NTU Compiler Technology Project 3

tags: NTU_CT NTU Compiler Techonology of Programming Language YACC Lex

[TOC]

Objective

• The main task for this project is to revise src/parser.y and generate parser file properly to compile test code in test folder.
• And then use Graphviz command to visualize the structure of these test code

How to run?

• Just use make to compile all files in /src. Though you’ll get a lots of warning shown as below, you can ignore them and obtain the target file parser.

    bison -v -d parser.y
    parser.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
    flex lexer.l
    gcc -g -c alloc.c
    gcc -g -c parser.tab.c
    parser.tab.c: In function ‘yyparse’:
    parser.tab.c:2565:7: warning: implicit declaration of function ‘yyerror’; did you mean ‘yyerrok’? [-Wimplicit-function-declaration]
           yyerror (YY_("syntax error"));
           ^~~~~~~
           yyerrok
    parser.y: At top level:
    parser.y:825:3: warning: data definition has no type or storage class
       yydebug = 1;
       ^~~~~~~
    parser.y:825:3: warning: type defaults to ‘int’ in declaration of ‘yydebug’ [-Wimplicit-int]
    parser.y:827:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
     main (argc, argv)
     ^~~~
    parser.y: In function ‘main’:
    parser.y:834:5: warning: implicit declaration of function ‘printGV’; did you mean ‘printf’? [-Wimplicit-function-declaration]
         printGV(prog, NULL);
         ^~~~~~~
         printf
    gcc -g -c functions.c
    gcc -g -o parser parser.tab.o alloc.o functions.o -lfl
  

• Use parser to compile all files in /test folder and you will get AST_Graph.gv in /test folder. /src

    ./parser ../test/control.c
    dot -Tpng -o ../test/control.png ../test/AST_Graph.gv
    ./parser ../test/decl.c
    dot -Tpng -o ../test/decl.png ../test/AST_Graph.gv
    ./parser ../test/expr.c
    dot -Tpng -o ../test/expr.png ../test/AST_Graph.gv
    ./parser ../test/func.c
    dot -Tpng -o ../test/func.png ../test/AST_Graph.gv
  

• Note that in parser.y, I set yydebug = 1 so that we can see the debug message from parser

    #ifdef YYDEBUG
        yydebug = 1;
    #endif
  

For TA

• I changed a little bit functions.c that will generate AST_Graph.gv at test/ folder.

  void printGV(AST_NODE *root, char* fileName)
  {
    if (fileName == NULL) {
        fileName = "../test/AST_Graph.gv";
    }
    ...
  }
  

Analysis

• You can see the relationship between structure map and test code by yourself.
• control.c

    int main()
    {
        int i;
        int p;
        int k, j;
        for (i=0; i<9; i=i+1) {
                /* empty */
        }
        for (i=0, p=4+4; i<9; i=i+1, p=i) {
            write("test");
        }
        for (;;) {
            /*empty*/
        }
        while (1) {
        }
        while (2) {
            write("haha");
            write("wow");
        }
        if (k == j) {
            write("first");
        }
        if (k == j) {
            write("first");
        } else if (j == k) {
            write("second");
        } else {
            write("third");
        }
    }
  

  

• decl.c

    typedef float GFLOAT;
    int main() {
        typedef int INT, INT2, INT3;
        typedef float FLOAT;
        typedef void VOID;
        typedef void VOID2, VOID3;
        INT f[3][3*3-(4+2)/2];
        FLOAT f2;
    }
  

  

• expr.c

    int fn1() {
        return 1;
    }
    float fn3() {
        return 1.0;
    }
    int fn4(int a, int b) {
        return 1;
    }
    int expr(int a, int b, int c, int d,
            float fa, float fb, float fc) {
        int i, j, k, l;
        float fi = 1.0, fj = 2.0, fk = 3.0, fl = 4.0;
  
        fi = 1.2*fi + -fj * (fl - fk * fn3());
        fi = -fn3() -(-(-(4)));
        fi = !fn3() -(!(!(4)));
        i = !fn1();
        i = 1 < 2;
        i = 1 > 2;
        i = 1 >= 2;
        i = 1 <= 2;
        i = 1 != 2;
        i = 1 == 2;
        i = fn4(1+3*4*fn4(2,3), 3);
        return 1;
    }
    int main() {
    }
  

  

• func.c

    int fn1() {
        int ABC = 5;
        return ABC+5;
    }
    void fn2() {
    }
    void fn3(int a, int b[3][4]) {
    }
    int main() {
        int b[4][4];
        fn1();
        fn2();
        fn3(2, b);
    }
  

  

Reference

Github example Simple intro of yacc & lex Simple intro of Graphviz A GUIDE TO LEX & YACC from TA 大推：以lex/yacc實作算式計算機