| <!-- This document is written in Markdown and uses extra directives provided by |
| MyST (https://myst-parser.readthedocs.io/en/latest/). --> |
| |
| LLVM {{env.config.release}} Release Notes |
| ========================================= |
| |
| ```{contents} |
| ``` |
| |
| ````{only} PreRelease |
| ```{warning} These are in-progress notes for the upcoming LLVM {{env.config.release}} |
| 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 {{env.config.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 |
| ================================================= |
| |
| <!-- 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 comment below |
| for adding a new subsection. --> |
| |
| * Added a new IRNormalizer pass which aims to transform LLVM modules into |
| a normal form by reordering and renaming instructions while preserving the |
| same semantics. The normalizer makes it easier to spot semantic differences |
| when diffing two modules which have undergone different passes. |
| |
| * ... |
| |
| <!-- If you would like to document a larger change, then you can add a |
| subsection about it right here. You can copy the following boilerplate: |
| |
| Special New Feature |
| ------------------- |
| |
| Makes programs 10x faster by doing Special New Thing. |
| --> |
| |
| Changes to the LLVM IR |
| ---------------------- |
| |
| * Types are no longer allowed to be recursive. |
| |
| * The `x86_mmx` IR type has been removed. It will be translated to |
| the standard vector type `<1 x i64>` in bitcode upgrade. |
| * Renamed `llvm.experimental.stepvector` intrinsic to `llvm.stepvector`. |
| |
| * Added `usub_cond` and `usub_sat` operations to `atomicrmw`. |
| |
| * Introduced `noalias.addrspace` metadata. |
| |
| * Remove the following intrinsics which can be replaced with a `bitcast`: |
| |
| * `llvm.nvvm.bitcast.f2i` |
| * `llvm.nvvm.bitcast.i2f` |
| * `llvm.nvvm.bitcast.d2ll` |
| * `llvm.nvvm.bitcast.ll2d` |
| |
| * Remove the following intrinsics which can be replaced with a funnel-shift: |
| |
| * `llvm.nvvm.rotate.b32` |
| * `llvm.nvvm.rotate.right.b64` |
| * `llvm.nvvm.rotate.b64` |
| |
| * Remove the following intrinsics which can be replaced with an |
| `addrspacecast`: |
| |
| * `llvm.nvvm.ptr.gen.to.global` |
| * `llvm.nvvm.ptr.gen.to.shared` |
| * `llvm.nvvm.ptr.gen.to.constant` |
| * `llvm.nvvm.ptr.gen.to.local` |
| * `llvm.nvvm.ptr.global.to.gen` |
| * `llvm.nvvm.ptr.shared.to.gen` |
| * `llvm.nvvm.ptr.constant.to.gen` |
| * `llvm.nvvm.ptr.local.to.gen` |
| |
| * Remove the following intrinsics which can be relaced with a load from |
| addrspace(1) with an !invariant.load metadata |
| |
| * `llvm.nvvm.ldg.global.i` |
| * `llvm.nvvm.ldg.global.f` |
| * `llvm.nvvm.ldg.global.p` |
| |
| * Operand bundle values can now be metadata strings. |
| |
| * Fast math flags are now permitted on `fptrunc` and `fpext`. |
| |
| Changes to LLVM infrastructure |
| ------------------------------ |
| |
| Changes to building LLVM |
| ------------------------ |
| |
| * Raised the minimum MSVC version to Visual Studio 2019 16.8. |
| |
| Changes to TableGen |
| ------------------- |
| |
| Changes to Interprocedural Optimizations |
| ---------------------------------------- |
| |
| Changes to the AArch64 Backend |
| ------------------------------ |
| |
| * `.balign N, 0`, `.p2align N, 0`, `.align N, 0` in code sections will now fill |
| the required alignment space with a sequence of `0x0` bytes (the requested |
| fill value) rather than NOPs. |
| |
| * Assembler/disassembler support has been added for Armv9.6-A (2024) |
| architecture extensions. |
| |
| * Added support for the FUJITSU-MONAKA CPU. |
| |
| Changes to the AMDGPU Backend |
| ----------------------------- |
| |
| * Removed `llvm.amdgcn.flat.atomic.fadd` and |
| `llvm.amdgcn.global.atomic.fadd` intrinsics. Users should use the |
| {ref}`atomicrmw <i_atomicrmw>` instruction with `fadd` and |
| addrspace(0) or addrspace(1) instead. |
| |
| Changes to the ARM Backend |
| -------------------------- |
| |
| * `.balign N, 0`, `.p2align N, 0`, `.align N, 0` in code sections will now fill |
| the required alignment space with a sequence of `0x0` bytes (the requested |
| fill value) rather than NOPs. |
| |
| * The default behavior for frame pointers in leaf functions has been updated. |
| When the `-fno-omit-frame-pointer` option is specified, `FPKeepKindStr` is |
| set to `-mframe-pointer=all`, meaning the frame pointer (FP) is now retained |
| in leaf functions by default. To eliminate the frame pointer in leaf functions, |
| you must explicitly use the `-momit-leaf-frame-pointer` option. |
| |
| * When using the `MOVT` or `MOVW` instructions, the Assembler will now check to |
| ensure that any addend that is used is within a 16-bit signed value range. If the |
| addend falls outside of this range, the LLVM backend will emit an error like so |
| `Relocation Not In Range`. |
| |
| Changes to the AVR Backend |
| -------------------------- |
| |
| Changes to the DirectX Backend |
| ------------------------------ |
| |
| Changes to the Hexagon Backend |
| ------------------------------ |
| |
| Changes to the LoongArch Backend |
| -------------------------------- |
| |
| Changes to the MIPS Backend |
| --------------------------- |
| |
| Changes to the PowerPC Backend |
| ------------------------------ |
| |
| * The Linux `ppc64` LLC default cpu is updated from `ppc` to `ppc64`. |
| * The AIX LLC default cpu is updated from `generic` to `pwr7`. |
| |
| Changes to the RISC-V Backend |
| ----------------------------- |
| |
| * `.balign N, 0`, `.p2align N, 0`, `.align N, 0` in code sections will now fill |
| the required alignment space with a sequence of `0x0` bytes (the requested |
| fill value) rather than NOPs. |
| * Added Syntacore SCR4 and SCR5 CPUs: `-mcpu=syntacore-scr4/5-rv32/64` |
| * `-mcpu=sifive-p470` was added. |
| * Added Hazard3 CPU as taped out for RP2350: `-mcpu=rp2350-hazard3` (32-bit |
| only). |
| * Fixed length vector support using RVV instructions now requires VLEN>=64. This |
| means Zve32x and Zve32f will also require Zvl64b. The prior support was |
| largely untested. |
| * The `Zvbc32e` and `Zvkgs` extensions are now supported experimentally. |
| * Added `Smctr`, `Ssctr` and `Svvptc` extensions. |
| * `-mcpu=syntacore-scr7` was added. |
| * `-mcpu=tt-ascalon-d8` was added. |
| * `-mcpu=mips-p8700` was added. |
| * The `Zacas` extension is no longer marked as experimental. |
| * Added Smdbltrp, Ssdbltrp extensions to -march. |
| * The `Smmpm`, `Smnpm`, `Ssnpm`, `Supm`, and `Sspm` pointer masking extensions |
| are no longer marked as experimental. |
| * The `Sha` extension is now supported. |
| * The RVA23U64, RVA23S64, RVB23U64, and RVB23S64 profiles are no longer marked |
| as experimental. |
| * `.insn <length>, <raw encoding>` can be used to assemble 48- and 64-bit |
| instructions from raw integer values. |
| * `.insn [<length>,] <raw encoding>` now accepts absolute expressions for both |
| expressions, so that they can be computed from constants and absolute symbols. |
| * The following new inline assembly constraints and modifiers are accepted: |
| * `cr` constraint meaning an RVC-encoding compatible GPR (`x8`-`x15`) |
| * `cf` constraint meaning an RVC-encoding compatible FPR (`f8`-`f15`) |
| * `R` constraint meaning an even-odd GPR pair (prints as the even register, |
| but both registers in the pair are considered live). |
| * `N` modifer meaning print the register encoding (0-31) rather than the name. |
| * `f` and `cf` inline assembly constraints, when using F-/D-/H-in-X extensions, |
| will use the relevant GPR rather than FPR. This makes inline assembly portable |
| between e.g. F and Zfinx code. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcicsr` (CSR) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcisls` (Scaled Load Store) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcia` (Arithmetic) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqciac` (Load-Store Address Calculation) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcics` (Conditonal Select) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcilsm` (Load Store Multiple) |
| extension. |
| * Adds experimental assembler support for the Qualcomm uC 'Xqcicli` (Conditional Load Immediate) |
| extension. |
| * Added ``Sdext`` and ``Sdtrig`` extensions. |
| |
| Changes to the WebAssembly Backend |
| ---------------------------------- |
| |
| The default target CPU, "generic", now enables the `-mnontrapping-fptoint` |
| and `-mbulk-memory` flags, which correspond to the [Bulk Memory Operations] |
| and [Non-trapping float-to-int Conversions] language features, which are |
| [widely implemented in engines]. |
| |
| A new Lime1 target CPU is added, -mcpu=lime1. This CPU follows the definition of |
| the Lime1 CPU [here], and enables -mmultivalue, -mmutable-globals, |
| -mcall-indirect-overlong, -msign-ext, -mbulk-memory-opt, -mnontrapping-fptoint, |
| and -mextended-const. |
| |
| [Bulk Memory Operations]: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md |
| [Non-trapping float-to-int Conversions]: https://github.com/WebAssembly/spec/blob/master/proposals/nontrapping-float-to-int-conversion/Overview.md |
| [widely implemented in engines]: https://webassembly.org/features/ |
| [here]: https://github.com/WebAssembly/tool-conventions/blob/main/Lime.md#lime1 |
| |
| Changes to the Windows Target |
| ----------------------------- |
| |
| Changes to the X86 Backend |
| -------------------------- |
| |
| * `.balign N, 0x90`, `.p2align N, 0x90`, and `.align N, 0x90` in code sections |
| now fill the required alignment space with repeating `0x90` bytes, rather than |
| using optimised NOP filling. Optimised NOP filling fills the space with NOP |
| instructions of various widths, not just those that use the `0x90` byte |
| encoding. To use optimised NOP filling in a code section, leave off the |
| "fillval" argument, i.e. `.balign N`, `.p2align N` or `.align N` respectively. |
| |
| * Due to the removal of the `x86_mmx` IR type, functions with |
| `x86_mmx` arguments or return values will use a different, |
| incompatible, calling convention ABI. Such functions are not |
| generally seen in the wild (Clang never generates them!), so this is |
| not expected to result in real-world compatibility problems. |
| |
| * Support ISA of `AVX10.2-256` and `AVX10.2-512`. |
| |
| * Supported instructions of `MOVRS AND AVX10.2` |
| |
| * Supported ISA of `SM4(EVEX)`. |
| |
| * Supported ISA of `MSR_IMM`. |
| |
| * Supported ``-mcpu=diamondrapids`` |
| |
| * Supported emitting relocation types for x86-64 target: |
| * `R_X86_64_CODE_4_GOTPCRELX` |
| * `R_X86_64_CODE_4_GOTTPOFF` |
| * `R_X86_64_CODE_4_GOTPC32_TLSDESC` |
| * `R_X86_64_CODE_6_GOTTPOFF` |
| |
| |
| Changes to the OCaml bindings |
| ----------------------------- |
| |
| Changes to the Python bindings |
| ------------------------------ |
| |
| Changes to the C API |
| -------------------- |
| |
| * The following symbols are deleted due to the removal of the `x86_mmx` IR type: |
| |
| * `LLVMX86_MMXTypeKind` |
| * `LLVMX86MMXTypeInContext` |
| * `LLVMX86MMXType` |
| |
| * The following functions are added to further support non-null-terminated strings: |
| |
| * `LLVMGetNamedFunctionWithLength` |
| * `LLVMGetNamedGlobalWithLength` |
| |
| * The following functions are added to access the `LLVMContextRef` associated |
| with `LLVMValueRef` and `LLVMBuilderRef` objects: |
| |
| * `LLVMGetValueContext` |
| * `LLVMGetBuilderContext` |
| |
| * The new pass manager can now be invoked with a custom alias analysis pipeline, using |
| the `LLVMPassBuilderOptionsSetAAPipeline` function. |
| |
| * It is now also possible to run the new pass manager on a single function, by calling |
| `LLVMRunPassesOnFunction` instead of `LLVMRunPasses`. |
| |
| * Support for creating instructions with custom synchronization scopes has been added: |
| |
| * `LLVMGetSyncScopeID` to map a synchronization scope name to an ID. |
| * `LLVMBuildFenceSyncScope`, `LLVMBuildAtomicRMWSyncScope` and |
| `LLVMBuildAtomicCmpXchgSyncScope` versions of the existing builder functions |
| with an additional synchronization scope ID parameter. |
| * `LLVMGetAtomicSyncScopeID` and `LLVMSetAtomicSyncScopeID` to get and set the |
| synchronization scope of any atomic instruction. |
| * `LLVMIsAtomic` to check if an instruction is atomic, for use with the above functions. |
| Because of backwards compatibility, `LLVMIsAtomicSingleThread` and |
| `LLVMSetAtomicSingleThread` continue to work with any instruction type. |
| |
| * The `LLVMSetPersonalityFn` and `LLVMSetInitializer` APIs now support clearing the |
| personality function and initializer respectively by passing a null pointer. |
| |
| * The following functions are added to allow iterating over debug records attached to |
| instructions: |
| |
| * `LLVMGetFirstDbgRecord` |
| * `LLVMGetLastDbgRecord` |
| * `LLVMGetNextDbgRecord` |
| * `LLVMGetPreviousDbgRecord` |
| |
| * Added `LLVMAtomicRMWBinOpUSubCond` and `LLVMAtomicRMWBinOpUSubSat` to `LLVMAtomicRMWBinOp` enum for AtomicRMW instructions. |
| |
| Changes to the CodeGen infrastructure |
| ------------------------------------- |
| |
| Changes to the Metadata Info |
| --------------------------------- |
| |
| Changes to the Debug Info |
| --------------------------------- |
| |
| Changes to the LLVM tools |
| --------------------------------- |
| |
| * llvm-objcopy now supports the following options for Mach-O: |
| `--globalize-symbol`, `--globalize-symbols`, |
| `--keep-global-symbol`, `--keep-global-symbols`, |
| `--localize-symbol`, `--localize-symbols`, |
| `--skip-symbol`, `--skip-symbols`. |
| |
| Changes to LLDB |
| --------------------------------- |
| |
| * LLDB now supports inline diagnostics for the expression evaluator and command line parser. |
| |
| Old: |
| ``` |
| (lldb) p a+b |
| error: <user expression 0>:1:1: use of undeclared identifier 'a' |
| 1 | a+b |
| | ^ |
| error: <user expression 0>:1:3: use of undeclared identifier 'b' |
| 1 | a+b |
| | ^ |
| ``` |
| |
| New: |
| |
| ``` |
| (lldb) p a+b |
| ˄ ˄ |
| │ ╰─ error: use of undeclared identifier 'b' |
| ╰─ error: use of undeclared identifier 'a' |
| ``` |
| |
| * LLDB can now read the `fpmr` register from AArch64 Linux processes and core |
| files. |
| |
| * Program stdout/stderr redirection will now open the file with O_TRUNC flag, make sure to truncate the file if path already exists. |
| * eg. `settings set target.output-path/target.error-path <path/to/file>` |
| |
| * A new setting `target.launch-working-dir` can be used to set a persistent cwd that is used by default by `process launch` and `run`. |
| |
| * LLDB now parses shared libraries in parallel, resulting in an average 2x speedup when attaching (only available on Darwin platforms) and launching (available on all platforms). |
| |
| * On the command line, LLDB now limits tab completions to your terminal width to avoid wrapping. |
| |
| Old: |
| ``` |
| Available completions: |
| _regexp-attach -- Attach to process by ID or name. |
| _regexp-break -- Set a breakpoint using one of several shorthand |
| formats. |
| _regexp-bt -- Show backtrace of the current thread's call sta |
| ck. Any numeric argument displays at most that many frames. The argument 'al |
| l' displays all threads. Use 'settings set frame-format' to customize the pr |
| inting of individual frames and 'settings set thread-format' to customize th |
| e thread header. Frame recognizers may filter thelist. Use 'thread backtrace |
| -u (--unfiltered)' to see them all. |
| _regexp-display -- Evaluate an expression at every stop (see 'help |
| target stop-hook'.) |
| |
| ``` |
| |
| New: |
| ``` |
| Available completions: |
| _regexp-attach -- Attach to process by ID or name. |
| _regexp-break -- Set a breakpoint using one of several shorth... |
| _regexp-bt -- Show backtrace of the current thread's call ... |
| _regexp-display -- Evaluate an expression at every stop (see 'h... |
| ``` |
| |
| Changes to BOLT |
| --------------------------------- |
| |
| Changes to Sanitizers |
| --------------------- |
| |
| Other Changes |
| ------------- |
| |
| External Open Source Projects Using LLVM {{env.config.release}} |
| =============================================================== |
| |
| * 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). |