[llvm-branch-commits] [clang] be701ab - [Clang][Doc] Edit the Clang release notes
Tom Stellard via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Mon Feb 13 15:11:59 PST 2023
Author: Roy Jacobson
Date: 2023-02-13T15:10:51-08:00
New Revision: be701ab08f12daf9437c2db6d08a1731cf1df34c
URL: https://github.com/llvm/llvm-project/commit/be701ab08f12daf9437c2db6d08a1731cf1df34c
DIFF: https://github.com/llvm/llvm-project/commit/be701ab08f12daf9437c2db6d08a1731cf1df34c.diff
LOG: [Clang][Doc] Edit the Clang release notes
Do a large edit of the Clang release notes.
This is meant to be merged into the Clang 16.x branch.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D142578
Added:
Modified:
clang/docs/ReleaseNotes.rst
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index dffe19a34d18f..b32a84d1f6d3b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -13,7 +13,7 @@ Written by the `LLVM Team <https://llvm.org/>`_
.. warning::
These are in-progress notes for the upcoming Clang |version| release.
Release notes for previous releases can be found on
- `the Download Page <https://releases.llvm.org/download.html>`_.
+ `the Releases Page <https://llvm.org/releases>`_.
Introduction
============
@@ -23,43 +23,32 @@ frontend, part of the LLVM Compiler Infrastructure, release |release|. Here we
describe the status of Clang in some detail, including major
improvements from the previous release and new feature work. For the
general LLVM release notes, see `the LLVM
-documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM
-releases may be downloaded from the `LLVM releases web
-site <https://llvm.org/releases/>`_.
+documentation <https://llvm.org/docs/ReleaseNotes.html>`_. For the libc++ release notes,
+see `this page <https://libcxx.llvm.org/ReleaseNotes.html>`_. All LLVM releases
+may be downloaded from the `LLVM releases web site <https://llvm.org/releases/>`_.
For more information about Clang or LLVM, including information about the
latest release, please see the `Clang Web Site <https://clang.llvm.org>`_ or the
`LLVM Web Site <https://llvm.org>`_.
-Note that if you are reading this file from a Git checkout or the
-main Clang web page, this document applies to the *next* release, not
-the current one. To see the release notes for a specific release, please
-see the `releases page <https://llvm.org/releases/>`_.
-
Potentially Breaking Changes
============================
These changes are ones which we think may surprise users when upgrading to
Clang |release| because of the opportunity they pose for disruption to existing
code bases.
-- Clang will now correctly diagnose as ill-formed a constant expression where an
- enum without a fixed underlying type is set to a value outside the range of
- the enumeration's values.
-
- .. code-block:: c++
+- 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.
- enum E { Zero, One, Two, Three, Four };
- constexpr E Val1 = (E)3; // Ok
- constexpr E Val2 = (E)7; // Ok
- constexpr E Val3 = (E)8; // Now diagnosed as out of the range [0, 7]
- constexpr E Val4 = (E)-1; // Now diagnosed as out of the range [0, 7]
+- The ``-fexperimental-new-pass-manager`` and ``-fno-legacy-pass-manager``
+ flags have been removed. These flags have been silently ignored since Clang 15.
- Due to the extended period of time this bug was present in major C++
- implementations (including Clang), this error has the ability to be
- downgraded into a warning (via: ``-Wno-error=enum-constexpr-conversion``) to
- provide a transition period for users. This diagnostic is expected to turn
- into an error-only diagnostic in the next Clang release. Fixes
- `Issue 50055 <https://github.com/llvm/llvm-project/issues/50055>`_.
+- Clang's resource directory path previously included the full clang version.
+ It now includes only the major version. The new resource directory is
+ ``$prefix/lib/clang/$CLANG_MAJOR_VERSION`` and can be queried using
+ ``clang -print-resource-dir``, just like before.
- The ``-Wimplicit-function-declaration`` and ``-Wimplicit-int`` warnings
now default to an error in C99, C11, and C17. As of C2x,
@@ -89,17 +78,26 @@ code bases.
void (*fp)(int *) = func; // Previously a warning, now a downgradable error.
}
+- To match GCC, ``__ppc64__`` is no longer defined on PowerPC64 targets. Use
+ ``__powerpc64__`` instead.
+
+- ``-p`` is rejected for all targets which are not AIX or OpenBSD. ``-p`` led
+ to an ``-Wunused-command-line-argument`` warning in previous releases.
+
+C/C++ Language Potentially Breaking Changes
+-------------------------------------------
+
- Clang now disallows types whose sizes aren't a multiple of their alignments
to be used as the element type of arrays.
.. code-block:: c
- typedef char int8_a16 __attribute__((aligned(16)));
- int8_a16 array[4]; // Now diagnosed as the element size not being a multiple of the array alignment.
+ typedef char int8_a16 __attribute__((aligned(16)));
+ int8_a16 array[4]; // Now diagnosed as the element size not being a multiple of the array alignment.
- When compiling for Windows in MSVC compatibility mode (for example by using
clang-cl), the compiler will now propagate dllimport/export declspecs in
- explicit specializations of class template member functions (`Issue 54717
+ explicit specializations of class template member functions (`#54717
<https://github.com/llvm/llvm-project/issues/54717>`_):
.. code-block:: c++
@@ -143,8 +141,8 @@ code bases.
- Clang now diagnoses use of a bit-field as an instruction operand in Microsoft
style inline asm blocks as an error. Previously, a bit-field operand yielded
the address of the allocation unit the bit-field was stored within; reads or
- writes therefore had the potential to read or write nearby bit-fields. This
- change fixes `issue 57791 <https://github.com/llvm/llvm-project/issues/57791>`_.
+ writes therefore had the potential to read or write nearby bit-fields.
+ (`#57791 <https://github.com/llvm/llvm-project/issues/57791>`_)
.. code-block:: c++
@@ -158,8 +156,35 @@ code bases.
}
}
-- The ``-fexperimental-new-pass-manager`` and ``-fno-legacy-pass-manager``
- flags have been removed. These have been no-ops since 15.0.0.
+- Clang now diagnoses if structs/unions with the same name are
diff erent in
+
diff erent used modules. Behavior in C and Objective-C language modes now is
+ the same as in C++.
+
+C++ Specific Potentially Breaking Changes
+-----------------------------------------
+- Clang now prohibits non-inline externally-visible definitions in C++
+ standard header units as per ``[module.import/6]``. In Clang 15,
+ these definitions were allowed. Note that such definitions are ODR
+ violations if the header is included more than once.
+
+- Clang will now correctly diagnose as ill-formed a constant expression where an
+ enum without a fixed underlying type is set to a value outside the range of
+ the enumeration's values.
+
+ .. code-block:: c++
+
+ enum E { Zero, One, Two, Three, Four };
+ constexpr E Val1 = (E)3; // Ok
+ constexpr E Val2 = (E)7; // Ok
+ constexpr E Val3 = (E)8; // Now diagnosed as out of the range [0, 7]
+ constexpr E Val4 = (E)-1; // Now diagnosed as out of the range [0, 7]
+
+ Due to the extended period of time this bug was present in major C++
+ implementations (including Clang), this error has the ability to be
+ downgraded into a warning (via: ``-Wno-error=enum-constexpr-conversion``) to
+ provide a transition period for users. This diagnostic is expected to turn
+ into an error-only diagnostic in the next Clang release.
+ (`#50055 <https://github.com/llvm/llvm-project/issues/50055>`_)
- As a side effect of implementing DR692/DR1395/DR1432, Clang now rejects some
overloaded function templates as ambiguous when one of the candidates has a
@@ -176,25 +201,18 @@ code bases.
g(42);
}
-- Clang's resource dir used to include the full clang version. It will now
- include only the major version. The new resource directory is
- ``$prefix/lib/clang/$CLANG_MAJOR_VERSION`` and can be queried using
- ``clang -print-resource-dir``, just like before.
-
-- To match GCC, ``__ppc64__`` is no longer defined on PowerPC64 targets. Use
- ``__powerpc64__`` instead.
-
-- ``-p`` is rejected for all targets which are not AIX or OpenBSD. ``-p`` led
- to an ``-Wunused-command-line-argument`` warning in previous releases.
-
-- Clang now diagnoses non-inline externally-visible definitions in C++
- standard header units as per ``[module.import/6]``. Previously, in Clang-15,
- these definitions were allowed. Note that such definitions are ODR
- violations if the header is included more than once.
-
-- Clang now diagnoses if structs/unions with the same name are
diff erent in
-
diff erent used modules. Behavior in C and Objective-C language modes now is
- the same as in C++.
+ABI Changes in This Version
+---------------------------
+- 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, PS4 and AIX).
+ You can switch back to the old ABI behavior with the flag:
+ ``-fclang-abi-compat=15.0``.
+- GCC allows POD types to have defaulted special members. Clang historically
+ classified such types as non-POD (for the purposes of Itanium ABI). Clang now
+ matches the gcc behavior (except on Darwin, PS4, AIX and z/OS). You can switch
+ back to the old ABI behavior with the flag: ``-fclang-abi-compat=15.0``.
What's New in Clang |release|?
==============================
@@ -203,324 +221,234 @@ here. Generic improvements to Clang as a whole or to its underlying
infrastructure are described first, followed by language-specific
sections with improvements to Clang's support for those languages.
-Major New Features
+C++ Language Changes
+--------------------
+
+C++20 Feature Support
+^^^^^^^^^^^^^^^^^^^^^
+
+Newly implemented papers:
+
+- Implemented `P0848: Conditionally Trivial Special Member Functions <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>`_.
+
+- Implemented `P1091R3 <https://wg21.link/p1091r3>`_ and `P1381R1 <https://wg21.link/P1381R1>`_ to
+ support capturing structured bindings in lambdas (`#52720 <https://github.com/llvm/llvm-project/issues/52720>`_,
+ `#54300 <https://github.com/llvm/llvm-project/issues/54300>`_,
+ `#54301 <https://github.com/llvm/llvm-project/issues/54301>`_,
+ `#49430 <https://github.com/llvm/llvm-project/issues/49430>`_).
+
+- Implemented `P2468R2: The Equality Operator You Are Looking For <http://wg21.link/p2468r2>`_.
+
+- Implemented `P2113R0: Proposed resolution for 2019 comment CA 112 <https://wg21.link/P2113R0>`_
+ ([temp.func.order]p6.2.1 is not implemented, matching GCC).
+
+- Implemented `P0634R3: Down with typename! <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 `P0857R0: Fixing small-ish functionality gaps in constraints <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0857r0.html>`_,
+ which specifies constrained lambdas and constrained template *template-parameter*\s.
+
+- Implemented `P0960R3 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0960r3.html>`_
+ and `P1975R0 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1975r0.html>`_,
+ which allow parenthesized aggregate-initialization.
+
+Notable Bug Fixes to C++20 Features:
+
+- 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.
+ (`#44178 <https://github.com/llvm/llvm-project/issues/44178>`_)
+
+- 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.
+ (`#55601 <https://github.com/llvm/llvm-project/issues/55601>`_)
+
+- Correctly set expression evaluation context as 'immediate function context' in
+ consteval functions.
+ (`#51182 <https://github.com/llvm/llvm-project/issues/51182>`_)
+
+- Skip rebuilding lambda expressions in arguments of immediate invocations.
+ (`#56183 <https://github.com/llvm/llvm-project/issues/56183>`_,
+ `#51695 <https://github.com/llvm/llvm-project/issues/51695>`_,
+ `#50455 <https://github.com/llvm/llvm-project/issues/50455>`_,
+ `#54872 <https://github.com/llvm/llvm-project/issues/54872>`_,
+ `#54587 <https://github.com/llvm/llvm-project/issues/54587>`_)
+
+- Clang implements DR2621, correcting a defect in ``using enum`` handling. The
+ name is found via ordinary lookup so typedefs are found.
+
+- Implemented CWG2635 as a Defect Report, which prohibits structured bindings from being constrained.
+
+- When using header modules, inclusion of a private header and violations of
+ the `use-declaration rules
+ <https://clang.llvm.org/docs/Modules.html#use-declaration>`_ are now
+ diagnosed even when the includer is a textual header. This change can be
+ temporarily reversed with ``-Xclang
+ -fno-modules-validate-textual-header-includes``, but this flag will be
+ removed in a future Clang release.
+
+C++2b Feature Support
+^^^^^^^^^^^^^^^^^^^^^
+- Implemented `P2324R2: Support label at end of compound statement <https://wg21.link/p2324r2>`_.
+- Implemented `P1169R4: static operator() <https://wg21.link/P1169R4>`_ and `P2589R1: static operator[] <https://wg21.link/P2589R1>`_.
+- Implemented `P2513R3: char8_t Compatibility and Portability Fix <https://wg21.link/P2513R3>`_.
+ This change was applied to C++20 as a Defect Report.
+- Implemented `P2647R1: Permitting static constexpr variables in constexpr functions <https://wg21.link/P2647R1>`_.
+- Implemented `CWG2640: Allow more characters in an n-char sequence <https://wg21.link/CWG2640>`_.
+
+Resolutions to C++ Defect Reports
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Implemented `DR692 <https://wg21.link/cwg692>`_, `DR1395 <https://wg21.link/cwg1395>`_,
+ and `DR1432 <https://wg21.link/cwg1432>`_. The fix for DR1432 is speculative since the
+ issue is still open and has no proposed resolution at this time. A speculative fix
+ for DR1432 is needed to prevent regressions that would otherwise occur due to DR692.
+- Implemented `DR2358 <https://wg21.link/cwg2358>`_, which allows init captures in lambdas in default arguments.
+- Implemented `DR2654 <https://wg21.link/cwg2654>`_ which undeprecates
+ all compound assignments operations on volatile qualified variables.
+- Implemented `DR2631 <https://wg21.link/cwg2631>`_. Invalid ``consteval`` calls in default arguments and default
+ member initializers are diagnosed when and if the default is used.
+ This changes the value of ``std::source_location::current()``
+ used in default parameters calls compared to previous versions of Clang.
+ (`#56379 <https://github.com/llvm/llvm-project/issues/56379>`_)
+
+C Language Changes
------------------
+- Adjusted ``-Wformat`` warnings according to `WG14 N2562 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2562.pdf>`_.
+ Clang will now consider default argument promotions in ``printf``, and remove
+ unnecessary warnings. Especially ``int`` argument with specifier ``%hhd`` and
+ ``%hd``.
-Bug Fixes
----------
-- ``stdatomic.h`` will use the internal declarations when targeting pre-C++-23
- on Windows platforms as the MSVC support requires newer C++ standard.
-- Correct ``_Static_assert`` to accept the same set of extended integer
- constant expressions as is accpted in other contexts that accept them.
- This fixes `Issue 57687 <https://github.com/llvm/llvm-project/issues/57687>`_.
-- Fixes an accepts-invalid bug in C when using a ``_Noreturn`` function
- specifier on something other than a function declaration. This fixes
- `Issue 56800 <https://github.com/llvm/llvm-project/issues/56800>`_.
-- Fix `#56772 <https://github.com/llvm/llvm-project/issues/56772>`_ - invalid
- destructor names were incorrectly accepted on template classes.
-- Improve compile-times with large dynamic array allocations with trivial
- constructors. This fixes
- `Issue 56774 <https://github.com/llvm/llvm-project/issues/56774>`_.
-- No longer assert/miscompile when trying to make a vectorized ``_BitInt`` type
- using the ``ext_vector_type`` attribute (the ``vector_size`` attribute was
- already properly diagnosing this case).
-- Fix clang not properly diagnosing the failing subexpression when chained
- binary operators are used in a ``static_assert`` expression.
-- Fix a crash when evaluating a multi-dimensional array's array filler
- expression is element-dependent. This fixes
- `Issue 50601 <https://github.com/llvm/llvm-project/issues/56016>`_.
-- Fixed a crash-on-valid with consteval evaluation of a list-initialized
- constructor for a temporary object. This fixes
- `Issue 55871 <https://github.com/llvm/llvm-project/issues/55871>`_.
-- Fix `#57008 <https://github.com/llvm/llvm-project/issues/57008>`_ - Builtin
- C++ language extension type traits instantiated by a template with unexpected
- number of arguments cause an assertion fault.
-- Fix multi-level pack expansion of undeclared function parameters.
- This fixes `Issue 56094 <https://github.com/llvm/llvm-project/issues/56094>`_.
-- Fix `#57151 <https://github.com/llvm/llvm-project/issues/57151>`_.
- ``-Wcomma`` is emitted for void returning functions.
-- ``-Wtautological-compare`` missed warnings for tautological comparisons
- involving a negative integer literal. This fixes
- `Issue 42918 <https://github.com/llvm/llvm-project/issues/42918>`_.
-- Fix a crash when generating code coverage information for an
- ``if consteval`` statement. This fixes
- `Issue 57377 <https://github.com/llvm/llvm-project/issues/57377>`_.
-- Fix assert that triggers a crash during template name lookup when a type was
- incomplete but was not also a TagType. This fixes
- `Issue 57387 <https://github.com/llvm/llvm-project/issues/57387>`_.
-- Fix a crash when emitting a concept-related diagnostic. This fixes
- `Issue 57415 <https://github.com/llvm/llvm-project/issues/57415>`_.
-- Fix a crash when attempting to default a virtual constexpr non-special member
- function in a derived class. This fixes
- `Issue 57431 <https://github.com/llvm/llvm-project/issues/57431>`_
-- Fix a crash where we attempt to define a deleted destructor. This fixes
- `Issue 57516 <https://github.com/llvm/llvm-project/issues/57516>`_
-- Fix ``__builtin_assume_aligned`` crash when the 1st arg is array type. This fixes
- `Issue 57169 <https://github.com/llvm/llvm-project/issues/57169>`_
-- Clang configuration files are now read through the virtual file system
- rather than the physical one, if these are
diff erent.
-- Clang will now no longer treat a C 'overloadable' function without a prototype as
- a variadic function with the attribute. This should make further diagnostics more
- clear.
-- Fixes to builtin template emulation of regular templates.
- `Issue 42102 <https://github.com/llvm/llvm-project/issues/42102>`_
- `Issue 51928 <https://github.com/llvm/llvm-project/issues/51928>`_
-- A SubstTemplateTypeParmType can now represent the pack index for a
- substitution from an expanded pack.
- `Issue 56099 <https://github.com/llvm/llvm-project/issues/56099>`_
-- Fix `-Wpre-c++17-compat` crashing Clang when compiling C++20 code which
- contains deduced template specializations. This Fixes
- `Issue 57369 <https://github.com/llvm/llvm-project/issues/57369>`_
- `Issue 57643 <https://github.com/llvm/llvm-project/issues/57643>`_
- `Issue 57793 <https://github.com/llvm/llvm-project/issues/57793>`_
-- Respect constructor constraints during class template argument deduction (CTAD).
- This is the suggested resolution to CWG DR2628.
- `Issue 57646 <https://github.com/llvm/llvm-project/issues/57646>`_
- `Issue 43829 <https://github.com/llvm/llvm-project/issues/43829>`_
-- Fixed a crash in C++20 mode in Clang and Clangd when compile source
- with compilation errors.
- `Issue 53628 <https://github.com/llvm/llvm-project/issues/53628>`_
-- The template arguments of a variable template being accessed as a
- member will now be represented in the AST.
-- Fix incorrect handling of inline builtins with asm labels.
-- Finished implementing C++ DR2565, which results in a requirement becoming
- not satisfied in the event of an instantiation failures in a requires expression's
- parameter list. We previously handled this correctly in a constraint evaluation
- context, but not in a requires clause evaluated as a boolean.
-- Address the thread identification problems in coroutines.
- `Issue 47177 <https://github.com/llvm/llvm-project/issues/47177>`_
- `Issue 47179 <https://github.com/llvm/llvm-project/issues/47179>`_
-- Fix a crash upon stray coloncolon token in C2x mode.
-- Reject non-type template arguments formed by casting a non-zero integer
- to a pointer in pre-C++17 modes, instead of treating them as null
- pointers.
-- Fix template arguments of pointer and reference not taking the type as
- part of their identity.
- `Issue 47136 <https://github.com/llvm/llvm-project/issues/47136>`_
-- Fix a crash when trying to form a recovery expression on a call inside a
- constraint, which re-evaluated the same constraint.
- `Issue 53213 <https://github.com/llvm/llvm-project/issues/53213>`_
- `Issue 45736 <https://github.com/llvm/llvm-project/issues/45736>`_
-- Fix an issue when performing constraints partial ordering on non-template
- functions. `Issue 56154 <https://github.com/llvm/llvm-project/issues/56154>`_
-- Fix handling of unexpanded packs in template argument expressions.
- `Issue 58679 <https://github.com/llvm/llvm-project/issues/58679>`_
-- Fix a crash when a ``btf_type_tag`` attribute is applied to the pointee of
- a function pointer.
-- Fix a number of recursively-instantiated constraint issues, which would possibly
- result in a stack overflow.
- `Issue 44304 <https://github.com/llvm/llvm-project/issues/44304>`_
- `Issue 50891 <https://github.com/llvm/llvm-project/issues/50891>`_
-- Clang 14 predeclared some builtin POSIX library functions in ``gnu2x`` mode,
- and Clang 15 accidentally stopped predeclaring those functions in that
- language mode. Clang 16 now predeclares those functions again. This fixes
- `Issue 56607 <https://github.com/llvm/llvm-project/issues/56607>`_.
-- GNU attributes being applied prior to standard attributes would be handled
- improperly, which was corrected to match the behaviour exhibited by GCC.
- `Issue 58229 <https://github.com/llvm/llvm-project/issues/58229>`_
-- The builtin type trait ``__is_aggregate`` now returns ``true`` for arrays of incomplete
- types in accordance with the suggested fix for `LWG3823 <https://cplusplus.github.io/LWG/issue3823>`_
-- Fix bug with using enum that could lead to enumerators being treated as if
- they were part of an overload set. This fixes
- `Issue 58067 <https://github.com/llvm/llvm-project/issues/58057>`_
- `Issue 59014 <https://github.com/llvm/llvm-project/issues/59014>`_
- `Issue 54746 <https://github.com/llvm/llvm-project/issues/54746>`_
-- Fix assert that triggers a crash during some types of list initialization that
- generate a CXXTemporaryObjectExpr instead of a InitListExpr. This fixes
- `Issue 58302 <https://github.com/llvm/llvm-project/issues/58302>`_
- `Issue 58753 <https://github.com/llvm/llvm-project/issues/58753>`_
- `Issue 59100 <https://github.com/llvm/llvm-project/issues/59100>`_
-- Fix issue using __attribute__((format)) on non-variadic functions that expect
- more than one formatted argument.
-- Fix bug where constant evaluation treated a pointer to member that points to
- a weak member as never being null. Such comparisons are now treated as
- non-constant.
-- Fix sanity check when value initializing an empty union so that it takes into
- account anonymous structs which is a GNU extension. This fixes
- `Issue 58800 <https://github.com/llvm/llvm-project/issues/58800>`_
-- Fix an issue that triggers a crash if we instantiate a hidden friend functions.
- This fixes `Issue 54457 <https://github.com/llvm/llvm-project/issues/54457>`_
-- Fix an issue where -frewrite-includes generated line control directives with
- incorrect line numbers in some cases when a header file used an end of line
- character sequence that
diff ered from the primary source file.
- `Issue 59736 <https://github.com/llvm/llvm-project/issues/59736>`_
-- In C mode, when ``e1`` has ``__attribute__((noreturn))`` but ``e2`` doesn't,
- ``(c ? e1 : e2)`` is no longer considered noreturn.
- `Issue 59792 <https://github.com/llvm/llvm-project/issues/59792>`_
-- Fix an issue that makes Clang crash on lambda template parameters. This fixes
- `Issue 57960 <https://github.com/llvm/llvm-project/issues/57960>`_
-- Fix issue that the standard C++ modules importer will call global
- constructor/destructor for the global varaibles in the importing modules.
- This fixes `Issue 59765 <https://github.com/llvm/llvm-project/issues/59765>`_
-- Reject in-class defaulting of previosly declared comparison operators. Fixes
- `Issue 51227 <https://github.com/llvm/llvm-project/issues/51227>`_.
-- Fix the bug of inserting the ``ZeroInitializationFixit`` before the template
- argument list of ``VarTemplateSpecializationDecl``.
+C2x Feature Support
+^^^^^^^^^^^^^^^^^^^
+- Implemented `WG14 N2662 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2662.pdf>`_,
+ so the ``[[maybe_unused]]`` attribute may be applied to a label to silence an
+ ``-Wunused-label`` warning.
+- Implemented `WG14 N2508 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2508.pdf>`_,
+ so labels can placed everywhere inside a compound statement.
+- Implemented `WG14 N2927 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm>`_,
+ the Not-so-magic ``typeof`` operator. Also implemented
+ `WG14 N2930 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2930.pdf>`_,
+ renaming ``remove_quals``, so the ``typeof_unqual`` operator is also
+ supported. Both of these operators are supported only in C2x mode. The
+ ``typeof`` operator specifies the type of the given parenthesized expression
+ operand or type name, including all qualifiers. The ``typeof_unqual``
+ operator is similar to ``typeof`` except that all qualifiers are removed,
+ including atomic type qualification and type attributes which behave like a
+ qualifier, such as an address space attribute.
-Improvements to Clang's diagnostics
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-- Disabled FIT-IT suggested for a case of bad conversion in system headers.
-- Clang will now check compile-time determinable string literals as format strings.
- Fixes `Issue 55805: <https://github.com/llvm/llvm-project/issues/55805>`_.
-- ``-Wformat`` now recognizes ``%b`` for the ``printf``/``scanf`` family of
- functions and ``%B`` for the ``printf`` family of functions. Fixes
- `Issue 56885: <https://github.com/llvm/llvm-project/issues/56885>`_.
-- Introduced ``-Wsingle-bit-bitfield-constant-conversion``, grouped under
- ``-Wbitfield-constant-conversion``, which diagnoses implicit truncation when
- ``1`` is assigned to a 1-bit signed integer bitfield. This fixes
- `Issue 53253 <https://github.com/llvm/llvm-project/issues/53253>`_. To reduce
- potential false positives, this diagnostic will not diagnose use of the
- ``true`` macro (from ``<stdbool.h>>`) in C language mode despite the macro
- being defined to expand to ``1``.
-- Clang will now print more information about failed static assertions. In
- particular, simple static assertion expressions are evaluated to their
- compile-time value and printed out if the assertion fails.
-- Diagnostics about uninitialized ``constexpr`` varaibles have been improved
- to mention the missing constant initializer.
-- Correctly diagnose a future keyword if it exist as a keyword in the higher
- language version and specifies in which version it will be a keyword. This
- supports both c and c++ language.
-- When diagnosing multi-level pack expansions of mismatched lengths, Clang will
- now, in most cases, be able to point to the relevant outer parameter.
-- ``no_sanitize("...")`` on a global variable for known but not relevant
- sanitizers is now just a warning. It now says that this will be ignored
- instead of incorrectly saying no_sanitize only applies to functions and
- methods.
-- No longer mention ``reinterpet_cast`` in the invalid constant expression
- diagnostic note when in C mode.
-- Clang will now give a more suitale diagnostic for declaration of block
- scope identifiers that have external/internal linkage that has an initializer.
- Fixes `Issue 57478: <https://github.com/llvm/llvm-project/issues/57478>`_.
-- New analysis pass will now help preserve sugar when combining deductions, in an
- order agnostic way. This will be in effect when deducing template arguments,
- when deducing function return type from multiple return statements, for the
- conditional operator, and for most binary operations. Type sugar is combined
- in a way that strips the sugar which is
diff erent between terms, and preserves
- those which are common.
-- Correctly diagnose use of an integer literal without a suffix whose
- underlying type is ``long long`` or ``unsigned long long`` as an extension in
- C89 mode . Clang previously only diagnosed if the literal had an explicit
- ``LL`` suffix.
-- Clang now correctly diagnoses index that refers past the last possible element
- of FAM-like arrays.
-- Clang now correctly diagnoses a warning when defercencing a void pointer in C mode.
- This fixes `Issue 53631 <https://github.com/llvm/llvm-project/issues/53631>`_
-- Clang will now diagnose an overload set where a candidate has a constraint that
- refers to an expression with a previous error as nothing viable, so that it
- doesn't generate strange cascading errors, particularly in cases where a
- subsuming constraint fails, which would result in a less-specific overload to
- be selected.
-- Add a fix-it hint for the ``-Wdefaulted-function-deleted`` warning to
- explicitly delete the function.
-- Fixed an accidental duplicate diagnostic involving the declaration of a
- function definition without a prototype which is preceded by a static
- declaration of the function with a prototype. Fixes
- `Issue 58181 <https://github.com/llvm/llvm-project/issues/58181>`_.
-- Copy-elided initialization of lock scopes is now handled
diff erently in
- ``-Wthread-safety-analysis``: annotations on the move constructor are no
- longer taken into account, in favor of annotations on the function returning
- the lock scope by value. This could result in new warnings if code depended
- on the previous undocumented behavior. As a side effect of this change,
- constructor calls outside of initializer expressions are no longer ignored,
- which can result in new warnings (or make existing warnings disappear).
-- The wording of diagnostics regarding arithmetic on fixed-sized arrays and
- pointers is improved to include the type of the array and whether it's cast
- to another type. This should improve comprehension for why an index is
- out-of-bounds.
-- Clang now correctly points to the problematic parameter for the ``-Wnonnull``
- warning. This fixes
- `Issue 58273 <https://github.com/llvm/llvm-project/issues/58273>`_.
-- Introduced ``-Wcast-function-type-strict`` and
- ``-Wincompatible-function-pointer-types-strict`` to warn about function type
- mismatches in casts and assignments that may result in runtime indirect call
- `Control-Flow Integrity (CFI)
- <https://clang.llvm.org/docs/ControlFlowIntegrity.html>`_ failures. The
- ``-Wcast-function-type-strict`` diagnostic is grouped under
- ``-Wcast-function-type`` as it identifies a more strict set of potentially
- problematic function type casts.
-- Clang will now disambiguate NTTP types when printing diagnostic that contain NTTP types.
- Fixes `Issue 57562 <https://github.com/llvm/llvm-project/issues/57562>`_.
-- Better error recovery for pack expansion of expressions.
- `Issue 58673 <https://github.com/llvm/llvm-project/issues/58673>`_.
-- Better diagnostics when the user has missed `auto` in a declaration.
- `Issue 49129 <https://github.com/llvm/llvm-project/issues/49129>`_.
-- Clang now diagnoses use of invalid or reserved module names in a module
- export declaration. Both are diagnosed as an error, but the diagnostic is
- suppressed for use of reserved names in a system header.
-- ``-Winteger-overflow`` will diagnose overflow in more cases. This fixes
- `Issue 58944 <https://github.com/llvm/llvm-project/issues/58944>`_.
-- Clang has an internal limit of 2GB of preprocessed source code per
- compilation, including source reachable through imported AST files such as
- PCH or modules. When Clang hits this limit, it now produces notes mentioning
- which header and source files are consuming large amounts of this space.
- ``#pragma clang __debug sloc_usage`` can also be used to request this report.
-- Clang no longer permits the keyword 'bool' in a concept declaration as a
- concepts-ts compatibility extension.
-- Clang now diagnoses overflow undefined behavior in a constant expression while
- evaluating a compound assignment with remainder as operand.
-- Add ``-Wreturn-local-addr``, a GCC alias for ``-Wreturn-stack-address``.
-- Clang now suppresses ``-Wlogical-op-parentheses`` on ``(x && a || b)`` and ``(a || b && x)``
- only when ``x`` is a string literal.
-- Clang will now reject the GNU extension address of label in coroutines explicitly.
- This fixes `Issue 56436 <https://github.com/llvm/llvm-project/issues/56436>`_.
-- Clang now automatically adds ``[[clang::lifetimebound]]`` to the parameters of
- ``std::move, std::forward`` et al, this enables Clang to diagnose more cases
- where the returned reference outlives the object.
+ .. code-block:: c
+
+ __attribute__((address_space(1))) const _Atomic int Val;
+ typeof(Val) OtherVal; // type is '__attribute__((address_space(1))) const _Atomic int'
+ typeof_unqual(Val) OtherValUnqual; // type is 'int'
+
+- Implemented `WG14 N3042 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3042.htm>`_,
+ Introduce the nullptr constant. This introduces a new type ``nullptr_t``,
+ declared in ``<stddef.h>`` which represents the type of the null pointer named
+ constant, ``nullptr``. This constant is implicitly convertible to any pointer
+ type and represents a type-safe null value.
+
+ Note, there are some known incompatibilities with this same feature in C++.
+ The following examples were discovered during implementation and are subject
+ to change depending on how national body comments are resolved by WG14 (C
+ status is based on standard requirements, not necessarily implementation
+ behavior):
+
+ .. code-block:: c
+
+ nullptr_t null_val;
+ (nullptr_t)nullptr; // Rejected in C, accepted in C++, Clang accepts
+ (void)(1 ? nullptr : 0); // Rejected in C, accepted in C++, Clang rejects
+ (void)(1 ? null_val : 0); // Rejected in C, accepted in C++, Clang rejects
+ bool b1 = nullptr; // Accepted in C, rejected in C++, Clang rejects
+ b1 = null_val; // Accepted in C, rejected in C++, Clang rejects
+ null_val = 0; // Rejected in C, accepted in C++, Clang rejects
+
+ void func(nullptr_t);
+ func(0); // Rejected in C, accepted in C++, Clang rejects
+
+- Implemented `WG14 N2975 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2975.pdf>`_,
+ Relax requirements for va_start. In C2x mode, functions can now be declared
+ fully variadic and the ``va_start`` macro no longer requires passing a second
+ argument (though it accepts a second argument for backwards compatibility).
+ If a second argument is passed, it is neither expanded nor evaluated in C2x
+ mode.
+
+ .. code-block:: c
+
+ void func(...) { // Invalid in C17 and earlier, valid in C2x and later.
+ va_list list;
+ va_start(list); // Invalid in C17 and earlier, valid in C2x and later.
+ va_end(list);
+ }
+
+- Diagnose type definitions in the ``type`` argument of ``__builtin_offsetof``
+ as a conforming C extension according to
+ `WG14 N2350 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm>`_.
+ Also documents the builtin appropriately. Note, a type definition in C++
+ continues to be rejected.
Non-comprehensive list of changes in this release
-------------------------------------------------
- It's now possible to set the crash diagnostics directory through
the environment variable ``CLANG_CRASH_DIAGNOSTICS_DIR``.
The ``-fcrash-diagnostics-dir`` flag takes precedence.
-- When using header modules, inclusion of a private header and violations of
- the `use-declaration rules
- <https://clang.llvm.org/docs/Modules.html#use-declaration>`_ are now
- diagnosed even when the includer is a textual header. This change can be
- temporarily reversed with ``-Xclang
- -fno-modules-validate-textual-header-includes``, but this flag will be
- removed in a future Clang release.
+
- Unicode support has been updated to support Unicode 15.0.
New unicode codepoints are supported as appropriate in diagnostics,
C and C++ identifiers, and escape sequences.
+
- In identifiers, Clang allows a restricted set of additional mathematical symbols
as an extension. These symbols correspond to a proposed Unicode
`Mathematical notation profile for default identifiers
<https://www.unicode.org/L2/L2022/22230-math-profile.pdf>`_.
- This resolves `Issue 54732 <https://github.com/llvm/llvm-project/issues/54732>`_.
+ (`#54732 <https://github.com/llvm/llvm-project/issues/54732>`_)
+
- Clang now supports loading multiple configuration files. The files from
default configuration paths are loaded first, unless ``--no-default-config``
option is used. All files explicitly specified using ``--config=`` option
are loaded afterwards.
+
- When loading default configuration files, clang now unconditionally uses
the real target triple (respecting options such as ``--target=`` and ``-m32``)
rather than the executable prefix. The respective configuration files are
also loaded when clang is called via an executable without a prefix (e.g.
plain ``clang``).
+
- Default configuration paths were partially changed. Clang now attempts to load
``<triple>-<driver>.cfg`` first, and falls back to loading both
``<driver>.cfg`` and ``<triple>.cfg`` if the former is not found. `Triple`
is the target triple and `driver` first tries the canonical name
for the driver (respecting ``--driver-mode=``), and then the name found
in the executable.
+
- If the environment variable ``SOURCE_DATE_EPOCH`` is set, it specifies a UNIX
timestamp to be used in replacement of the current date and time in
the ``__DATE__``, ``__TIME__``, and ``__TIMESTAMP__`` macros. See
`<https://reproducible-builds.org/docs/source-date-epoch/>`_.
+
- Clang now supports ``__has_constexpr_builtin`` function-like macro that
evaluates to 1 if the builtin is supported and can be constant evaluated.
It can be used to writing conditionally constexpr code that uses builtins.
+
- The time profiler (using ``-ftime-trace`` option) now traces various constant
evaluation events.
+
- Clang can now generate a PCH when using ``-fdelayed-template-parsing`` for
code with templates containing loop hint pragmas, OpenMP pragmas, and
``#pragma unused``.
-- Now diagnoses use of a member access expression or array subscript expression
- within ``__builtin_offsetof`` and ``offsetof`` as being a Clang extension.
New Compiler Flags
------------------
-- Implemented `-fcoro-aligned-allocation` flag. This flag implements
+- Implemented ``-fcoro-aligned-allocation`` flag. This flag implements
Option 2 of P2014R0 aligned allocation of coroutine frames
(`P2014R0 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2014r0.pdf>`_).
With this flag, the coroutines will try to lookup aligned allocation
@@ -528,8 +456,8 @@ New Compiler Flags
find aligned allocation function. So if the user code implemented self
defined allocation function for coroutines, the existing code will be
broken. A little divergence with P2014R0 is that clang will lookup
- `::operator new(size_t, std::aligned_val_t, nothrow_t)` if there is
- `get_return_object_on_allocation_failure`. We feel this is more consistent
+ ``::operator new(size_t, std::aligned_val_t, nothrow_t)`` if there is
+ ``get_return_object_on_allocation_failure``. We feel this is more consistent
with the intention.
- Added ``--no-default-config`` to disable automatically loading configuration
@@ -588,10 +516,6 @@ Removed Compiler Flags
- Clang now no longer supports ``-cc1 -fconcepts-ts``. This flag has been deprecated
and encouraged use of ``-std=c++20`` since Clang 10, so we're now removing it.
-New Pragmas in Clang
---------------------
-- ...
-
Attribute Changes in Clang
--------------------------
- Added support for ``__attribute__((guard(nocf)))`` and C++-style
@@ -628,274 +552,392 @@ Attribute Changes in Clang
<https://clang.llvm.org/docs/AttributeReference.html#target-version>`_ for
more details.
-Windows Support
----------------
-- For the MinGW driver, added the options ``-mguard=none``, ``-mguard=cf`` and
- ``-mguard=cf-nochecks`` (equivalent to ``/guard:cf-``, ``/guard:cf`` and
- ``/guard:cf,nochecks`` in clang-cl) for enabling Control Flow Guard checks
- and generation of address-taken function table.
+Improvements to Clang's diagnostics
+-----------------------------------
+- Disabled a FIX-IT suggested for a case of bad conversion in system headers.
-- Switched from SHA1 to BLAKE3 for PDB type hashing / ``-gcodeview-ghash``
+- Clang will now check compile-time determinable string literals as format strings.
+ (`#55805 <https://github.com/llvm/llvm-project/issues/55805>`_)
-- Fixed code generation with emulated TLS, when the emulated TLS is enabled
- by default (with downstream patches; no upstream configurations default
- to this configuration, but some mingw downstreams change the default
- in this way).
+- ``-Wformat`` now recognizes ``%b`` for the ``printf``/``scanf`` family of
+ functions and ``%B`` for the ``printf`` family of functions.
+ (`#56885 <https://github.com/llvm/llvm-project/issues/56885>`_)
-- Improved detection of MinGW cross sysroots for finding sysroots provided
- by Linux distributions such as Fedora. Also improved such setups by
- avoiding to include ``/usr/include`` among the include paths when cross
- compiling with a cross sysroot based in ``/usr``.
+- Introduced ``-Wsingle-bit-bitfield-constant-conversion``, grouped under
+ ``-Wbitfield-constant-conversion``, which diagnoses implicit truncation when
+ ``1`` is assigned to a 1-bit signed integer bitfield. To reduce
+ potential false positives, this diagnostic will not diagnose use of the
+ ``true`` macro (from ``<stdbool.h>``) in C language mode despite the macro
+ being defined to expand to ``1``. (`#53253 <https://github.com/llvm/llvm-project/issues/53253>`_)
-AIX Support
------------
-* When using ``-shared``, the clang driver now invokes llvm-nm to create an
- export list if the user doesn't specify one via linker flag or pass an
- alternative export control option.
+- Clang will now print more information about failed static assertions. In
+ particular, simple static assertion expressions are evaluated to their
+ compile-time value and printed out if the assertion fails.
-C Language Changes in Clang
----------------------------
-- Adjusted ``-Wformat`` warnings according to `WG14 N2562 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2562.pdf>`_.
- Clang will now consider default argument promotions in ``printf``, and remove
- unnecessary warnings. Especially ``int`` argument with specifier ``%hhd`` and
- ``%hd``.
+- Diagnostics about uninitialized ``constexpr`` variables have been improved
+ to mention the missing constant initializer.
-C2x Feature Support
--------------------
-- Implemented `WG14 N2662 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2662.pdf>`_,
- so the [[maybe_unused]] attribute may be applied to a label to silence an
- ``-Wunused-label`` warning.
-- Implemented `WG14 N2508 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2508.pdf>`_,
- so labels can placed everywhere inside a compound statement.
-- Implemented `WG14 N2927 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm>`_,
- the Not-so-magic ``typeof`` operator. Also implemented
- `WG14 N2930 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2930.pdf>`_,
- renaming ``remove_quals``, so the ``typeof_unqual`` operator is also
- supported. Both of these operators are supported only in C2x mode. The
- ``typeof`` operator specifies the type of the given parenthesized expression
- operand or type name, including all qualifiers. The ``typeof_unqual``
- operator is similar to ``typeof`` except that all qualifiers are removed,
- including atomic type qualification and type attributes which behave like a
- qualifier, such as an address space attribute.
+- Correctly diagnose a future keyword if it exists as a keyword in the higher
+ language version and specifies in which version it will be a keyword. This
+ supports both C and C++.
- .. code-block:: c
+- When diagnosing multi-level pack expansions of mismatched lengths, Clang will
+ now, in most cases, be able to point to the relevant outer parameter.
+
+- ``no_sanitize("...")`` on a global variable for known but not relevant
+ sanitizers is now just a warning. It now says that this will be ignored
+ instead of incorrectly saying no_sanitize only applies to functions and
+ methods.
+
+- No longer mention ``reinterpet_cast`` in the invalid constant expression
+ diagnostic note when in C mode.
+
+- Clang will now give a more suitale diagnostic for declaration of block
+ scope identifiers that have external/internal linkage that has an initializer.
+ (`#57478 <https://github.com/llvm/llvm-project/issues/57478>`_)
+
+- A new analysis pass will helps preserve sugar when combining deductions, in an
+ order agnostic way. This will be in effect when deducing template arguments,
+ when deducing function return type from multiple return statements, for the
+ conditional operator, and for most binary operations. Type sugar is combined
+ in a way that strips the sugar which is
diff erent between terms, and preserves
+ those which are common.
+
+- Correctly diagnose the use of an integer literal without a suffix whose
+ underlying type is ``long long`` or ``unsigned long long`` as an extension in
+ C89 mode . Clang previously only diagnosed if the literal had an explicit
+ ``LL`` suffix.
+
+- Clang now correctly diagnoses index that refers past the last possible element
+ of FAM-like arrays.
+
+- Clang now correctly emits a warning when dereferencing a void pointer in C mode.
+ (`#53631 <https://github.com/llvm/llvm-project/issues/53631>`_)
+
+- Clang will now diagnose an overload set where a candidate has a constraint that
+ refers to an expression with a previous error as nothing viable, so that it
+ doesn't generate strange cascading errors, particularly in cases where a
+ subsuming constraint fails, which would result in a less-specific overload to
+ be selected.
+
+- Add a fix-it hint for the ``-Wdefaulted-function-deleted`` warning to
+ explicitly delete the function.
+
+- Fixed an accidental duplicate diagnostic involving the declaration of a
+ function definition without a prototype which is preceded by a static
+ declaration of the function with a prototype.
+ (`#58181 <https://github.com/llvm/llvm-project/issues/58181>`_)
+
+- Copy-elided initialization of lock scopes is now handled
diff erently in
+ ``-Wthread-safety-analysis``: annotations on the move constructor are no
+ longer taken into account, in favor of annotations on the function returning
+ the lock scope by value. This could result in new warnings if code depended
+ on the previous undocumented behavior. As a side effect of this change,
+ constructor calls outside of initializer expressions are no longer ignored,
+ which can result in new warnings (or make existing warnings disappear).
+
+- The wording of diagnostics regarding arithmetic on fixed-sized arrays and
+ pointers is improved to include the type of the array and whether it's cast
+ to another type. This should improve comprehension for why an index is
+ out-of-bounds.
+
+- Clang now correctly points to the problematic parameter for the ``-Wnonnull``
+ warning. (`#58273 <https://github.com/llvm/llvm-project/issues/58273>`_)
+
+- Introduced ``-Wcast-function-type-strict`` and
+ ``-Wincompatible-function-pointer-types-strict`` to warn about function type
+ mismatches in casts and assignments that may result in runtime indirect call
+ `Control-Flow Integrity (CFI)
+ <https://clang.llvm.org/docs/ControlFlowIntegrity.html>`_ failures. The
+ ``-Wcast-function-type-strict`` diagnostic is grouped under
+ ``-Wcast-function-type`` as it identifies a more strict set of potentially
+ problematic function type casts.
+
+- Clang will now disambiguate NTTP types when printing diagnostic that contain NTTP types.
+ (`#57562 <https://github.com/llvm/llvm-project/issues/57562>`_)
+
+- Better error recovery for pack expansion of expressions.
+ (`#58673 <https://github.com/llvm/llvm-project/issues/58673>`_)
+
+- Better diagnostics when the user has missed ``auto`` in a declaration.
+ (`#49129 <https://github.com/llvm/llvm-project/issues/49129>`_)
+
+- Clang now diagnoses use of invalid or reserved module names in a module
+ export declaration. Both are diagnosed as an error, but the diagnostic is
+ suppressed for use of reserved names in a system header.
+
+- ``-Winteger-overflow`` will diagnose overflow in more cases.
+ (`#58944 <https://github.com/llvm/llvm-project/issues/58944>`_)
+
+- Clang has an internal limit of 2GB of preprocessed source code per
+ compilation, including source reachable through imported AST files such as
+ PCH or modules. When Clang hits this limit, it now produces notes mentioning
+ which header and source files are consuming large amounts of this space.
+ ``#pragma clang __debug sloc_usage`` can also be used to request this report.
+
+- Clang no longer permits the keyword 'bool' in a concept declaration as a
+ concepts-ts compatibility extension.
+
+- Clang now diagnoses overflow undefined behavior in a constant expression while
+ evaluating a compound assignment with remainder as operand.
+
+- Add ``-Wreturn-local-addr``, a GCC alias for ``-Wreturn-stack-address``.
+
+- Clang now suppresses ``-Wlogical-op-parentheses`` on ``(x && a || b)`` and ``(a || b && x)``
+ only when ``x`` is a string literal.
+
+- Clang will now reject the GNU extension address of label in coroutines explicitly.
+ (`#56436 <https://github.com/llvm/llvm-project/issues/56436>`_)
+
+- Clang now automatically adds ``[[clang::lifetimebound]]`` to the parameters of
+ ``std::move, std::forward`` et al, this enables Clang to diagnose more cases
+ where the returned reference outlives the object.
+
+- Fix clang not properly diagnosing the failing subexpression when chained
+ binary operators are used in a ``static_assert`` expression.
+
+- ``-Wtautological-compare`` missed warnings for tautological comparisons
+ involving a negative integer literal.
+ (`#42918 <https://github.com/llvm/llvm-project/issues/42918>`_)
+
+- ``-Wcomma`` is no longer emitted for void returning functions.
+ (`#57151 <https://github.com/llvm/llvm-project/issues/57151>`_)
+
+Bug Fixes in This Version
+-------------------------
+
+Bug Fixes to Compiler Builtins
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- ``stdatomic.h`` will use the internal declarations when targeting pre-C++-23
+ on Windows platforms as the MSVC support requires newer C++ standard.
+
+- Correct ``_Static_assert`` to accept the same set of extended integer
+ constant expressions as is accpted in other contexts that accept them.
+ (`#57687 <https://github.com/llvm/llvm-project/issues/57687>`_)
+
+- Fix crashes caused when builtin C++ language extension type traits were
+ instantiated by templates with an unexpected number of arguments.
+ (`#57008 <https://github.com/llvm/llvm-project/issues/57008>`_)
+
+- Fix ``__builtin_assume_aligned`` crash when the 1st arg is array type.
+ (`#57169 <https://github.com/llvm/llvm-project/issues/57169>`_)
+
+- Fixes to builtin template emulation of regular templates.
+ (`#42102 <https://github.com/llvm/llvm-project/issues/42102>`_,
+ `#51928 <https://github.com/llvm/llvm-project/issues/51928>`_)
+
+- Fix incorrect handling of inline builtins with asm labels.
+
+- The builtin type trait ``__is_aggregate`` now returns ``true`` for arrays of incomplete
+ types in accordance with the suggested fix for `LWG3823 <https://cplusplus.github.io/LWG/issue3823>`_
+
+Bug Fixes to Attribute Support
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Fixes an accepts-invalid bug in C when using a ``_Noreturn`` function
+ specifier on something other than a function declaration.
+ (`#56800 <https://github.com/llvm/llvm-project/issues/56800>`_)
+
+- No longer assert/miscompile when trying to make a vectorized ``_BitInt`` type
+ using the ``ext_vector_type`` attribute (the ``vector_size`` attribute was
+ already properly diagnosing this case).
+
+- Invalid destructor names are no longer accepted on template classes.
+ (`#56772 <https://github.com/llvm/llvm-project/issues/56772>`_)
+
+- Improve compile-times with large dynamic array allocations with trivial
+ constructors.
+ (`#56774 <https://github.com/llvm/llvm-project/issues/56774>`_)
+
+- Fix a crash when a ``btf_type_tag`` attribute is applied to the pointee of
+ a function pointer.
+
+- In C mode, when ``e1`` has ``__attribute__((noreturn))`` but ``e2`` doesn't,
+ ``(c ? e1 : e2)`` is no longer considered noreturn.
+ (`#59792 <https://github.com/llvm/llvm-project/issues/59792>`_)
+
+- GNU attributes being applied prior to standard attributes would be handled
+ improperly, which was corrected to match the behaviour exhibited by GCC.
+ (`#58229 <https://github.com/llvm/llvm-project/issues/58229>`_)
+
+- Fix issue using __attribute__((format)) on non-variadic functions that expect
+ more than one formatted argument.
+
+- Clang will now no longer treat a C 'overloadable' function without a prototype as
+ a variadic function with the attribute. This should make further diagnostics more
+ clear.
+
+Bug Fixes to C++ Support
+^^^^^^^^^^^^^^^^^^^^^^^^
+- Fix multi-level pack expansion of undeclared function parameters.
+ (`#56094 <https://github.com/llvm/llvm-project/issues/56094>`_)
+
+- Address the thread identification problems in coroutines.
+ (`#47177 <https://github.com/llvm/llvm-project/issues/47177>`_,
+ `#47179 <https://github.com/llvm/llvm-project/issues/47179>`_)
+
+- Reject non-type template arguments formed by casting a non-zero integer
+ to a pointer in pre-C++17 modes, instead of treating them as null
+ pointers.
+
+- Fix template arguments of pointer and reference not taking the type as
+ part of their identity.
+ (`#47136 <https://github.com/llvm/llvm-project/issues/47136>`_)
+
+- Fix handling of unexpanded packs in template argument expressions.
+ (`#58679 <https://github.com/llvm/llvm-project/issues/58679>`_)
+
+- Fix bug with ``using enum`` that could lead to enumerators being treated as if
+ they were part of an overload set.
+ (`#58067 <https://github.com/llvm/llvm-project/issues/58057>`_,
+ `#59014 <https://github.com/llvm/llvm-project/issues/59014>`_,
+ `#54746 <https://github.com/llvm/llvm-project/issues/54746>`_)
+
+- Fix bug where constant evaluation treated a pointer to member that points to
+ a weak member as never being null. Such comparisons are now treated as
+ non-constant.
+
+- Fix issue that the standard C++ modules importer will call global
+ constructor/destructor for the global variables in the importing modules.
+ (`#59765 <https://github.com/llvm/llvm-project/issues/59765>`_)
+
+- Reject in-class defaulting of previously declared comparison operators.
+ (`#51227 <https://github.com/llvm/llvm-project/issues/51227>`_)
+
+- Do not hide templated base members introduced via using-decl in derived class
+ (useful specially for constrained members). (`#50886 <https://github.com/llvm/llvm-project/issues/50886>`_)
+
+Concepts Specific Fixes:
+
+- Class member variables are now in scope when parsing a ``requires`` clause.
+ (`#55216 <https://github.com/llvm/llvm-project/issues/55216>`_)
+
+- Required parameter pack to be provided at the end of the concept parameter list.
+ (`#48182 <https://github.com/llvm/llvm-project/issues/48182>`_)
- __attribute__((address_space(1))) const _Atomic int Val;
- typeof(Val) OtherVal; // type is '__attribute__((address_space(1))) const _Atomic int'
- typeof_unqual(Val) OtherValUnqual; // type is 'int'
+- Correctly handle access-checks in requires expression. (`#53364 <https://github.com/llvm/llvm-project/issues/53364>`_,
+ `#53334 <https://github.com/llvm/llvm-project/issues/53334>`_)
-- Implemented `WG14 N3042 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3042.htm>`_,
- Introduce the nullptr constant. This introduces a new type ``nullptr_t``,
- declared in ``<stddef.h>`` which represents the type of the null pointer named
- constant, ``nullptr``. This constant is implicitly convertible to any pointer
- type and represents a type-safe null value.
+- Fixed an issue with concept requirement evaluation, where we incorrectly allowed implicit
+ conversions to bool for a requirement. (`#54524 <https://github.com/llvm/llvm-project/issues/54524>`_)
- Note, there are some known incompatibilities with this same feature in C++.
- The following examples were discovered during implementation and are subject
- to change depending on how national body comments are resolved by WG14 (C
- status is based on standard requirements, not necessarily implementation
- behavior):
+- Respect constructor constraints during class template argument deduction (CTAD).
+ This is the suggested resolution to CWG DR2628.
+ (`#57646 <https://github.com/llvm/llvm-project/issues/57646>`_,
+ `#43829 <https://github.com/llvm/llvm-project/issues/43829>`_)
- .. code-block:: c
+- Fix a crash when emitting a concept-related diagnostic.
+ (`#57415 <https://github.com/llvm/llvm-project/issues/57415>`_)
- nullptr_t null_val;
- (nullptr_t)nullptr; // Rejected in C, accepted in C++, Clang accepts
- (void)(1 ? nullptr : 0); // Rejected in C, accepted in C++, Clang rejects
- (void)(1 ? null_val : 0); // Rejected in C, accepted in C++, Clang rejects
- bool b1 = nullptr; // Accepted in C, rejected in C++, Clang rejects
- b1 = null_val; // Accepted in C, rejected in C++, Clang rejects
- null_val = 0; // Rejected in C, accepted in C++, Clang rejects
+- Fix a crash when trying to form a recovery expression on a call inside a
+ constraint, which re-evaluated the same constraint.
+ (`#53213 <https://github.com/llvm/llvm-project/issues/53213>`_,
+ `#45736 <https://github.com/llvm/llvm-project/issues/45736>`_)
- void func(nullptr_t);
- func(0); // Rejected in C, accepted in C++, Clang rejects
+- Fix an issue when performing constraints partial ordering on non-template
+ functions. (`#56154 <https://github.com/llvm/llvm-project/issues/56154>`_)
-- Implemented `WG14 N2975 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2975.pdf>`_,
- Relax requirements for va_start. In C2x mode, functions can now be declared
- fully variadic and the ``va_start`` macro no longer requires passing a second
- argument (though it accepts a second argument for backwards compatibility).
- If a second argument is passed, it is neither expanded nor evaluated in C2x
- mode.
+- Fix a number of recursively-instantiated constraint issues, which would possibly
+ result in a stack overflow.
+ (`#44304 <https://github.com/llvm/llvm-project/issues/44304>`_,
+ `#50891 <https://github.com/llvm/llvm-project/issues/50891>`_)
- .. code-block:: c
+- Finished implementing C++ DR2565, which results in a requirement becoming
+ not satisfied in the event of an instantiation failures in a requires expression's
+ parameter list. We previously handled this correctly in a constraint evaluation
+ context, but not in a requires clause evaluated as a boolean.
- void func(...) { // Invalid in C17 and earlier, valid in C2x and later.
- va_list list;
- va_start(list); // Invalid in C17 and earlier, valid in C2x and later.
- va_end(list);
- }
+Consteval Specific Fixes:
-- Diagnose type definitions in the ``type`` argument of ``__builtin_offsetof``
- as a conforming C extension according to
- `WG14 N2350 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm>`_.
- Also documents the builtin appropriately. Note, a type definition in C++
- continues to be rejected.
+- Fix a crash when generating code coverage information for an
+ ``if consteval`` statement.
+ (`#57377 <https://github.com/llvm/llvm-project/issues/57377>`_)
-C++ Language Changes in Clang
------------------------------
-- Implemented `DR692 <https://wg21.link/cwg692>`_, `DR1395 <https://wg21.link/cwg1395>`_,
- and `DR1432 <https://wg21.link/cwg1432>`_. The fix for DR1432 is speculative since the
- issue is still open and has no proposed resolution at this time. A speculative fix
- for DR1432 is needed to prevent regressions that would otherwise occur due to 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.
-- Implemented DR2358 allowing init captures in lambdas in default arguments.
-- implemented `DR2654 <https://wg21.link/cwg2654>`_ which undeprecates
- all compound assignements operations on volatile qualified variables.
-- Implemented DR2631. Invalid ``consteval`` calls in default arguments and default
- member initializers are diagnosed when and if the default is used.
- This Fixes `Issue 56379 <https://github.com/llvm/llvm-project/issues/56379>`_
- and changes the value of ``std::source_location::current()``
- used in default parameters calls compared to previous versions of Clang.
+- Fixed a crash-on-valid with consteval evaluation of a list-initialized
+ constructor for a temporary object.
+ (`#55871 <https://github.com/llvm/llvm-project/issues/55871>`_)
-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>`_).
-- Implemented `P2113R0: Proposed resolution for 2019 comment CA 112 <https://wg21.link/P2113R0>`_
- ([temp.func.order]p6.2.1 is not implemented, matching GCC).
-- Implemented `P0857R0 <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0857r0.html>`_,
- which specifies constrained lambdas and constrained template *template-parameter*\s.
-- Required parameter pack to be provided at the end of the concept parameter list. This
- fixes `Issue 48182 <https://github.com/llvm/llvm-project/issues/48182>`_.
+ virtual functions. (`#55065 <https://github.com/llvm/llvm-project/issues/55065>`_)
-- Do not hide templated base members introduced via using-decl in derived class
- (useful specially for constrained members). Fixes `GH50886 <https://github.com/llvm/llvm-project/issues/50886>`_.
-- Implemented CWG2635 as a Defect Report, which prohibits structured bindings from being constrained.
-- Correctly handle access-checks in requires expression. Fixes `GH53364 <https://github.com/llvm/llvm-project/issues/53364>`_,
- `GH53334 <https://github.com/llvm/llvm-project/issues/53334>`_.
+Bug Fixes to AST Handling
+^^^^^^^^^^^^^^^^^^^^^^^^^
+- A SubstTemplateTypeParmType can now represent the pack index for a
+ substitution from an expanded pack.
+ (`#56099 <https://github.com/llvm/llvm-project/issues/56099>`_)
-- Implemented `P0960R3: <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0960r3.html>`_
- and `P1975R0: <https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1975r0.html>`_,
- which allows parenthesized aggregate-initialization.
+- The template arguments of a variable template being accessed as a
+ member will now be represented in the AST.
-- Fixed an issue with concept requirement evaluation, where we incorrectly allowed implicit
- conversions to bool for a requirement. This fixes `GH54524 <https://github.com/llvm/llvm-project/issues/54524>`_.
+Miscellaneous Bug Fixes
+^^^^^^^^^^^^^^^^^^^^^^^
+- Clang configuration files are now read through the virtual file system
+ rather than the physical one, if these are
diff erent.
-C++2b Feature Support
-^^^^^^^^^^^^^^^^^^^^^
+- Fix an issue where -frewrite-includes generated line control directives with
+ incorrect line numbers in some cases when a header file used an end of line
+ character sequence that
diff ered from the primary source file.
+ (`#59736 <https://github.com/llvm/llvm-project/issues/59736>`_)
-- Support label at end of compound statement (`P2324 <https://wg21.link/p2324r2>`_).
-- Implemented `P1169R4: static operator() <https://wg21.link/P1169R4>`_ and `P2589R1: static operator[] <https://wg21.link/P2589R1>`_.
-- Implemented "char8_t Compatibility and Portability Fix" (`P2513R3 <https://wg21.link/P2513R3>`_).
- This change was applied to C++20 as a Defect Report.
-- Implemented "Permitting static constexpr variables in constexpr functions" (`P2647R1 <https://wg21.link/P2647R1>_`).
-- Implemented `CWG2640 Allow more characters in an n-char sequence <https://wg21.link/CWG2640>_`.
+- Clang 14 predeclared some builtin POSIX library functions in ``gnu2x`` mode,
+ and Clang 15 accidentally stopped predeclaring those functions in that
+ language mode. Clang 16 now predeclares those functions again.
+ (`#56607 <https://github.com/llvm/llvm-project/issues/56607>`_)
-CUDA/HIP Language Changes in Clang
-----------------------------------
+- Fix the bug of inserting the ``ZeroInitializationFixit`` before the template
+ argument list of ``VarTemplateSpecializationDecl``.
- - Allow the use of ``__noinline__`` as a keyword (instead of ``__attribute__((noinline))``)
- in lambda declarations.
+Miscellaneous Clang Crashes Fixed
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Fix a crash when evaluating a multi-dimensional array's array filler
+ expression is element-dependent.
+ (`#50601 <https://github.com/llvm/llvm-project/issues/56016>`_)
-Objective-C Language Changes in Clang
--------------------------------------
+- Fix an assert that triggers a crash during template name lookup when a type is
+ incomplete but was not also a TagType.
+ (`#57387 <https://github.com/llvm/llvm-project/issues/57387>`_)
-OpenCL C Language Changes in Clang
-----------------------------------
+- Fix a crash when attempting to default a virtual constexpr non-special member
+ function in a derived class.
+ (`#57431 <https://github.com/llvm/llvm-project/issues/57431>`_)
-...
+- Fix ``-Wpre-c++17-compat`` crashing Clang when compiling C++20 code which
+ contains deduced template specializations.
+ (`#57369 <https://github.com/llvm/llvm-project/issues/57369>`_,
+ `#57643 <https://github.com/llvm/llvm-project/issues/57643>`_,
+ `#57793 <https://github.com/llvm/llvm-project/issues/57793>`_)
-ABI Changes in Clang
---------------------
+- Fix a crash upon stray coloncolon token in C2x mode.
-- 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, PS4 and AIX).
- You can switch back to the old ABI behavior with the flag:
- ``-fclang-abi-compat=15.0``.
-- GCC allows POD types to have defaulted special members. Clang historically
- classified such types as non-POD (for the purposes of Itanium ABI). Clang now
- matches the gcc behavior (except on Darwin, PS4, AIX and z/OS). You can switch
- back to the old ABI behavior with the flag: ``-fclang-abi-compat=15.0``.
+- Fix assert that triggers a crash during some types of list initialization that
+ generate a CXXTemporaryObjectExpr instead of a InitListExpr.
+ (`#58302 <https://github.com/llvm/llvm-project/issues/58302>`_,
+ `#58753 <https://github.com/llvm/llvm-project/issues/58753>`_,
+ `#59100 <https://github.com/llvm/llvm-project/issues/59100>`_)
-OpenMP Support in Clang
------------------------
+- Fix a crash where we attempt to define a deleted destructor.
+ (`#57516 <https://github.com/llvm/llvm-project/issues/57516>`_)
-...
+- Fix an issue that triggers a crash if we instantiate a hidden friend functions.
+ (`#54457 <https://github.com/llvm/llvm-project/issues/54457>`_)
-CUDA Support in Clang
----------------------
+- Fix an issue that makes Clang crash on lambda template parameters.
+ (`#57960 <https://github.com/llvm/llvm-project/issues/57960>`_)
-- Clang now supports CUDA SDK up to 11.8
-- Added support for targeting sm_{87,89,90} GPUs.
+- Fixed a crash in C++20 mode in Clang and Clangd when compile source
+ with compilation errors.
+ (`#53628 <https://github.com/llvm/llvm-project/issues/53628>`_)
+
+- Fix sanity check when value initializing an empty union so that it takes into
+ account anonymous structs which is a GNU extension.
+ (`#58800 <https://github.com/llvm/llvm-project/issues/58800>`_)
-LoongArch Support in Clang
---------------------------
-- Clang now supports LoongArch. Along with the backend, clang is able to build a
- large corpus of Linux applications. Test-suite 100% pass.
-- Support basic option ``-march=`` which is used to select the target
- architecture, i.e. the basic set of ISA modules to be enabled. Possible values
- are ``loongarch64`` and ``la464``.
-- Support basic option ``-mabi=`` which is used to select the base ABI type.
- Possible values are ``lp64d``, ``lp64f``, ``lp64s``, ``ilp32d``, ``ilp32f``
- and ``ilp32s``.
-- Support extended options: ``-msoft-float``, ``-msingle-float``, ``-mdouble-float`` and ``mfpu=``.
- See `LoongArch toolchain conventions <https://loongson.github.io/LoongArch-Documentation/LoongArch-toolchain-conventions-EN.html>`_.
-RISC-V Support in Clang
+Target Specific Changes
-----------------------
-- ``sifive-7-rv32`` and ``sifive-7-rv64`` are no longer supported for ``-mcpu``.
- Use ``sifive-e76``, ``sifive-s76``, or ``sifive-u74`` instead.
-- Native detections via ``-mcpu=native`` and ``-mtune=native`` are supported.
-- Fix interaction of ``-mcpu`` and ``-march``, RISC-V backend will take the
- architecture extension union of ``-mcpu`` and ``-march`` before, and now will
- take architecture extensions from ``-march`` if both are given.
-- An ABI mismatch between GCC and Clang that related to the
- sign/zero-extension of integer scalars was fixed.
-- An overall simplification of the RISC-V Vector intrinsics are done. The
- simplification is based on
- `riscv-non-isa/rvv-intrinsic-doc#186 <https://github.com/riscv-non-isa/rvv-intrinsic-doc/pull/186>`_.
-- Intrinsics of `vcompress` and `vmerge` have been adjusted to have interfaces
- be aligned among `vvm`, `vxm` intrinsics. The adjustment is base on
- `riscv-non-isa/rvv-intrinsic-doc#185 <https://github.com/riscv-non-isa/rvv-intrinsic-doc/pull/185>`_.
-- All RISC-V Vector intrinsics now share a `__riscv_` prefix, based on the
- naming convention defined by
- `riscv-non-isa/riscv-c-api-doc#31 <https://github.com/riscv-non-isa/riscv-c-api-doc/pull/31>`_.
-- Note that the RISC-V Vector C intrinsics are still under development. The RVV
- C Intrinsic Task Group is working towards a ratified v1.0.
-- The rvv-intrinsic-doc provides `compatible headers <https://github.com/riscv-non-isa/rvv-intrinsic-doc/tree/master/auto-generated/rvv-v0p10-compatible-headers>`_ for transition from the previous implemented version to the current (v0.11) version.
-X86 Support in Clang
---------------------
+X86 Support
+^^^^^^^^^^^
- Support ``-mindirect-branch-cs-prefix`` for call and jmp to indirect thunk.
- Fix 32-bit ``__fastcall`` and ``__vectorcall`` ABI mismatch with MSVC.
- Add ISA of ``AMX-FP16`` which support ``_tile_dpfp16ps``.
@@ -930,27 +972,9 @@ X86 Support in Clang
- Support intrinsics of ``_mm(256)_reduce_(add|mul|or|and)_epi8/16``.
- Support intrinsics of ``_mm(256)_reduce_(max|min)_ep[i|u]8/16``.
-WebAssembly Support in Clang
-----------------------------
-
-The -mcpu=generic configuration now enables sign-ext and mutable-globals. These
-proposals are standardized and available in all major engines.
-
-DWARF Support in Clang
-----------------------
-
-Previously when emitting DWARFv4 and tuning for GDB, Clang would use DWARF v2's
-``DW_AT_bit_offset`` and ``DW_AT_data_member_location``. Clang now uses DWARF v4's
-``DW_AT_data_bit_offset`` regardless of tuning.
-
-Support for ``DW_AT_data_bit_offset`` was added in GDB 8.0. For earlier versions,
-you can use the ``-gdwarf-3`` option to emit compatible DWARF.
-
-Arm and AArch64 Support in Clang
---------------------------------
-
+Arm and AArch64 Support
+^^^^^^^^^^^^^^^^^^^^^^^
- 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``.
@@ -960,7 +984,6 @@ Arm and AArch64 Support in Clang
Their presence gave the impression that Clang can correctly generate code for
them, which it cannot.
- Support has been added for the following processors (-mcpu identifiers in parenthesis):
-
* Arm Cortex-A715 (cortex-a715).
* Arm Cortex-X3 (cortex-x3).
* Arm Neoverse V2 (neoverse-v2)
@@ -968,6 +991,88 @@ Arm and AArch64 Support in Clang
``-ftrapping-math``, ``-frounding-math``, ``-ffp-model=strict``, and
``-ffp-exception-behaviour=<arg>`` are now accepted.
+Windows Support
+^^^^^^^^^^^^^^^
+- For the MinGW driver, added the options ``-mguard=none``, ``-mguard=cf`` and
+ ``-mguard=cf-nochecks`` (equivalent to ``/guard:cf-``, ``/guard:cf`` and
+ ``/guard:cf,nochecks`` in clang-cl) for enabling Control Flow Guard checks
+ and generation of address-taken function table.
+- Switched from SHA1 to BLAKE3 for PDB type hashing / ``-gcodeview-ghash``
+- Fixed code generation with emulated TLS, when the emulated TLS is enabled
+ by default (with downstream patches; no upstream configurations default
+ to this configuration, but some mingw downstreams change the default
+ in this way).
+- Improved detection of MinGW cross sysroots for finding sysroots provided
+ by Linux distributions such as Fedora. Also improved such setups by
+ avoiding to include ``/usr/include`` among the include paths when cross
+ compiling with a cross sysroot based in ``/usr``.
+
+LoongArch Support
+^^^^^^^^^^^^^^^^^
+- Clang now supports LoongArch. Along with the backend, clang is able to build a
+ large corpus of Linux applications. Test-suite 100% pass.
+- Support basic option ``-march=`` which is used to select the target
+ architecture, i.e. the basic set of ISA modules to be enabled. Possible values
+ are ``loongarch64`` and ``la464``.
+- Support basic option ``-mabi=`` which is used to select the base ABI type.
+ Possible values are ``lp64d``, ``lp64f``, ``lp64s``, ``ilp32d``, ``ilp32f``
+ and ``ilp32s``.
+- Support extended options: ``-msoft-float``, ``-msingle-float``, ``-mdouble-float`` and ``mfpu=``.
+ See `LoongArch toolchain conventions <https://loongson.github.io/LoongArch-Documentation/LoongArch-toolchain-conventions-EN.html>`_.
+
+RISC-V Support
+^^^^^^^^^^^^^^
+- ``sifive-7-rv32`` and ``sifive-7-rv64`` are no longer supported for ``-mcpu``.
+ Use ``sifive-e76``, ``sifive-s76``, or ``sifive-u74`` instead.
+- Native detections via ``-mcpu=native`` and ``-mtune=native`` are supported.
+- Fix interaction of ``-mcpu`` and ``-march``, RISC-V backend will take the
+ architecture extension union of ``-mcpu`` and ``-march`` before, and now will
+ take architecture extensions from ``-march`` if both are given.
+- An ABI mismatch between GCC and Clang that related to the
+ sign/zero-extension of integer scalars was fixed.
+- An overall simplification of the RISC-V Vector intrinsics are done. The
+ simplification is based on
+ `riscv-non-isa/rvv-intrinsic-doc#186 <https://github.com/riscv-non-isa/rvv-intrinsic-doc/pull/186>`_.
+- Intrinsics of `vcompress` and `vmerge` have been adjusted to have interfaces
+ be aligned among `vvm`, `vxm` intrinsics. The adjustment is base on
+ `riscv-non-isa/rvv-intrinsic-doc#185 <https://github.com/riscv- non-isa/rvv-intrinsic-doc/pull/185>`_.
+- All RISC-V Vector intrinsics now share a `__riscv_` prefix, based on the
+ naming convention defined by
+ `riscv-non-isa/riscv-c-api-doc#31 <https://github.com/riscv-non-isa/riscv-c-api-doc/pull/31>`_.
+- Note that the RISC-V Vector C intrinsics are still under development. The RVV
+ C Intrinsic Task Group is working towards a ratified v1.0.
+- The rvv-intrinsic-doc provides `compatible headers <https://github.com/riscv-non-isa/rvv-intrinsic-doc/tree/master/auto-generated/rvv-v0p10-compatible-headers>`_ for transition from the previous implemented version to the current (v0.11) version.
+
+CUDA/HIP Language Changes in Clang
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Allow the use of ``__noinline__`` as a keyword (instead of ``__attribute__((noinline))``)
+ in lambda declarations.
+
+CUDA Support
+^^^^^^^^^^^^
+- Clang now supports CUDA SDK up to 11.8
+- Added support for targeting sm_{87,89,90} GPUs.
+
+AIX Support
+^^^^^^^^^^^
+* When using ``-shared``, the clang driver now invokes llvm-nm to create an
+ export list if the user doesn't specify one via linker flag or pass an
+ alternative export control option.
+
+WebAssembly Support
+^^^^^^^^^^^^^^^^^^^
+- The -mcpu=generic configuration now enables sign-ext and mutable-globals. These
+ proposals are standardized and available in all major engines.
+
+DWARF Support in Clang
+----------------------
+Previously when emitting DWARFv4 and tuning for GDB, Clang would use DWARF v2's
+``DW_AT_bit_offset`` and ``DW_AT_data_member_location``. Clang now uses DWARF v4's
+``DW_AT_data_bit_offset`` regardless of tuning.
+
+Support for ``DW_AT_data_bit_offset`` was added in GDB 8.0. For earlier versions,
+you can use the ``-gdwarf-3`` option to emit compatible DWARF.
+
Floating Point Support in Clang
-------------------------------
- The driver option ``-menable-unsafe-fp-math`` has been removed. To enable
@@ -975,12 +1080,6 @@ Floating Point Support in Clang
``-ffast-math`` instead.
- Add ``__builtin_elementwise_sin`` and ``__builtin_elementwise_cos`` builtins for floating point types only.
-Internal API Changes
---------------------
-
-Build System Changes
---------------------
-
AST Matchers
------------
- Add ``isInAnoymousNamespace`` matcher to match declarations in an anonymous namespace.
@@ -998,9 +1097,6 @@ clang-format
- Add ``InsertNewlineAtEOF`` option for inserting a newline at EOF if missing.
- Add ``LineEnding`` option to deprecate ``DeriveLineEnding`` and ``UseCRLF``.
-clang-extdef-mapping
---------------------
-
libclang
--------
- Introduced the new function ``clang_getUnqualifiedType``, which mimics
@@ -1047,26 +1143,6 @@ Sanitizers
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
======================
@@ -1078,5 +1154,5 @@ 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)
+contact us on the `Discourse forums (Clang Frontend category)
<https://discourse.llvm.org/c/clang/6>`_.
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