173600880b
While the infrastructure for declare target to/enter and link for variables exists in the MLIR dialect and at the Flang level, the current lowering from MLIR -> LLVM IR isn't in place, it's only in place for variables that have the link clause applied. This PR aims to extend that lowering to an initial implementation that incorporates declare target to as well, which primarily requires changes in the OpenMPToLLVMIRTranslation phase. However, a minor addition to the OpenMP dialect was required to extend the declare target enumerator to include a default None field as well. This also requires a minor change to the Flang lowering's MapInfoFinlization.cpp pass to alter the map type for descriptors to deal with cases where a variable is marked declare to. Currently, when a descriptor variable is mapped declare target to the descriptor component can become attatched, and cannot be updated, this results in issues when an unusual allocation range is specified (effectively an off-by X error). The current solution is to map the descriptor always, as we always require an up-to-date version of this data. However, this also requires an interlinked PR that adds a more intricate type of mapping of structures/record types that clang currently implements, to circumvent the overwriting of the pointer in the descriptor. 3/3 required PRs to enable declare target to mapping, this PR should pass all tests and provide an all green CI. Co-authored-by: Raghu Maddhipatla raghu.maddhipatla@amd.com
The LLVM/Offload Subproject
The Offload subproject aims at providing tooling, runtimes, and APIs that allow users to execute code on accelerators or other "co-processors" that may or may not match the architecture of their "host". In the long run, all kinds of targets are in scope of this effort, including but not limited to: CPUs, GPUs, FPGAs, AI/ML accelerators, distributed resources, etc.
For OpenMP offload users, the project is ready and fully usable. The final API design is still under development. More content will show up here and on our webpage soon. In the meantime, people are encouraged to participate in our meetings (see below) and check our development board as well as the discussions on Discourse.
Meetings
Every second Wednesday, 7:00 - 8:00am PT, starting Jan 24, 2024. Alternates with the OpenMP in LLVM meeting. invite.ics Meeting Minutes and Agenda