9155b318f2
This PR adds deferral of descriptor maps until they are necessary for assumed dummy argument types. The intent is to avoid a problem where a user can inadvertently map a temporary local descriptor to device without their knowledge and proceed to never unmap it. This temporary local descriptor remains lodged in OpenMP device memory and the next time another variable or descriptor residing in the same stack address is mapped we incur a runtime OpenMP map error as we try to remap the same address. This fix was discussed with the OpenMP committee and applies to OpenMP 5.2 and below, future versions of OpenMP can avoid this issue via the attach semantics added to the specification.
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