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CHC.cpp
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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/>.
*/
// SPDX-License-Identifier: GPL-3.0
#include <libsolidity/formal/CHC.h>
#include <libsolidity/formal/ArraySlicePredicate.h>
#include <libsolidity/formal/ExpressionFormatter.h>
#include <libsolidity/formal/EldaricaCHCSmtLib2Interface.h>
#include <libsolidity/formal/ModelChecker.h>
#include <libsolidity/formal/PredicateInstance.h>
#include <libsolidity/formal/PredicateSort.h>
#include <libsolidity/formal/SymbolicTypes.h>
#include <libsolidity/formal/Z3CHCSmtLib2Interface.h>
#include <libsolidity/ast/TypeProvider.h>
#include <libsmtutil/CHCSmtLib2Interface.h>
#include <liblangutil/CharStreamProvider.h>
#include <libsolutil/Algorithms.h>
#include <libsolutil/StringUtils.h>
#include <range/v3/algorithm/for_each.hpp>
#include <range/v3/algorithm/none_of.hpp>
#include <range/v3/view.hpp>
#include <range/v3/view/enumerate.hpp>
#include <range/v3/view/reverse.hpp>
#include <charconv>
#include <queue>
using namespace solidity;
using namespace solidity::util;
using namespace solidity::langutil;
using namespace solidity::smtutil;
using namespace solidity::frontend;
using namespace solidity::frontend::smt;
CHC::CHC(
EncodingContext& _context,
UniqueErrorReporter& _errorReporter,
UniqueErrorReporter& _unsupportedErrorReporter,
ErrorReporter& _provedSafeReporter,
std::map<util::h256, std::string> const& _smtlib2Responses,
ReadCallback::Callback const& _smtCallback,
ModelCheckerSettings _settings,
CharStreamProvider const& _charStreamProvider
):
SMTEncoder(_context, _settings, _errorReporter, _unsupportedErrorReporter, _provedSafeReporter, _charStreamProvider),
m_smtlib2Responses(_smtlib2Responses),
m_smtCallback(_smtCallback)
{}
void CHC::analyze(SourceUnit const& _source)
{
// At this point every enabled solver is available.
if (!m_settings.solvers.eld && !m_settings.solvers.smtlib2 && !m_settings.solvers.z3)
{
m_errorReporter.warning(
7649_error,
SourceLocation(),
"CHC analysis was not possible since no Horn solver was found and enabled."
" The accepted solvers for CHC are Eldarica and z3."
);
return;
}
if (m_settings.solvers.eld && m_settings.solvers.z3)
m_errorReporter.warning(
5798_error,
SourceLocation(),
"Multiple Horn solvers were selected for CHC."
" CHC only supports one solver at a time, therefore only z3 will be used."
" If you wish to use Eldarica, please enable Eldarica only."
);
if (!shouldAnalyzeVerificationTargetsFor(_source))
return;
resetSourceAnalysis();
auto sources = sourceDependencies(_source);
collectFreeFunctions(sources);
createFreeConstants(sources);
state().prepareForSourceUnit(_source, encodeExternalCallsAsTrusted());
for (auto const* source: sources)
defineInterfacesAndSummaries(*source);
for (auto const* source: sources)
source->accept(*this);
checkVerificationTargets();
bool ranSolver = true;
// If ranSolver is true here it's because an SMT solver callback was
// actually given and the queries were solved,
// or Eldarica was chosen and was present in the system.
if (auto const* smtLibInterface = dynamic_cast<CHCSmtLib2Interface const*>(m_interface.get()))
ranSolver = smtLibInterface->unhandledQueries().empty();
if (!ranSolver)
m_errorReporter.warning(
3996_error,
SourceLocation(),
"CHC analysis was not possible. No Horn solver was available."
" None of the installed solvers was enabled."
);
}
std::vector<std::string> CHC::unhandledQueries() const
{
if (auto smtlib2 = dynamic_cast<CHCSmtLib2Interface const*>(m_interface.get()))
return smtlib2->unhandledQueries();
return {};
}
bool CHC::visit(ContractDefinition const& _contract)
{
if (!shouldEncode(_contract))
return false;
// Raises UnimplementedFeatureError in the presence of transient storage variables
TransientDataLocationChecker checker(_contract);
resetContractAnalysis();
initContract(_contract);
clearIndices(&_contract);
m_scopes.push_back(&_contract);
m_stateVariables = SMTEncoder::stateVariablesIncludingInheritedAndPrivate(_contract);
solAssert(m_currentContract, "");
SMTEncoder::visit(_contract);
return false;
}
void CHC::endVisit(ContractDefinition const& _contract)
{
if (!shouldEncode(_contract))
return;
for (auto base: _contract.annotation().linearizedBaseContracts)
{
if (auto constructor = base->constructor())
constructor->accept(*this);
defineContractInitializer(*base, _contract);
}
auto const& entry = *createConstructorBlock(_contract, "implicit_constructor_entry");
// In case constructors use uninitialized state variables,
// they need to be zeroed.
// This is not part of `initialConstraints` because it's only true here,
// at the beginning of the deployment routine.
smtutil::Expression zeroes(true);
for (auto var: stateVariablesIncludingInheritedAndPrivate(_contract))
zeroes = zeroes && currentValue(*var) == smt::zeroValue(var->type());
smtutil::Expression newAddress = encodeExternalCallsAsTrusted() ?
!state().addressActive(state().thisAddress()) :
smtutil::Expression(true);
// The contract's address might already have funds before deployment,
// so the balance must be at least `msg.value`, but not equals.
auto initialBalanceConstraint = state().balance(state().thisAddress()) >= state().txMember("msg.value");
addRule(smtutil::Expression::implies(
initialConstraints(_contract) && zeroes && newAddress && initialBalanceConstraint,
predicate(entry)
), entry.functor().name);
setCurrentBlock(entry);
if (encodeExternalCallsAsTrusted())
{
auto const& entryAfterAddress = *createConstructorBlock(_contract, "implicit_constructor_entry_after_address");
state().setAddressActive(state().thisAddress(), true);
connectBlocks(m_currentBlock, predicate(entryAfterAddress));
setCurrentBlock(entryAfterAddress);
}
solAssert(!m_errorDest, "");
m_errorDest = m_constructorSummaries.at(&_contract);
// We need to evaluate the base constructor calls (arguments) from derived -> base
auto baseArgs = baseArguments(_contract);
for (auto base: _contract.annotation().linearizedBaseContracts)
if (base != &_contract)
{
m_callGraph[&_contract].insert(base);
auto baseConstructor = base->constructor();
if (baseConstructor && baseArgs.count(base))
{
std::vector<ASTPointer<Expression>> const& args = baseArgs.at(base);
auto const& params = baseConstructor->parameters();
solAssert(params.size() == args.size(), "");
for (unsigned i = 0; i < params.size(); ++i)
{
args.at(i)->accept(*this);
if (params.at(i))
{
solAssert(m_context.knownVariable(*params.at(i)), "");
m_context.addAssertion(currentValue(*params.at(i)) == expr(*args.at(i), params.at(i)->type()));
}
}
}
}
m_errorDest = nullptr;
// Then call initializer_Base from base -> derived
for (auto base: _contract.annotation().linearizedBaseContracts | ranges::views::reverse)
{
errorFlag().increaseIndex();
m_context.addAssertion(smt::constructorCall(*m_contractInitializers.at(&_contract).at(base), m_context));
connectBlocks(m_currentBlock, summary(_contract), errorFlag().currentValue() > 0);
m_context.addAssertion(errorFlag().currentValue() == 0);
}
if (encodeExternalCallsAsTrusted())
state().writeStateVars(_contract, state().thisAddress());
connectBlocks(m_currentBlock, summary(_contract));
setCurrentBlock(*m_constructorSummaries.at(&_contract));
solAssert(&_contract == m_currentContract, "");
smtAssert(shouldEncode(_contract));
auto constructor = _contract.constructor();
auto txConstraints = state().txTypeConstraints();
if (!constructor || !constructor->isPayable())
txConstraints = txConstraints && state().txNonPayableConstraint();
connectBlocks(m_currentBlock, interface(), txConstraints && errorFlag().currentValue() == 0);
if (shouldAnalyzeVerificationTargetsFor(_contract))
m_queryPlaceholders[&_contract].push_back({txConstraints, errorFlag().currentValue(), m_currentBlock});
solAssert(m_scopes.back() == &_contract, "");
m_scopes.pop_back();
SMTEncoder::endVisit(_contract);
}
bool CHC::visit(FunctionDefinition const& _function)
{
// Free functions need to be visited in the context of a contract.
if (!m_currentContract)
return false;
if (
!_function.isImplemented() ||
abstractAsNondet(_function)
)
{
smtutil::Expression conj(true);
if (
_function.stateMutability() == StateMutability::Pure ||
_function.stateMutability() == StateMutability::View
)
conj = conj && currentEqualInitialVarsConstraints(stateVariablesIncludingInheritedAndPrivate(_function));
conj = conj && errorFlag().currentValue() == 0;
addRule(smtutil::Expression::implies(conj, summary(_function)), "summary_function_" + std::to_string(_function.id()));
return false;
}
// No inlining.
solAssert(!m_currentFunction, "Function inlining should not happen in CHC.");
m_currentFunction = &_function;
m_scopes.push_back(&_function);
initFunction(_function);
auto functionEntryBlock = createBlock(m_currentFunction, PredicateType::FunctionBlock);
auto bodyBlock = createBlock(&m_currentFunction->body(), PredicateType::FunctionBlock);
auto functionPred = predicate(*functionEntryBlock);
auto bodyPred = predicate(*bodyBlock);
addRule(functionPred, functionPred.name);
solAssert(m_currentContract, "");
m_context.addAssertion(initialConstraints(*m_currentContract, &_function));
connectBlocks(functionPred, bodyPred);
setCurrentBlock(*bodyBlock);
solAssert(!m_errorDest, "");
m_errorDest = m_summaries.at(m_currentContract).at(&_function);
SMTEncoder::visit(*m_currentFunction);
m_errorDest = nullptr;
return false;
}
void CHC::endVisit(FunctionDefinition const& _function)
{
// Free functions need to be visited in the context of a contract.
if (!m_currentContract)
return;
if (
!_function.isImplemented() ||
abstractAsNondet(_function)
)
return;
solAssert(m_currentFunction && m_currentContract, "");
// No inlining.
solAssert(m_currentFunction == &_function, "");
solAssert(m_scopes.back() == &_function, "");
m_scopes.pop_back();
connectBlocks(m_currentBlock, summary(_function));
setCurrentBlock(*m_summaries.at(m_currentContract).at(&_function));
// Query placeholders for constructors are not created here because
// of contracts without constructors.
// Instead, those are created in endVisit(ContractDefinition).
if (
!_function.isConstructor() &&
_function.isPublic() &&
contractFunctions(*m_currentContract).count(&_function) &&
shouldEncode(*m_currentContract)
)
{
defineExternalFunctionInterface(_function, *m_currentContract);
setCurrentBlock(*m_interfaces.at(m_currentContract));
// Create the rule
// interface \land externalFunctionEntry => interface'
auto ifacePre = smt::interfacePre(*m_interfaces.at(m_currentContract), *m_currentContract, m_context);
auto sum = externalSummary(_function);
connectBlocks(ifacePre, interface(), sum && errorFlag().currentValue() == 0);
if (shouldAnalyzeVerificationTargetsFor(*m_currentContract))
m_queryPlaceholders[&_function].push_back({sum, errorFlag().currentValue(), ifacePre});
}
m_currentFunction = nullptr;
SMTEncoder::endVisit(_function);
}
bool CHC::visit(Block const& _block)
{
m_scopes.push_back(&_block);
return SMTEncoder::visit(_block);
}
void CHC::endVisit(Block const& _block)
{
solAssert(m_scopes.back() == &_block, "");
m_scopes.pop_back();
SMTEncoder::endVisit(_block);
}
bool CHC::visit(IfStatement const& _if)
{
solAssert(m_currentFunction, "");
bool unknownFunctionCallWasSeen = m_unknownFunctionCallSeen;
m_unknownFunctionCallSeen = false;
solAssert(m_currentFunction, "");
auto const& functionBody = m_currentFunction->body();
auto ifHeaderBlock = createBlock(&_if, PredicateType::FunctionBlock, "if_header_");
auto trueBlock = createBlock(&_if.trueStatement(), PredicateType::FunctionBlock, "if_true_");
auto falseBlock = _if.falseStatement() ? createBlock(_if.falseStatement(), PredicateType::FunctionBlock, "if_false_") : nullptr;
auto afterIfBlock = createBlock(&functionBody, PredicateType::FunctionBlock);
connectBlocks(m_currentBlock, predicate(*ifHeaderBlock));
setCurrentBlock(*ifHeaderBlock);
_if.condition().accept(*this);
auto condition = expr(_if.condition());
connectBlocks(m_currentBlock, predicate(*trueBlock), condition);
if (_if.falseStatement())
connectBlocks(m_currentBlock, predicate(*falseBlock), !condition);
else
connectBlocks(m_currentBlock, predicate(*afterIfBlock), !condition);
setCurrentBlock(*trueBlock);
_if.trueStatement().accept(*this);
connectBlocks(m_currentBlock, predicate(*afterIfBlock));
if (_if.falseStatement())
{
setCurrentBlock(*falseBlock);
_if.falseStatement()->accept(*this);
connectBlocks(m_currentBlock, predicate(*afterIfBlock));
}
setCurrentBlock(*afterIfBlock);
if (m_unknownFunctionCallSeen)
eraseKnowledge();
m_unknownFunctionCallSeen = unknownFunctionCallWasSeen;
return false;
}
bool CHC::visit(WhileStatement const& _while)
{
bool unknownFunctionCallWasSeen = m_unknownFunctionCallSeen;
m_unknownFunctionCallSeen = false;
solAssert(m_currentFunction, "");
auto const& functionBody = m_currentFunction->body();
auto namePrefix = std::string(_while.isDoWhile() ? "do_" : "") + "while";
auto loopHeaderBlock = createBlock(&_while, PredicateType::FunctionBlock, namePrefix + "_header_");
auto loopBodyBlock = createBlock(&_while.body(), PredicateType::FunctionBlock, namePrefix + "_body_");
auto afterLoopBlock = createBlock(&functionBody, PredicateType::FunctionBlock);
auto outerBreakDest = m_breakDest;
auto outerContinueDest = m_continueDest;
m_breakDest = afterLoopBlock;
m_continueDest = loopHeaderBlock;
if (_while.isDoWhile())
_while.body().accept(*this);
connectBlocks(m_currentBlock, predicate(*loopHeaderBlock));
setCurrentBlock(*loopHeaderBlock);
_while.condition().accept(*this);
auto condition = expr(_while.condition());
connectBlocks(m_currentBlock, predicate(*loopBodyBlock), condition);
connectBlocks(m_currentBlock, predicate(*afterLoopBlock), !condition);
// Loop body visit.
setCurrentBlock(*loopBodyBlock);
_while.body().accept(*this);
m_breakDest = outerBreakDest;
m_continueDest = outerContinueDest;
// Back edge.
connectBlocks(m_currentBlock, predicate(*loopHeaderBlock));
setCurrentBlock(*afterLoopBlock);
if (m_unknownFunctionCallSeen)
eraseKnowledge();
m_unknownFunctionCallSeen = unknownFunctionCallWasSeen;
return false;
}
bool CHC::visit(ForStatement const& _for)
{
m_scopes.push_back(&_for);
bool unknownFunctionCallWasSeen = m_unknownFunctionCallSeen;
m_unknownFunctionCallSeen = false;
solAssert(m_currentFunction, "");
auto const& functionBody = m_currentFunction->body();
auto loopHeaderBlock = createBlock(&_for, PredicateType::FunctionBlock, "for_header_");
auto loopBodyBlock = createBlock(&_for.body(), PredicateType::FunctionBlock, "for_body_");
auto afterLoopBlock = createBlock(&functionBody, PredicateType::FunctionBlock);
auto postLoop = _for.loopExpression();
auto postLoopBlock = postLoop ? createBlock(postLoop, PredicateType::FunctionBlock, "for_post_") : nullptr;
auto outerBreakDest = m_breakDest;
auto outerContinueDest = m_continueDest;
m_breakDest = afterLoopBlock;
m_continueDest = postLoop ? postLoopBlock : loopHeaderBlock;
if (auto init = _for.initializationExpression())
init->accept(*this);
connectBlocks(m_currentBlock, predicate(*loopHeaderBlock));
setCurrentBlock(*loopHeaderBlock);
auto condition = smtutil::Expression(true);
if (auto forCondition = _for.condition())
{
forCondition->accept(*this);
condition = expr(*forCondition);
}
connectBlocks(m_currentBlock, predicate(*loopBodyBlock), condition);
connectBlocks(m_currentBlock, predicate(*afterLoopBlock), !condition);
// Loop body visit.
setCurrentBlock(*loopBodyBlock);
_for.body().accept(*this);
if (postLoop)
{
connectBlocks(m_currentBlock, predicate(*postLoopBlock));
setCurrentBlock(*postLoopBlock);
postLoop->accept(*this);
}
m_breakDest = outerBreakDest;
m_continueDest = outerContinueDest;
// Back edge.
connectBlocks(m_currentBlock, predicate(*loopHeaderBlock));
setCurrentBlock(*afterLoopBlock);
if (m_unknownFunctionCallSeen)
eraseKnowledge();
m_unknownFunctionCallSeen = unknownFunctionCallWasSeen;
return false;
}
void CHC::endVisit(ForStatement const& _for)
{
solAssert(m_scopes.back() == &_for, "");
m_scopes.pop_back();
}
void CHC::endVisit(UnaryOperation const& _op)
{
SMTEncoder::endVisit(_op);
if (auto funDef = *_op.annotation().userDefinedFunction)
{
std::vector<Expression const*> arguments;
arguments.push_back(&_op.subExpression());
internalFunctionCall(funDef, std::nullopt, _op.userDefinedFunctionType(), arguments, state().thisAddress());
createReturnedExpressions(funDef, _op);
return;
}
if (
_op.annotation().type->category() == Type::Category::RationalNumber ||
_op.annotation().type->category() == Type::Category::FixedPoint
)
return;
if (_op.getOperator() == Token::Sub && smt::isInteger(*_op.annotation().type))
{
auto const* intType = dynamic_cast<IntegerType const*>(_op.annotation().type);
if (!intType)
intType = TypeProvider::uint256();
verificationTargetEncountered(&_op, VerificationTargetType::Underflow, expr(_op) < intType->minValue());
verificationTargetEncountered(&_op, VerificationTargetType::Overflow, expr(_op) > intType->maxValue());
}
}
void CHC::endVisit(BinaryOperation const& _op)
{
SMTEncoder::endVisit(_op);
if (auto funDef = *_op.annotation().userDefinedFunction)
{
std::vector<Expression const*> arguments;
arguments.push_back(&_op.leftExpression());
arguments.push_back(&_op.rightExpression());
internalFunctionCall(funDef, std::nullopt, _op.userDefinedFunctionType(), arguments, state().thisAddress());
createReturnedExpressions(funDef, _op);
}
}
void CHC::endVisit(FunctionCall const& _funCall)
{
auto functionCallKind = *_funCall.annotation().kind;
if (functionCallKind != FunctionCallKind::FunctionCall)
{
SMTEncoder::endVisit(_funCall);
return;
}
FunctionType const& funType = dynamic_cast<FunctionType const&>(*_funCall.expression().annotation().type);
switch (funType.kind())
{
case FunctionType::Kind::Assert:
visitAssert(_funCall);
SMTEncoder::endVisit(_funCall);
break;
case FunctionType::Kind::Internal:
internalFunctionCall(_funCall);
break;
case FunctionType::Kind::External:
case FunctionType::Kind::BareStaticCall:
case FunctionType::Kind::BareCall:
externalFunctionCall(_funCall);
SMTEncoder::endVisit(_funCall);
break;
case FunctionType::Kind::Creation:
visitDeployment(_funCall);
break;
case FunctionType::Kind::DelegateCall:
case FunctionType::Kind::BareCallCode:
case FunctionType::Kind::BareDelegateCall:
SMTEncoder::endVisit(_funCall);
unknownFunctionCall(_funCall);
break;
case FunctionType::Kind::Send:
case FunctionType::Kind::Transfer:
{
auto value = _funCall.arguments().front();
solAssert(value, "");
smtutil::Expression thisBalance = state().balance();
verificationTargetEncountered(
&_funCall,
VerificationTargetType::Balance,
thisBalance < expr(*value)
);
SMTEncoder::endVisit(_funCall);
break;
}
case FunctionType::Kind::KECCAK256:
case FunctionType::Kind::ECRecover:
case FunctionType::Kind::SHA256:
case FunctionType::Kind::RIPEMD160:
case FunctionType::Kind::BlobHash:
case FunctionType::Kind::BlockHash:
case FunctionType::Kind::AddMod:
case FunctionType::Kind::MulMod:
case FunctionType::Kind::Unwrap:
case FunctionType::Kind::Wrap:
[[fallthrough]];
default:
SMTEncoder::endVisit(_funCall);
break;
}
auto funDef = functionCallToDefinition(_funCall, currentScopeContract(), m_currentContract);
createReturnedExpressions(funDef, _funCall);
}
void CHC::endVisit(Break const& _break)
{
solAssert(m_breakDest, "");
connectBlocks(m_currentBlock, predicate(*m_breakDest));
// Add an unreachable ghost node to collect unreachable statements after a break.
auto breakGhost = createBlock(&_break, PredicateType::FunctionBlock, "break_ghost_");
m_currentBlock = predicate(*breakGhost);
}
void CHC::endVisit(Continue const& _continue)
{
solAssert(m_continueDest, "");
connectBlocks(m_currentBlock, predicate(*m_continueDest));
// Add an unreachable ghost node to collect unreachable statements after a continue.
auto continueGhost = createBlock(&_continue, PredicateType::FunctionBlock, "continue_ghost_");
m_currentBlock = predicate(*continueGhost);
}
void CHC::endVisit(IndexRangeAccess const& _range)
{
createExpr(_range);
auto baseArray = std::dynamic_pointer_cast<SymbolicArrayVariable>(m_context.expression(_range.baseExpression()));
auto sliceArray = std::dynamic_pointer_cast<SymbolicArrayVariable>(m_context.expression(_range));
solAssert(baseArray && sliceArray, "");
auto const& sliceData = ArraySlicePredicate::create(sliceArray->sort(), m_context);
if (!sliceData.first)
{
for (auto pred: sliceData.second.predicates)
m_interface->registerRelation(pred->functor());
for (auto const& rule: sliceData.second.rules)
addRule(rule, "");
}
auto start = _range.startExpression() ? expr(*_range.startExpression()) : 0;
auto end = _range.endExpression() ? expr(*_range.endExpression()) : baseArray->length();
auto slicePred = (*sliceData.second.predicates.at(0))({
baseArray->elements(),
sliceArray->elements(),
start,
end
});
m_context.addAssertion(slicePred);
m_context.addAssertion(sliceArray->length() == end - start);
}
void CHC::endVisit(Return const& _return)
{
SMTEncoder::endVisit(_return);
connectBlocks(m_currentBlock, predicate(*m_returnDests.back()));
// Add an unreachable ghost node to collect unreachable statements after a return.
auto returnGhost = createBlock(&_return, PredicateType::FunctionBlock, "return_ghost_");
m_currentBlock = predicate(*returnGhost);
}
bool CHC::visit(TryCatchClause const& _tryStatement)
{
m_scopes.push_back(&_tryStatement);
return SMTEncoder::visit(_tryStatement);
}
void CHC::endVisit(TryCatchClause const& _tryStatement)
{
solAssert(m_scopes.back() == &_tryStatement, "");
m_scopes.pop_back();
}
bool CHC::visit(TryStatement const& _tryStatement)
{
FunctionCall const* externalCall = dynamic_cast<FunctionCall const*>(&_tryStatement.externalCall());
solAssert(externalCall && externalCall->annotation().tryCall, "");
solAssert(m_currentFunction, "");
auto tryHeaderBlock = createBlock(&_tryStatement, PredicateType::FunctionBlock, "try_header_");
auto afterTryBlock = createBlock(&m_currentFunction->body(), PredicateType::FunctionBlock);
auto const& clauses = _tryStatement.clauses();
solAssert(clauses[0].get() == _tryStatement.successClause(), "First clause of TryStatement should be the success clause");
auto clauseBlocks = applyMap(clauses, [this](ASTPointer<TryCatchClause> clause) {
return createBlock(clause.get(), PredicateType::FunctionBlock, "try_clause_" + std::to_string(clause->id()));
});
connectBlocks(m_currentBlock, predicate(*tryHeaderBlock));
setCurrentBlock(*tryHeaderBlock);
// Visit everything, except the actual external call.
externalCall->expression().accept(*this);
ASTNode::listAccept(externalCall->arguments(), *this);
// Branch directly to all catch clauses, since in these cases, any effects of the external call are reverted.
for (size_t i = 1; i < clauseBlocks.size(); ++i)
connectBlocks(m_currentBlock, predicate(*clauseBlocks[i]));
// Only now visit the actual call to record its effects and connect to the success clause.
endVisit(*externalCall);
if (_tryStatement.successClause()->parameters())
expressionToTupleAssignment(_tryStatement.successClause()->parameters()->parameters(), *externalCall);
connectBlocks(m_currentBlock, predicate(*clauseBlocks[0]));
for (size_t i = 0; i < clauses.size(); ++i)
{
setCurrentBlock(*clauseBlocks[i]);
clauses[i]->accept(*this);
connectBlocks(m_currentBlock, predicate(*afterTryBlock));
}
setCurrentBlock(*afterTryBlock);
return false;
}
void CHC::pushInlineFrame(CallableDeclaration const& _callable)
{
m_returnDests.push_back(createBlock(&_callable, PredicateType::FunctionBlock, "return_"));
}
void CHC::popInlineFrame(CallableDeclaration const& _callable)
{
solAssert(!m_returnDests.empty(), "");
auto const& ret = *m_returnDests.back();
solAssert(ret.programNode() == &_callable, "");
connectBlocks(m_currentBlock, predicate(ret));
setCurrentBlock(ret);
m_returnDests.pop_back();
}
void CHC::visitAssert(FunctionCall const& _funCall)
{
auto const& args = _funCall.arguments();
solAssert(args.size() == 1, "");
solAssert(args.front()->annotation().type->category() == Type::Category::Bool, "");
solAssert(m_currentContract, "");
solAssert(m_currentFunction, "");
auto errorCondition = !m_context.expression(*args.front())->currentValue();
verificationTargetEncountered(&_funCall, VerificationTargetType::Assert, errorCondition);
}
void CHC::visitPublicGetter(FunctionCall const& _funCall)
{
createExpr(_funCall);
if (encodeExternalCallsAsTrusted())
{
auto const& access = dynamic_cast<MemberAccess const&>(_funCall.expression());
auto const& contractType = dynamic_cast<ContractType const&>(*access.expression().annotation().type);
state().writeStateVars(*m_currentContract, state().thisAddress());
state().readStateVars(contractType.contractDefinition(), expr(access.expression()));
}
SMTEncoder::visitPublicGetter(_funCall);
}
void CHC::visitAddMulMod(FunctionCall const& _funCall)
{
solAssert(_funCall.arguments().at(2), "");
verificationTargetEncountered(&_funCall, VerificationTargetType::DivByZero, expr(*_funCall.arguments().at(2)) == 0);
SMTEncoder::visitAddMulMod(_funCall);
}
void CHC::visitDeployment(FunctionCall const& _funCall)
{
if (!encodeExternalCallsAsTrusted())
{
SMTEncoder::endVisit(_funCall);
unknownFunctionCall(_funCall);
return;
}
auto [callExpr, callOptions] = functionCallExpression(_funCall);
auto funType = dynamic_cast<FunctionType const*>(callExpr->annotation().type);
ContractDefinition const* contract =
&dynamic_cast<ContractType const&>(*funType->returnParameterTypes().front()).contractDefinition();
// copy state variables from m_currentContract to state.storage.
state().writeStateVars(*m_currentContract, state().thisAddress());
errorFlag().increaseIndex();
Expression const* value = valueOption(callOptions);
if (value)
decreaseBalanceFromOptionsValue(*value);
auto originalTx = state().tx();
newTxConstraints(value);
auto prevThisAddr = state().thisAddress();
auto newAddr = state().newThisAddress();
if (auto constructor = contract->constructor())
{
auto const& args = _funCall.sortedArguments();
auto const& params = constructor->parameters();
solAssert(args.size() == params.size(), "");
for (auto [arg, param]: ranges::zip_view(args, params))
m_context.addAssertion(expr(*arg, param->type()) == m_context.variable(*param)->currentValue());
}
for (auto var: stateVariablesIncludingInheritedAndPrivate(*contract))
m_context.variable(*var)->increaseIndex();
Predicate const& constructorSummary = *m_constructorSummaries.at(contract);
m_context.addAssertion(smt::constructorCall(constructorSummary, m_context, false));
solAssert(m_errorDest, "");
connectBlocks(
m_currentBlock,
predicate(*m_errorDest),
errorFlag().currentValue() > 0
);
m_context.addAssertion(errorFlag().currentValue() == 0);
m_context.addAssertion(state().newThisAddress() == prevThisAddr);
// copy state variables from state.storage to m_currentContract.
state().readStateVars(*m_currentContract, state().thisAddress());
state().newTx();
m_context.addAssertion(originalTx == state().tx());
defineExpr(_funCall, newAddr);
}
void CHC::internalFunctionCall(
FunctionDefinition const* _funDef,
std::optional<Expression const*> _boundArgumentCall,
FunctionType const* _funType,
std::vector<Expression const*> const& _arguments,
smtutil::Expression _contractAddressValue
)
{
solAssert(m_currentContract, "");
solAssert(_funType, "");
if (_funDef)
{
if (m_currentFunction && !m_currentFunction->isConstructor())
m_callGraph[m_currentFunction].insert(_funDef);
else
m_callGraph[m_currentContract].insert(_funDef);
}
m_context.addAssertion(predicate(_funDef, _boundArgumentCall, _funType, _arguments, _contractAddressValue));
solAssert(m_errorDest, "");
connectBlocks(
m_currentBlock,
predicate(*m_errorDest),
errorFlag().currentValue() > 0 && currentPathConditions()
);
m_context.addAssertion(smtutil::Expression::implies(currentPathConditions(), errorFlag().currentValue() == 0));
m_context.addAssertion(errorFlag().increaseIndex() == 0);
}
void CHC::internalFunctionCall(FunctionCall const& _funCall)
{
solAssert(m_currentContract, "");
auto funDef = functionCallToDefinition(_funCall, currentScopeContract(), m_currentContract);
if (funDef)
{
if (m_currentFunction && !m_currentFunction->isConstructor())
m_callGraph[m_currentFunction].insert(funDef);
else
m_callGraph[m_currentContract].insert(funDef);
}
Expression const* calledExpr = &_funCall.expression();
auto funType = dynamic_cast<FunctionType const*>(calledExpr->annotation().type);
std::vector<Expression const*> arguments;
for (auto& arg: _funCall.sortedArguments())
arguments.push_back(&(*arg));
std::optional<Expression const*> boundArgumentCall =
funType->hasBoundFirstArgument() ? std::make_optional(calledExpr) : std::nullopt;
internalFunctionCall(funDef, boundArgumentCall, funType, arguments, contractAddressValue(_funCall));
}
void CHC::addNondetCalls(ContractDefinition const& _contract)
{
for (auto var: _contract.stateVariables())
if (auto contractType = dynamic_cast<ContractType const*>(var->type()))
{
auto const& symbVar = m_context.variable(*var);
m_context.addAssertion(symbVar->currentValue() == symbVar->valueAtIndex(0));
nondetCall(contractType->contractDefinition(), *var);
}
}
void CHC::nondetCall(ContractDefinition const& _contract, VariableDeclaration const& _var)
{
auto address = m_context.variable(_var)->currentValue();
// Load the called contract's state variables from the global state.
state().readStateVars(_contract, address);
m_context.addAssertion(state().state() == state().state(0));
auto preCallState = std::vector<smtutil::Expression>{state().state()} + currentStateVariables(_contract);
state().newState();
for (auto const* var: _contract.stateVariables())
m_context.variable(*var)->increaseIndex();
Predicate const& callPredicate = *createSymbolicBlock(
nondetInterfaceSort(_contract, state()),
"nondet_call_" + uniquePrefix(),
PredicateType::FunctionSummary,
&_var,
m_currentContract
);
auto postCallState = std::vector<smtutil::Expression>{state().state()} + currentStateVariables(_contract);
std::vector<smtutil::Expression> stateExprs = commonStateExpressions(errorFlag().increaseIndex(), address);
auto nondet = (*m_nondetInterfaces.at(&_contract))(stateExprs + preCallState + postCallState);
auto nondetCall = callPredicate(stateExprs + preCallState + postCallState);
addRule(smtutil::Expression::implies(nondet, nondetCall), nondetCall.name);
m_context.addAssertion(nondetCall);
// Load the called contract's state variables into the global state.
state().writeStateVars(_contract, address);
}
void CHC::externalFunctionCall(FunctionCall const& _funCall)
{
/// In external function calls we do not add a "predicate call"
/// because we do not trust their function body anyway,
/// so we just add the nondet_interface predicate.
solAssert(m_currentContract, "");
auto [callExpr, callOptions] = functionCallExpression(_funCall);
FunctionType const& funType = dynamic_cast<FunctionType const&>(*callExpr->annotation().type);
auto kind = funType.kind();
solAssert(
kind == FunctionType::Kind::External ||
kind == FunctionType::Kind::BareCall ||
kind == FunctionType::Kind::BareStaticCall,
""
);