GasMeter::GasConsumption GasMeter::estimateMax(AssemblyItem const& _item)
{
GasConsumption gas;
switch (_item.type())
{
case Push:
case PushTag:
case PushData:
case PushString:
case PushSub:
case PushSubSize:
case PushProgramSize:
case PushLibraryAddress:
gas = runGas(Instruction::PUSH1);
break;
case Tag:
gas = runGas(Instruction::JUMPDEST);
break;
case Operation:
{
ExpressionClasses& classes = m_state->expressionClasses();
gas = runGas(_item.instruction());
switch (_item.instruction())
{
case Instruction::SSTORE:
{
ExpressionClasses::Id slot = m_state->relativeStackElement(0);
ExpressionClasses::Id value = m_state->relativeStackElement(-1);
if (classes.knownZero(value) || (
m_state->storageContent().count(slot) &&
classes.knownNonZero(m_state->storageContent().at(slot))
))
gas += GasCosts::sstoreResetGas; //@todo take refunds into account
else
gas += GasCosts::sstoreSetGas;
break;
}
case Instruction::SLOAD:
gas += GasCosts::sloadGas;
break;
case Instruction::RETURN:
gas += memoryGas(0, -1);
break;
case Instruction::MLOAD:
case Instruction::MSTORE:
gas += memoryGas(classes.find(Instruction::ADD, {
m_state->relativeStackElement(0),
classes.find(AssemblyItem(32))
}));
break;
case Instruction::MSTORE8:
gas += memoryGas(classes.find(Instruction::ADD, {
m_state->relativeStackElement(0),
classes.find(AssemblyItem(1))
}));
break;
case Instruction::SHA3:
gas = GasCosts::sha3Gas;
gas += wordGas(GasCosts::sha3WordGas, m_state->relativeStackElement(-1));
gas += memoryGas(0, -1);
break;
case Instruction::CALLDATACOPY:
case Instruction::CODECOPY:
gas += memoryGas(0, -2);
gas += wordGas(GasCosts::copyGas, m_state->relativeStackElement(-2));
break;
case Instruction::EXTCODECOPY:
gas += memoryGas(-1, -3);
gas += wordGas(GasCosts::copyGas, m_state->relativeStackElement(-3));
break;
case Instruction::LOG0:
case Instruction::LOG1:
case Instruction::LOG2:
case Instruction::LOG3:
case Instruction::LOG4:
{
unsigned n = unsigned(_item.instruction()) - unsigned(Instruction::LOG0);
gas = GasCosts::logGas + GasCosts::logTopicGas * n;
gas += memoryGas(0, -1);
if (u256 const* value = classes.knownConstant(m_state->relativeStackElement(-1)))
gas += GasCosts::logDataGas * (*value);
else
gas = GasConsumption::infinite();
break;
}
case Instruction::CALL:
case Instruction::CALLCODE:
case Instruction::DELEGATECALL:
{
gas = GasCosts::callGas;
if (u256 const* value = classes.knownConstant(m_state->relativeStackElement(0)))
gas += (*value);
else
gas = GasConsumption::infinite();
if (_item.instruction() == Instruction::CALL)
gas += GasCosts::callNewAccountGas; // We very rarely know whether the address exists.
int valueSize = _item.instruction() == Instruction::DELEGATECALL ? 0 : 1;
if (!classes.knownZero(m_state->relativeStackElement(-1 - valueSize)))
gas += GasCosts::callValueTransferGas;
gas += memoryGas(-2 - valueSize, -3 - valueSize);
gas += memoryGas(-4 - valueSize, -5 - valueSize);
break;
}
case Instruction::CREATE:
gas = GasCosts::createGas;
gas += memoryGas(-1, -2);
break;
case Instruction::EXP:
gas = GasCosts::expGas;
if (u256 const* value = classes.knownConstant(m_state->relativeStackElement(-1)))
gas += GasCosts::expByteGas * (32 - (h256(*value).firstBitSet() / 8));
else
gas += GasCosts::expByteGas * 32;
break;
default:
break;
}
break;
}
default:
gas = GasConsumption::infinite();
break;
}
m_state->feedItem(_item);
return gas;
}
KnownState::StoreOperation KnownState::feedItem(AssemblyItem const& _item, bool _copyItem)
{
StoreOperation op;
if (_item.type() == Tag)
{
// can be ignored
}
else if (_item.type() != Operation)
{
assertThrow(_item.deposit() == 1, InvalidDeposit, "");
if (_item.pushedValue())
// only available after assembly stage, should not be used for optimisation
setStackElement(++m_stackHeight, m_expressionClasses->find(*_item.pushedValue()));
else
setStackElement(++m_stackHeight, m_expressionClasses->find(_item, {}, _copyItem));
}
else
{
Instruction instruction = _item.instruction();
InstructionInfo info = instructionInfo(instruction);
if (SemanticInformation::isDupInstruction(_item))
setStackElement(
m_stackHeight + 1,
stackElement(
m_stackHeight - int(instruction) + int(Instruction::DUP1),
_item.getLocation()
)
);
else if (SemanticInformation::isSwapInstruction(_item))
swapStackElements(
m_stackHeight,
m_stackHeight - 1 - int(instruction) + int(Instruction::SWAP1),
_item.getLocation()
);
else if (instruction != Instruction::POP)
{
vector<Id> arguments(info.args);
for (int i = 0; i < info.args; ++i)
arguments[i] = stackElement(m_stackHeight - i, _item.getLocation());
if (_item.instruction() == Instruction::SSTORE)
op = storeInStorage(arguments[0], arguments[1], _item.getLocation());
else if (_item.instruction() == Instruction::SLOAD)
setStackElement(
m_stackHeight + _item.deposit(),
loadFromStorage(arguments[0], _item.getLocation())
);
else if (_item.instruction() == Instruction::MSTORE)
op = storeInMemory(arguments[0], arguments[1], _item.getLocation());
else if (_item.instruction() == Instruction::MLOAD)
setStackElement(
m_stackHeight + _item.deposit(),
loadFromMemory(arguments[0], _item.getLocation())
);
else if (_item.instruction() == Instruction::SHA3)
setStackElement(
m_stackHeight + _item.deposit(),
applySha3(arguments.at(0), arguments.at(1), _item.getLocation())
);
else
{
if (SemanticInformation::invalidatesMemory(_item.instruction()))
resetMemory();
if (SemanticInformation::invalidatesStorage(_item.instruction()))
resetStorage();
assertThrow(info.ret <= 1, InvalidDeposit, "");
if (info.ret == 1)
setStackElement(
m_stackHeight + _item.deposit(),
m_expressionClasses->find(_item, arguments, _copyItem)
);
}
}
m_stackElements.erase(
m_stackElements.upper_bound(m_stackHeight + _item.deposit()),
m_stackElements.end()
);
m_stackHeight += _item.deposit();
}
return op;
}