基于GCC的VLIW编译系统研究

Research on GCC Based VLIW Compiler System

VLIW机器在单个机器周期中同时发射并执行多个的并行操作，从而获得较高的指令级并行度，这些操作之间的依赖分析和调度工作则被完全交给相应的编译器执行，因此VLIW的并行性能能否充分发挥取决于VLIW体系结构相关编译器的质量。GNU开发的GCC是被最广泛使用的编译系统之一，它具有多语言、多平台支持的能力和开放的结构，能够运用各种成熟的常规编译优化技术生成高效的代码。文章分析了VLIW及GCC的结构特点，提出了一种基于GCC的VLIW编译系统设计方案，利用GCC进行RTL中间代码一级的体系结构无关优化和少量体系结构相关优化，在汇编代码一级针对VLIW结构进行体系结构相关的优化，从而充分利用GCC的成熟编译技术快速开发高效的VLIW多语言编译系统。

： VLIW machine achieves high ILP by issuing and executing multiple operations in one machine cycle．However，dependence analysis and scheduling of these operations are carried out by the compiler．The parallel performance heavily depends on the quality of compilers on VLIW architecture．GCC is one of the most broadly used compiler systems，it is capable of supporting multi－language and multi－platform and has an open architecture．It uses mature conventional compiler optimization technologies to generate code with high efficiency．After analyzing the architecture characters of VLIW and GCC，this paper develops a design of GCC－based compiler system of VLIW，in which all the architecture－independent and some of architecture－dependent optimizations are done by GCC in RTL intermediate code level，whereas VLIW architecture－dependent optimizations are done on the assembly code level．This design can well exploit mature compiler optimization technology and rapidly develop high－performance VLIW multi－language compiler systems．