mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
83 lines
2.8 KiB
C++
83 lines
2.8 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
|
|
#pragma once
|
|
|
|
#include <libyul/optimiser/ASTWalker.h>
|
|
#include <libyul/optimiser/OptimiserStep.h>
|
|
|
|
namespace solidity::yul
|
|
{
|
|
struct Dialect;
|
|
struct OptimiserStepContext;
|
|
class TypeInfo;
|
|
|
|
/**
|
|
* Simplifies several control-flow structures:
|
|
* - replace if with empty body with pop(condition)
|
|
* - remove empty default switch case
|
|
* - remove empty switch case if no default case exists
|
|
* - replace switch with no cases with pop(expression)
|
|
* - turn switch with single case into if
|
|
* - replace switch with only default case with pop(expression) and body
|
|
* - replace switch with const expr with matching case body
|
|
* - replace ``for`` with terminating control flow and without other break/continue by ``if``
|
|
* - remove ``leave`` at the end of a function.
|
|
*
|
|
* None of these operations depend on the data flow. The StructuralSimplifier
|
|
* performs similar tasks that do depend on data flow.
|
|
*
|
|
* The ControlFlowSimplifier does record the presence or absence of ``break``
|
|
* and ``continue`` statements during its traversal.
|
|
*
|
|
* Prerequisite: Disambiguator, FunctionHoister, ForLoopInitRewriter.
|
|
*
|
|
* Important: Introduces EVM opcodes and thus can only be used on EVM code for now.
|
|
*/
|
|
class ControlFlowSimplifier: public ASTModifier
|
|
{
|
|
public:
|
|
static constexpr char const* name{"ControlFlowSimplifier"};
|
|
static void run(OptimiserStepContext&, Block& _ast);
|
|
|
|
using ASTModifier::operator();
|
|
void operator()(Break&) override { ++m_numBreakStatements; }
|
|
void operator()(Continue&) override { ++m_numContinueStatements; }
|
|
void operator()(Block& _block) override;
|
|
void operator()(FunctionDefinition& _funDef) override;
|
|
|
|
void visit(Statement& _st) override;
|
|
|
|
private:
|
|
ControlFlowSimplifier(Dialect const& _dialect, TypeInfo const& _typeInfo):
|
|
m_dialect(_dialect),
|
|
m_typeInfo(_typeInfo)
|
|
{}
|
|
|
|
void simplify(std::vector<Statement>& _statements);
|
|
|
|
std::optional<std::vector<Statement>> reduceNoCaseSwitch(Switch& _switchStmt) const;
|
|
std::optional<std::vector<Statement>> reduceSingleCaseSwitch(Switch& _switchStmt) const;
|
|
|
|
Dialect const& m_dialect;
|
|
TypeInfo const& m_typeInfo;
|
|
size_t m_numBreakStatements = 0;
|
|
size_t m_numContinueStatements = 0;
|
|
};
|
|
|
|
}
|