solidity/libyul/optimiser/LoadResolver.cpp
2020-12-03 19:10:05 +01:00

80 lines
2.3 KiB
C++

/*
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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Optimisation stage that replaces expressions of type ``sload(x)`` by the value
* currently stored in storage, if known.
*/
#include <libyul/optimiser/LoadResolver.h>
#include <libyul/backends/evm/EVMDialect.h>
#include <libyul/optimiser/Semantics.h>
#include <libyul/optimiser/CallGraphGenerator.h>
#include <libyul/SideEffects.h>
#include <libyul/AST.h>
using namespace std;
using namespace solidity;
using namespace solidity::yul;
void LoadResolver::run(OptimiserStepContext& _context, Block& _ast)
{
bool containsMSize = MSizeFinder::containsMSize(_context.dialect, _ast);
LoadResolver{
_context.dialect,
SideEffectsPropagator::sideEffects(_context.dialect, CallGraphGenerator::callGraph(_ast)),
!containsMSize
}(_ast);
}
void LoadResolver::visit(Expression& _e)
{
DataFlowAnalyzer::visit(_e);
if (FunctionCall const* funCall = std::get_if<FunctionCall>(&_e))
for (auto location: { StoreLoadLocation::Memory, StoreLoadLocation::Storage })
if (funCall->functionName.name == m_loadFunctionName[static_cast<unsigned>(location)])
{
tryResolve(_e, location, funCall->arguments);
break;
}
}
void LoadResolver::tryResolve(
Expression& _e,
StoreLoadLocation _location,
vector<Expression> const& _arguments
)
{
if (_arguments.empty() || !holds_alternative<Identifier>(_arguments.at(0)))
return;
YulString key = std::get<Identifier>(_arguments.at(0)).name;
if (
_location == StoreLoadLocation::Storage &&
m_storage.values.count(key)
)
_e = Identifier{locationOf(_e), m_storage.values[key]};
else if (
m_optimizeMLoad &&
_location == StoreLoadLocation::Memory &&
m_memory.values.count(key)
)
_e = Identifier{locationOf(_e), m_memory.values[key]};
}