fa9e90f5d2
This patch overhauls the `libomptarget` and plugin interface. Currently, we define a C API and compile each plugin as a separate shared library. Then, `libomptarget` loads these API functions and forwards its internal calls to them. This was originally designed to allow multiple implementations of a library to be live. However, since then no one has used this functionality and it prevents us from using much nicer interfaces. If the old behavior is desired it should instead be implemented as a separate plugin. This patch replaces the `PluginAdaptorTy` interface with the `GenericPluginTy` that is used by the plugins. Each plugin exports a `createPlugin_<name>` function that is used to get the specific implementation. This code is now shared with `libomptarget`. There are some notable improvements to this. 1. Massively improved lifetimes of life runtime objects 2. The plugins can use a C++ interface 3. Global state does not need to be duplicated for each plugin + libomptarget 4. Easier to use and add features and improve error handling 5. Less function call overhead / Improved LTO performance. Additional changes in this plugin are related to contending with the fact that state is now shared. Initialization and deinitialization is now handled correctly and in phase with the underlying runtime, allowing us to actually know when something is getting deallocated. Depends on https://github.com/llvm/llvm-project/pull/86971 https://github.com/llvm/llvm-project/pull/86875 https://github.com/llvm/llvm-project/pull/86868
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