l2geth: add access lists to statedb

l2geth/core/state/journal.go

@@ -129,6 +129,15 @@ type (
 	touchChange struct {
 		account *common.Address
 	}
+
+	// Changes to the access list
+	accessListAddAccountChange struct {
+		address *common.Address
+	}
+	accessListAddSlotChange struct {
+		address *common.Address
+		slot    *common.Hash
+	}
 )
 
 func (ch createObjectChange) revert(s *StateDB) {
@@ -230,3 +239,28 @@ func (ch addPreimageChange) revert(s *StateDB) {
 func (ch addPreimageChange) dirtied() *common.Address {
 	return nil
 }
+
+func (ch accessListAddAccountChange) revert(s *StateDB) {
+	/*
+		One important invariant here, is that whenever a (addr, slot) is added, if the
+		addr is not already present, the add causes two journal entries:
+		- one for the address,
+		- one for the (address,slot)
+		Therefore, when unrolling the change, we can always blindly delete the
+		(addr) at this point, since no storage adds can remain when come upon
+		a single (addr) change.
+	*/
+	s.accessList.DeleteAddress(*ch.address)
+}
+
+func (ch accessListAddAccountChange) dirtied() *common.Address {
+	return nil
+}
+
+func (ch accessListAddSlotChange) revert(s *StateDB) {
+	s.accessList.DeleteSlot(*ch.address, *ch.slot)
+}
+
+func (ch accessListAddSlotChange) dirtied() *common.Address {
+	return nil
+}

l2geth/core/state/statedb.go

@@ -100,6 +100,9 @@ type StateDB struct {
 
 	preimages map[common.Hash][]byte
 
+	// Per-transaction access list
+	accessList *accessList
+
 	// Journal of state modifications. This is the backbone of
 	// Snapshot and RevertToSnapshot.
 	journal        *journal
@@ -132,6 +135,7 @@ func New(root common.Hash, db Database) (*StateDB, error) {
 		logs:                make(map[common.Hash][]*types.Log),
 		preimages:           make(map[common.Hash][]byte),
 		journal:             newJournal(),
+		accessList:          newAccessList(),
 	}, nil
 }
 
@@ -163,6 +167,7 @@ func (s *StateDB) Reset(root common.Hash) error {
 	s.logs = make(map[common.Hash][]*types.Log)
 	s.logSize = 0
 	s.preimages = make(map[common.Hash][]byte)
+	s.accessList = newAccessList()
 	s.clearJournalAndRefund()
 	return nil
 }
@@ -673,6 +678,13 @@ func (s *StateDB) Copy() *StateDB {
 	for hash, preimage := range s.preimages {
 		state.preimages[hash] = preimage
 	}
+	// Do we need to copy the access list? In practice: No. At the start of a
+	// transaction, the access list is empty. In practice, we only ever copy state
+	// _between_ transactions/blocks, never in the middle of a transaction.
+	// However, it doesn't cost us much to copy an empty list, so we do it anyway
+	// to not blow up if we ever decide copy it in the middle of a transaction
+	state.accessList = s.accessList.Copy()
+
 	return state
 }
 
@@ -764,6 +776,7 @@ func (s *StateDB) Prepare(thash, bhash common.Hash, ti int) {
 	s.thash = thash
 	s.bhash = bhash
 	s.txIndex = ti
+	s.accessList = newAccessList()
 }
 
 func (s *StateDB) clearJournalAndRefund() {
@@ -815,3 +828,63 @@ func (s *StateDB) Commit(deleteEmptyObjects bool) (common.Hash, error) {
 		return nil
 	})
 }
+
+// PrepareAccessList handles the preparatory steps for executing a state transition with
+// regards to both EIP-2929 and EIP-2930:
+//
+// - Add sender to access list (2929)
+// - Add destination to access list (2929)
+// - Add precompiles to access list (2929)
+// - Add the contents of the optional tx access list (2930)
+//
+// This method should only be called if Berlin/2929+2930 is applicable at the current number.
+func (s *StateDB) PrepareAccessList(sender common.Address, dst *common.Address, precompiles []common.Address, list types.AccessList) {
+	s.AddAddressToAccessList(sender)
+	if dst != nil {
+		s.AddAddressToAccessList(*dst)
+	}
+	for _, addr := range precompiles {
+		s.AddAddressToAccessList(addr)
+	}
+	for _, el := range list {
+		s.AddAddressToAccessList(el.Address)
+		for _, key := range el.StorageKeys {
+			s.AddSlotToAccessList(el.Address, key)
+		}
+	}
+}
+
+// AddAddressToAccessList adds the given address to the access list
+func (s *StateDB) AddAddressToAccessList(addr common.Address) {
+	if s.accessList.AddAddress(addr) {
+		s.journal.append(accessListAddAccountChange{&addr})
+	}
+}
+
+// AddSlotToAccessList adds the given (address, slot)-tuple to the access list
+func (s *StateDB) AddSlotToAccessList(addr common.Address, slot common.Hash) {
+	addrMod, slotMod := s.accessList.AddSlot(addr, slot)
+	if addrMod {
+		// In practice, this should not happen, since there is no way to enter the
+		// scope of 'address' without having the 'address' become already added
+		// to the access list (via call-variant, create, etc).
+		// Better safe than sorry, though
+		s.journal.append(accessListAddAccountChange{&addr})
+	}
+	if slotMod {
+		s.journal.append(accessListAddSlotChange{
+			address: &addr,
+			slot:    &slot,
+		})
+	}
+}
+
+// AddressInAccessList returns true if the given address is in the access list.
+func (s *StateDB) AddressInAccessList(addr common.Address) bool {
+	return s.accessList.ContainsAddress(addr)
+}
+
+// SlotInAccessList returns true if the given (address, slot)-tuple is in the access list.
+func (s *StateDB) SlotInAccessList(addr common.Address, slot common.Hash) (addressPresent bool, slotPresent bool) {
+	return s.accessList.Contains(addr, slot)
+}

l2geth/core/state/statedb_test.go

@@ -680,3 +680,177 @@ func TestDeleteCreateRevert(t *testing.T) {
 		t.Fatalf("self-destructed contract came alive")
 	}
 }
+
+func TestStateDBAccessList(t *testing.T) {
+	// Some helpers
+	addr := func(a string) common.Address {
+		return common.HexToAddress(a)
+	}
+	slot := func(a string) common.Hash {
+		return common.HexToHash(a)
+	}
+
+	memDb := rawdb.NewMemoryDatabase()
+	db := NewDatabase(memDb)
+	state, _ := New(common.Hash{}, db)
+	state.accessList = newAccessList()
+
+	verifyAddrs := func(astrings ...string) {
+		t.Helper()
+		// convert to common.Address form
+		var addresses []common.Address
+		var addressMap = make(map[common.Address]struct{})
+		for _, astring := range astrings {
+			address := addr(astring)
+			addresses = append(addresses, address)
+			addressMap[address] = struct{}{}
+		}
+		// Check that the given addresses are in the access list
+		for _, address := range addresses {
+			if !state.AddressInAccessList(address) {
+				t.Fatalf("expected %x to be in access list", address)
+			}
+		}
+		// Check that only the expected addresses are present in the acesslist
+		for address := range state.accessList.addresses {
+			if _, exist := addressMap[address]; !exist {
+				t.Fatalf("extra address %x in access list", address)
+			}
+		}
+	}
+	verifySlots := func(addrString string, slotStrings ...string) {
+		if !state.AddressInAccessList(addr(addrString)) {
+			t.Fatalf("scope missing address/slots %v", addrString)
+		}
+		var address = addr(addrString)
+		// convert to common.Hash form
+		var slots []common.Hash
+		var slotMap = make(map[common.Hash]struct{})
+		for _, slotString := range slotStrings {
+			s := slot(slotString)
+			slots = append(slots, s)
+			slotMap[s] = struct{}{}
+		}
+		// Check that the expected items are in the access list
+		for i, s := range slots {
+			if _, slotPresent := state.SlotInAccessList(address, s); !slotPresent {
+				t.Fatalf("input %d: scope missing slot %v (address %v)", i, s, addrString)
+			}
+		}
+		// Check that no extra elements are in the access list
+		index := state.accessList.addresses[address]
+		if index >= 0 {
+			stateSlots := state.accessList.slots[index]
+			for s := range stateSlots {
+				if _, slotPresent := slotMap[s]; !slotPresent {
+					t.Fatalf("scope has extra slot %v (address %v)", s, addrString)
+				}
+			}
+		}
+	}
+
+	state.AddAddressToAccessList(addr("aa"))          // 1
+	state.AddSlotToAccessList(addr("bb"), slot("01")) // 2,3
+	state.AddSlotToAccessList(addr("bb"), slot("02")) // 4
+	verifyAddrs("aa", "bb")
+	verifySlots("bb", "01", "02")
+
+	// Make a copy
+	stateCopy1 := state.Copy()
+	if exp, got := 4, state.journal.length(); exp != got {
+		t.Fatalf("journal length mismatch: have %d, want %d", got, exp)
+	}
+
+	// same again, should cause no journal entries
+	state.AddSlotToAccessList(addr("bb"), slot("01"))
+	state.AddSlotToAccessList(addr("bb"), slot("02"))
+	state.AddAddressToAccessList(addr("aa"))
+	if exp, got := 4, state.journal.length(); exp != got {
+		t.Fatalf("journal length mismatch: have %d, want %d", got, exp)
+	}
+	// some new ones
+	state.AddSlotToAccessList(addr("bb"), slot("03")) // 5
+	state.AddSlotToAccessList(addr("aa"), slot("01")) // 6
+	state.AddSlotToAccessList(addr("cc"), slot("01")) // 7,8
+	state.AddAddressToAccessList(addr("cc"))
+	if exp, got := 8, state.journal.length(); exp != got {
+		t.Fatalf("journal length mismatch: have %d, want %d", got, exp)
+	}
+
+	verifyAddrs("aa", "bb", "cc")
+	verifySlots("aa", "01")
+	verifySlots("bb", "01", "02", "03")
+	verifySlots("cc", "01")
+
+	// now start rolling back changes
+	state.journal.revert(state, 7)
+	if _, ok := state.SlotInAccessList(addr("cc"), slot("01")); ok {
+		t.Fatalf("slot present, expected missing")
+	}
+	verifyAddrs("aa", "bb", "cc")
+	verifySlots("aa", "01")
+	verifySlots("bb", "01", "02", "03")
+
+	state.journal.revert(state, 6)
+	if state.AddressInAccessList(addr("cc")) {
+		t.Fatalf("addr present, expected missing")
+	}
+	verifyAddrs("aa", "bb")
+	verifySlots("aa", "01")
+	verifySlots("bb", "01", "02", "03")
+
+	state.journal.revert(state, 5)
+	if _, ok := state.SlotInAccessList(addr("aa"), slot("01")); ok {
+		t.Fatalf("slot present, expected missing")
+	}
+	verifyAddrs("aa", "bb")
+	verifySlots("bb", "01", "02", "03")
+
+	state.journal.revert(state, 4)
+	if _, ok := state.SlotInAccessList(addr("bb"), slot("03")); ok {
+		t.Fatalf("slot present, expected missing")
+	}
+	verifyAddrs("aa", "bb")
+	verifySlots("bb", "01", "02")
+
+	state.journal.revert(state, 3)
+	if _, ok := state.SlotInAccessList(addr("bb"), slot("02")); ok {
+		t.Fatalf("slot present, expected missing")
+	}
+	verifyAddrs("aa", "bb")
+	verifySlots("bb", "01")
+
+	state.journal.revert(state, 2)
+	if _, ok := state.SlotInAccessList(addr("bb"), slot("01")); ok {
+		t.Fatalf("slot present, expected missing")
+	}
+	verifyAddrs("aa", "bb")
+
+	state.journal.revert(state, 1)
+	if state.AddressInAccessList(addr("bb")) {
+		t.Fatalf("addr present, expected missing")
+	}
+	verifyAddrs("aa")
+
+	state.journal.revert(state, 0)
+	if state.AddressInAccessList(addr("aa")) {
+		t.Fatalf("addr present, expected missing")
+	}
+	if got, exp := len(state.accessList.addresses), 0; got != exp {
+		t.Fatalf("expected empty, got %d", got)
+	}
+	if got, exp := len(state.accessList.slots), 0; got != exp {
+		t.Fatalf("expected empty, got %d", got)
+	}
+	// Check the copy
+	// Make a copy
+	state = stateCopy1
+	verifyAddrs("aa", "bb")
+	verifySlots("bb", "01", "02")
+	if got, exp := len(state.accessList.addresses), 2; got != exp {
+		t.Fatalf("expected empty, got %d", got)
+	}
+	if got, exp := len(state.accessList.slots), 1; got != exp {
+		t.Fatalf("expected empty, got %d", got)
+	}
+}

l2geth/core/vm/interface.go

@@ -57,6 +57,16 @@ type StateDB interface {
 	// is defined according to EIP161 (balance = nonce = code = 0).
 	Empty(common.Address) bool
 
+	PrepareAccessList(sender common.Address, dest *common.Address, precompiles []common.Address, txAccesses types.AccessList)
+	AddressInAccessList(addr common.Address) bool
+	SlotInAccessList(addr common.Address, slot common.Hash) (addressOk bool, slotOk bool)
+	// AddAddressToAccessList adds the given address to the access list. This operation is safe to perform
+	// even if the feature/fork is not active yet
+	AddAddressToAccessList(addr common.Address)
+	// AddSlotToAccessList adds the given (address,slot) to the access list. This operation is safe to perform
+	// even if the feature/fork is not active yet
+	AddSlotToAccessList(addr common.Address, slot common.Hash)
+
 	RevertToSnapshot(int)
 	Snapshot() int