[lld-macho] Fix branch relocations with addends to target actual function (#177430)

When a branch relocation has a non-zero addend (e.g., `bl _func+16`),
the linker was incorrectly computing `stub_address + addend` instead of
`function_address + addend`. This caused the branch to land in the wrong
location (past the stub section) rather than at the intended interior
point of the function.

The fix checks for non-zero addends on branch relocations and uses the
actual symbol VA in those cases. This makes sense semantically—branching
to an interior offset implies reliance on the original function's
layout, which an interposed replacement wouldn't preserve anyway.

Added test `arm64-branch-addend-stubs.s` that verifies the correct
behavior using `-flat_namespace` (which makes local symbols interposable
and thus routed through stubs).

[Assisted-by](https://t.ly/Dkjjk): Cursor IDE + claude-opus-4.5-high
2 files changed
tree: df67acf518ca02b41a426f135ab285b338e4e93f
  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.

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.

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