core, params: implement EIP-3529 (#22733)

* core, params: implement EIP-3529

* core/vm: add london instructionset

* core/vm: add method doc for EIP enabler
Co-authored-by: Péter Szilágyi <peterke@gmail.com>

core/blockchain_test.go

@@ -3102,7 +3102,8 @@ func TestEIP2718Transition(t *testing.T) {
 	block := chain.GetBlockByNumber(1)
 
 	// Expected gas is intrinsic + 2 * pc + hot load + cold load, since only one load is in the access list
-	expected := params.TxGas + params.TxAccessListAddressGas + params.TxAccessListStorageKeyGas + vm.GasQuickStep*2 + vm.WarmStorageReadCostEIP2929 + vm.ColdSloadCostEIP2929
+	expected := params.TxGas + params.TxAccessListAddressGas + params.TxAccessListStorageKeyGas +
+		vm.GasQuickStep*2 + params.WarmStorageReadCostEIP2929 + params.ColdSloadCostEIP2929
 	if block.GasUsed() != expected {
 		t.Fatalf("incorrect amount of gas spent: expected %d, got %d", expected, block.GasUsed())
 

core/state_transition.go

@@ -241,6 +241,7 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 	sender := vm.AccountRef(msg.From())
 	homestead := st.evm.ChainConfig().IsHomestead(st.evm.Context.BlockNumber)
 	istanbul := st.evm.ChainConfig().IsIstanbul(st.evm.Context.BlockNumber)
+	eip3529 := st.evm.ChainConfig().IsLondon(st.evm.Context.BlockNumber)
 	contractCreation := msg.To() == nil
 
 	// Check clauses 4-5, subtract intrinsic gas if everything is correct
@@ -273,7 +274,13 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 		st.state.SetNonce(msg.From(), st.state.GetNonce(sender.Address())+1)
 		ret, st.gas, vmerr = st.evm.Call(sender, st.to(), st.data, st.gas, st.value)
 	}
-	st.refundGas()
+	if !eip3529 {
+		// Before EIP-3529: refunds were capped to gasUsed / 2
+		st.refundGas(params.RefundQuotient)
+	} else {
+		// After EIP-3529: refunds are capped to gasUsed / 5
+		st.refundGas(params.RefundQuotientEIP3529)
+	}
 	st.state.AddBalance(st.evm.Context.Coinbase, new(big.Int).Mul(new(big.Int).SetUint64(st.gasUsed()), st.gasPrice))
 
 	return &ExecutionResult{
@@ -283,9 +290,9 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 	}, nil
 }
 
-func (st *StateTransition) refundGas() {
-	// Apply refund counter, capped to half of the used gas.
-	refund := st.gasUsed() / 2
+func (st *StateTransition) refundGas(refundQuotient uint64) {
+	// Apply refund counter, capped to a refund quotient
+	refund := st.gasUsed() / refundQuotient
 	if refund > st.state.GetRefund() {
 		refund = st.state.GetRefund()
 	}

core/vm/eips.go

@@ -25,6 +25,7 @@ import (
 )
 
 var activators = map[int]func(*JumpTable){
+	3529: enable3529,
 	2929: enable2929,
 	2200: enable2200,
 	1884: enable1884,
@@ -115,28 +116,28 @@ func enable2929(jt *JumpTable) {
 	jt[SLOAD].constantGas = 0
 	jt[SLOAD].dynamicGas = gasSLoadEIP2929
 
-	jt[EXTCODECOPY].constantGas = WarmStorageReadCostEIP2929
+	jt[EXTCODECOPY].constantGas = params.WarmStorageReadCostEIP2929
 	jt[EXTCODECOPY].dynamicGas = gasExtCodeCopyEIP2929
 
-	jt[EXTCODESIZE].constantGas = WarmStorageReadCostEIP2929
+	jt[EXTCODESIZE].constantGas = params.WarmStorageReadCostEIP2929
 	jt[EXTCODESIZE].dynamicGas = gasEip2929AccountCheck
 
-	jt[EXTCODEHASH].constantGas = WarmStorageReadCostEIP2929
+	jt[EXTCODEHASH].constantGas = params.WarmStorageReadCostEIP2929
 	jt[EXTCODEHASH].dynamicGas = gasEip2929AccountCheck
 
-	jt[BALANCE].constantGas = WarmStorageReadCostEIP2929
+	jt[BALANCE].constantGas = params.WarmStorageReadCostEIP2929
 	jt[BALANCE].dynamicGas = gasEip2929AccountCheck
 
-	jt[CALL].constantGas = WarmStorageReadCostEIP2929
+	jt[CALL].constantGas = params.WarmStorageReadCostEIP2929
 	jt[CALL].dynamicGas = gasCallEIP2929
 
-	jt[CALLCODE].constantGas = WarmStorageReadCostEIP2929
+	jt[CALLCODE].constantGas = params.WarmStorageReadCostEIP2929
 	jt[CALLCODE].dynamicGas = gasCallCodeEIP2929
 
-	jt[STATICCALL].constantGas = WarmStorageReadCostEIP2929
+	jt[STATICCALL].constantGas = params.WarmStorageReadCostEIP2929
 	jt[STATICCALL].dynamicGas = gasStaticCallEIP2929
 
-	jt[DELEGATECALL].constantGas = WarmStorageReadCostEIP2929
+	jt[DELEGATECALL].constantGas = params.WarmStorageReadCostEIP2929
 	jt[DELEGATECALL].dynamicGas = gasDelegateCallEIP2929
 
 	// This was previously part of the dynamic cost, but we're using it as a constantGas
@@ -144,3 +145,12 @@ func enable2929(jt *JumpTable) {
 	jt[SELFDESTRUCT].constantGas = params.SelfdestructGasEIP150
 	jt[SELFDESTRUCT].dynamicGas = gasSelfdestructEIP2929
 }
+
+// enable3529 enabled "EIP-3529: Reduction in refunds":
+// - Removes refunds for selfdestructs
+// - Reduces refunds for SSTORE
+// - Reduces max refunds to 20% gas
+func enable3529(jt *JumpTable) {
+	jt[SSTORE].dynamicGas = gasSStoreEIP3529
+	jt[SELFDESTRUCT].dynamicGas = gasSelfdestructEIP3529
+}

core/vm/interpreter.go

@@ -98,6 +98,8 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 	if cfg.JumpTable[STOP] == nil {
 		var jt JumpTable
 		switch {
+		case evm.chainRules.IsLondon:
+			jt = londonInstructionSet
 		case evm.chainRules.IsBerlin:
 			jt = berlinInstructionSet
 		case evm.chainRules.IsIstanbul:

core/vm/jump_table.go

@@ -57,11 +57,20 @@ var (
 	constantinopleInstructionSet   = newConstantinopleInstructionSet()
 	istanbulInstructionSet         = newIstanbulInstructionSet()
 	berlinInstructionSet           = newBerlinInstructionSet()
+	londonInstructionSet           = newLondonInstructionSet()
 )
 
 // JumpTable contains the EVM opcodes supported at a given fork.
 type JumpTable [256]*operation
 
+// newLondonInstructionSet returns the frontier, homestead, byzantium,
+// contantinople, istanbul, petersburg, berlin and london instructions.
+func newLondonInstructionSet() JumpTable {
+	instructionSet := newBerlinInstructionSet()
+	enable3529(&instructionSet) // EIP-3529: Reduction in refunds https://eips.ethereum.org/EIPS/eip-3529
+	return instructionSet
+}
+
 // newBerlinInstructionSet returns the frontier, homestead, byzantium,
 // contantinople, istanbul, petersburg and berlin instructions.
 func newBerlinInstructionSet() JumpTable {

params/protocol_params.go

@@ -57,6 +57,16 @@ const (
 	SstoreResetGasEIP2200             uint64 = 5000  // Once per SSTORE operation from clean non-zero to something else
 	SstoreClearsScheduleRefundEIP2200 uint64 = 15000 // Once per SSTORE operation for clearing an originally existing storage slot
 
+	ColdAccountAccessCostEIP2929 = uint64(2600) // COLD_ACCOUNT_ACCESS_COST
+	ColdSloadCostEIP2929         = uint64(2100) // COLD_SLOAD_COST
+	WarmStorageReadCostEIP2929   = uint64(100)  // WARM_STORAGE_READ_COST
+
+	// In EIP-2200: SstoreResetGas was 5000.
+	// In EIP-2929: SstoreResetGas was changed to '5000 - COLD_SLOAD_COST'.
+	// In EIP-3529: SSTORE_CLEARS_SCHEDULE is defined as SSTORE_RESET_GAS + ACCESS_LIST_STORAGE_KEY_COST
+	// Which becomes: 5000 - 2100 + 1900 = 4800
+	SstoreClearsScheduleRefundEIP3529 uint64 = SstoreResetGasEIP2200 - ColdSloadCostEIP2929 + TxAccessListStorageKeyGas
+
 	JumpdestGas   uint64 = 1     // Once per JUMPDEST operation.
 	EpochDuration uint64 = 30000 // Duration between proof-of-work epochs.
 
@@ -137,6 +147,11 @@ const (
 	Bls12381PairingPerPairGas uint64 = 23000  // Per-point pair gas price for BLS12-381 elliptic curve pairing check
 	Bls12381MapG1Gas          uint64 = 5500   // Gas price for BLS12-381 mapping field element to G1 operation
 	Bls12381MapG2Gas          uint64 = 110000 // Gas price for BLS12-381 mapping field element to G2 operation
+
+	// The Refund Quotient is the cap on how much of the used gas can be refunded. Before EIP-3529,
+	// up to half the consumed gas could be refunded. Redefined as 1/5th in EIP-3529
+	RefundQuotient        uint64 = 2
+	RefundQuotientEIP3529 uint64 = 5
 )
 
 // Gas discount table for BLS12-381 G1 and G2 multi exponentiation operations