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/decision_manager.h"
  39 #include "theory/engine_output_channel.h"
  40 #include "theory/interrupted.h"
  41 #include "theory/rewriter.h"
  42 #include "theory/shared_terms_database.h"
  43 #include "theory/sort_inference.h"
  44 #include "theory/substitutions.h"
  45 #include "theory/term_registration_visitor.h"
  46 #include "theory/theory.h"
  47 #include "theory/theory_preprocessor.h"
  48 #include "theory/uf/equality_engine.h"
  49 #include "theory/valuation.h"
  50 #include "util/hash.h"
  51 #include "util/resource_manager.h"
  52 #include "util/statistics_registry.h"
  53 #include "util/unsafe_interrupt_exception.h"
  54
  55 namespace CVC4 {
  56
  57 class ResourceManager;
  58 class LemmaProofRecipe;
  59
  60 /**
  61  * A pair of a theory and a node. This is used to mark the flow of
  62  * propagations between theories.
  63  */
  64 struct NodeTheoryPair {
  65   Node d_node;
  66   theory::TheoryId d_theory;
  67   size_t d_timestamp;
  68   NodeTheoryPair(TNode n, theory::TheoryId t, size_t ts = 0)
  69       : d_node(n), d_theory(t), d_timestamp(ts)
  70   {
  71   }
  72   NodeTheoryPair() : d_theory(theory::THEORY_LAST), d_timestamp() {}
  73   // Comparison doesn't take into account the timestamp
  74   bool operator == (const NodeTheoryPair& pair) const {
  75     return d_node == pair.d_node && d_theory == pair.d_theory;
  76   }
  77 };/* struct NodeTheoryPair */
  78
  79 struct NodeTheoryPairHashFunction {
  80   NodeHashFunction hashFunction;
  81   // Hash doesn't take into account the timestamp
  82   size_t operator()(const NodeTheoryPair& pair) const {
  83     uint64_t hash = fnv1a::fnv1a_64(NodeHashFunction()(pair.d_node));
  84     return static_cast<size_t>(fnv1a::fnv1a_64(pair.d_theory, hash));
  85   }
  86 };/* struct NodeTheoryPairHashFunction */
  87
  88
  89 /* Forward declarations */
  90 namespace theory {
  91   class TheoryModel;
  92   class TheoryEngineModelBuilder;
  93
  94   namespace eq {
  95     class EqualityEngine;
  96   }/* CVC4::theory::eq namespace */
  97
  98   namespace quantifiers {
  99     class TermDb;
 100   }
 101
 102   class EntailmentCheckParameters;
 103   class EntailmentCheckSideEffects;
 104 }/* CVC4::theory namespace */
 105
 106 class RemoveTermFormulas;
 107
 108 /**
 109  * This is essentially an abstraction for a collection of theories.  A
 110  * TheoryEngine provides services to a PropEngine, making various
 111  * T-solvers look like a single unit to the propositional part of
 112  * CVC4.
 113  */
 114 class TheoryEngine {
 115
 116   /** Shared terms database can use the internals notify the theories */
 117   friend class SharedTermsDatabase;
 118   friend class theory::quantifiers::TermDb;
 119   friend class theory::EngineOutputChannel;
 120
 121   /** Associated PropEngine engine */
 122   prop::PropEngine* d_propEngine;
 123
 124   /** Our context */
 125   context::Context* d_context;
 126
 127   /** Our user context */
 128   context::UserContext* d_userContext;
 129
 130   /**
 131    * A table of from theory IDs to theory pointers. Never use this table
 132    * directly, use theoryOf() instead.
 133    */
 134   theory::Theory* d_theoryTable[theory::THEORY_LAST];
 135
 136   /**
 137    * A collection of theories that are "active" for the current run.
 138    * This set is provided by the user (as a logic string, say, in SMT-LIBv2
 139    * format input), or else by default it's all-inclusive.  This is important
 140    * because we can optimize for single-theory runs (no sharing), can reduce
 141    * the cost of walking the DAG on registration, etc.
 142    */
 143   const LogicInfo& d_logicInfo;
 144
 145   /**
 146    * The database of shared terms.
 147    */
 148   SharedTermsDatabase d_sharedTerms;
 149
 150   /**
 151    * Master equality engine, to share with theories.
 152    */
 153   theory::eq::EqualityEngine* d_masterEqualityEngine;
 154
 155   /** notify class for master equality engine */
 156   class NotifyClass : public theory::eq::EqualityEngineNotify {
 157     TheoryEngine& d_te;
 158   public:
 159     NotifyClass(TheoryEngine& te): d_te(te) {}
 160     bool eqNotifyTriggerEquality(TNode equality, bool value) override
 161     {
 162       return true;
 163     }
 164     bool eqNotifyTriggerPredicate(TNode predicate, bool value) override
 165     {
 166       return true;
 167     }
 168     bool eqNotifyTriggerTermEquality(theory::TheoryId tag,
 169                                      TNode t1,
 170                                      TNode t2,
 171                                      bool value) override
 172     {
 173       return true;
 174     }
 175     void eqNotifyConstantTermMerge(TNode t1, TNode t2) override {}
 176     void eqNotifyNewClass(TNode t) override { d_te.eqNotifyNewClass(t); }
 177     void eqNotifyPreMerge(TNode t1, TNode t2) override
 178     {
 179     }
 180     void eqNotifyPostMerge(TNode t1, TNode t2) override
 181     {
 182     }
 183     void eqNotifyDisequal(TNode t1, TNode t2, TNode reason) override
 184     {
 185     }
 186   };/* class TheoryEngine::NotifyClass */
 187   NotifyClass d_masterEENotify;
 188
 189   /**
 190    * notification methods
 191    */
 192   void eqNotifyNewClass(TNode t);
 193   void eqNotifyPreMerge(TNode t1, TNode t2);
 194   void eqNotifyPostMerge(TNode t1, TNode t2);
 195   void eqNotifyDisequal(TNode t1, TNode t2, TNode reason);
 196
 197   /**
 198    * The quantifiers engine
 199    */
 200   theory::QuantifiersEngine* d_quantEngine;
 201   /**
 202    * The decision manager
 203    */
 204   std::unique_ptr<theory::DecisionManager> d_decManager;
 205
 206   /**
 207    * Default model object
 208    */
 209   theory::TheoryModel* d_curr_model;
 210   bool d_aloc_curr_model;
 211   /**
 212    * Model builder object
 213    */
 214   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 215   bool d_aloc_curr_model_builder;
 216   /** are we in eager model building mode? (see setEagerModelBuilding). */
 217   bool d_eager_model_building;
 218
 219   typedef std::unordered_map<Node, Node, NodeHashFunction> NodeMap;
 220   typedef std::unordered_map<TNode, Node, TNodeHashFunction> TNodeMap;
 221
 222   /**
 223    * Used for "missed-t-propagations" dumping mode only.  A set of all
 224    * theory-propagable literals.
 225    */
 226   context::CDList<TNode> d_possiblePropagations;
 227
 228   /**
 229    * Used for "missed-t-propagations" dumping mode only.  A
 230    * context-dependent set of those theory-propagable literals that
 231    * have been propagated.
 232    */
 233   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 234
 235   /**
 236    * Output channels for individual theories.
 237    */
 238   theory::EngineOutputChannel* d_theoryOut[theory::THEORY_LAST];
 239
 240   /**
 241    * Are we in conflict.
 242    */
 243   context::CDO<bool> d_inConflict;
 244
 245   /**
 246    * Are we in "SAT mode"? In this state, the user can query for the model.
 247    * This corresponds to the state in Figure 4.1, page 52 of the SMT-LIB
 248    * standard, version 2.6.
 249    */
 250   bool d_inSatMode;
 251
 252   /**
 253    * Called by the theories to notify of a conflict.
 254    */
 255   void conflict(TNode conflict, theory::TheoryId theoryId);
 256
 257   /**
 258    * Debugging flag to ensure that shutdown() is called before the
 259    * destructor.
 260    */
 261   bool d_hasShutDown;
 262
 263   /**
 264    * True if a theory has notified us of incompleteness (at this
 265    * context level or below).
 266    */
 267   context::CDO<bool> d_incomplete;
 268
 269   /**
 270    * Called by the theories to notify that the current branch is incomplete.
 271    */
 272   void setIncomplete(theory::TheoryId theory) {
 273     d_incomplete = true;
 274   }
 275
 276
 277   /**
 278    * Mapping of propagations from recievers to senders.
 279    */
 280   typedef context::CDHashMap<NodeTheoryPair, NodeTheoryPair, NodeTheoryPairHashFunction> PropagationMap;
 281   PropagationMap d_propagationMap;
 282
 283   /**
 284    * Timestamp of propagations
 285    */
 286   context::CDO<size_t> d_propagationMapTimestamp;
 287
 288   /**
 289    * Literals that are propagated by the theory. Note that these are TNodes.
 290    * The theory can only propagate nodes that have an assigned literal in the
 291    * SAT solver and are hence referenced in the SAT solver.
 292    */
 293   context::CDList<TNode> d_propagatedLiterals;
 294
 295   /**
 296    * The index of the next literal to be propagated by a theory.
 297    */
 298   context::CDO<unsigned> d_propagatedLiteralsIndex;
 299
 300   /**
 301    * Called by the output channel to propagate literals and facts
 302    * @return false if immediate conflict
 303    */
 304   bool propagate(TNode literal, theory::TheoryId theory);
 305
 306   /**
 307    * Internal method to call the propagation routines and collect the
 308    * propagated literals.
 309    */
 310   void propagate(theory::Theory::Effort effort);
 311
 312   /**
 313    * A variable to mark if we added any lemmas.
 314    */
 315   bool d_lemmasAdded;
 316
 317   /**
 318    * A variable to mark if the OutputChannel was "used" by any theory
 319    * since the start of the last check.  If it has been, we require
 320    * a FULL_EFFORT check before exiting and reporting SAT.
 321    *
 322    * See the documentation for the needCheck() function, below.
 323    */
 324   bool d_outputChannelUsed;
 325
 326   /** Atom requests from lemmas */
 327   AtomRequests d_atomRequests;
 328
 329   /**
 330    * Adds a new lemma, returning its status.
 331    * @param node the lemma
 332    * @param negated should the lemma be asserted negated
 333    * @param removable can the lemma be remove (restrictions apply)
 334    * @param needAtoms if not THEORY_LAST, then
 335    */
 336   theory::LemmaStatus lemma(TNode node,
 337                             ProofRule rule,
 338                             bool negated,
 339                             bool removable,
 340                             bool preprocess,
 341                             theory::TheoryId atomsTo);
 342
 343   /** Enusre that the given atoms are send to the given theory */
 344   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 345
 346   /** sort inference module */
 347   SortInference d_sortInfer;
 348
 349   /** The theory preprocessor */
 350   theory::TheoryPreprocessor d_tpp;
 351
 352   /** Time spent in theory combination */
 353   TimerStat d_combineTheoriesTime;
 354
 355   Node d_true;
 356   Node d_false;
 357
 358   /** Whether we were just interrupted (or not) */
 359   bool d_interrupted;
 360   ResourceManager* d_resourceManager;
 361
 362  public:
 363   /** Constructs a theory engine */
 364   TheoryEngine(context::Context* context,
 365                context::UserContext* userContext,
 366                RemoveTermFormulas& iteRemover,
 367                const LogicInfo& logic);
 368
 369   /** Destroys a theory engine */
 370   ~TheoryEngine();
 371
 372   void interrupt();
 373
 374   /** "Spend" a resource during a search or preprocessing.*/
 375   void spendResource(ResourceManager::Resource r);
 376
 377   /**
 378    * Adds a theory. Only one theory per TheoryId can be present, so if
 379    * there is another theory it will be deleted.
 380    */
 381   template <class TheoryClass>
 382   inline void addTheory(theory::TheoryId theoryId)
 383   {
 384     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 385     d_theoryOut[theoryId] = new theory::EngineOutputChannel(this, theoryId);
 386     d_theoryTable[theoryId] = new TheoryClass(d_context,
 387                                               d_userContext,
 388                                               *d_theoryOut[theoryId],
 389                                               theory::Valuation(this),
 390                                               d_logicInfo);
 391     theory::Rewriter::registerTheoryRewriter(
 392         theoryId, d_theoryTable[theoryId]->getTheoryRewriter());
 393   }
 394
 395   void setPropEngine(prop::PropEngine* propEngine)
 396   {
 397     d_propEngine = propEngine;
 398   }
 399
 400   /** Called when all initialization of options/logic is done */
 401   void finishInit();
 402
 403   /**
 404    * Get a pointer to the underlying propositional engine.
 405    */
 406   inline prop::PropEngine* getPropEngine() const {
 407     return d_propEngine;
 408   }
 409
 410   /**
 411    * Get a pointer to the underlying sat context.
 412    */
 413   inline context::Context* getSatContext() const {
 414     return d_context;
 415   }
 416
 417   /**
 418    * Get a pointer to the underlying user context.
 419    */
 420   inline context::Context* getUserContext() const {
 421     return d_userContext;
 422   }
 423
 424   /**
 425    * Get a pointer to the underlying quantifiers engine.
 426    */
 427   theory::QuantifiersEngine* getQuantifiersEngine() const {
 428     return d_quantEngine;
 429   }
 430   /**
 431    * Get a pointer to the underlying decision manager.
 432    */
 433   theory::DecisionManager* getDecisionManager() const
 434   {
 435     return d_decManager.get();
 436   }
 437
 438  private:
 439   /**
 440    * Queue of nodes for pre-registration.
 441    */
 442   std::queue<TNode> d_preregisterQueue;
 443
 444   /**
 445    * Boolean flag denoting we are in pre-registration.
 446    */
 447   bool d_inPreregister;
 448
 449   /**
 450    * Did the theories get any new facts since the last time we called
 451    * check()
 452    */
 453   context::CDO<bool> d_factsAsserted;
 454
 455   /**
 456    * Map from equality atoms to theories that would like to be notified about them.
 457    */
 458
 459
 460   /**
 461    * Assert the formula to the given theory.
 462    * @param assertion the assertion to send (not necesserily normalized)
 463    * @param original the assertion as it was sent in from the propagating theory
 464    * @param toTheoryId the theory to assert to
 465    * @param fromTheoryId the theory that sent it
 466    */
 467   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 468
 469   /**
 470    * Marks a theory propagation from a theory to a theory where a
 471    * theory could be the THEORY_SAT_SOLVER for literals coming from
 472    * or being propagated to the SAT solver. If the receiving theory
 473    * already recieved the literal, the method returns false, otherwise
 474    * it returns true.
 475    *
 476    * @param assertion the normalized assertion being sent
 477    * @param originalAssertion the actual assertion that was sent
 478    * @param toTheoryId the theory that is on the receiving end
 479    * @param fromTheoryId the theory that sent the assertion
 480    * @return true if a new assertion, false if theory already got it
 481    */
 482   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 483
 484   /**
 485    * Computes the explanation by travarsing the propagation graph and
 486    * asking relevant theories to explain the propagations. Initially
 487    * the explanation vector should contain only the element (node, theory)
 488    * where the node is the one to be explained, and the theory is the
 489    * theory that sent the literal. The lemmaProofRecipe will contain a list
 490    * of the explanation steps required to produce the original node.
 491    */
 492   void getExplanation(std::vector<NodeTheoryPair>& explanationVector, LemmaProofRecipe* lemmaProofRecipe);
 493
 494 public:
 495
 496   /**
 497    * Signal the start of a new round of assertion preprocessing
 498    */
 499   void preprocessStart();
 500
 501   /**
 502    * Runs theory specific preprocessing on the non-Boolean parts of
 503    * the formula.  This is only called on input assertions, after ITEs
 504    * have been removed.
 505    */
 506   Node preprocess(TNode node);
 507
 508   /** Notify (preprocessed) assertions. */
 509   void notifyPreprocessedAssertions(const std::vector<Node>& assertions);
 510
 511   /** Return whether or not we are incomplete (in the current context). */
 512   inline bool isIncomplete() const { return d_incomplete; }
 513
 514   /**
 515    * Returns true if we need another round of checking.  If this
 516    * returns true, check(FULL_EFFORT) _must_ be called by the
 517    * propositional layer before reporting SAT.
 518    *
 519    * This is especially necessary for incomplete theories that lazily
 520    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 521    * outputing quantifier instantiations).  In such a case, a lemma can
 522    * be asserted that is simplified away (perhaps it's already true).
 523    * However, we must maintain the invariant that, if a theory uses the
 524    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 525    * be performed before exit, even if no new facts are on its fact queue,
 526    * as it might decide to further instantiate some lemmas, precluding
 527    * a SAT response.
 528    */
 529   inline bool needCheck() const {
 530     return d_outputChannelUsed || d_lemmasAdded;
 531   }
 532
 533   /**
 534    * This is called at shutdown time by the SmtEngine, just before
 535    * destruction.  It is important because there are destruction
 536    * ordering issues between PropEngine and Theory.
 537    */
 538   void shutdown();
 539
 540   /**
 541    * Solve the given literal with a theory that owns it.
 542    */
 543   theory::Theory::PPAssertStatus solve(TNode literal,
 544                                     theory::SubstitutionMap& substitutionOut);
 545
 546   /**
 547    * Preregister a Theory atom with the responsible theory (or
 548    * theories).
 549    */
 550   void preRegister(TNode preprocessed);
 551
 552   /**
 553    * Assert the formula to the appropriate theory.
 554    * @param node the assertion
 555    */
 556   void assertFact(TNode node);
 557
 558   /**
 559    * Check all (currently-active) theories for conflicts.
 560    * @param effort the effort level to use
 561    */
 562   void check(theory::Theory::Effort effort);
 563
 564   /**
 565    * Run the combination framework.
 566    */
 567   void combineTheories();
 568
 569   /**
 570    * Calls ppStaticLearn() on all theories, accumulating their
 571    * combined contributions in the "learned" builder.
 572    */
 573   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 574
 575   /**
 576    * Calls presolve() on all theories and returns true
 577    * if one of the theories discovers a conflict.
 578    */
 579   bool presolve();
 580
 581    /**
 582    * Calls postsolve() on all theories.
 583    */
 584   void postsolve();
 585
 586   /**
 587    * Calls notifyRestart() on all active theories.
 588    */
 589   void notifyRestart();
 590
 591   void getPropagatedLiterals(std::vector<TNode>& literals) {
 592     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 593       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 594       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 595     }
 596   }
 597
 598   /**
 599    * Returns the next decision request, or null if none exist. The next
 600    * decision request is a literal that this theory engine prefers the SAT
 601    * solver to make as its next decision. Decision requests are managed by
 602    * the decision manager d_decManager.
 603    */
 604   Node getNextDecisionRequest();
 605
 606   bool properConflict(TNode conflict) const;
 607   bool properPropagation(TNode lit) const;
 608   bool properExplanation(TNode node, TNode expl) const;
 609
 610   /**
 611    * Returns an explanation of the node propagated to the SAT solver.
 612    */
 613   Node getExplanation(TNode node);
 614
 615   /**
 616    * Returns an explanation of the node propagated to the SAT solver and the theory
 617    * that propagated it.
 618    */
 619   Node getExplanationAndRecipe(TNode node, LemmaProofRecipe* proofRecipe);
 620
 621   /**
 622    * collect model info
 623    */
 624   bool collectModelInfo(theory::TheoryModel* m);
 625   /** post process model */
 626   void postProcessModel( theory::TheoryModel* m );
 627
 628   /**
 629    * Get the pointer to the model object used by this theory engine.
 630    */
 631   theory::TheoryModel* getModel();
 632   /**
 633    * Get the current model for the current set of assertions. This method
 634    * should only be called immediately after a satisfiable or unknown
 635    * response to a check-sat call, and only if produceModels is true.
 636    *
 637    * If the model is not already built, this will cause this theory engine
 638    * to build the model.
 639    *
 640    * If the model is not available (for instance, if the last call to check-sat
 641    * was interrupted), then this returns the null pointer.
 642    */
 643   theory::TheoryModel* getBuiltModel();
 644   /** set eager model building
 645    *
 646    * If this method is called, then this TheoryEngine will henceforth build
 647    * its model immediately after every satisfiability check that results
 648    * in a satisfiable or unknown result. The motivation for this mode is to
 649    * accomodate API users that get the model object from the TheoryEngine,
 650    * where we want to ensure that this model is always valid.
 651    * TODO (#2648): revisit this.
 652    */
 653   void setEagerModelBuilding() { d_eager_model_building = true; }
 654
 655   /** get synth solutions
 656    *
 657    * This method returns true if there is a synthesis solution available. This
 658    * is the case if the last call to check satisfiability originated in a
 659    * check-synth call, and the synthesis solver successfully found a solution
 660    * for all active synthesis conjectures.
 661    *
 662    * This method adds entries to sol_map that map functions-to-synthesize with
 663    * their solutions, for all active conjectures. This should be called
 664    * immediately after the solver answers unsat for sygus input.
 665    *
 666    * For details on what is added to sol_map, see
 667    * SynthConjecture::getSynthSolutions.
 668    */
 669   bool getSynthSolutions(std::map<Node, std::map<Node, Node> >& sol_map);
 670
 671   /**
 672    * Get the model builder
 673    */
 674   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 675
 676   /**
 677    * Get the theory associated to a given Node.
 678    *
 679    * @returns the theory, or NULL if the TNode is
 680    * of built-in type.
 681    */
 682   inline theory::Theory* theoryOf(TNode node) const {
 683     return d_theoryTable[theory::Theory::theoryOf(node)];
 684   }
 685
 686   /**
 687    * Get the theory associated to a the given theory id.
 688    *
 689    * @returns the theory
 690    */
 691   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 692     Assert(theoryId < theory::THEORY_LAST);
 693     return d_theoryTable[theoryId];
 694   }
 695
 696   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 697     return d_logicInfo.isTheoryEnabled(theoryId);
 698   }
 699   /** get the logic info used by this theory engine */
 700   const LogicInfo& getLogicInfo() const;
 701   /**
 702    * Returns the equality status of the two terms, from the theory
 703    * that owns the domain type.  The types of a and b must be the same.
 704    */
 705   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 706
 707   /**
 708    * Returns the value that a theory that owns the type of var currently
 709    * has (or null if none);
 710    */
 711   Node getModelValue(TNode var);
 712
 713   /**
 714    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 715    */
 716   Node ensureLiteral(TNode n);
 717
 718   /**
 719    * Print all instantiations made by the quantifiers module.
 720    */
 721   void printInstantiations( std::ostream& out );
 722
 723   /**
 724    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 725    */
 726   void printSynthSolution( std::ostream& out );
 727
 728   /**
 729    * Get list of quantified formulas that were instantiated
 730    */
 731   void getInstantiatedQuantifiedFormulas( std::vector< Node >& qs );
 732
 733   /**
 734    * Get instantiation methods
 735    *   first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
 736    *   second inputs forall x.q[x] and returns ( a, ..., z )
 737    *   third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] ) , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
 738    */
 739   void getInstantiations( Node q, std::vector< Node >& insts );
 740   void getInstantiationTermVectors( Node q, std::vector< std::vector< Node > >& tvecs );
 741   void getInstantiations( std::map< Node, std::vector< Node > >& insts );
 742   void getInstantiationTermVectors( std::map< Node, std::vector< std::vector< Node > > >& insts );
 743
 744   /**
 745    * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
 746    *   Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
 747    */
 748   Node getInstantiatedConjunction( Node q );
 749
 750   /**
 751    * Forwards an entailment check according to the given theoryOfMode.
 752    * See theory.h for documentation on entailmentCheck().
 753    */
 754   std::pair<bool, Node> entailmentCheck(
 755       options::TheoryOfMode mode,
 756       TNode lit,
 757       const theory::EntailmentCheckParameters* params = NULL,
 758       theory::EntailmentCheckSideEffects* out = NULL);
 759
 760  private:
 761   /** Default visitor for pre-registration */
 762   PreRegisterVisitor d_preRegistrationVisitor;
 763
 764   /** Visitor for collecting shared terms */
 765   SharedTermsVisitor d_sharedTermsVisitor;
 766
 767   /** Dump the assertions to the dump */
 768   void dumpAssertions(const char* tag);
 769
 770   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 771 public:
 772   void staticInitializeBVOptions(const std::vector<Node>& assertions);
 773
 774   Node ppSimpITE(TNode assertion);
 775   /** Returns false if an assertion simplified to false. */
 776   bool donePPSimpITE(std::vector<Node>& assertions);
 777
 778   SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; }
 779
 780   theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; }
 781
 782   SortInference* getSortInference() { return &d_sortInfer; }
 783
 784   /** Prints the assertions to the debug stream */
 785   void printAssertions(const char* tag);
 786
 787 private:
 788
 789   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 790
 791  public:
 792   /** Set user attribute.
 793    *
 794    * This function is called when an attribute is set by a user.  In SMT-LIBv2
 795    * this is done via the syntax (! n :attr)
 796    */
 797   void setUserAttribute(const std::string& attr,
 798                         Node n,
 799                         const std::vector<Node>& node_values,
 800                         const std::string& str_value);
 801
 802   /** Handle user attribute.
 803    *
 804    * Associates theory t with the attribute attr.  Theory t will be
 805    * notified whenever an attribute of name attr is set.
 806    */
 807   void handleUserAttribute(const char* attr, theory::Theory* t);
 808
 809   /**
 810    * Check that the theory assertions are satisfied in the model.
 811    * This function is called from the smt engine's checkModel routine.
 812    */
 813   void checkTheoryAssertionsWithModel(bool hardFailure);
 814
 815  private:
 816   IntStat d_arithSubstitutionsAdded;
 817
 818 };/* class TheoryEngine */
 819
 820 }/* CVC4 namespace */
 821
 822 #endif /* CVC4__THEORY_ENGINE_H */