mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
289 lines
11 KiB
C++
289 lines
11 KiB
C++
/*
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This file is part of solidity.
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solidity is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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solidity is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with solidity. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* Model checker based on Constrained Horn Clauses.
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*
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* A Solidity contract's CFG is encoded into a system of Horn clauses where
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* each block has a predicate and edges are rules.
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*
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* The entry block is the constructor which has no in-edges.
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* The constructor has one out-edge to an artificial block named _Interface_
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* which has in/out-edges from/to all public functions.
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*
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* Loop invariants for Interface -> Interface' are state invariants.
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*/
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#pragma once
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#include <libsolidity/formal/SMTEncoder.h>
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#include <libsolidity/interface/ReadFile.h>
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#include <libsmtutil/CHCSolverInterface.h>
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#include <set>
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namespace solidity::frontend
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{
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class CHC: public SMTEncoder
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{
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public:
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CHC(
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smt::EncodingContext& _context,
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langutil::ErrorReporter& _errorReporter,
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std::map<util::h256, std::string> const& _smtlib2Responses,
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ReadCallback::Callback const& _smtCallback,
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smtutil::SMTSolverChoice _enabledSolvers
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);
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void analyze(SourceUnit const& _sources);
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std::set<Expression const*> const& safeAssertions() const { return m_safeAssertions; }
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/// This is used if the Horn solver is not directly linked into this binary.
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/// @returns a list of inputs to the Horn solver that were not part of the argument to
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/// the constructor.
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std::vector<std::string> unhandledQueries() const;
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private:
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/// Visitor functions.
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//@{
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bool visit(ContractDefinition const& _node) override;
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void endVisit(ContractDefinition const& _node) override;
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bool visit(FunctionDefinition const& _node) override;
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void endVisit(FunctionDefinition const& _node) override;
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bool visit(IfStatement const& _node) override;
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bool visit(WhileStatement const&) override;
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bool visit(ForStatement const&) override;
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void endVisit(FunctionCall const& _node) override;
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void endVisit(Break const& _node) override;
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void endVisit(Continue const& _node) override;
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void visitAssert(FunctionCall const& _funCall);
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void internalFunctionCall(FunctionCall const& _funCall);
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void unknownFunctionCall(FunctionCall const& _funCall);
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void makeArrayPopVerificationTarget(FunctionCall const& _arrayPop) override;
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//@}
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struct IdCompare
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{
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bool operator()(ASTNode const* lhs, ASTNode const* rhs) const
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{
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return lhs->id() < rhs->id();
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}
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};
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/// Helpers.
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//@{
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void resetSourceAnalysis();
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void resetContractAnalysis();
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void eraseKnowledge();
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void clearIndices(ContractDefinition const* _contract, FunctionDefinition const* _function = nullptr) override;
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bool shouldVisit(FunctionDefinition const& _function) const;
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void setCurrentBlock(smt::SymbolicFunctionVariable const& _block, std::vector<smtutil::Expression> const* _arguments = nullptr);
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std::set<Expression const*, IdCompare> transactionAssertions(ASTNode const* _txRoot);
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static std::vector<VariableDeclaration const*> stateVariablesIncludingInheritedAndPrivate(ContractDefinition const& _contract);
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//@}
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/// Sort helpers.
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//@{
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static std::vector<smtutil::SortPointer> stateSorts(ContractDefinition const& _contract);
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smtutil::SortPointer constructorSort();
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smtutil::SortPointer interfaceSort();
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static smtutil::SortPointer interfaceSort(ContractDefinition const& _const);
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smtutil::SortPointer arity0FunctionSort();
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smtutil::SortPointer sort(FunctionDefinition const& _function);
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smtutil::SortPointer sort(ASTNode const* _block);
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/// @returns the sort of a predicate that represents the summary of _function in the scope of _contract.
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/// The _contract is also needed because the same function might be in many contracts due to inheritance,
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/// where the sort changes because the set of state variables might change.
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static smtutil::SortPointer summarySort(FunctionDefinition const& _function, ContractDefinition const& _contract);
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//@}
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/// Predicate helpers.
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//@{
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/// @returns a new block of given _sort and _name.
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std::unique_ptr<smt::SymbolicFunctionVariable> createSymbolicBlock(smtutil::SortPointer _sort, std::string const& _name);
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/// Creates summary predicates for all functions of all contracts
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/// in a given _source.
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void defineInterfacesAndSummaries(SourceUnit const& _source);
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/// Genesis predicate.
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smtutil::Expression genesis() { return (*m_genesisPredicate)({}); }
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/// Interface predicate over current variables.
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smtutil::Expression interface();
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smtutil::Expression interface(ContractDefinition const& _contract);
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/// Error predicate over current variables.
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smtutil::Expression error();
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smtutil::Expression error(unsigned _idx);
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/// Creates a block for the given _node.
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std::unique_ptr<smt::SymbolicFunctionVariable> createBlock(ASTNode const* _node, std::string const& _prefix = "");
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/// Creates a call block for the given function _function from contract _contract.
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/// The contract is needed here because of inheritance.
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std::unique_ptr<smt::SymbolicFunctionVariable> createSummaryBlock(FunctionDefinition const& _function, ContractDefinition const& _contract);
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/// Creates a new error block to be used by an assertion.
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/// Also registers the predicate.
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void createErrorBlock();
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void connectBlocks(smtutil::Expression const& _from, smtutil::Expression const& _to, smtutil::Expression const& _constraints = smtutil::Expression(true));
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/// @returns the symbolic values of the state variables at the beginning
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/// of the current transaction.
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std::vector<smtutil::Expression> initialStateVariables();
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std::vector<smtutil::Expression> stateVariablesAtIndex(int _index);
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std::vector<smtutil::Expression> stateVariablesAtIndex(int _index, ContractDefinition const& _contract);
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/// @returns the current symbolic values of the current state variables.
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std::vector<smtutil::Expression> currentStateVariables();
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/// @returns the current symbolic values of the current function's
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/// input and output parameters.
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std::vector<smtutil::Expression> currentFunctionVariables();
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/// @returns the same as currentFunctionVariables plus
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/// local variables.
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std::vector<smtutil::Expression> currentBlockVariables();
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/// @returns the predicate name for a given node.
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std::string predicateName(ASTNode const* _node, ContractDefinition const* _contract = nullptr);
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/// @returns a predicate application over the current scoped variables.
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smtutil::Expression predicate(smt::SymbolicFunctionVariable const& _block);
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/// @returns a predicate application over @param _arguments.
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smtutil::Expression predicate(smt::SymbolicFunctionVariable const& _block, std::vector<smtutil::Expression> const& _arguments);
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/// @returns the summary predicate for the called function.
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smtutil::Expression predicate(FunctionCall const& _funCall);
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/// @returns a predicate that defines a constructor summary.
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smtutil::Expression summary(ContractDefinition const& _contract);
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/// @returns a predicate that defines a function summary.
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smtutil::Expression summary(FunctionDefinition const& _function);
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//@}
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/// Solver related.
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//@{
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/// Adds Horn rule to the solver.
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void addRule(smtutil::Expression const& _rule, std::string const& _ruleName);
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/// @returns <true, empty> if query is unsatisfiable (safe).
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/// @returns <false, model> otherwise.
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std::pair<smtutil::CheckResult, std::vector<std::string>> query(smtutil::Expression const& _query, langutil::SourceLocation const& _location);
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void addVerificationTarget(ASTNode const* _scope, VerificationTarget::Type _type, smtutil::Expression _from, smtutil::Expression _constraints, smtutil::Expression _errorId);
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void addAssertVerificationTarget(ASTNode const* _scope, smtutil::Expression _from, smtutil::Expression _constraints, smtutil::Expression _errorId);
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void addArrayPopVerificationTarget(ASTNode const* _scope, smtutil::Expression _errorId);
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//@}
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/// Misc.
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//@{
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/// Returns a prefix to be used in a new unique block name
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/// and increases the block counter.
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std::string uniquePrefix();
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//@}
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/// Predicates.
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//@{
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/// Genesis predicate.
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std::unique_ptr<smt::SymbolicFunctionVariable> m_genesisPredicate;
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/// Implicit constructor predicate.
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/// Explicit constructors are handled as functions.
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std::unique_ptr<smt::SymbolicFunctionVariable> m_implicitConstructorPredicate;
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/// Constructor summary predicate, exists after the constructor
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/// (implicit or explicit) and before the interface.
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std::unique_ptr<smt::SymbolicFunctionVariable> m_constructorSummaryPredicate;
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/// Artificial Interface predicate.
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/// Single entry block for all functions.
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std::map<ContractDefinition const*, std::unique_ptr<smt::SymbolicFunctionVariable>> m_interfaces;
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/// Artificial Error predicate.
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/// Single error block for all assertions.
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std::unique_ptr<smt::SymbolicFunctionVariable> m_errorPredicate;
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/// Function predicates.
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std::map<ContractDefinition const*, std::map<FunctionDefinition const*, std::unique_ptr<smt::SymbolicFunctionVariable>>> m_summaries;
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smt::SymbolicIntVariable m_error{
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TypeProvider::uint256(),
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TypeProvider::uint256(),
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"error",
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m_context
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};
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//@}
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/// Variables.
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//@{
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/// State variables sorts.
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/// Used by all predicates.
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std::vector<smtutil::SortPointer> m_stateSorts;
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/// State variables.
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/// Used to create all predicates.
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std::vector<VariableDeclaration const*> m_stateVariables;
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//@}
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/// Verification targets.
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//@{
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struct CHCVerificationTarget: VerificationTarget
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{
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smtutil::Expression errorId;
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};
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std::map<ASTNode const*, CHCVerificationTarget, IdCompare> m_verificationTargets;
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/// Assertions proven safe.
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std::set<Expression const*> m_safeAssertions;
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/// Targets proven unsafe.
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std::set<ASTNode const*> m_unsafeTargets;
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//@}
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/// Control-flow.
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//@{
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FunctionDefinition const* m_currentFunction = nullptr;
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std::map<ASTNode const*, std::set<ASTNode const*, IdCompare>, IdCompare> m_callGraph;
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std::map<ASTNode const*, std::set<Expression const*>, IdCompare> m_functionAssertions;
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/// The current block.
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smtutil::Expression m_currentBlock = smtutil::Expression(true);
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/// Counter to generate unique block names.
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unsigned m_blockCounter = 0;
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/// Whether a function call was seen in the current scope.
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bool m_unknownFunctionCallSeen = false;
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/// Block where a loop break should go to.
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smt::SymbolicFunctionVariable const* m_breakDest = nullptr;
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/// Block where a loop continue should go to.
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smt::SymbolicFunctionVariable const* m_continueDest = nullptr;
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//@}
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/// CHC solver.
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std::unique_ptr<smtutil::CHCSolverInterface> m_interface;
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/// ErrorReporter that comes from CompilerStack.
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langutil::ErrorReporter& m_outerErrorReporter;
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/// SMT solvers that are chosen at runtime.
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smtutil::SMTSolverChoice m_enabledSolvers;
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};
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}
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