[PATCH][Middle-end][Version 4]Add a new option to control inlining only on static functions

[Alexander Monakov]

On Fri, 21 Sep 2018, Qing Zhao wrote:
> +2018-09-20  Qing Zhao  <qing.zhao@oracle.com>
> +
> +	* cif-code.def (FUNCTION_EXTERN): New CIFCODE.
> +	* common.opt (-finline-only-static): New option.
> +	* doc/invoke.texi: Document -finline-only-static.
> +	* ipa-inline.c (can_inline_edge_p): Control inlining based on
> +	function's linkage. 

Note, I am not a reviewer.

In my opinion, there's a problem with the patch that it looks like an ad-hoc,
incomplete solution. You said you need this change to help with building
livepatching-capable kernels, but it's not clear what exactly the issue with
inlining non-static functions is. Can you describe how the workflow looks like
so code duplication due to inlining static functions is not an issue, but
inlining non-static functions is a problem? Does using existing
-fno-inline-functions flag achieve something useful for your usecase?

Please always make it clear what problem the patch is intended to solve and help
reviewers see the connection between the problem and your solution. Look how the
"XY problem" effect applies partially in this situation.

https://en.wikipedia.org/wiki/XY_problem
http://xyproblem.info/

Alexander