[Openmp-commits] [PATCH] D108534: [OpenMP][Docs] add clang to LLVM_ENABLE_PROJECTS in build instructions

[Michael Kruse via Phabricator via Openmp-commits]

Meinersbur added a comment.

In D108534#2961444 <https://reviews.llvm.org/D108534#2961444>, @JonChesterfield wrote:

> However, that only runs reliably if clang uses the deviceRTL from the same monorepo hash. Some other clang will have different assumptions about the library. It's not sufficient to build the deviceRTL with the clang the user will run on host code. It really has to be the deviceRTL that came from the same checkout as the clang the user will use.
>
> This is difficult to specify reliably without requiring an exact match (e.g. burn the git sha into all the pieces and refuse to run if some differ) or bootstrapping. Enable_runtimes makes the bootstrap easy to get right.

At the risk of repeating myself:

- `$<TARGET_FILE:clang>` (if clang is compiled alongside) is the correct clang with the same monorepo hash.
  - The current implementation of libomptarget's LLVM_ENABLE_RUNTIMES makes any compiler with `CMAKE_C_COMPILER_ID` equals "clang" compile the deviceRTL.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D108534/new/

https://reviews.llvm.org/D108534