Intermediate Code Generator for For Loop - Compiler Design - Yacc Program

Program:

// Lex file: im4.l

alpha [A-Za-z]
digit [0-9]

%%

[\t \n]
for             return FOR;
{digit}+    return NUM;
{alpha}({alpha}|{digit})* return ID;
"<="         return LE;
">="         return GE;
"=="         return EQ;
"!="          return NE;
"||"            return OR;
"&&"         return AND;
.                return yytext[0];

%%

// Yacc file: im4.y

%{
#include <stdio.h>
#include <stdlib.h>
%}
%token ID NUM FOR LE GE EQ NE OR AND
%right "="
%left OR AND
%left '>' '<' LE GE EQ NE
%left '+' '-'
%left '*' '/'
%right UMINUS
%left '!'

%%

S       : FOR '(' E ';'{lab1();} E {lab2();}';' E {lab3();}')' E';'{lab4(); exit(0);}
         ;
E       : V '='{push();} E{codegen_assign();}
         | E '+'{push();} E{codegen();}
         | E '-'{push();} E{codegen();}
         | E '*'{push();} E{codegen();}
         | E '/'{push();} E{codegen();}
         | '(' E ')'
         | '-'{push();} E{codegen_umin();} %prec UMINUS
         | V
         | NUM{push();}
         ;
V       : ID {push();}
         ;

%%

#include "lex.yy.c"
#include<ctype.h>
char st[100][10];
int label[20];
int top=0;
char i_[2]="0";
char temp[2]="t";

int lno=0,ltop=0;
int start=1;

main()
{
    printf("Enter the expression:\n");
    yyparse();
}

push()
{
   strcpy(st[++top],yytext);
}

codegen()
{
    strcpy(temp,"t");
    strcat(temp,i_);
    printf("%s = %s %s %s\n",temp,st[top-2],st[top-1],st[top]);
    top-=2;
    strcpy(st[top],temp);
    i_[0]++;
}

codegen_umin()
{
    strcpy(temp,"t");
    strcat(temp,i_);
    printf("%s = -%s\n",temp,st[top]);
    top--;
    strcpy(st[top],temp);
    i_[0]++;
}

codegen_assign()
{
    printf("%s = %s\n",st[top-2],st[top]);
    top-=2;
}
lab1()
{
    printf("L%d: \n",lno++);
}
lab2()
{
    strcpy(temp,"t");
    strcat(temp,i_);
    printf("%s = not %s\n",temp,st[top]);
    printf("if %s goto L%d\n",temp,lno);
    i_[0]++;
    label[++ltop]=lno;
    lno++;
    printf("goto L%d\n",lno);
    label[++ltop]=lno;
    printf("L%d: \n",++lno);
 }
lab3()
{
    int x;
    x=label[ltop--];
    printf("goto L%d \n",start);
    printf("L%d: \n",x);
   
}

lab4()
{
    int x;
    x=label[ltop--];
    printf("goto L%d \n",lno);   
    printf("L%d: \n",x);
}

Output:
nn@linuxmint ~ $ lex im4.l
nn@linuxmint ~ $ yacc im4.y
conflicts: 4 shift/reduce
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the expression:
for(i=0;i=b;i=i+1) a=a+b;
i = 0
L0:
i = b
t0 = not i
if t0 goto L1
goto L2
L3:
t1 = i + 1
i = t1
goto L0
L2:
t2 = a + b
a = t2
goto L3
L1:
nn@linuxmint ~ $

Intermediate Code Generator for Arithmetic Expression II (Advanced)- Yacc Program - Compiler Lab

Program:

// Lex file: imadv.l

ALPHA [A-Za-z]
DIGIT [0-9]

%%

{ALPHA}({ALPHA}|{DIGIT})*        return ID;
{DIGIT}+ {yylval=atoi(yytext);       return NUM;}
[\n\t]                                             yyterminate();
.                                                   return yytext[0];

%%


// Yacc file: imadv.y

%token ID NUM
%right '='
%left '+' '-'
%left '*' '/'
%left UMINUS
%%

S    :    ID{push();} '='{push();} E{codegen_assign();}
      ;
E    :    E '+'{push();} T{codegen();}
      |    E '-'{push();} T{codegen();}
      |    T
      ;
T    :    T '*'{push();} F{codegen();}
      |    T '/'{push();} F{codegen();}
      |    F
      ;
F    :    '(' E ')'
      |    '-'{push();} F{codegen_umin();} %prec UMINUS
      |    ID{push();}
      |    NUM{push();}
      ;

%%

#include "lex.yy.c"
#include<ctype.h>
#include<string.h>
char st[100][25];
int top=0,ptr=0;
int tint=0; int tintar[200];

main()
{
    printf("Enter the expression : ");
    yyparse();
}

push()
{
  strcpy(st[++top],yytext);
  ptr++;
}

codegen()
{
    printf("t%d = %s",tint,st[top-2]);
    printnum(2);
    printf(" %s %s",st[top-1],st[top]);
    printnum(0);
    printf("\n");
    top-=2;ptr-=2;
    strcpy(st[top],"t");
    tintar[ptr]=tint;
    tint++;
}

codegen_umin()
{
    printf("t%d = -%s\n",tint,st[top]);
    printnum(0);
    top--;ptr--;
    strcpy(st[top],"t");
    tintar[ptr]=tint;
    tint++;
}
codegen_assign()
{
    printf("%s = ",st[top-2]);
    printnum(2);
    printf("%s",st[top]);
    printnum(0);
    printf("\n");
    top-=2;ptr-=2;
}
printnum(int n)
{
    if( strcmp(st[top-n],"t")==0)
    {
         printf("%d",tintar[ptr-n]);
    }
}

Output:

nn@linuxmint ~ $ lex imadv.l
nn@linuxmint ~ $ yacc imadv.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the expression : a=b*c+d*c-c/5+2*8-5+5*5/8-8*9/8+8*7
t0 = b * c
t1 = d * c
t2 = t0 + t1
t3 = c / 5
t4 = t2 - t3
t5 = 2 * 8
t6 = t4 + t5
t7 = t6 - 5
t8 = 5 * 5
t9 = t8 / 8
t10 = t7 + t9
t11 = 8 * 9
t12 = t11 / 8
t13 = t10 - t12
t14 = 8 * 7
t15 = t13 + t14
a = t15
nn@linuxmint ~ $

Intermediate Code Generator for While - Yacc Program - Compiler Lab

Program:

(Lex Program: intwh.l)


ALPHA [A-Za-z]
DIGIT [0-9]
%%
while                return WHILE;
{ALPHA}({ALPHA}|{DIGIT})*    return ID;
{DIGIT}+             {yylval=atoi(yytext); return NUM;}
[ \t]                 ;
\n                yyterminate();
.                 return yytext[0];
%%


(Yacc Program: intwh.y) 


%token ID NUM WHILE
%right '='
%left '+' '-'
%left '*' '/'
%left UMINUS
%%

S : WHILE{lab1();} '(' E ')'{lab2();} E ';'{lab3();}
  ;
E :V '='{push();} E{codegen_assign();}
  | E '+'{push();} E{codegen();}
  | E '-'{push();} E{codegen();}
  | E '*'{push();} E{codegen();}
  | E '/'{push();} E{codegen();}
  | '(' E ')'
  | '-'{push();} E{codegen_umin();} %prec UMINUS
  | V
  | NUM{push();}
  ;
V : ID {push();}
  ;
%%

#include "lex.yy.c"
#include<ctype.h>
char st[100][10];
int top=0;
char i_[2]="0";
char temp[2]="t";

int lnum=1;
int start=1;
main()
 {
 printf("Enter the expression : ");
 yyparse();
 }



push()
 {
  strcpy(st[++top],yytext);
 }

codegen()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
  printf("%s = %s %s %s\n",temp,st[top-2],st[top-1],st[top]);
  top-=2;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_umin()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
 printf("%s = -%s\n",temp,st[top]);
 top--;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_assign()
 {
 printf("%s = %s\n",st[top-2],st[top]);
 top-=2;
 }



lab1()
{
printf("L%d: \n",lnum++);
}


lab2()
{
 strcpy(temp,"t");
 strcat(temp,i_);
 printf("%s = not %s\n",temp,st[top]);
 printf("if %s goto L%d\n",temp,lnum);
 i_[0]++;
 }

lab3()
{
printf("goto L%d \n",start);
printf("L%d: \n",lnum);
}



Output :
nn@linuxmint ~ $ lex intwh.l
nn@linuxmint ~ $ yacc intwh.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxm./a.out
Enter the expression : while(k=c/s)k=k*c+d;
L1:
t0 = c / s
k = t0
t1 = not k
if t1 goto L0
t2 = k * c
t3 = t2 + d
k = t3
goto L1
L0:
nn@linuxmint ~ $

Intermediate Code Generator for If then else - Yacc Program - Compiler Lab

Program :

(lex Program : intif.l)

ALPHA [A-Za-z]
DIGIT [0-9]
%%
if                 return IF;
then                 return THEN;
else                 return ELSE;
{ALPHA}({ALPHA}|{DIGIT})*    return ID;
{DIGIT}+             {yylval=atoi(yytext); return NUM;}
[ \t]                 ;
\n                yyterminate();
.                 return yytext[0];
%%

(Yacc Program : intif.y)

%token ID NUM IF THEN ELSE
%right '='
%left '+' '-'
%left '*' '/'
%left UMINUS
%%

S : IF '(' E ')'{lab1();} THEN E ';'{lab2();} ELSE E ';'{lab3();}
  ;
E :V '='{push();} E{codegen_assign();}
  | E '+'{push();} E{codegen();}
  | E '-'{push();} E{codegen();}
  | E '*'{push();} E{codegen();}
  | E '/'{push();} E{codegen();}
  | '(' E ')'
  | '-'{push();} E{codegen_umin();} %prec UMINUS
  | V
  | NUM{push();}
  ;
V : ID {push();}
  ;
%%

#include "lex.yy.c"
#include<ctype.h>
char st[100][10];
int top=0;
char i_[2]="0";
char temp[2]="t";

int label[20];
int lnum=0;
int ltop=0;

main()
 {
 printf("Enter the expression : ");
 yyparse();
 }

push()
 {
  strcpy(st[++top],yytext);
 }

codegen()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
  printf("%s = %s %s %s\n",temp,st[top-2],st[top-1],st[top]);
  top-=2;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_umin()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
 printf("%s = -%s\n",temp,st[top]);
 top--;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_assign()
 {
 printf("%s = %s\n",st[top-2],st[top]);
 top-=2;
 }

lab1()
{
 lnum++;
 strcpy(temp,"t");
 strcat(temp,i_);
 printf("%s = not %s\n",temp,st[top]);
 printf("if %s goto L%d\n",temp,lnum);
 i_[0]++;
 label[++ltop]=lnum;
}

lab2()
{
int x;
lnum++;
x=label[ltop--];
printf("goto L%d\n",lnum);
printf("L%d: \n",x);
label[++ltop]=lnum;
}

lab3()
{
int y;
y=label[ltop--];
printf("L%d: \n",y);
}

Output:

nn@linuxmint ~ $ lex intif.l
nn@linuxmint ~ $ yacc intif.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the expression : if(k+8) then k=18;else c=s;
t0 = k + 8
t1 = not t0
if t1 goto L1
k = 18
goto L2
L1:
c = s
L2:
nn@linuxmint ~ $

Intermediate Code Generator for Arithmetic Expression - Yacc Program - Compiler Lab

Program:

(Lex Program : intar.l)

ALPHA [A-Za-z]
DIGIT [0-9]
%%

{ALPHA}({ALPHA}|{DIGIT})* return ID;
{DIGIT}+ {yylval=atoi(yytext); return NUM;}
[\n\t] yyterminate();
. return yytext[0];
%%

(Yacc Program : intar.y)

%token ID NUM
%right '='
%left '+' '-'
%left '*' '/'
%left UMINUS
%%

S : ID{push();} '='{push();} E{codegen_assign();}
   ;
E : E '+'{push();} T{codegen();}
   | E '-'{push();} T{codegen();}
   | T
   ;
T : T '*'{push();} F{codegen();}
   | T '/'{push();} F{codegen();}
   | F
   ;
F : '(' E ')'
   | '-'{push();} F{codegen_umin();} %prec UMINUS
   | ID{push();}
   | NUM{push();}
   ;
%%

#include "lex.yy.c"
#include<ctype.h>
char st[100][10];
int top=0;
char i_[2]="0";
char temp[2]="t";

main()
 {
 printf("Enter the expression : ");
 yyparse();
 }

push()
{
  strcpy(st[++top],yytext);
 }

codegen()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
  printf("%s = %s %s %s\n",temp,st[top-2],st[top-1],st[top]);
  top-=2;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_umin()
 {
 strcpy(temp,"t");
 strcat(temp,i_);
 printf("%s = -%s\n",temp,st[top]);
 top--;
 strcpy(st[top],temp);
 i_[0]++;
 }

codegen_assign()
 {
 printf("%s = %s\n",st[top-2],st[top]);
 top-=2;
 }


Output:

nn@linuxmint ~ $ lex intar.l
nn@linuxmint ~ $ yacc intar.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the expression : a=(k+8)*(c-s)
t0 = k + 8
t1 = c - s
t2 = t0 * t1
a = t2
nn@linuxmint ~ $