core/vm: remove initial gas tracking

core/state_transition.go

@@ -242,11 +242,12 @@ func ApplyMessage(evm *vm.EVM, msg *Message, gp *GasPool) (*ExecutionResult, err
 //  5. Run Script section
 //  6. Derive new state root
 type stateTransition struct {
-	gp           *GasPool
+	gp            *GasPool
-	msg          *Message
+	msg           *Message
-	gasRemaining vm.GasBudget
+	initialBudget vm.GasBudget
-	state        vm.StateDB
+	gasRemaining  vm.GasBudget
-	evm          *vm.EVM
+	state         vm.StateDB
+	evm           *vm.EVM
 }
 
 // newStateTransition initialises and returns a new state transition object.
@@ -304,6 +305,7 @@ func (st *stateTransition) buyGas() error {
 		st.evm.Config.Tracer.OnGasChange(0, st.msg.GasLimit, tracing.GasChangeTxInitialBalance)
 	}
 	st.gasRemaining = vm.NewGasBudget(st.msg.GasLimit)
+	st.initialBudget = st.gasRemaining.Copy()
 
 	mgvalU256, _ := uint256.FromBig(mgval)
 	st.state.SubBalance(st.msg.From, mgvalU256, tracing.BalanceDecreaseGasBuy)
@@ -552,7 +554,7 @@ func (st *stateTransition) execute() (*ExecutionResult, error) {
 	// Return gas to the gas pool
 	if rules.IsAmsterdam {
 		// Refund is excluded for returning
-		err = st.gp.ReturnGas(st.gasRemaining.InitialGas-peakGasUsed, st.gasUsed())
+		err = st.gp.ReturnGas(st.initialBudget.RegularGas-peakGasUsed, st.gasUsed())
 	} else {
 		// Refund is included for returning
 		err = st.gp.ReturnGas(st.gasRemaining.RegularGas, st.gasUsed())
@@ -684,7 +686,7 @@ func (st *stateTransition) returnGas() {
 
 // gasUsed returns the amount of gas used up by the state transition.
 func (st *stateTransition) gasUsed() uint64 {
-	return st.gasRemaining.Used()
+	return st.gasRemaining.Used(st.initialBudget)
 }
 
 // blobGasUsed returns the amount of blob gas used by the message.

core/vm/gas_table_test.go

@@ -97,12 +97,12 @@ func TestEIP2200(t *testing.T) {
 			Transfer:    func(StateDB, common.Address, common.Address, *uint256.Int, *params.Rules) {},
 		}
 		evm := NewEVM(vmctx, statedb, params.AllEthashProtocolChanges, Config{ExtraEips: []int{2200}})
-
+		initialGas := NewGasBudget(tt.gaspool)
-		_, leftOver, err := evm.Call(common.Address{}, address, nil, NewGasBudget(tt.gaspool), new(uint256.Int))
+		_, leftOver, err := evm.Call(common.Address{}, address, nil, initialGas.Copy(), new(uint256.Int))
 		if !errors.Is(err, tt.failure) {
 			t.Errorf("test %d: failure mismatch: have %v, want %v", i, err, tt.failure)
 		}
-		if used := leftOver.Used(); used != tt.used {
+		if used := leftOver.Used(initialGas); used != tt.used {
 			t.Errorf("test %d: gas used mismatch: have %v, want %v", i, used, tt.used)
 		}
 		if refund := evm.StateDB.GetRefund(); refund != tt.refund {
@@ -157,11 +157,12 @@ func TestCreateGas(t *testing.T) {
 			}
 
 			evm := NewEVM(vmctx, statedb, chainConfig, config)
-			ret, leftOver, err := evm.Call(common.Address{}, address, nil, NewGasBudget(uint64(testGas)), new(uint256.Int))
+			initialGas := NewGasBudget(uint64(testGas))
+			ret, leftOver, err := evm.Call(common.Address{}, address, nil, initialGas.Copy(), new(uint256.Int))
 			if err != nil {
 				return false
 			}
-			gasUsed = leftOver.Used()
+			gasUsed = leftOver.Used(initialGas)
 			if len(ret) != 32 {
 				t.Fatalf("test %d: expected 32 bytes returned, have %d", i, len(ret))
 			}

core/vm/gascosts.go

@@ -43,17 +43,16 @@ func (g GasCosts) String() string {
 type GasBudget struct {
 	RegularGas uint64 // The leftover gas for execution and state gas usage
 	StateGas   uint64 // The state gas reservoir
-	InitialGas uint64 // records the starting allowance for usage tracking
 }
 
 // NewGasBudget creates a GasBudget with the given initial regular gas allowance.
 func NewGasBudget(gas uint64) GasBudget {
-	return GasBudget{RegularGas: gas, InitialGas: gas}
+	return GasBudget{RegularGas: gas}
 }
 
 // Used returns the amount of regular gas consumed so far.
-func (g GasBudget) Used() uint64 {
+func (g GasBudget) Used(initial GasBudget) uint64 {
-	return g.InitialGas - g.RegularGas
+	return initial.RegularGas - g.RegularGas
 }
 
 // Exhaust sets all remaining gas to zero, preserving the initial amount
@@ -63,6 +62,10 @@ func (g *GasBudget) Exhaust() {
 	g.StateGas = 0
 }
 
+func (g *GasBudget) Copy() GasBudget {
+	return GasBudget{RegularGas: g.RegularGas, StateGas: g.StateGas}
+}
+
 // String returns a visual representation of the gas budget vector.
 func (g GasBudget) String() string {
 	return fmt.Sprintf("<%v,%v>", g.RegularGas, g.StateGas)

tests/state_test.go

@@ -315,8 +315,10 @@ func runBenchmark(b *testing.B, t *StateTest) {
 				b.StartTimer()
 				start := time.Now()
 
+				initialGas := vm.NewGasBudget(msg.GasLimit)
+
 				// Execute the message.
-				_, leftOverGas, err := evm.Call(sender.Address(), *msg.To, msg.Data, vm.NewGasBudget(msg.GasLimit), uint256.MustFromBig(msg.Value))
+				_, leftOverGas, err := evm.Call(sender.Address(), *msg.To, msg.Data, initialGas.Copy(), uint256.MustFromBig(msg.Value))
 				if err != nil {
 					b.Error(err)
 					return
@@ -325,7 +327,7 @@ func runBenchmark(b *testing.B, t *StateTest) {
 				b.StopTimer()
 				elapsed += uint64(time.Since(start))
 				refund += state.StateDB.GetRefund()
-				gasUsed += leftOverGas.Used()
+				gasUsed += leftOverGas.Used(initialGas)
 
 				state.StateDB.RevertToSnapshot(snapshot)
 			}