编译原理实验四 代码生成.doc

编译原理实验四 代码生成输入：语法树。输出：生成P代码存入codestrcodeindex。样例程序已经能生成P代码。文法：stmt_seq -statement ; stmt_seq | statementstatement-decl_stmt | assign_stmtdecl_stmt-type var_listtype-int |floatvar_list-id , var_list | idassign_stmt- id := expexp-exp + term | exp - term |termterm- term * factor | term * factor | factorfactor-id | num | ( exp )要求掌握理解程序设计方法。#include#include typedef enum MINUS,PLUS,TIMES,OVER,LPAREN,RPAREN,SEMI,ASSIGN,NUM,ID,INT,FLOAT,COMMA,DOLLAR tokentype;/*记号*/typedef enum stmtk,expk nodekind;typedef enum ifk,assignk,declk stmtkind;typedef enum opk,constk,idk expkind;typedef enum integer,real exptype;typedef struct treenode struct treenode * child3; struct treenode * sibling; nodekind nodek; exptype dtype ; union stmtkind stmt; expkind exp; kind; union tokentype op; int val; char * name; attr; treenode;typedef struct bucket char * name; exptype dtype; struct bucket * next; bucket;bucket * hashtable211;tokentype token=ID,ASSIGN,NUM,PLUS,NUM,TIMES,ID,SEMI,ID,ASSIGN,NUM,DOLLAR; char tokenstring30=ab,:=,12,+,5,*,x,;,xy,:=,34,$; int wordindex=0; /*以上两个数组的索引*/char codestr3030;int codeindex=0;treenode * t;treenode * decl();treenode * factor();treenode * term();treenode * exp();treenode * assign_stmt();treenode * stmt_seq();pretraverse(treenode *);expcode(treenode *);gencode(treenode *);main()int i; t=stmt_seq();pretraverse(t);gencode(t);for(i=0; isibling=q; p=q; return t;treenode * assign_stmt()treenode * t=(treenode *)malloc(sizeof(treenode); if(tokenwordindex=ID) t-nodek=stmtk; t-kind.stmt=assignk; =tokenstringwordindex; wordindex+; else printf(error); exit(1); if(tokenwordindex=ASSIGN) wordindex+; else printf(error); exit(1); t-child0=exp(); t-child1=NULL; t-child2=NULL; t-sibling=NULL; return t;treenode * exp()treenode * t; t=term(); while(tokenwordindex=PLUS)|(tokenwordindex=MINUS) treenode * p=(treenode *)malloc(sizeof(treenode); p-nodek=expk; p-kind.exp=opk; p-attr.op=tokenwordindex; p-child0=t; t=p; wordindex+; t-child1=term(); t-child2=NULL; t-sibling=NULL; return t;treenode * term()treenode * t=factor(); while(tokenwordindex=TIMES)|(tokenwordindex=OVER) treenode * p=(treenode *)malloc(sizeof(treenode); p-nodek=expk; p-kind.exp=opk; p-attr.op=tokenwordindex; p-child0=t; t=p; wordindex+; t-child1=factor(); t-child2=NULL; t-sibling=NULL; return t;treenode * factor()treenode * t; switch(tokenwordindex) case LPAREN : wordindex+; t=exp(); if(tokenwordindex=RPAREN) wordindex+; else printf(error); exit(1); break; case NUM : t=(treenode *)malloc(sizeof(treenode); t-nodek=expk; t-kind.exp=constk; t-attr.val=atoi(tokenstringwordindex); t-child0=NULL; t-child1=NULL; t-child2=NULL; t-sibling=NULL; wordindex+; break; case ID : t=(treenode *)malloc(sizeof(treenode); t-nodek=expk; t-kind.exp=idk; =tokenstringwordindex; wordindex+; break; default: printf(error); return t;pretraverse(treenode * t)if (t!=NULL) if (t-nodek=stmtk) printf(stmt-id:%sn,); if (t-nodek=expk & t-kind.exp=idk) printf(exp-id:%sn,); if (t-nodek=expk & t-kind.exp=opk) printf(exp-op:%dn,t-attr.op); if (t-nodek=expk & t-kind.exp=constk) printf(exp-val:%dn,t-attr.val); if(t-child0!=NULL) pretraverse(t-child0); if(t-child1!=NULL) pretraverse(t-child1); if(t-child2!=NULL) pretraverse(t-child2); if(t-sibling!=NULL) pretraverse(t-sibling); treenode * decl()treenode * p,* q,* t1; treenode * t=(treenode *)malloc(sizeof(treenode); t-nodek=stmtk; t-kind.stmt=declk; =tokenstringwordindex; t-child1=NULL; t-child2=NULL; wordindex+; if(tokenwordindex=ID) t1=(treenode *)malloc(sizeof(treenode); t-child0=t1; t1-nodek= expk; t1-kind.exp=idk; =tokenstringwordindex; t1-child0=NULL; t1-child1=NULL; t1-child2=NULL; t1-sibling=NULL; wordindex+; p=t1; while( tokenwordindex=COMMA) wordindex+; q=(treenode *)malloc(sizeof(treenode); q-nodek= expk; q-kind.exp=idk; =tokenstringwordindex; q-child0=NULL; q-child1=NULL; q-child2=NULL; q-sibling=NULL; p-sibling=q; wordindex+; p=q; return t; expcode(treenode * t)char * s1, * s2; if(t-child0!=NULL) expcode(t-child0); if(t-child1!=NULL) expcode(t-child1); if(t-nodek=expk & t-kind.exp=opk) if (t-attr.op=PLUS) strcpy(codestrcodeindex+,adi); if (t-attr.op=MINUS) strcpy(codestrcodeindex+,sbi); if (t-attr.op=TIMES) strcpy(codestrcodeindex+,mpi); if (t-attr.op=OVER) strcpy(codestrcodeindex+,ovi); if(t-nodek=expk & t-kind.exp=idk) strcpy(codestrcodeindex+,strcat(lod ,); if(t-nodek=expk & t-kind.exp=constk) strcpy(s1,ldc ); itoa(t-attr.val, s2,10); strcat(s1,s2); strcpy(codestrcodeindex+,s1); genco