gnu systems to decide whether ``-fPIE -pie`` is the default (instead of
|
|
``-fno-pic -no-pie``). This matches GCC installations on many Linux distros.
|
|
Note: linux-android and linux-musl always default to ``-fPIE -pie``, ignoring
|
|
this variable. ``-DCLANG_DEFAULT_PIE_ON_LINUX`` may be removed in the future.
|
|
|
|
AST Matchers
|
|
------------
|
|
|
|
- Expanded ``isInline`` narrowing matcher to support C++17 inline variables.
|
|
|
|
- Added ``forEachTemplateArgument`` matcher which creates a match every
|
|
time a ``templateArgument`` matches the matcher supplied to it.
|
|
|
|
clang-format
|
|
------------
|
|
|
|
- **Important change**: Renamed ``IndentRequires`` to ``IndentRequiresClause``
|
|
and changed the default for all styles from ``false`` to ``true``.
|
|
|
|
- Reworked and improved handling of concepts and requires. Added the
|
|
``RequiresClausePosition`` option as part of that.
|
|
|
|
- Changed ``BreakBeforeConceptDeclarations`` from ``Boolean`` to an enum.
|
|
|
|
- Option ``InsertBraces`` has been added to insert optional braces after control
|
|
statements.
|
|
|
|
libclang
|
|
--------
|
|
|
|
- ...
|
|
|
|
Static Analyzer
|
|
---------------
|
|
- `New CTU implementation
|
|
<https://discourse.llvm.org/t/rfc-much-faster-cross-translation-unit-ctu-analysis-implementation/61728>`_
|
|
that keeps the slow-down around 2x compared to the single-TU analysis, even
|
|
in case of complex C++ projects. Still, it finds the majority of the "old"
|
|
CTU findings. Besides, not more than ~3% of the bug reports are lost compared
|
|
to single-TU analysis, the lost reports are highly likely to be false
|
|
positives.
|
|
|
|
- Added a new checker ``alpha.unix.cstring.UninitializedRead`` this will check for uninitialized reads
|
|
from common memory copy/manipulation functions such as ``memcpy``, ``mempcpy``, ``memmove``, ``memcmp``, `
|
|
`strcmp``, ``strncmp``, ``strcpy``, ``strlen``, ``strsep`` and many more. Although
|
|
this checker currently is in list of alpha checkers due to a false positive.
|
|
|
|
.. _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
|
|
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>`_.
|