diff --git a/libsolidity/formal/SMTChecker.cpp b/libsolidity/formal/SMTChecker.cpp index a22e35d64..61cb110ec 100644 --- a/libsolidity/formal/SMTChecker.cpp +++ b/libsolidity/formal/SMTChecker.cpp @@ -71,6 +71,7 @@ bool SMTChecker::visit(FunctionDefinition const& _function) m_interface->reset(); m_currentSequenceCounter.clear(); m_nextFreeSequenceCounter.clear(); + m_pathConditions.clear(); m_conditionalExecutionHappened = false; initializeLocalVariables(_function); return true; @@ -344,14 +345,14 @@ void SMTChecker::endVisit(FunctionCall const& _funCall) solAssert(args.size() == 1, ""); solAssert(args[0]->annotation().type->category() == Type::Category::Bool, ""); checkCondition(!(expr(*args[0])), _funCall.location(), "Assertion violation"); - m_interface->addAssertion(expr(*args[0])); + m_interface->addAssertion(smt::Expression::implies(currentPathConditions(), expr(*args[0]))); } else if (funType.kind() == FunctionType::Kind::Require) { solAssert(args.size() == 1, ""); solAssert(args[0]->annotation().type->category() == Type::Category::Bool, ""); checkBooleanNotConstant(*args[0], "Condition is always $VALUE."); - m_interface->addAssertion(expr(*args[0])); + m_interface->addAssertion(smt::Expression::implies(currentPathConditions(), expr(*args[0]))); } } @@ -514,11 +515,11 @@ void SMTChecker::visitBranch(Statement const& _statement, smt::Expression const* { VariableSequenceCounters sequenceCountersStart = m_currentSequenceCounter; - m_interface->push(); if (_condition) - m_interface->addAssertion(*_condition); + pushPathCondition(*_condition); _statement.accept(*this); - m_interface->pop(); + if (_condition) + popPathCondition(); m_conditionalExecutionHappened = true; m_currentSequenceCounter = sequenceCountersStart; @@ -533,7 +534,7 @@ void SMTChecker::checkCondition( ) { m_interface->push(); - m_interface->addAssertion(_condition); + m_interface->addAssertion(currentPathConditions() && _condition); vector expressionsToEvaluate; vector expressionNames; @@ -605,12 +606,12 @@ void SMTChecker::checkBooleanNotConstant(Expression const& _condition, string co return; m_interface->push(); - m_interface->addAssertion(expr(_condition)); + m_interface->addAssertion(currentPathConditions() && expr(_condition)); auto positiveResult = checkSatisifable(); m_interface->pop(); m_interface->push(); - m_interface->addAssertion(!expr(_condition)); + m_interface->addAssertion(currentPathConditions() && !expr(_condition)); auto negatedResult = checkSatisifable(); m_interface->pop(); @@ -828,3 +829,21 @@ smt::Expression SMTChecker::var(Declaration const& _decl) solAssert(m_variables.count(&_decl), ""); return m_variables.at(&_decl); } + +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.size() == 0) + return smt::Expression(true); + return m_pathConditions.back(); +} diff --git a/libsolidity/formal/SMTChecker.h b/libsolidity/formal/SMTChecker.h index e7481ccaf..7f990b979 100644 --- a/libsolidity/formal/SMTChecker.h +++ b/libsolidity/formal/SMTChecker.h @@ -26,6 +26,7 @@ #include #include +#include namespace dev { @@ -145,6 +146,13 @@ private: /// The function takes one argument which is the "sequence number". smt::Expression var(Declaration const& _decl); + /// Adds a new path condition + void pushPathCondition(smt::Expression const& _e); + /// Remove the last path condition + void popPathCondition(); + /// Returns the conjunction of all path conditions or True if empty + smt::Expression currentPathConditions(); + std::shared_ptr m_interface; std::shared_ptr m_variableUsage; bool m_conditionalExecutionHappened = false; @@ -152,6 +160,7 @@ private: std::map m_nextFreeSequenceCounter; std::map m_expressions; std::map m_variables; + std::vector m_pathConditions; ErrorReporter& m_errorReporter; FunctionDefinition const* m_currentFunction = nullptr; diff --git a/libsolidity/formal/SolverInterface.h b/libsolidity/formal/SolverInterface.h index 74c993e85..884873100 100644 --- a/libsolidity/formal/SolverInterface.h +++ b/libsolidity/formal/SolverInterface.h @@ -72,6 +72,11 @@ public: }, _trueValue.sort); } + static Expression implies(Expression _a, Expression _b) + { + return !std::move(_a) || std::move(_b); + } + friend Expression operator!(Expression _a) { return Expression("not", std::move(_a), Sort::Bool);