plugeth/core/vm/operations_acl.go
Martin Holst Swende 65a1c2d829
core/vm: make gas cost reporting to tracers correct (#22702)
Previously, the makeCallVariantGasCallEIP2929 charged the cold account access cost directly, leading to an incorrect gas cost passed to the tracer from the main execution loop.
This change still temporarily charges the cost (to allow for an accurate calculation of the available gas for the call), but then afterwards refunds it and instead returns the correct total gas cost to be then properly charged in the main loop.
2021-04-27 13:21:41 +02:00

237 lines
10 KiB
Go

// Copyright 2020 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package vm
import (
"errors"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/params"
)
const (
ColdAccountAccessCostEIP2929 = uint64(2600) // COLD_ACCOUNT_ACCESS_COST
ColdSloadCostEIP2929 = uint64(2100) // COLD_SLOAD_COST
WarmStorageReadCostEIP2929 = uint64(100) // WARM_STORAGE_READ_COST
)
// gasSStoreEIP2929 implements gas cost for SSTORE according to EIP-2929"
//
// When calling SSTORE, check if the (address, storage_key) pair is in accessed_storage_keys.
// If it is not, charge an additional COLD_SLOAD_COST gas, and add the pair to accessed_storage_keys.
// Additionally, modify the parameters defined in EIP 2200 as follows:
//
// Parameter Old value New value
// SLOAD_GAS 800 = WARM_STORAGE_READ_COST
// SSTORE_RESET_GAS 5000 5000 - COLD_SLOAD_COST
//
//The other parameters defined in EIP 2200 are unchanged.
// see gasSStoreEIP2200(...) in core/vm/gas_table.go for more info about how EIP 2200 is specified
func gasSStoreEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
// If we fail the minimum gas availability invariant, fail (0)
if contract.Gas <= params.SstoreSentryGasEIP2200 {
return 0, errors.New("not enough gas for reentrancy sentry")
}
// Gas sentry honoured, do the actual gas calculation based on the stored value
var (
y, x = stack.Back(1), stack.peek()
slot = common.Hash(x.Bytes32())
current = evm.StateDB.GetState(contract.Address(), slot)
cost = uint64(0)
)
// Check slot presence in the access list
if addrPresent, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
cost = ColdSloadCostEIP2929
// If the caller cannot afford the cost, this change will be rolled back
evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
if !addrPresent {
// Once we're done with YOLOv2 and schedule this for mainnet, might
// be good to remove this panic here, which is just really a
// canary to have during testing
panic("impossible case: address was not present in access list during sstore op")
}
}
value := common.Hash(y.Bytes32())
if current == value { // noop (1)
// EIP 2200 original clause:
// return params.SloadGasEIP2200, nil
return cost + WarmStorageReadCostEIP2929, nil // SLOAD_GAS
}
original := evm.StateDB.GetCommittedState(contract.Address(), x.Bytes32())
if original == current {
if original == (common.Hash{}) { // create slot (2.1.1)
return cost + params.SstoreSetGasEIP2200, nil
}
if value == (common.Hash{}) { // delete slot (2.1.2b)
evm.StateDB.AddRefund(params.SstoreClearsScheduleRefundEIP2200)
}
// EIP-2200 original clause:
// return params.SstoreResetGasEIP2200, nil // write existing slot (2.1.2)
return cost + (params.SstoreResetGasEIP2200 - ColdSloadCostEIP2929), nil // write existing slot (2.1.2)
}
if original != (common.Hash{}) {
if current == (common.Hash{}) { // recreate slot (2.2.1.1)
evm.StateDB.SubRefund(params.SstoreClearsScheduleRefundEIP2200)
} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
evm.StateDB.AddRefund(params.SstoreClearsScheduleRefundEIP2200)
}
}
if original == value {
if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
// EIP 2200 Original clause:
//evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.SloadGasEIP2200)
evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - WarmStorageReadCostEIP2929)
} else { // reset to original existing slot (2.2.2.2)
// EIP 2200 Original clause:
// evm.StateDB.AddRefund(params.SstoreResetGasEIP2200 - params.SloadGasEIP2200)
// - SSTORE_RESET_GAS redefined as (5000 - COLD_SLOAD_COST)
// - SLOAD_GAS redefined as WARM_STORAGE_READ_COST
// Final: (5000 - COLD_SLOAD_COST) - WARM_STORAGE_READ_COST
evm.StateDB.AddRefund((params.SstoreResetGasEIP2200 - ColdSloadCostEIP2929) - WarmStorageReadCostEIP2929)
}
}
// EIP-2200 original clause:
//return params.SloadGasEIP2200, nil // dirty update (2.2)
return cost + WarmStorageReadCostEIP2929, nil // dirty update (2.2)
}
// gasSLoadEIP2929 calculates dynamic gas for SLOAD according to EIP-2929
// For SLOAD, if the (address, storage_key) pair (where address is the address of the contract
// whose storage is being read) is not yet in accessed_storage_keys,
// charge 2100 gas and add the pair to accessed_storage_keys.
// If the pair is already in accessed_storage_keys, charge 100 gas.
func gasSLoadEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
loc := stack.peek()
slot := common.Hash(loc.Bytes32())
// Check slot presence in the access list
if _, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
// If the caller cannot afford the cost, this change will be rolled back
// If he does afford it, we can skip checking the same thing later on, during execution
evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
return ColdSloadCostEIP2929, nil
}
return WarmStorageReadCostEIP2929, nil
}
// gasExtCodeCopyEIP2929 implements extcodecopy according to EIP-2929
// EIP spec:
// > If the target is not in accessed_addresses,
// > charge COLD_ACCOUNT_ACCESS_COST gas, and add the address to accessed_addresses.
// > Otherwise, charge WARM_STORAGE_READ_COST gas.
func gasExtCodeCopyEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
// memory expansion first (dynamic part of pre-2929 implementation)
gas, err := gasExtCodeCopy(evm, contract, stack, mem, memorySize)
if err != nil {
return 0, err
}
addr := common.Address(stack.peek().Bytes20())
// Check slot presence in the access list
if !evm.StateDB.AddressInAccessList(addr) {
evm.StateDB.AddAddressToAccessList(addr)
var overflow bool
// We charge (cold-warm), since 'warm' is already charged as constantGas
if gas, overflow = math.SafeAdd(gas, ColdAccountAccessCostEIP2929-WarmStorageReadCostEIP2929); overflow {
return 0, ErrGasUintOverflow
}
return gas, nil
}
return gas, nil
}
// gasEip2929AccountCheck checks whether the first stack item (as address) is present in the access list.
// If it is, this method returns '0', otherwise 'cold-warm' gas, presuming that the opcode using it
// is also using 'warm' as constant factor.
// This method is used by:
// - extcodehash,
// - extcodesize,
// - (ext) balance
func gasEip2929AccountCheck(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
addr := common.Address(stack.peek().Bytes20())
// Check slot presence in the access list
if !evm.StateDB.AddressInAccessList(addr) {
// If the caller cannot afford the cost, this change will be rolled back
evm.StateDB.AddAddressToAccessList(addr)
// The warm storage read cost is already charged as constantGas
return ColdAccountAccessCostEIP2929 - WarmStorageReadCostEIP2929, nil
}
return 0, nil
}
func makeCallVariantGasCallEIP2929(oldCalculator gasFunc) gasFunc {
return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
addr := common.Address(stack.Back(1).Bytes20())
// Check slot presence in the access list
warmAccess := evm.StateDB.AddressInAccessList(addr)
// The WarmStorageReadCostEIP2929 (100) is already deducted in the form of a constant cost, so
// the cost to charge for cold access, if any, is Cold - Warm
coldCost := ColdAccountAccessCostEIP2929 - WarmStorageReadCostEIP2929
if !warmAccess {
evm.StateDB.AddAddressToAccessList(addr)
// Charge the remaining difference here already, to correctly calculate available
// gas for call
if !contract.UseGas(coldCost) {
return 0, ErrOutOfGas
}
}
// Now call the old calculator, which takes into account
// - create new account
// - transfer value
// - memory expansion
// - 63/64ths rule
gas, err := oldCalculator(evm, contract, stack, mem, memorySize)
if warmAccess || err != nil {
return gas, err
}
// In case of a cold access, we temporarily add the cold charge back, and also
// add it to the returned gas. By adding it to the return, it will be charged
// outside of this function, as part of the dynamic gas, and that will make it
// also become correctly reported to tracers.
contract.Gas += coldCost
return gas + coldCost, nil
}
}
var (
gasCallEIP2929 = makeCallVariantGasCallEIP2929(gasCall)
gasDelegateCallEIP2929 = makeCallVariantGasCallEIP2929(gasDelegateCall)
gasStaticCallEIP2929 = makeCallVariantGasCallEIP2929(gasStaticCall)
gasCallCodeEIP2929 = makeCallVariantGasCallEIP2929(gasCallCode)
)
func gasSelfdestructEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
var (
gas uint64
address = common.Address(stack.peek().Bytes20())
)
if !evm.StateDB.AddressInAccessList(address) {
// If the caller cannot afford the cost, this change will be rolled back
evm.StateDB.AddAddressToAccessList(address)
gas = ColdAccountAccessCostEIP2929
}
// if empty and transfers value
if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
gas += params.CreateBySelfdestructGas
}
if !evm.StateDB.HasSuicided(contract.Address()) {
evm.StateDB.AddRefund(params.SelfdestructRefundGas)
}
return gas, nil
}