LLVM’s ORC JIT APIs have undergone a major redesign over the last year to support compilation of multithreaded code and concurrent compilation within the JIT itself. Internally, ORC’s symbol resolution scheme has been replaced with a system that provides transactional, batch symbol queries. This new scheme both exposes opportunities for parallel compilation within the JIT, and provides a basis for synchronizing interdependent JIT tasks when they reach the JIT linker stage. Alongside this query system, a new “Responsibility” API is introduced to track compilation tasks and enforce graceful termination of the JIT (and JIT’d code) in the event of unrecoverable IPC/RPC failures or other errors. In this talk we will describe the new design, how the API has changed, and the implementation details of the new symbol resolution and responsibility schemes. We will also talk about new developments in the ORC C APIs, and discuss future directions for LLVM’s JIT APIs.
