1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/*
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 <http://www.gnu.org/licenses/>.
*/
/** @file GasMeter.cpp
* @author Christian <c@ethdev.com>
* @date 2015
*/
#pragma once
#include <libevmasm/ExpressionClasses.h>
#include <libevmasm/AssemblyItem.h>
#include <liblangutil/EVMVersion.h>
#include <ostream>
#include <tuple>
namespace dev
{
namespace eth
{
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;
inline unsigned extCodeGas(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::tangerineWhistle() ? 700 : 20;
}
inline unsigned balanceGas(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::tangerineWhistle() ? 400 : 20;
}
static unsigned const expGas = 10;
inline unsigned expByteGas(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::spuriousDragon() ? 50 : 10;
}
static unsigned const keccak256Gas = 30;
static unsigned const keccak256WordGas = 6;
inline unsigned sloadGas(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::tangerineWhistle() ? 200 : 50;
}
static unsigned const sstoreSetGas = 20000;
static unsigned const sstoreResetGas = 5000;
static unsigned const sstoreRefundGas = 15000;
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(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::tangerineWhistle() ? 700 : 40;
}
static unsigned const callStipend = 2300;
static unsigned const callValueTransferGas = 9000;
static unsigned const callNewAccountGas = 25000;
inline unsigned selfdestructGas(EVMVersion _evmVersion)
{
return _evmVersion >= EVMVersion::tangerineWhistle() ? 5000 : 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;
static unsigned const txDataNonZeroGas = 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(_value), isInfinite(_infinite) {}
static GasConsumption infinite() { return GasConsumption(0, true); }
GasConsumption& operator+=(GasConsumption const& _other);
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<KnownState> const& _state, solidity::EVMVersion _evmVersion, u256 const& _largestMemoryAccess = 0):
m_state(_state), m_evmVersion(_evmVersion), m_largestMemoryAccess(_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);
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<KnownState> m_state;
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;
}
}
}
|
