Heterogeneous multi-core processor is proposed to accelerate applications using an application-specific hardware, such as graphics processing unit (GPU). However, heterogeneous multi-core processor is difficult to program. Therefore, OpenCL (Open Computing Language) standard recently has been proposed to reduce the difficulty. A program of OpenCL mainly consists of the host code (executed on CPU) and the device code (executed on GPU or other accelerators). LLVM (Low Level Virtual Machine) is a compiler infrastructure and supports a variety of front-ends into LLVM IR (Intermediate Representation). To help translate programs written by different programming languages of LLVM front-ends to OpenCL, this work defines some extensions of LLVM IR to represent the kernel function of OpenCL. Furthermore, a translation framework is designed and implemented to translate annotated LLVM IR to OpenCL kernel function.