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https://github.com/lurkydismal/captcc

A tiny C compiler written purely in JavaScript.
https://github.com/lurkydismal/captcc

c11 c99 compiler javascript

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A tiny C compiler written purely in JavaScript.

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README 

        
--there-will-be-huge-rebuild-improvment-update, if I have time :(

contributions are accepted and appreciated.



# CaptCC



[![Codacy Badge](https://app.codacy.com/project/badge/Grade/4579f7698a554d1a937ba354e155b7c1)](https://app.codacy.com/gh/lurkydismal/CaptCC/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade)



A tiny Proof-of-Concept C compiler written purely in JavaScript.   

It's been a while that I learned JS and it has worked for me in many different scenarios.      

I actually learned JS while analyzing a piece of malware written in JS. Then I got really interested.      

I was always curious if I can write a compiler; a tiny one.  

The funny part was writing it in JS :D



Parts of this project is derived from James Kyle talk at EmberConf 2016 (https://www.youtube.com/watch?v=Tar4WgAfMr4).  

I appreciate his effort to make this concept fairly easy to understand.    

He made a Lisp Compiler converting Lisp syntax to JS.   

I want to convert C to ASM.   



###### The parts below are almost complete:



1. tokenizer.js   

2. parser.js   

3. traverser.js   

4. processor.js   



To be completed:   



5. verifier.js   

6. codeGenerator.js     



#### State of the project:



###### What can be compiled:



* Function Definitions

* Integer Variable Assignments

* Char variable Assignments (i.e. char my_name[] = "Arash")

* Increments (var++)

* Additions and Subtraction

* Global Variables

* Return Statement

* Ifs Only (not nested, not if/elseif/else) Limited Condition support currently

* Function Calls with integer arguments



###### What can be parsed into the AST:



* Every legit character in C syntax

* Everything is grouped and parsed in a meaningful way

* Current groupings are "GlobalStatements" and "Functions".

* Inside GlobalStatements, there are Macros (Only #include for now :p), global varibales and structs.



###### What's missing from the parser:



typedef, define, ..., a lot!



##### Usage in browser console (remember to replace the new-lines with the actual \n while copy pasting this):



    initGenerate(processor(transformer(parser(tokenizer("

    //some comment here :D

    int glob = 10;

    int jack = 36;



    void test_void(void){

        int a = 777;

        int b = a;

        b++;

        return;

    }



    int test_int_ret(int a, int b){

        a++;

        b++;

        char my_name[] = \"Arash\";

        return a;

    }



    int main(){

        char greet[] = \"hello\n\";

        int v = 1;

        int f = 8;



        v++;

        f++;



        int k = -4 - 3 + 5 - 7 - 8 + 2 - 32;



        int e = v;



        test(1,2);



        if(v == 2) {

            int y = 5;

            y++;

        }



        if(k == 35) {

            int p = 55 + 34;

        }



	return 1;

    }

    "

    )))))                   



##### Output:   

  .text  

  .globl	_test_void  



  _test_void:  

  push %rbp  

  mov %rsp,%rbp  

  push $666  

  mov 0(%rsp),%rax  

  push %rax  

  incl (%rsp)  

  add $16,%rsp  

  pop %rbp  

  ret  



  .globl	_test_int_ret  



  _test_int_ret:  

  push %rbp    

  mov %rsp,%rbp  

  push %rcx  

  push %rdx  

  incl 8(%rsp)  

  incl (%rsp)  

  mov 8(%rsp), %rax  

  add $16,%rsp  

  pop %rbp  

  ret  

  

  .globl	main



  main:  

  push %rbp  

  mov %rsp,%rbp  

  push $1  

  push $8  

  incl 8(%rsp)  

  incl (%rsp)  

  xor %rax,%rax  

  sub $4,%rax  

  sub $3,%rax  

  add $5,%rax  

  sub $7,%rax  

  sub $8,%rax  

  add $2,%rax  

  sub $32,%rax  

  push %rax  

  mov 16(%rsp),%rax  

  push %rax  

  cmp $2,24(%rsp)  

  jne _ifv2_after  

  push $5    

  incl (%rsp)  

  add $8,%rsp  



   _ifv2_after:  

    cmp $35,8(%rsp)  

    jne _ifk35_after  

    xor %rax,%rax  

    add $55,%rax  

    add $34,%rax   

    push %rax  

    add $8,%rsp  



  _ifk35_after:

    mov $1,%rax  

    add $32,%rsp  

    pop %rbp  

    ret  



  .data    

    .globl	_glob  

    _glob:  

      .long	10  



  .globl	_jack  

    _jack:  

      .long	36  



##### To test the compiler code:



1. Copy the output into a file, let's say compiler_test.s  

2. generate the binary using GCC  



        gcc compiler_test.s -o compiler_test  



3. Run the binary