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) 2009-2016 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 <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/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/rewriter.h"
  39 #include "theory/shared_terms_database.h"
  40 #include "theory/sort_inference.h"
  41 #include "theory/substitutions.h"
  42 #include "theory/term_registration_visitor.h"
  43 #include "theory/theory.h"
  44 #include "theory/uf/equality_engine.h"
  45 #include "theory/valuation.h"
  46 #include "util/statistics_registry.h"
  47 #include "util/unsafe_interrupt_exception.h"
  48
  49 namespace CVC4 {
  50
  51 class ResourceManager;
  52 class LemmaProofRecipe;
  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 = 0)
  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   bool d_aloc_curr_model;
 186   /**
 187    * Model builder object
 188    */
 189   theory::TheoryEngineModelBuilder* d_curr_model_builder;
 190
 191   typedef std::hash_map<Node, Node, NodeHashFunction> NodeMap;
 192   typedef std::hash_map<TNode, Node, TNodeHashFunction> TNodeMap;
 193
 194   /**
 195   * Cache for theory-preprocessing of assertions
 196    */
 197   NodeMap d_ppCache;
 198
 199   /**
 200    * Used for "missed-t-propagations" dumping mode only.  A set of all
 201    * theory-propagable literals.
 202    */
 203   context::CDList<TNode> d_possiblePropagations;
 204
 205   /**
 206    * Used for "missed-t-propagations" dumping mode only.  A
 207    * context-dependent set of those theory-propagable literals that
 208    * have been propagated.
 209    */
 210   context::CDHashSet<Node, NodeHashFunction> d_hasPropagated;
 211
 212
 213   /**
 214    * Statistics for a particular theory.
 215    */
 216   class Statistics {
 217
 218     static std::string mkName(std::string prefix,
 219                               theory::TheoryId theory,
 220                               std::string suffix) {
 221       std::stringstream ss;
 222       ss << prefix << theory << suffix;
 223       return ss.str();
 224     }
 225
 226   public:
 227
 228     IntStat conflicts, propagations, lemmas, requirePhase, flipDecision, restartDemands;
 229
 230     Statistics(theory::TheoryId theory);
 231     ~Statistics();
 232   };/* class TheoryEngine::Statistics */
 233
 234
 235   /**
 236    * An output channel for Theory that passes messages
 237    * back to a TheoryEngine.
 238    */
 239   class EngineOutputChannel : public theory::OutputChannel {
 240
 241     friend class TheoryEngine;
 242
 243     /**
 244      * The theory engine we're communicating with.
 245      */
 246     TheoryEngine* d_engine;
 247
 248     /**
 249      * The statistics of the theory interractions.
 250      */
 251     Statistics d_statistics;
 252
 253     /**
 254      * The theory owning this chanell.
 255      */
 256     theory::TheoryId d_theory;
 257
 258   public:
 259
 260     EngineOutputChannel(TheoryEngine* engine, theory::TheoryId theory) :
 261       d_engine(engine),
 262       d_statistics(theory),
 263       d_theory(theory)
 264     {
 265     }
 266
 267     void safePoint(uint64_t ammount) throw(theory::Interrupted, UnsafeInterruptException, AssertionException) {
 268       spendResource(ammount);
 269       if (d_engine->d_interrupted) {
 270         throw theory::Interrupted();
 271       }
 272     }
 273
 274     void conflict(TNode conflictNode, Proof* pf = NULL) throw(AssertionException, UnsafeInterruptException);
 275
 276     bool propagate(TNode literal) throw(AssertionException, UnsafeInterruptException);
 277
 278     theory::LemmaStatus lemma(TNode lemma,
 279                               ProofRule rule,
 280                               bool removable = false,
 281                               bool preprocess = false,
 282                               bool sendAtoms = false)
 283       throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException);
 284
 285     theory::LemmaStatus splitLemma(TNode lemma, bool removable = false) throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException);
 286
 287     void demandRestart() throw(TypeCheckingExceptionPrivate, AssertionException, UnsafeInterruptException) {
 288       NodeManager* curr = NodeManager::currentNM();
 289       Node restartVar =  curr->mkSkolem("restartVar",
 290                                         curr->booleanType(),
 291                                         "A boolean variable asserted to be true to force a restart");
 292       Trace("theory::restart") << "EngineOutputChannel<" << d_theory << ">::restart(" << restartVar << ")" << std::endl;
 293       ++ d_statistics.restartDemands;
 294       lemma(restartVar, RULE_INVALID, true);
 295     }
 296
 297     void requirePhase(TNode n, bool phase)
 298       throw(theory::Interrupted, AssertionException, UnsafeInterruptException) {
 299       Debug("theory") << "EngineOutputChannel::requirePhase("
 300                       << n << ", " << phase << ")" << std::endl;
 301       ++ d_statistics.requirePhase;
 302       d_engine->d_propEngine->requirePhase(n, phase);
 303     }
 304
 305     bool flipDecision()
 306       throw(theory::Interrupted, AssertionException, UnsafeInterruptException) {
 307       Debug("theory") << "EngineOutputChannel::flipDecision()" << std::endl;
 308       ++ d_statistics.flipDecision;
 309       return d_engine->d_propEngine->flipDecision();
 310     }
 311
 312     void setIncomplete() throw(AssertionException, UnsafeInterruptException) {
 313       Trace("theory") << "TheoryEngine::setIncomplete()" << std::endl;
 314       d_engine->setIncomplete(d_theory);
 315     }
 316
 317     void spendResource(unsigned ammount) throw(UnsafeInterruptException) {
 318       d_engine->spendResource(ammount);
 319     }
 320
 321     void handleUserAttribute( const char* attr, theory::Theory* t ){
 322       d_engine->handleUserAttribute( attr, t );
 323     }
 324
 325   private:
 326
 327     /**
 328      * A helper function for registering lemma recipes with the proof engine
 329      */
 330     void registerLemmaRecipe(Node lemma, Node originalLemma, bool preprocess, theory::TheoryId theoryId);
 331   };/* class TheoryEngine::EngineOutputChannel */
 332
 333   /**
 334    * Output channels for individual theories.
 335    */
 336   EngineOutputChannel* d_theoryOut[theory::THEORY_LAST];
 337
 338   /**
 339    * Are we in conflict.
 340    */
 341   context::CDO<bool> d_inConflict;
 342
 343   /**
 344    * Called by the theories to notify of a conflict.
 345    */
 346   void conflict(TNode conflict, theory::TheoryId theoryId);
 347
 348   /**
 349    * Debugging flag to ensure that shutdown() is called before the
 350    * destructor.
 351    */
 352   bool d_hasShutDown;
 353
 354   /**
 355    * True if a theory has notified us of incompleteness (at this
 356    * context level or below).
 357    */
 358   context::CDO<bool> d_incomplete;
 359
 360   /**
 361    * Called by the theories to notify that the current branch is incomplete.
 362    */
 363   void setIncomplete(theory::TheoryId theory) {
 364     d_incomplete = true;
 365   }
 366
 367
 368   /**
 369    * Mapping of propagations from recievers to senders.
 370    */
 371   typedef context::CDHashMap<NodeTheoryPair, NodeTheoryPair, NodeTheoryPairHashFunction> PropagationMap;
 372   PropagationMap d_propagationMap;
 373
 374   /**
 375    * Timestamp of propagations
 376    */
 377   context::CDO<size_t> d_propagationMapTimestamp;
 378
 379   /**
 380    * Literals that are propagated by the theory. Note that these are TNodes.
 381    * The theory can only propagate nodes that have an assigned literal in the
 382    * SAT solver and are hence referenced in the SAT solver.
 383    */
 384   context::CDList<TNode> d_propagatedLiterals;
 385
 386   /**
 387    * The index of the next literal to be propagated by a theory.
 388    */
 389   context::CDO<unsigned> d_propagatedLiteralsIndex;
 390
 391   /**
 392    * Called by the output channel to propagate literals and facts
 393    * @return false if immediate conflict
 394    */
 395   bool propagate(TNode literal, theory::TheoryId theory);
 396
 397   /**
 398    * Internal method to call the propagation routines and collect the
 399    * propagated literals.
 400    */
 401   void propagate(theory::Theory::Effort effort);
 402
 403   /**
 404    * Called by the output channel to request decisions "as soon as
 405    * possible."
 406    */
 407   void propagateAsDecision(TNode literal, theory::TheoryId theory);
 408
 409   /**
 410    * A variable to mark if we added any lemmas.
 411    */
 412   bool d_lemmasAdded;
 413
 414   /**
 415    * A variable to mark if the OutputChannel was "used" by any theory
 416    * since the start of the last check.  If it has been, we require
 417    * a FULL_EFFORT check before exiting and reporting SAT.
 418    *
 419    * See the documentation for the needCheck() function, below.
 420    */
 421   bool d_outputChannelUsed;
 422
 423   /** Atom requests from lemmas */
 424   AtomRequests d_atomRequests;
 425
 426   /**
 427    * Adds a new lemma, returning its status.
 428    * @param node the lemma
 429    * @param negated should the lemma be asserted negated
 430    * @param removable can the lemma be remove (restrictions apply)
 431    * @param needAtoms if not THEORY_LAST, then
 432    */
 433   theory::LemmaStatus lemma(TNode node,
 434                             ProofRule rule,
 435                             bool negated,
 436                             bool removable,
 437                             bool preprocess,
 438                             theory::TheoryId atomsTo);
 439
 440   /** Enusre that the given atoms are send to the given theory */
 441   void ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId theory);
 442
 443   RemoveITE& d_iteRemover;
 444
 445   /** sort inference module */
 446   SortInference d_sortInfer;
 447
 448   /** Time spent in theory combination */
 449   TimerStat d_combineTheoriesTime;
 450
 451   Node d_true;
 452   Node d_false;
 453
 454   /** Whether we were just interrupted (or not) */
 455   bool d_interrupted;
 456   ResourceManager* d_resourceManager;
 457
 458   /** Container for lemma input and output channels. */
 459   LemmaChannels* d_channels;
 460
 461 public:
 462
 463   /** Constructs a theory engine */
 464   TheoryEngine(context::Context* context, context::UserContext* userContext,
 465                RemoveITE& iteRemover, const LogicInfo& logic,
 466                LemmaChannels* channels);
 467
 468   /** Destroys a theory engine */
 469   ~TheoryEngine();
 470
 471   void interrupt() throw(ModalException);
 472   /**
 473    * "Spend" a resource during a search or preprocessing.
 474    */
 475   void spendResource(unsigned ammount);
 476
 477   /**
 478    * Adds a theory. Only one theory per TheoryId can be present, so if
 479    * there is another theory it will be deleted.
 480    */
 481   template <class TheoryClass>
 482   inline void addTheory(theory::TheoryId theoryId) {
 483     Assert(d_theoryTable[theoryId] == NULL && d_theoryOut[theoryId] == NULL);
 484     d_theoryOut[theoryId] = new EngineOutputChannel(this, theoryId);
 485     d_theoryTable[theoryId] =
 486         new TheoryClass(d_context, d_userContext, *d_theoryOut[theoryId],
 487                         theory::Valuation(this), d_logicInfo);
 488   }
 489
 490   inline void setPropEngine(prop::PropEngine* propEngine) {
 491     Assert(d_propEngine == NULL);
 492     d_propEngine = propEngine;
 493   }
 494
 495   inline void setDecisionEngine(DecisionEngine* decisionEngine) {
 496     Assert(d_decisionEngine == NULL);
 497     d_decisionEngine = decisionEngine;
 498   }
 499
 500   /** Called when all initialization of options/logic is done */
 501   void finishInit();
 502
 503   /**
 504    * Get a pointer to the underlying propositional engine.
 505    */
 506   inline prop::PropEngine* getPropEngine() const {
 507     return d_propEngine;
 508   }
 509
 510   /**
 511    * Get a pointer to the underlying sat context.
 512    */
 513   inline context::Context* getSatContext() const {
 514     return d_context;
 515   }
 516
 517   /**
 518    * Get a pointer to the underlying user context.
 519    */
 520   inline context::Context* getUserContext() const {
 521     return d_userContext;
 522   }
 523
 524   /**
 525    * Get a pointer to the underlying quantifiers engine.
 526    */
 527   theory::QuantifiersEngine* getQuantifiersEngine() const {
 528     return d_quantEngine;
 529   }
 530
 531 private:
 532
 533   /**
 534    * Helper for preprocess
 535    */
 536   Node ppTheoryRewrite(TNode term);
 537
 538   /**
 539    * Queue of nodes for pre-registration.
 540    */
 541   std::queue<TNode> d_preregisterQueue;
 542
 543   /**
 544    * Boolean flag denoting we are in pre-registration.
 545    */
 546   bool d_inPreregister;
 547
 548   /**
 549    * Did the theories get any new facts since the last time we called
 550    * check()
 551    */
 552   context::CDO<bool> d_factsAsserted;
 553
 554   /**
 555    * Map from equality atoms to theories that would like to be notified about them.
 556    */
 557
 558
 559   /**
 560    * Assert the formula to the given theory.
 561    * @param assertion the assertion to send (not necesserily normalized)
 562    * @param original the assertion as it was sent in from the propagating theory
 563    * @param toTheoryId the theory to assert to
 564    * @param fromTheoryId the theory that sent it
 565    */
 566   void assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 567
 568   /**
 569    * Marks a theory propagation from a theory to a theory where a
 570    * theory could be the THEORY_SAT_SOLVER for literals coming from
 571    * or being propagated to the SAT solver. If the receiving theory
 572    * already recieved the literal, the method returns false, otherwise
 573    * it returns true.
 574    *
 575    * @param assertion the normalized assertion being sent
 576    * @param originalAssertion the actual assertion that was sent
 577    * @param toTheoryId the theory that is on the receiving end
 578    * @param fromTheoryId the theory that sent the assertino
 579    * @return true if a new assertion, false if theory already got it
 580    */
 581   bool markPropagation(TNode assertion, TNode originalAssertions, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId);
 582
 583   /**
 584    * Computes the explanation by travarsing the propagation graph and
 585    * asking relevant theories to explain the propagations. Initially
 586    * the explanation vector should contain only the element (node, theory)
 587    * where the node is the one to be explained, and the theory is the
 588    * theory that sent the literal. The lemmaProofRecipe will contain a list
 589    * of the explanation steps required to produce the original node.
 590    */
 591   void getExplanation(std::vector<NodeTheoryPair>& explanationVector, LemmaProofRecipe* lemmaProofRecipe);
 592
 593 public:
 594
 595   /**
 596    * Signal the start of a new round of assertion preprocessing
 597    */
 598   void preprocessStart();
 599
 600   /**
 601    * Runs theory specific preprocessing on the non-Boolean parts of
 602    * the formula.  This is only called on input assertions, after ITEs
 603    * have been removed.
 604    */
 605   Node preprocess(TNode node);
 606
 607
 608   /**
 609    * Notify (preprocessed) assertions
 610    */
 611   void notifyPreprocessedAssertions( std::vector< Node >& assertions );
 612
 613   /**
 614    * Return whether or not we are incomplete (in the current context).
 615    */
 616   inline bool isIncomplete() const {
 617     return d_incomplete;
 618   }
 619
 620   /**
 621    * Returns true if we need another round of checking.  If this
 622    * returns true, check(FULL_EFFORT) _must_ be called by the
 623    * propositional layer before reporting SAT.
 624    *
 625    * This is especially necessary for incomplete theories that lazily
 626    * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
 627    * outputing quantifier instantiations).  In such a case, a lemma can
 628    * be asserted that is simplified away (perhaps it's already true).
 629    * However, we must maintain the invariant that, if a theory uses the
 630    * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
 631    * be performed before exit, even if no new facts are on its fact queue,
 632    * as it might decide to further instantiate some lemmas, precluding
 633    * a SAT response.
 634    */
 635   inline bool needCheck() const {
 636     return d_outputChannelUsed || d_lemmasAdded;
 637   }
 638
 639   /**
 640    * This is called at shutdown time by the SmtEngine, just before
 641    * destruction.  It is important because there are destruction
 642    * ordering issues between PropEngine and Theory.
 643    */
 644   void shutdown();
 645
 646   /**
 647    * Solve the given literal with a theory that owns it.
 648    */
 649   theory::Theory::PPAssertStatus solve(TNode literal,
 650                                     theory::SubstitutionMap& substitutionOut);
 651
 652   /**
 653    * Preregister a Theory atom with the responsible theory (or
 654    * theories).
 655    */
 656   void preRegister(TNode preprocessed);
 657
 658   /**
 659    * Assert the formula to the appropriate theory.
 660    * @param node the assertion
 661    */
 662   void assertFact(TNode node);
 663
 664   /**
 665    * Check all (currently-active) theories for conflicts.
 666    * @param effort the effort level to use
 667    */
 668   void check(theory::Theory::Effort effort);
 669
 670   /**
 671    * Run the combination framework.
 672    */
 673   void combineTheories();
 674
 675   /**
 676    * Calls ppStaticLearn() on all theories, accumulating their
 677    * combined contributions in the "learned" builder.
 678    */
 679   void ppStaticLearn(TNode in, NodeBuilder<>& learned);
 680
 681   /**
 682    * Calls presolve() on all theories and returns true
 683    * if one of the theories discovers a conflict.
 684    */
 685   bool presolve();
 686
 687    /**
 688    * Calls postsolve() on all theories.
 689    */
 690   void postsolve();
 691
 692   /**
 693    * Calls notifyRestart() on all active theories.
 694    */
 695   void notifyRestart();
 696
 697   void getPropagatedLiterals(std::vector<TNode>& literals) {
 698     for (; d_propagatedLiteralsIndex < d_propagatedLiterals.size(); d_propagatedLiteralsIndex = d_propagatedLiteralsIndex + 1) {
 699       Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals[d_propagatedLiteralsIndex] << std::endl;
 700       literals.push_back(d_propagatedLiterals[d_propagatedLiteralsIndex]);
 701     }
 702   }
 703
 704   Node getNextDecisionRequest();
 705
 706   bool properConflict(TNode conflict) const;
 707   bool properPropagation(TNode lit) const;
 708   bool properExplanation(TNode node, TNode expl) const;
 709
 710   /**
 711    * Returns an explanation of the node propagated to the SAT solver.
 712    */
 713   Node getExplanation(TNode node);
 714
 715   /**
 716    * Returns an explanation of the node propagated to the SAT solver and the theory
 717    * that propagated it.
 718    */
 719   Node getExplanationAndRecipe(TNode node, LemmaProofRecipe* proofRecipe);
 720
 721   /**
 722    * collect model info
 723    */
 724   void collectModelInfo( theory::TheoryModel* m, bool fullModel );
 725   /** post process model */
 726   void postProcessModel( theory::TheoryModel* m );
 727
 728   /**
 729    * Get the current model
 730    */
 731   theory::TheoryModel* getModel();
 732
 733   /**
 734    * Get the model builder
 735    */
 736   theory::TheoryEngineModelBuilder* getModelBuilder() { return d_curr_model_builder; }
 737
 738   /**
 739    * Get the theory associated to a given Node.
 740    *
 741    * @returns the theory, or NULL if the TNode is
 742    * of built-in type.
 743    */
 744   inline theory::Theory* theoryOf(TNode node) const {
 745     return d_theoryTable[theory::Theory::theoryOf(node)];
 746   }
 747
 748   /**
 749    * Get the theory associated to a the given theory id.
 750    *
 751    * @returns the theory
 752    */
 753   inline theory::Theory* theoryOf(theory::TheoryId theoryId) const {
 754     return d_theoryTable[theoryId];
 755   }
 756
 757   inline bool isTheoryEnabled(theory::TheoryId theoryId) const {
 758     return d_logicInfo.isTheoryEnabled(theoryId);
 759   }
 760
 761   /**
 762    * Returns the equality status of the two terms, from the theory
 763    * that owns the domain type.  The types of a and b must be the same.
 764    */
 765   theory::EqualityStatus getEqualityStatus(TNode a, TNode b);
 766
 767   /**
 768    * Returns the value that a theory that owns the type of var currently
 769    * has (or null if none);
 770    */
 771   Node getModelValue(TNode var);
 772
 773   /**
 774    * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
 775    */
 776   Node ensureLiteral(TNode n);
 777
 778   /**
 779    * Print all instantiations made by the quantifiers module.
 780    */
 781   void printInstantiations( std::ostream& out );
 782
 783   /**
 784    * Print solution for synthesis conjectures found by ce_guided_instantiation module
 785    */
 786   void printSynthSolution( std::ostream& out );
 787
 788   /**
 789    * Get instantiations
 790    */
 791   void getInstantiations( std::map< Node, std::vector< Node > >& insts );
 792
 793   /**
 794    * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
 795    *   Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
 796    */
 797   Node getInstantiatedConjunction( Node q );
 798
 799   /**
 800    * Forwards an entailment check according to the given theoryOfMode.
 801    * See theory.h for documentation on entailmentCheck().
 802    */
 803   std::pair<bool, Node> entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL);
 804
 805 private:
 806
 807   /** Default visitor for pre-registration */
 808   PreRegisterVisitor d_preRegistrationVisitor;
 809
 810   /** Visitor for collecting shared terms */
 811   SharedTermsVisitor d_sharedTermsVisitor;
 812
 813   /** Dump the assertions to the dump */
 814   void dumpAssertions(const char* tag);
 815
 816   /**
 817    * A collection of ite preprocessing passes.
 818    */
 819   theory::ITEUtilities* d_iteUtilities;
 820
 821
 822   /** For preprocessing pass simplifying unconstrained expressions */
 823   UnconstrainedSimplifier* d_unconstrainedSimp;
 824
 825   /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
 826   theory::bv::BvToBoolPreprocessor d_bvToBoolPreprocessor;
 827 public:
 828   void staticInitializeBVOptions(const std::vector<Node>& assertions);
 829   void ppBvToBool(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 830   bool ppBvAbstraction(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
 831   void mkAckermanizationAsssertions(std::vector<Node>& assertions);
 832
 833   Node ppSimpITE(TNode assertion);
 834   /** Returns false if an assertion simplified to false. */
 835   bool donePPSimpITE(std::vector<Node>& assertions);
 836
 837   void ppUnconstrainedSimp(std::vector<Node>& assertions);
 838
 839   SharedTermsDatabase* getSharedTermsDatabase() { return &d_sharedTerms; }
 840
 841   theory::eq::EqualityEngine* getMasterEqualityEngine() { return d_masterEqualityEngine; }
 842
 843   RemoveITE* getIteRemover() { return &d_iteRemover; }
 844
 845   SortInference* getSortInference() { return &d_sortInfer; }
 846
 847   /** Prints the assertions to the debug stream */
 848   void printAssertions(const char* tag);
 849
 850   /** Theory alternative is in use. */
 851   bool useTheoryAlternative(const std::string& name);
 852
 853   /** Enables using a theory alternative by name. */
 854   void enableTheoryAlternative(const std::string& name);
 855
 856 private:
 857   std::set< std::string > d_theoryAlternatives;
 858
 859   std::map< std::string, std::vector< theory::Theory* > > d_attr_handle;
 860 public:
 861
 862   /**
 863    * Set user attribute.
 864    * This function is called when an attribute is set by a user.  In SMT-LIBv2 this is done
 865    * via the syntax (! n :attr)
 866    */
 867   void setUserAttribute(const std::string& attr, Node n, std::vector<Node>& node_values, std::string str_value);
 868
 869   /**
 870    * Handle user attribute.
 871    * Associates theory t with the attribute attr.  Theory t will be
 872    * notified whenever an attribute of name attr is set.
 873    */
 874   void handleUserAttribute(const char* attr, theory::Theory* t);
 875
 876   /**
 877    * Check that the theory assertions are satisfied in the model.
 878    * This function is called from the smt engine's checkModel routine.
 879    */
 880   void checkTheoryAssertionsWithModel();
 881
 882 private:
 883   IntStat d_arithSubstitutionsAdded;
 884
 885 };/* class TheoryEngine */
 886
 887 }/* CVC4 namespace */
 888
 889 #endif /* __CVC4__THEORY_ENGINE_H */