/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see .
*/
// SPDX-License-Identifier: GPL-3.0
/** @file GasMeter.cpp
* @author Christian
* @date 2015
*
* Utilities for tracking gas costs.
*
* With respect to EIP-2929, we do not track warm accounts or storage slots and they are always
* charged the worst-case, i.e., cold-access.
*/
#pragma once
#include
#include
#include
#include
#include
#include
namespace solidity::evmasm
{
class KnownState;
namespace GasCosts
{
static unsigned const stackLimit = 1024;
static unsigned const tier0Gas = 0;
static unsigned const tier1Gas = 2;
static unsigned const tier2Gas = 3;
static unsigned const tier3Gas = 5;
static unsigned const tier4Gas = 8;
static unsigned const tier5Gas = 10;
static unsigned const tier6Gas = 20;
static unsigned const tier7Gas = 0;
static unsigned const expGas = 10;
inline unsigned expByteGas(langutil::EVMVersion _evmVersion)
{
return _evmVersion >= langutil::EVMVersion::spuriousDragon() ? 50 : 10;
}
static unsigned const keccak256Gas = 30;
static unsigned const keccak256WordGas = 6;
/// Corresponds to COLD_SLOAD_COST from EIP-2929
static unsigned const coldSloadCost = 2100;
/// Corresponds to COLD_ACCOUNT_ACCESS_COST from EIP-2929
static unsigned const coldAccountAccessCost = 2600;
/// Corresponds to WARM_STORAGE_READ_COST from EIP-2929
static unsigned const warmStorageReadCost = 100;
inline unsigned sloadGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldSloadCost;
else if (_evmVersion >= langutil::EVMVersion::istanbul())
return 800;
else if (_evmVersion >= langutil::EVMVersion::tangerineWhistle())
return 200;
else
return 50;
}
/// Corresponds to SSTORE_SET_GAS
static unsigned const sstoreSetGas = 20000;
/// Corresponds to SSTORE_RESET_GAS from EIP-2929
static unsigned const sstoreResetGas = 5000 - coldSloadCost;
static unsigned const sstoreRefundGas = 15000;
inline static unsigned totalSstoreSetGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return sstoreSetGas + coldSloadCost;
else
return sstoreSetGas;
}
/// Corresponds to SSTORE_RESET_GAS from EIP-2929
/// For Berlin, the maximum is SSTORE_RESET_GAS + COLD_SLOAD_COST = 5000
/// For previous versions, it's a fixed 5000
inline unsigned totalSstoreResetGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return sstoreResetGas + coldSloadCost;
else
return 5000;
}
inline unsigned extCodeGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldAccountAccessCost;
else if (_evmVersion >= langutil::EVMVersion::tangerineWhistle())
return 700;
else
return 20;
}
inline unsigned balanceGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldAccountAccessCost;
else if (_evmVersion >= langutil::EVMVersion::istanbul())
return 700;
else if (_evmVersion >= langutil::EVMVersion::tangerineWhistle())
return 400;
else
return 20;
}
static unsigned const jumpdestGas = 1;
static unsigned const logGas = 375;
static unsigned const logDataGas = 8;
static unsigned const logTopicGas = 375;
static unsigned const createGas = 32000;
inline unsigned callGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldAccountAccessCost;
else if (_evmVersion >= langutil::EVMVersion::tangerineWhistle())
return 700;
else
return 40;
}
static unsigned const callStipend = 2300;
static unsigned const callValueTransferGas = 9000;
static unsigned const callNewAccountGas = 25000;
inline unsigned selfdestructGas(langutil::EVMVersion _evmVersion)
{
if (_evmVersion >= langutil::EVMVersion::berlin())
return coldAccountAccessCost;
else if (_evmVersion >= langutil::EVMVersion::tangerineWhistle())
return 5000;
else
return 0;
}
static unsigned const selfdestructRefundGas = 24000;
static unsigned const memoryGas = 3;
static unsigned const quadCoeffDiv = 512;
static unsigned const createDataGas = 200;
static unsigned const txGas = 21000;
static unsigned const txCreateGas = 53000;
static unsigned const txDataZeroGas = 4;
inline unsigned txDataNonZeroGas(langutil::EVMVersion _evmVersion)
{
return _evmVersion >= langutil::EVMVersion::istanbul() ? 16 : 68;
}
static unsigned const copyGas = 3;
}
/**
* Class that helps computing the maximum gas consumption for instructions.
* Has to be initialized with a certain known state that will be automatically updated for
* each call to estimateMax. These calls have to supply strictly subsequent AssemblyItems.
* A new gas meter has to be constructed (with a new state) for control flow changes.
*/
class GasMeter
{
public:
struct GasConsumption
{
GasConsumption(unsigned _value = 0, bool _infinite = false): value(_value), isInfinite(_infinite) {}
GasConsumption(u256 _value, bool _infinite = false): value(std::move(_value)), isInfinite(_infinite) {}
static GasConsumption infinite() { return GasConsumption(0, true); }
GasConsumption& operator+=(GasConsumption const& _other);
GasConsumption operator+(GasConsumption const& _other) const
{
GasConsumption result = *this;
result += _other;
return result;
}
bool operator<(GasConsumption const& _other) const
{
return std::make_pair(isInfinite, value) < std::make_pair(_other.isInfinite, _other.value);
}
u256 value;
bool isInfinite;
};
/// Constructs a new gas meter given the current state.
GasMeter(std::shared_ptr _state, langutil::EVMVersion _evmVersion, u256 _largestMemoryAccess = 0):
m_state(std::move(_state)), m_evmVersion(_evmVersion), m_largestMemoryAccess(std::move(_largestMemoryAccess)) {}
/// @returns an upper bound on the gas consumed by the given instruction and updates
/// the state.
/// @param _inculdeExternalCosts if true, include costs caused by other contracts in calls.
GasConsumption estimateMax(AssemblyItem const& _item, bool _includeExternalCosts = true);
u256 const& largestMemoryAccess() const { return m_largestMemoryAccess; }
/// @returns gas costs for simple instructions with constant gas costs (that do not
/// change with EVM versions)
static unsigned runGas(Instruction _instruction);
/// @returns the gas cost of the supplied data, depending whether it is in creation code, or not.
/// In case of @a _inCreation, the data is only sent as a transaction and is not stored, whereas
/// otherwise code will be stored and have to pay "createDataGas" cost.
static u256 dataGas(bytes const& _data, bool _inCreation, langutil::EVMVersion _evmVersion);
/// @returns the gas cost of non-zero data of the supplied length, depending whether it is in creation code, or not.
/// In case of @a _inCreation, the data is only sent as a transaction and is not stored, whereas
/// otherwise code will be stored and have to pay "createDataGas" cost.
static u256 dataGas(uint64_t _length, bool _inCreation, langutil::EVMVersion _evmVersion);
private:
/// @returns _multiplier * (_value + 31) / 32, if _value is a known constant and infinite otherwise.
GasConsumption wordGas(u256 const& _multiplier, ExpressionClasses::Id _value);
/// @returns the gas needed to access the given memory position.
/// @todo this assumes that memory was never accessed before and thus over-estimates gas usage.
GasConsumption memoryGas(ExpressionClasses::Id _position);
/// @returns the memory gas for accessing the memory at a specific offset for a number of bytes
/// given as values on the stack at the given relative positions.
GasConsumption memoryGas(int _stackPosOffset, int _stackPosSize);
std::shared_ptr m_state;
langutil::EVMVersion m_evmVersion;
/// Largest point where memory was accessed since the creation of this object.
u256 m_largestMemoryAccess;
};
inline std::ostream& operator<<(std::ostream& _str, GasMeter::GasConsumption const& _consumption)
{
if (_consumption.isInfinite)
return _str << "[???]";
else
return _str << std::dec << _consumption.value;
}
}