src/theory/theory_engine.h

   1 /*********************                                                        */
   2 /*! \file theory_engine.h
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Morgan Deters, Dejan Jovanovic, Andrew Reynolds
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2017 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 <set>
  24 #include <unordered_map>
  25 #include <vector>
  26 #include <utility>
  27
  28 #include "base/cvc4_assert.h"
  29 #include "context/cdhashset.h"
  30 #include "expr/node.h"
  31 #include "options/options.h"
  32 #include "options/smt_options.h"
  33 #include "prop/prop_engine.h"
  34 #include "smt/command.h"
  35 #include "smt_util/lemma_channels.h"
  36 #include "theory/atom_requests.h"
  37 #include "theory/bv/bv_to_bool.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()
  67   : theory(theory::THEORY_LAST) {}
  68   // Comparison doesn't take into account the timestamp
  69   bool operator == (const NodeTheoryPair& pair) const {
  70     return node == pair.node && theory == pair.theory;
  71   }
  72 };/* struct NodeTheoryPair */
  73
  74 struct NodeTheoryPairHashFunction {
  75   NodeHashFunction hashFunction;
  76   // Hash doesn't take into account the timestamp
  77   size_t operator()(const NodeTheoryPair& pair) const {
  78     uint64_t hash = fnv1a::fnv1a_64(NodeHashFunction()(pair.node));
  79     return static_cast<size_t>(fnv1a::fnv1a_64(pair.theory, hash));
  80   }
  81 };/* struct NodeTheoryPairHashFunction */
  82
  83
  84 /* Forward declarations */
  85 namespace theory {
  86   class TheoryModel;
  87   class TheoryEngineModelBuilder;
  88   class ITEUtilities;
  89
  90   namespace eq {
  91     class EqualityEngine;
  92   }/* CVC4::theory::eq namespace */
  93
  94   namespace quantifiers {
  95     class TermDb;
  96   }
  97
  98   class EntailmentCheckParameters;
  99   class EntailmentCheckSideEffects;
 100 }/* CVC4::theory namespace */
 101
 102 class DecisionEngine;
 103 class RemoveTermFormulas;
 104 class UnconstrainedSimplifier;
 105
 106 /**
 107  * This is essentially an abstraction for a collection of theories.  A
 108  * TheoryEngine provides services to a PropEngine, making various
 109  * T-solvers look like a single unit to the propositional part of
 110  * CVC4.
 111  */
 112 class TheoryEngine {
 113
 114   /** Shared terms database can use the internals notify the theories */
 115   friend class SharedTermsDatabase;
 116   friend class theory::quantifiers::TermDb;
 117
 118   /** Associated PropEngine engine */
 119   prop::PropEngine* d_propEngine;
 120
 121   /** Access to decision engine */
 122   DecisionEngine* d_decisionEngine;
 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) { return true; }
 161     bool eqNotifyTriggerPredicate(TNode predicate, bool value) { return true; }
 162     bool eqNotifyTriggerTermEquality(theory::TheoryId tag, TNode t1, TNode t2, bool value) { return true; }
 163     void eqNotifyConstantTermMerge(TNode t1, TNode t2) {}
 164     void eqNotifyNewClass(TNode t) { d_te.eqNotifyNewClass(t); }
 165     void eqNotifyPreMerge(TNode t1, TNode t2) { d_te.eqNotifyPreMerge(t1, t2); }
 166     void eqNotifyPostMerge(TNode t1, TNode t2) { d_te.eqNotifyPostMerge(t1, t2); }
 167     void eqNotifyDisequal(TNode t1, TNode t2, TNode reason) { d_te.eqNotifyDisequal(t1, t2, reason); }
 168   };/* class TheoryEngine::NotifyClass */
 169   NotifyClass d_masterEENotify;
 170
 171   /**
 172    * notification methods
 173    */
 174   void eqNotifyNewClass(TNode t);
 175   void eqNotifyPreMerge(TNode t1, TNode t2);
 176   void eqNotifyPostMerge(TNode t1, TNode t2);
 177   void eqNotifyDisequal(TNode t1, TNode t2, TNode reason);
 178
 179   /**
 180    * The quantifiers engine
 181    */
 182   theory::QuantifiersEngine* d_quantEngine;
 183
 184   /**
 185    * Default model object
 186    */
 187   theory::TheoryModel* d_curr_model;
 188   bool d_aloc_curr_model;
 189   /**
 190    * Model builder object
 191    */
 192   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 193   bool d_aloc_curr_model_builder;
 194
 195   typedef std::unordered_map<Node, Node, NodeHashFunction> NodeMap;
 196   typedef std::unordered_map<TNode, Node, TNodeHashFunction> TNodeMap;
 197
 198   /**
 199   * Cache for theory-preprocessing of assertions
 200    */
 201   NodeMap d_ppCache;
 202
 203   /**
 204    * Used for "missed-t-propagations" dumping mode only.  A set of all
 205    * theory-propagable literals.
 206    */
 207   context::CDList<TNode> d_possiblePropagations;
 208
 209   /**
 210    * Used for "missed-t-propagations" dumping mode only.  A
 211    * context-dependent set of those theory-propagable literals that
 212    * have been propagated.
 213    */
 214   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 215
 216
 217   /**
 218    * Statistics for a particular theory.
 219    */
 220   class Statistics {
 221
 222     static std::string mkName(std::string prefix,
 223                               theory::TheoryId theory,
 224                               std::string suffix) {
 225       std::stringstream ss;
 226       ss << prefix << theory << suffix;
 227       return ss.str();
 228     }
 229
 230   public:
 231
 232     IntStat conflicts, propagations, lemmas, requirePhase, flipDecision, restartDemands;
 233
 234     Statistics(theory::TheoryId theory);
 235     ~Statistics();
 236   };/* class TheoryEngine::Statistics */
 237
 238   /**
 239    * An output channel for Theory that passes messages
 240    * back to a TheoryEngine.
 241    */
 242   class EngineOutputChannel : public theory::OutputChannel {
 243     friend class TheoryEngine;
 244
 245     /**
 246      * The theory engine we're communicating with.
 247      */
 248     TheoryEngine* d_engine;
 249
 250     /**
 251      * The statistics of the theory interractions.
 252      */
 253     Statistics d_statistics;
 254
 255     /** The theory owning this channel. */
 256     theory::TheoryId d_theory;
 257
 258    public:
 259     EngineOutputChannel(TheoryEngine* engine, theory::TheoryId theory)
 260         : d_engine(engine), d_statistics(theory), d_theory(theory) {}
 261
 262     void safePoint(uint64_t amount) override {
 263       spendResource(amount);
 264       if (d_engine->d_interrupted) {
 265         throw theory::Interrupted();
 266       }
 267     }
 268
 269     void conflict(TNode conflictNode, Proof* pf = nullptr) override;
 270     bool propagate(TNode literal) override;
 271
 272     theory::LemmaStatus lemma(TNode lemma, ProofRule rule,
 273                               bool removable = false, bool preprocess = false,
 274                               bool sendAtoms = false) override;
 275
 276     theory::LemmaStatus splitLemma(TNode lemma,
 277                                    bool removable = false) override;
 278
 279     void demandRestart() override {
 280       NodeManager* curr = NodeManager::currentNM();
 281       Node restartVar = curr->mkSkolem(
 282           "restartVar", curr->booleanType(),
 283           "A boolean variable asserted to be true to force a restart");
 284       Trace("theory::restart")
 285           << "EngineOutputChannel<" << d_theory << ">::restart(" << restartVar
 286           << ")" << std::endl;
 287       ++d_statistics.restartDemands;
 288       lemma(restartVar, RULE_INVALID, true);
 289     }
 290
 291     void requirePhase(TNode n, bool phase) override {
 292       Debug("theory") << "EngineOutputChannel::requirePhase(" << n << ", "
 293                       << phase << ")" << std::endl;
 294       ++d_statistics.requirePhase;
 295       d_engine->d_propEngine->requirePhase(n, phase);
 296     }
 297
 298     bool flipDecision() override {
 299       Debug("theory") << "EngineOutputChannel::flipDecision()" << std::endl;
 300       ++d_statistics.flipDecision;
 301       return d_engine->d_propEngine->flipDecision();
 302     }
 303
 304     void setIncomplete() override {
 305       Trace("theory") << "TheoryEngine::setIncomplete()" << std::endl;
 306       d_engine->setIncomplete(d_theory);
 307     }
 308
 309     void spendResource(unsigned amount) override {
 310       d_engine->spendResource(amount);
 311     }
 312
 313     void handleUserAttribute(const char* attr, theory::Theory* t) override {
 314       d_engine->handleUserAttribute(attr, t);
 315     }
 316
 317    private:
 318     /**
 319      * A helper function for registering lemma recipes with the proof engine
 320      */
 321     void registerLemmaRecipe(Node lemma, Node originalLemma, bool preprocess,
 322                              theory::TheoryId theoryId);
 323   }; /* class TheoryEngine::EngineOutputChannel */
 324
 325   /**
 326    * Output channels for individual theories.
 327    */
 328   EngineOutputChannel* d_theoryOut[theory::THEORY_LAST];
 329
 330   /**
 331    * Are we in conflict.
 332    */
 333   context::CDO<bool> d_inConflict;
 334
 335   /**
 336    * Called by the theories to notify of a conflict.
 337    */
 338   void conflict(TNode conflict, theory::TheoryId theoryId);
 339
 340   /**
 341    * Debugging flag to ensure that shutdown() is called before the
 342    * destructor.
 343    */
 344   bool d_hasShutDown;
 345
 346   /**
 347    * True if a theory has notified us of incompleteness (at this
 348    * context level or below).
 349    */
 350   context::CDO<bool> d_incomplete;
 351
 352   /**
 353    * Called by the theories to notify that the current branch is incomplete.
 354    */
 355   void setIncomplete(theory::TheoryId theory) {
 356     d_incomplete = true;
 357   }
 358
 359
 360   /**
 361    * Mapping of propagations from recievers to senders.
 362    */
 363   typedef context::CDHashMap<NodeTheoryPair, NodeTheoryPair, NodeTheoryPairHashFunction> PropagationMap;
 364   PropagationMap d_propagationMap;
 365
 366   /**
 367    * Timestamp of propagations
 368    */
 369   context::CDO<size_t> d_propagationMapTimestamp;
 370
 371   /**
 372    * Literals that are propagated by the theory. Note that these are TNodes.
 373    * The theory can only propagate nodes that have an assigned literal in the
 374    * SAT solver and are hence referenced in the SAT solver.
 375    */
 376   context::CDList<TNode> d_propagatedLiterals;
 377
 378   /**
 379    * The index of the next literal to be propagated by a theory.
 380    */
 381   context::CDO<unsigned> d_propagatedLiteralsIndex;
 382
 383   /**
 384    * Called by the output channel to propagate literals and facts
 385    * @return false if immediate conflict
 386    */
 387   bool propagate(TNode literal, theory::TheoryId theory);
 388
 389   /**
 390    * Internal method to call the propagation routines and collect the
 391    * propagated literals.
 392    */
 393   void propagate(theory::Theory::Effort effort);
 394
 395   /**
 396    * Called by the output channel to request decisions "as soon as
 397    * possible."
 398    */
 399   void propagateAsDecision(TNode literal, theory::TheoryId theory);
 400
 401   /**
 402    * A variable to mark if we added any lemmas.
 403    */
 404   bool d_lemmasAdded;
 405
 406   /**
 407    * A variable to mark if the OutputChannel was "used" by any theory
 408    * since the start of the last check.  If it has been, we require
 409    * a FULL_EFFORT check before exiting and reporting SAT.
 410    *
 411    * See the documentation for the needCheck() function, below.
 412    */
 413   bool d_outputChannelUsed;
 414
 415   /** Atom requests from lemmas */
 416   AtomRequests d_atomRequests;
 417
 418   /**
 419    * Adds a new lemma, returning its status.
 420    * @param node the lemma
 421    * @param negated should the lemma be asserted negated
 422    * @param removable can the lemma be remove (restrictions apply)
 423    * @param needAtoms if not THEORY_LAST, then
 424    */
 425   theory::LemmaStatus lemma(TNode node,
 426                             ProofRule rule,
 427                             bool negated,
 428                             bool removable,
 429                             bool preprocess,
 430                             theory::TheoryId atomsTo);
 431
 432   /** Enusre that the given atoms are send to the given theory */
 433   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 434
 435   RemoveTermFormulas& d_tform_remover;
 436
 437   /** sort inference module */
 438   SortInference d_sortInfer;
 439
 440   /** Time spent in theory combination */
 441   TimerStat d_combineTheoriesTime;
 442
 443   Node d_true;
 444   Node d_false;
 445
 446   /** Whether we were just interrupted (or not) */
 447   bool d_interrupted;
 448   ResourceManager* d_resourceManager;
 449
 450   /** Container for lemma input and output channels. */
 451   LemmaChannels* d_channels;
 452
 453 public:
 454
 455   /** Constructs a theory engine */
 456   TheoryEngine(context::Context* context, context::UserContext* userContext,
 457                RemoveTermFormulas& iteRemover, const LogicInfo& logic,
 458                LemmaChannels* channels);
 459
 460   /** Destroys a theory engine */
 461   ~TheoryEngine();
 462
 463   void interrupt() throw(ModalException);
 464   /**
 465    * "Spend" a resource during a search or preprocessing.
 466    */
 467   void spendResource(unsigned amount);
 468
 469   /**
 470    * Adds a theory. Only one theory per TheoryId can be present, so if
 471    * there is another theory it will be deleted.
 472    */
 473   template <class TheoryClass>
 474   inline void addTheory(theory::TheoryId theoryId) {
 475     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 476     d_theoryOut[theoryId] = new EngineOutputChannel(this, theoryId);
 477     d_theoryTable[theoryId] =
 478         new TheoryClass(d_context, d_userContext, *d_theoryOut[theoryId],
 479                         theory::Valuation(this), d_logicInfo);
 480   }
 481
 482   inline void setPropEngine(prop::PropEngine* propEngine) {
 483     Assert(d_propEngine == NULL);
 484     d_propEngine = propEngine;
 485   }
 486
 487   inline void setDecisionEngine(DecisionEngine* decisionEngine) {
 488     Assert(d_decisionEngine == NULL);
 489     d_decisionEngine = decisionEngine;
 490   }
 491
 492   /** Called when all initialization of options/logic is done */
 493   void finishInit();
 494
 495   /**
 496    * Get a pointer to the underlying propositional engine.
 497    */
 498   inline prop::PropEngine* getPropEngine() const {
 499     return d_propEngine;
 500   }
 501
 502   /**
 503    * Get a pointer to the underlying sat context.
 504    */
 505   inline context::Context* getSatContext() const {
 506     return d_context;
 507   }
 508
 509   /**
 510    * Get a pointer to the underlying user context.
 511    */
 512   inline context::Context* getUserContext() const {
 513     return d_userContext;
 514   }
 515
 516   /**
 517    * Get a pointer to the underlying quantifiers engine.
 518    */
 519   theory::QuantifiersEngine* getQuantifiersEngine() const {
 520     return d_quantEngine;
 521   }
 522
 523 private:
 524
 525   /**
 526    * Helper for preprocess
 527    */
 528   Node ppTheoryRewrite(TNode term);
 529
 530   /**
 531    * Queue of nodes for pre-registration.
 532    */
 533   std::queue<TNode> d_preregisterQueue;
 534
 535   /**
 536    * Boolean flag denoting we are in pre-registration.
 537    */
 538   bool d_inPreregister;
 539
 540   /**
 541    * Did the theories get any new facts since the last time we called
 542    * check()
 543    */
 544   context::CDO<bool> d_factsAsserted;
 545
 546   /**
 547    * Map from equality atoms to theories that would like to be notified about them.
 548    */
 549
 550
 551   /**
 552    * Assert the formula to the given theory.
 553    * @param assertion the assertion to send (not necesserily normalized)
 554    * @param original the assertion as it was sent in from the propagating theory
 555    * @param toTheoryId the theory to assert to
 556    * @param fromTheoryId the theory that sent it
 557    */
 558   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 559
 560   /**
 561    * Marks a theory propagation from a theory to a theory where a
 562    * theory could be the THEORY_SAT_SOLVER for literals coming from
 563    * or being propagated to the SAT solver. If the receiving theory
 564    * already recieved the literal, the method returns false, otherwise
 565    * it returns true.
 566    *
 567    * @param assertion the normalized assertion being sent
 568    * @param originalAssertion the actual assertion that was sent
 569    * @param toTheoryId the theory that is on the receiving end
 570    * @param fromTheoryId the theory that sent the assertino
 571    * @return true if a new assertion, false if theory already got it
 572    */
 573   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 574
 575   /**
 576    * Computes the explanation by travarsing the propagation graph and
 577    * asking relevant theories to explain the propagations. Initially
 578    * the explanation vector should contain only the element (node, theory)
 579    * where the node is the one to be explained, and the theory is the
 580    * theory that sent the literal. The lemmaProofRecipe will contain a list
 581    * of the explanation steps required to produce the original node.
 582    */
 583   void getExplanation(std::vector<NodeTheoryPair>& explanationVector, LemmaProofRecipe* lemmaProofRecipe);
 584
 585 public:
 586
 587   /**
 588    * Signal the start of a new round of assertion preprocessing
 589    */
 590   void preprocessStart();
 591
 592   /**
 593    * Runs theory specific preprocessing on the non-Boolean parts of
 594    * the formula.  This is only called on input assertions, after ITEs
 595    * have been removed.
 596    */
 597   Node preprocess(TNode node);
 598
 599   /** Notify (preprocessed) assertions. */
 600   void notifyPreprocessedAssertions(const std::vector<Node>& assertions);
 601
 602   /** Return whether or not we are incomplete (in the current context). */
 603   inline bool isIncomplete() const { return d_incomplete; }
 604
 605   /**
 606    * Returns true if we need another round of checking.  If this
 607    * returns true, check(FULL_EFFORT) _must_ be called by the
 608    * propositional layer before reporting SAT.
 609    *
 610    * This is especially necessary for incomplete theories that lazily
 611    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 612    * outputing quantifier instantiations).  In such a case, a lemma can
 613    * be asserted that is simplified away (perhaps it's already true).
 614    * However, we must maintain the invariant that, if a theory uses the
 615    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 616    * be performed before exit, even if no new facts are on its fact queue,
 617    * as it might decide to further instantiate some lemmas, precluding
 618    * a SAT response.
 619    */
 620   inline bool needCheck() const {
 621     return d_outputChannelUsed || d_lemmasAdded;
 622   }
 623
 624   /**
 625    * This is called at shutdown time by the SmtEngine, just before
 626    * destruction.  It is important because there are destruction
 627    * ordering issues between PropEngine and Theory.
 628    */
 629   void shutdown();
 630
 631   /**
 632    * Solve the given literal with a theory that owns it.
 633    */
 634   theory::Theory::PPAssertStatus solve(TNode literal,
 635                                     theory::SubstitutionMap& substitutionOut);
 636
 637   /**
 638    * Preregister a Theory atom with the responsible theory (or
 639    * theories).
 640    */
 641   void preRegister(TNode preprocessed);
 642
 643   /**
 644    * Assert the formula to the appropriate theory.
 645    * @param node the assertion
 646    */
 647   void assertFact(TNode node);
 648
 649   /**
 650    * Check all (currently-active) theories for conflicts.
 651    * @param effort the effort level to use
 652    */
 653   void check(theory::Theory::Effort effort);
 654
 655   /**
 656    * Run the combination framework.
 657    */
 658   void combineTheories();
 659
 660   /**
 661    * Calls ppStaticLearn() on all theories, accumulating their
 662    * combined contributions in the "learned" builder.
 663    */
 664   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 665
 666   /**
 667    * Calls presolve() on all theories and returns true
 668    * if one of the theories discovers a conflict.
 669    */
 670   bool presolve();
 671
 672    /**
 673    * Calls postsolve() on all theories.
 674    */
 675   void postsolve();
 676
 677   /**
 678    * Calls notifyRestart() on all active theories.
 679    */
 680   void notifyRestart();
 681
 682   void getPropagatedLiterals(std::vector<TNode>& literals) {
 683     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 684       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 685       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 686     }
 687   }
 688
 689   Node getNextDecisionRequest();
 690
 691   bool properConflict(TNode conflict) const;
 692   bool properPropagation(TNode lit) const;
 693   bool properExplanation(TNode node, TNode expl) const;
 694
 695   /**
 696    * Returns an explanation of the node propagated to the SAT solver.
 697    */
 698   Node getExplanation(TNode node);
 699
 700   /**
 701    * Returns an explanation of the node propagated to the SAT solver and the theory
 702    * that propagated it.
 703    */
 704   Node getExplanationAndRecipe(TNode node, LemmaProofRecipe* proofRecipe);
 705
 706   /**
 707    * collect model info
 708    */
 709   void collectModelInfo( theory::TheoryModel* m );
 710   /** post process model */
 711   void postProcessModel( theory::TheoryModel* m );
 712
 713   /**
 714    * Get the current model
 715    */
 716   theory::TheoryModel* getModel();
 717
 718   /**
 719    * Get the model builder
 720    */
 721   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 722
 723   /**
 724    * Get the theory associated to a given Node.
 725    *
 726    * @returns the theory, or NULL if the TNode is
 727    * of built-in type.
 728    */
 729   inline theory::Theory* theoryOf(TNode node) const {
 730     return d_theoryTable[theory::Theory::theoryOf(node)];
 731   }
 732
 733   /**
 734    * Get the theory associated to a the given theory id.
 735    *
 736    * @returns the theory
 737    */
 738   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 739     return d_theoryTable[theoryId];
 740   }
 741
 742   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 743     return d_logicInfo.isTheoryEnabled(theoryId);
 744   }
 745
 746   /**
 747    * Returns the equality status of the two terms, from the theory
 748    * that owns the domain type.  The types of a and b must be the same.
 749    */
 750   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 751
 752   /**
 753    * Returns the value that a theory that owns the type of var currently
 754    * has (or null if none);
 755    */
 756   Node getModelValue(TNode var);
 757
 758   /**
 759    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 760    */
 761   Node ensureLiteral(TNode n);
 762
 763   /**
 764    * Print all instantiations made by the quantifiers module.
 765    */
 766   void printInstantiations( std::ostream& out );
 767
 768   /**
 769    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 770    */
 771   void printSynthSolution( std::ostream& out );
 772
 773   /**
 774    * Get list of quantified formulas that were instantiated
 775    */
 776   void getInstantiatedQuantifiedFormulas( std::vector< Node >& qs );
 777
 778   /**
 779    * Get instantiation methods
 780    *   first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
 781    *   second inputs forall x.q[x] and returns ( a, ..., z )
 782    *   third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] ) , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
 783    */
 784   void getInstantiations( Node q, std::vector< Node >& insts );
 785   void getInstantiationTermVectors( Node q, std::vector< std::vector< Node > >& tvecs );
 786   void getInstantiations( std::map< Node, std::vector< Node > >& insts );
 787   void getInstantiationTermVectors( std::map< Node, std::vector< std::vector< Node > > >& insts );
 788
 789   /**
 790    * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
 791    *   Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
 792    */
 793   Node getInstantiatedConjunction( Node q );
 794
 795   /**
 796    * Forwards an entailment check according to the given theoryOfMode.
 797    * See theory.h for documentation on entailmentCheck().
 798    */
 799   std::pair<bool, Node> entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL);
 800
 801 private:
 802
 803   /** Default visitor for pre-registration */
 804   PreRegisterVisitor d_preRegistrationVisitor;
 805
 806   /** Visitor for collecting shared terms */
 807   SharedTermsVisitor d_sharedTermsVisitor;
 808
 809   /** Dump the assertions to the dump */
 810   void dumpAssertions(const char* tag);
 811
 812   /**
 813    * A collection of ite preprocessing passes.
 814    */
 815   theory::ITEUtilities* d_iteUtilities;
 816
 817
 818   /** For preprocessing pass simplifying unconstrained expressions */
 819   UnconstrainedSimplifier* d_unconstrainedSimp;
 820
 821   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 822   theory::bv::BvToBoolPreprocessor d_bvToBoolPreprocessor;
 823 public:
 824   void staticInitializeBVOptions(const std::vector<Node>& assertions);
 825   void ppBvToBool(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 826   void ppBoolToBv(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 827   bool ppBvAbstraction(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 828   void mkAckermanizationAssertions(std::vector<Node>& assertions);
 829
 830   Node ppSimpITE(TNode assertion);
 831   /** Returns false if an assertion simplified to false. */
 832   bool donePPSimpITE(std::vector<Node>& assertions);
 833
 834   void ppUnconstrainedSimp(std::vector<Node>& assertions);
 835
 836   SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; }
 837
 838   theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; }
 839
 840   RemoveTermFormulas* getTermFormulaRemover() { return &d_tform_remover; }
 841
 842   SortInference* getSortInference() { return &d_sortInfer; }
 843
 844   /** Prints the assertions to the debug stream */
 845   void printAssertions(const char* tag);
 846
 847   /** Theory alternative is in use. */
 848   bool useTheoryAlternative(const std::string& name);
 849
 850   /** Enables using a theory alternative by name. */
 851   void enableTheoryAlternative(const std::string& name);
 852
 853 private:
 854   std::set< std::string > d_theoryAlternatives;
 855
 856   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 857 public:
 858
 859   /**
 860    * Set user attribute.
 861    * This function is called when an attribute is set by a user.  In SMT-LIBv2 this is done
 862    * via the syntax (! n :attr)
 863    */
 864   void setUserAttribute(const std::string& attr, Node n, std::vector<Node>& node_values, std::string str_value);
 865
 866   /**
 867    * Handle user attribute.
 868    * Associates theory t with the attribute attr.  Theory t will be
 869    * notified whenever an attribute of name attr is set.
 870    */
 871   void handleUserAttribute(const char* attr, theory::Theory* t);
 872
 873   /**
 874    * Check that the theory assertions are satisfied in the model.
 875    * This function is called from the smt engine's checkModel routine.
 876    */
 877   void checkTheoryAssertionsWithModel(bool hardFailure);
 878
 879 private:
 880   IntStat d_arithSubstitutionsAdded;
 881
 882 };/* class TheoryEngine */
 883
 884 }/* CVC4 namespace */
 885
 886 #endif /* __CVC4__THEORY_ENGINE_H */