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 75Changes to building LLVM 76------------------------ 77 78* Omitting ``CMAKE_BUILD_TYPE`` when using a single configuration generator is now 79 an error. You now have to pass ``-DCMAKE_BUILD_TYPE=<type>`` in order to configure 80 LLVM. This is done to help new users of LLVM select the correct type: since building 81 LLVM in Debug mode is very resource intensive, we want to make sure that new users 82 make the choice that lines up with their usage. We have also improved documentation 83 around this setting that should help new users. You can find this documentation 84 `here <https://llvm.org/docs/CMake.html#cmake-build-type>`_. 85 86Changes to TableGen 87------------------- 88 89Changes to the AArch64 Backend 90------------------------------ 91 92Changes to the AMDGPU Backend 93----------------------------- 94 95* 8 and 16-bit atomic loads and stores are now supported 96 97 98Changes to the ARM Backend 99-------------------------- 100 101* Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures. 102* Added support for the Armv8.1-M PACBTI-M extension. 103* Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures. 104* Added support for the Armv8.1-M PACBTI-M extension. 105* Removed the deprecation of ARMv8-A T32 Complex IT blocks. No deprecation 106 warnings will be generated and -mrestrict-it is now always off by default. 107 Previously it was on by default for Armv8 and off for all other architecture 108 versions. 109* Added a pass to workaround Cortex-A57 Erratum 1742098 and Cortex-A72 110 Erratum 1655431. This is enabled by default when targeting either CPU. 111* Implemented generation of Windows SEH unwind information. 112* Switched the MinGW target to use SEH instead of DWARF for unwind information. 113 114Changes to the AVR Backend 115-------------------------- 116 117* ... 118 119Changes to the DirectX Backend 120------------------------------ 121 122* DirectX has been added as an experimental target. Specify 123 ``-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=DirectX`` in your CMake configuration 124 to enable it. The target is not packaged in pre-built binaries. 125* The DirectX backend supports the ``dxil`` architecture which is based on LLVM 126 3.6 IR encoded as bitcode and is the format used for DirectX GPU Shader 127 programs. 128 129Changes to the Hexagon Backend 130------------------------------ 131 132* ... 133 134Changes to the MIPS Backend 135--------------------------- 136 137* ... 138 139Changes to the PowerPC Backend 140------------------------------ 141 142* ... 143 144Changes to the RISC-V Backend 145----------------------------- 146 147* The Zvfh extension was added. 148 149Changes to the WebAssembly Backend 150---------------------------------- 151 152* ... 153 154Changes to the X86 Backend 155-------------------------- 156 157* Support ``half`` type on SSE2 and above targets. 158 159Changes to the OCaml bindings 160----------------------------- 161 162 163Changes to the C API 164-------------------- 165 166* Add ``LLVMGetCastOpcode`` function to aid users of ``LLVMBuildCast`` in 167 resolving the best cast operation given a source value and destination type. 168 This function is a direct wrapper of ``CastInst::getCastOpcode``. 169 170* Add ``LLVMGetAggregateElement`` function as a wrapper for 171 ``Constant::getAggregateElement``, which can be used to fetch an element of a 172 constant struct, array or vector, independently of the underlying 173 representation. The ``LLVMGetElementAsConstant`` function is deprecated in 174 favor of the new function, which works on all constant aggregates, rather than 175 only instances of ``ConstantDataSequential``. 176 177* The following functions for creating constant expressions have been removed, 178 because the underlying constant expressions are no longer supported. Instead, 179 an instruction should be created using the ``LLVMBuildXYZ`` APIs, which will 180 constant fold the operands if possible and create an instruction otherwise: 181 * ``LLVMConstExtractValue`` 182 183Changes to the Go bindings 184-------------------------- 185 186 187Changes to the FastISel infrastructure 188-------------------------------------- 189 190* ... 191 192Changes to the DAG infrastructure 193--------------------------------- 194 195 196Changes to the Debug Info 197--------------------------------- 198 199During this release ... 200 201Changes to the LLVM tools 202--------------------------------- 203 204* (Experimental) :manpage:`llvm-symbolizer(1)` now has ``--filter-markup`` to 205 filter :doc:`Symbolizer Markup </SymbolizerMarkupFormat>` into human-readable 206 form. 207 208Changes to LLDB 209--------------------------------- 210 211* The "memory region" command now has a "--all" option to list all 212 memory regions (including unmapped ranges). This is the equivalent 213 of using address 0 then repeating the command until all regions 214 have been listed. 215* Added "--show-tags" option to the "memory find" command. This is off by default. 216 When enabled, if the target value is found in tagged memory, the tags for that 217 memory will be shown inline with the memory contents. 218* Various memory related parts of LLDB have been updated to handle 219 non-address bits (such as AArch64 pointer signatures): 220 221 * "memory read", "memory write" and "memory find" can now be used with 222 addresses with non-address bits. 223 * All the read and write memory methods on SBProccess and SBTarget can 224 be used with addreses with non-address bits. 225 * When printing a pointer expression, LLDB can now dereference the result 226 even if it has non-address bits. 227 * The memory cache now ignores non-address bits when looking up memory 228 locations. This prevents us reading locations multiple times, or not 229 writing out new values if the addresses have different non-address bits. 230 231Changes to Sanitizers 232--------------------- 233 234 235Other Changes 236------------- 237* The code for the `LLVM Visual Studio integration 238 <https://marketplace.visualstudio.com/items?itemName=LLVMExtensions.llvm-toolchain>`_ 239 has been removed. This had been obsolete and abandoned since Visual Studio 240 started including an integration by default in 2019. 241 242External Open Source Projects Using LLVM 15 243=========================================== 244 245* A project... 246 247Additional Information 248====================== 249 250A wide variety of additional information is available on the `LLVM web page 251<https://llvm.org/>`_, in particular in the `documentation 252<https://llvm.org/docs/>`_ section. The web page also contains versions of the 253API documentation which is up-to-date with the Git version of the source 254code. You can access versions of these documents specific to this release by 255going into the ``llvm/docs/`` directory in the LLVM tree. 256 257If you have any questions or comments about LLVM, please feel free to contact 258us via the `mailing lists <https://llvm.org/docs/#mailing-lists>`_. 259