Hexe, which stands for Heterogeneous Execution Engine, is an new compiler component that integrates with the LLVM infrastructure. It targets efficient computation on heterogeneous platforms by allowing the automatic offloading of workloads on computational accelerators, such as Graphics Processing Units (GPUs) or Digital Signal Processors(DSPs).
The workloads we consider for offloading are either explicitly annotated by the programmer or automatically detected by static compiler analysis and runtime checks. Our infrastructure operates at the level of LLVM intermediate representation and effectively supports multiple source languages.
Hexe consists of a set of compiler passes and a runtime environment. The compiler passes perform the required code analysis and transformations to enable workload offloading. The runtime environment manages data transfers and synchronization operations, and performs dynamic workload scheduling.
We consider a diverse set of heterogeneous systems ranging from mobile devices equipped with arm based multi-core CPUs, embedded GPUs and DSPs to data center nodes consisting of x86 multi-cores and high-end GPUs. Hexe has a modular design where new accelerator types and programming environments can be supported via a plugin interface. We also consider interoperability between Hexe and modern JIT technologies, such as LLVM MCJIT.
