[llvm] [llvm/mc] Add support for sdata8 for FDE CIE (PR #174508)

[Alexis Engelke via llvm-commits]

aengelke wrote:

> This is related to https://github.com/llvm/llvm-project/pull/174486 and part of a larger effort to support larger binaries (>2GiB .text) while still retaining the medium code-model.

Won't this break small data accesses? The psABI describes that in the medium code model, small data is still within +-2GiB and can be (is currently) accessed using 32-bit displacements. Shouldn't this either need a new code model or change the code generated for large? (IIUC, call/jmp in the large code model should be ok if the linker supports thunk insertion?)

https://github.com/llvm/llvm-project/pull/174508