[all-commits] [llvm/llvm-project] c354ee: [libc][GPU] Fix dependencies for externally instal...

[Joseph Huber via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c354ee8d1822907f9e8fb464de149e12af1d5081
      https://github.com/llvm/llvm-project/commit/c354ee8d1822907f9e8fb464de149e12af1d5081
  Author: Joseph Huber <35342157+jhuber6 at users.noreply.github.com>
  Date:   2023-09-18 (Mon, 18 Sep 2023)

  Changed paths:
    M libc/cmake/modules/LLVMLibCObjectRules.cmake

  Log Message:
  -----------
  [libc][GPU] Fix dependencies for externally installed stub files (#66653)

Summary:
The GPU build has a lot of magic around how we package the output.
Generally, the GPU needs to exist as a secondary fatbinary image for
offloading languages. This is because offloading languages pretend like
offloading to an accelerator is a single file. This then needs to be put
into a single file to make it mesh with the existing build
infrastructure. To work with this, the `libc` makes an installed version
of the library that simply embeds the GPU code into an empty stub file.

This wasn't being updated correctly, which lead to the installed `libc`
static library not being updated correctly when the underlying file was
changed. The previous behaviour only updated when the entrypoint itself
was modified, but not any of its headers. By adding a dependcy on the
actual *object* file we should now capture the regular CMake semantics.