solidity/libyul/optimiser/LoadResolver.cpp

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/*
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
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/**
* Optimisation stage that replaces expressions of type ``sload(x)`` by the value
* currently stored in storage, if known.
*/
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#include <libyul/optimiser/LoadResolver.h>
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#include <libyul/backends/evm/EVMDialect.h>
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#include <libyul/optimiser/Semantics.h>
#include <libyul/optimiser/CallGraphGenerator.h>
#include <libyul/SideEffects.h>
#include <libyul/AST.h>
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using namespace std;
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using namespace solidity;
using namespace solidity::yul;
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void LoadResolver::run(OptimiserStepContext& _context, Block& _ast)
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{
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bool containsMSize = MSizeFinder::containsMSize(_context.dialect, _ast);
LoadResolver{
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_context.dialect,
SideEffectsPropagator::sideEffects(_context.dialect, CallGraphGenerator::callGraph(_ast)),
!containsMSize
}(_ast);
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}
void LoadResolver::visit(Expression& _e)
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{
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;
}
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}
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)
{
if (auto value = util::valueOrNullptr(m_storage, key))
_e = Identifier{locationOf(_e), *value};
}
else if (m_optimizeMLoad && _location == StoreLoadLocation::Memory)
if (auto value = util::valueOrNullptr(m_memory, key))
_e = Identifier{locationOf(_e), *value};
}