250 lines
11 KiB
Go
250 lines
11 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"errors"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/params"
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)
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func makeGasSStoreFunc(clearingRefund uint64) gasFunc {
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return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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// If we fail the minimum gas availability invariant, fail (0)
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if contract.Gas <= params.SstoreSentryGasEIP2200 {
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return 0, errors.New("not enough gas for reentrancy sentry")
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}
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// Gas sentry honoured, do the actual gas calculation based on the stored value
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var (
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y, x = stack.Back(1), stack.peek()
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slot = common.Hash(x.Bytes32())
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current = evm.StateDB.GetState(contract.Address(), slot)
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cost = uint64(0)
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)
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// Check slot presence in the access list
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if addrPresent, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
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cost = params.ColdSloadCostEIP2929
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
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if !addrPresent {
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// Once we're done with YOLOv2 and schedule this for mainnet, might
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// be good to remove this panic here, which is just really a
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// canary to have during testing
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panic("impossible case: address was not present in access list during sstore op")
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}
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}
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value := common.Hash(y.Bytes32())
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if current == value { // noop (1)
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// EIP 2200 original clause:
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// return params.SloadGasEIP2200, nil
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return cost + params.WarmStorageReadCostEIP2929, nil // SLOAD_GAS
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}
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original := evm.StateDB.GetCommittedState(contract.Address(), x.Bytes32())
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if original == current {
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if original == (common.Hash{}) { // create slot (2.1.1)
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return cost + params.SstoreSetGasEIP2200, nil
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}
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if value == (common.Hash{}) { // delete slot (2.1.2b)
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evm.StateDB.AddRefund(clearingRefund)
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}
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// EIP-2200 original clause:
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// return params.SstoreResetGasEIP2200, nil // write existing slot (2.1.2)
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return cost + (params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929), nil // write existing slot (2.1.2)
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}
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if original != (common.Hash{}) {
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if current == (common.Hash{}) { // recreate slot (2.2.1.1)
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evm.StateDB.SubRefund(clearingRefund)
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} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
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evm.StateDB.AddRefund(clearingRefund)
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}
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}
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if original == value {
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if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
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// EIP 2200 Original clause:
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//evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.SloadGasEIP2200)
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evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.WarmStorageReadCostEIP2929)
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} else { // reset to original existing slot (2.2.2.2)
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// EIP 2200 Original clause:
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// evm.StateDB.AddRefund(params.SstoreResetGasEIP2200 - params.SloadGasEIP2200)
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// - SSTORE_RESET_GAS redefined as (5000 - COLD_SLOAD_COST)
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// - SLOAD_GAS redefined as WARM_STORAGE_READ_COST
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// Final: (5000 - COLD_SLOAD_COST) - WARM_STORAGE_READ_COST
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evm.StateDB.AddRefund((params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929) - params.WarmStorageReadCostEIP2929)
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}
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}
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// EIP-2200 original clause:
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//return params.SloadGasEIP2200, nil // dirty update (2.2)
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return cost + params.WarmStorageReadCostEIP2929, nil // dirty update (2.2)
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}
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}
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// gasSLoadEIP2929 calculates dynamic gas for SLOAD according to EIP-2929
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// For SLOAD, if the (address, storage_key) pair (where address is the address of the contract
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// whose storage is being read) is not yet in accessed_storage_keys,
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// charge 2100 gas and add the pair to accessed_storage_keys.
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// If the pair is already in accessed_storage_keys, charge 100 gas.
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func gasSLoadEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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loc := stack.peek()
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slot := common.Hash(loc.Bytes32())
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// Check slot presence in the access list
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if _, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
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// If the caller cannot afford the cost, this change will be rolled back
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// If he does afford it, we can skip checking the same thing later on, during execution
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evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
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return params.ColdSloadCostEIP2929, nil
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}
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return params.WarmStorageReadCostEIP2929, nil
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}
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// gasExtCodeCopyEIP2929 implements extcodecopy according to EIP-2929
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// EIP spec:
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// > If the target is not in accessed_addresses,
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// > charge COLD_ACCOUNT_ACCESS_COST gas, and add the address to accessed_addresses.
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// > Otherwise, charge WARM_STORAGE_READ_COST gas.
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func gasExtCodeCopyEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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// memory expansion first (dynamic part of pre-2929 implementation)
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gas, err := gasExtCodeCopy(evm, contract, stack, mem, memorySize)
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if err != nil {
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return 0, err
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}
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addr := common.Address(stack.peek().Bytes20())
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// Check slot presence in the access list
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if !evm.StateDB.AddressInAccessList(addr) {
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evm.StateDB.AddAddressToAccessList(addr)
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var overflow bool
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// We charge (cold-warm), since 'warm' is already charged as constantGas
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if gas, overflow = math.SafeAdd(gas, params.ColdAccountAccessCostEIP2929-params.WarmStorageReadCostEIP2929); overflow {
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return 0, ErrGasUintOverflow
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}
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return gas, nil
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}
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return gas, nil
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}
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// gasEip2929AccountCheck checks whether the first stack item (as address) is present in the access list.
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// If it is, this method returns '0', otherwise 'cold-warm' gas, presuming that the opcode using it
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// is also using 'warm' as constant factor.
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// This method is used by:
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// - extcodehash,
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// - extcodesize,
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// - (ext) balance
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func gasEip2929AccountCheck(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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addr := common.Address(stack.peek().Bytes20())
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// Check slot presence in the access list
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if !evm.StateDB.AddressInAccessList(addr) {
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddAddressToAccessList(addr)
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// The warm storage read cost is already charged as constantGas
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return params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929, nil
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}
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return 0, nil
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}
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func makeCallVariantGasCallEIP2929(oldCalculator gasFunc) gasFunc {
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return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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addr := common.Address(stack.Back(1).Bytes20())
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// Check slot presence in the access list
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warmAccess := evm.StateDB.AddressInAccessList(addr)
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// The WarmStorageReadCostEIP2929 (100) is already deducted in the form of a constant cost, so
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// the cost to charge for cold access, if any, is Cold - Warm
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coldCost := params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929
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if !warmAccess {
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evm.StateDB.AddAddressToAccessList(addr)
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// Charge the remaining difference here already, to correctly calculate available
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// gas for call
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if !contract.UseGas(coldCost) {
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return 0, ErrOutOfGas
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}
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}
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// Now call the old calculator, which takes into account
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// - create new account
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// - transfer value
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// - memory expansion
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// - 63/64ths rule
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gas, err := oldCalculator(evm, contract, stack, mem, memorySize)
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if warmAccess || err != nil {
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return gas, err
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}
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// In case of a cold access, we temporarily add the cold charge back, and also
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// add it to the returned gas. By adding it to the return, it will be charged
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// outside of this function, as part of the dynamic gas, and that will make it
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// also become correctly reported to tracers.
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contract.Gas += coldCost
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var overflow bool
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if gas, overflow = math.SafeAdd(gas, coldCost); overflow {
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return 0, ErrGasUintOverflow
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}
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return gas, nil
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}
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}
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var (
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gasCallEIP2929 = makeCallVariantGasCallEIP2929(gasCall)
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gasDelegateCallEIP2929 = makeCallVariantGasCallEIP2929(gasDelegateCall)
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gasStaticCallEIP2929 = makeCallVariantGasCallEIP2929(gasStaticCall)
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gasCallCodeEIP2929 = makeCallVariantGasCallEIP2929(gasCallCode)
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gasSelfdestructEIP2929 = makeSelfdestructGasFn(true)
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// gasSelfdestructEIP3529 implements the changes in EIP-3529 (no refunds)
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gasSelfdestructEIP3529 = makeSelfdestructGasFn(false)
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// gasSStoreEIP2929 implements gas cost for SSTORE according to EIP-2929
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//
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// When calling SSTORE, check if the (address, storage_key) pair is in accessed_storage_keys.
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// If it is not, charge an additional COLD_SLOAD_COST gas, and add the pair to accessed_storage_keys.
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// Additionally, modify the parameters defined in EIP 2200 as follows:
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//
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// Parameter Old value New value
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// SLOAD_GAS 800 = WARM_STORAGE_READ_COST
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// SSTORE_RESET_GAS 5000 5000 - COLD_SLOAD_COST
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//
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//The other parameters defined in EIP 2200 are unchanged.
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// see gasSStoreEIP2200(...) in core/vm/gas_table.go for more info about how EIP 2200 is specified
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gasSStoreEIP2929 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP2200)
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// gasSStoreEIP3529 implements gas cost for SSTORE according to EIP-3529
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// Replace `SSTORE_CLEARS_SCHEDULE` with `SSTORE_RESET_GAS + ACCESS_LIST_STORAGE_KEY_COST` (4,800)
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gasSStoreEIP3529 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP3529)
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)
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// makeSelfdestructGasFn can create the selfdestruct dynamic gas function for EIP-2929 and EIP-3529
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func makeSelfdestructGasFn(refundsEnabled bool) gasFunc {
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gasFunc := func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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var (
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gas uint64
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address = common.Address(stack.peek().Bytes20())
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)
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if !evm.StateDB.AddressInAccessList(address) {
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddAddressToAccessList(address)
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gas = params.ColdAccountAccessCostEIP2929
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}
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// if empty and transfers value
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if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
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gas += params.CreateBySelfdestructGas
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}
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if refundsEnabled && !evm.StateDB.HasSelfDestructed(contract.Address()) {
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evm.StateDB.AddRefund(params.SelfdestructRefundGas)
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}
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return gas, nil
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}
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return gasFunc
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}
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