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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Federico Bond <federicobond@gmail.com>
* @date 2016
* Static analyzer and checker.
*/
#include <libsolidity/analysis/StaticAnalyzer.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/interface/ErrorReporter.h>
#include <memory>
using namespace std;
using namespace dev;
using namespace dev::solidity;
bool StaticAnalyzer::analyze(SourceUnit const& _sourceUnit)
{
_sourceUnit.accept(*this);
return Error::containsOnlyWarnings(m_errorReporter.errors());
}
bool StaticAnalyzer::visit(ContractDefinition const& _contract)
{
m_library = _contract.isLibrary();
m_currentContract = &_contract;
return true;
}
void StaticAnalyzer::endVisit(ContractDefinition const&)
{
m_library = false;
m_currentContract = nullptr;
}
bool StaticAnalyzer::visit(FunctionDefinition const& _function)
{
if (_function.isImplemented())
m_currentFunction = &_function;
else
solAssert(!m_currentFunction, "");
solAssert(m_localVarUseCount.empty(), "");
m_nonPayablePublic = _function.isPublic() && !_function.isPayable();
m_constructor = _function.isConstructor();
return true;
}
void StaticAnalyzer::endVisit(FunctionDefinition const&)
{
m_currentFunction = nullptr;
m_nonPayablePublic = false;
m_constructor = false;
for (auto const& var: m_localVarUseCount)
if (var.second == 0)
{
if (var.first->isCallableParameter())
m_errorReporter.warning(
var.first->location(),
"Unused function parameter. Remove or comment out the variable name to silence this warning."
);
else
m_errorReporter.warning(var.first->location(), "Unused local variable.");
}
m_localVarUseCount.clear();
}
bool StaticAnalyzer::visit(Identifier const& _identifier)
{
if (m_currentFunction)
if (auto var = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration))
{
solAssert(!var->name().empty(), "");
if (var->isLocalVariable())
m_localVarUseCount[var] += 1;
}
return true;
}
bool StaticAnalyzer::visit(VariableDeclaration const& _variable)
{
if (m_currentFunction)
{
solAssert(_variable.isLocalVariable(), "");
if (_variable.name() != "")
// This is not a no-op, the entry might pre-exist.
m_localVarUseCount[&_variable] += 0;
}
else if (_variable.isStateVariable())
{
set<StructDefinition const*> structsSeen;
if (structureSizeEstimate(*_variable.type(), structsSeen) >= bigint(1) << 64)
m_errorReporter.warning(
_variable.location(),
"Variable covers a large part of storage and thus makes collisions likely. "
"Either use mappings or dynamic arrays and allow their size to be increased only "
"in small quantities per transaction."
);
}
return true;
}
bool StaticAnalyzer::visit(Return const& _return)
{
// If the return has an expression, it counts as
// a "use" of the return parameters.
if (m_currentFunction && _return.expression())
for (auto const& var: m_currentFunction->returnParameters())
if (!var->name().empty())
m_localVarUseCount[var.get()] += 1;
return true;
}
bool StaticAnalyzer::visit(ExpressionStatement const& _statement)
{
if (_statement.expression().annotation().isPure)
m_errorReporter.warning(
_statement.location(),
"Statement has no effect."
);
return true;
}
bool StaticAnalyzer::visit(MemberAccess const& _memberAccess)
{
bool const v050 = m_currentContract->sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::V050);
if (MagicType const* type = dynamic_cast<MagicType const*>(_memberAccess.expression().annotation().type.get()))
{
if (type->kind() == MagicType::Kind::Message && _memberAccess.memberName() == "gas")
{
if (v050)
m_errorReporter.typeError(
_memberAccess.location(),
"\"msg.gas\" has been deprecated in favor of \"gasleft()\""
);
else
m_errorReporter.warning(
_memberAccess.location(),
"\"msg.gas\" has been deprecated in favor of \"gasleft()\""
);
}
if (type->kind() == MagicType::Kind::Block && _memberAccess.memberName() == "blockhash")
{
if (v050)
m_errorReporter.typeError(
_memberAccess.location(),
"\"block.blockhash()\" has been deprecated in favor of \"blockhash()\""
);
else
m_errorReporter.warning(
_memberAccess.location(),
"\"block.blockhash()\" has been deprecated in favor of \"blockhash()\""
);
}
}
if (m_nonPayablePublic && !m_library)
if (MagicType const* type = dynamic_cast<MagicType const*>(_memberAccess.expression().annotation().type.get()))
if (type->kind() == MagicType::Kind::Message && _memberAccess.memberName() == "value")
m_errorReporter.warning(
_memberAccess.location(),
"\"msg.value\" used in non-payable function. Do you want to add the \"payable\" modifier to this function?"
);
if (_memberAccess.memberName() == "callcode")
if (auto const* type = dynamic_cast<FunctionType const*>(_memberAccess.annotation().type.get()))
if (type->kind() == FunctionType::Kind::BareCallCode)
{
if (v050)
m_errorReporter.typeError(
_memberAccess.location(),
"\"callcode\" has been deprecated in favour of \"delegatecall\"."
);
else
m_errorReporter.warning(
_memberAccess.location(),
"\"callcode\" has been deprecated in favour of \"delegatecall\"."
);
}
if (m_constructor && m_currentContract)
if (ContractType const* type = dynamic_cast<ContractType const*>(_memberAccess.expression().annotation().type.get()))
if (type->contractDefinition() == *m_currentContract)
m_errorReporter.warning(_memberAccess.location(), "\"this\" used in constructor.");
return true;
}
bool StaticAnalyzer::visit(InlineAssembly const& _inlineAssembly)
{
if (!m_currentFunction)
return true;
for (auto const& ref: _inlineAssembly.annotation().externalReferences)
{
if (auto var = dynamic_cast<VariableDeclaration const*>(ref.second.declaration))
{
solAssert(!var->name().empty(), "");
if (var->isLocalVariable())
m_localVarUseCount[var] += 1;
}
}
return true;
}
bigint StaticAnalyzer::structureSizeEstimate(Type const& _type, set<StructDefinition const*>& _structsSeen)
{
switch (_type.category())
{
case Type::Category::Array:
{
auto const& t = dynamic_cast<ArrayType const&>(_type);
return structureSizeEstimate(*t.baseType(), _structsSeen) * (t.isDynamicallySized() ? 1 : t.length());
}
case Type::Category::Struct:
{
auto const& t = dynamic_cast<StructType const&>(_type);
bigint size = 1;
if (!_structsSeen.count(&t.structDefinition()))
{
_structsSeen.insert(&t.structDefinition());
for (auto const& m: t.members(nullptr))
size += structureSizeEstimate(*m.type, _structsSeen);
}
return size;
}
case Type::Category::Mapping:
{
return structureSizeEstimate(*dynamic_cast<MappingType const&>(_type).valueType(), _structsSeen);
}
default:
break;
}
return bigint(1);
}
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