[flang-commits] [flang] [flang][Driver] Add support for -mllvm -print-pipeline-passes (PR #106141)

[Andrzej Warzyński via flang-commits]

banach-space wrote:

Thanks for the summary!

> `-fdebug-pass-manager` executes the underlying action, while this simply prints the pipeline and terminates. 

This is something that struggle with. It is basically making this one flag (which is meant as LLVM's internal option) a very _very_ special flower. We should avoid that. This was already raised when this behaviour was introduced in Clang:
* https://reviews.llvm.org/D127221 

Here's one follow-up question - could you compare the output from `-mllvm -print-pipeline-passes` and `-fdebug-pass-manager` and paste it here? Is it very different and is the former the preferred format? If yes, why not update `-fdebug-pass-manager` accordingly (in both Clang and Flang)? Is "stopping" the compilation the desired behaviour here?

I'm 100% supportive of improving the end-user and developer's experience, but I want to make sure that there's no other, more canonical way to achieve the same. Right now it feels that indeed there is :)

https://github.com/llvm/llvm-project/pull/106141