Consider only targets where `MCAsmInfo::ExceptionsType == ExceptionHandling::None`
and that support CFI (when `MCAsmInfo::UsesCFIForDebug` is set to true):
currently, only AMDGPU.
This patch enables the emission of CFI information in the .eh_frame
section when the uwtable attribute is present on a function.
Before, we could generate CFI information for debugging puproses only.
This patch prepares AMDGPU to support collecting GPU stack traces in the future.
I did a first implementation (https://reviews.llvm.org/D139024)
but at the time I had not realized that no other platform used
`UsesCFIForDebug`.
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D151806
abe6ecd7e5