aec735cf47
This PR attempts to fix common block mapping for regular mapping of these types as well as when they have been marked as "declare target link". This PR should allow correct mapping of both the members of a common block and the full common block via its block symbol. The main changes were some adjustments to the Fortran OpenMP lowering to HLFIR/FIR, the lowering of the LLVM+OpenMP dialect to LLVM-IR and adjustments to the way the we handle target kernel map argument rebinding inside of the OMPIRBuilder. For the Fortran OpenMP lowering were two changes, one to prevent the implicit capture of common block members when the common block symbol itself has been marked and the other creates intermediate member access inside of the target region to be used in-place of those external to the target region, this prevents external usages breaking the IsolatedFromAbove pact. In the latter case, there was an adjustment to the size calculation for types to better handle cases where we pass an array as the type of a map (as opposed to the bounds and the type of the element), which occurs in the case of common blocks. There is also some adjustment to how handleDeclareTargetMapVar handles renaming of declare target symbols in the module to the reference pointer, now it will only apply to those within the kernel that is currently being generated and we also perform a modification to replace constants with instructions as necessary as we cannot replace these with our reference pointer (non-constant and constants do not mix nicely). In the case of the OpenMPIRBuilder some changes were made to defer global symbol rebinding to kernel arguments until all other arguments have been rebound. This makes sure we do not replace uses that may refer to the global (e.g. a GEP) but are themselves actually a separate argument that needs bound. Currently "declare target to" still needs some work, but this may be the case for all types in conjunction with "declare target to" at the moment.
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.
The project is just starting and the design is still not ironed out. 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