Implement nv16 migration according to FIP31 (#1583)

* actor manifest data structure and cbor marshaler/unmarshaler

* implement manifest.Load

* system actor v8 state

* implement nv16 migration

* make gen

* check manifest version when loading

* move system actor migration to its own file

* fix system actor state for tests

* update determinism check sum

* lint

* initialize system actor state to undefined

* fix migration tests

* lint

* fix migrated code cids so that state is checkable

* initialize system actor with empty state

* properly initialize system actor state in test vm

* make determinism-gen

* document builtina actors data type

* add comment about manifest data being in the blockstore

* kill space

* keep deferredCodeCids structure around

* make test nv16 specific

* normalize system actor state construction

* follow the pattern in testing vm construction

* fix lint

actors/builtin/manifest/manifest.go

@@ -0,0 +1,49 @@
+package manifest
+
+import (
+	"context"
+	"fmt"
+
+	adt8 "github.com/filecoin-project/specs-actors/v8/actors/util/adt"
+
+	"github.com/ipfs/go-cid"
+)
+
+type Manifest struct {
+	Version uint64 // this is really u32, but cbor-gen can't deal with it
+	Data    cid.Cid
+
+	entries map[string]cid.Cid
+}
+
+type ManifestEntry struct {
+	Name string
+	Code cid.Cid
+}
+
+type ManifestData struct {
+	Entries []ManifestEntry
+}
+
+func (m *Manifest) Load(ctx context.Context, store adt8.Store) error {
+	if m.Version != 1 {
+		return fmt.Errorf("unknown manifest version %d", m.Version)
+	}
+
+	data := ManifestData{}
+	if err := store.Get(ctx, m.Data, &data); err != nil {
+		return err
+	}
+
+	m.entries = make(map[string]cid.Cid)
+	for _, e := range data.Entries {
+		m.entries[e.Name] = e.Code
+	}
+
+	return nil
+}
+
+func (m *Manifest) Get(name string) (cid.Cid, bool) {
+	c, ok := m.entries[name]
+	return c, ok
+}

actors/builtin/system/system_actor.go

@@ -3,10 +3,12 @@ package system
 import (
 	"github.com/filecoin-project/go-state-types/abi"
 	"github.com/filecoin-project/go-state-types/cbor"
+	"github.com/filecoin-project/go-state-types/exitcode"
 	"github.com/ipfs/go-cid"
 
 	"github.com/filecoin-project/specs-actors/v8/actors/builtin"
 	"github.com/filecoin-project/specs-actors/v8/actors/runtime"
+	"github.com/filecoin-project/specs-actors/v8/actors/util/adt"
 )
 
 type Actor struct{}
@@ -33,9 +35,8 @@ var _ runtime.VMActor = Actor{}
 
 func (a Actor) Constructor(rt runtime.Runtime, _ *abi.EmptyValue) *abi.EmptyValue {
 	rt.ValidateImmediateCallerIs(builtin.SystemActorAddr)
-
-	rt.StateCreate(&State{})
+	st, err := ConstructState(adt.AsStore(rt))
+	builtin.RequireNoErr(rt, err, exitcode.ErrIllegalState, "failed to construct state")
+	rt.StateCreate(st)
 	return nil
 }
-
-type State struct{}

actors/builtin/system/system_actor_state.go

@@ -0,0 +1,24 @@
+package system
+
+import (
+	"context"
+
+	cid "github.com/ipfs/go-cid"
+	xerrors "golang.org/x/xerrors"
+
+	"github.com/filecoin-project/specs-actors/v8/actors/builtin/manifest"
+	"github.com/filecoin-project/specs-actors/v8/actors/util/adt"
+)
+
+type State struct {
+	BuiltinActors cid.Cid // ManifestData
+}
+
+func ConstructState(store adt.Store) (*State, error) {
+	empty, err := store.Put(context.TODO(), &manifest.ManifestData{})
+	if err != nil {
+		return nil, xerrors.Errorf("failed to create empty manifest: %w", err)
+	}
+
+	return &State{BuiltinActors: empty}, nil
+}