mimicc: MItyu's MIni C Compiler

A toy, self-hosted (subset of) C Compiler for Linux on x86_64.

Supported functionalities

Type

• char
• int
• Array
• Pointer (including function pointer)
• Struct
• Enum
• Typedef

Function

• Global function
• static attribute
• extern attribute
• Function call with over 6 arguments
• Variadic argument
  • va_start and va_end is available. (va_arg is not supported yet.)

Note that passing/returning struct itself is not supported.

Variable

• Global variable
• Local variable
• static attribute
• extern attribute
• Variable initializer (primitive types, structs, arrays)
• Type checking (incomplete)
  • So sometimes mimicc accepts incorrect C program and rejects correct C program.

Literals

• Decimal, hexadecimal, octal number
• Characters
• String literals
• Escape sequence
  • \', \", \\, \?, \a, \b, \f, \n, \r, \t, \v, and \0

Control syntax

• if, else if and else
• for (with variable declaration at initializer statement support: for (int i = 0; ...))
• while
• switch, case and default
• break
• continue
• return

Statements

• Compound literal for struct (it for array is not yet)
• Type cast
• One-line comment (// ...)
• Multi-line comment (/* ... */)

operators

• ==, !=, <, >, <=, >=, &&, and ||
• +=, *=, /=, %=, &=, |=, ^=, <<=, and >>=
• ++ and -- of both prefix and postfix
• +, *, /, and %
• &, |, ^, <<, and >> (Bit operation)
• ! ("not" operator)
• Addressing &
• Dereferencing *
• Unary + and - (e.g. +3 and -5)
• sizeof
• . and ->
• () (function call)
• [] (array accessing)
• Ternary operator (condition ? expr-true : expr-false)
• , (expr, expr, expr, ...)

Preprocess

• #include <header> and #include "header"
• #if, #elif, #end, and #ifdef
  • Nesting them is also OK.
• Macros
  • Object-like macro (e.g. #define BUFSIZE (64))
  • Function-like macro (e.g. #define SIZEOF(ar) (sizeof(ar) / sizeof(ar[0])))
  • #undef
  • Note that mimicc doesn't have infinite macro expansion guard, so mimicc won't return with recursive macro like this:

#define REC REC

#define MUTUAL_REC1(arg) MUTUAL_REC2(arg)
#define MUTUAL_REC2(arg) MUTUAL_REC1(arg)

Build menus

# Build mimicc compiler with gcc. The binary will available at ./mimicc.
$ make

# Build 2nd gen mimicc compiler.  The binary will available at ./test/self/mimicc.
$ make self

# Build 3rd gen mimicc compiler.  The binary will available at ./test/selfself/mimicc.
$ make selfself

Test menus

# Run tests for 1st gen mimicc compiler.
$ make test

# Run tests for 2nd gen mimicc compiler.
$ make test_self  or  $ make self_test

# Run tests for 3rd gen mimicc compiler.  Also check there's no differencies
# between assembly of 2nd gen mimicc and of 3rd gen mimicc.
$ make test_selfself or  $ make selfself_test

# Run all tests at once
$ make test_all

Compile your C program

$ cd path/to/this/repo
$ ./mimicc -o <out-asm-path> <in-c-program-path>
$ gcc -o <out-binary-path> <out-asm-path>

Acknowledgements

This project is heavily, heavily inspired by this web book. Great thanks:

• 「低レイヤを知りたい人のためのCコンパイラ作成入門」(https://www.sigbus.info/compilerbook)