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llvm / llvm-project / db0f754c5af8e6c96770533520bf8b17fc0dc977
commitdb0f754c5af8e6c96770533520bf8b17fc0dc977[log] [tgz]
authorJoseph Huber <huberjn@outlook.com>Fri Apr 18 07:43:31 2025 -0500
committerGitHub <noreply@github.com>Fri Apr 18 07:43:31 2025 -0500
treecdbda5ebf091261c2816d23abda3f03dd8a637c0
parent3ed83630b263f667bacd1ef1a65f26d8665c282e [diff]
[OpenMP] Remove 'libomptarget.devicertl.a' fatbinary and use static library (#126143)

Summary:
Currently, we build a single `libomptarget.devicertl.a` which is a
fatbinary. It is a host object file that contains the embedded archive
files for both the NVIDIA and AMDGPU targets. This was done primarily as
a convenience due to naming conflicts. Now that the clang driver for the
GPU targets can appropriate link via the per-target runtime-dir, we can
just make two separate static libraries and remove the indirection.

This patch creates two new static libraries that get installed into
```
/lib/amdgcn-amd-amdhsa/libomp.a
/lib/nvptx64-nvidia-cuda/libomp.a
```
for AMDGPU and NVPTX respectively. The link job created by the linker
wrapper now simply needs to do `-lomp` and it will search those
directories and link those static libraries. This requires far less
special handling.

This patch is a precursor to changing the build system entirely to be a
runtimes based one. Soon this target will be a standard `add_library`
and done through the GPU runtime targets.

NOTE that this actually does remove an additional optimization step.
Previously we merged all of the files into a single bitcode object and
forcibly internalized some definitions. This, instead, just treats them
like a normal static library. This may possibly affect performance for
some files, but I think it's better overall to use static library
semantics because it allows us to have an 'include-what-you-use'
relationship with the library.

Performance testing will be required. If we really need the merged blob
then we can simply pack that into a new static library.
6 files changed
tree: cdbda5ebf091261c2816d23abda3f03dd8a637c0
  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-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
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