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llvm / llvm-project / c5b3fe209408c89c1ca21f103a8fd45fb48c3138
commitc5b3fe209408c89c1ca21f103a8fd45fb48c3138[log] [tgz]
authorAlan Zhao <ayzhao@google.com>Mon Mar 31 09:42:34 2025 -0700
committerGitHub <noreply@github.com>Mon Mar 31 09:42:34 2025 -0700
tree3bcc5f3f254813b6b6f30b555071b6e962bef311
parent94b04b411903e97bd228c6bdbdb845c29f6de6a1 [diff]
[clang] Automatically add the `returns_twice` attribute to certain functions even if `-fno-builtin` is set (#133511)

Certain functions require the `returns_twice` attribute in order to
produce correct codegen. However, `-fno-builtin` removes all knowledge
of functions that require this attribute, so this PR modifies Clang to
add the `returns_twice` attribute even if `-fno-builtin` is set. This
behavior is also consistent with what GCC does.

It's not (easily) possible to get the builtin information from
`Builtins.td` because `-fno-builtin` causes Clang to never initialize
any builtins, so functions never get tokenized as functions/builtins
that require `returns_twice`. Therefore, the most straightforward
solution is to explicitly hard code the function names that require
`returns_twice`.

Fixes #122840
3 files changed
tree: 3bcc5f3f254813b6b6f30b555071b6e962bef311
  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. libunwind/
  16. lld/
  17. lldb/
  18. llvm/
  19. llvm-libgcc/
  20. mlir/
  21. offload/
  22. openmp/
  23. polly/
  24. pstl/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  29. .clang-tidy
  30. .git-blame-ignore-revs
  31. .gitattributes
  32. .gitignore
  33. .mailmap
  34. CODE_OF_CONDUCT.md
  35. CONTRIBUTING.md
  36. LICENSE.TXT
  37. pyproject.toml
  38. README.md
  39. 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.

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.

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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.

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