Summary:
When we were first porting to COV5, this lead to some ABI issues due to
a change in how we looked up the work group size. Bitcode libraries
relied on the builtins to emit code, but this was changed between
versions. This prevented the bitcode libraries, like OpenMP or libc,
from being used for both COV4 and COV5. The solution was to have this
'none' functionality which effectively emitted code that branched off of
a global to resolve to either version.
This isn't a great solution because it forced every TU to have this
variable in it. The patch in
https://github.com/llvm/llvm-project/pull/131033 removed support for
COV4 from OpenMP, which was the only consumer of this functionality.
Other users like HIP and OpenCL did not use this because they linked the
ROCm Device Library directly which has its own handling (The name was
borrowed from it after all).
So, now that we don't need to worry about backward compatibility with
COV4, we can remove this special handling. Users can still emit COV4
code, this simply removes the special handling used to make the OpenMP
device runtime bitcode version agnostic.
Fixes the DeviceRTL compilation to ensure it is ABI agnostic. Uses
already available global variable "oclc_ABI_version" instead of
"llvm.amdgcn.abi.verion".
It also adds some minor fields in ImplicitArg structure.
Summary:
We use the `llvm.amgcn.abi.version` varaible to control code generation.
This is emitted in every module now to indicate what should be used when
compiling. Previously, the logic caused us to emit an external reference
to this variable when creating the code for the `none` type. This would
then cause us not to emit the actual definition. This patch refines the
logic to create the external reference, and then update it if it is
found unset by the time we emit the global. I had to remove the
reference to `GetOrCreateLLVmGlobal` because it did not accept the
proper address space.
