src/theory/theory_engine.h

   1 /*********************                                                        */
   2 /*! \file theory_engine.h
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Dejan Jovanovic, Morgan Deters, Andrew Reynolds
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2018 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 <vector>
  27 #include <utility>
  28
  29 #include "base/cvc4_assert.h"
  30 #include "context/cdhashset.h"
  31 #include "expr/node.h"
  32 #include "options/options.h"
  33 #include "options/smt_options.h"
  34 #include "prop/prop_engine.h"
  35 #include "smt/command.h"
  36 #include "smt_util/lemma_channels.h"
  37 #include "theory/atom_requests.h"
  38 #include "theory/interrupted.h"
  39 #include "theory/rewriter.h"
  40 #include "theory/shared_terms_database.h"
  41 #include "theory/sort_inference.h"
  42 #include "theory/substitutions.h"
  43 #include "theory/term_registration_visitor.h"
  44 #include "theory/theory.h"
  45 #include "theory/uf/equality_engine.h"
  46 #include "theory/valuation.h"
  47 #include "util/hash.h"
  48 #include "util/statistics_registry.h"
  49 #include "util/unsafe_interrupt_exception.h"
  50
  51 namespace CVC4 {
  52
  53 class ResourceManager;
  54 class LemmaProofRecipe;
  55
  56 /**
  57  * A pair of a theory and a node. This is used to mark the flow of
  58  * propagations between theories.
  59  */
  60 struct NodeTheoryPair {
  61   Node node;
  62   theory::TheoryId theory;
  63   size_t timestamp;
  64   NodeTheoryPair(TNode node, theory::TheoryId theory, size_t timestamp = 0)
  65   : node(node), theory(theory), timestamp(timestamp) {}
  66   NodeTheoryPair() : theory(theory::THEORY_LAST), timestamp() {}
  67   // Comparison doesn't take into account the timestamp
  68   bool operator == (const NodeTheoryPair& pair) const {
  69     return node == pair.node && theory == pair.theory;
  70   }
  71 };/* struct NodeTheoryPair */
  72
  73 struct NodeTheoryPairHashFunction {
  74   NodeHashFunction hashFunction;
  75   // Hash doesn't take into account the timestamp
  76   size_t operator()(const NodeTheoryPair& pair) const {
  77     uint64_t hash = fnv1a::fnv1a_64(NodeHashFunction()(pair.node));
  78     return static_cast<size_t>(fnv1a::fnv1a_64(pair.theory, hash));
  79   }
  80 };/* struct NodeTheoryPairHashFunction */
  81
  82
  83 /* Forward declarations */
  84 namespace theory {
  85   class TheoryModel;
  86   class TheoryEngineModelBuilder;
  87   class ITEUtilities;
  88
  89   namespace eq {
  90     class EqualityEngine;
  91   }/* CVC4::theory::eq namespace */
  92
  93   namespace quantifiers {
  94     class TermDb;
  95   }
  96
  97   class EntailmentCheckParameters;
  98   class EntailmentCheckSideEffects;
  99 }/* CVC4::theory namespace */
 100
 101 class DecisionEngine;
 102 class RemoveTermFormulas;
 103 class UnconstrainedSimplifier;
 104
 105 /**
 106  * This is essentially an abstraction for a collection of theories.  A
 107  * TheoryEngine provides services to a PropEngine, making various
 108  * T-solvers look like a single unit to the propositional part of
 109  * CVC4.
 110  */
 111 class TheoryEngine {
 112
 113   /** Shared terms database can use the internals notify the theories */
 114   friend class SharedTermsDatabase;
 115   friend class theory::quantifiers::TermDb;
 116
 117   /** Associated PropEngine engine */
 118   prop::PropEngine* d_propEngine;
 119
 120   /** Access to decision engine */
 121   DecisionEngine* d_decisionEngine;
 122
 123   /** Our context */
 124   context::Context* d_context;
 125
 126   /** Our user context */
 127   context::UserContext* d_userContext;
 128
 129   /**
 130    * A table of from theory IDs to theory pointers. Never use this table
 131    * directly, use theoryOf() instead.
 132    */
 133   theory::Theory* d_theoryTable[theory::THEORY_LAST];
 134
 135   /**
 136    * A collection of theories that are "active" for the current run.
 137    * This set is provided by the user (as a logic string, say, in SMT-LIBv2
 138    * format input), or else by default it's all-inclusive.  This is important
 139    * because we can optimize for single-theory runs (no sharing), can reduce
 140    * the cost of walking the DAG on registration, etc.
 141    */
 142   const LogicInfo& d_logicInfo;
 143
 144   /**
 145    * The database of shared terms.
 146    */
 147   SharedTermsDatabase d_sharedTerms;
 148
 149   /**
 150    * Master equality engine, to share with theories.
 151    */
 152   theory::eq::EqualityEngine* d_masterEqualityEngine;
 153
 154   /** notify class for master equality engine */
 155   class NotifyClass : public theory::eq::EqualityEngineNotify {
 156     TheoryEngine& d_te;
 157   public:
 158     NotifyClass(TheoryEngine& te): d_te(te) {}
 159     bool eqNotifyTriggerEquality(TNode equality, bool value) override
 160     {
 161       return true;
 162     }
 163     bool eqNotifyTriggerPredicate(TNode predicate, bool value) override
 164     {
 165       return true;
 166     }
 167     bool eqNotifyTriggerTermEquality(theory::TheoryId tag,
 168                                      TNode t1,
 169                                      TNode t2,
 170                                      bool value) override
 171     {
 172       return true;
 173     }
 174     void eqNotifyConstantTermMerge(TNode t1, TNode t2) override {}
 175     void eqNotifyNewClass(TNode t) override { d_te.eqNotifyNewClass(t); }
 176     void eqNotifyPreMerge(TNode t1, TNode t2) override
 177     {
 178       d_te.eqNotifyPreMerge(t1, t2);
 179     }
 180     void eqNotifyPostMerge(TNode t1, TNode t2) override
 181     {
 182       d_te.eqNotifyPostMerge(t1, t2);
 183     }
 184     void eqNotifyDisequal(TNode t1, TNode t2, TNode reason) override
 185     {
 186       d_te.eqNotifyDisequal(t1, t2, reason);
 187     }
 188   };/* class TheoryEngine::NotifyClass */
 189   NotifyClass d_masterEENotify;
 190
 191   /**
 192    * notification methods
 193    */
 194   void eqNotifyNewClass(TNode t);
 195   void eqNotifyPreMerge(TNode t1, TNode t2);
 196   void eqNotifyPostMerge(TNode t1, TNode t2);
 197   void eqNotifyDisequal(TNode t1, TNode t2, TNode reason);
 198
 199   /**
 200    * The quantifiers engine
 201    */
 202   theory::QuantifiersEngine* d_quantEngine;
 203
 204   /**
 205    * Default model object
 206    */
 207   theory::TheoryModel* d_curr_model;
 208   bool d_aloc_curr_model;
 209   /**
 210    * Model builder object
 211    */
 212   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 213   bool d_aloc_curr_model_builder;
 214
 215   typedef std::unordered_map<Node, Node, NodeHashFunction> NodeMap;
 216   typedef std::unordered_map<TNode, Node, TNodeHashFunction> TNodeMap;
 217
 218   /**
 219   * Cache for theory-preprocessing of assertions
 220    */
 221   NodeMap d_ppCache;
 222
 223   /**
 224    * Used for "missed-t-propagations" dumping mode only.  A set of all
 225    * theory-propagable literals.
 226    */
 227   context::CDList<TNode> d_possiblePropagations;
 228
 229   /**
 230    * Used for "missed-t-propagations" dumping mode only.  A
 231    * context-dependent set of those theory-propagable literals that
 232    * have been propagated.
 233    */
 234   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 235
 236
 237   /**
 238    * Statistics for a particular theory.
 239    */
 240   class Statistics {
 241
 242     static std::string mkName(std::string prefix,
 243                               theory::TheoryId theory,
 244                               std::string suffix) {
 245       std::stringstream ss;
 246       ss << prefix << theory << suffix;
 247       return ss.str();
 248     }
 249
 250   public:
 251
 252     IntStat conflicts, propagations, lemmas, requirePhase, flipDecision, restartDemands;
 253
 254     Statistics(theory::TheoryId theory);
 255     ~Statistics();
 256   };/* class TheoryEngine::Statistics */
 257
 258   /**
 259    * An output channel for Theory that passes messages
 260    * back to a TheoryEngine.
 261    */
 262   class EngineOutputChannel : public theory::OutputChannel {
 263     friend class TheoryEngine;
 264
 265     /**
 266      * The theory engine we're communicating with.
 267      */
 268     TheoryEngine* d_engine;
 269
 270     /**
 271      * The statistics of the theory interractions.
 272      */
 273     Statistics d_statistics;
 274
 275     /** The theory owning this channel. */
 276     theory::TheoryId d_theory;
 277
 278    public:
 279     EngineOutputChannel(TheoryEngine* engine, theory::TheoryId theory)
 280         : d_engine(engine), d_statistics(theory), d_theory(theory) {}
 281
 282     void safePoint(uint64_t amount) override {
 283       spendResource(amount);
 284       if (d_engine->d_interrupted) {
 285         throw theory::Interrupted();
 286       }
 287     }
 288
 289     void conflict(TNode conflictNode,
 290                   std::unique_ptr<Proof> pf = nullptr) override;
 291     bool propagate(TNode literal) override;
 292
 293     theory::LemmaStatus lemma(TNode lemma, ProofRule rule,
 294                               bool removable = false, bool preprocess = false,
 295                               bool sendAtoms = false) override;
 296
 297     theory::LemmaStatus splitLemma(TNode lemma,
 298                                    bool removable = false) override;
 299
 300     void demandRestart() override {
 301       NodeManager* curr = NodeManager::currentNM();
 302       Node restartVar = curr->mkSkolem(
 303           "restartVar", curr->booleanType(),
 304           "A boolean variable asserted to be true to force a restart");
 305       Trace("theory::restart")
 306           << "EngineOutputChannel<" << d_theory << ">::restart(" << restartVar
 307           << ")" << std::endl;
 308       ++d_statistics.restartDemands;
 309       lemma(restartVar, RULE_INVALID, true);
 310     }
 311
 312     void requirePhase(TNode n, bool phase) override {
 313       Debug("theory") << "EngineOutputChannel::requirePhase(" << n << ", "
 314                       << phase << ")" << std::endl;
 315       ++d_statistics.requirePhase;
 316       d_engine->d_propEngine->requirePhase(n, phase);
 317     }
 318
 319     bool flipDecision() override {
 320       Debug("theory") << "EngineOutputChannel::flipDecision()" << std::endl;
 321       ++d_statistics.flipDecision;
 322       return d_engine->d_propEngine->flipDecision();
 323     }
 324
 325     void setIncomplete() override {
 326       Trace("theory") << "TheoryEngine::setIncomplete()" << std::endl;
 327       d_engine->setIncomplete(d_theory);
 328     }
 329
 330     void spendResource(unsigned amount) override {
 331       d_engine->spendResource(amount);
 332     }
 333
 334     void handleUserAttribute(const char* attr, theory::Theory* t) override {
 335       d_engine->handleUserAttribute(attr, t);
 336     }
 337
 338    private:
 339     /**
 340      * A helper function for registering lemma recipes with the proof engine
 341      */
 342     void registerLemmaRecipe(Node lemma, Node originalLemma, bool preprocess,
 343                              theory::TheoryId theoryId);
 344   }; /* class TheoryEngine::EngineOutputChannel */
 345
 346   /**
 347    * Output channels for individual theories.
 348    */
 349   EngineOutputChannel* d_theoryOut[theory::THEORY_LAST];
 350
 351   /**
 352    * Are we in conflict.
 353    */
 354   context::CDO<bool> d_inConflict;
 355
 356   /**
 357    * Called by the theories to notify of a conflict.
 358    */
 359   void conflict(TNode conflict, theory::TheoryId theoryId);
 360
 361   /**
 362    * Debugging flag to ensure that shutdown() is called before the
 363    * destructor.
 364    */
 365   bool d_hasShutDown;
 366
 367   /**
 368    * True if a theory has notified us of incompleteness (at this
 369    * context level or below).
 370    */
 371   context::CDO<bool> d_incomplete;
 372
 373   /**
 374    * Called by the theories to notify that the current branch is incomplete.
 375    */
 376   void setIncomplete(theory::TheoryId theory) {
 377     d_incomplete = true;
 378   }
 379
 380
 381   /**
 382    * Mapping of propagations from recievers to senders.
 383    */
 384   typedef context::CDHashMap<NodeTheoryPair, NodeTheoryPair, NodeTheoryPairHashFunction> PropagationMap;
 385   PropagationMap d_propagationMap;
 386
 387   /**
 388    * Timestamp of propagations
 389    */
 390   context::CDO<size_t> d_propagationMapTimestamp;
 391
 392   /**
 393    * Literals that are propagated by the theory. Note that these are TNodes.
 394    * The theory can only propagate nodes that have an assigned literal in the
 395    * SAT solver and are hence referenced in the SAT solver.
 396    */
 397   context::CDList<TNode> d_propagatedLiterals;
 398
 399   /**
 400    * The index of the next literal to be propagated by a theory.
 401    */
 402   context::CDO<unsigned> d_propagatedLiteralsIndex;
 403
 404   /**
 405    * Called by the output channel to propagate literals and facts
 406    * @return false if immediate conflict
 407    */
 408   bool propagate(TNode literal, theory::TheoryId theory);
 409
 410   /**
 411    * Internal method to call the propagation routines and collect the
 412    * propagated literals.
 413    */
 414   void propagate(theory::Theory::Effort effort);
 415
 416   /**
 417    * A variable to mark if we added any lemmas.
 418    */
 419   bool d_lemmasAdded;
 420
 421   /**
 422    * A variable to mark if the OutputChannel was "used" by any theory
 423    * since the start of the last check.  If it has been, we require
 424    * a FULL_EFFORT check before exiting and reporting SAT.
 425    *
 426    * See the documentation for the needCheck() function, below.
 427    */
 428   bool d_outputChannelUsed;
 429
 430   /** Atom requests from lemmas */
 431   AtomRequests d_atomRequests;
 432
 433   /**
 434    * Adds a new lemma, returning its status.
 435    * @param node the lemma
 436    * @param negated should the lemma be asserted negated
 437    * @param removable can the lemma be remove (restrictions apply)
 438    * @param needAtoms if not THEORY_LAST, then
 439    */
 440   theory::LemmaStatus lemma(TNode node,
 441                             ProofRule rule,
 442                             bool negated,
 443                             bool removable,
 444                             bool preprocess,
 445                             theory::TheoryId atomsTo);
 446
 447   /** Enusre that the given atoms are send to the given theory */
 448   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 449
 450   RemoveTermFormulas& d_tform_remover;
 451
 452   /** sort inference module */
 453   SortInference d_sortInfer;
 454
 455   /** Time spent in theory combination */
 456   TimerStat d_combineTheoriesTime;
 457
 458   Node d_true;
 459   Node d_false;
 460
 461   /** Whether we were just interrupted (or not) */
 462   bool d_interrupted;
 463   ResourceManager* d_resourceManager;
 464
 465   /** Container for lemma input and output channels. */
 466   LemmaChannels* d_channels;
 467
 468 public:
 469
 470   /** Constructs a theory engine */
 471   TheoryEngine(context::Context* context, context::UserContext* userContext,
 472                RemoveTermFormulas& iteRemover, const LogicInfo& logic,
 473                LemmaChannels* channels);
 474
 475   /** Destroys a theory engine */
 476   ~TheoryEngine();
 477
 478   void interrupt();
 479
 480   /** "Spend" a resource during a search or preprocessing.*/
 481   void spendResource(unsigned amount);
 482
 483   /**
 484    * Adds a theory. Only one theory per TheoryId can be present, so if
 485    * there is another theory it will be deleted.
 486    */
 487   template <class TheoryClass>
 488   inline void addTheory(theory::TheoryId theoryId) {
 489     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 490     d_theoryOut[theoryId] = new EngineOutputChannel(this, theoryId);
 491     d_theoryTable[theoryId] =
 492         new TheoryClass(d_context, d_userContext, *d_theoryOut[theoryId],
 493                         theory::Valuation(this), d_logicInfo);
 494   }
 495
 496   inline void setPropEngine(prop::PropEngine* propEngine) {
 497     Assert(d_propEngine == NULL);
 498     d_propEngine = propEngine;
 499   }
 500
 501   inline void setDecisionEngine(DecisionEngine* decisionEngine) {
 502     Assert(d_decisionEngine == NULL);
 503     d_decisionEngine = decisionEngine;
 504   }
 505
 506   /** Called when all initialization of options/logic is done */
 507   void finishInit();
 508
 509   /**
 510    * Get a pointer to the underlying propositional engine.
 511    */
 512   inline prop::PropEngine* getPropEngine() const {
 513     return d_propEngine;
 514   }
 515
 516   /**
 517    * Get a pointer to the underlying sat context.
 518    */
 519   inline context::Context* getSatContext() const {
 520     return d_context;
 521   }
 522
 523   /**
 524    * Get a pointer to the underlying user context.
 525    */
 526   inline context::Context* getUserContext() const {
 527     return d_userContext;
 528   }
 529
 530   /**
 531    * Get a pointer to the underlying quantifiers engine.
 532    */
 533   theory::QuantifiersEngine* getQuantifiersEngine() const {
 534     return d_quantEngine;
 535   }
 536
 537 private:
 538
 539   /**
 540    * Helper for preprocess
 541    */
 542   Node ppTheoryRewrite(TNode term);
 543
 544   /**
 545    * Queue of nodes for pre-registration.
 546    */
 547   std::queue<TNode> d_preregisterQueue;
 548
 549   /**
 550    * Boolean flag denoting we are in pre-registration.
 551    */
 552   bool d_inPreregister;
 553
 554   /**
 555    * Did the theories get any new facts since the last time we called
 556    * check()
 557    */
 558   context::CDO<bool> d_factsAsserted;
 559
 560   /**
 561    * Map from equality atoms to theories that would like to be notified about them.
 562    */
 563
 564
 565   /**
 566    * Assert the formula to the given theory.
 567    * @param assertion the assertion to send (not necesserily normalized)
 568    * @param original the assertion as it was sent in from the propagating theory
 569    * @param toTheoryId the theory to assert to
 570    * @param fromTheoryId the theory that sent it
 571    */
 572   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 573
 574   /**
 575    * Marks a theory propagation from a theory to a theory where a
 576    * theory could be the THEORY_SAT_SOLVER for literals coming from
 577    * or being propagated to the SAT solver. If the receiving theory
 578    * already recieved the literal, the method returns false, otherwise
 579    * it returns true.
 580    *
 581    * @param assertion the normalized assertion being sent
 582    * @param originalAssertion the actual assertion that was sent
 583    * @param toTheoryId the theory that is on the receiving end
 584    * @param fromTheoryId the theory that sent the assertino
 585    * @return true if a new assertion, false if theory already got it
 586    */
 587   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 588
 589   /**
 590    * Computes the explanation by travarsing the propagation graph and
 591    * asking relevant theories to explain the propagations. Initially
 592    * the explanation vector should contain only the element (node, theory)
 593    * where the node is the one to be explained, and the theory is the
 594    * theory that sent the literal. The lemmaProofRecipe will contain a list
 595    * of the explanation steps required to produce the original node.
 596    */
 597   void getExplanation(std::vector<NodeTheoryPair>& explanationVector, LemmaProofRecipe* lemmaProofRecipe);
 598
 599 public:
 600
 601   /**
 602    * Signal the start of a new round of assertion preprocessing
 603    */
 604   void preprocessStart();
 605
 606   /**
 607    * Runs theory specific preprocessing on the non-Boolean parts of
 608    * the formula.  This is only called on input assertions, after ITEs
 609    * have been removed.
 610    */
 611   Node preprocess(TNode node);
 612
 613   /** Notify (preprocessed) assertions. */
 614   void notifyPreprocessedAssertions(const std::vector<Node>& assertions);
 615
 616   /** Return whether or not we are incomplete (in the current context). */
 617   inline bool isIncomplete() const { return d_incomplete; }
 618
 619   /**
 620    * Returns true if we need another round of checking.  If this
 621    * returns true, check(FULL_EFFORT) _must_ be called by the
 622    * propositional layer before reporting SAT.
 623    *
 624    * This is especially necessary for incomplete theories that lazily
 625    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 626    * outputing quantifier instantiations).  In such a case, a lemma can
 627    * be asserted that is simplified away (perhaps it's already true).
 628    * However, we must maintain the invariant that, if a theory uses the
 629    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 630    * be performed before exit, even if no new facts are on its fact queue,
 631    * as it might decide to further instantiate some lemmas, precluding
 632    * a SAT response.
 633    */
 634   inline bool needCheck() const {
 635     return d_outputChannelUsed || d_lemmasAdded;
 636   }
 637
 638   /**
 639    * This is called at shutdown time by the SmtEngine, just before
 640    * destruction.  It is important because there are destruction
 641    * ordering issues between PropEngine and Theory.
 642    */
 643   void shutdown();
 644
 645   /**
 646    * Solve the given literal with a theory that owns it.
 647    */
 648   theory::Theory::PPAssertStatus solve(TNode literal,
 649                                     theory::SubstitutionMap& substitutionOut);
 650
 651   /**
 652    * Preregister a Theory atom with the responsible theory (or
 653    * theories).
 654    */
 655   void preRegister(TNode preprocessed);
 656
 657   /**
 658    * Assert the formula to the appropriate theory.
 659    * @param node the assertion
 660    */
 661   void assertFact(TNode node);
 662
 663   /**
 664    * Check all (currently-active) theories for conflicts.
 665    * @param effort the effort level to use
 666    */
 667   void check(theory::Theory::Effort effort);
 668
 669   /**
 670    * Run the combination framework.
 671    */
 672   void combineTheories();
 673
 674   /**
 675    * Calls ppStaticLearn() on all theories, accumulating their
 676    * combined contributions in the "learned" builder.
 677    */
 678   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 679
 680   /**
 681    * Calls presolve() on all theories and returns true
 682    * if one of the theories discovers a conflict.
 683    */
 684   bool presolve();
 685
 686    /**
 687    * Calls postsolve() on all theories.
 688    */
 689   void postsolve();
 690
 691   /**
 692    * Calls notifyRestart() on all active theories.
 693    */
 694   void notifyRestart();
 695
 696   void getPropagatedLiterals(std::vector<TNode>& literals) {
 697     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 698       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 699       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 700     }
 701   }
 702
 703   Node getNextDecisionRequest();
 704
 705   bool properConflict(TNode conflict) const;
 706   bool properPropagation(TNode lit) const;
 707   bool properExplanation(TNode node, TNode expl) const;
 708
 709   /**
 710    * Returns an explanation of the node propagated to the SAT solver.
 711    */
 712   Node getExplanation(TNode node);
 713
 714   /**
 715    * Returns an explanation of the node propagated to the SAT solver and the theory
 716    * that propagated it.
 717    */
 718   Node getExplanationAndRecipe(TNode node, LemmaProofRecipe* proofRecipe);
 719
 720   /**
 721    * collect model info
 722    */
 723   bool collectModelInfo(theory::TheoryModel* m);
 724   /** post process model */
 725   void postProcessModel( theory::TheoryModel* m );
 726
 727   /**
 728    * Get the current model
 729    */
 730   theory::TheoryModel* getModel();
 731
 732   /** get synth solutions
 733    *
 734    * This function adds entries to sol_map that map functions-to-synthesize with
 735    * their solutions, for all active conjectures. This should be called
 736    * immediately after the solver answers unsat for sygus input.
 737    *
 738    * For details on what is added to sol_map, see
 739    * CegConjecture::getSynthSolutions.
 740    */
 741   void getSynthSolutions(std::map<Node, Node>& sol_map);
 742
 743   /**
 744    * Get the model builder
 745    */
 746   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 747
 748   /**
 749    * Get the theory associated to a given Node.
 750    *
 751    * @returns the theory, or NULL if the TNode is
 752    * of built-in type.
 753    */
 754   inline theory::Theory* theoryOf(TNode node) const {
 755     return d_theoryTable[theory::Theory::theoryOf(node)];
 756   }
 757
 758   /**
 759    * Get the theory associated to a the given theory id.
 760    *
 761    * @returns the theory
 762    */
 763   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 764     return d_theoryTable[theoryId];
 765   }
 766
 767   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 768     return d_logicInfo.isTheoryEnabled(theoryId);
 769   }
 770   /** get the logic info used by this theory engine */
 771   const LogicInfo& getLogicInfo() const;
 772   /**
 773    * Returns the equality status of the two terms, from the theory
 774    * that owns the domain type.  The types of a and b must be the same.
 775    */
 776   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 777
 778   /**
 779    * Returns the value that a theory that owns the type of var currently
 780    * has (or null if none);
 781    */
 782   Node getModelValue(TNode var);
 783
 784   /**
 785    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 786    */
 787   Node ensureLiteral(TNode n);
 788
 789   /**
 790    * Print all instantiations made by the quantifiers module.
 791    */
 792   void printInstantiations( std::ostream& out );
 793
 794   /**
 795    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 796    */
 797   void printSynthSolution( std::ostream& out );
 798
 799   /**
 800    * Get list of quantified formulas that were instantiated
 801    */
 802   void getInstantiatedQuantifiedFormulas( std::vector< Node >& qs );
 803
 804   /**
 805    * Get instantiation methods
 806    *   first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
 807    *   second inputs forall x.q[x] and returns ( a, ..., z )
 808    *   third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] ) , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
 809    */
 810   void getInstantiations( Node q, std::vector< Node >& insts );
 811   void getInstantiationTermVectors( Node q, std::vector< std::vector< Node > >& tvecs );
 812   void getInstantiations( std::map< Node, std::vector< Node > >& insts );
 813   void getInstantiationTermVectors( std::map< Node, std::vector< std::vector< Node > > >& insts );
 814
 815   /**
 816    * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
 817    *   Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
 818    */
 819   Node getInstantiatedConjunction( Node q );
 820
 821   /**
 822    * Forwards an entailment check according to the given theoryOfMode.
 823    * See theory.h for documentation on entailmentCheck().
 824    */
 825   std::pair<bool, Node> entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL);
 826
 827 private:
 828
 829   /** Default visitor for pre-registration */
 830   PreRegisterVisitor d_preRegistrationVisitor;
 831
 832   /** Visitor for collecting shared terms */
 833   SharedTermsVisitor d_sharedTermsVisitor;
 834
 835   /** Dump the assertions to the dump */
 836   void dumpAssertions(const char* tag);
 837
 838   /**
 839    * A collection of ite preprocessing passes.
 840    */
 841   theory::ITEUtilities* d_iteUtilities;
 842
 843
 844   /** For preprocessing pass simplifying unconstrained expressions */
 845   UnconstrainedSimplifier* d_unconstrainedSimp;
 846
 847   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 848 public:
 849   void staticInitializeBVOptions(const std::vector<Node>& assertions);
 850
 851   Node ppSimpITE(TNode assertion);
 852   /** Returns false if an assertion simplified to false. */
 853   bool donePPSimpITE(std::vector<Node>& assertions);
 854
 855   void ppUnconstrainedSimp(std::vector<Node>& assertions);
 856
 857   SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; }
 858
 859   theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; }
 860
 861   RemoveTermFormulas* getTermFormulaRemover() { return &d_tform_remover; }
 862
 863   SortInference* getSortInference() { return &d_sortInfer; }
 864
 865   /** Prints the assertions to the debug stream */
 866   void printAssertions(const char* tag);
 867
 868   /** Theory alternative is in use. */
 869   bool useTheoryAlternative(const std::string& name);
 870
 871   /** Enables using a theory alternative by name. */
 872   void enableTheoryAlternative(const std::string& name);
 873
 874 private:
 875   std::set< std::string > d_theoryAlternatives;
 876
 877   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 878
 879  public:
 880   /** Set user attribute.
 881    *
 882    * This function is called when an attribute is set by a user.  In SMT-LIBv2
 883    * this is done via the syntax (! n :attr)
 884    */
 885   void setUserAttribute(const std::string& attr,
 886                         Node n,
 887                         const std::vector<Node>& node_values,
 888                         const std::string& str_value);
 889
 890   /** Handle user attribute.
 891    *
 892    * Associates theory t with the attribute attr.  Theory t will be
 893    * notified whenever an attribute of name attr is set.
 894    */
 895   void handleUserAttribute(const char* attr, theory::Theory* t);
 896
 897   /**
 898    * Check that the theory assertions are satisfied in the model.
 899    * This function is called from the smt engine's checkModel routine.
 900    */
 901   void checkTheoryAssertionsWithModel(bool hardFailure);
 902
 903  private:
 904   IntStat d_arithSubstitutionsAdded;
 905
 906 };/* class TheoryEngine */
 907
 908 }/* CVC4 namespace */
 909
 910 #endif /* __CVC4__THEORY_ENGINE_H */