acorrenson / mfc

My First Compiler

MFC

MFC stands for "My First Compiler". It is a little compiler for a language created by SolarLiner. It targets ARM.

Using it

Compiling MFC requires dune and the ocamlgraph package.

[1] Dependencies installation :

opam install dune ocamlgraph

[2] Compiling Mfc :

dune build

[3] Using Mfc :

./_build/default/bin/main.exe -i input.get -o output.s [-r]

Help can be displayed passing the -h flag.

./_build/default/bin/main.exe -h

Overview of the Gen language

The language Mfc compiles is minimalist. It manipulates only integers.

Variables declarations

var x

Variables affectation

x = 5

Note : As in old C standards, declarations and affectations should be separated.

Loops

while (x < 10) {
  ...
}

Conditionals

if (x < 10) {
  ...
} else {
  ...
}

Arithmetic

x = x + x
x = x - x
x = x * x

Structure of the compiler

MFC is designed in OCaml. For now, it's a 3 passes compiler :

1. Parsing (using our own functional parser)
2. Quad generation (intermediate "3 addresses" language)
3. Arm generation (Register allocation)

Ocaml modules are like follow :

• Mfc_ast : Module implementing the AST
• Mfc_parser : The parser
• Mfc_parsing : The parsing lib
• Mfc_reg_alloc : Algorithm(s) for register allocation
• Mfc_quad : Quad generation module
• Mfc_env : Environnement manipulation (symbol table etc)

Todo(s)

Even if MFC is working on small examples, there are possible improvements.

• Real intermediate language : in fact, our quad language is an abstraction over ARM. and is not generic at all.
• Ast verification : The AST is currently poorly verified
• Code optimization : Some simple optimizations could be implemented (DAGs to avoid recomputing arithmetic expressions for example).