2018-01-18 11:15:22 +00:00
|
|
|
/*
|
|
|
|
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/>.
|
|
|
|
*/
|
2020-07-17 14:54:12 +00:00
|
|
|
// SPDX-License-Identifier: GPL-3.0
|
2018-01-18 11:15:22 +00:00
|
|
|
/**
|
|
|
|
* Optimiser component that uses the simplification rules to simplify expressions.
|
|
|
|
*/
|
|
|
|
|
2018-10-15 09:52:35 +00:00
|
|
|
#include <libyul/optimiser/ExpressionSimplifier.h>
|
2018-01-18 11:15:22 +00:00
|
|
|
|
2018-10-15 09:52:35 +00:00
|
|
|
#include <libyul/optimiser/SimplificationRules.h>
|
2019-09-23 14:32:50 +00:00
|
|
|
#include <libyul/optimiser/OptimiserStep.h>
|
2022-04-06 16:33:42 +00:00
|
|
|
#include <libyul/optimiser/OptimizerUtilities.h>
|
2020-10-29 14:00:27 +00:00
|
|
|
#include <libyul/AST.h>
|
2022-04-06 16:33:42 +00:00
|
|
|
#include <libyul/Utilities.h>
|
|
|
|
|
|
|
|
#include <libevmasm/SemanticInformation.h>
|
2018-01-18 11:15:22 +00:00
|
|
|
|
2019-12-11 16:31:36 +00:00
|
|
|
using namespace solidity;
|
|
|
|
using namespace solidity::yul;
|
2018-01-18 11:15:22 +00:00
|
|
|
|
2019-09-23 14:32:50 +00:00
|
|
|
void ExpressionSimplifier::run(OptimiserStepContext& _context, Block& _ast)
|
|
|
|
{
|
|
|
|
ExpressionSimplifier{_context.dialect}(_ast);
|
|
|
|
}
|
|
|
|
|
2018-01-18 11:15:22 +00:00
|
|
|
void ExpressionSimplifier::visit(Expression& _expression)
|
|
|
|
{
|
|
|
|
ASTModifier::visit(_expression);
|
2020-08-03 20:42:39 +00:00
|
|
|
|
2022-03-10 17:25:00 +00:00
|
|
|
while (auto const* match = SimplificationRules::findFirstMatch(
|
|
|
|
_expression,
|
|
|
|
m_dialect,
|
|
|
|
[this](YulString _var) { return variableValue(_var); }
|
|
|
|
))
|
2022-11-23 10:51:34 +00:00
|
|
|
_expression = match->action().toExpression(debugDataOf(_expression), evmVersionFromDialect(m_dialect));
|
2022-04-06 16:33:42 +00:00
|
|
|
|
2023-08-23 02:03:44 +00:00
|
|
|
if (auto* functionCall = std::get_if<FunctionCall>(&_expression))
|
|
|
|
if (std::optional<evmasm::Instruction> instruction = toEVMInstruction(m_dialect, functionCall->functionName.name))
|
2022-04-06 16:33:42 +00:00
|
|
|
for (auto op: evmasm::SemanticInformation::readWriteOperations(*instruction))
|
|
|
|
if (op.startParameter && op.lengthParameter)
|
|
|
|
{
|
|
|
|
Expression& startArgument = functionCall->arguments.at(*op.startParameter);
|
|
|
|
Expression const& lengthArgument = functionCall->arguments.at(*op.lengthParameter);
|
|
|
|
if (
|
|
|
|
knownToBeZero(lengthArgument) &&
|
|
|
|
!knownToBeZero(startArgument) &&
|
2023-08-23 02:03:44 +00:00
|
|
|
!std::holds_alternative<FunctionCall>(startArgument)
|
2022-04-06 16:33:42 +00:00
|
|
|
)
|
|
|
|
startArgument = Literal{debugDataOf(startArgument), LiteralKind::Number, "0"_yulstring, {}};
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
bool ExpressionSimplifier::knownToBeZero(Expression const& _expression) const
|
|
|
|
{
|
2023-08-23 02:03:44 +00:00
|
|
|
if (auto const* literal = std::get_if<Literal>(&_expression))
|
2022-04-06 16:33:42 +00:00
|
|
|
return valueOfLiteral(*literal) == 0;
|
2023-08-23 02:03:44 +00:00
|
|
|
else if (auto const* identifier = std::get_if<Identifier>(&_expression))
|
2022-04-06 16:33:42 +00:00
|
|
|
return valueOfIdentifier(identifier->name) == 0;
|
|
|
|
else
|
|
|
|
return false;
|
2018-01-18 11:15:22 +00:00
|
|
|
}
|