Brainfuck Compiler

A brainfuck compiler written in C.

Usage

$ ./bfc --help
Usage: bfc [OPTION...] infile
BFC - A brainfuck compiler written in C. Goes directly to ASM

-o, --output=FILE          Output to FILE instead of default(infile.s)
-O, --disableOptimization  Disable optimization
-?, --help                 Give this help list
    --usage                Give a short usage message

You can use it to compile to assembly. This can then be assembled using gcc, and executed directly.

$ make
$ ./bfc -o hello.s examples/hello.b 
$ gcc -o hello hello.s
$ ./hello
Hello World!

Platforms

Targets x86_64 assembly on linux.

Limitations

The compiler uses a fixed-size array of 30,000 elements for the cells. This makes it not technically turing complete.

Optimizations

Peephole optimisations

Combining Instructions

We combine successive increments/decrements:

    Compile             Combine
+-++  =>   Increment  1   =>   Increment 2
           Increment -1
           Increment  1
           Increment  1

If increments/decrements cancel out, we remove them entirely.

   Compile             Combine
+-   =>   Increment  1    =>   # nothing!
          Increment -1

We combine pointer increments:

    Compile                   Combine
><>>  =>   PointerIncrement  1   =>   PointerIncrement 2
           PointerIncrement -1
           PointerIncrement  1
           PointerIncrement  1

We remove increments if there's a read immediately after:

            Combine
Increment 1   =>   Read
Read

We remove successive reads:

     Combine
Read   =>   Read
Read