cc

The least optimized compiler you'll ever see.

Currently implemented features

• functions and function calls (Sysv ABI)
• variables and global variables
• forward declarations (functions and global variables)
• loops
  • break, continue
• conditionals
• binary operations
• unary operations (++, --, !, ~, -)
• postfix operations (++, --)

TODO:

• add good error messages
• add octal char, hex char, unicode code point escape codes in lexer
• add power of two optimization for mul, div, mod
• support lvalues not just being identifiers (pointers)
• add comma operator (have to make it lower precedence than =)
  • honestly almost never used
• move function redefinition & param count error checking out of parser
• missing features
  • void, float
  • pointers (arrays, strings)
    • https://en.cppreference.com/w/c/language/pointer
    • pointer type
    • take pointer to (&)
      • for now don't support taking pointer to func args, but later on mark variable as having been moved to stack and move
      • lea -4(%rbp)
      • lea foo(%rip)
    • dereference (*)
      • load ptr into register, use register as mem addr
• test break after nested for loop
• keep track of pointer depth (char **arr)

char + char = char no widening int + char = int widen rhs char + int = int widen lhs int + int = int no widening

char a = char b no widening int a = char b widen rhs char a = int b truncate lhs int a = int b no widening

https://norasandler.com/2017/11/29/Write-a-Compiler.html https://github.com/DoctorWkt/acwj

http://www.quut.com/c/ANSI-C-grammar-y-1999.html http://www.quut.com/c/ANSI-C-grammar-l-1999.html