[libcxx-commits] [PATCH] D137451: [CMake] Use LLVM_TARGET_TRIPLE in runtimes

[Petr Hosek via Phabricator via libcxx-commits]

phosek added a comment.

In D137451#3957333 <https://reviews.llvm.org/D137451#3957333>, @daltenty wrote:

> This patch seem to do a bit more than it's description implies. It makes `LLVM_DEFAULT_TARGET_TRIPLE` no longer an valid option on the `runtimes` path:
>
>   CMake Warning:
>     Manually-specified variables were not used by the project:
>   
>       LLVM_DEFAULT_TARGET_TRIPLE
>
> Is this intended? Currently `LLVM_DEFAULT_TARGET_TRIPLE` is the only option we actually document for changing the target triple (https://llvm.org/docs/CMake.html), so now the support options seem kind of inconsistent (though I don't fully grok the intended distinction between  `LLVM_DEFAULT_TARGET_TRIPLE` and `LLVM_TARGET_TRIPLE`, which may be part of the problem).

`LLVM_DEFAULT_TARGET_TRIPLE` is the default value that's used by tools like `clang` or `llc` when you don't explicitly specify `--target` or `--triple`. `LLVM_TARGET_TRIPLE` is the target triple we're building for. `LLVM_DEFAULT_TARGET_TRIPLE` is used as a the default value for `LLVM_TARGET_TRIPLE` but they're independent.

I couldn't come up with a use case for `LLVM_DEFAULT_TARGET_TRIPLE` in the runtimes build which is why I dropped it, but I'm open to revisiting that if you have other suggestions. I can also update the documentation to make sure this difference is covered.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137451/new/

https://reviews.llvm.org/D137451