mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
149 lines
4.2 KiB
C++
149 lines
4.2 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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// SPDX-License-Identifier: GPL-3.0
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/**
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* Optimiser component that undoes what the ExpressionSplitter did, i.e.
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* it more or less inlines variable declarations.
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*/
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#include <libyul/optimiser/ExpressionJoiner.h>
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#include <libyul/optimiser/FunctionGrouper.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/Exceptions.h>
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#include <libyul/AST.h>
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#include <libsolutil/CommonData.h>
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#include <range/v3/view/reverse.hpp>
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#include <limits>
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using namespace solidity;
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using namespace solidity::yul;
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void ExpressionJoiner::run(OptimiserStepContext& _context, Block& _ast)
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{
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ExpressionJoiner{_ast}(_ast);
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FunctionGrouper::run(_context, _ast);
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}
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void ExpressionJoiner::operator()(FunctionCall& _funCall)
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{
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handleArguments(_funCall.arguments);
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}
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void ExpressionJoiner::operator()(Block& _block)
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{
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resetLatestStatementPointer();
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for (size_t i = 0; i < _block.statements.size(); ++i)
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{
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visit(_block.statements[i]);
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m_currentBlock = &_block;
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m_latestStatementInBlock = i;
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}
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removeEmptyBlocks(_block);
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resetLatestStatementPointer();
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}
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void ExpressionJoiner::visit(Expression& _e)
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{
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if (std::holds_alternative<Identifier>(_e))
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{
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Identifier const& identifier = std::get<Identifier>(_e);
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if (isLatestStatementVarDeclJoinable(identifier))
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{
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VariableDeclaration& varDecl = std::get<VariableDeclaration>(*latestStatement());
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_e = std::move(*varDecl.value);
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// Delete the variable declaration (also get the moved-from structure back into a sane state)
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*latestStatement() = Block();
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decrementLatestStatementPointer();
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}
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}
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else
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ASTModifier::visit(_e);
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}
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ExpressionJoiner::ExpressionJoiner(Block& _ast)
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{
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m_references = VariableReferencesCounter::countReferences(_ast);
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}
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void ExpressionJoiner::handleArguments(std::vector<Expression>& _arguments)
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{
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// We have to fill from left to right, but we can only
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// fill if everything to the right is just an identifier
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// or a literal.
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// Also we only descend into function calls if everything
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// on the right is an identifier or literal.
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size_t i = _arguments.size();
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for (Expression const& arg: _arguments | ranges::views::reverse)
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{
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--i;
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if (!std::holds_alternative<Identifier>(arg) && !std::holds_alternative<Literal>(arg))
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break;
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}
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// i points to the last element that is neither an identifier nor a literal,
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// or to the first element if all of them are identifiers or literals.
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for (; i < _arguments.size(); ++i)
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visit(_arguments.at(i));
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}
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void ExpressionJoiner::decrementLatestStatementPointer()
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{
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if (!m_currentBlock)
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return;
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if (m_latestStatementInBlock > 0)
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--m_latestStatementInBlock;
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else
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resetLatestStatementPointer();
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}
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void ExpressionJoiner::resetLatestStatementPointer()
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{
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m_currentBlock = nullptr;
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m_latestStatementInBlock = std::numeric_limits<size_t>::max();
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}
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Statement* ExpressionJoiner::latestStatement()
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{
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if (!m_currentBlock)
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return nullptr;
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else
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return &m_currentBlock->statements.at(m_latestStatementInBlock);
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}
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bool ExpressionJoiner::isLatestStatementVarDeclJoinable(Identifier const& _identifier)
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{
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Statement const* statement = latestStatement();
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if (!statement || !std::holds_alternative<VariableDeclaration>(*statement))
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return false;
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VariableDeclaration const& varDecl = std::get<VariableDeclaration>(*statement);
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if (varDecl.variables.size() != 1 || !varDecl.value)
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return false;
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assertThrow(varDecl.variables.size() == 1, OptimizerException, "");
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assertThrow(varDecl.value, OptimizerException, "");
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return varDecl.variables.at(0).name == _identifier.name && m_references[_identifier.name] == 1;
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}
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