[llvm] [CodeGen] Use byte offsets and ptradd in ShadowStackGCLowering (PR #178436)

[via llvm-commits]

isuckatcs wrote:

> This PR is a step in the direction of the planned eventual deprecation of getAllocatedType

This is unrelated to the particular issue that we have. The issue is `llvm.gcroot` allows  non-pointer roots, which your changes ignore and we have a regression.

You can think the check should be removed. You can even remove it if you want to for the reasons you mentioned. The BEHAVIOR, however, should not change.

To justify merging this PR you should reason for why we should DISABLE non-pointer GC roots.

IIUC you say that `alloca->getAllocatedType()` is wrong. This has nothing to do with what kind of GC roots are accepted. It only says that the way the roots are verified is wrong, and a DIFFERENT way should be found. The GC has nothing to do with it.

https://github.com/llvm/llvm-project/pull/178436