gbuoy/test/regalloc.spec.ts

import { expect } from "chai"

import { edgeConnects } from "../lib/data/graph"
import { Loc } from "../lib/ir/loc"
import type { SSA } from "../lib/ir/ssa"
import { allocateRegisters, interference, liveness } from "../lib/regalloc"
import { R8 } from "../lib/sm83/cpu"

describe("liveness", () => {
    it("computes liveness", () => {
        const x = [0, 1, 2].map(i => Loc.vari("x" + i))
        const y = [0, 1].map(i => Loc.vari("y" + i))

        const block: Array<SSA> = [
            { dest: x[0], source: 1 },
            { dest: x[1], source: x[0], op: "add", source1: x[0] },
            { dest: x[2], source: x[1], op: "add", source1: x[0] },
            { dest: y[0], source: x[0], op: "add", source1: x[1] },
            { dest: y[1], source: y[0], op: "add", source1: x[2] },
        ]

        const info = liveness(block)

        expect(info[0]).to.deep.equal(new Set())
        expect(info[1]).to.deep.equal(new Set([x[0]]))
        expect(info[2]).to.deep.equal(new Set([x[0], x[1]]))
        expect(info[3]).to.deep.equal(new Set([x[0], x[1], x[2]]))
        expect(info[4]).to.deep.equal(new Set([y[0], x[2]]))
    })
})

describe("interference", () => {
    it("computes interference", () => {
        const block: Array<SSA> = [
            { dest: Loc.vari("a"), source: 7 },
            { dest: Loc.vari("b"), source: 3 },
            { dest: Loc.vari("x"), source: Loc.vari("a") }
        ]

        const info = liveness(block)
        const g = interference(block, info)

        expect(edgeConnects(g, "a", "b")).to.be.true
    })
})

describe("allocateRegisters", () => {
    it("allocates registers", () => {
        const block: Array<SSA> = [
            { dest: Loc.vari("a"), source: 7 },
            { dest: Loc.vari("b"), source: 3 },
            { dest: Loc.vari("x"), source: Loc.vari("a") }
        ]

        const alloc = allocateRegisters(block, Object.values(R8))

        expect(alloc.a).to.equal("A")
        expect(alloc.b).to.equal("B")
        expect(alloc.x).to.equal("A")
    })
})