/********************* */ /*! \file theory_engine.h ** \verbatim ** Original author: Morgan Deters ** Major contributors: Andrew Reynolds, Dejan Jovanovic ** Minor contributors (to current version): Christopher L. Conway, Francois Bobot, Kshitij Bansal, Clark Barrett, Liana Hadarean, Tim King ** This file is part of the CVC4 project. ** Copyright (c) 2009-2014 New York University and The University of Iowa ** See the file COPYING in the top-level source directory for licensing ** information.\endverbatim ** ** \brief The theory engine ** ** The theory engine. **/ #include "cvc4_private.h" #ifndef __CVC4__THEORY_ENGINE_H #define __CVC4__THEORY_ENGINE_H #include #include #include #include "base/cvc4_assert.h" #include "context/cdhashset.h" #include "expr/node.h" #include "options/options.h" #include "options/smt_options.h" #include "prop/prop_engine.h" #include "smt/smt_globals.h" #include "smt_util/command.h" #include "theory/atom_requests.h" #include "theory/bv/bv_to_bool.h" #include "theory/interrupted.h" #include "theory/quantifiers/quant_conflict_find.h" #include "theory/rewriter.h" #include "theory/shared_terms_database.h" #include "theory/sort_inference.h" #include "theory/substitutions.h" #include "theory/term_registration_visitor.h" #include "theory/theory.h" #include "theory/uf/equality_engine.h" #include "theory/valuation.h" #include "util/statistics_registry.h" #include "util/unsafe_interrupt_exception.h" namespace CVC4 { class ResourceManager; /** * A pair of a theory and a node. This is used to mark the flow of * propagations between theories. */ struct NodeTheoryPair { Node node; theory::TheoryId theory; size_t timestamp; NodeTheoryPair(TNode node, theory::TheoryId theory, size_t timestamp) : node(node), theory(theory), timestamp(timestamp) {} NodeTheoryPair() : theory(theory::THEORY_LAST) {} // Comparison doesn't take into account the timestamp bool operator == (const NodeTheoryPair& pair) const { return node == pair.node && theory == pair.theory; } };/* struct NodeTheoryPair */ struct NodeTheoryPairHashFunction { NodeHashFunction hashFunction; // Hash doesn't take into account the timestamp size_t operator()(const NodeTheoryPair& pair) const { return hashFunction(pair.node)*0x9e3779b9 + pair.theory; } };/* struct NodeTheoryPairHashFunction */ /* Forward declarations */ namespace theory { class TheoryModel; class TheoryEngineModelBuilder; class ITEUtilities; namespace eq { class EqualityEngine; }/* CVC4::theory::eq namespace */ namespace quantifiers { class TermDb; } class EntailmentCheckParameters; class EntailmentCheckSideEffects; }/* CVC4::theory namespace */ class DecisionEngine; class RemoveITE; class UnconstrainedSimplifier; /** * This is essentially an abstraction for a collection of theories. A * TheoryEngine provides services to a PropEngine, making various * T-solvers look like a single unit to the propositional part of * CVC4. */ class TheoryEngine { /** Shared terms database can use the internals notify the theories */ friend class SharedTermsDatabase; friend class theory::quantifiers::TermDb; /** Associated PropEngine engine */ prop::PropEngine* d_propEngine; /** Access to decision engine */ DecisionEngine* d_decisionEngine; /** Our context */ context::Context* d_context; /** Our user context */ context::UserContext* d_userContext; /** * A table of from theory IDs to theory pointers. Never use this table * directly, use theoryOf() instead. */ theory::Theory* d_theoryTable[theory::THEORY_LAST]; /** * A collection of theories that are "active" for the current run. * This set is provided by the user (as a logic string, say, in SMT-LIBv2 * format input), or else by default it's all-inclusive. This is important * because we can optimize for single-theory runs (no sharing), can reduce * the cost of walking the DAG on registration, etc. */ const LogicInfo& d_logicInfo; /** * The database of shared terms. */ SharedTermsDatabase d_sharedTerms; /** * Master equality engine, to share with theories. */ theory::eq::EqualityEngine* d_masterEqualityEngine; /** notify class for master equality engine */ class NotifyClass : public theory::eq::EqualityEngineNotify { TheoryEngine& d_te; public: NotifyClass(TheoryEngine& te): d_te(te) {} bool eqNotifyTriggerEquality(TNode equality, bool value) { return true; } bool eqNotifyTriggerPredicate(TNode predicate, bool value) { return true; } bool eqNotifyTriggerTermEquality(theory::TheoryId tag, TNode t1, TNode t2, bool value) { return true; } void eqNotifyConstantTermMerge(TNode t1, TNode t2) {} void eqNotifyNewClass(TNode t) { d_te.eqNotifyNewClass(t); } void eqNotifyPreMerge(TNode t1, TNode t2) { d_te.eqNotifyPreMerge(t1, t2); } void eqNotifyPostMerge(TNode t1, TNode t2) { d_te.eqNotifyPostMerge(t1, t2); } void eqNotifyDisequal(TNode t1, TNode t2, TNode reason) { d_te.eqNotifyDisequal(t1, t2, reason); } };/* class TheoryEngine::NotifyClass */ NotifyClass d_masterEENotify; /** * notification methods */ void eqNotifyNewClass(TNode t); void eqNotifyPreMerge(TNode t1, TNode t2); void eqNotifyPostMerge(TNode t1, TNode t2); void eqNotifyDisequal(TNode t1, TNode t2, TNode reason); /** * The quantifiers engine */ theory::QuantifiersEngine* d_quantEngine; /** * Default model object */ theory::TheoryModel* d_curr_model; /** * Model builder object */ theory::TheoryEngineModelBuilder* d_curr_model_builder; typedef std::hash_map NodeMap; typedef std::hash_map TNodeMap; /** * Cache for theory-preprocessing of assertions */ NodeMap d_ppCache; /** * Used for "missed-t-propagations" dumping mode only. A set of all * theory-propagable literals. */ context::CDList d_possiblePropagations; /** * Used for "missed-t-propagations" dumping mode only. A * context-dependent set of those theory-propagable literals that * have been propagated. */ context::CDHashSet d_hasPropagated; /** * Statistics for a particular theory. */ class Statistics { static std::string mkName(std::string prefix, theory::TheoryId theory, std::string suffix) { std::stringstream ss; ss << prefix << theory << suffix; return ss.str(); } public: IntStat conflicts, propagations, lemmas, requirePhase, flipDecision, restartDemands; Statistics(theory::TheoryId theory); ~Statistics(); };/* class TheoryEngine::Statistics */ /** * An output channel for Theory that passes messages * back to a TheoryEngine. */ class EngineOutputChannel : public theory::OutputChannel { friend class TheoryEngine; /** * The theory engine we're communicating with. */ TheoryEngine* d_engine; /** * The statistics of the theory interractions. */ Statistics d_statistics; /** * The theory owning this chanell. */ theory::TheoryId d_theory; public: EngineOutputChannel(TheoryEngine* engine, theory::TheoryId theory) : d_engine(engine), d_statistics(theory), d_theory(theory) { } void safePoint(uint64_t ammount) throw(theory::Interrupted, UnsafeInterruptException, AssertionException) { spendResource(ammount); if (d_engine->d_interrupted) { throw theory::Interrupted(); } } void conflict(TNode conflictNode, Proof* pf = NULL) throw(AssertionException, UnsafeInterruptException) { Trace("theory::conflict") << "EngineOutputChannel<" << d_theory << ">::conflict(" << conflictNode << ")" << std::endl; Assert(pf == NULL); // theory shouldn't be producing proofs yet ++ d_statistics.conflicts; d_engine->d_outputChannelUsed = true; d_engine->conflict(conflictNode, d_theory); } bool propagate(TNode literal) throw(AssertionException, UnsafeInterruptException) { Trace("theory::propagate") << "EngineOutputChannel<" << d_theory << ">::propagate(" << literal << ")" << std::endl; ++ d_statistics.propagations; d_engine->d_outputChannelUsed = true; return d_engine->propagate(literal, d_theory); } theory::LemmaStatus lemma(TNode lemma, ProofRule rule, bool removable = false, bool preprocess = false, bool sendAtoms = false) throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) { Trace("theory::lemma") << "EngineOutputChannel<" << d_theory << ">::lemma(" << lemma << ")" << std::endl; ++ d_statistics.lemmas; d_engine->d_outputChannelUsed = true; return d_engine->lemma(lemma, rule, false, removable, preprocess, sendAtoms ? d_theory: theory::THEORY_LAST); } theory::LemmaStatus splitLemma(TNode lemma, bool removable = false) throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) { Trace("theory::lemma") << "EngineOutputChannel<" << d_theory << ">::lemma(" << lemma << ")" << std::endl; ++ d_statistics.lemmas; d_engine->d_outputChannelUsed = true; return d_engine->lemma(lemma, RULE_SPLIT, false, removable, false, d_theory); } void demandRestart() throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) { NodeManager* curr = NodeManager::currentNM(); Node restartVar = curr->mkSkolem("restartVar", curr->booleanType(), "A boolean variable asserted to be true to force a restart"); Trace("theory::restart") << "EngineOutputChannel<" << d_theory << ">::restart(" << restartVar << ")" << std::endl; ++ d_statistics.restartDemands; lemma(restartVar, RULE_INVALID, true); } void requirePhase(TNode n, bool phase) throw(theory::Interrupted, AssertionException, UnsafeInterruptException) { Debug("theory") << "EngineOutputChannel::requirePhase(" << n << ", " << phase << ")" << std::endl; ++ d_statistics.requirePhase; d_engine->d_propEngine->requirePhase(n, phase); } bool flipDecision() throw(theory::Interrupted, AssertionException, UnsafeInterruptException) { Debug("theory") << "EngineOutputChannel::flipDecision()" << std::endl; ++ d_statistics.flipDecision; return d_engine->d_propEngine->flipDecision(); } void setIncomplete() throw(AssertionException, UnsafeInterruptException) { Trace("theory") << "TheoryEngine::setIncomplete()" << std::endl; d_engine->setIncomplete(d_theory); } void spendResource(unsigned ammount) throw(UnsafeInterruptException) { d_engine->spendResource(ammount); } void handleUserAttribute( const char* attr, theory::Theory* t ){ d_engine->handleUserAttribute( attr, t ); } };/* class TheoryEngine::EngineOutputChannel */ /** * Output channels for individual theories. */ EngineOutputChannel* d_theoryOut[theory::THEORY_LAST]; /** * Are we in conflict. */ context::CDO d_inConflict; /** * Called by the theories to notify of a conflict. */ void conflict(TNode conflict, theory::TheoryId theoryId); /** * Debugging flag to ensure that shutdown() is called before the * destructor. */ bool d_hasShutDown; /** * True if a theory has notified us of incompleteness (at this * context level or below). */ context::CDO d_incomplete; /** * Called by the theories to notify that the current branch is incomplete. */ void setIncomplete(theory::TheoryId theory) { d_incomplete = true; } /** * Mapping of propagations from recievers to senders. */ typedef context::CDHashMap PropagationMap; PropagationMap d_propagationMap; /** * Timestamp of propagations */ context::CDO d_propagationMapTimestamp; /** * Literals that are propagated by the theory. Note that these are TNodes. * The theory can only propagate nodes that have an assigned literal in the * SAT solver and are hence referenced in the SAT solver. */ context::CDList d_propagatedLiterals; /** * The index of the next literal to be propagated by a theory. */ context::CDO d_propagatedLiteralsIndex; /** * Called by the output channel to propagate literals and facts * @return false if immediate conflict */ bool propagate(TNode literal, theory::TheoryId theory); /** * Internal method to call the propagation routines and collect the * propagated literals. */ void propagate(theory::Theory::Effort effort); /** * Called by the output channel to request decisions "as soon as * possible." */ void propagateAsDecision(TNode literal, theory::TheoryId theory); /** * A variable to mark if we added any lemmas. */ bool d_lemmasAdded; /** * A variable to mark if the OutputChannel was "used" by any theory * since the start of the last check. If it has been, we require * a FULL_EFFORT check before exiting and reporting SAT. * * See the documentation for the needCheck() function, below. */ bool d_outputChannelUsed; /** Atom requests from lemmas */ AtomRequests d_atomRequests; /** * Adds a new lemma, returning its status. * @param node the lemma * @param negated should the lemma be asserted negated * @param removable can the lemma be remove (restrictions apply) * @param needAtoms if not THEORY_LAST, then */ theory::LemmaStatus lemma(TNode node, ProofRule rule, bool negated, bool removable, bool preprocess, theory::TheoryId atomsTo); /** Enusre that the given atoms are send to the given theory */ void ensureLemmaAtoms(const std::vector& atoms, theory::TheoryId theory); RemoveITE& d_iteRemover; /** sort inference module */ SortInference d_sortInfer; /** Time spent in theory combination */ TimerStat d_combineTheoriesTime; Node d_true; Node d_false; /** Whether we were just interrupted (or not) */ bool d_interrupted; ResourceManager* d_resourceManager; /** Container for misc. globals. */ SmtGlobals* d_globals; public: /** Constructs a theory engine */ TheoryEngine(context::Context* context, context::UserContext* userContext, RemoveITE& iteRemover, const LogicInfo& logic, SmtGlobals* globals); /** Destroys a theory engine */ ~TheoryEngine(); void interrupt() throw(ModalException); /** * "Spend" a resource during a search or preprocessing. */ void spendResource(unsigned ammount); /** * Adds a theory. Only one theory per TheoryId can be present, so if * there is another theory it will be deleted. */ template inline void addTheory(theory::TheoryId theoryId) { Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL); d_theoryOut[theoryId] = new EngineOutputChannel(this, theoryId); d_theoryTable[theoryId] = new TheoryClass(d_context, d_userContext, *d_theoryOut[theoryId], theory::Valuation(this), d_logicInfo, d_globals); } inline void setPropEngine(prop::PropEngine* propEngine) { Assert(d_propEngine == NULL); d_propEngine = propEngine; } inline void setDecisionEngine(DecisionEngine* decisionEngine) { Assert(d_decisionEngine == NULL); d_decisionEngine = decisionEngine; } /** Called when all initialization of options/logic is done */ void finishInit(); /** * Get a pointer to the underlying propositional engine. */ inline prop::PropEngine* getPropEngine() const { return d_propEngine; } /** * Get a pointer to the underlying sat context. */ inline context::Context* getSatContext() const { return d_context; } /** * Get a pointer to the underlying user context. */ inline context::Context* getUserContext() const { return d_userContext; } /** * Get a pointer to the underlying quantifiers engine. */ theory::QuantifiersEngine* getQuantifiersEngine() const { return d_quantEngine; } private: /** * Helper for preprocess */ Node ppTheoryRewrite(TNode term); /** * Queue of nodes for pre-registration. */ std::queue d_preregisterQueue; /** * Boolean flag denoting we are in pre-registration. */ bool d_inPreregister; /** * Did the theories get any new facts since the last time we called * check() */ context::CDO d_factsAsserted; /** * Map from equality atoms to theories that would like to be notified about them. */ /** * Assert the formula to the given theory. * @param assertion the assertion to send (not necesserily normalized) * @param original the assertion as it was sent in from the propagating theory * @param toTheoryId the theory to assert to * @param fromTheoryId the theory that sent it */ void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId); /** * Marks a theory propagation from a theory to a theory where a * theory could be the THEORY_SAT_SOLVER for literals coming from * or being propagated to the SAT solver. If the receiving theory * already recieved the literal, the method returns false, otherwise * it returns true. * * @param assertion the normalized assertion being sent * @param originalAssertion the actual assertion that was sent * @param toTheoryId the theory that is on the receiving end * @param fromTheoryId the theory that sent the assertino * @return true if a new assertion, false if theory already got it */ bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId); /** * Computes the explanation by travarsing the propagation graph and * asking relevant theories to explain the propagations. Initially * the explanation vector should contain only the element (node, theory) * where the node is the one to be explained, and the theory is the * theory that sent the literal. */ void getExplanation(std::vector& explanationVector); public: /** * Signal the start of a new round of assertion preprocessing */ void preprocessStart(); /** * Runs theory specific preprocessing on the non-Boolean parts of * the formula. This is only called on input assertions, after ITEs * have been removed. */ Node preprocess(TNode node); /** * Return whether or not we are incomplete (in the current context). */ inline bool isIncomplete() const { return d_incomplete; } /** * Returns true if we need another round of checking. If this * returns true, check(FULL_EFFORT) _must_ be called by the * propositional layer before reporting SAT. * * This is especially necessary for incomplete theories that lazily * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning * outputing quantifier instantiations). In such a case, a lemma can * be asserted that is simplified away (perhaps it's already true). * However, we must maintain the invariant that, if a theory uses the * OutputChannel, it implicitly requests that another check(FULL_EFFORT) * be performed before exit, even if no new facts are on its fact queue, * as it might decide to further instantiate some lemmas, precluding * a SAT response. */ inline bool needCheck() const { return d_outputChannelUsed || d_lemmasAdded; } /** * This is called at shutdown time by the SmtEngine, just before * destruction. It is important because there are destruction * ordering issues between PropEngine and Theory. */ void shutdown(); /** * Solve the given literal with a theory that owns it. */ theory::Theory::PPAssertStatus solve(TNode literal, theory::SubstitutionMap& substitutionOut); /** * Preregister a Theory atom with the responsible theory (or * theories). */ void preRegister(TNode preprocessed); /** * Assert the formula to the appropriate theory. * @param node the assertion */ void assertFact(TNode node); /** * Check all (currently-active) theories for conflicts. * @param effort the effort level to use */ void check(theory::Theory::Effort effort); /** * Run the combination framework. */ void combineTheories(); /** * Calls ppStaticLearn() on all theories, accumulating their * combined contributions in the "learned" builder. */ void ppStaticLearn(TNode in, NodeBuilder<>& learned); /** * Calls presolve() on all theories and returns true * if one of the theories discovers a conflict. */ bool presolve(); /** * Calls postsolve() on all theories. */ void postsolve(); /** * Calls notifyRestart() on all active theories. */ void notifyRestart(); void getPropagatedLiterals(std::vector& literals) { for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) { Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl; literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]); } } Node getNextDecisionRequest(); bool properConflict(TNode conflict) const; bool properPropagation(TNode lit) const; bool properExplanation(TNode node, TNode expl) const; /** * Returns an explanation of the node propagated to the SAT solver. */ Node getExplanation(TNode node); /** * collect model info */ void collectModelInfo( theory::TheoryModel* m, bool fullModel ); /** * Get the current model */ theory::TheoryModel* getModel(); /** * Get the model builder */ theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; } /** * Get the theory associated to a given Node. * * @returns the theory, or NULL if the TNode is * of built-in type. */ inline theory::Theory* theoryOf(TNode node) const { return d_theoryTable[theory::Theory::theoryOf(node)]; } /** * Get the theory associated to a the given theory id. * * @returns the theory */ inline theory::Theory* theoryOf(theory::TheoryId theoryId) const { return d_theoryTable[theoryId]; } inline bool isTheoryEnabled(theory::TheoryId theoryId) const { return d_logicInfo.isTheoryEnabled(theoryId); } /** * Returns the equality status of the two terms, from the theory * that owns the domain type. The types of a and b must be the same. */ theory::EqualityStatus getEqualityStatus(TNode a, TNode b); /** * Returns the value that a theory that owns the type of var currently * has (or null if none); */ Node getModelValue(TNode var); /** * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal */ Node ensureLiteral(TNode n); /** * Print all instantiations made by the quantifiers module. */ void printInstantiations( std::ostream& out ); /** * Print solution for synthesis conjectures found by ce_guided_instantiation module */ void printSynthSolution( std::ostream& out ); /** * Forwards an entailment check according to the given theoryOfMode. * See theory.h for documentation on entailmentCheck(). */ std::pair entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL); private: /** Default visitor for pre-registration */ PreRegisterVisitor d_preRegistrationVisitor; /** Visitor for collecting shared terms */ SharedTermsVisitor d_sharedTermsVisitor; /** Dump the assertions to the dump */ void dumpAssertions(const char* tag); /** * A collection of ite preprocessing passes. */ theory::ITEUtilities* d_iteUtilities; /** For preprocessing pass simplifying unconstrained expressions */ UnconstrainedSimplifier* d_unconstrainedSimp; /** For preprocessing pass lifting bit-vectors of size 1 to booleans */ theory::bv::BvToBoolPreprocessor d_bvToBoolPreprocessor; public: void staticInitializeBVOptions(const std::vector& assertions); void ppBvToBool(const std::vector& assertions, std::vector& new_assertions); bool ppBvAbstraction(const std::vector& assertions, std::vector& new_assertions); void mkAckermanizationAsssertions(std::vector& assertions); Node ppSimpITE(TNode assertion); /** Returns false if an assertion simplified to false. */ bool donePPSimpITE(std::vector& assertions); void ppUnconstrainedSimp(std::vector& assertions); SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; } theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; } RemoveITE* getIteRemover() { return &d_iteRemover; } SortInference* getSortInference() { return &d_sortInfer; } /** Prints the assertions to the debug stream */ void printAssertions(const char* tag); private: std::map< std::string, std::vector< theory::Theory* > > d_attr_handle; public: /** * Set user attribute. * This function is called when an attribute is set by a user. In SMT-LIBv2 this is done * via the syntax (! n :attr) */ void setUserAttribute(const std::string& attr, Node n, std::vector node_values, std::string str_value); /** * Handle user attribute. * Associates theory t with the attribute attr. Theory t will be * notified whenever an attribute of name attr is set. */ void handleUserAttribute(const char* attr, theory::Theory* t); /** * Check that the theory assertions are satisfied in the model. * This function is called from the smt engine's checkModel routine. */ void checkTheoryAssertionsWithModel(); private: IntStat d_arithSubstitutionsAdded; };/* class TheoryEngine */ }/* CVC4 namespace */ #endif /* __CVC4__THEORY_ENGINE_H */