mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
144 lines
3.8 KiB
C++
144 lines
3.8 KiB
C++
/*(
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This file is part of solidity.
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solidity is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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solidity is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with solidity. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* Optimisation stage that replaces variables by their most recently assigned expressions.
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*/
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#include <libjulia/optimiser/Rematerialiser.h>
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#include <libjulia/optimiser/ASTCopier.h>
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#include <libjulia/optimiser/NameCollector.h>
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#include <libsolidity/inlineasm/AsmData.h>
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#include <libjulia/optimiser/Semantics.h>
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#include <libdevcore/CommonData.h>
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using namespace std;
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using namespace dev;
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using namespace dev::julia;
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void Rematerialiser::operator()(Assignment& _assignment)
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{
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set<string> names;
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for (auto const& var: _assignment.variableNames)
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names.insert(var.name);
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handleAssignment(names, _assignment.value.get());
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}
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void Rematerialiser::operator()(VariableDeclaration& _varDecl)
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{
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set<string> names;
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for (auto const& var: _varDecl.variables)
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names.insert(var.name);
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handleAssignment(names, _varDecl.value.get());
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}
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void Rematerialiser::operator()(If& _if)
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{
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ASTModifier::operator()(_if);
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Assignments ass;
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ass(_if.body);
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handleAssignment(ass.names(), nullptr);
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}
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void Rematerialiser::operator()(Switch& _switch)
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{
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boost::apply_visitor(*this, *_switch.expression);
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set<string> assignedVariables;
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for (auto& _case: _switch.cases)
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{
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(*this)(_case.body);
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Assignments ass;
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ass(_case.body);
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assignedVariables += ass.names();
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// This is a little too destructive, we could retain the old replacements.
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handleAssignment(ass.names(), nullptr);
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}
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handleAssignment(assignedVariables, nullptr);
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}
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void Rematerialiser::operator()(ForLoop& _for)
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{
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(*this)(_for.pre);
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Assignments ass;
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ass(_for.body);
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ass(_for.post);
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handleAssignment(ass.names(), nullptr);
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visit(*_for.condition);
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(*this)(_for.body);
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(*this)(_for.post);
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handleAssignment(ass.names(), nullptr);
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}
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void Rematerialiser::handleAssignment(set<string> const& _variables, Expression* _value)
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{
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MovableChecker movableChecker;
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if (_value)
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{
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visit(*_value);
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movableChecker.visit(*_value);
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}
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if (_variables.size() == 1)
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{
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string const& name = *_variables.begin();
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if (movableChecker.movable() && _value)
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// TODO Plus heuristic about size of value
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// TODO If _value is null, we could use zero.
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m_substitutions[name] = _value;
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else
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m_substitutions.erase(name);
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}
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// Disallow substitutions that use a variable that will be reassigned by this assignment.
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for (auto const& name: _variables)
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for (auto const& ref: m_referencedBy[name])
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m_substitutions.erase(ref);
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// Update the fact which variables are referenced by the newly assigned variables
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for (auto const& name: _variables)
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{
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for (auto const& ref: m_references[name])
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m_referencedBy[ref].erase(name);
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m_references[name].clear();
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}
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auto const& referencedVariables = movableChecker.referencedVariables();
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for (auto const& name: _variables)
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{
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m_references[name] = referencedVariables;
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for (auto const& ref: referencedVariables)
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m_referencedBy[ref].insert(name);
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}
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}
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void Rematerialiser::visit(Expression& _e)
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{
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if (_e.type() == typeid(Identifier))
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{
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Identifier& identifier = boost::get<Identifier>(_e);
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if (m_substitutions.count(identifier.name))
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{
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string name = identifier.name;
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_e = (ASTCopier{}).translate(*m_substitutions.at(name));
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}
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}
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ASTModifier::visit(_e);
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}
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