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llvm / llvm-project / a82b97c524e851b0807b95c34a2154a2cbce9bdf
commita82b97c524e851b0807b95c34a2154a2cbce9bdf[log] [tgz]
authorFabian Parzefall <parzefall@meta.com>Wed Dec 03 18:29:24 2025 -0800
committerGitHub <noreply@github.com>Thu Dec 04 10:29:24 2025 +0800
tree5a99c8e8f3999ebe50e2daa5fc63aff5f01cb8a4
parent5b30750893ce3e005c5b1f7da963ab0adcf4cb61 [diff]
[CodeGen] Fix lpad padding at section start after empty block (#112595)

If a landing pad is at the very start of a split section, it has to be
padded by a nop instruction. Otherwise its offset is marked as zero in
the LSDA, which means no landing pad (leading it to be skipped).

LLVM already handles this. If a landing pad is the first machine block
in a section, a nop is inserted to ensure a non-zero offset. However, if
the landing pad is preceeded by an empty block, the nop would be
omitted.

To fix this, this patch adds a field to machine blocks indicating
whether this block contains the first instruction in its section. This
variable is then used to determine whether to emit the padding.

Co-authored-by: Jinjie Huang <huangjinjie@bytedance.com>
2 files changed
tree: 5a99c8e8f3999ebe50e2daa5fc63aff5f01cb8a4
  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. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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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.

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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.

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