solidity/libyul/optimiser/ConditionalSimplifier.cpp
2020-01-07 15:51:50 +01:00

94 lines
2.5 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/>.
*/
#include <libyul/optimiser/ConditionalSimplifier.h>
#include <libyul/optimiser/Semantics.h>
#include <libyul/AsmData.h>
#include <libyul/Utilities.h>
#include <libyul/optimiser/NameCollector.h>
#include <libsolutil/CommonData.h>
#include <libsolutil/Visitor.h>
using namespace std;
using namespace solidity;
using namespace solidity::yul;
using namespace solidity::util;
void ConditionalSimplifier::operator()(Switch& _switch)
{
visit(*_switch.expression);
if (!holds_alternative<Identifier>(*_switch.expression))
{
ASTModifier::operator()(_switch);
return;
}
YulString expr = std::get<Identifier>(*_switch.expression).name;
for (auto& _case: _switch.cases)
{
if (_case.value)
{
(*this)(*_case.value);
_case.body.statements.insert(_case.body.statements.begin(),
Assignment{
_case.body.location,
{Identifier{_case.body.location, expr}},
make_unique<Expression>(*_case.value)
}
);
}
(*this)(_case.body);
}
}
void ConditionalSimplifier::operator()(Block& _block)
{
iterateReplacing(
_block.statements,
[&](Statement& _s) -> std::optional<vector<Statement>>
{
visit(_s);
if (holds_alternative<If>(_s))
{
If& _if = std::get<If>(_s);
if (
holds_alternative<Identifier>(*_if.condition) &&
!_if.body.statements.empty() &&
TerminationFinder(m_dialect).controlFlowKind(_if.body.statements.back()) !=
TerminationFinder::ControlFlow::FlowOut
)
{
YulString condition = std::get<Identifier>(*_if.condition).name;
langutil::SourceLocation location = _if.location;
return make_vector<Statement>(
std::move(_s),
Assignment{
location,
{Identifier{location, condition}},
make_unique<Expression>(Literal{
location,
LiteralKind::Number,
"0"_yulstring,
{}
})
}
);
}
}
return {};
}
);
}