[PATCH] D123198: [LibCalls] Add argument extension attributes to more functions.

Mon Apr 11 01:56:09 PDT 2022

xbolva00 added a comment.

In D123198#3442063 <https://reviews.llvm.org/D123198#3442063>, @jonpa wrote:

>> BuildLibCalls does not run under -O0 afaik .. so you wont get these attrs. So I dont think this is a correct place if my assumption holds.
>
> I am quite sure there are more places to handle, but fixing BuildLibCalls seems like a step in the right direction, wouldn't you agree? This is an existing problem we are trying to fix by carefully finding and handling all call sites throughout the code base.

I dont stiĺ think this is a correct place.

If this attribute is required for correctness, you should write simple pass which adds this atrribute very soon in pipeline and runs even under -O0. Or @efriedma may propose something…

>> And I also think that things will break for you if somebody uses eg. -fno-builtin-memccpy .. you will not get this ext attribute.
>
> I would be very grateful if you helped with this work by filing bug reports with test cases, and maybe even patches...

This is by design - if -ifno-builtin-xxx is used, a libcall is not annotated with any attribute here. This works fine and you are misusing BuildLibCalls and the solution is not to change when and how BuildLibCalls runs.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D123198/new/

https://reviews.llvm.org/D123198