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https://github.com/keyvank/30cc
30 C Compiler
https://github.com/keyvank/30cc
c compiler educational
Last synced: 3 days ago
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30 C Compiler
- Host: GitHub
- URL: https://github.com/keyvank/30cc
- Owner: keyvank
- Created: 2024-09-25T21:38:20.000Z (about 2 months ago)
- Default Branch: main
- Last Pushed: 2024-10-28T16:08:05.000Z (19 days ago)
- Last Synced: 2024-10-29T19:29:46.586Z (17 days ago)
- Topics: c, compiler, educational
- Language: C
- Homepage:
- Size: 219 KB
- Stars: 35
- Watchers: 1
- Forks: 3
- Open Issues: 15
-
Metadata Files:
- Readme: README.md
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README
# 30 C Compiler!
`30cc` (Pronounced as *CCC*, because in the Persian language, the number 30 is pronounced as C) is a toy C compiler written in C, with the goal of being able to compile itself 🤝 This is my first attempt in writing a self-hosting software! What is a self-hosting software?
- Imagine `30cc` gets strong enough to be able to compile itself.
- I will first compile `30cc` with `gcc` to get the `30cc` compiler's binary.
- I will then use the `gcc`-generated `30cc` binary file to compile the `30cc` again.
- I now have a `30cc`-compiled version of `30cc`, which I can use for further developing the compiler!
- I can forget about `gcc`, as if it never existed! Beautiful hah? `30cc` is now all alive by itself!
`30cc` emits x86-64 assembly as its output. The outputs are totally unoptimized, but that's fine, the project aims to be educational.
Currently, this is the most complicated code `30cc` is able to successfully parse and compile a simple implementation of a linked-list:
```c
void *malloc(int sz);
void printf(char *s, ...);
struct node
{
int val;
void *next;
};
struct linked_list
{
struct node *first;
};
struct linked_list *new_list()
{
struct linked_list *ret = (struct linked_list *)malloc(8);
return ret;
}
void add_val(struct linked_list *lst, int val)
{
struct node *new = (struct node *)malloc(16);
*((int *)(&new->next)) = new;
new->val = val;
if (lst->first)
{
struct node *curr = lst->first;
while (curr->next)
{
curr = (struct node *)curr->next;
}
curr->next = (void *)new;
}
else
{
lst->first = new;
}
}
int main()
{
struct linked_list *lst = new_list();
add_val(lst, 123);
add_val(lst, 432);
add_val(lst, 999);
add_val(lst, 873);
struct node *curr = lst->first;
while (curr)
{
printf("%u\n", curr->val);
curr = (struct node *)curr->next;
}
}
```
## Usage
- First build the compiler using `gcc` by running: `make`
- Compile to NASM x86-64 assembly: `./a.out INP_FILE.c --asm > out.asm`
- Assemble with NASM: `nasm -f elf64 out.asm -o out.o`
- Link with the C standard-library: `ld -dynamic-linker /lib64/ld-linux-x86-64.so.2 -lc -o out out.o`
- Run the output: `./out`
## Contribute
The missing parts are:
- [ ] `#include` macro.
- [ ] `#ifdef`, `#define` and `#ifndef` macros.
- [ ] Field-access in structs (The `.` and `->` operators)
- [ ] Type-checker
- [ ] Some binary expressions (`+=`, `-=`, `*=`)
- [ ] Unary expressions (`++`, `--`, `-`, `!`)
- [ ] Pointer-integer addition (Based on the type-size)