use llir/llvm@v0.3.0-pre2 for code generation

[mewmew]

As an experiment, use the latest version of llir/llvm for code generation.

codegen test case output:

u@x1 ~/D/l/e/codegen> go test -v
=== RUN   TestBinaryFunction

define i32 @main() {
; <label>:0
	%1 = call i32 @add(i32 10, i32 10)
	ret i32 %1
}

define i32 @add(i32 %x, i32 %y) {
; <label>:0
	%1 = add i32 10, 10
	ret i32 %1
}

--- PASS: TestBinaryFunction (0.00s)
PASS
ok  	github.com/elz-lang/elz/codegen	0.001s

Updates #5.

P.S. the test case was also updated to include a ret instruction for the @main function.

[codecov-io]

Codecov Report

Merging #115 into llir will decrease coverage by 1.02%.
The diff coverage is 52.63%.

@@            Coverage Diff             @@
##             llir     #115      +/-   ##
==========================================
- Coverage   73.46%   72.44%   -1.03%     
==========================================
  Files           5        5              
  Lines         196      196              
==========================================
- Hits          144      142       -2     
- Misses         52       53       +1     
- Partials        0        1       +1

Impacted Files	Coverage Δ
codegen/codegen.go	60.86% <52.63%> (-2.18%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2899fbb...6d3a3e1. Read the comment docs.

[mewmew]

Note, this ret instruction was added in the PR.

[dannypsnl]

newFnBuilder := newFn.NewBlock("")

[mewmew]

newFnBuilder := newFn.NewBlock("")

Done.

[mewmew]

I made the update, but after thinking about it further, there is a benefit with having the basic block created explicitly (as was done in the original code). The reason is that you may want to update how the builder works, right now, it always uses SetInsertPointAtEnd by default.

In particular, I would imagine that the type Builder interface in builder.go would be replaced with a concrete builder implementation that allows for more flexible control over insertion points for instructions.

This is just a suggestion however, and you can update the code at that time, should the need arise.

Cheers,
Robin

[dannypsnl]

Thanks for the explanation, I'm also thinking why not use concrete type XD.