编译器的设计和实现1.pptVIP

编译器的设计与实现;课程描述;一个简单的编译器的设计与实现;1 语言;1.1简单的C 语言的文法;expression→ ID = expression | simple-expression simple-expression→ additive-expression [ relop additive-expression ] relop → | = | | = | == | != additive-expression→ term [( + | - ) term ] term→ factor [ ( * | / ) factor ] factor→ ( expression )| ID | call | NUM call→ ID( args ) args→ expression { , expression } | empty;1.2程序举例;1.3进一步的扩展;2 目标机器建模;2.1 CPU的设计;2.2存储器组织;;2.3目标机器模型;数据结构;2.4指令系统;指令集举例;目标代码数据结构;大纲;3 编译程序的实现;简单回顾－编译的各个阶段;示例源代码;3.1词法分析;单词符号是什么？;如何表示单词符号？;如何表示单词符号？;示例;词法分析器的实现;S;实现代码; case scanState. INID: if(!Char.IsLetter(ch)!Char.IsDigit(ch)) { ungetNextChar(); tokType=TokenType.ID; state=scanState.DONE; } break; case scanState.INNUM: if(!Char.IsDigit(ch)){ ungetNextChar(); tokType=TokenType.NUMBER; state=scanState.DONE; } break; …… } //end_switch str+=ch; //记录当前正在判断的单词符号串 } //end_while Token tok= new Token(); tok.TType = tokType; tok.Str = str; return tok; };3.2语法分析;简单的C 语言的文法;expression→ ID = expression | simple-expression simple-expression→ additive-expression [ relop additive-expression ] relop → | = | | = | == | != additive-expression→ term [( + | - ) term ] term→ factor [ ( * | / ) factor ] factor→ ( expression )| ID | call | NUM call→ ID( args ) args→ expression { , expression } | empty;示例;语句if(ab) a = a-b;的语法分析树;对应的语法分析子程序;语法分析树与抽象语法树;语句if(ab) a = a-b;的抽象语法树;3.3抽象语法树与中间表示;抽象语法树 节点表示;;抽象语法树 节点表示;;;示例;语法分析器的实现;语法树节点设计;语法树节点设计;语法分析器的实现;TreeNode var_decl() { TreeNode retnode, nextnode, curnode; retnode = curnode; retnode.NType = curnode.NType = NodeType.VarDecl; While(curtoken.TType!=TokenType.SEMI) { Switch(curtoken.TType) { case TokenType.INT: match(TokenType.INT); break; Case TokenType.ID: nextnode.NodeStr = curtoken.str; //nextnode.IsArray = 0; nextnode.ArraySize = 0; 数组？ curnode.Sibling = nextnode; curnode = nextnode; match(TokenType.ID); break; case TokenType.COMMA: match(Toke