This is mostly a proof-of-concept for taking a piece of Brainfuck code and using Zig comptime to convert it into a native code.
This works by loading a brainfuck program and passing it to a compiler function that generates a runner that can be called with pointer to the initialized byte table.
const bf = @import("brainfuck.zig");
pub fn main() !void {
var buffer = [_]u8{0} ** 30000;
const bf_runner = bf.compile_brainfuck(@embedFile("test/hanoi.b"));
_ = bf_runner.execute(&buffer);
}
You can find most of the implementation in src/brainfuck.zig. The other Zig files in src/ contain the main() functions for the various generated executables.
For comparison, and also as a first step to this I've also implemented a basic runtime parser and interpreter.
I recommend building for performance:
$ zig build -Doptimize=ReleaseFast
You can then run the generated binaries:
$ ls zig-out/bin/
brainfuck_interpreter hanoi hello mandel
brainfuck_interpreter is the runtime interpreter. You can run any brainfuck program with it:
$ zig-out/bin/brainfuck_interpreter src/test/hello.b
Hello World!
The others are the compiled versions that can be run directly:
$ zig-out/bin/hello
Hello World!
The resulting binaries are very fast. hanoi and obviously hello complete almost instantly. mandel takes a bit over 1.5 seconds.
$ time zig-out/bin/mandel >/dev/null
real 0m1.543s
user 0m1.535s
sys 0m0.009s
This is way faster than my interpreter at least:
$ time zig-out/bin/brainfuck_interpreter src/test/mandel.b >/dev/null
real 0m35.028s
user 0m35.002s
sys 0m0.015s
I also compared it to Brainfuck transpiled with brainfucc to C and compiled with GCC and -O3. The results seem very similar. hello and hanoi basically complete instantly and mandel takes slightly longer (although I could probably tweak compiler settings).
$ cd brainfucc/
$ ./build.sh
$ time ./mandel >/dev/null
real 0m1.701s
user 0m1.684s
sys 0m0.013s
One thing the brainfucc compiled binaries have over the Zig ones is that they're a lot smaller. (15-64KB vs ~1MB)
Compilation take quite some time. I also had to crank up the @setEvalBranchQuota() value quite a bit (not that I exactly know what it is).
All Zig code is either generated by zig init or written by me. It can be used and re-licensed under the terms of the MIT license.
The hello.b is from the Brainfuck Wikipedia article. hanoi.b has been written by Clifford Wolf. mandel.b has been written by Erik Bosman.
The brainfucc.c transpiler has been written by Cory Burgett.