core/state: use journaling approach

core/state/journal.go

@@ -216,33 +216,15 @@ func (j *journal) length() int {
 	return len(j.entries)
 }
 
-// stateChangedBytes computes the state bytes created by the call frame
-// identified by snapshotId. Since subcalls always compute their results
-// before the parent (innermost-first), this only scans journal entries
-// between this snapshot and the next one — the frame's own entries.
-// Subcall results are summed from the cache and subtracted.
-//
-// The result is cached in stateBytesCharged[snapshotId] so the parent
-// frame can look it up instead of re-scanning.
-func (j *journal) stateChangedBytes(snapshotId int, stateObjects map[common.Address]*stateObject) int64 {
-	// TODO (MariusVanDerWijden): this is a bit slop-py needs to be cleaned up
-	// Resolve snapshot index.
-	idx := sort.Search(len(j.validRevisions), func(i int) bool {
-		return j.validRevisions[i].id >= snapshotId
-	})
-	if idx == len(j.validRevisions) || j.validRevisions[idx].id != snapshotId {
-		panic(fmt.Errorf("snapshot id %v not found for stateChangedBytes", snapshotId))
+// stateChangedBytes computes the state bytes created by the current (topmost)
+// call frame, walking only entries that belong directly to this frame and
+// skipping over closed child frame ranges.
+func (j *journal) stateChangedBytes(stateObjects map[common.Address]*stateObject) int64 {
+	if len(j.validRevisions) == 0 {
+		return 0
 	}
-	start := j.validRevisions[idx].journalIndex
+	rev := j.validRevisions[len(j.validRevisions)-1]
 
-	// Our range is [start, end) where end is the next revision's start,
-	// or the end of the journal if we're the last revision.
-	end := len(j.entries)
-	if idx+1 < len(j.validRevisions) {
-		end = j.validRevisions[idx+1].journalIndex
-	}
-
-	// Walk only our own entries.
 	type slotKey struct {
 		addr common.Address
 		key  common.Hash
@@ -255,8 +237,11 @@ func (j *journal) stateChangedBytes(snapshotId int, stateObjects map[common.Addr
 	created := make(map[common.Address]bool)
 	codeChanged := make(map[common.Address]bool)
 
-	for i := start; i < end; i++ {
-		switch e := j.entries[i].(type) {
+	// Walk only this frame's own entries, skipping closed child ranges.
+	// Add cached subcall costs from closedChildren.
+	var subcallBytes int64
+	visit := func(e journalEntry) {
+		switch e := e.(type) {
 		case createContractChange:
 			created[e.account] = true
 		case codeChange:
@@ -268,6 +253,18 @@ func (j *journal) stateChangedBytes(snapshotId int, stateObjects map[common.Addr
 			}
 		}
 	}
+	idx := rev.journalIndex
+	for _, child := range rev.closedChildren {
+		for ; idx < child.start; idx++ {
+			visit(j.entries[idx])
+		}
+		// Add the cached cost for this subcall.
+		subcallBytes += j.stateBytesCharged[child.start]
+		idx = child.end
+	}
+	for ; idx < len(j.entries); idx++ {
+		visit(j.entries[idx])
+	}
 
 	var totalBytes int64
 	for range created {
@@ -296,7 +293,7 @@ func (j *journal) stateChangedBytes(snapshotId int, stateObjects map[common.Addr
 		//   cleared in earlier frame, re-set here — no charge.
 		// - X → Y (non-zero to non-zero): no charge.
 		// - zero → zero: no change.
-		// - !prevZero && curZero && !origZero: pre-exising slot was
+		// - !prevZero && curZero && !origZero: pre-existing slot was
 		// cleared now, don't refund to not enable gas tokens.
 	}
 	for addr := range codeChanged {
@@ -306,8 +303,11 @@ func (j *journal) stateChangedBytes(snapshotId int, stateObjects map[common.Addr
 		}
 	}
 
-	// Cache our result so the parent can look it up.
-	j.stateBytesCharged[snapshotId] = totalBytes
+	// Add subcall costs to get the total for this frame (own + children).
+	totalBytes += subcallBytes
+
+	// Cache so the parent can look up this frame's total cost.
+	j.stateBytesCharged[rev.journalIndex] = totalBytes
 	return totalBytes
 }
 

core/state/statedb.go

@@ -772,11 +772,10 @@ const (
 	CostPerSlot    = 32
 )
 
-// StateChangedBytes computes the state bytes created since the given snapshot,
-// excluding bytes already charged by subcalls. See journal.stateChangedBytes
-// for the detailed accounting.
-func (s *StateDB) StateChangedBytes(snapshotId int) int64 {
-	return s.journal.stateChangedBytes(snapshotId, s.stateObjects)
+// StateChangedBytes computes the state bytes created by the current (topmost)
+// call frame, excluding entries from closed child frames.
+func (s *StateDB) StateChangedBytes() int64 {
+	return s.journal.stateChangedBytes(s.stateObjects)
 }
 
 type removedAccountWithBalance struct {

core/state/statedb_hooked.go

@@ -293,6 +293,6 @@ func (s *hookedStateDB) Finalise(deleteEmptyObjects bool) *bal.StateAccessList {
 	return s.inner.Finalise(deleteEmptyObjects)
 }
 
-func (s *hookedStateDB) StateChangedBytes(snapshotId int) int64 {
-	return s.inner.StateChangedBytes(snapshotId)
+func (s *hookedStateDB) StateChangedBytes() int64 {
+	return s.inner.StateChangedBytes()
 }

core/state_transition.go

@@ -598,10 +598,9 @@ func (st *stateTransition) execute() (*ExecutionResult, error) {
 		ret   []byte
 		vmerr error // vm errors do not effect consensus and are therefore not assigned to err
 	)
-	// EIP-8037: Take a snapshot for the outer call frame so we can compute
-	// state gas for state changes made at the transaction level (nonce,
-	// value transfer, authorizations, and contract creation overhead).
-	outerSnapshot := st.state.Snapshot()
+
+	// Take a snapshot for gas calculation
+	st.state.Snapshot()
 
 	var execGasUsed vm.GasUsed
 	if contractCreation {
@@ -634,7 +633,7 @@ func (st *stateTransition) execute() (*ExecutionResult, error) {
 	// EIP-8037: charge state gas for the outer call frame's own state changes.
 	if rules.IsAmsterdam {
 		if vmerr == nil {
-			outerBytes := st.state.StateChangedBytes(outerSnapshot)
+			outerBytes := st.state.StateChangedBytes()
 			st.gasRemaining.Charge(vm.GasCosts{StateGas: outerBytes * int64(st.evm.Context.CostPerStateByte)})
 		} else {
 			if execGasUsed.StateGas > 0 {

core/vm/evm.go

@@ -281,11 +281,6 @@ func (evm *EVM) Call(caller common.Address, addr common.Address, input []byte, g
 		}
 		evm.StateDB.CreateAccount(addr)
 	}
-	if evm.chainRules.IsAmsterdam {
-		// Compute state changed bytes for account creation.
-		evm.StateDB.StateChangedBytes(snapshot)
-	}
-	innerSnapshot := evm.StateDB.Snapshot()
 	// Perform the value transfer only in non-syscall mode.
 	// Calling this is required even for zero-value transfers,
 	// to ensure the state clearing mechanism is applied.
@@ -327,7 +322,7 @@ func (evm *EVM) Call(caller common.Address, addr common.Address, input []byte, g
 		evm.StateDB.CloseSnapshot(snapshot)
 		if evm.chainRules.IsAmsterdam {
 			// Charge state costs
-			bytesCharged := evm.StateDB.StateChangedBytes(innerSnapshot)
+			bytesCharged := evm.StateDB.StateChangedBytes()
 			stateGasCost := GasCosts{StateGas: bytesCharged * int64(evm.Context.CostPerStateByte)}
 			if !gas.CanAfford(stateGasCost) {
 				gas.Exhaust()
@@ -389,7 +384,7 @@ func (evm *EVM) CallCode(caller common.Address, addr common.Address, input []byt
 	} else {
 		evm.StateDB.CloseSnapshot(snapshot)
 		if evm.chainRules.IsAmsterdam {
-			bytesCharged := evm.StateDB.StateChangedBytes(snapshot)
+			bytesCharged := evm.StateDB.StateChangedBytes()
 			stateGasCost := GasCosts{StateGas: bytesCharged * int64(evm.Context.CostPerStateByte)}
 			if !gas.CanAfford(stateGasCost) {
 				gas.Exhaust()
@@ -444,7 +439,7 @@ func (evm *EVM) DelegateCall(originCaller common.Address, caller common.Address,
 	} else {
 		evm.StateDB.CloseSnapshot(snapshot)
 		if evm.chainRules.IsAmsterdam {
-			bytesCharged := evm.StateDB.StateChangedBytes(snapshot)
+			bytesCharged := evm.StateDB.StateChangedBytes()
 			stateGasCost := GasCosts{StateGas: bytesCharged * int64(evm.Context.CostPerStateByte)}
 			if !gas.CanAfford(stateGasCost) {
 				gas.Exhaust()
@@ -599,12 +594,6 @@ func (evm *EVM) create(caller common.Address, code []byte, gas GasBudget, value
 	}
 	evm.Context.Transfer(evm.StateDB, caller, address, value, &evm.chainRules)
 
-	if evm.chainRules.IsAmsterdam {
-		// Compute the state changed for the contract init.
-		evm.StateDB.StateChangedBytes(snapshot)
-	}
-	initSnapshot := evm.StateDB.Snapshot()
-
 	// Initialise a new contract and set the code that is to be used by the EVM.
 	// The contract is a scoped environment for this execution context only.
 	contract := NewContract(caller, address, value, gas, evm.jumpDests)
@@ -624,7 +613,7 @@ func (evm *EVM) create(caller common.Address, code []byte, gas GasBudget, value
 		evm.StateDB.CloseSnapshot(snapshot)
 		if evm.chainRules.IsAmsterdam {
 			// Charge initcode's state changes to the created contract's gas.
-			bytesCharged := evm.StateDB.StateChangedBytes(initSnapshot)
+			bytesCharged := evm.StateDB.StateChangedBytes()
 			stateGasCost := GasCosts{StateGas: bytesCharged * int64(evm.Context.CostPerStateByte)}
 			if !contract.Gas.CanAfford(stateGasCost) {
 				contract.Gas.Exhaust()

core/vm/interface.go

@@ -106,7 +106,7 @@ type StateDB interface {
 	// Finalise must be invoked at the end of a transaction
 	Finalise(bool) *bal.StateAccessList
 
-	// StateChangedBytes returns the number of state bytes created since the
-	// given snapshot. Used by EIP-8037 for state gas metering.
-	StateChangedBytes(snapshotId int) int64
+	// StateChangedBytes returns the number of state bytes created by the
+	// current call frame. Used by EIP-8037 for state gas metering.
+	StateChangedBytes() int64
 }