solidity/libsolidity/formal/SMTChecker.cpp
chriseth 89700dbcff
Merge pull request #6665 from ethereum/smt_inline_external_this
[SMTChecker] Inline external function calls to `this`
2019-05-09 19:09:08 +02:00

2006 lines
60 KiB
C++

/*
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/>.
*/
#include <libsolidity/formal/SMTChecker.h>
#include <libsolidity/ast/TypeProvider.h>
#include <libsolidity/formal/SMTPortfolio.h>
#include <libsolidity/formal/SymbolicTypes.h>
#include <libdevcore/StringUtils.h>
#include <boost/range/adaptor/map.hpp>
#include <boost/range/adaptors.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/optional.hpp>
using namespace std;
using namespace dev;
using namespace langutil;
using namespace dev::solidity;
SMTChecker::SMTChecker(ErrorReporter& _errorReporter, map<h256, string> const& _smtlib2Responses):
m_interface(make_shared<smt::SMTPortfolio>(_smtlib2Responses)),
m_errorReporterReference(_errorReporter),
m_errorReporter(m_smtErrors),
m_context(*m_interface)
{
#if defined (HAVE_Z3) || defined (HAVE_CVC4)
if (!_smtlib2Responses.empty())
m_errorReporter.warning(
"SMT-LIB2 query responses were given in the auxiliary input, "
"but this Solidity binary uses an SMT solver (Z3/CVC4) directly."
"These responses will be ignored."
"Consider disabling Z3/CVC4 at compilation time in order to use SMT-LIB2 responses."
);
#endif
}
void SMTChecker::analyze(SourceUnit const& _source, shared_ptr<Scanner> const& _scanner)
{
m_scanner = _scanner;
if (_source.annotation().experimentalFeatures.count(ExperimentalFeature::SMTChecker))
_source.accept(*this);
solAssert(m_interface->solvers() > 0, "");
// If this check is true, Z3 and CVC4 are not available
// and the query answers were not provided, since SMTPortfolio
// guarantees that SmtLib2Interface is the first solver.
if (!m_interface->unhandledQueries().empty() && m_interface->solvers() == 1)
{
if (!m_noSolverWarning)
{
m_noSolverWarning = true;
m_errorReporterReference.warning(
SourceLocation(),
"SMTChecker analysis was not possible since no integrated SMT solver (Z3 or CVC4) was found."
);
}
}
else
m_errorReporterReference.append(m_errorReporter.errors());
m_errorReporter.clear();
}
bool SMTChecker::visit(ContractDefinition const& _contract)
{
for (auto const& contract: _contract.annotation().linearizedBaseContracts)
for (auto var : contract->stateVariables())
if (*contract == _contract || var->isVisibleInDerivedContracts())
createVariable(*var);
return true;
}
void SMTChecker::endVisit(ContractDefinition const&)
{
m_variables.clear();
}
void SMTChecker::endVisit(VariableDeclaration const& _varDecl)
{
if (_varDecl.isLocalVariable() && _varDecl.type()->isValueType() &&_varDecl.value())
assignment(_varDecl, *_varDecl.value(), _varDecl.location());
}
bool SMTChecker::visit(ModifierDefinition const&)
{
return false;
}
bool SMTChecker::visit(FunctionDefinition const& _function)
{
// Not visited by a function call
if (m_callStack.empty())
{
m_interface->reset();
m_context.reset();
m_pathConditions.clear();
m_callStack.clear();
pushCallStack({&_function, nullptr});
m_expressions.clear();
m_globalContext.clear();
m_uninterpretedTerms.clear();
m_overflowTargets.clear();
resetStateVariables();
initializeLocalVariables(_function);
m_loopExecutionHappened = false;
m_arrayAssignmentHappened = false;
m_externalFunctionCallHappened = false;
}
m_modifierDepthStack.push_back(-1);
if (_function.isConstructor())
{
m_errorReporter.warning(
_function.location(),
"Assertion checker does not yet support constructors."
);
}
else
{
_function.parameterList().accept(*this);
if (_function.returnParameterList())
_function.returnParameterList()->accept(*this);
visitFunctionOrModifier();
}
return false;
}
void SMTChecker::visitFunctionOrModifier()
{
solAssert(!m_callStack.empty(), "");
solAssert(!m_modifierDepthStack.empty(), "");
++m_modifierDepthStack.back();
FunctionDefinition const& function = dynamic_cast<FunctionDefinition const&>(*m_callStack.back().first);
if (m_modifierDepthStack.back() == int(function.modifiers().size()))
{
if (function.isImplemented())
function.body().accept(*this);
}
else
{
solAssert(m_modifierDepthStack.back() < int(function.modifiers().size()), "");
ASTPointer<ModifierInvocation> const& modifierInvocation = function.modifiers()[m_modifierDepthStack.back()];
solAssert(modifierInvocation, "");
modifierInvocation->accept(*this);
auto const& modifierDef = dynamic_cast<ModifierDefinition const&>(
*modifierInvocation->name()->annotation().referencedDeclaration
);
vector<smt::Expression> modifierArgsExpr;
if (modifierInvocation->arguments())
for (auto arg: *modifierInvocation->arguments())
modifierArgsExpr.push_back(expr(*arg));
initializeFunctionCallParameters(modifierDef, modifierArgsExpr);
pushCallStack({&modifierDef, modifierInvocation.get()});
modifierDef.body().accept(*this);
popCallStack();
}
--m_modifierDepthStack.back();
}
bool SMTChecker::visit(PlaceholderStatement const&)
{
solAssert(!m_callStack.empty(), "");
auto lastCall = popCallStack();
visitFunctionOrModifier();
pushCallStack(lastCall);
return true;
}
void SMTChecker::endVisit(FunctionDefinition const&)
{
m_callStack.pop_back();
solAssert(m_modifierDepthStack.back() == -1, "");
m_modifierDepthStack.pop_back();
// If _function was visited from a function call we don't remove
// the local variables just yet, since we might need them for
// future calls.
// Otherwise we remove any local variables from the context and
// keep the state variables.
if (m_callStack.empty())
{
checkUnderOverflow();
solAssert(m_callStack.empty(), "");
}
}
bool SMTChecker::visit(InlineAssembly const& _inlineAsm)
{
m_errorReporter.warning(
_inlineAsm.location(),
"Assertion checker does not support inline assembly."
);
return false;
}
bool SMTChecker::visit(IfStatement const& _node)
{
_node.condition().accept(*this);
// We ignore called functions here because they have
// specific input values.
if (isRootFunction())
checkBooleanNotConstant(_node.condition(), "Condition is always $VALUE.");
auto indicesEndTrue = visitBranch(&_node.trueStatement(), expr(_node.condition()));
auto touchedVars = touchedVariables(_node.trueStatement());
decltype(indicesEndTrue) indicesEndFalse;
if (_node.falseStatement())
{
indicesEndFalse = visitBranch(_node.falseStatement(), !expr(_node.condition()));
touchedVars += touchedVariables(*_node.falseStatement());
}
else
indicesEndFalse = copyVariableIndices();
mergeVariables(touchedVars, expr(_node.condition()), indicesEndTrue, indicesEndFalse);
return false;
}
// Here we consider the execution of two branches:
// Branch 1 assumes the loop condition to be true and executes the loop once,
// after resetting touched variables.
// Branch 2 assumes the loop condition to be false and skips the loop after
// visiting the condition (it might contain side-effects, they need to be considered)
// and does not erase knowledge.
// If the loop is a do-while, condition side-effects are lost since the body,
// executed once before the condition, might reassign variables.
// Variables touched by the loop are merged with Branch 2.
bool SMTChecker::visit(WhileStatement const& _node)
{
auto indicesBeforeLoop = copyVariableIndices();
auto touchedVars = touchedVariables(_node);
resetVariables(touchedVars);
decltype(indicesBeforeLoop) indicesAfterLoop;
if (_node.isDoWhile())
{
indicesAfterLoop = visitBranch(&_node.body());
// TODO the assertions generated in the body should still be active in the condition
_node.condition().accept(*this);
if (isRootFunction())
checkBooleanNotConstant(_node.condition(), "Do-while loop condition is always $VALUE.");
}
else
{
_node.condition().accept(*this);
if (isRootFunction())
checkBooleanNotConstant(_node.condition(), "While loop condition is always $VALUE.");
indicesAfterLoop = visitBranch(&_node.body(), expr(_node.condition()));
}
// We reset the execution to before the loop
// and visit the condition in case it's not a do-while.
// A do-while's body might have non-precise information
// in its first run about variables that are touched.
resetVariableIndices(indicesBeforeLoop);
if (!_node.isDoWhile())
_node.condition().accept(*this);
mergeVariables(touchedVars, expr(_node.condition()), indicesAfterLoop, copyVariableIndices());
m_loopExecutionHappened = true;
return false;
}
// Here we consider the execution of two branches similar to WhileStatement.
bool SMTChecker::visit(ForStatement const& _node)
{
if (_node.initializationExpression())
_node.initializationExpression()->accept(*this);
auto indicesBeforeLoop = copyVariableIndices();
// Do not reset the init expression part.
auto touchedVars = touchedVariables(_node.body());
if (_node.condition())
touchedVars += touchedVariables(*_node.condition());
if (_node.loopExpression())
touchedVars += touchedVariables(*_node.loopExpression());
resetVariables(touchedVars);
if (_node.condition())
{
_node.condition()->accept(*this);
if (isRootFunction())
checkBooleanNotConstant(*_node.condition(), "For loop condition is always $VALUE.");
}
m_interface->push();
if (_node.condition())
m_interface->addAssertion(expr(*_node.condition()));
_node.body().accept(*this);
if (_node.loopExpression())
_node.loopExpression()->accept(*this);
m_interface->pop();
auto indicesAfterLoop = copyVariableIndices();
// We reset the execution to before the loop
// and visit the condition.
resetVariableIndices(indicesBeforeLoop);
if (_node.condition())
_node.condition()->accept(*this);
auto forCondition = _node.condition() ? expr(*_node.condition()) : smt::Expression(true);
mergeVariables(touchedVars, forCondition, indicesAfterLoop, copyVariableIndices());
m_loopExecutionHappened = true;
return false;
}
void SMTChecker::endVisit(VariableDeclarationStatement const& _varDecl)
{
if (_varDecl.declarations().size() != 1)
{
if (auto init = _varDecl.initialValue())
{
auto symbTuple = dynamic_pointer_cast<SymbolicTupleVariable>(m_expressions[init]);
/// symbTuple == nullptr if it is the return of a non-inlined function call.
if (symbTuple)
{
auto const& components = symbTuple->components();
auto const& declarations = _varDecl.declarations();
for (unsigned i = 0; i < declarations.size(); ++i)
{
solAssert(components.at(i), "");
if (declarations.at(i) && knownVariable(*declarations.at(i)))
assignment(*declarations.at(i), components.at(i)->currentValue(), declarations.at(i)->location());
}
}
}
}
else if (knownVariable(*_varDecl.declarations().front()))
{
if (_varDecl.initialValue())
assignment(*_varDecl.declarations().front(), *_varDecl.initialValue(), _varDecl.location());
}
else
m_errorReporter.warning(
_varDecl.location(),
"Assertion checker does not yet implement such variable declarations."
);
}
void SMTChecker::endVisit(Assignment const& _assignment)
{
static set<Token> const compoundOps{
Token::AssignAdd,
Token::AssignSub,
Token::AssignMul,
Token::AssignDiv,
Token::AssignMod
};
Token op = _assignment.assignmentOperator();
if (op != Token::Assign && !compoundOps.count(op))
m_errorReporter.warning(
_assignment.location(),
"Assertion checker does not yet implement this assignment operator."
);
else if (!isSupportedType(_assignment.annotation().type->category()))
{
m_errorReporter.warning(
_assignment.location(),
"Assertion checker does not yet implement type " + _assignment.annotation().type->toString()
);
// Give it a new index anyway to keep the SSA scheme sound.
if (auto varDecl = identifierToVariable(_assignment.leftHandSide()))
newValue(*varDecl);
}
else
{
vector<smt::Expression> rightArguments;
if (_assignment.rightHandSide().annotation().type->category() == Type::Category::Tuple)
{
auto symbTuple = dynamic_pointer_cast<SymbolicTupleVariable>(m_expressions[&_assignment.rightHandSide()]);
solAssert(symbTuple, "");
for (auto const& component: symbTuple->components())
{
/// Right hand side tuple component cannot be empty.
solAssert(component, "");
rightArguments.push_back(component->currentValue());
}
}
else
{
auto rightHandSide = compoundOps.count(op) ?
compoundAssignment(_assignment) :
expr(_assignment.rightHandSide());
defineExpr(_assignment, rightHandSide);
rightArguments.push_back(expr(_assignment));
}
assignment(
_assignment.leftHandSide(),
rightArguments,
_assignment.annotation().type,
_assignment.location()
);
}
}
void SMTChecker::endVisit(TupleExpression const& _tuple)
{
if (_tuple.isInlineArray())
m_errorReporter.warning(
_tuple.location(),
"Assertion checker does not yet implement inline arrays."
);
else if (_tuple.annotation().type->category() == Type::Category::Tuple)
{
createExpr(_tuple);
vector<shared_ptr<SymbolicVariable>> components;
for (auto const& component: _tuple.components())
if (component)
{
if (auto varDecl = identifierToVariable(*component))
components.push_back(m_variables[varDecl]);
else
{
solAssert(knownExpr(*component), "");
components.push_back(m_expressions[component.get()]);
}
}
else
components.push_back(nullptr);
solAssert(components.size() == _tuple.components().size(), "");
auto const& symbTuple = dynamic_pointer_cast<SymbolicTupleVariable>(m_expressions[&_tuple]);
solAssert(symbTuple, "");
symbTuple->setComponents(move(components));
}
else
{
/// Parenthesized expressions are also TupleExpression regardless their type.
auto const& components = _tuple.components();
solAssert(components.size() == 1, "");
if (isSupportedType(components.front()->annotation().type->category()))
defineExpr(_tuple, expr(*components.front()));
}
}
void SMTChecker::addOverflowTarget(
OverflowTarget::Type _type,
TypePointer _intType,
smt::Expression _value,
SourceLocation const& _location
)
{
m_overflowTargets.emplace_back(
_type,
std::move(_intType),
std::move(_value),
currentPathConditions(),
_location,
m_callStack
);
}
void SMTChecker::checkUnderOverflow()
{
for (auto& target: m_overflowTargets)
{
swap(m_callStack, target.callStack);
if (target.type != OverflowTarget::Type::Overflow)
checkUnderflow(target);
if (target.type != OverflowTarget::Type::Underflow)
checkOverflow(target);
swap(m_callStack, target.callStack);
}
}
void SMTChecker::checkUnderflow(OverflowTarget& _target)
{
solAssert(_target.type != OverflowTarget::Type::Overflow, "");
auto intType = dynamic_cast<IntegerType const*>(_target.intType);
checkCondition(
_target.path && _target.value < minValue(*intType),
_target.location,
"Underflow (resulting value less than " + formatNumberReadable(intType->minValue()) + ")",
"<result>",
&_target.value
);
}
void SMTChecker::checkOverflow(OverflowTarget& _target)
{
solAssert(_target.type != OverflowTarget::Type::Underflow, "");
auto intType = dynamic_cast<IntegerType const*>(_target.intType);
checkCondition(
_target.path && _target.value > maxValue(*intType),
_target.location,
"Overflow (resulting value larger than " + formatNumberReadable(intType->maxValue()) + ")",
"<result>",
&_target.value
);
}
void SMTChecker::endVisit(UnaryOperation const& _op)
{
if (_op.annotation().type->category() == Type::Category::RationalNumber)
return;
switch (_op.getOperator())
{
case Token::Not: // !
{
solAssert(isBool(_op.annotation().type->category()), "");
defineExpr(_op, !expr(_op.subExpression()));
break;
}
case Token::Inc: // ++ (pre- or postfix)
case Token::Dec: // -- (pre- or postfix)
{
solAssert(isInteger(_op.annotation().type->category()), "");
solAssert(_op.subExpression().annotation().lValueRequested, "");
if (auto identifier = dynamic_cast<Identifier const*>(&_op.subExpression()))
{
auto decl = identifierToVariable(*identifier);
solAssert(decl, "");
auto innerValue = currentValue(*decl);
auto newValue = _op.getOperator() == Token::Inc ? innerValue + 1 : innerValue - 1;
defineExpr(_op, _op.isPrefixOperation() ? newValue : innerValue);
assignment(*decl, newValue, _op.location());
}
else if (dynamic_cast<IndexAccess const*>(&_op.subExpression()))
{
auto innerValue = expr(_op.subExpression());
auto newValue = _op.getOperator() == Token::Inc ? innerValue + 1 : innerValue - 1;
defineExpr(_op, _op.isPrefixOperation() ? newValue : innerValue);
arrayIndexAssignment(_op.subExpression(), newValue);
}
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement such increments / decrements."
);
break;
}
case Token::Sub: // -
{
defineExpr(_op, 0 - expr(_op.subExpression()));
if (_op.annotation().type->category() == Type::Category::Integer)
addOverflowTarget(
OverflowTarget::Type::All,
_op.annotation().type,
expr(_op),
_op.location()
);
break;
}
case Token::Delete:
{
auto const& subExpr = _op.subExpression();
if (auto decl = identifierToVariable(subExpr))
{
newValue(*decl);
setZeroValue(*decl);
}
else
{
solAssert(knownExpr(subExpr), "");
auto const& symbVar = m_expressions[&subExpr];
symbVar->increaseIndex();
setZeroValue(*symbVar);
if (dynamic_cast<IndexAccess const*>(&_op.subExpression()))
arrayIndexAssignment(_op.subExpression(), symbVar->currentValue());
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement \"delete\" for this expression."
);
}
break;
}
default:
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement this operator."
);
}
}
bool SMTChecker::visit(UnaryOperation const& _op)
{
return !shortcutRationalNumber(_op);
}
bool SMTChecker::visit(BinaryOperation const& _op)
{
if (shortcutRationalNumber(_op))
return false;
if (TokenTraits::isBooleanOp(_op.getOperator()))
{
booleanOperation(_op);
return false;
}
return true;
}
void SMTChecker::endVisit(BinaryOperation const& _op)
{
if (_op.annotation().type->category() == Type::Category::RationalNumber)
return;
if (TokenTraits::isBooleanOp(_op.getOperator()))
return;
if (TokenTraits::isArithmeticOp(_op.getOperator()))
arithmeticOperation(_op);
else if (TokenTraits::isCompareOp(_op.getOperator()))
compareOperation(_op);
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement this operator."
);
}
void SMTChecker::endVisit(FunctionCall const& _funCall)
{
solAssert(_funCall.annotation().kind != FunctionCallKind::Unset, "");
if (_funCall.annotation().kind == FunctionCallKind::StructConstructorCall)
{
m_errorReporter.warning(
_funCall.location(),
"Assertion checker does not yet implement this expression."
);
return;
}
if (_funCall.annotation().kind == FunctionCallKind::TypeConversion)
{
visitTypeConversion(_funCall);
return;
}
FunctionType const& funType = dynamic_cast<FunctionType const&>(*_funCall.expression().annotation().type);
std::vector<ASTPointer<Expression const>> const args = _funCall.arguments();
switch (funType.kind())
{
case FunctionType::Kind::Assert:
visitAssert(_funCall);
break;
case FunctionType::Kind::Require:
visitRequire(_funCall);
break;
case FunctionType::Kind::GasLeft:
visitGasLeft(_funCall);
break;
case FunctionType::Kind::Internal:
case FunctionType::Kind::External:
case FunctionType::Kind::DelegateCall:
case FunctionType::Kind::BareCall:
case FunctionType::Kind::BareCallCode:
case FunctionType::Kind::BareDelegateCall:
case FunctionType::Kind::BareStaticCall:
case FunctionType::Kind::Creation:
internalOrExternalFunctionCall(_funCall);
break;
case FunctionType::Kind::KECCAK256:
case FunctionType::Kind::ECRecover:
case FunctionType::Kind::SHA256:
case FunctionType::Kind::RIPEMD160:
case FunctionType::Kind::BlockHash:
case FunctionType::Kind::AddMod:
case FunctionType::Kind::MulMod:
abstractFunctionCall(_funCall);
break;
case FunctionType::Kind::Send:
case FunctionType::Kind::Transfer:
{
auto const& memberAccess = dynamic_cast<MemberAccess const&>(_funCall.expression());
auto const& address = memberAccess.expression();
auto const& value = args.at(0);
solAssert(value, "");
smt::Expression thisBalance = m_context.balance();
setSymbolicUnknownValue(thisBalance, TypeProvider::uint256(), *m_interface);
checkCondition(thisBalance < expr(*value), _funCall.location(), "Insufficient funds", "address(this).balance", &thisBalance);
m_context.transfer(m_context.thisAddress(), expr(address), expr(*value));
createExpr(_funCall);
break;
}
default:
m_errorReporter.warning(
_funCall.location(),
"Assertion checker does not yet implement this type of function call."
);
}
}
void SMTChecker::visitAssert(FunctionCall const& _funCall)
{
auto const& args = _funCall.arguments();
solAssert(args.size() == 1, "");
solAssert(args[0]->annotation().type->category() == Type::Category::Bool, "");
checkCondition(!(expr(*args[0])), _funCall.location(), "Assertion violation");
addPathImpliedExpression(expr(*args[0]));
}
void SMTChecker::visitRequire(FunctionCall const& _funCall)
{
auto const& args = _funCall.arguments();
solAssert(args.size() == 1, "");
solAssert(args[0]->annotation().type->category() == Type::Category::Bool, "");
if (isRootFunction())
checkBooleanNotConstant(*args[0], "Condition is always $VALUE.");
addPathImpliedExpression(expr(*args[0]));
}
void SMTChecker::visitGasLeft(FunctionCall const& _funCall)
{
string gasLeft = "gasleft()";
// We increase the variable index since gasleft changes
// inside a tx.
defineGlobalVariable(gasLeft, _funCall, true);
auto const& symbolicVar = m_globalContext.at(gasLeft);
unsigned index = symbolicVar->index();
// We set the current value to unknown anyway to add type constraints.
setUnknownValue(*symbolicVar);
if (index > 0)
m_interface->addAssertion(symbolicVar->currentValue() <= symbolicVar->valueAtIndex(index - 1));
}
void SMTChecker::inlineFunctionCall(FunctionCall const& _funCall)
{
FunctionDefinition const* funDef = inlinedFunctionCallToDefinition(_funCall);
if (!funDef)
{
m_errorReporter.warning(
_funCall.location(),
"Assertion checker does not yet implement this type of function call."
);
}
else if (visitedFunction(funDef))
m_errorReporter.warning(
_funCall.location(),
"Assertion checker does not support recursive function calls.",
SecondarySourceLocation().append("Starting from function:", funDef->location())
);
else
{
vector<smt::Expression> funArgs;
Expression const* calledExpr = &_funCall.expression();
auto const& funType = dynamic_cast<FunctionType const*>(calledExpr->annotation().type);
solAssert(funType, "");
if (funType->bound())
{
auto const& boundFunction = dynamic_cast<MemberAccess const*>(calledExpr);
solAssert(boundFunction, "");
funArgs.push_back(expr(boundFunction->expression()));
}
for (auto arg: _funCall.arguments())
funArgs.push_back(expr(*arg));
initializeFunctionCallParameters(*funDef, funArgs);
// The reason why we need to pushCallStack here instead of visit(FunctionDefinition)
// is that there we don't have `_funCall`.
pushCallStack({funDef, &_funCall});
funDef->accept(*this);
// The callstack entry is popped only in endVisit(FunctionDefinition) instead of here
// as well to avoid code duplication (not all entries are from inlined function calls).
createExpr(_funCall);
auto const& returnParams = funDef->returnParameters();
if (returnParams.size() > 1)
{
vector<shared_ptr<SymbolicVariable>> components;
for (auto param: returnParams)
{
solAssert(m_variables[param.get()], "");
components.push_back(m_variables[param.get()]);
}
auto const& symbTuple = dynamic_pointer_cast<SymbolicTupleVariable>(m_expressions[&_funCall]);
solAssert(symbTuple, "");
symbTuple->setComponents(move(components));
}
else if (returnParams.size() == 1)
defineExpr(_funCall, currentValue(*returnParams.front()));
}
}
void SMTChecker::internalOrExternalFunctionCall(FunctionCall const& _funCall)
{
auto funDef = inlinedFunctionCallToDefinition(_funCall);
auto const& funType = dynamic_cast<FunctionType const&>(*_funCall.expression().annotation().type);
if (funDef)
inlineFunctionCall(_funCall);
else if (funType.kind() == FunctionType::Kind::Internal)
m_errorReporter.warning(
_funCall.location(),
"Assertion checker does not yet implement this type of function call."
);
else
{
m_externalFunctionCallHappened = true;
resetStateVariables();
resetStorageReferences();
}
}
void SMTChecker::abstractFunctionCall(FunctionCall const& _funCall)
{
vector<smt::Expression> smtArguments;
for (auto const& arg: _funCall.arguments())
smtArguments.push_back(expr(*arg));
defineExpr(_funCall, (*m_expressions.at(&_funCall.expression()))(smtArguments));
m_uninterpretedTerms.insert(&_funCall);
setSymbolicUnknownValue(expr(_funCall), _funCall.annotation().type, *m_interface);
}
void SMTChecker::endVisit(Identifier const& _identifier)
{
if (_identifier.annotation().lValueRequested)
{
// Will be translated as part of the node that requested the lvalue.
}
else if (_identifier.annotation().type->category() == Type::Category::Function)
visitFunctionIdentifier(_identifier);
else if (isSupportedType(_identifier.annotation().type->category()))
{
if (auto decl = identifierToVariable(_identifier))
defineExpr(_identifier, currentValue(*decl));
else if (_identifier.name() == "now")
defineGlobalVariable(_identifier.name(), _identifier);
else if (_identifier.name() == "this")
{
defineExpr(_identifier, m_context.thisAddress());
m_uninterpretedTerms.insert(&_identifier);
}
else
// TODO: handle MagicVariableDeclaration here
m_errorReporter.warning(
_identifier.location(),
"Assertion checker does not yet support the type of this variable."
);
}
}
void SMTChecker::visitTypeConversion(FunctionCall const& _funCall)
{
solAssert(_funCall.annotation().kind == FunctionCallKind::TypeConversion, "");
solAssert(_funCall.arguments().size() == 1, "");
auto argument = _funCall.arguments().at(0);
unsigned argSize = argument->annotation().type->storageBytes();
unsigned castSize = _funCall.annotation().type->storageBytes();
if (argSize == castSize)
defineExpr(_funCall, expr(*argument));
else
{
createExpr(_funCall);
setUnknownValue(*m_expressions.at(&_funCall));
auto const& funCallCategory = _funCall.annotation().type->category();
// TODO: truncating and bytesX needs a different approach because of right padding.
if (funCallCategory == Type::Category::Integer || funCallCategory == Type::Category::Address)
{
if (argSize < castSize)
defineExpr(_funCall, expr(*argument));
else
{
auto const& intType = dynamic_cast<IntegerType const&>(*m_expressions.at(&_funCall)->type());
defineExpr(_funCall, smt::Expression::ite(
expr(*argument) >= minValue(intType) && expr(*argument) <= maxValue(intType),
expr(*argument),
expr(_funCall)
));
}
}
m_errorReporter.warning(
_funCall.location(),
"Type conversion is not yet fully supported and might yield false positives."
);
}
}
void SMTChecker::visitFunctionIdentifier(Identifier const& _identifier)
{
auto const& fType = dynamic_cast<FunctionType const&>(*_identifier.annotation().type);
if (fType.returnParameterTypes().size() == 1)
{
defineGlobalFunction(fType.richIdentifier(), _identifier);
m_expressions.emplace(&_identifier, m_globalContext.at(fType.richIdentifier()));
}
}
void SMTChecker::endVisit(Literal const& _literal)
{
solAssert(_literal.annotation().type, "Expected type for AST node");
Type const& type = *_literal.annotation().type;
if (isNumber(type.category()))
defineExpr(_literal, smt::Expression(type.literalValue(&_literal)));
else if (isBool(type.category()))
defineExpr(_literal, smt::Expression(_literal.token() == Token::TrueLiteral ? true : false));
else
{
if (type.category() == Type::Category::StringLiteral)
{
auto stringType = TypeProvider::stringMemory();
auto stringLit = dynamic_cast<StringLiteralType const*>(_literal.annotation().type);
solAssert(stringLit, "");
auto result = newSymbolicVariable(*stringType, stringLit->richIdentifier(), *m_interface);
m_expressions.emplace(&_literal, result.second);
}
m_errorReporter.warning(
_literal.location(),
"Assertion checker does not yet support the type of this literal (" +
_literal.annotation().type->toString() +
")."
);
}
}
void SMTChecker::endVisit(Return const& _return)
{
if (_return.expression() && knownExpr(*_return.expression()))
{
auto returnParams = m_callStack.back().first->returnParameters();
if (returnParams.size() > 1)
{
auto tuple = dynamic_cast<TupleExpression const*>(_return.expression());
solAssert(tuple, "");
auto const& components = tuple->components();
solAssert(components.size() == returnParams.size(), "");
for (unsigned i = 0; i < returnParams.size(); ++i)
if (components.at(i))
m_interface->addAssertion(expr(*components.at(i)) == newValue(*returnParams.at(i)));
}
else if (returnParams.size() == 1)
m_interface->addAssertion(expr(*_return.expression()) == newValue(*returnParams.front()));
}
}
bool SMTChecker::visit(MemberAccess const& _memberAccess)
{
auto const& accessType = _memberAccess.annotation().type;
if (accessType->category() == Type::Category::Function)
return true;
auto const& exprType = _memberAccess.expression().annotation().type;
solAssert(exprType, "");
auto identifier = dynamic_cast<Identifier const*>(&_memberAccess.expression());
if (exprType->category() == Type::Category::Magic)
{
string accessedName;
if (identifier)
accessedName = identifier->name();
else
m_errorReporter.warning(
_memberAccess.location(),
"Assertion checker does not yet support this expression."
);
defineGlobalVariable(accessedName + "." + _memberAccess.memberName(), _memberAccess);
return false;
}
else if (exprType->category() == Type::Category::TypeType)
{
if (identifier && dynamic_cast<EnumDefinition const*>(identifier->annotation().referencedDeclaration))
{
auto enumType = dynamic_cast<EnumType const*>(accessType);
solAssert(enumType, "");
defineExpr(_memberAccess, enumType->memberValue(_memberAccess.memberName()));
}
return false;
}
else if (exprType->category() == Type::Category::Address)
{
_memberAccess.expression().accept(*this);
if (_memberAccess.memberName() == "balance")
{
defineExpr(_memberAccess, m_context.balance(expr(_memberAccess.expression())));
setSymbolicUnknownValue(*m_expressions[&_memberAccess], *m_interface);
m_uninterpretedTerms.insert(&_memberAccess);
return false;
}
}
else
m_errorReporter.warning(
_memberAccess.location(),
"Assertion checker does not yet support this expression."
);
createExpr(_memberAccess);
return true;
}
void SMTChecker::endVisit(IndexAccess const& _indexAccess)
{
shared_ptr<SymbolicVariable> array;
if (auto const& id = dynamic_cast<Identifier const*>(&_indexAccess.baseExpression()))
{
auto varDecl = identifierToVariable(*id);
solAssert(varDecl, "");
array = m_variables[varDecl];
}
else if (auto const& innerAccess = dynamic_cast<IndexAccess const*>(&_indexAccess.baseExpression()))
{
solAssert(knownExpr(*innerAccess), "");
array = m_expressions[innerAccess];
}
else
{
m_errorReporter.warning(
_indexAccess.location(),
"Assertion checker does not yet implement this expression."
);
return;
}
solAssert(array, "");
defineExpr(_indexAccess, smt::Expression::select(
array->currentValue(),
expr(*_indexAccess.indexExpression())
));
setSymbolicUnknownValue(
expr(_indexAccess),
_indexAccess.annotation().type,
*m_interface
);
m_uninterpretedTerms.insert(&_indexAccess);
}
void SMTChecker::arrayAssignment()
{
m_arrayAssignmentHappened = true;
}
void SMTChecker::arrayIndexAssignment(Expression const& _expr, smt::Expression const& _rightHandSide)
{
auto const& indexAccess = dynamic_cast<IndexAccess const&>(_expr);
if (auto const& id = dynamic_cast<Identifier const*>(&indexAccess.baseExpression()))
{
auto varDecl = identifierToVariable(*id);
solAssert(varDecl, "");
if (varDecl->hasReferenceOrMappingType())
resetVariables([&](VariableDeclaration const& _var) {
if (_var == *varDecl)
return false;
TypePointer prefix = _var.type();
TypePointer originalType = typeWithoutPointer(varDecl->type());
while (
prefix->category() == Type::Category::Mapping ||
prefix->category() == Type::Category::Array
)
{
if (*originalType == *typeWithoutPointer(prefix))
return true;
if (prefix->category() == Type::Category::Mapping)
{
auto mapPrefix = dynamic_cast<MappingType const*>(prefix);
solAssert(mapPrefix, "");
prefix = mapPrefix->valueType();
}
else
{
auto arrayPrefix = dynamic_cast<ArrayType const*>(prefix);
solAssert(arrayPrefix, "");
prefix = arrayPrefix->baseType();
}
}
return false;
});
smt::Expression store = smt::Expression::store(
m_variables[varDecl]->currentValue(),
expr(*indexAccess.indexExpression()),
_rightHandSide
);
m_interface->addAssertion(newValue(*varDecl) == store);
// Update the SMT select value after the assignment,
// necessary for sound models.
defineExpr(indexAccess, smt::Expression::select(
m_variables[varDecl]->currentValue(),
expr(*indexAccess.indexExpression())
));
}
else if (dynamic_cast<IndexAccess const*>(&indexAccess.baseExpression()))
m_errorReporter.warning(
indexAccess.location(),
"Assertion checker does not yet implement assignments to multi-dimensional mappings or arrays."
);
else
m_errorReporter.warning(
_expr.location(),
"Assertion checker does not yet implement this expression."
);
}
void SMTChecker::defineGlobalVariable(string const& _name, Expression const& _expr, bool _increaseIndex)
{
if (!knownGlobalSymbol(_name))
{
auto result = newSymbolicVariable(*_expr.annotation().type, _name, *m_interface);
m_globalContext.emplace(_name, result.second);
setUnknownValue(*result.second);
if (result.first)
m_errorReporter.warning(
_expr.location(),
"Assertion checker does not yet support this global variable."
);
}
else if (_increaseIndex)
m_globalContext.at(_name)->increaseIndex();
// The default behavior is not to increase the index since
// most of the global values stay the same throughout a tx.
if (isSupportedType(_expr.annotation().type->category()))
defineExpr(_expr, m_globalContext.at(_name)->currentValue());
}
void SMTChecker::defineGlobalFunction(string const& _name, Expression const& _expr)
{
if (!knownGlobalSymbol(_name))
{
auto result = newSymbolicVariable(*_expr.annotation().type, _name, *m_interface);
m_globalContext.emplace(_name, result.second);
if (result.first)
m_errorReporter.warning(
_expr.location(),
"Assertion checker does not yet support the type of this function."
);
}
}
bool SMTChecker::shortcutRationalNumber(Expression const& _expr)
{
if (_expr.annotation().type->category() == Type::Category::RationalNumber)
{
auto rationalType = dynamic_cast<RationalNumberType const*>(_expr.annotation().type);
solAssert(rationalType, "");
if (rationalType->isNegative())
defineExpr(_expr, smt::Expression(u2s(rationalType->literalValue(nullptr))));
else
defineExpr(_expr, smt::Expression(rationalType->literalValue(nullptr)));
return true;
}
return false;
}
void SMTChecker::arithmeticOperation(BinaryOperation const& _op)
{
auto type = _op.annotation().commonType;
solAssert(type, "");
if (type->category() == Type::Category::Integer)
{
switch (_op.getOperator())
{
case Token::Add:
case Token::Sub:
case Token::Mul:
case Token::Div:
case Token::Mod:
{
defineExpr(_op, arithmeticOperation(
_op.getOperator(),
expr(_op.leftExpression()),
expr(_op.rightExpression()),
_op.annotation().commonType,
_op.location()
));
break;
}
default:
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement this operator."
);
}
}
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement this operator for type " + type->richIdentifier() + "."
);
}
smt::Expression SMTChecker::arithmeticOperation(
Token _op,
smt::Expression const& _left,
smt::Expression const& _right,
TypePointer const& _commonType,
langutil::SourceLocation const& _location
)
{
static set<Token> validOperators{
Token::Add,
Token::Sub,
Token::Mul,
Token::Div,
Token::Mod
};
solAssert(validOperators.count(_op), "");
solAssert(_commonType, "");
solAssert(_commonType->category() == Type::Category::Integer, "");
auto const& intType = dynamic_cast<IntegerType const&>(*_commonType);
smt::Expression value(
_op == Token::Add ? _left + _right :
_op == Token::Sub ? _left - _right :
_op == Token::Div ? division(_left, _right, intType) :
_op == Token::Mul ? _left * _right :
/*_op == Token::Mod*/ _left % _right
);
if (_op == Token::Div || _op == Token::Mod)
{
checkCondition(_right == 0, _location, "Division by zero", "<result>", &_right);
m_interface->addAssertion(_right != 0);
}
addOverflowTarget(
OverflowTarget::Type::All,
_commonType,
value,
_location
);
smt::Expression intValueRange = (0 - minValue(intType)) + maxValue(intType) + 1;
value = smt::Expression::ite(
value > maxValue(intType) || value < minValue(intType),
value % intValueRange,
value
);
if (intType.isSigned())
{
value = smt::Expression::ite(
value > maxValue(intType),
value - intValueRange,
value
);
}
return value;
}
void SMTChecker::compareOperation(BinaryOperation const& _op)
{
solAssert(_op.annotation().commonType, "");
if (isSupportedType(_op.annotation().commonType->category()))
{
smt::Expression left(expr(_op.leftExpression()));
smt::Expression right(expr(_op.rightExpression()));
Token op = _op.getOperator();
shared_ptr<smt::Expression> value;
if (isNumber(_op.annotation().commonType->category()))
{
value = make_shared<smt::Expression>(
op == Token::Equal ? (left == right) :
op == Token::NotEqual ? (left != right) :
op == Token::LessThan ? (left < right) :
op == Token::LessThanOrEqual ? (left <= right) :
op == Token::GreaterThan ? (left > right) :
/*op == Token::GreaterThanOrEqual*/ (left >= right)
);
}
else // Bool
{
solUnimplementedAssert(isBool(_op.annotation().commonType->category()), "Operation not yet supported");
value = make_shared<smt::Expression>(
op == Token::Equal ? (left == right) :
/*op == Token::NotEqual*/ (left != right)
);
}
// TODO: check that other values for op are not possible.
defineExpr(_op, *value);
}
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement the type " + _op.annotation().commonType->toString() + " for comparisons"
);
}
void SMTChecker::booleanOperation(BinaryOperation const& _op)
{
solAssert(_op.getOperator() == Token::And || _op.getOperator() == Token::Or, "");
solAssert(_op.annotation().commonType, "");
if (_op.annotation().commonType->category() == Type::Category::Bool)
{
// @TODO check that both of them are not constant
_op.leftExpression().accept(*this);
if (_op.getOperator() == Token::And)
{
auto indicesAfterSecond = visitBranch(&_op.rightExpression(), expr(_op.leftExpression()));
mergeVariables(touchedVariables(_op.rightExpression()), !expr(_op.leftExpression()), copyVariableIndices(), indicesAfterSecond);
defineExpr(_op, expr(_op.leftExpression()) && expr(_op.rightExpression()));
}
else
{
auto indicesAfterSecond = visitBranch(&_op.rightExpression(), !expr(_op.leftExpression()));
mergeVariables(touchedVariables(_op.rightExpression()), expr(_op.leftExpression()), copyVariableIndices(), indicesAfterSecond);
defineExpr(_op, expr(_op.leftExpression()) || expr(_op.rightExpression()));
}
}
else
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement the type " + _op.annotation().commonType->toString() + " for boolean operations"
);
}
smt::Expression SMTChecker::division(smt::Expression _left, smt::Expression _right, IntegerType const& _type)
{
// Signed division in SMTLIB2 rounds differently for negative division.
if (_type.isSigned())
return (smt::Expression::ite(
_left >= 0,
smt::Expression::ite(_right >= 0, _left / _right, 0 - (_left / (0 - _right))),
smt::Expression::ite(_right >= 0, 0 - ((0 - _left) / _right), (0 - _left) / (0 - _right))
));
else
return _left / _right;
}
void SMTChecker::assignment(
Expression const& _left,
vector<smt::Expression> const& _right,
TypePointer const& _type,
langutil::SourceLocation const& _location
)
{
if (!isSupportedType(_type->category()))
m_errorReporter.warning(
_location,
"Assertion checker does not yet implement type " + _type->toString()
);
else if (auto varDecl = identifierToVariable(_left))
{
solAssert(_right.size() == 1, "");
assignment(*varDecl, _right.front(), _location);
}
else if (dynamic_cast<IndexAccess const*>(&_left))
{
solAssert(_right.size() == 1, "");
arrayIndexAssignment(_left, _right.front());
}
else if (auto tuple = dynamic_cast<TupleExpression const*>(&_left))
{
auto const& components = tuple->components();
solAssert(_right.size() == components.size(), "");
for (unsigned i = 0; i < _right.size(); ++i)
if (auto component = components.at(i))
assignment(*component, {_right.at(i)}, component->annotation().type, component->location());
}
else
m_errorReporter.warning(
_location,
"Assertion checker does not yet implement such assignments."
);
}
smt::Expression SMTChecker::compoundAssignment(Assignment const& _assignment)
{
static map<Token, Token> const compoundToArithmetic{
{Token::AssignAdd, Token::Add},
{Token::AssignSub, Token::Sub},
{Token::AssignMul, Token::Mul},
{Token::AssignDiv, Token::Div},
{Token::AssignMod, Token::Mod}
};
Token op = _assignment.assignmentOperator();
solAssert(compoundToArithmetic.count(op), "");
auto decl = identifierToVariable(_assignment.leftHandSide());
return arithmeticOperation(
compoundToArithmetic.at(op),
decl ? currentValue(*decl) : expr(_assignment.leftHandSide()),
expr(_assignment.rightHandSide()),
_assignment.annotation().type,
_assignment.location()
);
}
void SMTChecker::assignment(VariableDeclaration const& _variable, Expression const& _value, SourceLocation const& _location)
{
assignment(_variable, expr(_value), _location);
}
void SMTChecker::assignment(VariableDeclaration const& _variable, smt::Expression const& _value, SourceLocation const& _location)
{
TypePointer type = _variable.type();
if (type->category() == Type::Category::Integer)
addOverflowTarget(OverflowTarget::Type::All, type, _value, _location);
else if (type->category() == Type::Category::Address)
addOverflowTarget(OverflowTarget::Type::All, TypeProvider::uint(160), _value, _location);
else if (type->category() == Type::Category::Mapping)
arrayAssignment();
m_interface->addAssertion(newValue(_variable) == _value);
}
SMTChecker::VariableIndices SMTChecker::visitBranch(ASTNode const* _statement, smt::Expression _condition)
{
return visitBranch(_statement, &_condition);
}
SMTChecker::VariableIndices SMTChecker::visitBranch(ASTNode const* _statement, smt::Expression const* _condition)
{
auto indicesBeforeBranch = copyVariableIndices();
if (_condition)
pushPathCondition(*_condition);
_statement->accept(*this);
if (_condition)
popPathCondition();
auto indicesAfterBranch = copyVariableIndices();
resetVariableIndices(indicesBeforeBranch);
return indicesAfterBranch;
}
void SMTChecker::checkCondition(
smt::Expression _condition,
SourceLocation const& _location,
string const& _description,
string const& _additionalValueName,
smt::Expression const* _additionalValue
)
{
m_interface->push();
addPathConjoinedExpression(_condition);
vector<smt::Expression> expressionsToEvaluate;
vector<string> expressionNames;
if (m_callStack.size())
{
solAssert(m_scanner, "");
if (_additionalValue)
{
expressionsToEvaluate.emplace_back(*_additionalValue);
expressionNames.push_back(_additionalValueName);
}
for (auto const& var: m_variables)
{
if (var.first->type()->isValueType())
{
expressionsToEvaluate.emplace_back(currentValue(*var.first));
expressionNames.push_back(var.first->name());
}
}
for (auto const& var: m_globalContext)
{
auto const& type = var.second->type();
if (
type->isValueType() &&
smtKind(type->category()) != smt::Kind::Function
)
{
expressionsToEvaluate.emplace_back(var.second->currentValue());
expressionNames.push_back(var.first);
}
}
for (auto const& uf: m_uninterpretedTerms)
{
if (uf->annotation().type->isValueType())
{
expressionsToEvaluate.emplace_back(expr(*uf));
expressionNames.push_back(m_scanner->sourceAt(uf->location()));
}
}
}
smt::CheckResult result;
vector<string> values;
tie(result, values) = checkSatisfiableAndGenerateModel(expressionsToEvaluate);
string extraComment;
if (m_loopExecutionHappened)
extraComment =
"\nNote that some information is erased after the execution of loops.\n"
"You can re-introduce information using require().";
if (m_arrayAssignmentHappened)
extraComment +=
"\nNote that array aliasing is not supported,"
" therefore all mapping information is erased after"
" a mapping local variable/parameter is assigned.\n"
"You can re-introduce information using require().";
if (m_externalFunctionCallHappened)
extraComment +=
"\nNote that external function calls are not inlined,"
" even if the source code of the function is available."
" This is due to the possibility that the actual called contract"
" has the same ABI but implements the function differently.";
SecondarySourceLocation secondaryLocation{};
secondaryLocation.append(extraComment, SourceLocation{});
switch (result)
{
case smt::CheckResult::SATISFIABLE:
{
std::ostringstream message;
message << _description << " happens here";
if (m_callStack.size())
{
std::ostringstream modelMessage;
modelMessage << " for:\n";
solAssert(values.size() == expressionNames.size(), "");
map<string, string> sortedModel;
for (size_t i = 0; i < values.size(); ++i)
if (expressionsToEvaluate.at(i).name != values.at(i))
sortedModel[expressionNames.at(i)] = values.at(i);
for (auto const& eval: sortedModel)
modelMessage << " " << eval.first << " = " << eval.second << "\n";
m_errorReporter.warning(
_location,
message.str(),
SecondarySourceLocation().append(modelMessage.str(), SourceLocation{})
.append(currentCallStack())
.append(move(secondaryLocation))
);
}
else
{
message << ".";
m_errorReporter.warning(_location, message.str(), secondaryLocation);
}
break;
}
case smt::CheckResult::UNSATISFIABLE:
break;
case smt::CheckResult::UNKNOWN:
m_errorReporter.warning(_location, _description + " might happen here.", secondaryLocation);
break;
case smt::CheckResult::CONFLICTING:
m_errorReporter.warning(_location, "At least two SMT solvers provided conflicting answers. Results might not be sound.");
break;
case smt::CheckResult::ERROR:
m_errorReporter.warning(_location, "Error trying to invoke SMT solver.");
break;
}
m_interface->pop();
}
void SMTChecker::checkBooleanNotConstant(Expression const& _condition, string const& _description)
{
// Do not check for const-ness if this is a constant.
if (dynamic_cast<Literal const*>(&_condition))
return;
m_interface->push();
addPathConjoinedExpression(expr(_condition));
auto positiveResult = checkSatisfiable();
m_interface->pop();
m_interface->push();
addPathConjoinedExpression(!expr(_condition));
auto negatedResult = checkSatisfiable();
m_interface->pop();
if (positiveResult == smt::CheckResult::ERROR || negatedResult == smt::CheckResult::ERROR)
m_errorReporter.warning(_condition.location(), "Error trying to invoke SMT solver.");
else if (positiveResult == smt::CheckResult::CONFLICTING || negatedResult == smt::CheckResult::CONFLICTING)
m_errorReporter.warning(_condition.location(), "At least two SMT solvers provided conflicting answers. Results might not be sound.");
else if (positiveResult == smt::CheckResult::SATISFIABLE && negatedResult == smt::CheckResult::SATISFIABLE)
{
// everything fine.
}
else if (positiveResult == smt::CheckResult::UNKNOWN || negatedResult == smt::CheckResult::UNKNOWN)
{
// can't do anything.
}
else if (positiveResult == smt::CheckResult::UNSATISFIABLE && negatedResult == smt::CheckResult::UNSATISFIABLE)
m_errorReporter.warning(_condition.location(), "Condition unreachable.", currentCallStack());
else
{
string value;
if (positiveResult == smt::CheckResult::SATISFIABLE)
{
solAssert(negatedResult == smt::CheckResult::UNSATISFIABLE, "");
value = "true";
}
else
{
solAssert(positiveResult == smt::CheckResult::UNSATISFIABLE, "");
solAssert(negatedResult == smt::CheckResult::SATISFIABLE, "");
value = "false";
}
m_errorReporter.warning(
_condition.location(),
boost::algorithm::replace_all_copy(_description, "$VALUE", value),
currentCallStack()
);
}
}
pair<smt::CheckResult, vector<string>>
SMTChecker::checkSatisfiableAndGenerateModel(vector<smt::Expression> const& _expressionsToEvaluate)
{
smt::CheckResult result;
vector<string> values;
try
{
tie(result, values) = m_interface->check(_expressionsToEvaluate);
}
catch (smt::SolverError const& _e)
{
string description("Error querying SMT solver");
if (_e.comment())
description += ": " + *_e.comment();
m_errorReporter.warning(description);
result = smt::CheckResult::ERROR;
}
for (string& value: values)
{
try
{
// Parse and re-format nicely
value = formatNumberReadable(bigint(value));
}
catch (...) { }
}
return make_pair(result, values);
}
smt::CheckResult SMTChecker::checkSatisfiable()
{
return checkSatisfiableAndGenerateModel({}).first;
}
void SMTChecker::initializeFunctionCallParameters(CallableDeclaration const& _function, vector<smt::Expression> const& _callArgs)
{
auto const& funParams = _function.parameters();
solAssert(funParams.size() == _callArgs.size(), "");
for (unsigned i = 0; i < funParams.size(); ++i)
if (createVariable(*funParams[i]))
{
m_interface->addAssertion(_callArgs[i] == newValue(*funParams[i]));
if (funParams[i]->annotation().type->category() == Type::Category::Mapping)
m_arrayAssignmentHappened = true;
}
for (auto const& variable: _function.localVariables())
if (createVariable(*variable))
{
newValue(*variable);
setZeroValue(*variable);
}
if (_function.returnParameterList())
for (auto const& retParam: _function.returnParameters())
if (createVariable(*retParam))
{
newValue(*retParam);
setZeroValue(*retParam);
}
}
void SMTChecker::initializeLocalVariables(FunctionDefinition const& _function)
{
for (auto const& variable: _function.localVariables())
if (createVariable(*variable))
setZeroValue(*variable);
for (auto const& param: _function.parameters())
if (createVariable(*param))
setUnknownValue(*param);
if (_function.returnParameterList())
for (auto const& retParam: _function.returnParameters())
if (createVariable(*retParam))
setZeroValue(*retParam);
}
void SMTChecker::removeLocalVariables()
{
for (auto it = m_variables.begin(); it != m_variables.end(); )
{
if (it->first->isLocalVariable())
it = m_variables.erase(it);
else
++it;
}
}
void SMTChecker::resetVariable(VariableDeclaration const& _variable)
{
newValue(_variable);
setUnknownValue(_variable);
}
void SMTChecker::resetStateVariables()
{
resetVariables([&](VariableDeclaration const& _variable) { return _variable.isStateVariable(); });
}
void SMTChecker::resetStorageReferences()
{
resetVariables([&](VariableDeclaration const& _variable) { return _variable.hasReferenceOrMappingType(); });
}
void SMTChecker::resetVariables(set<VariableDeclaration const*> const& _variables)
{
for (auto const* decl: _variables)
resetVariable(*decl);
}
void SMTChecker::resetVariables(function<bool(VariableDeclaration const&)> const& _filter)
{
for_each(begin(m_variables), end(m_variables), [&](auto _variable)
{
if (_filter(*_variable.first))
this->resetVariable(*_variable.first);
});
}
TypePointer SMTChecker::typeWithoutPointer(TypePointer const& _type)
{
if (auto refType = dynamic_cast<ReferenceType const*>(_type))
return TypeProvider::withLocationIfReference(refType->location(), _type);
return _type;
}
void SMTChecker::mergeVariables(set<VariableDeclaration const*> const& _variables, smt::Expression const& _condition, VariableIndices const& _indicesEndTrue, VariableIndices const& _indicesEndFalse)
{
auto cmp = [] (VariableDeclaration const* var1, VariableDeclaration const* var2) {
return var1->id() < var2->id();
};
set<VariableDeclaration const*, decltype(cmp)> sortedVars(begin(_variables), end(_variables), cmp);
for (auto const* decl: sortedVars)
{
solAssert(_indicesEndTrue.count(decl) && _indicesEndFalse.count(decl), "");
int trueIndex = _indicesEndTrue.at(decl);
int falseIndex = _indicesEndFalse.at(decl);
solAssert(trueIndex != falseIndex, "");
m_interface->addAssertion(newValue(*decl) == smt::Expression::ite(
_condition,
valueAtIndex(*decl, trueIndex),
valueAtIndex(*decl, falseIndex))
);
}
}
bool SMTChecker::createVariable(VariableDeclaration const& _varDecl)
{
// This might be the case for multiple calls to the same function.
if (knownVariable(_varDecl))
return true;
auto const& type = _varDecl.type();
solAssert(m_variables.count(&_varDecl) == 0, "");
auto result = newSymbolicVariable(*type, _varDecl.name() + "_" + to_string(_varDecl.id()), *m_interface);
m_variables.emplace(&_varDecl, result.second);
if (result.first)
{
m_errorReporter.warning(
_varDecl.location(),
"Assertion checker does not yet support the type of this variable."
);
return false;
}
return true;
}
bool SMTChecker::knownVariable(VariableDeclaration const& _decl)
{
return m_variables.count(&_decl);
}
smt::Expression SMTChecker::currentValue(VariableDeclaration const& _decl)
{
solAssert(knownVariable(_decl), "");
return m_variables.at(&_decl)->currentValue();
}
smt::Expression SMTChecker::valueAtIndex(VariableDeclaration const& _decl, int _index)
{
solAssert(knownVariable(_decl), "");
return m_variables.at(&_decl)->valueAtIndex(_index);
}
smt::Expression SMTChecker::newValue(VariableDeclaration const& _decl)
{
solAssert(knownVariable(_decl), "");
return m_variables.at(&_decl)->increaseIndex();
}
void SMTChecker::setZeroValue(VariableDeclaration const& _decl)
{
solAssert(knownVariable(_decl), "");
setZeroValue(*m_variables.at(&_decl));
}
void SMTChecker::setZeroValue(SymbolicVariable& _variable)
{
smt::setSymbolicZeroValue(_variable, *m_interface);
}
void SMTChecker::setUnknownValue(VariableDeclaration const& _decl)
{
solAssert(knownVariable(_decl), "");
setUnknownValue(*m_variables.at(&_decl));
}
void SMTChecker::setUnknownValue(SymbolicVariable& _variable)
{
smt::setSymbolicUnknownValue(_variable, *m_interface);
}
smt::Expression SMTChecker::expr(Expression const& _e)
{
if (!knownExpr(_e))
{
m_errorReporter.warning(_e.location(), "Internal error: Expression undefined for SMT solver." );
createExpr(_e);
}
return m_expressions.at(&_e)->currentValue();
}
bool SMTChecker::knownExpr(Expression const& _e) const
{
return m_expressions.count(&_e);
}
bool SMTChecker::knownGlobalSymbol(string const& _var) const
{
return m_globalContext.count(_var);
}
void SMTChecker::createExpr(Expression const& _e)
{
solAssert(_e.annotation().type, "");
if (knownExpr(_e))
m_expressions.at(&_e)->increaseIndex();
else
{
auto result = newSymbolicVariable(*_e.annotation().type, "expr_" + to_string(_e.id()), *m_interface);
m_expressions.emplace(&_e, result.second);
if (result.first)
m_errorReporter.warning(
_e.location(),
"Assertion checker does not yet implement this type."
);
}
}
void SMTChecker::defineExpr(Expression const& _e, smt::Expression _value)
{
createExpr(_e);
solAssert(smtKind(_e.annotation().type->category()) != smt::Kind::Function, "Equality operator applied to type that is not fully supported");
m_interface->addAssertion(expr(_e) == _value);
}
void SMTChecker::popPathCondition()
{
solAssert(m_pathConditions.size() > 0, "Cannot pop path condition, empty.");
m_pathConditions.pop_back();
}
void SMTChecker::pushPathCondition(smt::Expression const& _e)
{
m_pathConditions.push_back(currentPathConditions() && _e);
}
smt::Expression SMTChecker::currentPathConditions()
{
if (m_pathConditions.empty())
return smt::Expression(true);
return m_pathConditions.back();
}
SecondarySourceLocation SMTChecker::currentCallStack()
{
SecondarySourceLocation callStackLocation;
solAssert(!m_callStack.empty(), "");
callStackLocation.append("Callstack: ", SourceLocation());
for (auto const& call: m_callStack | boost::adaptors::reversed)
if (call.second)
callStackLocation.append("", call.second->location());
// The first function in the tx has no FunctionCall.
solAssert(m_callStack.front().second == nullptr, "");
return callStackLocation;
}
pair<CallableDeclaration const*, ASTNode const*> SMTChecker::popCallStack()
{
solAssert(!m_callStack.empty(), "");
auto lastCalled = m_callStack.back();
m_callStack.pop_back();
return lastCalled;
}
void SMTChecker::pushCallStack(CallStackEntry _entry)
{
m_callStack.push_back(_entry);
}
void SMTChecker::addPathConjoinedExpression(smt::Expression const& _e)
{
m_interface->addAssertion(currentPathConditions() && _e);
}
void SMTChecker::addPathImpliedExpression(smt::Expression const& _e)
{
m_interface->addAssertion(smt::Expression::implies(currentPathConditions(), _e));
}
bool SMTChecker::isRootFunction()
{
return m_callStack.size() == 1;
}
bool SMTChecker::visitedFunction(FunctionDefinition const* _funDef)
{
for (auto const& call: m_callStack)
if (call.first == _funDef)
return true;
return false;
}
SMTChecker::VariableIndices SMTChecker::copyVariableIndices()
{
VariableIndices indices;
for (auto const& var: m_variables)
indices.emplace(var.first, var.second->index());
return indices;
}
void SMTChecker::resetVariableIndices(VariableIndices const& _indices)
{
for (auto const& var: _indices)
m_variables.at(var.first)->index() = var.second;
}
FunctionDefinition const* SMTChecker::inlinedFunctionCallToDefinition(FunctionCall const& _funCall)
{
if (_funCall.annotation().kind != FunctionCallKind::FunctionCall)
return nullptr;
FunctionType const& funType = dynamic_cast<FunctionType const&>(*_funCall.expression().annotation().type);
if (funType.kind() == FunctionType::Kind::External)
{
auto memberAccess = dynamic_cast<MemberAccess const*>(&_funCall.expression());
auto identifier = memberAccess ?
dynamic_cast<Identifier const*>(&memberAccess->expression()) :
nullptr;
if (!(
identifier &&
identifier->name() == "this" &&
identifier->annotation().referencedDeclaration &&
dynamic_cast<MagicVariableDeclaration const*>(identifier->annotation().referencedDeclaration)
))
return nullptr;
}
else if (funType.kind() != FunctionType::Kind::Internal)
return nullptr;
FunctionDefinition const* funDef = nullptr;
Expression const* calledExpr = &_funCall.expression();
if (TupleExpression const* fun = dynamic_cast<TupleExpression const*>(&_funCall.expression()))
{
solAssert(fun->components().size() == 1, "");
calledExpr = fun->components().front().get();
}
if (Identifier const* fun = dynamic_cast<Identifier const*>(calledExpr))
funDef = dynamic_cast<FunctionDefinition const*>(fun->annotation().referencedDeclaration);
else if (MemberAccess const* fun = dynamic_cast<MemberAccess const*>(calledExpr))
funDef = dynamic_cast<FunctionDefinition const*>(fun->annotation().referencedDeclaration);
if (funDef && funDef->isImplemented())
return funDef;
return nullptr;
}
set<VariableDeclaration const*> SMTChecker::touchedVariables(ASTNode const& _node)
{
solAssert(!m_callStack.empty(), "");
vector<CallableDeclaration const*> callStack;
for (auto const& call: m_callStack)
callStack.push_back(call.first);
return m_variableUsage.touchedVariables(_node, callStack);
}
VariableDeclaration const* SMTChecker::identifierToVariable(Expression const& _expr)
{
if (auto identifier = dynamic_cast<Identifier const*>(&_expr))
{
if (auto decl = dynamic_cast<VariableDeclaration const*>(identifier->annotation().referencedDeclaration))
{
solAssert(knownVariable(*decl), "");
return decl;
}
}
return nullptr;
}