Graal and PseudoGo

goGraal.md

I was reviewing some documents on the graalvm and its truffle languages and it occured to me that one could write a go ast to LLVM IR emitter. Go has pretty good support for ast operations, thus it looked feasable at least. Obviously next thing I did was to check and see if someone had already done this. And yes.There is a project doing exactly that.

The support for the language is not all there yet and honestly I don't think this is the most sustainable approach but it was fun to play with it. I got some minimal go(tre) code running through graal's lli pretty fast

Ingredients

• Install GraalVM, and then set your PATH so that you get the GraalVM binaries
• llvm (brew install llvm)
• go install github.com/zegl/tre/cmd/tre

Steps

• Create a simple go program eg:

$> cat main.go
package main

import "external"

func fib(num int) int {
	if num < 2 {
		return num
	}

	return fib(num-2) + fib(num-1)
}

func main() {
	// fib = 5702887
	external.Printf("fib = %d\n", fib(34))
}

• Use tre to emmit llvm code and funnel the output into llvm's assembler. This outputs llvm bit code. I did a minor modification to the tre toolchain to output lli ir to the stdout.

 $>tre main.go | /usr/local/opt/llvm@6/bin/llvm-as -o out.bc

Now run it with graal's llvm's IR interpreter

$>lli out.bc
fib = 5702887

You just run go code compiled to LLVM IR in the (Graal)JVM!!