Google Git
Sign in
llvm / llvm-project / f38c83c582cb9de04556c32bc6b18ad1aeda74af
commitf38c83c582cb9de04556c32bc6b18ad1aeda74af[log] [tgz]
authorJonathan Thackray <jonathan.thackray@arm.com>Mon Aug 18 14:41:41 2025 +0100
committerGitHub <noreply@github.com>Mon Aug 18 14:41:41 2025 +0100
treefc4fdba66ef481466ce22750d7bf8f821f1b1509
parent31d2db2a68ae6e810f3e5532b521b913b50cc25e [diff]
[AArch64][llvm] Disassemble instructions in `SYS` alias encoding space more correctly (#153905)

For instructions in the `SYS` alias encoding space which take no
register operands, and where the unused 5 register bits are not all set
(0x31, 0b11111), then disassemble to a `SYS` alias and not the
instruction, since it is not considered valid.

This is because it is specified in the Arm ARM in text similar to this
(e.g. page C5-1037 of DDI0487L.b for `TLBI ALLE1`, or page C5-1585 for
`GCSPOPX`):
```
  Rt should be encoded as 0b11111. If the Rt field is not set to 0b11111,
  it is CONSTRAINED UNPREDICTABLE whether:
    * The instruction is UNDEFINED.
    * The instruction behaves as if the Rt field is set to 0b11111.
```

Since we want to follow "should" directives, and not encourage undefined
behaviour, only assemble or disassemble instructions considered valid.
Add an extra test-case for this, and all existing test-cases are
continuing to pass.
2 files changed
tree: fc4fdba66ef481466ce22750d7bf8f821f1b1509
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. polly/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  29. .clang-format-ignore
  30. .clang-tidy
  31. .git-blame-ignore-revs
  32. .gitattributes
  33. .gitignore
  34. .mailmap
  35. CODE_OF_CONDUCT.md
  36. CONTRIBUTING.md
  37. LICENSE.TXT
  38. pyproject.toml
  39. README.md
  40. SECURITY.md
README.md

The LLVM Compiler Infrastructure

OpenSSF Scorecard OpenSSF Best Practices libc++

Welcome to the LLVM project!

This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.

C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

Getting the Source Code and Building LLVM

Consult the Getting Started with LLVM page for information on building and running LLVM.

For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting in touch

Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.

The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.