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[SMTChecker] Keep track of current path conditions

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This commit is contained in:
Leonardo Alt 2017-12-11 20:09:17 +01:00
parent bfc5446318
commit 2af4d7c7dd
3 changed files with 41 additions and 8 deletions
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35
libsolidity/formal/SMTChecker.cpp
View File

@ -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<smt::Expression> expressionsToEvaluate;
vector<string> 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();
}

9
libsolidity/formal/SMTChecker.h
View File

@ -26,6 +26,7 @@
#include <map>
#include <string>
#include <vector>
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<smt::SolverInterface> m_interface;
std::shared_ptr<VariableUsage> m_variableUsage;
bool m_conditionalExecutionHappened = false;
@ -152,6 +160,7 @@ private:
std::map<Declaration const*, int> m_nextFreeSequenceCounter;
std::map<Expression const*, smt::Expression> m_expressions;
std::map<Declaration const*, smt::Expression> m_variables;
std::vector<smt::Expression> m_pathConditions;
ErrorReporter& m_errorReporter;
FunctionDefinition const* m_currentFunction = nullptr;

5
libsolidity/formal/SolverInterface.h
View File

@ -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);