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package pass_test
import (
"reflect"
"testing"
"github.com/mmcloughlin/avo/build"
"github.com/mmcloughlin/avo/ir"
"github.com/mmcloughlin/avo/operand"
"github.com/mmcloughlin/avo/pass"
"github.com/mmcloughlin/avo/reg"
)
func TestPruneSelfMoves(t *testing.T) {
// Construct a function containing a self-move.
ctx := build.NewContext()
ctx.Function("add")
ctx.MOVQ(operand.U64(1), reg.RAX)
ctx.MOVQ(operand.U64(2), reg.RCX)
ctx.MOVQ(reg.RAX, reg.RAX) // self move
ctx.MOVQ(reg.RCX, reg.R8)
ctx.ADDQ(reg.R8, reg.RAX)
// Build the function without the pass and save the nodes.
fn := BuildFunction(t, ctx)
pre := append([]ir.Node{}, fn.Nodes...)
// Apply the pass.
if err := pass.PruneSelfMoves(fn); err != nil {
t.Fatal(err)
}
// Confirm the self-move was removed and everything else was untouched.
expect := []ir.Node{}
for i, n := range pre {
if i != 2 {
expect = append(expect, n)
}
}
if !reflect.DeepEqual(fn.Nodes, expect) {
t.Fatal("unexpected result from self-move pruning")
}
}
func TestPruneJumpToFollowingLabel(t *testing.T) {
// Construct a function containing a jump to following.
ctx := build.NewContext()
ctx.Function("add")
ctx.XORQ(reg.RAX, reg.RAX)
ctx.JMP(operand.LabelRef("next"))
ctx.Label("next")
ctx.XORQ(reg.RAX, reg.RAX)
// Build the function with the PruneJumpToFollowingLabel pass.
fn := BuildFunction(t, ctx, pass.PruneJumpToFollowingLabel)
// Confirm no JMP instruction remains.
for _, i := range fn.Instructions() {
if i.Opcode == "JMP" {
t.Fatal("JMP instruction not removed")
}
}
}
func TestPruneDanglingLabels(t *testing.T) {
// Construct a function containing an unreferenced label.
ctx := build.NewContext()
ctx.Function("add")
ctx.XORQ(reg.RAX, reg.RAX)
ctx.JMP(operand.LabelRef("referenced"))
ctx.XORQ(reg.RAX, reg.RAX)
ctx.Label("dangling")
ctx.XORQ(reg.RAX, reg.RAX)
ctx.Label("referenced")
ctx.XORQ(reg.RAX, reg.RAX)
// Build the function with the PruneDanglingLabels pass.
fn := BuildFunction(t, ctx, pass.PruneDanglingLabels)
// Confirm the only label remaining is "referenced".
expect := []ir.Label{"referenced"}
if !reflect.DeepEqual(expect, fn.Labels()) {
t.Fatal("expected dangling label to be removed")
}
}
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