A high quality compiler tool for application-specific instruction-set processors with library and parallel supports

Developing a high quality compiler tool for application-specific instruction-set processors (ASIPs) including DSP for multimedia application is challenging. The specialization in ASIPs often calls for extensions at the high-level languages to allow the designers to exploit the specialized capabilities. This in turn requires the frontend of the compiler to handle the new syntax and carry the intentions of the designers across to the compiler backend implementations. The backend implementations also require extra efforts for optimized uses of the specialize features of ASIPs. Meanwhile, because of the diversity of the application, it is necessary to make full use of the compiler to complete supports and to make up some shortages of ASIP processors, the corresponding library functions are increased to support of certain operations, such as floating point arithmetic that may not be supported in ASIPs. With the development of the embedded parallelism, the advanced ASIP compilers need the support of parallelism for future application. This paper describes the High-performance C Compiler (HCC) and its specific implementation for an industrial ASIP and its family processors. HCC is a C language compiler extended and retargeted from GCC. A compiler extension framework is proposed processing programming syntax extensions of standard ANSI C for the ASIPs. With target-specific implementation, the adding optimized arithmetic functions library and chips definition file (CDF) as well as the header files for corresponding ASIPs, HCC compiler could be enhanced for the processing capabilities of target processors. Finally, this paper describes a new compiler static allocation and scheduling scheme for loop parallelization based on the OpenMP specification to improve the load imbalance. We have conducted analysis and extensive experiments to verify the correctness and effectiveness of the HCC compiler with the presented ideas. The results show that HCC compiler has a stable performance with excellent codes quality and it has been used in market.