1============================ 2LLVM |release| Release Notes 3============================ 4 5.. contents:: 6 :local: 7 8.. only:: PreRelease 9 10 .. warning:: 11 These are in-progress notes for the upcoming LLVM |version| release. 12 Release notes for previous releases can be found on 13 `the Download Page <https://releases.llvm.org/download.html>`_. 14 15 16Introduction 17============ 18 19This document contains the release notes for the LLVM Compiler Infrastructure, 20release |release|. Here we describe the status of LLVM, including major improvements 21from the previous release, improvements in various subprojects of LLVM, and 22some of the current users of the code. All LLVM releases may be downloaded 23from the `LLVM releases web site <https://llvm.org/releases/>`_. 24 25For more information about LLVM, including information about the latest 26release, please check out the `main LLVM web site <https://llvm.org/>`_. If you 27have questions or comments, the `LLVM Developer's Mailing List 28<https://lists.llvm.org/mailman/listinfo/llvm-dev>`_ is a good place to send 29them. 30 31Note that if you are reading this file from a Git checkout or the main 32LLVM web page, this document applies to the *next* release, not the current 33one. To see the release notes for a specific release, please see the `releases 34page <https://llvm.org/releases/>`_. 35 36Non-comprehensive list of changes in this release 37================================================= 38.. NOTE 39 For small 1-3 sentence descriptions, just add an entry at the end of 40 this list. If your description won't fit comfortably in one bullet 41 point (e.g. maybe you would like to give an example of the 42 functionality, or simply have a lot to talk about), see the `NOTE` below 43 for adding a new subsection. 44 45* ... 46 47Update on required toolchains to build LLVM 48------------------------------------------- 49 50With LLVM 15.x we will raise the version requirements of the toolchain used 51to build LLVM. The new requirements are as follows: 52 53* GCC >= 7.1 54* Clang >= 5.0 55* Apple Clang >= 9.3 56* Visual Studio 2019 >= 16.7 57 58In LLVM 15.x these requirements will be "soft" requirements and the version 59check can be skipped by passing -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON 60to CMake. 61 62With the release of LLVM 16.x these requirements will be hard and LLVM developers 63can start using C++17 features, making it impossible to build with older 64versions of these toolchains. 65 66Changes to the LLVM IR 67---------------------- 68 69* Renamed ``llvm.experimental.vector.extract`` intrinsic to ``llvm.vector.extract``. 70* Renamed ``llvm.experimental.vector.insert`` intrinsic to ``llvm.vector.insert``. 71* The constant expression variants of the following instructions have been 72 removed: 73 * ``extractvalue`` 74 * ``insertvalue`` 75 76Changes to building LLVM 77------------------------ 78 79* Omitting ``CMAKE_BUILD_TYPE`` when using a single configuration generator is now 80 an error. You now have to pass ``-DCMAKE_BUILD_TYPE=<type>`` in order to configure 81 LLVM. This is done to help new users of LLVM select the correct type: since building 82 LLVM in Debug mode is very resource intensive, we want to make sure that new users 83 make the choice that lines up with their usage. We have also improved documentation 84 around this setting that should help new users. You can find this documentation 85 `here <https://llvm.org/docs/CMake.html#cmake-build-type>`_. 86 87Changes to TableGen 88------------------- 89 90Changes to the AArch64 Backend 91------------------------------ 92 93Changes to the AMDGPU Backend 94----------------------------- 95 96* 8 and 16-bit atomic loads and stores are now supported 97 98 99Changes to the ARM Backend 100-------------------------- 101 102* Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures. 103* Added support for the Armv8.1-M PACBTI-M extension. 104* Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures. 105* Added support for the Armv8.1-M PACBTI-M extension. 106* Removed the deprecation of ARMv8-A T32 Complex IT blocks. No deprecation 107 warnings will be generated and -mrestrict-it is now always off by default. 108 Previously it was on by default for Armv8 and off for all other architecture 109 versions. 110* Added a pass to workaround Cortex-A57 Erratum 1742098 and Cortex-A72 111 Erratum 1655431. This is enabled by default when targeting either CPU. 112* Implemented generation of Windows SEH unwind information. 113* Switched the MinGW target to use SEH instead of DWARF for unwind information. 114* Added support for the Cortex-M85 CPU. 115 116Changes to the AVR Backend 117-------------------------- 118 119* ... 120 121Changes to the DirectX Backend 122------------------------------ 123 124* DirectX has been added as an experimental target. Specify 125 ``-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=DirectX`` in your CMake configuration 126 to enable it. The target is not packaged in pre-built binaries. 127* The DirectX backend supports the ``dxil`` architecture which is based on LLVM 128 3.6 IR encoded as bitcode and is the format used for DirectX GPU Shader 129 programs. 130 131Changes to the Hexagon Backend 132------------------------------ 133 134* ... 135 136Changes to the MIPS Backend 137--------------------------- 138 139* ... 140 141Changes to the PowerPC Backend 142------------------------------ 143 144* ... 145 146Changes to the RISC-V Backend 147----------------------------- 148 149* The Zvfh extension was added. 150 151Changes to the WebAssembly Backend 152---------------------------------- 153 154* ... 155 156Changes to the X86 Backend 157-------------------------- 158 159* Support ``half`` type on SSE2 and above targets. 160 161Changes to the OCaml bindings 162----------------------------- 163 164 165Changes to the C API 166-------------------- 167 168* Add ``LLVMGetCastOpcode`` function to aid users of ``LLVMBuildCast`` in 169 resolving the best cast operation given a source value and destination type. 170 This function is a direct wrapper of ``CastInst::getCastOpcode``. 171 172* Add ``LLVMGetAggregateElement`` function as a wrapper for 173 ``Constant::getAggregateElement``, which can be used to fetch an element of a 174 constant struct, array or vector, independently of the underlying 175 representation. The ``LLVMGetElementAsConstant`` function is deprecated in 176 favor of the new function, which works on all constant aggregates, rather than 177 only instances of ``ConstantDataSequential``. 178 179* The following functions for creating constant expressions have been removed, 180 because the underlying constant expressions are no longer supported. Instead, 181 an instruction should be created using the ``LLVMBuildXYZ`` APIs, which will 182 constant fold the operands if possible and create an instruction otherwise: 183 * ``LLVMConstExtractValue`` 184 * ``LLVMConstInsertValue`` 185 186Changes to the Go bindings 187-------------------------- 188 189 190Changes to the FastISel infrastructure 191-------------------------------------- 192 193* ... 194 195Changes to the DAG infrastructure 196--------------------------------- 197 198 199Changes to the Debug Info 200--------------------------------- 201 202During this release ... 203 204Changes to the LLVM tools 205--------------------------------- 206 207* (Experimental) :manpage:`llvm-symbolizer(1)` now has ``--filter-markup`` to 208 filter :doc:`Symbolizer Markup </SymbolizerMarkupFormat>` into human-readable 209 form. 210* :doc:`llvm-objcopy <CommandGuide/llvm-objcopy>` has removed support for the legacy ``zlib-gnu`` format. 211 212Changes to LLDB 213--------------------------------- 214 215* The "memory region" command now has a "--all" option to list all 216 memory regions (including unmapped ranges). This is the equivalent 217 of using address 0 then repeating the command until all regions 218 have been listed. 219* Added "--show-tags" option to the "memory find" command. This is off by default. 220 When enabled, if the target value is found in tagged memory, the tags for that 221 memory will be shown inline with the memory contents. 222* Various memory related parts of LLDB have been updated to handle 223 non-address bits (such as AArch64 pointer signatures): 224 225 * "memory read", "memory write" and "memory find" can now be used with 226 addresses with non-address bits. 227 * All the read and write memory methods on SBProccess and SBTarget can 228 be used with addreses with non-address bits. 229 * When printing a pointer expression, LLDB can now dereference the result 230 even if it has non-address bits. 231 * The memory cache now ignores non-address bits when looking up memory 232 locations. This prevents us reading locations multiple times, or not 233 writing out new values if the addresses have different non-address bits. 234 235Changes to Sanitizers 236--------------------- 237 238 239Other Changes 240------------- 241* The code for the `LLVM Visual Studio integration 242 <https://marketplace.visualstudio.com/items?itemName=LLVMExtensions.llvm-toolchain>`_ 243 has been removed. This had been obsolete and abandoned since Visual Studio 244 started including an integration by default in 2019. 245 246External Open Source Projects Using LLVM 15 247=========================================== 248 249* A project... 250 251Additional Information 252====================== 253 254A wide variety of additional information is available on the `LLVM web page 255<https://llvm.org/>`_, in particular in the `documentation 256<https://llvm.org/docs/>`_ section. The web page also contains versions of the 257API documentation which is up-to-date with the Git version of the source 258code. You can access versions of these documents specific to this release by 259going into the ``llvm/docs/`` directory in the LLVM tree. 260 261If you have any questions or comments about LLVM, please feel free to contact 262us via the `mailing lists <https://llvm.org/docs/#mailing-lists>`_. 263