mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
125 lines
3.6 KiB
C++
125 lines
3.6 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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* @author Christian <c@ethdev.com>
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* @date 2015
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* Gas consumption estimator working alongside the AST.
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*/
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#include <libsolidity/interface/GasEstimator.h>
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#include <libsolidity/ast/AST.h>
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#include <libsolidity/ast/ASTVisitor.h>
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#include <libsolidity/codegen/CompilerUtils.h>
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#include <libevmasm/ControlFlowGraph.h>
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#include <libevmasm/KnownState.h>
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#include <libevmasm/PathGasMeter.h>
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#include <libsolutil/Keccak256.h>
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#include <functional>
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#include <map>
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#include <memory>
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using namespace std;
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using namespace solidity;
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using namespace solidity::evmasm;
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using namespace solidity::frontend;
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using namespace solidity::langutil;
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GasEstimator::GasConsumption GasEstimator::functionalEstimation(
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AssemblyItems const& _items,
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string const& _signature
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) const
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{
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auto state = make_shared<KnownState>();
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if (!_signature.empty())
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{
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ExpressionClasses& classes = state->expressionClasses();
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using Id = ExpressionClasses::Id;
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using Ids = vector<Id>;
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Id hashValue = classes.find(u256(util::FixedHash<4>::Arith(util::FixedHash<4>(util::keccak256(_signature)))));
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Id calldata = classes.find(Instruction::CALLDATALOAD, Ids{classes.find(u256(0))});
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if (!m_evmVersion.hasBitwiseShifting())
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// div(calldataload(0), 1 << 224) equals to hashValue
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classes.forceEqual(
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hashValue,
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Instruction::DIV,
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Ids{calldata, classes.find(u256(1) << 224)}
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);
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else
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// shr(0xe0, calldataload(0)) equals to hashValue
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classes.forceEqual(
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hashValue,
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Instruction::SHR,
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Ids{classes.find(u256(0xe0)), calldata}
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);
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// lt(calldatasize(), 4) equals to 0 (ignore the shortcut for fallback functions)
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classes.forceEqual(
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classes.find(u256(0)),
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Instruction::LT,
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Ids{classes.find(Instruction::CALLDATASIZE), classes.find(u256(4))}
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);
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}
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return PathGasMeter::estimateMax(_items, m_evmVersion, 0, state);
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}
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GasEstimator::GasConsumption GasEstimator::functionalEstimation(
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AssemblyItems const& _items,
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size_t const& _offset,
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FunctionDefinition const& _function
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) const
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{
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auto state = make_shared<KnownState>();
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unsigned parametersSize = CompilerUtils::sizeOnStack(_function.parameters());
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if (parametersSize > 16)
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return GasConsumption::infinite();
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// Store an invalid return value on the stack, so that the path estimator breaks upon reaching
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// the return jump.
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AssemblyItem invalidTag(PushTag, u256(-0x10));
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state->feedItem(invalidTag, true);
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if (parametersSize > 0)
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state->feedItem(swapInstruction(parametersSize));
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return PathGasMeter::estimateMax(_items, m_evmVersion, _offset, state);
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}
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set<ASTNode const*> GasEstimator::finestNodesAtLocation(
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vector<ASTNode const*> const& _roots
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)
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{
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map<SourceLocation, ASTNode const*> locations;
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set<ASTNode const*> nodes;
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SimpleASTVisitor visitor(function<bool(ASTNode const&)>(), [&](ASTNode const& _n)
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{
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if (!locations.count(_n.location()))
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{
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locations[_n.location()] = &_n;
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nodes.insert(&_n);
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}
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});
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for (ASTNode const* root: _roots)
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root->accept(visitor);
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return nodes;
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}
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