LLVM |release| Release Notes
- Introduction
- Non-comprehensive list of changes in this release
- Update on required toolchains to build LLVM
- Changes to the LLVM IR
- Changes to building LLVM
- Changes to TableGen
- Changes to the AArch64 Backend
- Changes to the AMDGPU Backend
- Changes to the ARM Backend
- Changes to the AVR Backend
- Changes to the DirectX Backend
- Changes to the Hexagon Backend
- Changes to the MIPS Backend
- Changes to the PowerPC Backend
- Changes to the RISC-V Backend
- Changes to the WebAssembly Backend
- Changes to the X86 Backend
- Changes to the OCaml bindings
- Changes to the C API
- Changes to the Go bindings
- Changes to the FastISel infrastructure
- Changes to the DAG infrastructure
- Changes to the Metadata Info
- Changes to the Debug Info
- Changes to the LLVM tools
- Changes to LLDB
- Changes to Sanitizers
- Other Changes
- External Open Source Projects Using LLVM 15
- Additional Information
.. only:: PreRelease .. warning:: These are in-progress notes for the upcoming LLVM |version| release. Release notes for previous releases can be found on `the Download Page <https://releases.llvm.org/download.html>`_.
This document contains the release notes for the LLVM Compiler Infrastructure, release |release|. Here we describe the status of LLVM, including major improvements from the previous release, improvements in various subprojects of LLVM, and some of the current users of the code. All LLVM releases may be downloaded from the LLVM releases web site.
For more information about LLVM, including information about the latest release, please check out the main LLVM web site. If you have questions or comments, the LLVM Developer's Mailing List is a good place to send them.
Note that if you are reading this file from a Git checkout or the main LLVM 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.
- ...
With LLVM 15.x we will raise the version requirements of the toolchain used to build LLVM. The new requirements are as follows:
- GCC >= 7.1
- Clang >= 5.0
- Apple Clang >= 9.3
- Visual Studio 2019 >= 16.7
In LLVM 15.x these requirements will be "soft" requirements and the version check can be skipped by passing -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON to CMake.
With the release of LLVM 16.x these requirements will be hard and LLVM developers can start using C++17 features, making it impossible to build with older versions of these toolchains.
- Renamed
llvm.experimental.vector.extract
intrinsic tollvm.vector.extract
. - Renamed
llvm.experimental.vector.insert
intrinsic tollvm.vector.insert
. - The constant expression variants of the following instructions have been
removed:
*
extractvalue
*insertvalue
*udiv
*sdiv
*urem
*srem
*fadd
*fsub
*fmul
*fdiv
*frem
- Added the support for
fmax
andfmin
inatomicrmw
instruction. The comparison is expected to match the behavior ofllvm.maxnum.*
andllvm.minnum.*
respectively.
- Omitting
CMAKE_BUILD_TYPE
when using a single configuration generator is now an error. You now have to pass-DCMAKE_BUILD_TYPE=<type>
in order to configure LLVM. This is done to help new users of LLVM select the correct type: since building LLVM in Debug mode is very resource intensive, we want to make sure that new users make the choice that lines up with their usage. We have also improved documentation around this setting that should help new users. You can find this documentation here.
- 8 and 16-bit atomic loads and stores are now supported
- Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures.
- Added support for the Armv8.1-M PACBTI-M extension.
- Added support for the Armv9-A, Armv9.1-A and Armv9.2-A architectures.
- Added support for the Armv8.1-M PACBTI-M extension.
- Removed the deprecation of ARMv8-A T32 Complex IT blocks. No deprecation warnings will be generated and -mrestrict-it is now always off by default. Previously it was on by default for Armv8 and off for all other architecture versions.
- Added a pass to workaround Cortex-A57 Erratum 1742098 and Cortex-A72 Erratum 1655431. This is enabled by default when targeting either CPU.
- Implemented generation of Windows SEH unwind information.
- Switched the MinGW target to use SEH instead of DWARF for unwind information.
- Added support for the Cortex-M85 CPU.
- Added support for a new -mframe-chain=(none|aapcs|aapcs+leaf) command-line option, which controls the generation of AAPCS-compliant Frame Records.
- ...
- DirectX has been added as an experimental target. Specify
-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=DirectX
in your CMake configuration to enable it. The target is not packaged in pre-built binaries. - The DirectX backend supports the
dxil
architecture which is based on LLVM 3.6 IR encoded as bitcode and is the format used for DirectX GPU Shader programs.
- ...
- ...
- ...
- The Zvfh extension was added.
- ...
- Support
half
type on SSE2 and above targets. - Support
rdpru
instruction on Zen2 and above targets.
- Add
LLVMGetCastOpcode
function to aid users ofLLVMBuildCast
in resolving the best cast operation given a source value and destination type. This function is a direct wrapper ofCastInst::getCastOpcode
. - Add
LLVMGetAggregateElement
function as a wrapper forConstant::getAggregateElement
, which can be used to fetch an element of a constant struct, array or vector, independently of the underlying representation. TheLLVMGetElementAsConstant
function is deprecated in favor of the new function, which works on all constant aggregates, rather than only instances ofConstantDataSequential
. - The following functions for creating constant expressions have been removed,
because the underlying constant expressions are no longer supported. Instead,
an instruction should be created using the
LLVMBuildXYZ
APIs, which will constant fold the operands if possible and create an instruction otherwise: *LLVMConstExtractValue
*LLVMConstInsertValue
*LLVMConstUDiv
*LLVMConstExactUDiv
*LLVMConstSDiv
*LLVMConstExactSDiv
*LLVMConstURem
*LLVMConstSRem
*LLVMConstFAdd
*LLVMConstFSub
*LLVMConstFMul
*LLVMConstFDiv
*LLVMConstFRem
- Add
LLVMDeleteInstruction
function which allows deleting instructions that are not inserted into a basic block. - Refactor compression namespaces across the project, making way for a possible
introduction of alternatives to zlib compression in the llvm toolchain.
Changes are as follows:
* Relocate the
llvm::zlib
namespace tollvm::compression::zlib
. * Remove crc32 from zlib compression namespace, people should use thellvm::crc32
instead.
- ...
- Add Module Flags Metadata
stack-protector-guard-symbol
which specify a symbol for addressing the stack-protector guard.
During this release ...
- (Experimental) :manpage:`llvm-symbolizer(1)` now has
--filter-markup
to filter :doc:`Symbolizer Markup </SymbolizerMarkupFormat>` into human-readable form. - :doc:`llvm-objcopy <CommandGuide/llvm-objcopy>` has removed support for the legacy
zlib-gnu
format. - :doc:`llvm-objcopy <CommandGuide/llvm-objcopy>` now allows
--set-section-flags src=... --rename-section src=tst
.--add-section=.foo1=... --rename-section=.foo1=.foo2
now adds.foo1
instead of.foo2
.
- The "memory region" command now has a "--all" option to list all memory regions (including unmapped ranges). This is the equivalent of using address 0 then repeating the command until all regions have been listed.
- Added "--show-tags" option to the "memory find" command. This is off by default. When enabled, if the target value is found in tagged memory, the tags for that memory will be shown inline with the memory contents.
- Various memory related parts of LLDB have been updated to handle
non-address bits (such as AArch64 pointer signatures):
- "memory read", "memory write" and "memory find" can now be used with addresses with non-address bits.
- All the read and write memory methods on SBProccess and SBTarget can be used with addreses with non-address bits.
- When printing a pointer expression, LLDB can now dereference the result even if it has non-address bits.
- The memory cache now ignores non-address bits when looking up memory locations. This prevents us reading locations multiple times, or not writing out new values if the addresses have different non-address bits.
- The code for the LLVM Visual Studio integration has been removed. This had been obsolete and abandoned since Visual Studio started including an integration by default in 2019.
- A project...
A wide variety of additional information is available on the LLVM web page, in particular in the documentation section. The web page also contains versions of the
API documentation which is up-to-date with the Git version of the source
code. You can access versions of these documents specific to this release by
going into the llvm/docs/
directory in the LLVM tree.
If you have any questions or comments about LLVM, please feel free to contact us via the mailing lists.