mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
72 lines
2.2 KiB
C++
72 lines
2.2 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/>.
|
|
*/
|
|
/**
|
|
* Optimisation stage that replaces expressions known to be the current value of a variable
|
|
* in scope by a reference to that variable.
|
|
*/
|
|
|
|
#include <libyul/optimiser/CommonSubexpressionEliminator.h>
|
|
|
|
#include <libyul/optimiser/Metrics.h>
|
|
#include <libyul/optimiser/SyntacticalEquality.h>
|
|
#include <libyul/Exceptions.h>
|
|
#include <libyul/AsmData.h>
|
|
|
|
using namespace std;
|
|
using namespace dev;
|
|
using namespace yul;
|
|
|
|
void CommonSubexpressionEliminator::visit(Expression& _e)
|
|
{
|
|
// We visit the inner expression first to first simplify inner expressions,
|
|
// which hopefully allows more matches.
|
|
// Note that the DataFlowAnalyzer itself only has code for visiting Statements,
|
|
// so this basically invokes the AST walker directly and thus post-visiting
|
|
// is also fine with regards to data flow analysis.
|
|
DataFlowAnalyzer::visit(_e);
|
|
|
|
if (_e.type() == typeid(Identifier))
|
|
{
|
|
Identifier& identifier = boost::get<Identifier>(_e);
|
|
YulString name = identifier.name;
|
|
if (m_value.count(name))
|
|
{
|
|
assertThrow(m_value.at(name), OptimizerException, "");
|
|
if (m_value.at(name)->type() == typeid(Identifier))
|
|
{
|
|
YulString value = boost::get<Identifier>(*m_value.at(name)).name;
|
|
assertThrow(inScope(value), OptimizerException, "");
|
|
_e = Identifier{locationOf(_e), value};
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// TODO this search is rather inefficient.
|
|
for (auto const& var: m_value)
|
|
{
|
|
assertThrow(var.second, OptimizerException, "");
|
|
assertThrow(inScope(var.first), OptimizerException, "");
|
|
if (SyntacticalEqualityChecker::equal(_e, *var.second))
|
|
{
|
|
_e = Identifier{locationOf(_e), var.first};
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|