Head

GCC Code Coverage Report
Directory:	.		Exec	Total	Coverage
File:	src/theory/theory_engine.cpp	Lines:	715	851	84.0 %
Date:	2021-11-05	Branches:	1802	4362	41.3 %

/******************************************************************************
 * Top contributors (to current version):
 *   Andrew Reynolds, Dejan Jovanovic, Morgan Deters
 *
 * This file is part of the cvc5 project.
 *
 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
 * in the top-level source directory and their institutional affiliations.
 * All rights reserved.  See the file COPYING in the top-level source
 * directory for licensing information.
 * ****************************************************************************
 *
 * The theory engine.
 */

#include "theory/theory_engine.h"

#include <sstream>

#include "base/map_util.h"
#include "decision/decision_engine.h"
#include "expr/attribute.h"
#include "expr/node_builder.h"
#include "expr/node_visitor.h"
#include "options/quantifiers_options.h"
#include "options/smt_options.h"
#include "options/theory_options.h"
#include "printer/printer.h"
#include "proof/lazy_proof.h"
#include "proof/proof_checker.h"
#include "proof/proof_ensure_closed.h"
#include "prop/prop_engine.h"
#include "smt/env.h"
#include "smt/logic_exception.h"
#include "theory/combination_care_graph.h"
#include "theory/decision_manager.h"
#include "theory/quantifiers/first_order_model.h"
#include "theory/quantifiers_engine.h"
#include "theory/relevance_manager.h"
#include "theory/rewriter.h"
#include "theory/shared_solver.h"
#include "theory/theory.h"
#include "theory/theory_engine_proof_generator.h"
#include "theory/theory_id.h"
#include "theory/theory_model.h"
#include "theory/theory_traits.h"
#include "theory/uf/equality_engine.h"
#include "util/resource_manager.h"

using namespace std;

using namespace cvc5::theory;

namespace cvc5 {

/* -------------------------------------------------------------------------- */

namespace theory {

/**
 * IMPORTANT: The order of the theories is important. For example, strings
 *            depends on arith, quantifiers needs to come as the very last.
 *            Do not change this order.
 */

#define CVC5_FOR_EACH_THEORY                                     \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_BUILTIN)   \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_BOOL)      \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_UF)        \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_ARITH)     \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_BV)        \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_FP)        \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_ARRAYS)    \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_DATATYPES) \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_SEP)       \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_SETS)      \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_BAGS)      \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_STRINGS)   \
  CVC5_FOR_EACH_THEORY_STATEMENT(cvc5::theory::THEORY_QUANTIFIERS)

}  // namespace theory

/* -------------------------------------------------------------------------- */

inline void flattenAnd(Node n, std::vector<TNode>& out){
  Assert(n.getKind() == kind::AND);
  for(Node::iterator i=n.begin(), i_end=n.end(); i != i_end; ++i){
    Node curr = *i;
    if(curr.getKind() == kind::AND){
      flattenAnd(curr, out);
    }else{
      out.push_back(curr);
    }
  }
}

inline Node flattenAnd(Node n){
  std::vector<TNode> out;
  flattenAnd(n, out);
  return NodeManager::currentNM()->mkNode(kind::AND, out);
}

/**
 * Compute the string for a given theory id. In this module, we use
 * THEORY_SAT_SOLVER as an id, which is not a normal id but maps to
 * THEORY_LAST. Thus, we need our own string conversion here.
 *
 * @param id The theory id
 * @return The string corresponding to the theory id
 */
std::string getTheoryString(theory::TheoryId id)
{
  if (id == theory::THEORY_SAT_SOLVER)
  {
    return "THEORY_SAT_SOLVER";
  }
  else
  {
    std::stringstream ss;
    ss << id;
    return ss.str();
  }
}

void TheoryEngine::finishInit()
{
  Trace("theory") << "Begin TheoryEngine::finishInit" << std::endl;
  // NOTE: This seems to be required since
  // theory::TheoryTraits<THEORY>::isParametric cannot be accessed without
  // using the CVC5_FOR_EACH_THEORY_STATEMENT macro. -AJR
  std::vector<theory::Theory*> paraTheories;
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)   \
  if (theory::TheoryTraits<THEORY>::isParametric \
      && d_logicInfo.isTheoryEnabled(THEORY))    \
  {                                              \
    paraTheories.push_back(theoryOf(THEORY));    \
  }
  // Collect the parametric theories, which are given to the theory combination
  // manager below
  CVC5_FOR_EACH_THEORY;

  // Initialize the theory combination architecture
  if (options().theory.tcMode == options::TcMode::CARE_GRAPH)
  {
    d_tc.reset(new CombinationCareGraph(d_env, *this, paraTheories));
  }
  else
  {
    Unimplemented() << "TheoryEngine::finishInit: theory combination mode "
                    << options().theory.tcMode << " not supported";
  }
  // create the relevance filter if any option requires it
  if (options().theory.relevanceFilter || options().smt.produceDifficulty)
  {
    d_relManager.reset(new RelevanceManager(userContext(), Valuation(this)));
  }

  // initialize the quantifiers engine
  if (d_logicInfo.isQuantified())
  {
    // get the quantifiers engine, which is initialized by the quantifiers
    // theory
    d_quantEngine = d_theoryTable[THEORY_QUANTIFIERS]->getQuantifiersEngine();
    Assert(d_quantEngine != nullptr);
  }
  // finish initializing the quantifiers engine, which must come before
  // initializing theory combination, since quantifiers engine may have a
  // special model builder object
  if (d_logicInfo.isQuantified())
  {
    d_quantEngine->finishInit(this);
  }
  // initialize the theory combination manager, which decides and allocates the
  // equality engines to use for all theories.
  d_tc->finishInit();
  // get pointer to the shared solver
  d_sharedSolver = d_tc->getSharedSolver();

  // finish initializing the theories by linking them with the appropriate
  // utilities and then calling their finishInit method.
  for(TheoryId theoryId = theory::THEORY_FIRST; theoryId != theory::THEORY_LAST; ++ theoryId) {
    Theory* t = d_theoryTable[theoryId];
    if (t == nullptr)
    {
      continue;
    }
    // setup the pointers to the utilities
    const EeTheoryInfo* eeti = d_tc->getEeTheoryInfo(theoryId);
    Assert(eeti != nullptr);
    // the theory's official equality engine is the one specified by the
    // equality engine manager
    t->setEqualityEngine(eeti->d_usedEe);
    // set the quantifiers engine
    t->setQuantifiersEngine(d_quantEngine);
    // set the decision manager for the theory
    t->setDecisionManager(d_decManager.get());
    // finish initializing the theory
    t->finishInit();
  }
  Trace("theory") << "End TheoryEngine::finishInit" << std::endl;
}

TheoryEngine::TheoryEngine(Env& env)
    : EnvObj(env),
      d_propEngine(nullptr),
      d_logicInfo(env.getLogicInfo()),
      d_pnm(d_env.isTheoryProofProducing() ? d_env.getProofNodeManager()
                                           : nullptr),
      d_lazyProof(
          d_pnm != nullptr ? new LazyCDProof(
              d_pnm, nullptr, userContext(), "TheoryEngine::LazyCDProof")
                           : nullptr),
      d_tepg(new TheoryEngineProofGenerator(d_pnm, userContext())),
      d_tc(nullptr),
      d_sharedSolver(nullptr),
      d_quantEngine(nullptr),
      d_decManager(new DecisionManager(userContext())),
      d_relManager(nullptr),
      d_inConflict(context(), false),
      d_inSatMode(false),
      d_hasShutDown(false),
      d_incomplete(context(), false),
      d_incompleteTheory(context(), THEORY_BUILTIN),
      d_incompleteId(context(), IncompleteId::UNKNOWN),
      d_propagationMap(context()),
      d_propagationMapTimestamp(context(), 0),
      d_propagatedLiterals(context()),
      d_propagatedLiteralsIndex(context(), 0),
      d_atomRequests(context()),
      d_combineTheoriesTime(statisticsRegistry().registerTimer(
          "TheoryEngine::combineTheoriesTime")),
      d_true(),
      d_false(),
      d_interrupted(false),
      d_inPreregister(false),
      d_factsAsserted(context(), false)
{
  for(TheoryId theoryId = theory::THEORY_FIRST; theoryId != theory::THEORY_LAST;
      ++ theoryId)
  {
    d_theoryTable[theoryId] = NULL;
    d_theoryOut[theoryId] = NULL;
  }

  if (options().smt.sortInference)
  {
    d_sortInfer.reset(new SortInference(env));
  }

  d_true = NodeManager::currentNM()->mkConst<bool>(true);
  d_false = NodeManager::currentNM()->mkConst<bool>(false);
}

TheoryEngine::~TheoryEngine() {
  Assert(d_hasShutDown);

  for(TheoryId theoryId = theory::THEORY_FIRST; theoryId != theory::THEORY_LAST; ++ theoryId) {
    if(d_theoryTable[theoryId] != NULL) {
      delete d_theoryTable[theoryId];
      delete d_theoryOut[theoryId];
    }
  }
}

void TheoryEngine::interrupt() { d_interrupted = true; }
void TheoryEngine::preRegister(TNode preprocessed) {
  Debug("theory") << "TheoryEngine::preRegister( " << preprocessed << ")"
                  << std::endl;
  d_preregisterQueue.push(preprocessed);

  if (!d_inPreregister) {
    // We're in pre-register
    d_inPreregister = true;

    // Process the pre-registration queue
    while (!d_preregisterQueue.empty()) {
      // Get the next atom to pre-register
      preprocessed = d_preregisterQueue.front();
      d_preregisterQueue.pop();

      // the atom should not have free variables
      Debug("theory") << "TheoryEngine::preRegister: " << preprocessed
                      << std::endl;
      if (Configuration::isAssertionBuild())
      {
        std::unordered_set<Node> fvs;
        expr::getFreeVariables(preprocessed, fvs);
        if (!fvs.empty())
        {
          Unhandled() << "Preregistered term with free variable: "
                      << preprocessed << ", fv=" << *fvs.begin();
        }
      }
      // should not have witness
      Assert(!expr::hasSubtermKind(kind::WITNESS, preprocessed));

      // pre-register with the shared solver, which handles
      // calling prepregister on individual theories, adding shared terms,
      // and setting up equalities to propagate in the shared term database.
      Assert(d_sharedSolver != nullptr);
      d_sharedSolver->preRegister(preprocessed);
    }

    // Leaving pre-register
    d_inPreregister = false;
  }
}

void TheoryEngine::printAssertions(const char* tag) {
  if (Trace.isOn(tag)) {

    for (TheoryId theoryId = THEORY_FIRST; theoryId < THEORY_LAST; ++theoryId) {
      Theory* theory = d_theoryTable[theoryId];
      if (theory && d_logicInfo.isTheoryEnabled(theoryId)) {
        Trace(tag) << "--------------------------------------------" << endl;
        Trace(tag) << "Assertions of " << theory->getId() << ": " << endl;
        {
          context::CDList<Assertion>::const_iterator it = theory->facts_begin(),
                                                     it_end =
                                                         theory->facts_end();
          for (unsigned i = 0; it != it_end; ++it, ++i)
          {
            if ((*it).d_isPreregistered)
            {
              Trace(tag) << "[" << i << "]: ";
            }
            else
            {
              Trace(tag) << "(" << i << "): ";
            }
            Trace(tag) << (*it).d_assertion << endl;
          }
        }

        if (d_logicInfo.isSharingEnabled()) {
          Trace(tag) << "Shared terms of " << theory->getId() << ": " << endl;
          context::CDList<TNode>::const_iterator it = theory->shared_terms_begin(), it_end = theory->shared_terms_end();
          for (unsigned i = 0; it != it_end; ++ it, ++i) {
              Trace(tag) << "[" << i << "]: " << (*it) << endl;
          }
        }
      }
    }
  }
}

/**
 * Check all (currently-active) theories for conflicts.
 * @param effort the effort level to use
 */
void TheoryEngine::check(Theory::Effort effort) {
  // spendResource();

  // Reset the interrupt flag
  d_interrupted = false;

#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)                      \
  if (theory::TheoryTraits<THEORY>::hasCheck                        \
      && d_logicInfo.isTheoryEnabled(THEORY))                       \
  {                                                                 \
    theoryOf(THEORY)->check(effort);                                \
    if (d_inConflict)                                               \
    {                                                               \
      Debug("conflict") << THEORY << " in conflict. " << std::endl; \
      break;                                                        \
    }                                                               \
  }

  // Do the checking
  try {

    // Mark the output channel unused (if this is FULL_EFFORT, and nothing
    // is done by the theories, no additional check will be needed)
    d_outputChannelUsed = false;

    // Mark the lemmas flag (no lemmas added)
    d_lemmasAdded = false;

    Debug("theory") << "TheoryEngine::check(" << effort << "): d_factsAsserted = " << (d_factsAsserted ? "true" : "false") << endl;

    // If in full effort, we have a fake new assertion just to jumpstart the checking
    if (Theory::fullEffort(effort)) {
      d_factsAsserted = true;
      // Reset round for the relevance manager, which notice only sets a flag
      // to indicate that its information must be recomputed.
      if (d_relManager != nullptr)
      {
        d_relManager->resetRound();
      }
      d_tc->resetRound();
    }

    // Check until done
    while (d_factsAsserted && !d_inConflict && !d_lemmasAdded) {

      Debug("theory") << "TheoryEngine::check(" << effort << "): running check" << endl;

      Trace("theory::assertions") << endl;
      if (Trace.isOn("theory::assertions")) {
        printAssertions("theory::assertions");
      }

      if(Theory::fullEffort(effort)) {
        Trace("theory::assertions::fulleffort") << endl;
        if (Trace.isOn("theory::assertions::fulleffort")) {
          printAssertions("theory::assertions::fulleffort");
        }
      }

      // Note that we've discharged all the facts
      d_factsAsserted = false;

      // Do the checking
      CVC5_FOR_EACH_THEORY;

      Debug("theory") << "TheoryEngine::check(" << effort << "): running propagation after the initial check" << endl;

      // We are still satisfiable, propagate as much as possible
      propagate(effort);

      // We do combination if all has been processed and we are in fullcheck
      if (Theory::fullEffort(effort) && d_logicInfo.isSharingEnabled()
          && !d_factsAsserted && !needCheck() && !d_inConflict)
      {
        // Do the combination
        Debug("theory") << "TheoryEngine::check(" << effort << "): running combination" << endl;
        {
          TimerStat::CodeTimer combineTheoriesTimer(d_combineTheoriesTime);
          d_tc->combineTheories();
        }
        if(d_logicInfo.isQuantified()){
          d_quantEngine->notifyCombineTheories();
        }
      }
    }

    // Must consult quantifiers theory for last call to ensure sat, or otherwise add a lemma
    if( Theory::fullEffort(effort) && ! d_inConflict && ! needCheck() ) {
      Trace("theory::assertions-model") << endl;
      if (Trace.isOn("theory::assertions-model")) {
        printAssertions("theory::assertions-model");
      }
      // reset the model in the combination engine
      d_tc->resetModel();
      //checks for theories requiring the model go at last call
      for (TheoryId theoryId = THEORY_FIRST; theoryId < THEORY_LAST; ++theoryId) {
        if( theoryId!=THEORY_QUANTIFIERS ){
          Theory* theory = d_theoryTable[theoryId];
          if (theory && d_logicInfo.isTheoryEnabled(theoryId)) {
            if( theory->needsCheckLastEffort() ){
              if (!d_tc->buildModel())
              {
                break;
              }
              theory->check(Theory::EFFORT_LAST_CALL);
            }
          }
        }
      }
      if (!d_inConflict)
      {
        if(d_logicInfo.isQuantified()) {
          // quantifiers engine must check at last call effort
          d_quantEngine->check(Theory::EFFORT_LAST_CALL);
        }
      }
      // notify the relevant manager
      if (d_relManager != nullptr)
      {
        d_relManager->notifyCandidateModel(getModel());
      }
      if (!d_inConflict && !needCheck())
      {
        // We only mark that we are in "SAT mode". We build the model later only
        // if the user asks for it via getBuiltModel.
        d_inSatMode = true;
      }
    }

    Debug("theory") << "TheoryEngine::check(" << effort << "): done, we are " << (d_inConflict ? "unsat" : "sat") << (d_lemmasAdded ? " with new lemmas" : " with no new lemmas");
    Debug("theory") << ", need check = " << (needCheck() ? "YES" : "NO") << endl;

    if( Theory::fullEffort(effort) && !d_inConflict && !needCheck()) {
      // Do post-processing of model from the theories (e.g. used for THEORY_SEP
      // to construct heap model)
      d_tc->postProcessModel(d_incomplete.get());
    }
  } catch(const theory::Interrupted&) {
    Trace("theory") << "TheoryEngine::check() => interrupted" << endl;
  }
}

void TheoryEngine::propagate(Theory::Effort effort)
{
  // Reset the interrupt flag
  d_interrupted = false;

  // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)   \
  if (theory::TheoryTraits<THEORY>::hasPropagate \
      && d_logicInfo.isTheoryEnabled(THEORY))    \
  {                                              \
    theoryOf(THEORY)->propagate(effort);         \
  }

  // Reset the interrupt flag
  d_interrupted = false;

  // Propagate for each theory using the statement above
  CVC5_FOR_EACH_THEORY;
}

Node TheoryEngine::getNextDecisionRequest()
{
  return d_decManager->getNextDecisionRequest();
}

bool TheoryEngine::properConflict(TNode conflict) const {
  bool value;
  if (conflict.getKind() == kind::AND) {
    for (unsigned i = 0; i < conflict.getNumChildren(); ++ i) {
      if (! getPropEngine()->hasValue(conflict[i], value)) {
        Debug("properConflict") << "Bad conflict is due to unassigned atom: "
                                << conflict[i] << endl;
        return false;
      }
      if (! value) {
        Debug("properConflict") << "Bad conflict is due to false atom: "
                                << conflict[i] << endl;
        return false;
      }
      if (conflict[i] != Rewriter::rewrite(conflict[i])) {
        Debug("properConflict") << "Bad conflict is due to atom not in normal form: "
                                << conflict[i] << " vs " << Rewriter::rewrite(conflict[i]) << endl;
        return false;
      }
    }
  } else {
    if (! getPropEngine()->hasValue(conflict, value)) {
      Debug("properConflict") << "Bad conflict is due to unassigned atom: "
                              << conflict << endl;
      return false;
    }
    if(! value) {
      Debug("properConflict") << "Bad conflict is due to false atom: "
                              << conflict << endl;
      return false;
    }
    if (conflict != Rewriter::rewrite(conflict)) {
      Debug("properConflict") << "Bad conflict is due to atom not in normal form: "
                              << conflict << " vs " << Rewriter::rewrite(conflict) << endl;
      return false;
    }
  }
  return true;
}

TheoryModel* TheoryEngine::getModel()
{
  Assert(d_tc != nullptr);
  TheoryModel* m = d_tc->getModel();
  Assert(m != nullptr);
  return m;
}

TheoryModel* TheoryEngine::getBuiltModel()
{
  Assert(d_tc != nullptr);
  // If this method was called, we should be in SAT mode, and produceModels
  // should be true.
  AlwaysAssert(options().smt.produceModels);
  if (!d_inSatMode)
  {
    // not available, perhaps due to interuption.
    return nullptr;
  }
  // must build model at this point
  if (!d_tc->buildModel())
  {
    return nullptr;
  }
  return d_tc->getModel();
}

bool TheoryEngine::buildModel()
{
  Assert(d_tc != nullptr);
  return d_tc->buildModel();
}

bool TheoryEngine::presolve() {
  // Reset the interrupt flag
  d_interrupted = false;

  // Reset the decision manager. This clears its decision strategies that are
  // no longer valid in this user context.
  d_decManager->presolve();

  try {
    // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)   \
  if (theory::TheoryTraits<THEORY>::hasPresolve) \
  {                                              \
    theoryOf(THEORY)->presolve();                \
    if (d_inConflict)                            \
    {                                            \
      return true;                               \
    }                                            \
  }

    // Presolve for each theory using the statement above
    CVC5_FOR_EACH_THEORY;
  } catch(const theory::Interrupted&) {
    Trace("theory") << "TheoryEngine::presolve() => interrupted" << endl;
  }
  // return whether we have a conflict
  return false;
}/* TheoryEngine::presolve() */

void TheoryEngine::postsolve() {
  // no longer in SAT mode
  d_inSatMode = false;
  // Reset the interrupt flag
  d_interrupted = false;
  CVC5_UNUSED bool wasInConflict = d_inConflict;

  try {
    // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)    \
  if (theory::TheoryTraits<THEORY>::hasPostsolve) \
  {                                               \
    theoryOf(THEORY)->postsolve();                \
    Assert(!d_inConflict || wasInConflict)        \
        << "conflict raised during postsolve()";  \
  }

    // Postsolve for each theory using the statement above
    CVC5_FOR_EACH_THEORY;
  } catch(const theory::Interrupted&) {
    Trace("theory") << "TheoryEngine::postsolve() => interrupted" << endl;
  }
}/* TheoryEngine::postsolve() */


void TheoryEngine::notifyRestart() {
  // Reset the interrupt flag
  d_interrupted = false;

  // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)       \
  if (theory::TheoryTraits<THEORY>::hasNotifyRestart \
      && d_logicInfo.isTheoryEnabled(THEORY))        \
  {                                                  \
    theoryOf(THEORY)->notifyRestart();               \
  }

  // notify each theory using the statement above
  CVC5_FOR_EACH_THEORY;
}

void TheoryEngine::ppStaticLearn(TNode in, NodeBuilder& learned)
{
  // Reset the interrupt flag
  d_interrupted = false;

  // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY)        \
  if (theory::TheoryTraits<THEORY>::hasPpStaticLearn) \
  {                                                   \
    theoryOf(THEORY)->ppStaticLearn(in, learned);     \
  }

  // static learning for each theory using the statement above
  CVC5_FOR_EACH_THEORY;
}

bool TheoryEngine::isRelevant(Node lit) const
{
  if (d_relManager != nullptr)
  {
    return d_relManager->isRelevant(lit);
  }
  // otherwise must assume its relevant
  return true;
}

void TheoryEngine::shutdown() {
  // Set this first; if a Theory shutdown() throws an exception,
  // at least the destruction of the TheoryEngine won't confound
  // matters.
  d_hasShutDown = true;

  // Shutdown all the theories
  for(TheoryId theoryId = theory::THEORY_FIRST; theoryId < theory::THEORY_LAST; ++theoryId) {
    if(d_theoryTable[theoryId]) {
      theoryOf(theoryId)->shutdown();
    }
  }
}

theory::Theory::PPAssertStatus TheoryEngine::solve(
    TrustNode tliteral, TrustSubstitutionMap& substitutionOut)
{
  // Reset the interrupt flag
  d_interrupted = false;

  TNode literal = tliteral.getNode();
  TNode atom = literal.getKind() == kind::NOT ? literal[0] : literal;
  Trace("theory::solve") << "TheoryEngine::solve(" << literal << "): solving with " << theoryOf(atom)->getId() << endl;

  if(! d_logicInfo.isTheoryEnabled(Theory::theoryOf(atom)) &&
     Theory::theoryOf(atom) != THEORY_SAT_SOLVER) {
    stringstream ss;
    ss << "The logic was specified as " << d_logicInfo.getLogicString()
       << ", which doesn't include " << Theory::theoryOf(atom)
       << ", but got a preprocessing-time fact for that theory." << endl
       << "The fact:" << endl
       << literal;
    throw LogicException(ss.str());
  }

  Theory::PPAssertStatus solveStatus =
      theoryOf(atom)->ppAssert(tliteral, substitutionOut);
  Trace("theory::solve") << "TheoryEngine::solve(" << literal << ") => " << solveStatus << endl;
  return solveStatus;
}

TrustNode TheoryEngine::ppRewriteEquality(TNode eq)
{
  Assert(eq.getKind() == kind::EQUAL);
  std::vector<SkolemLemma> lems;
  TrustNode trn = theoryOf(eq)->ppRewrite(eq, lems);
  // should never introduce a skolem to eliminate an equality
  Assert(lems.empty());
  return trn;
}

void TheoryEngine::notifyPreprocessedAssertions(
    const std::vector<Node>& assertions) {
  // call all the theories
  for (TheoryId theoryId = theory::THEORY_FIRST; theoryId < theory::THEORY_LAST;
       ++theoryId) {
    if (d_theoryTable[theoryId]) {
      theoryOf(theoryId)->ppNotifyAssertions(assertions);
    }
  }
  if (d_relManager != nullptr)
  {
    d_relManager->notifyPreprocessedAssertions(assertions);
  }
}

bool TheoryEngine::markPropagation(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId) {
  // What and where we are asserting
  NodeTheoryPair toAssert(assertion, toTheoryId, d_propagationMapTimestamp);
  // What and where it came from
  NodeTheoryPair toExplain(originalAssertion, fromTheoryId, d_propagationMapTimestamp);

  // See if the theory already got this literal
  PropagationMap::const_iterator find = d_propagationMap.find(toAssert);
  if (find != d_propagationMap.end()) {
    // The theory already knows this
    Trace("theory::assertToTheory") << "TheoryEngine::markPropagation(): already there" << endl;
    return false;
  }

  Trace("theory::assertToTheory") << "TheoryEngine::markPropagation(): marking [" << d_propagationMapTimestamp << "] " << assertion << ", " << toTheoryId << " from " << originalAssertion << ", " << fromTheoryId << endl;

  // Mark the propagation
  d_propagationMap[toAssert] = toExplain;
  d_propagationMapTimestamp = d_propagationMapTimestamp + 1;

  return true;
}


void TheoryEngine::assertToTheory(TNode assertion, TNode originalAssertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId) {
  Trace("theory::assertToTheory") << "TheoryEngine::assertToTheory(" << assertion << ", " << originalAssertion << "," << toTheoryId << ", " << fromTheoryId << ")" << endl;

  Assert(toTheoryId != fromTheoryId);
  if(toTheoryId != THEORY_SAT_SOLVER &&
     ! d_logicInfo.isTheoryEnabled(toTheoryId)) {
    stringstream ss;
    ss << "The logic was specified as " << d_logicInfo.getLogicString()
       << ", which doesn't include " << toTheoryId
       << ", but got an asserted fact to that theory." << endl
       << "The fact:" << endl
       << assertion;
    throw LogicException(ss.str());
  }

  if (d_inConflict) {
    return;
  }

  // If sharing is disabled, things are easy
  if (!d_logicInfo.isSharingEnabled()) {
    Assert(assertion == originalAssertion);
    if (fromTheoryId == THEORY_SAT_SOLVER) {
      // Send to the apropriate theory
      theory::Theory* toTheory = theoryOf(toTheoryId);
      // We assert it, and we know it's preregistereed
      toTheory->assertFact(assertion, true);
      // Mark that we have more information
      d_factsAsserted = true;
    } else {
      Assert(toTheoryId == THEORY_SAT_SOLVER);
      // Check for propositional conflict
      bool value;
      if (d_propEngine->hasValue(assertion, value)) {
        if (!value) {
          Trace("theory::propagate") << "TheoryEngine::assertToTheory(" << assertion << ", " << toTheoryId << ", " << fromTheoryId << "): conflict (no sharing)" << endl;
          Trace("dtview::conflict")
              << ":THEORY-CONFLICT: " << assertion << std::endl;
          markInConflict();
        } else {
          return;
        }
      }
      d_propagatedLiterals.push_back(assertion);
    }
    return;
  }

  // determine the actual theory that will process/explain the fact, which is
  // THEORY_BUILTIN if the theory uses the central equality engine
  TheoryId toTheoryIdProp = (Theory::expUsingCentralEqualityEngine(toTheoryId))
                                ? THEORY_BUILTIN
                                : toTheoryId;
  // If sending to the shared solver, it's also simple
  if (toTheoryId == THEORY_BUILTIN) {
    if (markPropagation(
            assertion, originalAssertion, toTheoryIdProp, fromTheoryId))
    {
      // assert to the shared solver
      bool polarity = assertion.getKind() != kind::NOT;
      TNode atom = polarity ? assertion : assertion[0];
      d_sharedSolver->assertShared(atom, polarity, assertion);
    }
    return;
  }

  // Things from the SAT solver are already normalized, so they go
  // directly to the apropriate theory
  if (fromTheoryId == THEORY_SAT_SOLVER) {
    // We know that this is normalized, so just send it off to the theory
    if (markPropagation(
            assertion, originalAssertion, toTheoryIdProp, fromTheoryId))
    {
      // Is it preregistered
      bool preregistered = d_propEngine->isSatLiteral(assertion) && Theory::theoryOf(assertion) == toTheoryId;
      // We assert it
      theoryOf(toTheoryId)->assertFact(assertion, preregistered);
      // Mark that we have more information
      d_factsAsserted = true;
    }
    return;
  }

  // Propagations to the SAT solver are just enqueued for pickup by
  // the SAT solver later
  if (toTheoryId == THEORY_SAT_SOLVER) {
    Assert(toTheoryIdProp == toTheoryId);
    if (markPropagation(assertion, originalAssertion, toTheoryId, fromTheoryId)) {
      // Enqueue for propagation to the SAT solver
      d_propagatedLiterals.push_back(assertion);
      // Check for propositional conflicts
      bool value;
      if (d_propEngine->hasValue(assertion, value) && !value) {
        Trace("theory::propagate")
            << "TheoryEngine::assertToTheory(" << assertion << ", "
            << toTheoryId << ", " << fromTheoryId << "): conflict (sharing)"
            << endl;
        Trace("dtview::conflict")
            << ":THEORY-CONFLICT: " << assertion << std::endl;
        markInConflict();
      }
    }
    return;
  }

  Assert(assertion.getKind() == kind::EQUAL
         || (assertion.getKind() == kind::NOT
             && assertion[0].getKind() == kind::EQUAL));

  // Normalize
  Node normalizedLiteral = Rewriter::rewrite(assertion);

  // See if it rewrites false directly -> conflict
  if (normalizedLiteral.isConst()) {
    if (!normalizedLiteral.getConst<bool>()) {
      // Mark the propagation for explanations
      if (markPropagation(normalizedLiteral,
                          originalAssertion,
                          toTheoryIdProp,
                          fromTheoryId))
      {
        // special case, trust node has no proof generator
        TrustNode trnn = TrustNode::mkTrustConflict(normalizedLiteral);
        // Get the explanation (conflict will figure out where it came from)
        conflict(trnn, toTheoryId);
      } else {
        Unreachable();
      }
      return;
    }
  }

  // Try and assert (note that we assert the non-normalized one)
  if (markPropagation(
          assertion, originalAssertion, toTheoryIdProp, fromTheoryId))
  {
    // Check if has been pre-registered with the theory
    bool preregistered = d_propEngine->isSatLiteral(assertion) && Theory::theoryOf(assertion) == toTheoryId;
    // Assert away
    theoryOf(toTheoryId)->assertFact(assertion, preregistered);
    d_factsAsserted = true;
  }

  return;
}

void TheoryEngine::assertFact(TNode literal)
{
  Trace("theory") << "TheoryEngine::assertFact(" << literal << ")" << endl;

  // spendResource();

  // If we're in conflict, nothing to do
  if (d_inConflict) {
    return;
  }

  // Get the atom
  bool polarity = literal.getKind() != kind::NOT;
  TNode atom = polarity ? literal : literal[0];

  if (d_logicInfo.isSharingEnabled()) {
    // If any shared terms, it's time to do sharing work
    d_sharedSolver->preNotifySharedFact(atom);

    // If it's an equality, assert it to the shared term manager, even though the terms are not
    // yet shared. As the terms become shared later, the shared terms manager will then add them
    // to the assert the equality to the interested theories
    if (atom.getKind() == kind::EQUAL) {
      // Assert it to the the owning theory
      assertToTheory(literal, literal, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
      // Shared terms manager will assert to interested theories directly, as
      // the terms become shared
      assertToTheory(literal, literal, /* to */ THEORY_BUILTIN, /* from */ THEORY_SAT_SOLVER);

      // Now, let's check for any atom triggers from lemmas
      AtomRequests::atom_iterator it = d_atomRequests.getAtomIterator(atom);
      while (!it.done()) {
        const AtomRequests::Request& request = it.get();
        Node toAssert =
            polarity ? (Node)request.d_atom : request.d_atom.notNode();
        Debug("theory::atoms") << "TheoryEngine::assertFact(" << literal
                               << "): sending requested " << toAssert << endl;
        assertToTheory(
            toAssert, literal, request.d_toTheory, THEORY_SAT_SOLVER);
        it.next();
      }

    } else {
      // Not an equality, just assert to the appropriate theory
      assertToTheory(literal, literal, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
    }
  } else {
    // Assert the fact to the appropriate theory directly
    assertToTheory(literal, literal, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
  }
}

bool TheoryEngine::propagate(TNode literal, theory::TheoryId theory) {
  Debug("theory::propagate")
      << "TheoryEngine::propagate(" << literal << ", " << theory << ")" << endl;

  Trace("dtview::prop") << std::string(context()->getLevel(), ' ')
                        << ":THEORY-PROP: " << literal << endl;

  // spendResource();

  // Get the atom
  bool polarity = literal.getKind() != kind::NOT;
  TNode atom = polarity ? literal : literal[0];

  if (d_logicInfo.isSharingEnabled() && atom.getKind() == kind::EQUAL) {
    if (d_propEngine->isSatLiteral(literal)) {
      // We propagate SAT literals to SAT
      assertToTheory(literal, literal, /* to */ THEORY_SAT_SOLVER, /* from */ theory);
    }
    if (theory != THEORY_BUILTIN) {
      // Assert to the shared terms database
      assertToTheory(literal, literal, /* to */ THEORY_BUILTIN, /* from */ theory);
    }
  } else {
    // Just send off to the SAT solver
    Assert(d_propEngine->isSatLiteral(literal));
    assertToTheory(literal, literal, /* to */ THEORY_SAT_SOLVER, /* from */ theory);
  }

  return !d_inConflict;
}

const LogicInfo& TheoryEngine::getLogicInfo() const { return d_logicInfo; }

bool TheoryEngine::getSepHeapTypes(TypeNode& locType, TypeNode& dataType) const
{
  if (d_sepLocType.isNull())
  {
    return false;
  }
  locType = d_sepLocType;
  dataType = d_sepDataType;
  return true;
}

void TheoryEngine::declareSepHeap(TypeNode locT, TypeNode dataT)
{
  Theory* tsep = theoryOf(THEORY_SEP);
  if (tsep == nullptr)
  {
    Assert(false) << "TheoryEngine::declareSepHeap called without the "
                     "separation logic theory enabled";
    return;
  }

  // Definition of the statement that is to be run by every theory
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY) \
  theoryOf(THEORY)->declareSepHeap(locT, dataT);

  // notify each theory using the statement above
  CVC5_FOR_EACH_THEORY;

  // remember the types we have set
  d_sepLocType = locT;
  d_sepDataType = dataT;
}

theory::EqualityStatus TheoryEngine::getEqualityStatus(TNode a, TNode b) {
  Assert(a.getType().isComparableTo(b.getType()));
  return d_sharedSolver->getEqualityStatus(a, b);
}

const std::unordered_set<TNode>& TheoryEngine::getRelevantAssertions(
    bool& success)
{
  // if we are not in SAT mode, or there is no relevance manager, we fail
  if (!d_inSatMode || d_relManager == nullptr)
  {
    success = false;
    return d_emptyRelevantSet;
  }
  return d_relManager->getRelevantAssertions(success);
}

void TheoryEngine::getDifficultyMap(std::map<Node, Node>& dmap)
{
  Assert(d_relManager != nullptr);
  d_relManager->getDifficultyMap(dmap);
}

Node TheoryEngine::getModelValue(TNode var) {
  if (var.isConst())
  {
    // the model value of a constant must be itself
    return var;
  }
  Assert(d_sharedSolver->isShared(var));
  return theoryOf(Theory::theoryOf(var.getType()))->getModelValue(var);
}

TrustNode TheoryEngine::getExplanation(TNode node)
{
  Debug("theory::explain") << "TheoryEngine::getExplanation(" << node
                           << "): current propagation index = "
                           << d_propagationMapTimestamp << endl;
  bool polarity = node.getKind() != kind::NOT;
  TNode atom = polarity ? node : node[0];

  // If we're not in shared mode, explanations are simple
  if (!d_logicInfo.isSharingEnabled())
  {
    Debug("theory::explain")
        << "TheoryEngine::getExplanation: sharing is NOT enabled. "
        << " Responsible theory is: " << theoryOf(atom)->getId() << std::endl;

    TrustNode texplanation = theoryOf(atom)->explain(node);
    Node explanation = texplanation.getNode();
    Debug("theory::explain") << "TheoryEngine::getExplanation(" << node
                             << ") => " << explanation << endl;
    if (isProofEnabled())
    {
      texplanation.debugCheckClosed(
          "te-proof-exp", "texplanation no share", false);
      // check if no generator, if so, add THEORY_LEMMA
      if (texplanation.getGenerator() == nullptr)
      {
        Node proven = texplanation.getProven();
        TheoryId tid = theoryOf(atom)->getId();
        Node tidn = builtin::BuiltinProofRuleChecker::mkTheoryIdNode(tid);
        d_lazyProof->addStep(proven, PfRule::THEORY_LEMMA, {}, {proven, tidn});
        texplanation =
            TrustNode::mkTrustPropExp(node, explanation, d_lazyProof.get());
      }
    }
    return texplanation;
  }

  Debug("theory::explain") << "TheoryEngine::getExplanation: sharing IS enabled"
                           << std::endl;

  // Initial thing to explain
  NodeTheoryPair toExplain(node, THEORY_SAT_SOLVER, d_propagationMapTimestamp);
  Assert(d_propagationMap.find(toExplain) != d_propagationMap.end());

  NodeTheoryPair nodeExplainerPair = d_propagationMap[toExplain];
  Debug("theory::explain")
      << "TheoryEngine::getExplanation: explainer for node "
      << nodeExplainerPair.d_node
      << " is theory: " << nodeExplainerPair.d_theory << std::endl;

  // Create the workplace for explanations
  std::vector<NodeTheoryPair> vec{d_propagationMap[toExplain]};
  // Process the explanation
  TrustNode texplanation = getExplanation(vec);
  Debug("theory::explain") << "TheoryEngine::getExplanation(" << node << ") => "
                           << texplanation.getNode() << endl;
  return texplanation;
}

struct AtomsCollect {

  std::vector<TNode> d_atoms;
  std::unordered_set<TNode> d_visited;

 public:
  typedef void return_type;

  bool alreadyVisited(TNode current, TNode parent) {
    // Check if already visited
    if (d_visited.find(current) != d_visited.end()) return true;
    // Don't visit non-boolean
    if (!current.getType().isBoolean()) return true;
    // New node
    return false;
  }

  void visit(TNode current, TNode parent) {
    if (Theory::theoryOf(current) != theory::THEORY_BOOL) {
      d_atoms.push_back(current);
    }
    d_visited.insert(current);
  }

  void start(TNode node) {}
  void done(TNode node) {}

  std::vector<TNode> getAtoms() const {
    return d_atoms;
  }
};

void TheoryEngine::ensureLemmaAtoms(TNode n, theory::TheoryId atomsTo)
{
  Assert(atomsTo != THEORY_LAST);
  Debug("theory::atoms") << "TheoryEngine::ensureLemmaAtoms(" << n << ", "
                         << atomsTo << ")" << endl;
  AtomsCollect collectAtoms;
  NodeVisitor<AtomsCollect>::run(collectAtoms, n);
  ensureLemmaAtoms(collectAtoms.getAtoms(), atomsTo);
}

void TheoryEngine::ensureLemmaAtoms(const std::vector<TNode>& atoms, theory::TheoryId atomsTo) {
  for (unsigned i = 0; i < atoms.size(); ++ i) {

    // Non-equality atoms are either owned by theory or they don't make sense
    if (atoms[i].getKind() != kind::EQUAL) {
      continue;
    }

    // The equality
    Node eq = atoms[i];
    // Simple normalization to not repeat stuff
    if (eq[0] > eq[1]) {
      eq = eq[1].eqNode(eq[0]);
    }

    // Rewrite the equality
    Node eqNormalized = Rewriter::rewrite(atoms[i]);

    Debug("theory::atoms") << "TheoryEngine::ensureLemmaAtoms(): " << eq
                           << " with nf " << eqNormalized << endl;

    // If the equality is a boolean constant, we send immediately
    if (eqNormalized.isConst()) {
      if (eqNormalized.getConst<bool>()) {
        assertToTheory(eq, eqNormalized, /** to */ atomsTo, /** Sat solver */ theory::THEORY_SAT_SOLVER);
      } else {
        assertToTheory(eq.notNode(), eqNormalized.notNode(), /** to */ atomsTo, /** Sat solver */ theory::THEORY_SAT_SOLVER);
      }
      continue;
    }else if( eqNormalized.getKind() != kind::EQUAL){
      Assert(eqNormalized.getKind() == kind::BOOLEAN_TERM_VARIABLE
             || (eqNormalized.getKind() == kind::NOT
                 && eqNormalized[0].getKind() == kind::BOOLEAN_TERM_VARIABLE));
      // this happens for Boolean term equalities V = true that are rewritten to V, we should skip
      //  TODO : revisit this
      continue;
    }

    // If the normalization did the just flips, keep the flip
    if (eqNormalized[0] == eq[1] && eqNormalized[1] == eq[0]) {
      eq = eqNormalized;
    }

    // Check if the equality is already known by the sat solver
    if (d_propEngine->isSatLiteral(eqNormalized)) {
      bool value;
      if (d_propEngine->hasValue(eqNormalized, value)) {
        if (value) {
          assertToTheory(eq, eqNormalized, atomsTo, theory::THEORY_SAT_SOLVER);
          continue;
        } else {
          assertToTheory(eq.notNode(), eqNormalized.notNode(), atomsTo, theory::THEORY_SAT_SOLVER);
          continue;
        }
      }
    }

    // If the theory is asking about a different form, or the form is ok but if will go to a different theory
    // then we must figure it out
    if (eqNormalized != eq || Theory::theoryOf(eq) != atomsTo) {
      // If you get eqNormalized, send atoms[i] to atomsTo
      d_atomRequests.add(eqNormalized, eq, atomsTo);
    }
  }
}

void TheoryEngine::lemma(TrustNode tlemma,
                         theory::LemmaProperty p,
                         theory::TheoryId from)
{
  // For resource-limiting (also does a time check).
  // spendResource();
  Assert(tlemma.getKind() == TrustNodeKind::LEMMA
         || tlemma.getKind() == TrustNodeKind::CONFLICT);
  // get the node
  Node node = tlemma.getNode();
  Node lemma = tlemma.getProven();

  Assert(!expr::hasFreeVar(lemma));

  // when proofs are enabled, we ensure the trust node has a generator by
  // adding a trust step to the lazy proof maintained by this class
  if (isProofEnabled())
  {
    // ensure proof: set THEORY_LEMMA if no generator is provided
    if (tlemma.getGenerator() == nullptr)
    {
      // internal lemmas should have generators
      Assert(from != THEORY_LAST);
      // add theory lemma step to proof
      Node tidn = builtin::BuiltinProofRuleChecker::mkTheoryIdNode(from);
      d_lazyProof->addStep(lemma, PfRule::THEORY_LEMMA, {}, {lemma, tidn});
      // update the trust node
      tlemma = TrustNode::mkTrustLemma(lemma, d_lazyProof.get());
    }
    // ensure closed
    tlemma.debugCheckClosed("te-proof-debug", "TheoryEngine::lemma_initial");
  }

  // assert the lemma
  d_propEngine->assertLemma(tlemma, p);

  // If specified, we must add this lemma to the set of those that need to be
  // justified, where note we pass all auxiliary lemmas in skAsserts as well,
  // since these by extension must be justified as well.
  if (d_relManager != nullptr)
  {
    std::vector<Node> skAsserts;
    std::vector<Node> sks;
    Node retLemma =
        d_propEngine->getPreprocessedTerm(tlemma.getProven(), skAsserts, sks);
    if (isLemmaPropertyNeedsJustify(p))
    {
      d_relManager->notifyPreprocessedAssertion(retLemma);
      d_relManager->notifyPreprocessedAssertions(skAsserts);
    }
    d_relManager->notifyLemma(retLemma);
  }

  // Mark that we added some lemmas
  d_lemmasAdded = true;
}

void TheoryEngine::markInConflict()
{
#ifdef CVC5_FOR_EACH_THEORY_STATEMENT
#undef CVC5_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC5_FOR_EACH_THEORY_STATEMENT(THEORY) \
  theoryOf(THEORY)->notifyInConflict();
  CVC5_FOR_EACH_THEORY;
  d_inConflict = true;
}

void TheoryEngine::conflict(TrustNode tconflict, TheoryId theoryId)
{
  Assert(tconflict.getKind() == TrustNodeKind::CONFLICT);

  TNode conflict = tconflict.getNode();
  Debug("theory::conflict") << "TheoryEngine::conflict(" << conflict << ", "
                            << theoryId << ")" << endl;
  Trace("te-proof-debug") << "Check closed conflict" << std::endl;
  // doesn't require proof generator, yet, since THEORY_LEMMA is added below
  tconflict.debugCheckClosed(
      "te-proof-debug", "TheoryEngine::conflict_initial", false);

  Trace("dtview::conflict") << ":THEORY-CONFLICT: " << conflict << std::endl;

  // Mark that we are in conflict
  markInConflict();

  // In the multiple-theories case, we need to reconstruct the conflict
  if (d_logicInfo.isSharingEnabled()) {
    // Create the workplace for explanations
    std::vector<NodeTheoryPair> vec;
    vec.push_back(
        NodeTheoryPair(conflict, theoryId, d_propagationMapTimestamp));

    // Process the explanation
    TrustNode tncExp = getExplanation(vec);
    Node fullConflict = tncExp.getNode();

    if (isProofEnabled())
    {
      Trace("te-proof-debug")
          << "Check closed conflict explained with sharing" << std::endl;
      tncExp.debugCheckClosed("te-proof-debug",
                              "TheoryEngine::conflict_explained_sharing");
      Trace("te-proof-debug") << "Process conflict: " << conflict << std::endl;
      Trace("te-proof-debug") << "Conflict " << tconflict << " from "
                              << tconflict.identifyGenerator() << std::endl;
      Trace("te-proof-debug") << "Explanation " << tncExp << " from "
                              << tncExp.identifyGenerator() << std::endl;
      Assert(d_lazyProof != nullptr);
      if (tconflict.getGenerator() != nullptr)
      {
        d_lazyProof->addLazyStep(tconflict.getProven(),
                                 tconflict.getGenerator());
      }
      else
      {
        // add theory lemma step
        Node tidn = builtin::BuiltinProofRuleChecker::mkTheoryIdNode(theoryId);
        Node conf = tconflict.getProven();
        d_lazyProof->addStep(conf, PfRule::THEORY_LEMMA, {}, {conf, tidn});
      }
      // store the explicit step, which should come from a different
      // generator, e.g. d_tepg.
      Node proven = tncExp.getProven();
      Assert(tncExp.getGenerator() != d_lazyProof.get());
      Trace("te-proof-debug") << "add lazy step " << tncExp.identifyGenerator()
                              << " for " << proven << std::endl;
      d_lazyProof->addLazyStep(proven, tncExp.getGenerator());
      pfgEnsureClosed(proven,
                      d_lazyProof.get(),
                      "te-proof-debug",
                      "TheoryEngine::conflict_during");
      Node fullConflictNeg = fullConflict.notNode();
      std::vector<Node> children;
      children.push_back(proven);
      std::vector<Node> args;
      args.push_back(fullConflictNeg);
      if (conflict == d_false)
      {
        AlwaysAssert(proven == fullConflictNeg);
      }
      else
      {
        if (!CDProof::isSame(fullConflict, conflict))
        {
          // ------------------------- explained  ---------- from theory
          // fullConflict => conflict              ~conflict
          // ------------------------------------------ MACRO_SR_PRED_TRANSFORM
          // ~fullConflict
          children.push_back(conflict.notNode());
          args.push_back(mkMethodId(MethodId::SB_LITERAL));
          d_lazyProof->addStep(
              fullConflictNeg, PfRule::MACRO_SR_PRED_TRANSFORM, children, args);
        }
      }
    }
    // pass the processed trust node
    TrustNode tconf =
        TrustNode::mkTrustConflict(fullConflict, d_lazyProof.get());
    Debug("theory::conflict")
        << "TheoryEngine::conflict(" << conflict << ", " << theoryId
        << "): full = " << fullConflict << endl;
    Assert(properConflict(fullConflict));
    Trace("te-proof-debug")
        << "Check closed conflict with sharing" << std::endl;
    if (isProofEnabled())
    {
      tconf.debugCheckClosed("te-proof-debug", "TheoryEngine::conflict:sharing");
    }
    lemma(tconf, LemmaProperty::REMOVABLE);
  } else {
    // When only one theory, the conflict should need no processing
    Assert(properConflict(conflict));
    // pass the trust node that was sent from the theory
    lemma(tconflict, LemmaProperty::REMOVABLE, theoryId);
  }
}

void TheoryEngine::setIncomplete(theory::TheoryId theory,
                                 theory::IncompleteId id)
{
  d_incomplete = true;
  d_incompleteTheory = theory;
  d_incompleteId = id;
}

TrustNode TheoryEngine::getExplanation(
    std::vector<NodeTheoryPair>& explanationVector)
{
  Assert(explanationVector.size() == 1);
  Node conclusion = explanationVector[0].d_node;
  // if the theory explains using the central equality engine, we always start
  // with THEORY_BUILTIN.
  if (Theory::expUsingCentralEqualityEngine(explanationVector[0].d_theory))
  {
    explanationVector[0].d_theory = THEORY_BUILTIN;
  }
  std::shared_ptr<LazyCDProof> lcp;
  if (isProofEnabled())
  {
    Trace("te-proof-exp") << "=== TheoryEngine::getExplanation " << conclusion
                          << std::endl;
    // We do not use auto-symmetry in this proof, since in very rare cases, it
    // is possible that the proof of explanations is cyclic when considering
    // (dis)equalities modulo symmetry, where such a proof looks like:
    // x = y
    // -----
    //   A    ...
    // ----------
    //   y = x
    // Notice that this complication arises since propagations consider
    // equalities that are not in rewritten form. This complication would not
    // exist otherwise. It is the shared term database that introduces these
    // unrewritten equalities; it must do so since theory combination requires
    // communicating arrangements between shared terms, and the rewriter
    // for arithmetic equalities does not preserve terms, e.g. x=y may become
    // x+-1*y=0.
    lcp.reset(new LazyCDProof(d_pnm,
                              nullptr,
                              nullptr,
                              "TheoryEngine::LazyCDProof::getExplanation",
                              false));
  }
  unsigned i = 0; // Index of the current literal we are processing

  std::unique_ptr<std::set<Node>> inputAssertions = nullptr;
  // the overall explanation
  std::set<TNode> exp;
  // vector of trust nodes to explain at the end
  std::vector<std::pair<TheoryId, TrustNode>> texplains;
  // cache of nodes we have already explained by some theory
  std::unordered_map<Node, size_t> cache;

  while (i < explanationVector.size()) {
    // Get the current literal to explain
    NodeTheoryPair toExplain = explanationVector[i];

    Debug("theory::explain")
        << "[i=" << i << "] TheoryEngine::explain(): processing ["
        << toExplain.d_timestamp << "] " << toExplain.d_node << " sent from "
        << toExplain.d_theory << endl;

    if (cache.find(toExplain.d_node) != cache.end()
        && cache[toExplain.d_node] < toExplain.d_timestamp)
    {
      ++i;
      continue;
    }
    cache[toExplain.d_node] = toExplain.d_timestamp;

    // If a true constant or a negation of a false constant we can ignore it
    if ((toExplain.d_node.isConst() && toExplain.d_node.getConst<bool>())
        || (toExplain.d_node.getKind() == kind::NOT
            && toExplain.d_node[0].isConst()
            && !toExplain.d_node[0].getConst<bool>()))
    {
      ++ i;
      // if we are building a proof
      if (lcp != nullptr)
      {
        Trace("te-proof-exp")
            << "- explain " << toExplain.d_node << " trivially..." << std::endl;
        // ------------------MACRO_SR_PRED_INTRO
        // toExplain.d_node
        std::vector<Node> children;
        std::vector<Node> args;
        args.push_back(toExplain.d_node);
        lcp->addStep(
            toExplain.d_node, PfRule::MACRO_SR_PRED_INTRO, children, args);
      }
      continue;
    }

    // If from the SAT solver, keep it
    if (toExplain.d_theory == THEORY_SAT_SOLVER)
    {
      Debug("theory::explain")
          << "\tLiteral came from THEORY_SAT_SOLVER. Keeping it." << endl;
      exp.insert(explanationVector[i++].d_node);
      // it will be a free assumption in the proof
      Trace("te-proof-exp") << "- keep " << toExplain.d_node << std::endl;
      continue;
    }

    // If an and, expand it
    if (toExplain.d_node.getKind() == kind::AND)
    {
      Debug("theory::explain")
          << "TheoryEngine::explain(): expanding " << toExplain.d_node
          << " got from " << toExplain.d_theory << endl;
      size_t nchild = toExplain.d_node.getNumChildren();
      for (size_t k = 0; k < nchild; ++k)
      {
        NodeTheoryPair newExplain(
            toExplain.d_node[k], toExplain.d_theory, toExplain.d_timestamp);
        explanationVector.push_back(newExplain);
      }
      if (lcp != nullptr)
      {
        Trace("te-proof-exp")
            << "- AND expand " << toExplain.d_node << std::endl;
        // delay explanation, use a dummy trust node
        TrustNode tnAndExp = TrustNode::mkTrustPropExp(
            toExplain.d_node, toExplain.d_node, nullptr);
        texplains.push_back(
            std::pair<TheoryId, TrustNode>(THEORY_LAST, tnAndExp));
      }
      ++ i;
      continue;
    }

    // See if it was sent to the theory by another theory
    PropagationMap::const_iterator find = d_propagationMap.find(toExplain);
    if (find != d_propagationMap.end()) {
      Debug("theory::explain")
          << "\tTerm was propagated by another theory (theory = "
          << getTheoryString((*find).second.d_theory) << ")" << std::endl;
      // There is some propagation, check if its a timely one
      if ((*find).second.d_timestamp < toExplain.d_timestamp)
      {
        Debug("theory::explain")
            << "\tRelevant timetsamp, pushing " << (*find).second.d_node
            << "to index = " << explanationVector.size() << std::endl;
        explanationVector.push_back((*find).second);
        ++i;

        if (lcp != nullptr)
        {
          if (toExplain.d_node != (*find).second.d_node)
          {
            Trace("te-proof-exp")
                << "- t-explained cached: " << toExplain.d_node << " by "
                << (*find).second.d_node << std::endl;
            // delay explanation, use a dummy trust node that says that
            // (*find).second.d_node explains toExplain.d_node.
            TrustNode tnRewExp = TrustNode::mkTrustPropExp(
                toExplain.d_node, (*find).second.d_node, nullptr);
            texplains.push_back(
                std::pair<TheoryId, TrustNode>(THEORY_LAST, tnRewExp));
          }
        }
        continue;
      }
    }
    // It was produced by the theory, so ask for an explanation
    TrustNode texplanation =
        d_sharedSolver->explain(toExplain.d_node, toExplain.d_theory);
    if (lcp != nullptr)
    {
      texplanation.debugCheckClosed("te-proof-exp", "texplanation", false);
      Trace("te-proof-exp")
          << "- t-explained[" << toExplain.d_theory << "]: " << toExplain.d_node
          << " by " << texplanation.getNode() << std::endl;
      // should prove the propagation we asked for
      Assert(texplanation.getKind() == TrustNodeKind::PROP_EXP
             && texplanation.getProven()[1] == toExplain.d_node);
      // We add it to the list of theory explanations, to be processed at
      // the end of this method. We wait to explain here because it may
      // be that a later explanation may preempt the need for proving this
      // step. For instance, if the conclusion lit is later added as an
      // assumption in the final explanation. This avoids cyclic proofs.
      texplains.push_back(
          std::pair<TheoryId, TrustNode>(toExplain.d_theory, texplanation));
    }
    Node explanation = texplanation.getNode();

    Debug("theory::explain")
        << "TheoryEngine::explain(): got explanation " << explanation
        << " got from " << toExplain.d_theory << endl;
    Assert(explanation != toExplain.d_node)
        << "wasn't sent to you, so why are you explaining it trivially, for "
           "fact "
        << explanation;
    // Mark the explanation
    NodeTheoryPair newExplain(
        explanation, toExplain.d_theory, toExplain.d_timestamp);
    explanationVector.push_back(newExplain);

    ++ i;
  }

  // make the explanation node
  Node expNode;
  if (exp.size() == 0)
  {
    // Normalize to true
    expNode = NodeManager::currentNM()->mkConst<bool>(true);
  }
  else if (exp.size() == 1)
  {
    // All the same, or just one
    expNode = *exp.begin();
  }
  else
  {
    NodeBuilder conjunction(kind::AND);
    std::set<TNode>::const_iterator it = exp.begin();
    std::set<TNode>::const_iterator it_end = exp.end();
    while (it != it_end)
    {
      conjunction << *it;
      ++it;
    }
    expNode = conjunction;
  }
  // if we are building a proof, go back through the explanations and
  // build the proof
  if (lcp != nullptr)
  {
    if (Trace.isOn("te-proof-exp"))
    {
      Trace("te-proof-exp") << "Explanation is:" << std::endl;
      for (TNode e : exp)
      {
        Trace("te-proof-exp") << "  " << e << std::endl;
      }
      Trace("te-proof-exp") << "=== Replay explanations..." << std::endl;
    }
    // Now, go back and add the necessary steps of theory explanations, i.e.
    // add those that prove things that aren't in the final explanation. We
    // iterate in reverse order so that most recent steps take priority. This
    // avoids cyclic proofs in the lazy proof we are building (lcp).
    for (std::vector<std::pair<TheoryId, TrustNode>>::reverse_iterator
             it = texplains.rbegin(),
             itEnd = texplains.rend();
         it != itEnd;
         ++it)
    {
      TrustNode trn = it->second;
      Assert(trn.getKind() == TrustNodeKind::PROP_EXP);
      Node proven = trn.getProven();
      Assert(proven.getKind() == kind::IMPLIES);
      Node tConc = proven[1];
      Trace("te-proof-exp") << "- Process " << trn << std::endl;
      if (exp.find(tConc) != exp.end())
      {
        // already added to proof
        Trace("te-proof-exp") << "...already added" << std::endl;
        continue;
      }
      // remember that we've explained this formula, to avoid cycles in lcp
      exp.insert(tConc);
      TheoryId ttid = it->first;
      Node tExp = proven[0];
      if (ttid == THEORY_LAST)
      {
        if (tConc == tExp)
        {
          // dummy trust node, do AND expansion
          Assert(tConc.getKind() == kind::AND);
          // tConc[0] ... tConc[n]
          // ---------------------- AND_INTRO
          // tConc
          std::vector<Node> pfChildren;
          pfChildren.insert(pfChildren.end(), tConc.begin(), tConc.end());
          lcp->addStep(tConc, PfRule::AND_INTRO, pfChildren, {});
          Trace("te-proof-exp") << "...via AND_INTRO" << std::endl;
          continue;
        }
        // otherwise should hold by rewriting
        Assert(Rewriter::rewrite(tConc) == Rewriter::rewrite(tExp));
        // tExp
        // ---- MACRO_SR_PRED_TRANSFORM
        // tConc
        lcp->addStep(tConc, PfRule::MACRO_SR_PRED_TRANSFORM, {tExp}, {tConc});
        Trace("te-proof-exp") << "...via MACRO_SR_PRED_TRANSFORM" << std::endl;
        continue;
      }
      if (tExp == tConc)
      {
        // trivial
        Trace("te-proof-exp") << "...trivial" << std::endl;
        continue;
      }
      //       ------------- Via theory
      // tExp  tExp => tConc
      // ---------------------------------MODUS_PONENS
      // tConc
      if (trn.getGenerator() != nullptr)
      {
        Trace("te-proof-exp") << "...via theory generator" << std::endl;
        lcp->addLazyStep(proven, trn.getGenerator());
      }
      else
      {
        Trace("te-proof-exp") << "...via trust THEORY_LEMMA" << std::endl;
        // otherwise, trusted theory lemma
        Node tidn = builtin::BuiltinProofRuleChecker::mkTheoryIdNode(ttid);
        lcp->addStep(proven, PfRule::THEORY_LEMMA, {}, {proven, tidn});
      }
      std::vector<Node> pfChildren;
      pfChildren.push_back(trn.getNode());
      pfChildren.push_back(proven);
      lcp->addStep(tConc, PfRule::MODUS_PONENS, pfChildren, {});
    }
    // If we don't have a step and the conclusion is not part of the
    // explanation (for unit T-conflicts), it must be by symmetry. We must do
    // this manually since lcp does not have auto-symmetry enabled due to the
    // complication mentioned above.
    if (!lcp->hasStep(conclusion) && exp.find(conclusion) == exp.end())
    {
      Node sconc = CDProof::getSymmFact(conclusion);
      if (!sconc.isNull())
      {
        lcp->addStep(conclusion, PfRule::SYMM, {sconc}, {});
      }
      else
      {
        Assert(false)
            << "TheoryEngine::getExplanation: no step found for conclusion "
            << conclusion;
      }
    }
    // store in the proof generator
    TrustNode trn = d_tepg->mkTrustExplain(conclusion, expNode, lcp);
    // return the trust node
    return trn;
  }

  return TrustNode::mkTrustPropExp(conclusion, expNode, nullptr);
}

bool TheoryEngine::isProofEnabled() const { return d_pnm != nullptr; }

void TheoryEngine::checkTheoryAssertionsWithModel(bool hardFailure) {
  for(TheoryId theoryId = THEORY_FIRST; theoryId < THEORY_LAST; ++theoryId) {
    Theory* theory = d_theoryTable[theoryId];
    if(theory && d_logicInfo.isTheoryEnabled(theoryId)) {
      for(context::CDList<Assertion>::const_iterator it = theory->facts_begin(),
            it_end = theory->facts_end();
          it != it_end;
          ++it) {
        Node assertion = (*it).d_assertion;
        if (!isRelevant(assertion))
        {
          // not relevant, skip
          continue;
        }
        Node val = d_tc->getModel()->getValue(assertion);
        if (val != d_true)
        {
          std::stringstream ss;
          ss << " " << theoryId
             << " has an asserted fact that the model doesn't satisfy." << endl
             << "The fact: " << assertion << endl
             << "Model value: " << val << endl;
          if (hardFailure)
          {
            if (val == d_false)
            {
              // Always an error if it is false
              InternalError() << ss.str();
            }
            else
            {
              // Otherwise just a warning. Notice this case may happen for
              // assertions with unevaluable operators, e.g. transcendental
              // functions. It also may happen for separation logic, where
              // check-model support is limited.
              warning() << ss.str();
            }
          }
        }
      }
    }
  }
}

std::pair<bool, Node> TheoryEngine::entailmentCheck(options::TheoryOfMode mode,
                                                    TNode lit)
{
  TNode atom = (lit.getKind() == kind::NOT) ? lit[0] : lit;
  if( atom.getKind()==kind::AND || atom.getKind()==kind::OR || atom.getKind()==kind::IMPLIES ){
    //Boolean connective, recurse
    std::vector< Node > children;
    bool pol = (lit.getKind()!=kind::NOT);
    bool is_conjunction = pol==(lit.getKind()==kind::AND);
    for( unsigned i=0; i<atom.getNumChildren(); i++ ){
      Node ch = atom[i];
      if( pol==( lit.getKind()==kind::IMPLIES && i==0 ) ){
        ch = atom[i].negate();
      }
      std::pair<bool, Node> chres = entailmentCheck(mode, ch);
      if( chres.first ){
        if( !is_conjunction ){
          return chres;
        }else{
          children.push_back( chres.second );
        }
      }else if( !chres.first && is_conjunction ){
        return std::pair<bool, Node>(false, Node::null());
      }
    }
    if( is_conjunction ){
      return std::pair<bool, Node>(true, NodeManager::currentNM()->mkNode(kind::AND, children));
    }else{
      return std::pair<bool, Node>(false, Node::null());
    }
  }else if( atom.getKind()==kind::ITE || ( atom.getKind()==kind::EQUAL && atom[0].getType().isBoolean() ) ){
    bool pol = (lit.getKind()!=kind::NOT);
    for( unsigned r=0; r<2; r++ ){
      Node ch = atom[0];
      if( r==1 ){
        ch = ch.negate();
      }
      std::pair<bool, Node> chres = entailmentCheck(mode, ch);
      if( chres.first ){
        Node ch2 = atom[ atom.getKind()==kind::ITE ? r+1 : 1 ];
        if( pol==( atom.getKind()==kind::ITE ? true : r==1 ) ){
          ch2 = ch2.negate();
        }
        std::pair<bool, Node> chres2 = entailmentCheck(mode, ch2);
        if( chres2.first ){
          return std::pair<bool, Node>(true, NodeManager::currentNM()->mkNode(kind::AND, chres.second, chres2.second));
        }else{
          break;
        }
      }
    }
    return std::pair<bool, Node>(false, Node::null());
  }else{
    //it is a theory atom
    theory::TheoryId tid = theory::Theory::theoryOf(mode, atom);
    theory::Theory* th = theoryOf(tid);

    Assert(th != NULL);
    Trace("theory-engine-entc") << "Entailment check : " << lit << std::endl;

    std::pair<bool, Node> chres = th->entailmentCheck(lit);
    return chres;
  }
}

void TheoryEngine::spendResource(Resource r)
{
  d_env.getResourceManager()->spendResource(r);
}

void TheoryEngine::initializeProofChecker(ProofChecker* pc)
{
  for (theory::TheoryId id = theory::THEORY_FIRST; id < theory::THEORY_LAST;
       ++id)
  {
    ProofRuleChecker* prc = d_theoryTable[id]->getProofChecker();
    if (prc)
    {
      prc->registerTo(pc);
    }
  }
}

theory::Rewriter* TheoryEngine::getRewriter() { return d_env.getRewriter(); }

}  // namespace cvc5

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