O2render: An OpenCL-to-Renderscript translator for porting across various GPUs or CPUs

More than half-a-billion Android devices are world's most impactful real-time, interactive multimedia systems that are open-sourced. Google introduced Renderscript language and runtime in Android releases starting in 2011. Renderscript delivers performance and portability without losing usability. However, it is difficult to reuse software written in existing compute languages such as OpenCL. Thus, we develop the O2render system to enable OpenCL programs on Android devices. We analyze fundamental differences between OpenCL and Renderscript, and present our design of a translator between them using low-level virtual machine (LLVM). We extend LLVMs frontend, Clang, and show that we achieve about the same performance in Renderscript with minimal translation overhead.