TINY部分源码分析报告

1、精品资料TINY源码分析一、文件概述MAIN.C:主函数GLOBALS.H:全局定义的文件SCAN.C/SCAN.H:词法分析PARSE.C/PARSE.H:语法分析UTIL.C/UTIL.H:构造树SYMTAB.C/SYMTAB.H:符号表CGEN.C/CGEN.H:生成"汇编代码"CODE.C/CODE.H:这个只是用来把分析过程输出到屏幕的.二、各个文件的分析1.MAIN.C:主要有三个FILE*句柄:source-源代码文件。listing-显示分析过程的文件，这里重定向到stdout。code-目标汇编代码文件。从该文件中可知程序运行的流程：检查参数正确否（tin

2、y.exefilename）->构造语法树（调用parse函数）->根据语法树生成代码（调用codeGen函数，该函数又调用cGen函数。2.GLOBALS.H:定义了关键字个数8个。定义了关键字，运算符等内容的枚举值。定义了语句类型的枚举值，这个决定树的结点。可编辑修改定义了变量类型(也就三种，void,integer,boolean)。定义了树的节点-这个最重要了！其结构如下所示：typedefstructtreeNodestructtreeNode*childMAXCHILDREN;structtreeNode*sibling;intlineno;NodeKindnodeki

3、nd;unionStmtKindstmt;ExpKindexp;kind;unionTokenTypeop;intval;char*name;attr;ExpTypetype;/*fortypecheckingofexps*/TreeNode;3.UTIL.C/UTIL.H主要函数TreeNode*newStmtNode(StmtKindkind)此函数创建一个有关语法树的声明节点TreeNode*newExpNode(ExpKindkind)此函数创建一个有关语法树的表述节点char*copyString(char*s)此函数分配和创建一个新的已存在树的复制voidprintTree(Tre

4、eNode*tree)输出一个语法树这两个文件主要是关于语法树的创建和输出4.SCAN.c/SCAN.H主要有这么几个函数：staticintgetNextChar(void);staticvoidungetNextChar(void);staticTokenTypereservedLookup(char*s);TokenTypegetToken(void);reservedLookup函数是查找关键字的，在符号表中找。这里还定义了一个保存关键字的结构：staticstructchar*str;TokenTypetok;reservedWordsMAXRESERVED"if"

5、;,IF,"then",THEN,"else",ELSE,"end",END,"repeat",REPEAT,"until",UNTIL,"read",READ,"write",WRITE;最重要的是getToken(void)函数。这个相当于lex的功能，进行词法分析。也就是一个DFA，switch后面跟了一堆的case。其中getNextChar(void)函数的思路，以下列出：staticintgetNextChar(void)if(!(linepo

6、s<bufsize)lineno+;if(fgets(lineBuf,BUFLEN-1,source)if(EchoSource)fprintf(listing,"%4d:%s",lineno,lineBuf);bufsize=strlen(lineBuf);linepos=0;returnlineBuflinepos+;elseEOF_flag=TRUE;returnEOF;elsereturnlineBuflinepos+;4.PARSE.C/PARSE.H有这么几个函数：TreeNode*parse(void)staticTreeNode*stmt_sequen

7、ce(void);staticTreeNode*statement(void);staticTreeNode*if_stmt(void);staticTreeNode*repeat_stmt(void);staticTreeNode*assign_stmt(void);staticTreeNode*read_stmt(void);staticTreeNode*write_stmt(void);staticTreeNode*exp(void);staticTreeNode*simple_exp(void);staticTreeNode*term(void);staticTreeNode*fact

8、or(void);最重要的是parse这个函数，就是用来构造整个程序的语法树的。下面的一堆私有函数构造相应语法的语法树，然后parse最后把它们这些子树整合成一个大树。5.SYMTAB.C/SYMTAB.H这个是符号表操作的，也就是词法分析的时候查找表，看该token是不是关键字。如果不是，就当作表识符添加进去。在语法分析的时候也要用到，看变量有没有声明的时候用的。三、实验心得：通过这次实验，仔细地去查看和分析了TINY编译器的部分源码。了解到了编译器的运行：检查参数正确否(tiny.exefilename)->构造语法树(调用parse函数)->根据语法树生成代码(调用codeG

9、en函数)，同时熟悉了编译器是如何使用prase函数进行语法树的构建以及语法树生成代码的转化，最主要的是进一步清晰了解到编译器的构造和运行原理，加深了对课本知识的运用和拓展，感觉收获很大！Main.c/*/*/*/*/*/*File:main.c/*MainprogramforTINYcompiler/*CompilerConstruction:PrinciplesandPractice/*KennethC.Louden/*/#include "globals.h/* set NO_PARSE to TRUE to get a scanner-only compiler创建一个只扫描

10、的编译器*/#define NO_PARSE FALSE/* set NO_ANALYZE to TRUE to get a parser-only compiler时创建一个只分析和扫描的编译器*/#define NO_ANALYZE FALSENO_PARSE 为 true 时NO_ANALYZE 为 true/*setNO_CODEtoTRUEtogetacompilerthatdoesnot*generatecodeNO_CODE为true时创建一个执行语义分析，但不生成代码的编译器*/#include "util.h"#if NO_PARSE #include &

11、quot;scan.h" #else#include "parse.h" #if !NO_ANALYZE #include "analyze.h #if !NO_CODE #include "cgen.h" #endif#defineNO_CODEFALSE/如果NO_PARSE为true,调用头文件scan.h/否则调用头文件prase.h/如果NO_ANALYZE为true,调用头文件analyze.h/如果NO_CODE为true,调用头文件cgen.h#endif#endif/结束预处理语句符号/*allocateglobal

12、variables分配全局变量*/intlineno=0;FILE*source;/指针指向源代码文件地址FILE*listing;/指针指向显示分析过程的文件的地址FILE*code;/指针指向目标汇编代码文件的地址/*allocateandsettracingflags分配和设置跟踪标志*/intEchoSource=FALSE;intTraceScan=FALSE;intTraceParse=FALSE;intTraceAnalyze=FALSE;intTraceCode=FALSE;intError=FALSE;/跟踪标志全部初始化为falsemain(intargc,char*arg

13、v)TreeNode*syntaxTree;charpgm120;/*sourcecodefilename*/if(argc!=2)fprintf(stderr,"usage:%s<filename>n",argv0);exit(1);/如果argv不为2，打印显示信息并退出strcpy(pgm,argv1);/复制argv1地址以null为退出字符的存储器区块到另一个存储器区块品pgm内if(strchr(pgm,'.')=NULL)strcat(pgm,".tny");/把.tyn文件所指字符串添加到pgm结尾处并添加&#

14、39;0'。source=fopen(pgm,"r");/以只读的方式打开pgm文件，并将指向pgm文件的指针返回给sourceif(source=NULL)fprintf(stderr,"File%snotfoundn",pgm);exit(1);/如果源代码文件为空，打印显示信息并退出listing=stdout;/*sendlistingtoscreen清单发送到屏幕*/fprintf(listing,"nTINYCOMPILATION:%sn",pgm);/答应显示语句#ifNO_PARSEwhile(getToken

15、()!=ENDFILE);/如果输入流没有结束就继续进行循环，直至结束#elsesyntaxTree=parse();/调用prase()函数构造语法树if(TraceParse)fprintf(listing,"nSyntaxtree:n");printTree(syntaxTree);/如果语法分析追踪标志为TRUE且没有语法错误,则将生成的语法树输出到屏幕#if!NO_ANALYZEif(!Error)if(TraceAnalyze)fprintf(listing,"nBuildingSymbolTable.n");buildSymtab(synt

16、axTree);/输出含符号表信息的语法树if(TraceAnalyze)fprintf(listing,"nCheckingTypes.n");typeCheck(syntaxTree);/输出含类型检查的语法树if(TraceAnalyze)fprintf(listing,"nTypeCheckingFinishedn");/打印结束信息#if!NO_CODEif(!Error)char*codefile;intfnlen=strcspn(pgm,".");codefile=(char*)calloc(fnlen+4,sizeof

17、(char);strncpy(codefile,pgm,fnlen);strcat(codefile,".tm");/将源文件名，去掉扩展名，添加扩展名.tmcode=fopen(codefile,"w");/以只写的方式打开目标汇编代码文件，并返回地址给codez指针if(code=NULL)printf("Unabletoopen%sn",codefile);exit(1);/如果code指针为空，打印显示信息并退出codeGen(syntaxTree,codefile);/目标代码生成fclose(code);#endif#en

18、dif#endif/结束之前对应的条件编译fclose(source);/关闭源代码文件return0;GLOBALS.H/*/*File:globals.h*/*GlobaltypesandvarsforTINYcompiler*/*mustcomebeforeotherincludefiles*/*CompilerConstruction:PrinciplesandPractice*/*KennethC.Louden*/*/#ifndef_GLOBALS_H_#define_GLOBALS_H_/宏定义#include<stdio.h>#include<stdlib.h&

19、gt;#include<ctype.h>#include<string.h>/头文件引用#ifndefFALSE#defineFALSE0/定义FALSE为0#endif#ifndefTRUE#defineTRUE1/定义TRUE为1#endif/*MAXRESERVED=thenumberofreservedwords*/#defineMAXRESERVED8/定义了关键字个数8个typedefenum/*book-keepingtokens*/ENDFILE,ERROR,/*reservedwords*/IF,THEN,ELSE,END,REPEAT,UNTIL,R

20、EAD,WRITE,/*multicharactertokens*/ID,NUM,/*specialsymbols*/ASSIGN,EQ,LT,PLUS,MINUS,TIMES,OVER,LPAREN,RPAREN,SEMITokenType;/定义了关键字，运算符等内容的枚举值externFILE*source;/*sourcecodetextfileexternFILE*listing;/*listingoutputtextfile源代码地址*/显示分析过程的文件的地址*/目标汇编代码文件的地址 */externFILE*code;/*codetextfileforTMsimulatore

21、xternintlineno;/*sourcelinenumberforlisting*/*/*Syntaxtreeforparsing*/*/typedefenumStmtK,ExpKNodeKind;/定义了语句类型的枚举值，这个决定树的节点typedefenumIfK,RepeatK,AssignK,ReadK,WriteKStmtKind;typedefenumOpK,ConstK,IdKExpKind;/*ExpTypeisusedfortypechecking*/typedefenumVoid,Integer,BooleanExpType;/定义了变量类型#defineMAXCHI

22、LDREN3/定义了最大子节点typedefstructtreeNode/定义了树的节点structtreeNode*childMAXCHILDREN;structtreeNode*sibling;intlineno;NodeKindnodekind;unionStmtKindstmt;ExpKindexp;kind;unionTokenTypeop;intval;char*name;attr;ExpTypetype;/*fortypecheckingofexps*/TreeNode;/*Flags for tracing*/*/*/*EchoSource=TRUEcausesthesourc

23、eprogramto* beechoedtothelistingfilewithlinenumbers* duringparsing* /externintEchoSource;/*TraceScan=TRUEcausestokeninformationtobe* printedtothelistingfileaseachtokenis* recognizedbythescanner* /externintTraceScan;/*TraceParse=TRUEcausesthesyntaxtreetobe* printedtothelistingfileinlinearizedform* (u

24、singindentsforchildren)* /externintTraceParse;/*TraceAnalyze=TRUEcausessymboltableinserts* andlookupstobereportedtothelistingfile*/externintTraceAnalyze;/*TraceCode=TRUEcausescommentstobewritten* totheTMcodefileascodeisgenerated*/externintTraceCode;/*Error=TRUEpreventsfurtherpassesifanerroroccurs*/e

25、xternintError;#endifSCAN.C/*词法扫描程序*/#include"globals.h"#include"util.h"#include"scan.h"/*定义的状态*/typedefenumSTART,/*初始状态*/INASSIGN,/*进入到赋值状态*/INCOMMENT,/*进入到注释状态*/INNUM,/*进入到数字状态*/INID,/*进入到标志符状态*/DONE/*状态结束*/StateType;/*每当语法分析程序需要一个单词时,就调用该子程序,得到（类别码,单词的值）*/*语义标识符和保留字*/

26、chartokenStringMAXTOKENLEN+1;/*BUFLEN=源代码的输入缓冲长度*/#defineBUFLEN256staticcharlineBufBUFLEN;/*当前行*/staticintlinepos=0;/*在linebuf中的当前位置*/staticintbufsize=0;/*缓冲区的字符串当前大小*/staticintEOF_flag=FALSE;/*如果读入下一个字符出错，设置EOF_flag为假。*/*从linebuffer中读取下一个非空白字符，如果读完，则读入新行。*/staticintgetNextChar(void)if(!(linepos<

27、bufsize)lineno+;if(fgets(lineBuf,BUFLEN-1,source)if(EchoSource)fprintf(listing,"%4d:%s",lineno,lineBuf);bufsize=strlen(lineBuf);linepos=0;returnlineBuflinepos+;elseEOF_flag=TRUE;returnEOF;elsereturnlineBuflinepos+;/*如果读入下一个字符出错，在linebuf中回退一个字符。*/staticvoidungetNextChar(void)if(!EOF_flag)li

28、nepos-;/*保留字的查找表*/staticstructchar*str;TokenTypetok;reservedWordsMAXRESERVED="if",IF,"then",THEN,"else",ELSE,"end",END,"repeat",REPEAT,"until",UNTIL,"read",READ,"write",WRITE;/*标识符是否是保留字*/staticTokenTypereservedLookup(ch

29、ar*s)inti;for(i=0;i<MAXRESERVED;i+)if(!strcmp(s,reservedWordsi.str)returnreservedWordsi.tok;returnID;/*扫描仪的主要功能函数gettoken返回源文件中下一个标记*/TokenTypegetToken(void)/*存入tokenstring的位置*/inttokenStringIndex=0;/*保存当前要返回的token；*/TokenTypecurrentToken;当前状态StateTypestate=START;/*表示保存到tokenstring的flag*/intsave;

30、while(state!=DONE)intc=getNextChar();/*从输入buf中读入一个字符*/save=TRUE;switch(state)caseSTART:if(isdigit(c)state=INNUM;elseif(isalpha(c)/*判断字母*/state=INID;elseif(c=':')state=INASSIGN;elseif(c='')|(c='/t')|(c='/n')save=FALSE;elseif(c='')save=FALSE;state=INCOMMENT;else

31、state=DONE;switch(c)caseEOF:save=FALSE;currentToken=ENDFILE;break;case'=':currentToken=EQ;break;case'<':currentToken=LT;break;case'+':currentToken=PLUS;break;case'-':currentToken=MINUS;break;casecurrentToken=TIMES;break;case'/':currentToken=OVER;break;case&

32、#39;(':currentToken=LPAREN;break;case')':currentToken=RPAREN;break;case'':currentToken=SEMI;break;default:currentToken=ERROR;break;break;caseINCOMMENT:save=FALSE;if(c=EOF)state=DONE;currentToken=ENDFILE;elseif(c='')state=START;break;caseINASSIGN:state=DONE;if(c='='

33、;)currentToken=ASSIGN;else/*在输入中备份*/ungetNextChar();save=FALSE;currentToken=ERROR;break;caseINNUM:if(!isdigit(c)/*在输入中备份*/ungetNextChar();save=FALSE;state=DONE;currentToken=NUM;break;caseINID:if(!isalpha(c)/*在输入中备份*/ungetNextChar();save=FALSE;state=DONE;currentToken=ID;break;caseDONE:default:/*应该不会执

34、行*/fprintf(listing,"ScannerBug:state=%d/n",state);state=DONE;currentToken=ERROR;break;if(save)&&(tokenStringIndex<=MAXTOKENLEN)tokenStringtokenStringIndex+=(char)c;/*解析单词结束*/if(state=DONE)tokenStringtokenStringIndex='/0'if(currentToken=ID)currentToken=reservedLookup(toke

35、nString);if(TraceScan)fprintf(listing,"/t%d:",lineno);printToken(currentToken,tokenString);returncurrentToken;SCAN.H/*/*对于tiny编译器的扫描程序接口*/*/#ifndef_SCAN_H_#define_SCAN_H_/*maxtokenlen是token的最大大小*/#defineMAXTOKENLEN40/*tokenString数组保存每个token*/externchartokenStringMAXTOKENLEN+1;/*f函数getToken

36、返回源程序中的下一个token*/TokenTypegetToken(void);#endifUTIL.H/*/*/*File:util.h/*UtilityfunctionsfortheTINYcompiler*/*CompilerConstruction:PrinciplesandPractice*/*/*KennethC.Louden/*/#ifndef_UTIL_H_#define_UTIL_H_/*ProcedureprintTokenprintsatoken* anditslexemetothelistingfile* /voidprintToken(TokenType,const

37、char*);/*FunctionnewStmtNodecreatesanewstatement* nodeforsyntaxtreeconstruction* /TreeNode*newStmtNode(StmtKind);/*FunctionnewExpNodecreatesanewexpression* nodeforsyntaxtreeconstruction* /TreeNode*newExpNode(ExpKind);/*FunctioncopyStringallocatesandmakesanew* copyofanexistingstring* /char*copyString

38、(char*);/*procedureprintTreeprintsasyntaxtreetothe* listingfileusingindentationtoindicatesubtrees* /voidprintTree(TreeNode*);#endifUTIL.C/*/*/*File:util.c/*Utilityfunctionimplementation*/*fortheTINYcompiler*/*CompilerConstruction:PrinciplesandPractice*/*/*KennethC.Louden/*/#include"globals.h#in

39、clude"util.h"/*ProcedureprintTokenprintsatoken* anditslexemetothelistingfile此函数输出一个标号*/voidprintToken(TokenTypetoken,constchar*tokenString)/和一个词素switch(token)caseIF:caseTHEN:caseELSE:caseEND:caseREPEAT:caseUNTIL:caseREAD:caseWRITE:fprintf(listing,"reservedword:%sn",tokenString);b

40、reak;caseASSIGN:fprintf(listing,":=n");break;caseLT:fprintf(listing,"<n");break;caseEQ:fprintf(listing,"=n");break;caseLPAREN:fprintf(listing,"(n");break;caseRPAREN:fprintf(listing,")n");break;caseSEMI:fprintf(listing,"n");break;casePLUS

41、:fprintf(listing,"+n");break;caseMINUS:fprintf(listing,"-n");break;caseTIMES:fprintf(listing,"*n");break;caseOVER:fprintf(listing,"/n");break;caseENDFILE:fprintf(listing,"EOFn");break;caseNUM:fprintf(listing,"NUM,val=%sn",tokenString);break

42、;caseID:fprintf(listing,"ID,name=%sn",tokenString);break;caseERROR:fprintf(listing,"ERROR:%sn",tokenString);break;default:/*shouldneverhappen*/fprintf(listing,"Unknowntoken:%dn",token);/*FunctionnewStmtNodecreatesanewstatement* nodeforsyntaxtreeconstruction* /TreeNode*n

43、ewStmtNode(StmtKindkind)/此函数创建一个有关此法树的声明节点TreeNode*t=(TreeNode*)malloc(sizeof(TreeNode);inti;if(t=NULL)fprintf(listing,"Outofmemoryerroratline%dn",lineno);elsefor(i=0;i<MAXCHILDREN;i+)t->childi=NULL;t->sibling=NULL;t->nodekind=StmtK;t->kind.stmt=kind;t->lineno=lineno;retu

44、rnt;/*FunctionnewExpNodecreatesanewexpression*nodeforsyntaxtreeconstruction*/TreeNode*newExpNode(ExpKindkind)/此函数创建一个有关此法树的表述节点TreeNode*t=(TreeNode*)malloc(sizeof(TreeNode);inti;if(t=NULL)fprintf(listing,"Outofmemoryerroratline%dn",lineno);elsefor(i=0;i<MAXCHILDREN;i+)t->childi=NULL;

45、t->sibling=NULL;t->nodekind=ExpK;t->kind.exp=kind;t->lineno=lineno;t->type=Void;returnt;/*FunctioncopyStringallocatesandmakesanew*copyofanexistingstring*/char*copyString(char*s)/此函数分配和创建一个新的已存在树的复制intn;char*t;if(s=NULL)returnNULL;n=strlen(s)+1;t=malloc(n);if(t=NULL)fprintf(listing,"Outofmemoryerr