cmd/mbf: toolchain 3-stage non-determinism check

This unfortunately fails right now. Requires further investigation.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -15,6 +15,7 @@ import (
 	"hakurei.app/container"
 	"hakurei.app/container/check"
 	"hakurei.app/internal/pkg"
+	"hakurei.app/internal/rosa"
 	"hakurei.app/message"
 )
 
@@ -104,6 +105,36 @@ func main() {
 		)
 	}
 
+	c.NewCommand(
+		"stage3",
+		"Check for toolchain 3-stage non-determinism",
+		func(args []string) (err error) {
+			_, _, _, stage2 := (rosa.Std - 1).NewLLVM()
+			_, _, _, stage3 := rosa.Std.NewLLVM()
+			var (
+				pathname *check.Absolute
+				checksum [2]pkg.Checksum
+			)
+
+			if pathname, checksum[0], err = cache.Cure(stage2); err != nil {
+				return err
+			}
+			log.Println("stage2:", pathname)
+			if pathname, checksum[1], err = cache.Cure(stage3); err != nil {
+				return err
+			}
+			log.Println("stage3:", pathname)
+
+			if checksum[0] != checksum[1] {
+				err = &pkg.ChecksumMismatchError{
+					Got:  checksum[0],
+					Want: checksum[1],
+				}
+			}
+			return
+		},
+	)
+
 	c.MustParse(os.Args[1:], func(err error) {
 		if cache != nil {
 			cache.Close()