LLVM 8.0.0 Release Notes


These are in-progress notes for the upcoming LLVM 8 release. Release notes for previous releases can be found on the Download Page.


This document contains the release notes for the LLVM Compiler Infrastructure, release 8.0.0. 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 Subversion 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.

Non-comprehensive list of changes in this release

  • The llvm-cov tool can now export lcov trace files using the -format=lcov option of the export command.
  • The add_llvm_loadable_module CMake macro has been removed. The add_llvm_library macro with the MODULE argument now provides the same functionality. See Writing an LLVM Pass.
  • For MinGW, references to data variables that might need to be imported from a dll are accessed via a stub, to allow the linker to convert it to a dllimport if needed.
  • Added support for labels as offsets in .reloc directive.

Changes to the AArch64 Target

  • Added support for the .arch_extension assembler directive, just like on ARM.

Changes to the ARM Backend

During this release …

Changes to the Hexagon Target

  • Added support for Hexagon/HVX V66 ISA.

Changes to the MIPS Target

  • Improved support of GlobalISel instruction selection framework.
  • Implemented emission of R_MIPS_JALR and R_MICROMIPS_JALR relocations. These relocations provide hints to a linker for optimization of jumps to protected symbols.
  • ORC JIT has been supported for MIPS and MIPS64 architectures.
  • Assembler now suggests alternative MIPS instruction mnemonics when an invalid one is specified.
  • Improved support for MIPS N32 ABI.
  • Added new instructions (pll.ps, plu.ps, cvt.s.pu, cvt.s.pl, cvt.ps, sigrie).
  • Numerous bug fixes and code cleanups.

Changes to the PowerPC Target

During this release …

Changes to the X86 Target

  • Machine model for AMD bdver2 (Piledriver) CPU was added. It is used to support instruction scheduling and other instruction cost heuristics.

Changes to the AMDGPU Target

During this release …

Changes to the AVR Target

During this release …

Changes to the WebAssembly Target

The WebAssembly target is no longer “experimental”! It’s now built by default, rather than needing to be enabled with LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.

The object file format and core C ABI are now considered stable. That said, the object file format has an ABI versioning capability, and one anticipated use for it will be to add support for returning small structs as multiple return values, once the underlying WebAssembly platform itself supports it. Additionally, multithreading support is not yet included in the stable ABI.

External Open Source Projects Using LLVM 8

Zig Programming Language

Zig is a system programming language intended to be an alternative to C. It provides high level features such as generics, compile time function execution, and partial evaluation, while exposing low level LLVM IR features such as aliases and intrinsics. Zig uses Clang to provide automatic import of .h symbols, including inline functions and simple macros. Zig uses LLD combined with lazily building compiler-rt to provide out-of-the-box cross-compiling for all supported targets.

Additional Information

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 Subversion 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.