src/theory/theory_engine.h

   1 /*********************                                                        */
   2 /*! \file theory_engine.h
   3  ** \verbatim
   4  ** Original author: Morgan Deters
   5  ** Major contributors: Andrew Reynolds, Dejan Jovanovic
   6  ** Minor contributors (to current version): Christopher L. Conway, Francois Bobot, Kshitij Bansal, Clark Barrett, Liana Hadarean, Tim King
   7  ** This file is part of the CVC4 project.
   8  ** Copyright (c) 2009-2014  New York University and The University of Iowa
   9  ** See the file COPYING in the top-level source directory for licensing
  10  ** 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 <vector>
  25 #include <utility>
  26
  27 #include "base/cvc4_assert.h"
  28 #include "context/cdhashset.h"
  29 #include "expr/node.h"
  30 #include "options/options.h"
  31 #include "options/smt_options.h"
  32 #include "prop/prop_engine.h"
  33 #include "smt_util/command.h"
  34 #include "smt_util/lemma_channels.h"
  35 #include "theory/atom_requests.h"
  36 #include "theory/bv/bv_to_bool.h"
  37 #include "theory/interrupted.h"
  38 #include "theory/quantifiers/quant_conflict_find.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/statistics_registry.h"
  48 #include "util/unsafe_interrupt_exception.h"
  49
  50 namespace CVC4 {
  51
  52 class ResourceManager;
  53
  54 /**
  55  * A pair of a theory and a node. This is used to mark the flow of
  56  * propagations between theories.
  57  */
  58 struct NodeTheoryPair {
  59   Node node;
  60   theory::TheoryId theory;
  61   size_t timestamp;
  62   NodeTheoryPair(TNode node, theory::TheoryId theory, size_t timestamp)
  63   : node(node), theory(theory), timestamp(timestamp) {}
  64   NodeTheoryPair()
  65   : theory(theory::THEORY_LAST) {}
  66   // Comparison doesn't take into account the timestamp
  67   bool operator == (const NodeTheoryPair& pair) const {
  68     return node == pair.node && theory == pair.theory;
  69   }
  70 };/* struct NodeTheoryPair */
  71
  72 struct NodeTheoryPairHashFunction {
  73   NodeHashFunction hashFunction;
  74   // Hash doesn't take into account the timestamp
  75   size_t operator()(const NodeTheoryPair& pair) const {
  76     return hashFunction(pair.node)*0x9e3779b9 + pair.theory;
  77   }
  78 };/* struct NodeTheoryPairHashFunction */
  79
  80
  81 /* Forward declarations */
  82 namespace theory {
  83   class TheoryModel;
  84   class TheoryEngineModelBuilder;
  85   class ITEUtilities;
  86
  87   namespace eq {
  88     class EqualityEngine;
  89   }/* CVC4::theory::eq namespace */
  90
  91   namespace quantifiers {
  92     class TermDb;
  93   }
  94
  95   class EntailmentCheckParameters;
  96   class EntailmentCheckSideEffects;
  97 }/* CVC4::theory namespace */
  98
  99 class DecisionEngine;
 100 class RemoveITE;
 101 class UnconstrainedSimplifier;
 102
 103 /**
 104  * This is essentially an abstraction for a collection of theories.  A
 105  * TheoryEngine provides services to a PropEngine, making various
 106  * T-solvers look like a single unit to the propositional part of
 107  * CVC4.
 108  */
 109 class TheoryEngine {
 110
 111   /** Shared terms database can use the internals notify the theories */
 112   friend class SharedTermsDatabase;
 113   friend class theory::quantifiers::TermDb;
 114
 115   /** Associated PropEngine engine */
 116   prop::PropEngine* d_propEngine;
 117
 118   /** Access to decision engine */
 119   DecisionEngine* d_decisionEngine;
 120
 121   /** Our context */
 122   context::Context* d_context;
 123
 124   /** Our user context */
 125   context::UserContext* d_userContext;
 126
 127   /**
 128    * A table of from theory IDs to theory pointers. Never use this table
 129    * directly, use theoryOf() instead.
 130    */
 131   theory::Theory* d_theoryTable[theory::THEORY_LAST];
 132
 133   /**
 134    * A collection of theories that are "active" for the current run.
 135    * This set is provided by the user (as a logic string, say, in SMT-LIBv2
 136    * format input), or else by default it's all-inclusive.  This is important
 137    * because we can optimize for single-theory runs (no sharing), can reduce
 138    * the cost of walking the DAG on registration, etc.
 139    */
 140   const LogicInfo& d_logicInfo;
 141
 142   /**
 143    * The database of shared terms.
 144    */
 145   SharedTermsDatabase d_sharedTerms;
 146
 147   /**
 148    * Master equality engine, to share with theories.
 149    */
 150   theory::eq::EqualityEngine* d_masterEqualityEngine;
 151
 152   /** notify class for master equality engine */
 153   class NotifyClass : public theory::eq::EqualityEngineNotify {
 154     TheoryEngine& d_te;
 155   public:
 156     NotifyClass(TheoryEngine& te): d_te(te) {}
 157     bool eqNotifyTriggerEquality(TNode equality, bool value) { return true; }
 158     bool eqNotifyTriggerPredicate(TNode predicate, bool value) { return true; }
 159     bool eqNotifyTriggerTermEquality(theory::TheoryId tag, TNode t1, TNode t2, bool value) { return true; }
 160     void eqNotifyConstantTermMerge(TNode t1, TNode t2) {}
 161     void eqNotifyNewClass(TNode t) { d_te.eqNotifyNewClass(t); }
 162     void eqNotifyPreMerge(TNode t1, TNode t2) { d_te.eqNotifyPreMerge(t1, t2); }
 163     void eqNotifyPostMerge(TNode t1, TNode t2) { d_te.eqNotifyPostMerge(t1, t2); }
 164     void eqNotifyDisequal(TNode t1, TNode t2, TNode reason) { d_te.eqNotifyDisequal(t1, t2, reason); }
 165   };/* class TheoryEngine::NotifyClass */
 166   NotifyClass d_masterEENotify;
 167
 168   /**
 169    * notification methods
 170    */
 171   void eqNotifyNewClass(TNode t);
 172   void eqNotifyPreMerge(TNode t1, TNode t2);
 173   void eqNotifyPostMerge(TNode t1, TNode t2);
 174   void eqNotifyDisequal(TNode t1, TNode t2, TNode reason);
 175
 176   /**
 177    * The quantifiers engine
 178    */
 179   theory::QuantifiersEngine* d_quantEngine;
 180
 181   /**
 182    * Default model object
 183    */
 184   theory::TheoryModel* d_curr_model;
 185   /**
 186    * Model builder object
 187    */
 188   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 189
 190   typedef std::hash_map<Node, Node, NodeHashFunction> NodeMap;
 191   typedef std::hash_map<TNode, Node, TNodeHashFunction> TNodeMap;
 192
 193   /**
 194   * Cache for theory-preprocessing of assertions
 195    */
 196   NodeMap d_ppCache;
 197
 198   /**
 199    * Used for "missed-t-propagations" dumping mode only.  A set of all
 200    * theory-propagable literals.
 201    */
 202   context::CDList<TNode> d_possiblePropagations;
 203
 204   /**
 205    * Used for "missed-t-propagations" dumping mode only.  A
 206    * context-dependent set of those theory-propagable literals that
 207    * have been propagated.
 208    */
 209   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 210
 211
 212   /**
 213    * Statistics for a particular theory.
 214    */
 215   class Statistics {
 216
 217     static std::string mkName(std::string prefix,
 218                               theory::TheoryId theory,
 219                               std::string suffix) {
 220       std::stringstream ss;
 221       ss << prefix << theory << suffix;
 222       return ss.str();
 223     }
 224
 225   public:
 226
 227     IntStat conflicts, propagations, lemmas, requirePhase, flipDecision, restartDemands;
 228
 229     Statistics(theory::TheoryId theory);
 230     ~Statistics();
 231   };/* class TheoryEngine::Statistics */
 232
 233
 234   /**
 235    * An output channel for Theory that passes messages
 236    * back to a TheoryEngine.
 237    */
 238   class EngineOutputChannel : public theory::OutputChannel {
 239
 240     friend class TheoryEngine;
 241
 242     /**
 243      * The theory engine we're communicating with.
 244      */
 245     TheoryEngine* d_engine;
 246
 247     /**
 248      * The statistics of the theory interractions.
 249      */
 250     Statistics d_statistics;
 251
 252     /**
 253      * The theory owning this chanell.
 254      */
 255     theory::TheoryId d_theory;
 256
 257   public:
 258
 259     EngineOutputChannel(TheoryEngine* engine, theory::TheoryId theory) :
 260       d_engine(engine),
 261       d_statistics(theory),
 262       d_theory(theory)
 263     {
 264     }
 265
 266       void safePoint(uint64_t ammount) throw(theory::Interrupted, UnsafeInterruptException, AssertionException) {
 267       spendResource(ammount);
 268       if (d_engine->d_interrupted) {
 269         throw theory::Interrupted();
 270       }
 271     }
 272
 273     void conflict(TNode conflictNode, Proof* pf = NULL) throw(AssertionException, UnsafeInterruptException) {
 274       Trace("theory::conflict") << "EngineOutputChannel<" << d_theory << ">::conflict(" << conflictNode << ")" << std::endl;
 275       Assert(pf == NULL); // theory shouldn't be producing proofs yet
 276       ++ d_statistics.conflicts;
 277       d_engine->d_outputChannelUsed = true;
 278       d_engine->conflict(conflictNode, d_theory);
 279     }
 280
 281     bool propagate(TNode literal) throw(AssertionException, UnsafeInterruptException) {
 282       Trace("theory::propagate") << "EngineOutputChannel<" << d_theory << ">::propagate(" << literal << ")" << std::endl;
 283       ++ d_statistics.propagations;
 284       d_engine->d_outputChannelUsed = true;
 285       return d_engine->propagate(literal, d_theory);
 286     }
 287
 288     theory::LemmaStatus lemma(TNode lemma,
 289                               ProofRule rule,
 290                               bool removable = false,
 291                               bool preprocess = false,
 292                               bool sendAtoms = false)
 293       throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) {
 294       Trace("theory::lemma") << "EngineOutputChannel<" << d_theory << ">::lemma(" << lemma << ")" << std::endl;
 295       ++ d_statistics.lemmas;
 296       d_engine->d_outputChannelUsed = true;
 297       return d_engine->lemma(lemma, rule, false, removable, preprocess, sendAtoms ? d_theory: theory::THEORY_LAST);
 298     }
 299
 300     theory::LemmaStatus splitLemma(TNode lemma, bool removable = false) throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) {
 301       Trace("theory::lemma") << "EngineOutputChannel<" << d_theory << ">::lemma(" << lemma << ")" << std::endl;
 302       ++ d_statistics.lemmas;
 303       d_engine->d_outputChannelUsed = true;
 304       return d_engine->lemma(lemma, RULE_SPLIT, false, removable, false, d_theory);
 305     }
 306
 307     void demandRestart() throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) {
 308       NodeManager* curr = NodeManager::currentNM();
 309       Node restartVar =  curr->mkSkolem("restartVar",
 310                                         curr->booleanType(),
 311                                         "A boolean variable asserted to be true to force a restart");
 312       Trace("theory::restart") << "EngineOutputChannel<" << d_theory << ">::restart(" << restartVar << ")" << std::endl;
 313       ++ d_statistics.restartDemands;
 314       lemma(restartVar, RULE_INVALID, true);
 315     }
 316
 317     void requirePhase(TNode n, bool phase)
 318       throw(theory::Interrupted, AssertionException, UnsafeInterruptException) {
 319       Debug("theory") << "EngineOutputChannel::requirePhase("
 320                       << n << ", " << phase << ")" << std::endl;
 321       ++ d_statistics.requirePhase;
 322       d_engine->d_propEngine->requirePhase(n, phase);
 323     }
 324
 325     bool flipDecision()
 326       throw(theory::Interrupted, AssertionException, UnsafeInterruptException) {
 327       Debug("theory") << "EngineOutputChannel::flipDecision()" << std::endl;
 328       ++ d_statistics.flipDecision;
 329       return d_engine->d_propEngine->flipDecision();
 330     }
 331
 332     void setIncomplete() throw(AssertionException, UnsafeInterruptException) {
 333       Trace("theory") << "TheoryEngine::setIncomplete()" << std::endl;
 334       d_engine->setIncomplete(d_theory);
 335     }
 336
 337     void spendResource(unsigned ammount) throw(UnsafeInterruptException) {
 338       d_engine->spendResource(ammount);
 339     }
 340
 341     void handleUserAttribute( const char* attr, theory::Theory* t ){
 342       d_engine->handleUserAttribute( attr, t );
 343     }
 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    * Called by the output channel to request decisions "as soon as
 418    * possible."
 419    */
 420   void propagateAsDecision(TNode literal, theory::TheoryId theory);
 421
 422   /**
 423    * A variable to mark if we added any lemmas.
 424    */
 425   bool d_lemmasAdded;
 426
 427   /**
 428    * A variable to mark if the OutputChannel was "used" by any theory
 429    * since the start of the last check.  If it has been, we require
 430    * a FULL_EFFORT check before exiting and reporting SAT.
 431    *
 432    * See the documentation for the needCheck() function, below.
 433    */
 434   bool d_outputChannelUsed;
 435
 436   /** Atom requests from lemmas */
 437   AtomRequests d_atomRequests;
 438
 439   /**
 440    * Adds a new lemma, returning its status.
 441    * @param node the lemma
 442    * @param negated should the lemma be asserted negated
 443    * @param removable can the lemma be remove (restrictions apply)
 444    * @param needAtoms if not THEORY_LAST, then
 445    */
 446   theory::LemmaStatus lemma(TNode node,
 447                             ProofRule rule,
 448                             bool negated,
 449                             bool removable,
 450                             bool preprocess,
 451                             theory::TheoryId atomsTo);
 452
 453   /** Enusre that the given atoms are send to the given theory */
 454   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 455
 456   RemoveITE& d_iteRemover;
 457
 458   /** sort inference module */
 459   SortInference d_sortInfer;
 460
 461   /** Time spent in theory combination */
 462   TimerStat d_combineTheoriesTime;
 463
 464   Node d_true;
 465   Node d_false;
 466
 467   /** Whether we were just interrupted (or not) */
 468   bool d_interrupted;
 469   ResourceManager* d_resourceManager;
 470
 471   /** Container for lemma input and output channels. */
 472   LemmaChannels* d_channels;
 473
 474 public:
 475
 476   /** Constructs a theory engine */
 477   TheoryEngine(context::Context* context, context::UserContext* userContext,
 478                RemoveITE& iteRemover, const LogicInfo& logic,
 479                LemmaChannels* channels);
 480
 481   /** Destroys a theory engine */
 482   ~TheoryEngine();
 483
 484   void interrupt() throw(ModalException);
 485   /**
 486    * "Spend" a resource during a search or preprocessing.
 487    */
 488   void spendResource(unsigned ammount);
 489
 490   /**
 491    * Adds a theory. Only one theory per TheoryId can be present, so if
 492    * there is another theory it will be deleted.
 493    */
 494   template <class TheoryClass>
 495   inline void addTheory(theory::TheoryId theoryId) {
 496     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 497     d_theoryOut[theoryId] = new EngineOutputChannel(this, theoryId);
 498     d_theoryTable[theoryId] =
 499         new TheoryClass(d_context, d_userContext, *d_theoryOut[theoryId],
 500                         theory::Valuation(this), d_logicInfo);
 501   }
 502
 503   inline void setPropEngine(prop::PropEngine* propEngine) {
 504     Assert(d_propEngine == NULL);
 505     d_propEngine = propEngine;
 506   }
 507
 508   inline void setDecisionEngine(DecisionEngine* decisionEngine) {
 509     Assert(d_decisionEngine == NULL);
 510     d_decisionEngine = decisionEngine;
 511   }
 512
 513   /** Called when all initialization of options/logic is done */
 514   void finishInit();
 515
 516   /**
 517    * Get a pointer to the underlying propositional engine.
 518    */
 519   inline prop::PropEngine* getPropEngine() const {
 520     return d_propEngine;
 521   }
 522
 523   /**
 524    * Get a pointer to the underlying sat context.
 525    */
 526   inline context::Context* getSatContext() const {
 527     return d_context;
 528   }
 529
 530   /**
 531    * Get a pointer to the underlying user context.
 532    */
 533   inline context::Context* getUserContext() const {
 534     return d_userContext;
 535   }
 536
 537   /**
 538    * Get a pointer to the underlying quantifiers engine.
 539    */
 540   theory::QuantifiersEngine* getQuantifiersEngine() const {
 541     return d_quantEngine;
 542   }
 543
 544 private:
 545
 546   /**
 547    * Helper for preprocess
 548    */
 549   Node ppTheoryRewrite(TNode term);
 550
 551   /**
 552    * Queue of nodes for pre-registration.
 553    */
 554   std::queue<TNode> d_preregisterQueue;
 555
 556   /**
 557    * Boolean flag denoting we are in pre-registration.
 558    */
 559   bool d_inPreregister;
 560
 561   /**
 562    * Did the theories get any new facts since the last time we called
 563    * check()
 564    */
 565   context::CDO<bool> d_factsAsserted;
 566
 567   /**
 568    * Map from equality atoms to theories that would like to be notified about them.
 569    */
 570
 571
 572   /**
 573    * Assert the formula to the given theory.
 574    * @param assertion the assertion to send (not necesserily normalized)
 575    * @param original the assertion as it was sent in from the propagating theory
 576    * @param toTheoryId the theory to assert to
 577    * @param fromTheoryId the theory that sent it
 578    */
 579   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 580
 581   /**
 582    * Marks a theory propagation from a theory to a theory where a
 583    * theory could be the THEORY_SAT_SOLVER for literals coming from
 584    * or being propagated to the SAT solver. If the receiving theory
 585    * already recieved the literal, the method returns false, otherwise
 586    * it returns true.
 587    *
 588    * @param assertion the normalized assertion being sent
 589    * @param originalAssertion the actual assertion that was sent
 590    * @param toTheoryId the theory that is on the receiving end
 591    * @param fromTheoryId the theory that sent the assertino
 592    * @return true if a new assertion, false if theory already got it
 593    */
 594   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 595
 596   /**
 597    * Computes the explanation by travarsing the propagation graph and
 598    * asking relevant theories to explain the propagations. Initially
 599    * the explanation vector should contain only the element (node, theory)
 600    * where the node is the one to be explained, and the theory is the
 601    * theory that sent the literal.
 602    */
 603   void getExplanation(std::vector<NodeTheoryPair>& explanationVector);
 604
 605 public:
 606
 607   /**
 608    * Signal the start of a new round of assertion preprocessing
 609    */
 610   void preprocessStart();
 611
 612   /**
 613    * Runs theory specific preprocessing on the non-Boolean parts of
 614    * the formula.  This is only called on input assertions, after ITEs
 615    * have been removed.
 616    */
 617   Node preprocess(TNode node);
 618
 619   /**
 620    * Return whether or not we are incomplete (in the current context).
 621    */
 622   inline bool isIncomplete() const {
 623     return d_incomplete;
 624   }
 625
 626   /**
 627    * Returns true if we need another round of checking.  If this
 628    * returns true, check(FULL_EFFORT) _must_ be called by the
 629    * propositional layer before reporting SAT.
 630    *
 631    * This is especially necessary for incomplete theories that lazily
 632    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 633    * outputing quantifier instantiations).  In such a case, a lemma can
 634    * be asserted that is simplified away (perhaps it's already true).
 635    * However, we must maintain the invariant that, if a theory uses the
 636    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 637    * be performed before exit, even if no new facts are on its fact queue,
 638    * as it might decide to further instantiate some lemmas, precluding
 639    * a SAT response.
 640    */
 641   inline bool needCheck() const {
 642     return d_outputChannelUsed || d_lemmasAdded;
 643   }
 644
 645   /**
 646    * This is called at shutdown time by the SmtEngine, just before
 647    * destruction.  It is important because there are destruction
 648    * ordering issues between PropEngine and Theory.
 649    */
 650   void shutdown();
 651
 652   /**
 653    * Solve the given literal with a theory that owns it.
 654    */
 655   theory::Theory::PPAssertStatus solve(TNode literal,
 656                                     theory::SubstitutionMap& substitutionOut);
 657
 658   /**
 659    * Preregister a Theory atom with the responsible theory (or
 660    * theories).
 661    */
 662   void preRegister(TNode preprocessed);
 663
 664   /**
 665    * Assert the formula to the appropriate theory.
 666    * @param node the assertion
 667    */
 668   void assertFact(TNode node);
 669
 670   /**
 671    * Check all (currently-active) theories for conflicts.
 672    * @param effort the effort level to use
 673    */
 674   void check(theory::Theory::Effort effort);
 675
 676   /**
 677    * Run the combination framework.
 678    */
 679   void combineTheories();
 680
 681   /**
 682    * Calls ppStaticLearn() on all theories, accumulating their
 683    * combined contributions in the "learned" builder.
 684    */
 685   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 686
 687   /**
 688    * Calls presolve() on all theories and returns true
 689    * if one of the theories discovers a conflict.
 690    */
 691   bool presolve();
 692
 693    /**
 694    * Calls postsolve() on all theories.
 695    */
 696   void postsolve();
 697
 698   /**
 699    * Calls notifyRestart() on all active theories.
 700    */
 701   void notifyRestart();
 702
 703   void getPropagatedLiterals(std::vector<TNode>& literals) {
 704     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 705       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 706       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 707     }
 708   }
 709
 710   Node getNextDecisionRequest();
 711
 712   bool properConflict(TNode conflict) const;
 713   bool properPropagation(TNode lit) const;
 714   bool properExplanation(TNode node, TNode expl) const;
 715
 716   /**
 717    * Returns an explanation of the node propagated to the SAT solver.
 718    */
 719   Node getExplanation(TNode node);
 720
 721   /**
 722    * collect model info
 723    */
 724   void collectModelInfo( theory::TheoryModel* m, bool fullModel );
 725
 726   /**
 727    * Get the current model
 728    */
 729   theory::TheoryModel* getModel();
 730
 731   /**
 732    * Get the model builder
 733    */
 734   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 735
 736   /**
 737    * Get the theory associated to a given Node.
 738    *
 739    * @returns the theory, or NULL if the TNode is
 740    * of built-in type.
 741    */
 742   inline theory::Theory* theoryOf(TNode node) const {
 743     return d_theoryTable[theory::Theory::theoryOf(node)];
 744   }
 745
 746   /**
 747    * Get the theory associated to a the given theory id.
 748    *
 749    * @returns the theory
 750    */
 751   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 752     return d_theoryTable[theoryId];
 753   }
 754
 755   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 756     return d_logicInfo.isTheoryEnabled(theoryId);
 757   }
 758
 759   /**
 760    * Returns the equality status of the two terms, from the theory
 761    * that owns the domain type.  The types of a and b must be the same.
 762    */
 763   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 764
 765   /**
 766    * Returns the value that a theory that owns the type of var currently
 767    * has (or null if none);
 768    */
 769   Node getModelValue(TNode var);
 770
 771   /**
 772    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 773    */
 774   Node ensureLiteral(TNode n);
 775
 776   /**
 777    * Print all instantiations made by the quantifiers module.
 778    */
 779   void printInstantiations( std::ostream& out );
 780
 781   /**
 782    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 783    */
 784   void printSynthSolution( std::ostream& out );
 785
 786   /**
 787    * Forwards an entailment check according to the given theoryOfMode.
 788    * See theory.h for documentation on entailmentCheck().
 789    */
 790   std::pair<bool, Node> entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL);
 791
 792 private:
 793
 794   /** Default visitor for pre-registration */
 795   PreRegisterVisitor d_preRegistrationVisitor;
 796
 797   /** Visitor for collecting shared terms */
 798   SharedTermsVisitor d_sharedTermsVisitor;
 799
 800   /** Dump the assertions to the dump */
 801   void dumpAssertions(const char* tag);
 802
 803   /**
 804    * A collection of ite preprocessing passes.
 805    */
 806   theory::ITEUtilities* d_iteUtilities;
 807
 808
 809   /** For preprocessing pass simplifying unconstrained expressions */
 810   UnconstrainedSimplifier* d_unconstrainedSimp;
 811
 812   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 813   theory::bv::BvToBoolPreprocessor d_bvToBoolPreprocessor;
 814 public:
 815   void staticInitializeBVOptions(const std::vector<Node>& assertions);
 816   void ppBvToBool(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 817   bool ppBvAbstraction(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 818   void mkAckermanizationAsssertions(std::vector<Node>& assertions);
 819
 820   Node ppSimpITE(TNode assertion);
 821   /** Returns false if an assertion simplified to false. */
 822   bool donePPSimpITE(std::vector<Node>& assertions);
 823
 824   void ppUnconstrainedSimp(std::vector<Node>& assertions);
 825
 826   SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; }
 827
 828   theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; }
 829
 830   RemoveITE* getIteRemover() { return &d_iteRemover; }
 831
 832   SortInference* getSortInference() { return &d_sortInfer; }
 833
 834   /** Prints the assertions to the debug stream */
 835   void printAssertions(const char* tag);
 836
 837   /** Theory alternative is in use. */
 838   bool useTheoryAlternative(const std::string& name);
 839
 840   /** Enables using a theory alternative by name. */
 841   void enableTheoryAlternative(const std::string& name);
 842
 843 private:
 844   std::set< std::string > d_theoryAlternatives;
 845
 846   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 847 public:
 848
 849   /**
 850    * Set user attribute.
 851    * This function is called when an attribute is set by a user.  In SMT-LIBv2 this is done
 852    * via the syntax (! n :attr)
 853    */
 854   void setUserAttribute(const std::string& attr, Node n, std::vector<Node> node_values, std::string str_value);
 855
 856   /**
 857    * Handle user attribute.
 858    * Associates theory t with the attribute attr.  Theory t will be
 859    * notified whenever an attribute of name attr is set.
 860    */
 861   void handleUserAttribute(const char* attr, theory::Theory* t);
 862
 863   /**
 864    * Check that the theory assertions are satisfied in the model.
 865    * This function is called from the smt engine's checkModel routine.
 866    */
 867   void checkTheoryAssertionsWithModel();
 868
 869 private:
 870   IntStat d_arithSubstitutionsAdded;
 871
 872 };/* class TheoryEngine */
 873
 874 }/* CVC4 namespace */
 875
 876 #endif /* __CVC4__THEORY_ENGINE_H */