mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
351 lines
10 KiB
C++
351 lines
10 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 Federico Bond <federicobond@gmail.com>
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* @date 2016
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* Static analyzer and checker.
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*/
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#include <libsolidity/analysis/StaticAnalyzer.h>
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#include <libsolidity/analysis/ConstantEvaluator.h>
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#include <libsolidity/ast/AST.h>
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#include <liblangutil/ErrorReporter.h>
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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::langutil;
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using namespace solidity::frontend;
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/**
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* Helper class that determines whether a contract's constructor uses inline assembly.
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*/
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class solidity::frontend::ConstructorUsesAssembly
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{
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public:
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/// @returns true if and only if the contract's or any of its bases' constructors
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/// use inline assembly.
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bool check(ContractDefinition const& _contract)
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{
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for (auto const* base: _contract.annotation().linearizedBaseContracts)
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if (checkInternal(*base))
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return true;
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return false;
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}
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private:
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class Checker: public ASTConstVisitor
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{
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public:
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Checker(FunctionDefinition const& _f) { _f.accept(*this); }
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bool visit(InlineAssembly const&) override { assemblySeen = true; return false; }
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bool assemblySeen = false;
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};
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bool checkInternal(ContractDefinition const& _contract)
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{
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if (!m_usesAssembly.count(&_contract))
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{
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bool usesAssembly = false;
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if (_contract.constructor())
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usesAssembly = Checker{*_contract.constructor()}.assemblySeen;
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m_usesAssembly[&_contract] = usesAssembly;
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}
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return m_usesAssembly[&_contract];
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}
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map<ContractDefinition const*, bool> m_usesAssembly;
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};
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StaticAnalyzer::StaticAnalyzer(ErrorReporter& _errorReporter):
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m_errorReporter(_errorReporter)
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{
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}
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StaticAnalyzer::~StaticAnalyzer()
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{
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}
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bool StaticAnalyzer::analyze(SourceUnit const& _sourceUnit)
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{
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_sourceUnit.accept(*this);
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return Error::containsOnlyWarnings(m_errorReporter.errors());
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}
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bool StaticAnalyzer::visit(ContractDefinition const& _contract)
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{
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m_library = _contract.isLibrary();
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m_currentContract = &_contract;
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return true;
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}
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void StaticAnalyzer::endVisit(ContractDefinition const&)
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{
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m_library = false;
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m_currentContract = nullptr;
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}
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bool StaticAnalyzer::visit(FunctionDefinition const& _function)
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{
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if (_function.isImplemented())
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m_currentFunction = &_function;
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else
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solAssert(!m_currentFunction, "");
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solAssert(m_localVarUseCount.empty(), "");
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m_constructor = _function.isConstructor();
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return true;
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}
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void StaticAnalyzer::endVisit(FunctionDefinition const&)
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{
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if (m_currentFunction && !m_currentFunction->body().statements().empty())
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for (auto const& var: m_localVarUseCount)
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if (var.second == 0)
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{
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if (var.first.second->isCallableOrCatchParameter())
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m_errorReporter.warning(
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5667_error,
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var.first.second->location(),
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"Unused " +
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string(var.first.second->isTryCatchParameter() ? "try/catch" : "function") +
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" parameter. Remove or comment out the variable name to silence this warning."
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);
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else
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m_errorReporter.warning(2072_error, var.first.second->location(), "Unused local variable.");
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}
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m_localVarUseCount.clear();
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m_constructor = false;
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m_currentFunction = nullptr;
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}
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bool StaticAnalyzer::visit(Identifier const& _identifier)
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{
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if (m_currentFunction)
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if (auto var = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration))
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{
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solAssert(!var->name().empty(), "");
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if (var->isLocalVariable())
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m_localVarUseCount[make_pair(var->id(), var)] += 1;
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}
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return true;
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}
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bool StaticAnalyzer::visit(VariableDeclaration const& _variable)
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{
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if (m_currentFunction)
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{
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solAssert(_variable.isLocalVariable(), "");
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if (_variable.name() != "")
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// This is not a no-op, the entry might pre-exist.
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m_localVarUseCount[make_pair(_variable.id(), &_variable)] += 0;
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}
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if (_variable.isStateVariable() || _variable.referenceLocation() == VariableDeclaration::Location::Storage)
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if (auto varType = dynamic_cast<CompositeType const*>(_variable.annotation().type))
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for (Type const* type: varType->fullDecomposition())
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if (type->storageSizeUpperBound() >= (bigint(1) << 64))
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{
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string message = "Type " + type->toString(true) +
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" covers a large part of storage and thus makes collisions likely."
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" Either use mappings or dynamic arrays and allow their size to be increased only"
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" in small quantities per transaction.";
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m_errorReporter.warning(7325_error, _variable.typeName().location(), message);
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}
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return true;
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}
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bool StaticAnalyzer::visit(Return const& _return)
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{
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// If the return has an expression, it counts as
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// a "use" of the return parameters.
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if (m_currentFunction && _return.expression())
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for (auto const& var: m_currentFunction->returnParameters())
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if (!var->name().empty())
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m_localVarUseCount[make_pair(var->id(), var.get())] += 1;
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return true;
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}
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bool StaticAnalyzer::visit(ExpressionStatement const& _statement)
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{
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if (*_statement.expression().annotation().isPure)
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m_errorReporter.warning(
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6133_error,
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_statement.location(),
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"Statement has no effect."
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);
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return true;
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}
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bool StaticAnalyzer::visit(MemberAccess const& _memberAccess)
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{
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if (MagicType const* type = dynamic_cast<MagicType const*>(_memberAccess.expression().annotation().type))
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{
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if (type->kind() == MagicType::Kind::Message && _memberAccess.memberName() == "gas")
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m_errorReporter.typeError(
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1400_error,
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_memberAccess.location(),
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"\"msg.gas\" has been deprecated in favor of \"gasleft()\""
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);
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else if (type->kind() == MagicType::Kind::Block && _memberAccess.memberName() == "blockhash")
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m_errorReporter.typeError(
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8113_error,
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_memberAccess.location(),
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"\"block.blockhash()\" has been deprecated in favor of \"blockhash()\""
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);
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else if (type->kind() == MagicType::Kind::MetaType && _memberAccess.memberName() == "runtimeCode")
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{
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if (!m_constructorUsesAssembly)
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m_constructorUsesAssembly = make_unique<ConstructorUsesAssembly>();
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ContractType const& contract = dynamic_cast<ContractType const&>(*type->typeArgument());
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if (m_constructorUsesAssembly->check(contract.contractDefinition()))
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m_errorReporter.warning(
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6417_error,
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_memberAccess.location(),
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"The constructor of the contract (or its base) uses inline assembly. "
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"Because of that, it might be that the deployed bytecode is different from type(...).runtimeCode."
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);
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}
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else if (
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m_currentFunction &&
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m_currentFunction->isReceive() &&
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type->kind() == MagicType::Kind::Message &&
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_memberAccess.memberName() == "data"
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)
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m_errorReporter.typeError(
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7139_error,
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_memberAccess.location(),
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R"("msg.data" cannot be used inside of "receive" function.)"
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);
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}
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if (_memberAccess.memberName() == "callcode")
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if (auto const* type = dynamic_cast<FunctionType const*>(_memberAccess.annotation().type))
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if (type->kind() == FunctionType::Kind::BareCallCode)
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m_errorReporter.typeError(
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2256_error,
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_memberAccess.location(),
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"\"callcode\" has been deprecated in favour of \"delegatecall\"."
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);
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if (m_constructor)
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{
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auto const* expr = &_memberAccess.expression();
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while (expr)
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{
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if (auto id = dynamic_cast<Identifier const*>(expr))
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{
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if (id->name() == "this")
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m_errorReporter.warning(
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5805_error,
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id->location(),
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"\"this\" used in constructor. "
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"Note that external functions of a contract "
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"cannot be called while it is being constructed.");
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break;
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}
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else if (auto tuple = dynamic_cast<TupleExpression const*>(expr))
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{
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if (tuple->components().size() == 1)
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expr = tuple->components().front().get();
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else
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break;
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}
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else
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break;
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}
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}
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return true;
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}
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bool StaticAnalyzer::visit(InlineAssembly const& _inlineAssembly)
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{
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if (!m_currentFunction)
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return true;
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for (auto const& ref: _inlineAssembly.annotation().externalReferences)
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{
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if (auto var = dynamic_cast<VariableDeclaration const*>(ref.second.declaration))
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{
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solAssert(!var->name().empty(), "");
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if (var->isLocalVariable())
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m_localVarUseCount[make_pair(var->id(), var)] += 1;
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}
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}
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return true;
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}
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bool StaticAnalyzer::visit(BinaryOperation const& _operation)
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{
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if (
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*_operation.rightExpression().annotation().isPure &&
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(_operation.getOperator() == Token::Div || _operation.getOperator() == Token::Mod)
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)
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if (auto rhs = ConstantEvaluator::evaluate(m_errorReporter, _operation.rightExpression()))
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if (rhs->value == 0)
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m_errorReporter.typeError(
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1211_error,
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_operation.location(),
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(_operation.getOperator() == Token::Div) ? "Division by zero." : "Modulo zero."
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);
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return true;
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}
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bool StaticAnalyzer::visit(FunctionCall const& _functionCall)
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{
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if (*_functionCall.annotation().kind == FunctionCallKind::FunctionCall)
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{
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auto functionType = dynamic_cast<FunctionType const*>(_functionCall.expression().annotation().type);
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solAssert(functionType, "");
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if (functionType->kind() == FunctionType::Kind::AddMod || functionType->kind() == FunctionType::Kind::MulMod)
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{
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solAssert(_functionCall.arguments().size() == 3, "");
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if (*_functionCall.arguments()[2]->annotation().isPure)
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if (auto lastArg = ConstantEvaluator::evaluate(m_errorReporter, *(_functionCall.arguments())[2]))
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if (lastArg->value == 0)
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m_errorReporter.typeError(
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4195_error,
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_functionCall.location(),
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"Arithmetic modulo zero."
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);
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}
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if (
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m_currentContract &&
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m_currentContract->isLibrary() &&
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functionType->kind() == FunctionType::Kind::DelegateCall &&
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functionType->declaration().scope() == m_currentContract
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)
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m_errorReporter.typeError(
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6700_error,
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_functionCall.location(),
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SecondarySourceLocation().append(
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"The function declaration is here:",
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functionType->declaration().scope()->location()
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),
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"Libraries cannot call their own functions externally."
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);
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}
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return true;
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}
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