| ============================ |
| LLVM |release| Release Notes |
| ============================ |
| |
| .. contents:: |
| :local: |
| |
| .. 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>`_. |
| |
| |
| Introduction |
| ============ |
| |
| 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 <https://llvm.org/releases/>`_. |
| |
| For more information about LLVM, including information about the latest |
| release, please check out the `main LLVM web site <https://llvm.org/>`_. If you |
| have questions or comments, the `Discourse forums |
| <https://discourse.llvm.org>`_ is a good place to ask |
| 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 <https://llvm.org/releases/>`_. |
| |
| Non-comprehensive list of changes in this release |
| ================================================= |
| .. NOTE |
| For small 1-3 sentence descriptions, just add an entry at the end of |
| this list. If your description won't fit comfortably in one bullet |
| point (e.g. maybe you would like to give an example of the |
| functionality, or simply have a lot to talk about), see the `NOTE` below |
| for adding a new subsection. |
| |
| * The ``readnone`` calls which are crossing suspend points in coroutines will |
| not be merged. Since ``readnone`` calls may access thread id and thread id |
| is not a constant in coroutines. This decision may cause unnecessary |
| performance regressions and we plan to fix it in later versions. |
| |
| * ... |
| |
| Update on required toolchains to build LLVM |
| ------------------------------------------- |
| |
| LLVM is now built with C++17 by default. This means C++17 can be used in |
| the code base. |
| |
| The previous "soft" toolchain requirements have now been changed to "hard". |
| This means that the the following versions are now required to build LLVM |
| and there is no way to suppress this error. |
| |
| * GCC >= 7.1 |
| * Clang >= 5.0 |
| * Apple Clang >= 10.0 |
| * Visual Studio 2019 >= 16.7 |
| |
| Changes to the LLVM IR |
| ---------------------- |
| |
| * The ``readnone``, ``readonly``, ``writeonly``, ``argmemonly``, |
| ``inaccessiblememonly`` and ``inaccessiblemem_or_argmemonly`` function |
| attributes have been replaced by a single ``memory(...)`` attribute. The |
| old attributes may be mapped to the new one as follows: |
| |
| * ``readnone`` -> ``memory(none)`` |
| * ``readonly`` -> ``memory(read)`` |
| * ``writeonly`` -> ``memory(write)`` |
| * ``argmemonly`` -> ``memory(argmem: readwrite)`` |
| * ``argmemonly readonly`` -> ``memory(argmem: read)`` |
| * ``argmemonly writeonly`` -> ``memory(argmem: write)`` |
| * ``inaccessiblememonly`` -> ``memory(inaccessiblemem: readwrite)`` |
| * ``inaccessiblememonly readonly`` -> ``memory(inaccessiblemem: read)`` |
| * ``inaccessiblememonly writeonly`` -> ``memory(inaccessiblemem: write)`` |
| * ``inaccessiblemem_or_argmemonly`` -> |
| ``memory(argmem: readwrite, inaccessiblemem: readwrite)`` |
| * ``inaccessiblemem_or_argmemonly readonly`` -> |
| ``memory(argmem: read, inaccessiblemem: read)`` |
| * ``inaccessiblemem_or_argmemonly writeonly`` -> |
| ``memory(argmem: write, inaccessiblemem: write)`` |
| |
| * The constant expression variants of the following instructions has been |
| removed: |
| |
| * ``fneg`` |
| |
| Changes to building LLVM |
| ------------------------ |
| |
| Changes to TableGen |
| ------------------- |
| |
| Changes to the AArch64 Backend |
| ------------------------------ |
| |
| * Added support for the Cortex-A715 CPU. |
| * Added support for the Cortex-X3 CPU. |
| * Added support for assembly for RME MEC (Memory Encryption Contexts). |
| |
| Changes to the AMDGPU Backend |
| ----------------------------- |
| |
| Changes to the ARM Backend |
| -------------------------- |
| |
| * Support for targeting armv2, armv2A, armv3 and armv3M has been removed. |
| LLVM did not, and was not ever likely to generate correct code for those |
| architecture versions so their presence was misleading. |
| |
| 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 |
| ----------------------------- |
| |
| * Support for the unratified Zbe, Zbf, Zbm, Zbp, Zbr, and Zbt extensions have |
| been removed. |
| * i32 is now a native type in the datalayout string. This enables |
| LoopStrengthReduce for loops with i32 induction variables, among other |
| optimizations. |
| |
| Changes to the WebAssembly Backend |
| ---------------------------------- |
| |
| * ... |
| |
| Changes to the Windows Target |
| ----------------------------- |
| |
| * For MinGW, generate embedded ``-exclude-symbols:`` directives for symbols |
| with hidden visibility, omitting them from automatic export of all symbols. |
| This roughly makes hidden visibility work like it does for other object |
| file formats. |
| |
| Changes to the X86 Backend |
| -------------------------- |
| |
| * Add support for the ``RDMSRLIST and WRMSRLIST`` instructions. |
| * Add support for the ``WRMSRNS`` instruction. |
| * Support ISA of ``AMX-FP16`` which contains ``tdpfp16ps`` instruction. |
| * Support ISA of ``CMPCCXADD``. |
| * Support ISA of ``AVX-IFMA``. |
| * Support ISA of ``AVX-VNNI-INT8``. |
| * Support ISA of ``AVX-NE-CONVERT``. |
| * ``-mcpu=raptorlake`` and ``-mcpu=meteorlake`` are now supported. |
| * ``-mcpu=sierraforest``, ``-mcpu=graniterapids`` and ``-mcpu=grandridge`` are now supported. |
| |
| Changes to the OCaml bindings |
| ----------------------------- |
| |
| |
| Changes to the C API |
| -------------------- |
| |
| * 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: |
| |
| * ``LLVMConstFNeg`` |
| |
| Changes to the Go bindings |
| -------------------------- |
| |
| |
| Changes to the FastISel infrastructure |
| -------------------------------------- |
| |
| * ... |
| |
| Changes to the DAG infrastructure |
| --------------------------------- |
| |
| |
| Changes to the Metadata Info |
| --------------------------------- |
| |
| * Add Module Flags Metadata ``stack-protector-guard-symbol`` which specify a |
| symbol for addressing the stack-protector guard. |
| |
| Changes to the Debug Info |
| --------------------------------- |
| |
| Previously when emitting DWARF v4 and tuning for GDB, llc would use DWARF v2's |
| ``DW_AT_bit_offset`` and ``DW_AT_data_member_location``. llc 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 llc's ``-dwarf-version=3`` option to emit compatible DWARF. |
| |
| Changes to the LLVM tools |
| --------------------------------- |
| |
| * ``llvm-readobj --elf-output-style=JSON`` no longer prefixes each JSON object |
| with the file name. Previously, each object file's output looked like |
| ``"main.o":{"FileSummary":{"File":"main.o"},...}`` but is now |
| ``{"FileSummary":{"File":"main.o"},...}``. This allows each JSON object to be |
| parsed in the same way, since each object no longer has a unique key. Tools |
| that consume ``llvm-readobj``'s JSON output should update their parsers |
| accordingly. |
| |
| * ``llvm-objdump`` now uses ``--print-imm-hex`` by default, which brings its |
| default behavior closer in line with ``objdump``. |
| |
| Changes to LLDB |
| --------------------------------- |
| |
| Changes to Sanitizers |
| --------------------- |
| |
| |
| Other Changes |
| ------------- |
| |
| External Open Source Projects Using LLVM 15 |
| =========================================== |
| |
| * A project... |
| |
| Additional Information |
| ====================== |
| |
| A wide variety of additional information is available on the `LLVM web page |
| <https://llvm.org/>`_, in particular in the `documentation |
| <https://llvm.org/docs/>`_ 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 `Discourse forums <https://discourse.llvm.org>`_. |
