minCC – A Minimal C Compiler

minCC is a lightweight C compiler designed to support a significant subset of the C language. Built from scratch in C using Flex/Bison and using the LLVM api to deepen understanding of compiler design, parsing, and code generation.

See it in action

Compile test raymarcher under test/

./minCC test/raymarcher.c -o test/raymarcher.ll
llc -relocation-model=pic test/raymarcher.ll -o test/raymarcher.s
clang test/raymarcher.s -o test/raymarcher -fPIE -lm
./test/raymarcher

Basic Raymarcher with Sphere SDF:

qkkkkkkkkkkqqqqqqwwS tttt1 FF|||(7    k bbUUUUUUUUUUUUUUUUUbb k    7(|||FF 1tttt Swwqqqqqqkkkkkkkkkk
kkkkkkkkkkkkkkqqqqwwS  FFFFFFFF||(   kPPP666  bbbbbbbbb  666PPPk   (||FFFFFFFF  Swwqqqqkkkkkkkkkkkkk
kkkkkkkkkkkkkkkqqqqwwS FFFFFFFFF||( qkPP6666666hhhhhhh6666666PPkq (||FFFFFFFFF Swwqqqqkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqwwS |FFFFFFF||(7 kkPP666666hhhhhhhhh666666PPkk 7(||FFFFFFF| Swwqqqkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqqww  ||FFF||||(  qkPP666666hhhhhhhhh666666PPkq  (||||FFF||  wwqqqqkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqqwS   (||||((7    kPPP666666hhhhhhh666666PPPk    7((||||(   Swqqqqkkkkkkkkkkkkkkk
qkkkkkkkkkkkkkkqqqqwwS ooen    ///** kkPP66666666hhh66666666PPkk **///    neoo Swwqqqqkkkkkkkkkkkkkk
qqqqkkkkkkkkkqqqqqwwS ZZZZoo  ////**c kkPPP666666666666666PPPkk c**////  ooZZZZ Swwqqqqqkkkkkkkkkqqq
qqqqqqqqqqqqqqqqqwwS 555ZZZooe ****cr  qkPPPP66666666666PPPPkq  rc**** eooZZZ555 Swwqqqqqqqqqqqqqqqq
wwwwqqqqqqqqqqwwwwS555555ZZZoo  ccr      kkPPPPPPPPPPPPPPPkk      rcc  ooZZZ555555Swwwwqqqqqqqqqqwww
 ESSwwwwwwwwwwSS 555555555ZZZoe   ::::   5  kkkPPPPPPPkkk  5   ::::   eoZZZ555555555 SSwwwwwwwwwwSSE
t  |         ZZZ5555555555ZZoonC{   '    Z5YYY         YYY5Z    '   {CnooZZ5555555555ZZZ         |
t FFFFF||| eooZZZ5555555ZZZZoe CC{        5               5        {CC eoZZZZ5555555ZZZooe |||FFFFF
 FFFFFFFF|| nooZZZZZZZZZZZooe }}CC{      HHHHHHmmmmmmmHHHHHH      {CC}} eooZZZZZZZZZZZoon ||FFFFFFFF
FFFFFFFFF||(   eooooZZooooe }}}}CC   HHHmmmmmmmmmmmmmmmmmmmmmHHH   CC}}}} eooooZZooooe   (||FFFFFFFF
|FFFFFFF||(7 //*    een  }}}}}}C  HHHmmmmmmmm88888888888mmmmmmmmHHH  C}}}}}}  nee    *// 7(||FFFFFFF
(||||||||(7 ////**c   {CCCCCCC  HHmmmmmm888888888888888888888mmmmmmHH  CCCCCCC{   c**//// 7(||||||||
   (((7    ******cr :    {{{  HHmmmmm888888888888888888888888888mmmmmHH  {{{    : rc******    7(((
   qqkkkqq    ccr  :::'      HHmmmm8888888888888888888888888888888mmmmHH      ':::  rcc    qqkkkqq
kkPPPPPPPPPPkkk             Hmmmmm88888888888RRRRRRRRRRR88888888888mmmmmH             kkkPPPPPPPPPPk
bPPP666666PPPPPPkk         Hmmmm8888888888RRRRRRRRRRRRRRRRR8888888888mmmmH         kkPPPPPP666666PPP
Ub666666666666PPPPkq 5555 HHmmm888888888RRRRRRRRRRRRRRRRRRRRR888888888mmmHH 5555 qkPPPP666666666666b
UU 6666666666666PPPkk YY HHmmmm88888888RRRRRRRRRRRRRRRRRRRRRRR88888888mmmmHH YY kkPPP6666666666666 U
UUb66hhhhh66666666PPkk Y HHmmm88888888RRRRRRRRRRRRRRRRRRRRRRRRR88888888mmmHH Y kkPP66666666hhhhh66bU
UUb hhhhhhhh666666PPPk   Hmmmm88888888RRRRRRRRRRRRRRRRRRRRRRRRR88888888mmmmH   kPPP666666hhhhhhhh bU
UUb hhhhhhhhh66666PPPk   Hmmmm8888888RRRRRRRRRRRRRRRRRRRRRRRRRRR8888888mmmmH   kPPP66666hhhhhhhhh bU
UUb hhhhhhhh666666PPPk   Hmmmm88888888RRRRRRRRRRRRRRRRRRRRRRRRR88888888mmmmH   kPPP666666hhhhhhhh bU
UUb66hhhhh66666666PPkk Y HHmmm88888888RRRRRRRRRRRRRRRRRRRRRRRRR88888888mmmHH Y kkPP66666666hhhhh66bU
UU 6666666666666PPPkk YY HHmmmm88888888RRRRRRRRRRRRRRRRRRRRRRR88888888mmmmHH YY kkPPP6666666666666 U
Ub666666666666PPPPkq 5555 HHmmm888888888RRRRRRRRRRRRRRRRRRRRR888888888mmmHH 5555 qkPPPP666666666666b
bPPP666666PPPPPPkk         Hmmmm8888888888RRRRRRRRRRRRRRRRR8888888888mmmmH         kkPPPPPP666666PPP
kkPPPPPPPPPPkkk             Hmmmmm88888888888RRRRRRRRRRR88888888888mmmmmH             kkkPPPPPPPPPPk
   qqkkkqq    ccr  :::'      HHmmmm8888888888888888888888888888888mmmmHH      ':::  rcc    qqkkkqq
   (((7    ******cr :    {{{  HHmmmmm888888888888888888888888888mmmmmHH  {{{    : rc******    7(((
(||||||||(7 ////**c   {CCCCCCC  HHmmmmmm888888888888888888888mmmmmmHH  CCCCCCC{   c**//// 7(||||||||
|FFFFFFF||(7 //*    een  }}}}}}C  HHHmmmmmmmm88888888888mmmmmmmmHHH  C}}}}}}  nee    *// 7(||FFFFFFF
FFFFFFFFF||(   eooooZZooooe }}}}CC   HHHmmmmmmmmmmmmmmmmmmmmmHHH   CC}}}} eooooZZooooe   (||FFFFFFFF
 FFFFFFFF|| nooZZZZZZZZZZZooe }}CC{      HHHHHHmmmmmmmHHHHHH      {CC}} eooZZZZZZZZZZZoon ||FFFFFFFF
t FFFFF||| eooZZZ5555555ZZZZoe CC{        5               5        {CC eoZZZZ5555555ZZZooe |||FFFFF
t  |         ZZZ5555555555ZZoonC{   '    Z5YYY         YYY5Z    '   {CnooZZ5555555555ZZZ         |
 ESSwwwwwwwwwwSS 555555555ZZZoe   ::::   5  kkkPPPPPPPkkk  5   ::::   eoZZZ555555555 SSwwwwwwwwwwSSE
wwwwqqqqqqqqqqwwwwS555555ZZZoo  ccr      kkPPPPPPPPPPPPPPPkk      rcc  ooZZZ555555Swwwwqqqqqqqqqqwww
qqqqqqqqqqqqqqqqqwwS 555ZZZooe ****cr  qkPPPP66666666666PPPPkq  rc**** eooZZZ555 Swwqqqqqqqqqqqqqqqq
qqqqkkkkkkkkkqqqqqwwS ZZZZoo  ////**c kkPPP666666666666666PPPkk c**////  ooZZZZ Swwqqqqqkkkkkkkkkqqq
qkkkkkkkkkkkkkkqqqqwwS ooen    ///** kkPP66666666hhh66666666PPkk **///    neoo Swwqqqqkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqqwS   (||||((7    kPPP666666hhhhhhh666666PPPk    7((||||(   Swqqqqkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqqww  ||FFF||||(  qkPP666666hhhhhhhhh666666PPkq  (||||FFF||  wwqqqqkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkqqqwwS |FFFFFFF||(7 kkPP666666hhhhhhhhh666666PPkk 7(||FFFFFFF| Swwqqqkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkqqqqwwS FFFFFFFFF||( qkPP6666666hhhhhhh6666666PPkq (||FFFFFFFFF Swwqqqqkkkkkkkkkkkkkk
kkkkkkkkkkkkkkqqqqwwS  FFFFFFFF||(   kPPP666  bbbbbbbbb  666PPPk   (||FFFFFFFF  Swwqqqqkkkkkkkkkkkkk

Features

Language Constructs

• Control Flow: if, else, while, for, return statements
• Functions: Declaration, definition, and invocation
• Variable Operations:
  • Declarations and assignments
  • Compound assignments: =, +=, -=, *=, /=
  • Increment (++) and decrement (--) operators
• Pointers:
  • Dereferencing and pointer arithmetic
  • Arbitrary pointer depth
  • Pass-by-reference semantics
• Types Supported:
  • Primitive types: int, bool, char, float, double, short, long
  • Strings as char* with escape sequences (\n, \t, \0)
• Type Coercion:
  • Implicit conversions
  • Variadic function promotion
• Operators:
  • Arithmatic operators: +, -, *, /, %
  • Comparison operators: ==, !=, <, >, <=, >=
  • Logical operators: &&, ||
• Scopes: Proper variable scoping and shadowing
• Error Handling: Descriptive error messages for easier debugging
• (UNDER CONSTRUCTION) Standard Library Integration: Supports native functions like printf

Compilation Details

• Input: C-like source code
• Output: LLVM Intermediate Representation (IR) for further compilation or execution

Installation

1. Clone the repository:

git clone https://github.com/johndoesstuff/minCC.git
cd minCC

2. Build the compiler:

make

This will generate the minCC executable in the project directory.

Usage

To compile a source file:

./minCC [-o output.ll] <input file>

This will produce an output.ll file containing the LLVM IR.

To compile the LLVM IR to an executable:

llc -relocation-model=pic output.ll -o output.s
clang output.s -o output -fPIE -lm

Then, run your program:

./output

Testing

To ensure the compiler is working properly test programs are provided under the test/ and can be found in unit_tests.c