src/theory/theory_engine.h

   1 /*********************                                                        */
   2 /*! \file theory_engine.h
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Dejan Jovanovic, Andrew Reynolds, Morgan Deters
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2020 by the authors listed in the file AUTHORS
   8  ** in the top-level source directory) and their institutional affiliations.
   9  ** All rights reserved.  See the file COPYING in the top-level source
  10  ** directory for licensing information.\endverbatim
  11  **
  12  ** \brief The theory engine
  13  **
  14  ** The theory engine.
  15  **/
  16
  17 #include "cvc4_private.h"
  18
  19 #ifndef CVC4__THEORY_ENGINE_H
  20 #define CVC4__THEORY_ENGINE_H
  21
  22 #include <deque>
  23 #include <memory>
  24 #include <set>
  25 #include <unordered_map>
  26 #include <utility>
  27 #include <vector>
  28
  29 #include "base/check.h"
  30 #include "context/cdhashset.h"
  31 #include "expr/node.h"
  32 #include "options/options.h"
  33 #include "options/smt_options.h"
  34 #include "options/theory_options.h"
  35 #include "prop/prop_engine.h"
  36 #include "smt/command.h"
  37 #include "theory/atom_requests.h"
  38 #include "theory/engine_output_channel.h"
  39 #include "theory/interrupted.h"
  40 #include "theory/rewriter.h"
  41 #include "theory/shared_terms_database.h"
  42 #include "theory/sort_inference.h"
  43 #include "theory/substitutions.h"
  44 #include "theory/term_registration_visitor.h"
  45 #include "theory/theory.h"
  46 #include "theory/theory_preprocessor.h"
  47 #include "theory/uf/equality_engine.h"
  48 #include "theory/valuation.h"
  49 #include "util/hash.h"
  50 #include "util/resource_manager.h"
  51 #include "util/statistics_registry.h"
  52 #include "util/unsafe_interrupt_exception.h"
  53
  54 namespace CVC4 {
  55
  56 class ResourceManager;
  57 class LemmaProofRecipe;
  58
  59 /**
  60  * A pair of a theory and a node. This is used to mark the flow of
  61  * propagations between theories.
  62  */
  63 struct NodeTheoryPair {
  64   Node d_node;
  65   theory::TheoryId d_theory;
  66   size_t d_timestamp;
  67   NodeTheoryPair(TNode n, theory::TheoryId t, size_t ts = 0)
  68       : d_node(n), d_theory(t), d_timestamp(ts)
  69   {
  70   }
  71   NodeTheoryPair() : d_theory(theory::THEORY_LAST), d_timestamp() {}
  72   // Comparison doesn't take into account the timestamp
  73   bool operator == (const NodeTheoryPair& pair) const {
  74     return d_node == pair.d_node && d_theory == pair.d_theory;
  75   }
  76 };/* struct NodeTheoryPair */
  77
  78 struct NodeTheoryPairHashFunction {
  79   NodeHashFunction hashFunction;
  80   // Hash doesn't take into account the timestamp
  81   size_t operator()(const NodeTheoryPair& pair) const {
  82     uint64_t hash = fnv1a::fnv1a_64(NodeHashFunction()(pair.d_node));
  83     return static_cast<size_t>(fnv1a::fnv1a_64(pair.d_theory, hash));
  84   }
  85 };/* struct NodeTheoryPairHashFunction */
  86
  87
  88 /* Forward declarations */
  89 namespace theory {
  90   class TheoryModel;
  91   class TheoryEngineModelBuilder;
  92   class EqEngineManagerDistributed;
  93
  94   class DecisionManager;
  95   class RelevanceManager;
  96
  97   namespace eq {
  98     class EqualityEngine;
  99   }/* CVC4::theory::eq namespace */
 100
 101   namespace quantifiers {
 102     class TermDb;
 103   }
 104
 105   class EntailmentCheckParameters;
 106   class EntailmentCheckSideEffects;
 107 }/* CVC4::theory namespace */
 108
 109 class RemoveTermFormulas;
 110
 111 /**
 112  * This is essentially an abstraction for a collection of theories.  A
 113  * TheoryEngine provides services to a PropEngine, making various
 114  * T-solvers look like a single unit to the propositional part of
 115  * CVC4.
 116  */
 117 class TheoryEngine {
 118
 119   /** Shared terms database can use the internals notify the theories */
 120   friend class SharedTermsDatabase;
 121   friend class theory::quantifiers::TermDb;
 122   friend class theory::EngineOutputChannel;
 123
 124   /** Associated PropEngine engine */
 125   prop::PropEngine* d_propEngine;
 126
 127   /** Our context */
 128   context::Context* d_context;
 129
 130   /** Our user context */
 131   context::UserContext* d_userContext;
 132
 133   /**
 134    * A table of from theory IDs to theory pointers. Never use this table
 135    * directly, use theoryOf() instead.
 136    */
 137   theory::Theory* d_theoryTable[theory::THEORY_LAST];
 138
 139   /**
 140    * A collection of theories that are "active" for the current run.
 141    * This set is provided by the user (as a logic string, say, in SMT-LIBv2
 142    * format input), or else by default it's all-inclusive.  This is important
 143    * because we can optimize for single-theory runs (no sharing), can reduce
 144    * the cost of walking the DAG on registration, etc.
 145    */
 146   const LogicInfo& d_logicInfo;
 147
 148   /**
 149    * The database of shared terms.
 150    */
 151   SharedTermsDatabase d_sharedTerms;
 152
 153   /**
 154    * The distributed equality manager. This class is responsible for
 155    * configuring the theories of this class for handling equalties
 156    * in a "distributed" fashion, i.e. each theory maintains a unique
 157    * instance of an equality engine. These equality engines are memory
 158    * managed by this class.
 159    */
 160   std::unique_ptr<theory::EqEngineManagerDistributed> d_eeDistributed;
 161
 162   /**
 163    * The quantifiers engine
 164    */
 165   theory::QuantifiersEngine* d_quantEngine;
 166   /**
 167    * The decision manager
 168    */
 169   std::unique_ptr<theory::DecisionManager> d_decManager;
 170   /** The relevance manager */
 171   std::unique_ptr<theory::RelevanceManager> d_relManager;
 172
 173   /**
 174    * Default model object
 175    */
 176   theory::TheoryModel* d_curr_model;
 177   bool d_aloc_curr_model;
 178   /**
 179    * Model builder object
 180    */
 181   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 182   bool d_aloc_curr_model_builder;
 183   /** are we in eager model building mode? (see setEagerModelBuilding). */
 184   bool d_eager_model_building;
 185
 186   typedef std::unordered_map<Node, Node, NodeHashFunction> NodeMap;
 187   typedef std::unordered_map<TNode, Node, TNodeHashFunction> TNodeMap;
 188
 189   /**
 190    * Used for "missed-t-propagations" dumping mode only.  A set of all
 191    * theory-propagable literals.
 192    */
 193   context::CDList<TNode> d_possiblePropagations;
 194
 195   /**
 196    * Used for "missed-t-propagations" dumping mode only.  A
 197    * context-dependent set of those theory-propagable literals that
 198    * have been propagated.
 199    */
 200   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 201
 202   /**
 203    * Output channels for individual theories.
 204    */
 205   theory::EngineOutputChannel* d_theoryOut[theory::THEORY_LAST];
 206
 207   /**
 208    * Are we in conflict.
 209    */
 210   context::CDO<bool> d_inConflict;
 211
 212   /**
 213    * Are we in "SAT mode"? In this state, the user can query for the model.
 214    * This corresponds to the state in Figure 4.1, page 52 of the SMT-LIB
 215    * standard, version 2.6.
 216    */
 217   bool d_inSatMode;
 218
 219   /**
 220    * Called by the theories to notify of a conflict.
 221    */
 222   void conflict(TNode conflict, theory::TheoryId theoryId);
 223
 224   /**
 225    * Debugging flag to ensure that shutdown() is called before the
 226    * destructor.
 227    */
 228   bool d_hasShutDown;
 229
 230   /**
 231    * True if a theory has notified us of incompleteness (at this
 232    * context level or below).
 233    */
 234   context::CDO<bool> d_incomplete;
 235
 236   /**
 237    * Called by the theories to notify that the current branch is incomplete.
 238    */
 239   void setIncomplete(theory::TheoryId theory) {
 240     d_incomplete = true;
 241   }
 242
 243
 244   /**
 245    * Mapping of propagations from recievers to senders.
 246    */
 247   typedef context::CDHashMap<NodeTheoryPair, NodeTheoryPair, NodeTheoryPairHashFunction> PropagationMap;
 248   PropagationMap d_propagationMap;
 249
 250   /**
 251    * Timestamp of propagations
 252    */
 253   context::CDO<size_t> d_propagationMapTimestamp;
 254
 255   /**
 256    * Literals that are propagated by the theory. Note that these are TNodes.
 257    * The theory can only propagate nodes that have an assigned literal in the
 258    * SAT solver and are hence referenced in the SAT solver.
 259    */
 260   context::CDList<TNode> d_propagatedLiterals;
 261
 262   /**
 263    * The index of the next literal to be propagated by a theory.
 264    */
 265   context::CDO<unsigned> d_propagatedLiteralsIndex;
 266
 267   /**
 268    * Called by the output channel to propagate literals and facts
 269    * @return false if immediate conflict
 270    */
 271   bool propagate(TNode literal, theory::TheoryId theory);
 272
 273   /**
 274    * Internal method to call the propagation routines and collect the
 275    * propagated literals.
 276    */
 277   void propagate(theory::Theory::Effort effort);
 278
 279   /**
 280    * A variable to mark if we added any lemmas.
 281    */
 282   bool d_lemmasAdded;
 283
 284   /**
 285    * A variable to mark if the OutputChannel was "used" by any theory
 286    * since the start of the last check.  If it has been, we require
 287    * a FULL_EFFORT check before exiting and reporting SAT.
 288    *
 289    * See the documentation for the needCheck() function, below.
 290    */
 291   bool d_outputChannelUsed;
 292
 293   /** Atom requests from lemmas */
 294   AtomRequests d_atomRequests;
 295
 296   /**
 297    * Adds a new lemma, returning its status.
 298    * @param node the lemma
 299    * @param negated should the lemma be asserted negated
 300    * @param p the properties of the lemma.
 301    */
 302   theory::LemmaStatus lemma(TNode node,
 303                             ProofRule rule,
 304                             bool negated,
 305                             theory::LemmaProperty p,
 306                             theory::TheoryId atomsTo);
 307
 308   /** Enusre that the given atoms are send to the given theory */
 309   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 310
 311   /** sort inference module */
 312   SortInference d_sortInfer;
 313
 314   /** The theory preprocessor */
 315   theory::TheoryPreprocessor d_tpp;
 316
 317   /** Time spent in theory combination */
 318   TimerStat d_combineTheoriesTime;
 319
 320   Node d_true;
 321   Node d_false;
 322
 323   /** Whether we were just interrupted (or not) */
 324   bool d_interrupted;
 325   ResourceManager* d_resourceManager;
 326
 327  public:
 328   /** Constructs a theory engine */
 329   TheoryEngine(context::Context* context,
 330                context::UserContext* userContext,
 331                ResourceManager* rm,
 332                RemoveTermFormulas& iteRemover,
 333                const LogicInfo& logic);
 334
 335   /** Destroys a theory engine */
 336   ~TheoryEngine();
 337
 338   void interrupt();
 339
 340   /** "Spend" a resource during a search or preprocessing.*/
 341   void spendResource(ResourceManager::Resource r);
 342
 343   /**
 344    * Adds a theory. Only one theory per TheoryId can be present, so if
 345    * there is another theory it will be deleted.
 346    */
 347   template <class TheoryClass>
 348   inline void addTheory(theory::TheoryId theoryId)
 349   {
 350     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 351     d_theoryOut[theoryId] = new theory::EngineOutputChannel(this, theoryId);
 352     d_theoryTable[theoryId] = new TheoryClass(d_context,
 353                                               d_userContext,
 354                                               *d_theoryOut[theoryId],
 355                                               theory::Valuation(this),
 356                                               d_logicInfo,
 357                                               nullptr);
 358     theory::Rewriter::registerTheoryRewriter(
 359         theoryId, d_theoryTable[theoryId]->getTheoryRewriter());
 360   }
 361
 362   void setPropEngine(prop::PropEngine* propEngine)
 363   {
 364     d_propEngine = propEngine;
 365   }
 366
 367   /**
 368    * Called when all initialization of options/logic is done, after theory
 369    * objects have been created.
 370    *
 371    * This initializes the quantifiers engine, the "official" equality engines
 372    * of each theory as required, and the model and model builder utilities.
 373    */
 374   void finishInit();
 375
 376   /**
 377    * Get a pointer to the underlying propositional engine.
 378    */
 379   inline prop::PropEngine* getPropEngine() const {
 380     return d_propEngine;
 381   }
 382
 383   /**
 384    * Get a pointer to the underlying sat context.
 385    */
 386   inline context::Context* getSatContext() const {
 387     return d_context;
 388   }
 389
 390   /**
 391    * Get a pointer to the underlying user context.
 392    */
 393   inline context::Context* getUserContext() const {
 394     return d_userContext;
 395   }
 396
 397   /**
 398    * Get a pointer to the underlying quantifiers engine.
 399    */
 400   theory::QuantifiersEngine* getQuantifiersEngine() const {
 401     return d_quantEngine;
 402   }
 403   /**
 404    * Get a pointer to the underlying decision manager.
 405    */
 406   theory::DecisionManager* getDecisionManager() const
 407   {
 408     return d_decManager.get();
 409   }
 410
 411  private:
 412   /**
 413    * Queue of nodes for pre-registration.
 414    */
 415   std::queue<TNode> d_preregisterQueue;
 416
 417   /**
 418    * Boolean flag denoting we are in pre-registration.
 419    */
 420   bool d_inPreregister;
 421
 422   /**
 423    * Did the theories get any new facts since the last time we called
 424    * check()
 425    */
 426   context::CDO<bool> d_factsAsserted;
 427
 428   /**
 429    * Map from equality atoms to theories that would like to be notified about them.
 430    */
 431
 432
 433   /**
 434    * Assert the formula to the given theory.
 435    * @param assertion the assertion to send (not necesserily normalized)
 436    * @param original the assertion as it was sent in from the propagating theory
 437    * @param toTheoryId the theory to assert to
 438    * @param fromTheoryId the theory that sent it
 439    */
 440   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 441
 442   /**
 443    * Marks a theory propagation from a theory to a theory where a
 444    * theory could be the THEORY_SAT_SOLVER for literals coming from
 445    * or being propagated to the SAT solver. If the receiving theory
 446    * already recieved the literal, the method returns false, otherwise
 447    * it returns true.
 448    *
 449    * @param assertion the normalized assertion being sent
 450    * @param originalAssertion the actual assertion that was sent
 451    * @param toTheoryId the theory that is on the receiving end
 452    * @param fromTheoryId the theory that sent the assertion
 453    * @return true if a new assertion, false if theory already got it
 454    */
 455   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 456
 457   /**
 458    * Computes the explanation by travarsing the propagation graph and
 459    * asking relevant theories to explain the propagations. Initially
 460    * the explanation vector should contain only the element (node, theory)
 461    * where the node is the one to be explained, and the theory is the
 462    * theory that sent the literal. The lemmaProofRecipe will contain a list
 463    * of the explanation steps required to produce the original node.
 464    */
 465   void getExplanation(std::vector<NodeTheoryPair>& explanationVector, LemmaProofRecipe* lemmaProofRecipe);
 466
 467 public:
 468
 469   /**
 470    * Signal the start of a new round of assertion preprocessing
 471    */
 472   void preprocessStart();
 473
 474   /**
 475    * Runs theory specific preprocessing on the non-Boolean parts of
 476    * the formula.  This is only called on input assertions, after ITEs
 477    * have been removed.
 478    */
 479   Node preprocess(TNode node);
 480
 481   /** Notify (preprocessed) assertions. */
 482   void notifyPreprocessedAssertions(const std::vector<Node>& assertions);
 483
 484   /** Return whether or not we are incomplete (in the current context). */
 485   inline bool isIncomplete() const { return d_incomplete; }
 486
 487   /**
 488    * Returns true if we need another round of checking.  If this
 489    * returns true, check(FULL_EFFORT) _must_ be called by the
 490    * propositional layer before reporting SAT.
 491    *
 492    * This is especially necessary for incomplete theories that lazily
 493    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 494    * outputing quantifier instantiations).  In such a case, a lemma can
 495    * be asserted that is simplified away (perhaps it's already true).
 496    * However, we must maintain the invariant that, if a theory uses the
 497    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 498    * be performed before exit, even if no new facts are on its fact queue,
 499    * as it might decide to further instantiate some lemmas, precluding
 500    * a SAT response.
 501    */
 502   inline bool needCheck() const {
 503     return d_outputChannelUsed || d_lemmasAdded;
 504   }
 505   /**
 506    * Is the literal lit (possibly) critical for satisfying the input formula in
 507    * the current context? This call is applicable only during collectModelInfo
 508    * or during LAST_CALL effort.
 509    */
 510   bool isRelevant(Node lit) const;
 511
 512   /**
 513    * This is called at shutdown time by the SmtEngine, just before
 514    * destruction.  It is important because there are destruction
 515    * ordering issues between PropEngine and Theory.
 516    */
 517   void shutdown();
 518
 519   /**
 520    * Solve the given literal with a theory that owns it.
 521    */
 522   theory::Theory::PPAssertStatus solve(TNode literal,
 523                                     theory::SubstitutionMap& substitutionOut);
 524
 525   /**
 526    * Preregister a Theory atom with the responsible theory (or
 527    * theories).
 528    */
 529   void preRegister(TNode preprocessed);
 530
 531   /**
 532    * Assert the formula to the appropriate theory.
 533    * @param node the assertion
 534    */
 535   void assertFact(TNode node);
 536
 537   /**
 538    * Check all (currently-active) theories for conflicts.
 539    * @param effort the effort level to use
 540    */
 541   void check(theory::Theory::Effort effort);
 542
 543   /**
 544    * Run the combination framework.
 545    */
 546   void combineTheories();
 547
 548   /**
 549    * Calls ppStaticLearn() on all theories, accumulating their
 550    * combined contributions in the "learned" builder.
 551    */
 552   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 553
 554   /**
 555    * Calls presolve() on all theories and returns true
 556    * if one of the theories discovers a conflict.
 557    */
 558   bool presolve();
 559
 560    /**
 561    * Calls postsolve() on all theories.
 562    */
 563   void postsolve();
 564
 565   /**
 566    * Calls notifyRestart() on all active theories.
 567    */
 568   void notifyRestart();
 569
 570   void getPropagatedLiterals(std::vector<TNode>& literals) {
 571     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 572       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 573       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 574     }
 575   }
 576
 577   /**
 578    * Returns the next decision request, or null if none exist. The next
 579    * decision request is a literal that this theory engine prefers the SAT
 580    * solver to make as its next decision. Decision requests are managed by
 581    * the decision manager d_decManager.
 582    */
 583   Node getNextDecisionRequest();
 584
 585   bool properConflict(TNode conflict) const;
 586   bool properPropagation(TNode lit) const;
 587   bool properExplanation(TNode node, TNode expl) const;
 588
 589   /**
 590    * Returns an explanation of the node propagated to the SAT solver.
 591    */
 592   Node getExplanation(TNode node);
 593
 594   /**
 595    * Returns an explanation of the node propagated to the SAT solver and the theory
 596    * that propagated it.
 597    */
 598   Node getExplanationAndRecipe(TNode node, LemmaProofRecipe* proofRecipe);
 599
 600   /**
 601    * collect model info
 602    */
 603   bool collectModelInfo(theory::TheoryModel* m);
 604   /** post process model */
 605   void postProcessModel( theory::TheoryModel* m );
 606
 607   /**
 608    * Get the pointer to the model object used by this theory engine.
 609    */
 610   theory::TheoryModel* getModel();
 611   /**
 612    * Get the current model for the current set of assertions. This method
 613    * should only be called immediately after a satisfiable or unknown
 614    * response to a check-sat call, and only if produceModels is true.
 615    *
 616    * If the model is not already built, this will cause this theory engine
 617    * to build the model.
 618    *
 619    * If the model is not available (for instance, if the last call to check-sat
 620    * was interrupted), then this returns the null pointer.
 621    */
 622   theory::TheoryModel* getBuiltModel();
 623   /** set eager model building
 624    *
 625    * If this method is called, then this TheoryEngine will henceforth build
 626    * its model immediately after every satisfiability check that results
 627    * in a satisfiable or unknown result. The motivation for this mode is to
 628    * accomodate API users that get the model object from the TheoryEngine,
 629    * where we want to ensure that this model is always valid.
 630    * TODO (#2648): revisit this.
 631    */
 632   void setEagerModelBuilding() { d_eager_model_building = true; }
 633
 634   /** get synth solutions
 635    *
 636    * This method returns true if there is a synthesis solution available. This
 637    * is the case if the last call to check satisfiability originated in a
 638    * check-synth call, and the synthesis solver successfully found a solution
 639    * for all active synthesis conjectures.
 640    *
 641    * This method adds entries to sol_map that map functions-to-synthesize with
 642    * their solutions, for all active conjectures. This should be called
 643    * immediately after the solver answers unsat for sygus input.
 644    *
 645    * For details on what is added to sol_map, see
 646    * SynthConjecture::getSynthSolutions.
 647    */
 648   bool getSynthSolutions(std::map<Node, std::map<Node, Node> >& sol_map);
 649
 650   /**
 651    * Get the model builder
 652    */
 653   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 654
 655   /**
 656    * Get the theory associated to a given Node.
 657    *
 658    * @returns the theory, or NULL if the TNode is
 659    * of built-in type.
 660    */
 661   inline theory::Theory* theoryOf(TNode node) const {
 662     return d_theoryTable[theory::Theory::theoryOf(node)];
 663   }
 664
 665   /**
 666    * Get the theory associated to a the given theory id.
 667    *
 668    * @returns the theory
 669    */
 670   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 671     Assert(theoryId < theory::THEORY_LAST);
 672     return d_theoryTable[theoryId];
 673   }
 674
 675   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 676     return d_logicInfo.isTheoryEnabled(theoryId);
 677   }
 678   /** get the logic info used by this theory engine */
 679   const LogicInfo& getLogicInfo() const;
 680   /**
 681    * Returns the equality status of the two terms, from the theory
 682    * that owns the domain type.  The types of a and b must be the same.
 683    */
 684   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 685
 686   /**
 687    * Returns the value that a theory that owns the type of var currently
 688    * has (or null if none);
 689    */
 690   Node getModelValue(TNode var);
 691
 692   /**
 693    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 694    */
 695   Node ensureLiteral(TNode n);
 696
 697   /**
 698    * Print all instantiations made by the quantifiers module.
 699    */
 700   void printInstantiations( std::ostream& out );
 701
 702   /**
 703    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 704    */
 705   void printSynthSolution( std::ostream& out );
 706
 707   /**
 708    * Get list of quantified formulas that were instantiated
 709    */
 710   void getInstantiatedQuantifiedFormulas( std::vector< Node >& qs );
 711
 712   /**
 713    * Get instantiation methods
 714    *   first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
 715    *   second inputs forall x.q[x] and returns ( a, ..., z )
 716    *   third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] ) , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
 717    */
 718   void getInstantiations( Node q, std::vector< Node >& insts );
 719   void getInstantiationTermVectors( Node q, std::vector< std::vector< Node > >& tvecs );
 720   void getInstantiations( std::map< Node, std::vector< Node > >& insts );
 721   void getInstantiationTermVectors( std::map< Node, std::vector< std::vector< Node > > >& insts );
 722
 723   /**
 724    * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
 725    *   Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
 726    */
 727   Node getInstantiatedConjunction( Node q );
 728
 729   /**
 730    * Forwards an entailment check according to the given theoryOfMode.
 731    * See theory.h for documentation on entailmentCheck().
 732    */
 733   std::pair<bool, Node> entailmentCheck(options::TheoryOfMode mode, TNode lit);
 734
 735  private:
 736   /** Default visitor for pre-registration */
 737   PreRegisterVisitor d_preRegistrationVisitor;
 738
 739   /** Visitor for collecting shared terms */
 740   SharedTermsVisitor d_sharedTermsVisitor;
 741
 742   /** Dump the assertions to the dump */
 743   void dumpAssertions(const char* tag);
 744
 745   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 746 public:
 747
 748   SharedTermsDatabase* getSharedTermsDatabase();
 749
 750   SortInference* getSortInference() { return &d_sortInfer; }
 751
 752   /** Prints the assertions to the debug stream */
 753   void printAssertions(const char* tag);
 754
 755 private:
 756
 757   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 758
 759  public:
 760   /** Set user attribute.
 761    *
 762    * This function is called when an attribute is set by a user.  In SMT-LIBv2
 763    * this is done via the syntax (! n :attr)
 764    */
 765   void setUserAttribute(const std::string& attr,
 766                         Node n,
 767                         const std::vector<Node>& node_values,
 768                         const std::string& str_value);
 769
 770   /** Handle user attribute.
 771    *
 772    * Associates theory t with the attribute attr.  Theory t will be
 773    * notified whenever an attribute of name attr is set.
 774    */
 775   void handleUserAttribute(const char* attr, theory::Theory* t);
 776
 777   /**
 778    * Check that the theory assertions are satisfied in the model.
 779    * This function is called from the smt engine's checkModel routine.
 780    */
 781   void checkTheoryAssertionsWithModel(bool hardFailure);
 782
 783  private:
 784   IntStat d_arithSubstitutionsAdded;
 785
 786 };/* class TheoryEngine */
 787
 788 }/* CVC4 namespace */
 789
 790 #endif /* CVC4__THEORY_ENGINE_H */