internal/rosa: initial cross-compilation support

This successfully cross-compiles the toolchain. More work is needed to
support cross-compilation on all native helpers and existing packages.

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

1 files changed, 58 insertions, 27 deletions

diff --git a/cmd/mbf/main.go b/cmd/mbf/main.go
index dd5ee624..9c41e3ff 100644
--- a/cmd/mbf/main.go
+++ b/cmd/mbf/main.go
@@ -742,24 +742,39 @@ func main() {
 		)
 	}
 
-	c.NewCommand(
-		"all",
-		command.UsageInternal,
-		func([]string) error {
-			all := rosa.CollectAll()
-			a := make(pkg.Collect, len(all))
-			for i, h := range all {
-				_, a[i] = rosa.Load(h)
-			}
-			return cm.Do(func(cache *pkg.Cache) (err error) {
-				_, _, err = cache.Cure(&a)
-				if pkg.IsCollected(err) {
-					err = nil
+	{
+		var flagCross string
+		c.NewCommand(
+			"all",
+			command.UsageInternal,
+			func([]string) error {
+				s := &builtin
+				if flagCross != "" {
+					s = s.NewCross(flagCross)
+					if !s.HasStageEarly() {
+						return pkg.UnsupportedArchError(flagCross)
+					}
 				}
-				return
-			})
-		},
-	)
+
+				all := s.CollectAll()
+				a := make(pkg.Collect, len(all))
+				for i, h := range all {
+					_, a[i] = rosa.Load(h)
+				}
+				return cm.Do(func(cache *pkg.Cache) (err error) {
+					_, _, err = cache.Cure(&a)
+					if pkg.IsCollected(err) {
+						err = nil
+					}
+					return
+				})
+			},
+		).Flag(
+			&flagCross,
+			"cross", command.StringFlag(""),
+			"Target architecture (cross-compilation)",
+		)
+	}
 
 	{
 		var (
@@ -768,6 +783,7 @@ func main() {
 			flagExport  string
 			flagRemote  bool
 			flagNoReply bool
+			flagCross   string
 			flagFaults  bool
 			flagPop     bool
 			flagRebuild bool
@@ -793,6 +809,14 @@ func main() {
 					t -= 1
 				}
 
+				s := &builtin
+				if flagCross != "" {
+					s = s.NewCross(flagCross)
+					if !s.HasStageEarly() {
+						return pkg.UnsupportedArchError(flagCross)
+					}
+				}
+
 				if flagGentoo != "" {
 					var checksum pkg.Checksum
 					if len(flagChecksum) != 0 {
@@ -800,12 +824,12 @@ func main() {
 							return err
 						}
 					}
-					builtin.SetGentooStage3(flagGentoo, checksum)
+					s.SetGentooStage3(flagGentoo, checksum)
 
 					t -= 3 // magic number to discourage misuse
 				}
 
-				_, a := rosa.LoadAt(t, rosa.ArtifactH(unique.Make(args[0])))
+				_, a := s.New(t).Load(rosa.ArtifactH(unique.Make(args[0])))
 				if a == nil {
 					return fmt.Errorf("unknown artifact %q", args[0])
 				}
@@ -964,6 +988,10 @@ func main() {
 			"no-reply", command.BoolFlag(false),
 			"Do not receive a reply from the daemon",
 		).Flag(
+			&flagCross,
+			"cross", command.StringFlag(""),
+			"Target architecture (cross-compilation)",
+		).Flag(
 			&flagBoot,
 			"boot", command.BoolFlag(false),
 			"Build on the stage0 toolchain",
@@ -1111,20 +1139,23 @@ func main() {
 			"Remove identifiers not reachable by loaded packages",
 			func([]string) error {
 				return cm.Do(func(cache *pkg.Cache) error {
-					t := rosa.New().Std()
-					handles := t.CollectAll()
+					s := rosa.New()
+					s.DropCaches(runtime.GOARCH, s.Flags())
+					handles := s.Std().CollectAll()
 
-					flags := t.Flags()
-					a := t.Append(nil, handles...)
+					flags := s.Flags()
+					a := s.Std().Append(nil, handles...)
 					for arch := range rosa.Arches(nil) {
 						if arch == runtime.GOARCH {
 							continue
 						}
 
-						t.DropCaches(arch, rosa.OptSkipCheck)
-						a = t.Append(a, handles...)
-						t.DropCaches(arch, flags)
-						a = t.Append(a, handles...)
+						s.DropCaches(arch, rosa.OptSkipCheck)
+						a = s.Std().Append(a, handles...)
+						s.DropCaches(arch, flags)
+						a = s.Std().Append(a, handles...)
+						s.DropCaches(runtime.GOARCH, flags)
+						a = s.NewCross(arch).Std().Append(a, handles...)
 					}
 
 					ids, checksums, err := cache.Clean(