这是编译原理的源代码，涉及了编译原理的各个过程：词法分析，LL1语法分析，语义分析，中间代码生成，中间代码优化（常表达式优化，公共表达式优化，循环不变式优化），中间代码生成目标代码，目标代码的解释执行，详细地阐述了一个编译器的设计和实现。它是大纲教学，课程设计良好的示范，也是编程爱好者提高的好参考，其中这是中间代码优化部分。希望尽早的开通我的帐号，和大家多多交流，成为热爱编程的好朋友。-this principle is to compile the source code, the compiler principles involved in various processes : lexical analysis, LL1 syntax analysis, semantic analysis and code generation and code optimization (regular expression optimization, public expression optimization, optimization loop invariant), intermediate code generation target code goal of the interpretation and implementation of code, described in detail a compiler design and implementation. It is the outline of teaching, curriculum design good model, as well as programming enthusiasts to raise a good reference, it is the middle part of code optimization. Early hopes for the opening of my account, and we interact more, as a good friend who love programming.