forked from OSchip/llvm-project
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ReStructuredText
596 lines
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ReStructuredText
===========================================
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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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Potentially Breaking Changes
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============================
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These changes are ones which we think may surprise users when upgrading to
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Clang |release| because of the opportunity they pose for disruption to existing
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code bases.
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- Clang will now correctly diagnose as ill-formed a constant expression where an
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enum without a fixed underlying type is set to a value outside the range of
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the enumeration's values.
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.. code-block:: c++
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enum E { Zero, One, Two, Three, Four };
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constexpr E Val1 = (E)3; // Ok
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constexpr E Val2 = (E)7; // Ok
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constexpr E Val3 = (E)8; // Now diagnosed as out of the range [0, 7]
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constexpr E Val4 = (E)-1; // Now diagnosed as out of the range [0, 7]
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Due to the extended period of time this bug was present in major C++
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implementations (including Clang), this error has the ability to be
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downgraded into a warning (via: ``-Wno-error=enum-constexpr-conversion``) to
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provide a transition period for users. This diagnostic is expected to turn
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into an error-only diagnostic in the next Clang release. Fixes
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`Issue 50055 <https://github.com/llvm/llvm-project/issues/50055>`_.
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- ``-Wincompatible-function-pointer-types`` now defaults to an error in all C
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language modes. It may be downgraded to a warning with
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``-Wno-error=incompatible-function-pointer-types`` or disabled entirely with
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``-Wno-implicit-function-pointer-types``.
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**NOTE:** We recommend that projects using configure scripts verify that the
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results do not change before/after setting
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``-Werror=incompatible-function-pointer-types`` to avoid incompatibility with
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Clang 16.
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.. code-block:: c
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void func(const int *i);
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void other(void) {
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void (*fp)(int *) = func; // Previously a warning, now a downgradable error.
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}
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- Clang now disallows types whose sizes aren't a multiple of their alignments
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to be used as the element type of arrays.
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.. code-block:: c
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typedef char int8_a16 __attribute__((aligned(16)));
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int8_a16 array[4]; // Now diagnosed as the element size not being a multiple of the array alignment.
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- When compiling for Windows in MSVC compatibility mode (for example by using
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clang-cl), the compiler will now propagate dllimport/export declspecs in
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explicit specializations of class template member functions (`Issue 54717
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<https://github.com/llvm/llvm-project/issues/54717>`_):
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.. code-block:: c++
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template <typename> struct __declspec(dllexport) S {
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void f();
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};
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template<> void S<int>::f() {} // clang-cl will now dllexport this.
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This matches what MSVC does, so it improves compatibility, but it can also
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cause errors for code which clang-cl would previously accept, for example:
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.. code-block:: c++
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template <typename> struct __declspec(dllexport) S {
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void f();
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};
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template<> void S<int>::f() = delete; // Error: cannot delete dllexport function.
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.. code-block:: c++
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template <typename> struct __declspec(dllimport) S {
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void f();
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};
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template<> void S<int>::f() {}; // Error: cannot define dllimport function.
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These errors also match MSVC's behavior.
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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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Bug Fixes
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---------
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- Correct ``_Static_assert`` to accept the same set of extended integer
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constant expressions as is accpted in other contexts that accept them.
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This fixes `Issue 57687 <https://github.com/llvm/llvm-project/issues/57687>`_.
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- Fixes an accepts-invalid bug in C when using a ``_Noreturn`` function
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specifier on something other than a function declaration. This fixes
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`Issue 56800 <https://github.com/llvm/llvm-project/issues/56800>`_.
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- Fix `#56772 <https://github.com/llvm/llvm-project/issues/56772>`_ - invalid
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destructor names were incorrectly accepted on template classes.
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- Improve compile-times with large dynamic array allocations with trivial
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constructors. This fixes
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`Issue 56774 <https://github.com/llvm/llvm-project/issues/56774>`_.
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- No longer assert/miscompile when trying to make a vectorized ``_BitInt`` type
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using the ``ext_vector_type`` attribute (the ``vector_size`` attribute was
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already properly diagnosing this case).
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- Fix clang not properly diagnosing the failing subexpression when chained
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binary operators are used in a ``static_assert`` expression.
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- Fix a crash when evaluating a multi-dimensional array's array filler
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expression is element-dependent. This fixes
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`Issue 50601 <https://github.com/llvm/llvm-project/issues/56016>`_.
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- Fixed a crash-on-valid with consteval evaluation of a list-initialized
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constructor for a temporary object. This fixes
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`Issue 55871 <https://github.com/llvm/llvm-project/issues/55871>`_.
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- Fix `#57008 <https://github.com/llvm/llvm-project/issues/57008>`_ - Builtin
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C++ language extension type traits instantiated by a template with unexpected
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number of arguments cause an assertion fault.
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- Fix multi-level pack expansion of undeclared function parameters.
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This fixes `Issue 56094 <https://github.com/llvm/llvm-project/issues/56094>`_.
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- Fix `#57151 <https://github.com/llvm/llvm-project/issues/57151>`_.
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``-Wcomma`` is emitted for void returning functions.
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- ``-Wtautological-compare`` missed warnings for tautological comparisons
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involving a negative integer literal. This fixes
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`Issue 42918 <https://github.com/llvm/llvm-project/issues/42918>`_.
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- Fix a crash when generating code coverage information for an
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``if consteval`` statement. This fixes
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`Issue 57377 <https://github.com/llvm/llvm-project/issues/57377>`_.
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- Fix assert that triggers a crash during template name lookup when a type was
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incomplete but was not also a TagType. This fixes
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`Issue 57387 <https://github.com/llvm/llvm-project/issues/57387>`_.
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- Fix a crash when emitting a concept-related diagnostic. This fixes
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`Issue 57415 <https://github.com/llvm/llvm-project/issues/57415>`_.
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- Fix a crash when attempting to default a virtual constexpr non-special member
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function in a derived class. This fixes
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`Issue 57431 <https://github.com/llvm/llvm-project/issues/57431>`_
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- Fix a crash where we attempt to define a deleted destructor. This fixes
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`Issue 57516 <https://github.com/llvm/llvm-project/issues/57516>`_
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- Fix ``__builtin_assume_aligned`` crash when the 1st arg is array type. This fixes
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`Issue 57169 <https://github.com/llvm/llvm-project/issues/57169>`_
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- Clang configuration files are now read through the virtual file system
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rather than the physical one, if these are different.
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- Clang will now no longer treat a C 'overloadable' function without a prototype as
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a variadic function with the attribute. This should make further diagnostics more
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clear.
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- Fixes to builtin template emulation of regular templates.
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`Issue 42102 <https://github.com/llvm/llvm-project/issues/42102>`_
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`Issue 51928 <https://github.com/llvm/llvm-project/issues/51928>`_
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- A SubstTemplateTypeParmType can now represent the pack index for a
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substitution from an expanded pack.
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`Issue 56099 <https://github.com/llvm/llvm-project/issues/56099>`_
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- Fix `-Wpre-c++17-compat` crashing Clang when compiling C++20 code which
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contains deduced template specializations. This Fixes
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`Issue 57369 <https://github.com/llvm/llvm-project/issues/57369>`_
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`Issue 57643 <https://github.com/llvm/llvm-project/issues/57643>`_
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`Issue 57793 <https://github.com/llvm/llvm-project/issues/57793>`_
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- Respect constructor constraints during class template argument deduction (CTAD).
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This is the suggested resolution to CWG DR2628.
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`Issue 57646 <https://github.com/llvm/llvm-project/issues/57646>`_
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`Issue 43829 <https://github.com/llvm/llvm-project/issues/43829>`_
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- Fixed a crash in C++20 mode in Clang and Clangd when compile source
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with compilation errors.
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`Issue 53628 <https://github.com/llvm/llvm-project/issues/53628>`_
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- The template arguments of a variable template being accessed as a
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member will now be represented in the AST.
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- Fix incorrect handling of inline builtins with asm labels.
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- Finished implementing C++ DR2565, which results in a requirement becoming
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not satisfied in the event of an instantiation failures in a requires expression's
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parameter list. We previously handled this correctly in a constraint evaluation
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context, but not in a requires clause evaluated as a boolean.
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Improvements to Clang's diagnostics
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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- Clang will now check compile-time determinable string literals as format strings.
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Fixes `Issue 55805: <https://github.com/llvm/llvm-project/issues/55805>`_.
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- ``-Wformat`` now recognizes ``%b`` for the ``printf``/``scanf`` family of
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functions and ``%B`` for the ``printf`` family of functions. Fixes
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`Issue 56885: <https://github.com/llvm/llvm-project/issues/56885>`_.
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- Introduced ``-Wsingle-bit-bitfield-constant-conversion``, grouped under
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``-Wbitfield-constant-conversion``, which diagnoses implicit truncation when
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``1`` is assigned to a 1-bit signed integer bitfield. This fixes
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`Issue 53253 <https://github.com/llvm/llvm-project/issues/53253>`_. To reduce
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potential false positives, this diagnostic will not diagnose use of the
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``true`` macro (from ``<stdbool.h>>`) in C language mode despite the macro
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being defined to expand to ``1``.
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- Clang will now print more information about failed static assertions. In
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particular, simple static assertion expressions are evaluated to their
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compile-time value and printed out if the assertion fails.
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- Diagnostics about uninitialized ``constexpr`` varaibles have been improved
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to mention the missing constant initializer.
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- Correctly diagnose a future keyword if it exist as a keyword in the higher
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language version and specifies in which version it will be a keyword. This
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supports both c and c++ language.
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- When diagnosing multi-level pack expansions of mismatched lengths, Clang will
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now, in most cases, be able to point to the relevant outer parameter.
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- ``no_sanitize("...")`` on a global variable for known but not relevant
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sanitizers is now just a warning. It now says that this will be ignored
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instead of incorrectly saying no_sanitize only applies to functions and
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methods.
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- No longer mention ``reinterpet_cast`` in the invalid constant expression
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diagnostic note when in C mode.
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- Clang will now give a more suitale diagnostic for declaration of block
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scope identifiers that have external/internal linkage that has an initializer.
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Fixes `Issue 57478: <https://github.com/llvm/llvm-project/issues/57478>`_.
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- New analysis pass will now help preserve sugar when combining deductions, in an
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order agnostic way. This will be in effect when deducing template arguments,
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when deducing function return type from multiple return statements, for the
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conditional operator, and for most binary operations. Type sugar is combined
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in a way that strips the sugar which is different between terms, and preserves
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those which are common.
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- Correctly diagnose use of an integer literal without a suffix whose
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underlying type is ``long long`` or ``unsigned long long`` as an extension in
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C89 mode . Clang previously only diagnosed if the literal had an explicit
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``LL`` suffix.
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- Clang now correctly diagnoses index that refers past the last possible element
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of FAM-like arrays.
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- Clang now correctly diagnoses a warning when defercencing a void pointer in C mode.
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This fixes `Issue 53631 <https://github.com/llvm/llvm-project/issues/53631>`_
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- Clang will now diagnose an overload set where a candidate has a constraint that
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refers to an expression with a previous error as nothing viable, so that it
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doesn't generate strange cascading errors, particularly in cases where a
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subsuming constraint fails, which would result in a less-specific overload to
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be selected.
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- Add a fix-it hint for the ``-Wdefaulted-function-deleted`` warning to
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explicitly delete the function.
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- Fixed an accidental duplicate diagnostic involving the declaration of a
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function definition without a prototype which is preceded by a static
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declaration of the function with a prototype. Fixes
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`Issue 58181 <https://github.com/llvm/llvm-project/issues/58181>`_.
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Non-comprehensive list of changes in this release
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-------------------------------------------------
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- It's now possible to set the crash diagnostics directory through
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the environment variable ``CLANG_CRASH_DIAGNOSTICS_DIR``.
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The ``-fcrash-diagnostics-dir`` flag takes precedence.
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- When using header modules, inclusion of a private header and violations of
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the `use-declaration rules
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<https://clang.llvm.org/docs/Modules.html#use-declaration>`_ are now
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diagnosed even when the includer is a textual header. This change can be
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temporarily reversed with ``-Xclang
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-fno-modules-validate-textual-header-includes``, but this flag will be
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removed in a future Clang release.
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- Unicode support has been updated to support Unicode 15.0.
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New unicode codepoints are supported as appropriate in diagnostics,
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C and C++ identifiers, and escape sequences.
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- Clang now supports loading multiple configuration files. The files from
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default configuration paths are loaded first, unless ``--no-default-config``
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option is used. All files explicitly specified using ``--config=`` option
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are loaded afterwards.
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- When loading default configuration files, clang now unconditionally uses
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the real target triple (respecting options such as ``--target=`` and ``-m32``)
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rather than the executable prefix. The respective configuration files are
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also loaded when clang is called via an executable without a prefix (e.g.
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plain ``clang``).
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- Default configuration paths were partially changed. Clang now attempts to load
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``<triple>-<driver>.cfg`` first, and falls back to loading both
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``<driver>.cfg`` and ``<triple>.cfg`` if the former is not found. `Triple`
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is the target triple and `driver` first tries the canonical name
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for the driver (respecting ``--driver-mode=``), and then the name found
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in the executable.
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New Compiler Flags
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------------------
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- Implemented `-fcoro-aligned-allocation` flag. This flag implements
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Option 2 of P2014R0 aligned allocation of coroutine frames
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(`P2014R0 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2014r0.pdf>`_).
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With this flag, the coroutines will try to lookup aligned allocation
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function all the time. The compiler will emit an error if it fails to
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find aligned allocation function. So if the user code implemented self
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defined allocation function for coroutines, the existing code will be
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broken. A little divergence with P2014R0 is that clang will lookup
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`::operator new(size_t, std::aligned_val_t, nothrow_t)` if there is
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`get_return_object_on_allocation_failure`. We feel this is more consistent
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with the intention.
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- Added ``--no-default-config`` to disable automatically loading configuration
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files using default paths.
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Deprecated Compiler Flags
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-------------------------
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- ``-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang``
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has been deprecated. The flag will be removed in Clang 18.
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``-ftrivial-auto-var-init=zero`` is now available unconditionally, to be
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compatible with GCC.
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Modified Compiler Flags
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-----------------------
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- Clang now permits specifying ``--config=`` multiple times, to load multiple
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configuration files.
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Removed Compiler Flags
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-------------------------
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New Pragmas in Clang
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--------------------
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- ...
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Attribute Changes in Clang
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--------------------------
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- Added support for ``__attribute__((guard(nocf)))`` and C++-style
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``[[clang::guard(nocf)]]``, which is equivalent to ``__declspec(guard(nocf))``
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when using the MSVC environment. This is to support enabling Windows Control
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Flow Guard checks with the ability to disable them for specific functions when
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using the MinGW environment. This attribute is only available for Windows
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targets.
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- Introduced a new function attribute ``__attribute__((nouwtable))`` to suppress
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LLVM IR ``uwtable`` function attribute.
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- Updated the value returned by ``__has_c_attribute(nodiscard)`` to ``202003L``
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based on the final date specified by the C2x committee draft. We already
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supported the ability to specify a message in the attribute, so there were no
|
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changes to the attribute behavior.
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- Updated the value returned by ``__has_c_attribute(fallthrough)`` to ``201910L``
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based on the final date specified by the C2x committee draft. We previously
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used ``201904L`` (the date the proposal was seen by the committee) by mistake.
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There were no other changes to the attribute behavior.
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Windows Support
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---------------
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- For the MinGW driver, added the options ``-mguard=none``, ``-mguard=cf`` and
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``-mguard=cf-nochecks`` (equivalent to ``/guard:cf-``, ``/guard:cf`` and
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``/guard:cf,nochecks`` in clang-cl) for enabling Control Flow Guard checks
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and generation of address-taken function table.
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AIX Support
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-----------
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* When using ``-shared``, the clang driver now invokes llvm-nm to create an
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export list if the user doesn't specify one via linker flag or pass an
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alternative export control option.
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C Language Changes in Clang
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---------------------------
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- Adjusted ``-Wformat`` warnings according to `WG14 N2562 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2562.pdf>`_.
|
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Clang will now consider default argument promotions in ``printf``, and remove
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unnecessary warnings. Especially ``int`` argument with specifier ``%hhd`` and
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``%hd``.
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C2x Feature Support
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-------------------
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- Implemented `WG14 N2662 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2662.pdf>`_,
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so the [[maybe_unused]] attribute may be applied to a label to silence an
|
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``-Wunused-label`` warning.
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- Implemented `WG14 N2508 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2508.pdf>`_,
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so labels can placed everywhere inside a compound statement.
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- Implemented `WG14 N2927 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm>`_,
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the Not-so-magic ``typeof`` operator. Also implemented
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`WG14 N2930 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2930.pdf>`_,
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renaming ``remove_quals``, so the ``typeof_unqual`` operator is also
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supported. Both of these operators are supported only in C2x mode. The
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``typeof`` operator specifies the type of the given parenthesized expression
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operand or type name, including all qualifiers. The ``typeof_unqual``
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operator is similar to ``typeof`` except that all qualifiers are removed,
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including atomic type qualification and type attributes which behave like a
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qualifier, such as an address space attribute.
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.. code-block:: c
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__attribute__((address_space(1))) const _Atomic int Val;
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typeof(Val) OtherVal; // type is '__attribute__((address_space(1))) const _Atomic int'
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typeof_unqual(Val) OtherValUnqual; // type is 'int'
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C++ Language Changes in Clang
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-----------------------------
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- Implemented DR692, DR1395 and DR1432. Use the ``-fclang-abi-compat=15`` option
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to get the old partial ordering behavior regarding packs. Note that the fix for
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DR1432 is speculative that there is no wording or even resolution for this issue.
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A speculative fix for DR1432 is needed because it fixes regressions caused by DR692.
|
||
- Clang's default C++/ObjC++ standard is now ``gnu++17`` instead of ``gnu++14``.
|
||
This means Clang will by default accept code using features from C++17 and
|
||
conforming GNU extensions. Projects incompatible with C++17 can add
|
||
``-std=gnu++14`` to their build settings to restore the previous behaviour.
|
||
|
||
C++20 Feature Support
|
||
^^^^^^^^^^^^^^^^^^^^^
|
||
- Support capturing structured bindings in lambdas
|
||
(`P1091R3 <https://wg21.link/p1091r3>`_ and `P1381R1 <https://wg21.link/P1381R1>`_).
|
||
This fixes issues `Issue 52720 <https://github.com/llvm/llvm-project/issues/52720>`_,
|
||
`Issue 54300 <https://github.com/llvm/llvm-project/issues/54300>`_,
|
||
`Issue 54301 <https://github.com/llvm/llvm-project/issues/54301>`_,
|
||
and `Issue 49430 <https://github.com/llvm/llvm-project/issues/49430>`_.
|
||
- Consider explicitly defaulted constexpr/consteval special member function
|
||
template instantiation to be constexpr/consteval even though a call to such
|
||
a function cannot appear in a constant expression.
|
||
(C++14 [dcl.constexpr]p6 (CWG DR647/CWG DR1358))
|
||
- Correctly defer dependent immediate function invocations until template instantiation.
|
||
This fixes `Issue 55601 <https://github.com/llvm/llvm-project/issues/55601>`_.
|
||
- Implemented "Conditionally Trivial Special Member Functions" (`P0848 <https://wg21.link/p0848r3>`_).
|
||
Note: The handling of deleted functions is not yet compliant, as Clang
|
||
does not implement `DR1496 <https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1496>`_
|
||
and `DR1734 <https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1734>`_.
|
||
- Class member variables are now in scope when parsing a ``requires`` clause. Fixes
|
||
`Issue 55216 <https://github.com/llvm/llvm-project/issues/55216>`_.
|
||
- Correctly set expression evaluation context as 'immediate function context' in
|
||
consteval functions.
|
||
This fixes `Issue 51182 <https://github.com/llvm/llvm-project/issues/51182>`_.
|
||
- Fixes an assert crash caused by looking up missing vtable information on ``consteval``
|
||
virtual functions. Fixes `Issue 55065 <https://github.com/llvm/llvm-project/issues/55065>`_.
|
||
- Skip rebuilding lambda expressions in arguments of immediate invocations.
|
||
This fixes `Issue 56183 <https://github.com/llvm/llvm-project/issues/56183>`_,
|
||
`Issue 51695 <https://github.com/llvm/llvm-project/issues/51695>`_,
|
||
`Issue 50455 <https://github.com/llvm/llvm-project/issues/50455>`_,
|
||
`Issue 54872 <https://github.com/llvm/llvm-project/issues/54872>`_,
|
||
`Issue 54587 <https://github.com/llvm/llvm-project/issues/54587>`_.
|
||
- Clang now correctly delays the instantiation of function constraints until
|
||
the time of checking, which should now allow the libstdc++ ranges implementation
|
||
to work for at least trivial examples. This fixes
|
||
`Issue 44178 <https://github.com/llvm/llvm-project/issues/44178>`_.
|
||
- Clang implements DR2621, correcting a defect in ``using enum`` handling. The
|
||
name is found via ordinary lookup so typedefs are found.
|
||
- Implemented `P0634r3 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0634r3.html>`_,
|
||
which removes the requirement for the ``typename`` keyword in certain contexts.
|
||
- Implemented The Equality Operator You Are Looking For (`P2468 <http://wg21.link/p2468r2>`_).
|
||
|
||
C++2b Feature Support
|
||
^^^^^^^^^^^^^^^^^^^^^
|
||
|
||
- Support label at end of compound statement (`P2324 <https://wg21.link/p2324r2>`_).
|
||
- Implemented `P1169R4: static operator() <https://wg21.link/P1169R4>`_.
|
||
|
||
CUDA/HIP Language Changes in Clang
|
||
----------------------------------
|
||
|
||
Objective-C Language Changes in Clang
|
||
-------------------------------------
|
||
|
||
OpenCL C Language Changes in Clang
|
||
----------------------------------
|
||
|
||
...
|
||
|
||
ABI Changes in Clang
|
||
--------------------
|
||
|
||
OpenMP Support in Clang
|
||
-----------------------
|
||
|
||
...
|
||
|
||
CUDA Support in Clang
|
||
---------------------
|
||
|
||
- Clang now supports CUDA SDK up to 11.8
|
||
- Added support for targeting sm_{87,89,90} GPUs.
|
||
|
||
RISC-V Support in Clang
|
||
-----------------------
|
||
- ``sifive-7-rv32`` and ``sifive-7-rv64`` are no longer supported for ``-mcpu``.
|
||
Use ``sifive-e76``, ``sifive-s76``, or ``sifive-u74`` instead.
|
||
|
||
X86 Support in Clang
|
||
--------------------
|
||
- Support ``-mindirect-branch-cs-prefix`` for call and jmp to indirect thunk.
|
||
- Fix 32-bit ``__fastcall`` and ``__vectorcall`` ABI mismatch with MSVC.
|
||
|
||
DWARF Support in Clang
|
||
----------------------
|
||
|
||
Arm and AArch64 Support in Clang
|
||
--------------------------------
|
||
|
||
- The target(..) function attributes for AArch64 now accept:
|
||
|
||
* ``"arch=<arch>"`` strings, that specify the architecture for a function as per the ``-march`` option.
|
||
* ``"cpu=<cpu>"`` strings, that specify the cpu for a function as per the ``-mcpu`` option.
|
||
* ``"tune=<cpu>"`` strings, that specify the tune cpu for a function as per ``-mtune``.
|
||
* ``"+<feature>"``, ``"+no<feature>"`` enables/disables the specific feature, for compatibility with GCC target attributes.
|
||
* ``"<feature>"``, ``"no-<feature>"`` enabled/disables the specific feature, for backward compatibility with previous releases.
|
||
- ``-march`` values for targeting armv2, armv2A, armv3 and armv3M have been removed.
|
||
Their presence gave the impression that Clang can correctly generate code for
|
||
them, which it cannot.
|
||
- Add driver and tuning support for Neoverse V2 via the flag ``-mcpu=neoverse-v2``.
|
||
Native detection is also supported via ``-mcpu=native``.
|
||
|
||
Floating Point Support in Clang
|
||
-------------------------------
|
||
|
||
Internal API Changes
|
||
--------------------
|
||
|
||
Build System Changes
|
||
--------------------
|
||
|
||
AST Matchers
|
||
------------
|
||
|
||
clang-format
|
||
------------
|
||
- Add `RemoveSemicolon` option for removing `;` after a non-empty function definition.
|
||
|
||
clang-extdef-mapping
|
||
--------------------
|
||
|
||
libclang
|
||
--------
|
||
- Introduced the new function ``clang_getUnqualifiedType``, which mimics
|
||
the behavior of ``QualType::getUnqualifiedType`` for ``CXType``.
|
||
- Introduced the new function ``clang_getNonReferenceType``, which mimics
|
||
the behavior of ``QualType::getNonReferenceType`` for ``CXType``.
|
||
- Introduced the new function ``clang_CXXMethod_isDeleted``, which queries
|
||
whether the method is declared ``= delete``.
|
||
- ``clang_Cursor_getNumTemplateArguments``, ``clang_Cursor_getTemplateArgumentKind``,
|
||
``clang_Cursor_getTemplateArgumentType``, ``clang_Cursor_getTemplateArgumentValue`` and
|
||
``clang_Cursor_getTemplateArgumentUnsignedValue`` now work on struct, class,
|
||
and partial template specialization cursors in addition to function cursors.
|
||
|
||
Static Analyzer
|
||
---------------
|
||
- Removed the deprecated ``-analyzer-store`` and
|
||
``-analyzer-opt-analyze-nested-blocks`` analyzer flags.
|
||
``scanbuild`` was also updated accordingly.
|
||
Passing these flags will result in a hard error.
|
||
|
||
.. _release-notes-sanitizers:
|
||
|
||
Sanitizers
|
||
----------
|
||
- ``-fsanitize-memory-param-retval`` is turned on by default. With
|
||
``-fsanitize=memory``, passing uninitialized variables to functions and
|
||
returning uninitialized variables from functions is more aggressively
|
||
reported. ``-fno-sanitize-memory-param-retval`` restores the previous
|
||
behavior.
|
||
|
||
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 on the Discourse forums (Clang Frontend category)
|
||
<https://discourse.llvm.org/c/clang/6>`_.
|