mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
258 lines
8.2 KiB
C++
258 lines
8.2 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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* Optimiser component that performs function inlining for arbitrary functions.
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*/
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#include <libyul/optimiser/FullInliner.h>
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#include <libyul/optimiser/ASTCopier.h>
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#include <libyul/optimiser/ASTWalker.h>
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#include <libyul/optimiser/NameCollector.h>
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#include <libyul/optimiser/OptimizerUtilities.h>
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#include <libyul/optimiser/Metrics.h>
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#include <libyul/optimiser/SSAValueTracker.h>
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#include <libyul/Exceptions.h>
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#include <libyul/AsmData.h>
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#include <libdevcore/CommonData.h>
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#include <libdevcore/Visitor.h>
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#include <boost/range/adaptor/reversed.hpp>
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using namespace std;
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using namespace dev;
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using namespace yul;
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void FullInliner::run(OptimiserStepContext& _context, Block& _ast)
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{
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FullInliner{_ast, _context.dispenser}.run();
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}
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FullInliner::FullInliner(Block& _ast, NameDispenser& _dispenser):
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m_ast(_ast), m_nameDispenser(_dispenser)
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{
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// Determine constants
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SSAValueTracker tracker;
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tracker(m_ast);
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for (auto const& ssaValue: tracker.values())
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if (ssaValue.second && ssaValue.second->type() == typeid(Literal))
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m_constants.emplace(ssaValue.first);
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// Store size of global statements.
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m_functionSizes[YulString{}] = CodeSize::codeSize(_ast);
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map<YulString, size_t> references = ReferencesCounter::countReferences(m_ast);
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for (auto& statement: m_ast.statements)
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{
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if (statement.type() != typeid(FunctionDefinition))
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continue;
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FunctionDefinition& fun = boost::get<FunctionDefinition>(statement);
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m_functions[fun.name] = &fun;
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// Always inline functions that are only called once.
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if (references[fun.name] == 1)
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m_singleUse.emplace(fun.name);
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updateCodeSize(fun);
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}
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}
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void FullInliner::run()
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{
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for (auto& statement: m_ast.statements)
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if (statement.type() == typeid(Block))
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handleBlock({}, boost::get<Block>(statement));
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// TODO it might be good to determine a visiting order:
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// first handle functions that are called from many places.
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for (auto const& fun: m_functions)
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{
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handleBlock(fun.second->name, fun.second->body);
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updateCodeSize(*fun.second);
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}
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}
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bool FullInliner::shallInline(FunctionCall const& _funCall, YulString _callSite)
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{
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// No recursive inlining
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if (_funCall.functionName.name == _callSite)
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return false;
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FunctionDefinition* calledFunction = function(_funCall.functionName.name);
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if (!calledFunction)
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return false;
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if (recursive(*calledFunction))
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return false;
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// Inline really, really tiny functions
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size_t size = m_functionSizes.at(calledFunction->name);
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if (size <= 1)
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return true;
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// Do not inline into already big functions.
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if (m_functionSizes.at(_callSite) > 45)
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return false;
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if (m_singleUse.count(calledFunction->name))
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return true;
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// Constant arguments might provide a means for further optimization, so they cause a bonus.
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bool constantArg = false;
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for (auto const& argument: _funCall.arguments)
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if (argument.type() == typeid(Literal) || (
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argument.type() == typeid(Identifier) &&
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m_constants.count(boost::get<Identifier>(argument).name)
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))
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{
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constantArg = true;
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break;
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}
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return (size < 6 || (constantArg && size < 12));
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}
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void FullInliner::tentativelyUpdateCodeSize(YulString _function, YulString _callSite)
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{
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m_functionSizes.at(_callSite) += m_functionSizes.at(_function);
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}
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void FullInliner::updateCodeSize(FunctionDefinition const& _fun)
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{
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m_functionSizes[_fun.name] = CodeSize::codeSize(_fun.body);
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}
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void FullInliner::handleBlock(YulString _currentFunctionName, Block& _block)
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{
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InlineModifier{*this, m_nameDispenser, _currentFunctionName}(_block);
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}
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bool FullInliner::recursive(FunctionDefinition const& _fun) const
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{
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map<YulString, size_t> references = ReferencesCounter::countReferences(_fun);
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return references[_fun.name] > 0;
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}
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void InlineModifier::operator()(Block& _block)
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{
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function<boost::optional<vector<Statement>>(Statement&)> f = [&](Statement& _statement) -> boost::optional<vector<Statement>> {
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visit(_statement);
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return tryInlineStatement(_statement);
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};
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iterateReplacing(_block.statements, f);
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}
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boost::optional<vector<Statement>> InlineModifier::tryInlineStatement(Statement& _statement)
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{
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// Only inline for expression statements, assignments and variable declarations.
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Expression* e = boost::apply_visitor(GenericFallbackReturnsVisitor<Expression*, ExpressionStatement, Assignment, VariableDeclaration>(
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[](ExpressionStatement& _s) { return &_s.expression; },
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[](Assignment& _s) { return _s.value.get(); },
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[](VariableDeclaration& _s) { return _s.value.get(); }
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), _statement);
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if (e)
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{
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// Only inline direct function calls.
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FunctionCall* funCall = boost::apply_visitor(GenericFallbackReturnsVisitor<FunctionCall*, FunctionCall&>(
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[](FunctionCall& _e) { return &_e; }
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), *e);
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if (funCall && m_driver.shallInline(*funCall, m_currentFunction))
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return performInline(_statement, *funCall);
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}
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return {};
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}
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vector<Statement> InlineModifier::performInline(Statement& _statement, FunctionCall& _funCall)
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{
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vector<Statement> newStatements;
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map<YulString, YulString> variableReplacements;
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FunctionDefinition* function = m_driver.function(_funCall.functionName.name);
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assertThrow(!!function, OptimizerException, "Attempt to inline invalid function.");
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m_driver.tentativelyUpdateCodeSize(function->name, m_currentFunction);
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// helper function to create a new variable that is supposed to model
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// an existing variable.
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auto newVariable = [&](TypedName const& _existingVariable, Expression* _value) {
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YulString newName = m_nameDispenser.newName(_existingVariable.name);
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variableReplacements[_existingVariable.name] = newName;
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VariableDeclaration varDecl{_funCall.location, {{_funCall.location, newName, _existingVariable.type}}, {}};
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if (_value)
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varDecl.value = make_unique<Expression>(std::move(*_value));
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else
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varDecl.value = make_unique<Expression>(Literal{{}, LiteralKind::Number, YulString{"0"}, {}});
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newStatements.emplace_back(std::move(varDecl));
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};
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for (size_t i = 0; i < _funCall.arguments.size(); ++i)
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newVariable(function->parameters[i], &_funCall.arguments[i]);
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for (auto const& var: function->returnVariables)
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newVariable(var, nullptr);
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Statement newBody = BodyCopier(m_nameDispenser, variableReplacements)(function->body);
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newStatements += std::move(boost::get<Block>(newBody).statements);
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boost::apply_visitor(GenericFallbackVisitor<Assignment, VariableDeclaration>{
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[&](Assignment& _assignment)
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{
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for (size_t i = 0; i < _assignment.variableNames.size(); ++i)
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newStatements.emplace_back(Assignment{
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_assignment.location,
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{_assignment.variableNames[i]},
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make_unique<Expression>(Identifier{
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_assignment.location,
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variableReplacements.at(function->returnVariables[i].name)
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})
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});
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},
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[&](VariableDeclaration& _varDecl)
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{
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for (size_t i = 0; i < _varDecl.variables.size(); ++i)
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newStatements.emplace_back(VariableDeclaration{
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_varDecl.location,
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{std::move(_varDecl.variables[i])},
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make_unique<Expression>(Identifier{
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_varDecl.location,
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variableReplacements.at(function->returnVariables[i].name)
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})
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});
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}
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// nothing to be done for expression statement
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}, _statement);
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return newStatements;
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}
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Statement BodyCopier::operator()(VariableDeclaration const& _varDecl)
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{
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for (auto const& var: _varDecl.variables)
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m_variableReplacements[var.name] = m_nameDispenser.newName(var.name);
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return ASTCopier::operator()(_varDecl);
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}
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Statement BodyCopier::operator()(FunctionDefinition const&)
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{
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assertThrow(false, OptimizerException, "Function hoisting has to be done before function inlining.");
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return {};
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}
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YulString BodyCopier::translateIdentifier(YulString _name)
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{
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if (m_variableReplacements.count(_name))
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return m_variableReplacements.at(_name);
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else
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return _name;
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}
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