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|
/********************* */
/*! \file theory_engine.cpp
** \verbatim
** Original author: mdeters
** Major contributors: barrett, dejan
** Minor contributors (to current version): cconway, taking
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief The theory engine.
**
** The theory engine.
**/
#include <vector>
#include <list>
#include "decision/decision_engine.h"
#include "expr/attribute.h"
#include "expr/node.h"
#include "expr/node_builder.h"
#include "util/options.h"
#include "util/lemma_output_channel.h"
#include "theory/theory.h"
#include "theory/theory_engine.h"
#include "theory/rewriter.h"
#include "theory/theory_traits.h"
#include "util/node_visitor.h"
#include "util/ite_removal.h"
#include "theory/model.h"
#include "theory/quantifiers_engine.h"
#include "theory/quantifiers/theory_quantifiers.h"
#include "theory/quantifiers/model_engine.h"
#include "theory/quantifiers/first_order_model.h"
using namespace std;
using namespace CVC4;
using namespace CVC4::theory;
TheoryEngine::TheoryEngine(context::Context* context,
context::UserContext* userContext,
const LogicInfo& logicInfo)
: d_propEngine(NULL),
d_decisionEngine(NULL),
d_context(context),
d_userContext(userContext),
d_logicInfo(logicInfo),
d_sharedTerms(this, context),
d_quantEngine(NULL),
d_curr_model(NULL),
d_curr_model_builder(NULL),
d_ppCache(),
d_possiblePropagations(context),
d_hasPropagated(context),
d_inConflict(context, false),
d_hasShutDown(false),
d_incomplete(context, false),
d_propagationMap(context),
d_propagationMapTimestamp(context, 0),
d_propagatedLiterals(context),
d_propagatedLiteralsIndex(context, 0),
d_decisionRequests(context),
d_decisionRequestsIndex(context, 0),
d_combineTheoriesTime("TheoryEngine::combineTheoriesTime"),
d_inPreregister(false),
d_factsAsserted(context, false),
d_preRegistrationVisitor(this, context),
d_sharedTermsVisitor(d_sharedTerms),
d_unconstrainedSimp(context, logicInfo)
{
for(TheoryId theoryId = theory::THEORY_FIRST; theoryId != theory::THEORY_LAST; ++ theoryId) {
d_theoryTable[theoryId] = NULL;
d_theoryOut[theoryId] = NULL;
}
// initialize the quantifiers engine
d_quantEngine = new QuantifiersEngine(context, this);
//build model information if applicable
d_curr_model = new theory::DefaultModel( context, "DefaultModel" );
d_curr_model_builder = new theory::TheoryEngineModelBuilder( this );
Rewriter::init();
StatisticsRegistry::registerStat(&d_combineTheoriesTime);
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];
}
}
delete d_quantEngine;
StatisticsRegistry::unregisterStat(&d_combineTheoriesTime);
}
void TheoryEngine::preRegister(TNode preprocessed) {
if(Dump.isOn("missed-t-propagations")) {
d_possiblePropagations.push_back(preprocessed);
}
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();
if (d_logicInfo.isSharingEnabled() && preprocessed.getKind() == kind::EQUAL) {
// When sharing is enabled, we propagate from the shared terms manager also
d_sharedTerms.addEqualityToPropagate(preprocessed);
}
// Pre-register the terms in the atom
bool multipleTheories = NodeVisitor<PreRegisterVisitor>::run(d_preRegistrationVisitor, preprocessed);
if (multipleTheories) {
// Collect the shared terms if there are multipe theories
NodeVisitor<SharedTermsVisitor>::run(d_sharedTermsVisitor, preprocessed);
}
}
// Leaving pre-register
d_inPreregister = false;
}
}
void TheoryEngine::printAssertions(const char* tag) {
if (Debug.isOn(tag)) {
for (TheoryId theoryId = THEORY_FIRST; theoryId < THEORY_LAST; ++theoryId) {
Theory* theory = d_theoryTable[theoryId];
if (theory && d_logicInfo.isTheoryEnabled(theoryId)) {
Debug(tag) << "--------------------------------------------" << std::endl;
Debug(tag) << "Assertions of " << theory->getId() << ": " << std::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).isPreregistered) {
Debug(tag) << "[" << i << "]: ";
} else {
Debug(tag) << "(" << i << "): ";
}
Debug(tag) << (*it).assertion << endl;
}
if (d_logicInfo.isSharingEnabled()) {
Debug(tag) << "Shared terms of " << theory->getId() << ": " << std::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) {
Debug(tag) << "[" << i << "]: " << (*it) << endl;
}
}
}
}
}
}
void TheoryEngine::dumpAssertions(const char* tag) {
if (Dump.isOn(tag)) {
Dump(tag) << CommentCommand("Starting completeness check");
for (TheoryId theoryId = THEORY_FIRST; theoryId < THEORY_LAST; ++theoryId) {
Theory* theory = d_theoryTable[theoryId];
if (theory && d_logicInfo.isTheoryEnabled(theoryId)) {
Dump(tag) << CommentCommand("Completeness check");
Dump(tag) << PushCommand();
// Dump the shared terms
if (d_logicInfo.isSharingEnabled()) {
Dump(tag) << CommentCommand("Shared terms");
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) {
stringstream ss;
ss << (*it);
Dump(tag) << CommentCommand(ss.str());
}
}
// Dump the assertions
Dump(tag) << CommentCommand("Assertions");
context::CDList<Assertion>::const_iterator it = theory->facts_begin(), it_end = theory->facts_end();
for (; it != it_end; ++ it) {
// Get the assertion
Node assertionNode = (*it).assertion;
// Purify all the terms
BoolExpr assertionExpr(assertionNode.toExpr());
if ((*it).isPreregistered) {
Dump(tag) << CommentCommand("Preregistered");
} else {
Dump(tag) << CommentCommand("Shared assertion");
}
Dump(tag) << AssertCommand(assertionExpr);
}
Dump(tag) << CheckSatCommand();
// Check for any missed propagations of shared terms
if (d_logicInfo.isSharingEnabled()) {
Dump(tag) << CommentCommand("Shared term equalities");
context::CDList<TNode>::const_iterator it = theory->shared_terms_begin(), it_end = theory->shared_terms_end();
for (; it != it_end; ++ it) {
TNode t1 = (*it);
context::CDList<TNode>::const_iterator it2 = it;
for (++ it2; it2 != it_end; ++ it2) {
TNode t2 = (*it2);
if (t1.getType() == t2.getType()) {
Node equality = t1.eqNode(t2);
if (d_sharedTerms.isKnown(equality)) {
continue;
}
Node disequality = equality.notNode();
if (d_sharedTerms.isKnown(disequality)) {
continue;
}
// Check equality
Dump(tag) << PushCommand();
BoolExpr eqExpr(equality.toExpr());
Dump(tag) << AssertCommand(eqExpr);
Dump(tag) << CheckSatCommand();
Dump(tag) << PopCommand();
// Check disequality
Dump(tag) << PushCommand();
BoolExpr diseqExpr(disequality.toExpr());
Dump(tag) << AssertCommand(diseqExpr);
Dump(tag) << CheckSatCommand();
Dump(tag) << PopCommand();
}
}
}
}
Dump(tag) << PopCommand();
}
}
}
}
template<typename T, bool doAssert>
class scoped_vector_clear {
vector<T>& d_v;
public:
scoped_vector_clear(vector<T>& v)
: d_v(v) {
Assert(!doAssert || d_v.empty());
}
~scoped_vector_clear() {
d_v.clear();
}
};
/**
* Check all (currently-active) theories for conflicts.
* @param effort the effort level to use
*/
void TheoryEngine::check(Theory::Effort effort) {
d_propEngine->checkTime();
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasCheck && d_logicInfo.isTheoryEnabled(THEORY)) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->check(effort); \
if (d_inConflict) { \
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") << std::endl;
// If in full effort, we have a fake new assertion just to jumpstart the checking
if (Theory::fullEffort(effort)) {
d_factsAsserted = true;
}
// Check until done
while (d_factsAsserted && !d_inConflict && !d_lemmasAdded) {
Debug("theory") << "TheoryEngine::check(" << effort << "): running check" << std::endl;
if (Debug.isOn("theory::assertions")) {
printAssertions("theory::assertions");
}
// Note that we've discharged all the facts
d_factsAsserted = false;
// Do the checking
CVC4_FOR_EACH_THEORY;
if(Dump.isOn("missed-t-conflicts")) {
Dump("missed-t-conflicts")
<< CommentCommand("Completeness check for T-conflicts; expect sat")
<< CheckSatCommand();
}
Debug("theory") << "TheoryEngine::check(" << effort << "): running propagation after the initial check" << std::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 && !d_lemmasAdded) {
// Do the combination
Debug("theory") << "TheoryEngine::check(" << effort << "): running combination" << std::endl;
combineTheories();
}
}
// Must consult quantifiers theory for last call to ensure sat, or otherwise add a lemma
if( effort == Theory::EFFORT_FULL &&
! d_inConflict &&
! d_lemmasAdded ) {
if( d_logicInfo.isQuantified() ){
((theory::quantifiers::TheoryQuantifiers*) d_theoryTable[THEORY_QUANTIFIERS])->performCheck(Theory::EFFORT_LAST_CALL);
// if we have given up, then possibly flip decision
if(Options::current()->flipDecision) {
if(d_incomplete && !d_inConflict && !d_lemmasAdded) {
if( ((theory::quantifiers::TheoryQuantifiers*) d_theoryTable[THEORY_QUANTIFIERS])->flipDecision() ) {
d_incomplete = false;
}
}
}
//if returning incomplete or SAT, we have ensured that the model in the quantifiers engine has been built
}else if( Options::current()->produceModels ){
//must build model at this point
d_curr_model_builder->buildModel( d_curr_model );
}
}
Debug("theory") << "TheoryEngine::check(" << effort << "): done, we are " << (d_inConflict ? "unsat" : "sat") << (d_lemmasAdded ? " with new lemmas" : " with no new lemmas") << std::endl;
} catch(const theory::Interrupted&) {
Trace("theory") << "TheoryEngine::check() => conflict" << endl;
}
// If fulleffort, check all theories
if(Dump.isOn("theory::fullcheck") && Theory::fullEffort(effort)) {
if (!d_inConflict && !d_lemmasAdded) {
dumpAssertions("theory::fullcheck");
}
}
}
void TheoryEngine::combineTheories() {
Debug("sharing") << "TheoryEngine::combineTheories()" << std::endl;
TimerStat::CodeTimer combineTheoriesTimer(d_combineTheoriesTime);
// Care graph we'll be building
CareGraph careGraph;
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::isParametric && d_logicInfo.isTheoryEnabled(THEORY)) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->getCareGraph(careGraph); \
}
// Call on each parametric theory to give us its care graph
CVC4_FOR_EACH_THEORY;
Debug("sharing") << "TheoryEngine::combineTheories(): care graph size = " << careGraph.size() << std::endl;
// Now add splitters for the ones we are interested in
CareGraph::const_iterator care_it = careGraph.begin();
CareGraph::const_iterator care_it_end = careGraph.end();
for (; care_it != care_it_end; ++ care_it) {
const CarePair& carePair = *care_it;
Debug("sharing") << "TheoryEngine::combineTheories(): checking " << carePair.a << " = " << carePair.b << " from " << carePair.theory << std::endl;
Assert(d_sharedTerms.isShared(carePair.a) || carePair.a.isConst());
Assert(d_sharedTerms.isShared(carePair.b) || carePair.b.isConst());
Assert(!d_sharedTerms.areEqual(carePair.a, carePair.b), "Please don't care about stuff you were notified about");
Assert(!d_sharedTerms.areDisequal(carePair.a, carePair.b), "Please don't care about stuff you were notified about");
// The equality in question
Node equality = carePair.a < carePair.b ?
carePair.a.eqNode(carePair.b) :
carePair.b.eqNode(carePair.a);
// Normalize the equality
Node normalizedEquality = Rewriter::rewrite(equality);
// Check if the normalized equality already has a value (this also
// covers constants, since they always have values
if (d_propEngine->isSatLiteral(normalizedEquality)) {
bool value;
if (d_propEngine->hasValue(normalizedEquality, value)) {
Assert(equality != normalizedEquality);
Node literal = value ? equality : equality.notNode();
Node normalizedLiteral = value ? normalizedEquality : normalizedEquality.notNode();
// We're sending the original literal back, backed by the normalized one
if (markPropagation(literal, normalizedLiteral, /* to */ carePair.theory, /* from */ THEORY_SAT_SOLVER)) {
// We assert it, and we know it's preregistereed if it's the same theory
bool preregistered = Theory::theoryOf(literal) == carePair.theory;
theoryOf(carePair.theory)->assertFact(literal, preregistered);
// Mark that we have more information
d_factsAsserted = true;
continue;
} else {
Unreachable();
}
}
}
// We need to split on it
Debug("sharing") << "TheoryEngine::combineTheories(): requesting a split " << std::endl;
lemma(equality.orNode(equality.notNode()), false, false);
}
}
void TheoryEngine::propagate(Theory::Effort effort) {
// Definition of the statement that is to be run by every theory
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasPropagate && d_logicInfo.isTheoryEnabled(THEORY)) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->propagate(effort); \
}
// Propagate for each theory using the statement above
CVC4_FOR_EACH_THEORY;
if(Dump.isOn("missed-t-propagations")) {
for(unsigned i = 0; i < d_possiblePropagations.size(); ++ i) {
Node atom = d_possiblePropagations[i];
bool value;
if (!d_propEngine->hasValue(atom, value)) continue;
// Doesn't have a value, check it (and the negation)
if(d_hasPropagated.find(atom) == d_hasPropagated.end()) {
Dump("missed-t-propagations")
<< CommentCommand("Completeness check for T-propagations; expect invalid")
<< QueryCommand(atom.toExpr())
<< QueryCommand(atom.notNode().toExpr());
}
}
}
}
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;
}
bool TheoryEngine::properPropagation(TNode lit) const {
if(!getPropEngine()->isTranslatedSatLiteral(lit)) {
return false;
}
bool b;
return !getPropEngine()->hasValue(lit, b);
}
bool TheoryEngine::properExplanation(TNode node, TNode expl) const {
// Explanation must be either a conjunction of true literals that have true SAT values already
// or a singled literal that has a true SAT value already.
if (expl.getKind() == kind::AND) {
for (unsigned i = 0; i < expl.getNumChildren(); ++ i) {
bool value;
if (!d_propEngine->hasValue(expl[i], value) || !value) {
return false;
}
}
} else {
bool value;
return d_propEngine->hasValue(expl, value) && value;
}
return true;
}
void TheoryEngine::collectModelInfo( theory::TheoryModel* m ){
//consult each theory to get all relevant information concerning the model
for( int i=0; i<theory::THEORY_LAST; i++ ){
if( d_theoryTable[i] ){
d_theoryTable[i]->collectModelInfo( m );
}
}
}
/* get model */
TheoryModel* TheoryEngine::getModel(){
Debug("model") << "TheoryEngine::getModel()" << std::endl;
if( d_logicInfo.isQuantified() ){
Debug("model") << "Get model from quantifiers engine." << std::endl;
return d_quantEngine->getModel();
}else{
Debug("model") << "Get default model." << std::endl;
return d_curr_model;
}
}
bool TheoryEngine::presolve() {
try {
// Definition of the statement that is to be run by every theory
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasPresolve) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->presolve(); \
if(d_inConflict) { \
return true; \
} \
}
// Presolve for each theory using the statement above
CVC4_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() {
try {
// Definition of the statement that is to be run by every theory
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasPostsolve) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->postsolve(); \
Assert(! d_inConflict, "conflict raised during postsolve()"); \
}
// Postsolve for each theory using the statement above
CVC4_FOR_EACH_THEORY;
} catch(const theory::Interrupted&) {
Trace("theory") << "TheoryEngine::postsolve() => interrupted" << endl;
}
}/* TheoryEngine::postsolve() */
void TheoryEngine::notifyRestart() {
// Definition of the statement that is to be run by every theory
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasNotifyRestart && d_logicInfo.isTheoryEnabled(THEORY)) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->notifyRestart(); \
}
// notify each theory using the statement above
CVC4_FOR_EACH_THEORY;
}
void TheoryEngine::ppStaticLearn(TNode in, NodeBuilder<>& learned) {
// Definition of the statement that is to be run by every theory
#ifdef CVC4_FOR_EACH_THEORY_STATEMENT
#undef CVC4_FOR_EACH_THEORY_STATEMENT
#endif
#define CVC4_FOR_EACH_THEORY_STATEMENT(THEORY) \
if (theory::TheoryTraits<THEORY>::hasStaticLearning) { \
reinterpret_cast<theory::TheoryTraits<THEORY>::theory_class*>(theoryOf(THEORY))->ppStaticLearn(in, learned); \
}
// static learning for each theory using the statement above
CVC4_FOR_EACH_THEORY;
}
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::Rewriter::shutdown();
d_ppCache.clear();
}
theory::Theory::PPAssertStatus TheoryEngine::solve(TNode literal, SubstitutionMap& substitutionOut) {
TNode atom = literal.getKind() == kind::NOT ? literal[0] : literal;
Trace("theory::solve") << "TheoryEngine::solve(" << literal << "): solving with " << theoryOf(atom)->getId() << endl;
Theory::PPAssertStatus solveStatus = theoryOf(atom)->ppAssert(literal, substitutionOut);
Trace("theory::solve") << "TheoryEngine::solve(" << literal << ") => " << solveStatus << endl;
return solveStatus;
}
// Recursively traverse a term and call the theory rewriter on its sub-terms
Node TheoryEngine::ppTheoryRewrite(TNode term)
{
NodeMap::iterator find = d_ppCache.find(term);
if (find != d_ppCache.end()) {
return (*find).second;
}
unsigned nc = term.getNumChildren();
if (nc == 0) {
return theoryOf(term)->ppRewrite(term);
}
Trace("theory-pp") << "ppTheoryRewrite { " << term << endl;
Node newTerm;
if (theoryOf(term)->ppDontRewriteSubterm(term)) {
newTerm = term;
} else {
NodeBuilder<> newNode(term.getKind());
if (term.getMetaKind() == kind::metakind::PARAMETERIZED) {
newNode << term.getOperator();
}
unsigned i;
for (i = 0; i < nc; ++i) {
newNode << ppTheoryRewrite(term[i]);
}
newTerm = Rewriter::rewrite(Node(newNode));
}
Node newTerm2 = theoryOf(newTerm)->ppRewrite(newTerm);
if (newTerm != newTerm2) {
newTerm = ppTheoryRewrite(Rewriter::rewrite(newTerm2));
}
d_ppCache[term] = newTerm;
Trace("theory-pp")<< "ppTheoryRewrite returning " << newTerm << "}" << endl;
return newTerm;
}
void TheoryEngine::preprocessStart()
{
d_ppCache.clear();
}
struct preprocess_stack_element {
TNode node;
bool children_added;
preprocess_stack_element(TNode node)
: node(node), children_added(false) {}
};/* struct preprocess_stack_element */
Node TheoryEngine::preprocess(TNode assertion) {
Trace("theory::preprocess") << "TheoryEngine::preprocess(" << assertion << ")" << endl;
// Do a topological sort of the subexpressions and substitute them
vector<preprocess_stack_element> toVisit;
toVisit.push_back(assertion);
while (!toVisit.empty())
{
// The current node we are processing
preprocess_stack_element& stackHead = toVisit.back();
TNode current = stackHead.node;
Debug("theory::internal") << "TheoryEngine::preprocess(" << assertion << "): processing " << current << endl;
// If node already in the cache we're done, pop from the stack
NodeMap::iterator find = d_ppCache.find(current);
if (find != d_ppCache.end()) {
toVisit.pop_back();
continue;
}
// If this is an atom, we preprocess its terms with the theory ppRewriter
if (Theory::theoryOf(current) != THEORY_BOOL) {
d_ppCache[current] = ppTheoryRewrite(current);
Assert(Rewriter::rewrite(d_ppCache[current]) == d_ppCache[current]);
continue;
}
// Not yet substituted, so process
if (stackHead.children_added) {
// Children have been processed, so substitute
NodeBuilder<> builder(current.getKind());
if (current.getMetaKind() == kind::metakind::PARAMETERIZED) {
builder << current.getOperator();
}
for (unsigned i = 0; i < current.getNumChildren(); ++ i) {
Assert(d_ppCache.find(current[i]) != d_ppCache.end());
builder << d_ppCache[current[i]];
}
// Mark the substitution and continue
Node result = builder;
if (result != current) {
result = Rewriter::rewrite(result);
}
Debug("theory::internal") << "TheoryEngine::preprocess(" << assertion << "): setting " << current << " -> " << result << endl;
d_ppCache[current] = result;
toVisit.pop_back();
} else {
// Mark that we have added the children if any
if (current.getNumChildren() > 0) {
stackHead.children_added = true;
// We need to add the children
for(TNode::iterator child_it = current.begin(); child_it != current.end(); ++ child_it) {
TNode childNode = *child_it;
NodeMap::iterator childFind = d_ppCache.find(childNode);
if (childFind == d_ppCache.end()) {
toVisit.push_back(childNode);
}
}
} else {
// No children, so we're done
Debug("substitution::internal") << "SubstitutionMap::internalSubstitute(" << assertion << "): setting " << current << " -> " << current << endl;
d_ppCache[current] = current;
toVisit.pop_back();
}
}
}
// Return the substituted version
return d_ppCache[assertion];
}
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" << std::endl;
return false;
}
Trace("theory::assertToTheory") << "TheoryEngine::markPropagation(): marking [" << d_propagationMapTimestamp << "] " << assertion << ", " << toTheoryId << " from " << originalAssertion << ", " << fromTheoryId << std::endl;
// Mark the propagation
d_propagationMap[toAssert] = toExplain;
d_propagationMapTimestamp = d_propagationMapTimestamp + 1;
return true;
}
void TheoryEngine::assertToTheory(TNode assertion, theory::TheoryId toTheoryId, theory::TheoryId fromTheoryId) {
Trace("theory::assertToTheory") << "TheoryEngine::assertToTheory(" << assertion << ", " << toTheoryId << ", " << fromTheoryId << ")" << std::endl;
Assert(toTheoryId != fromTheoryId);
if (d_inConflict) {
return;
}
// If sharing is disabled, things are easy
if (!d_logicInfo.isSharingEnabled()) {
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" << std::endl;
d_inConflict = true;
} else {
return;
}
}
d_propagatedLiterals.push_back(assertion);
}
return;
}
// Polarity of the assertion
bool polarity = assertion.getKind() != kind::NOT;
// Atom of the assertion
TNode atom = polarity ? assertion : assertion[0];
// If sending to the shared terms database, it's also simple
if (toTheoryId == THEORY_BUILTIN) {
Assert(atom.getKind() == kind::EQUAL);
if (markPropagation(assertion, assertion, toTheoryId, fromTheoryId)) {
d_sharedTerms.assertEquality(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, assertion, toTheoryId, fromTheoryId)) {
// We assert it, and we know it's preregistereed coming from the SAT solver directly
theoryOf(toTheoryId)->assertFact(assertion, true);
// 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) {
if (markPropagation(assertion, assertion, 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) {
d_inConflict = true;
}
}
return;
}
// See if it rewrites to true or false directly
Node normalizedLiteral = Rewriter::rewrite(assertion);
if (normalizedLiteral.isConst()) {
if (normalizedLiteral.getConst<bool>()) {
// trivially true, but theories need to share even trivially true facts
// unless of course it is the theory that normalized it
if (Theory::theoryOf(atom) == toTheoryId) {
return;
}
} else {
// Mark the propagation for explanations
if (markPropagation(normalizedLiteral, assertion, toTheoryId, fromTheoryId)) {
// Get the explanation (conflict will figure out where it came from)
conflict(normalizedLiteral, toTheoryId);
} else {
Unreachable();
}
return;
}
}
// Normalize to lhs < rhs if not a sat literal
Assert(atom.getKind() == kind::EQUAL);
Assert(atom[0] != atom[1]);
Node normalizedAtom = atom;
if (!d_propEngine->isSatLiteral(normalizedAtom)) {
Node reverse = atom[1].eqNode(atom[0]);
if (d_propEngine->isSatLiteral(reverse) || atom[0] > atom[1]) {
normalizedAtom = reverse;
}
}
Node normalizedAssertion = polarity ? normalizedAtom : normalizedAtom.notNode();
// Try and assert (note that we assert the non-normalized one)
if (markPropagation(normalizedAssertion, assertion, toTheoryId, fromTheoryId)) {
// Check if has been pre-registered with the theory
bool preregistered = d_propEngine->isSatLiteral(normalizedAssertion) && Theory::theoryOf(normalizedAtom) == toTheoryId;
// Assert away
theoryOf(toTheoryId)->assertFact(normalizedAssertion, preregistered);
d_factsAsserted = true;
}
return;
}
void TheoryEngine::assertFact(TNode literal)
{
Trace("theory") << "TheoryEngine::assertFact(" << literal << ")" << std::endl;
d_propEngine->checkTime();
// 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
if (d_sharedTerms.hasSharedTerms(atom)) {
// Notify the theories the shared terms
SharedTermsDatabase::shared_terms_iterator it = d_sharedTerms.begin(atom);
SharedTermsDatabase::shared_terms_iterator it_end = d_sharedTerms.end(atom);
for (; it != it_end; ++ it) {
TNode term = *it;
Theory::Set theories = d_sharedTerms.getTheoriesToNotify(atom, term);
for (TheoryId id = THEORY_FIRST; id != THEORY_LAST; ++ id) {
if (Theory::setContains(id, theories)) {
theoryOf(id)->addSharedTermInternal(term);
}
}
d_sharedTerms.markNotified(term, theories);
}
}
// 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, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
// Shared terms manager will assert to interested theories directly, as the terms become shared
assertToTheory(literal, /* to */ THEORY_BUILTIN, /* from */ THEORY_SAT_SOLVER);
} else {
// Not an equality, just assert to the appropriate theory
assertToTheory(literal, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
}
} else {
// Assert the fact to the appropriate theory directly
assertToTheory(literal, /* to */ Theory::theoryOf(atom), /* from */ THEORY_SAT_SOLVER);
}
}
bool TheoryEngine::propagate(TNode literal, theory::TheoryId theory) {
Debug("theory::propagate") << "TheoryEngine::propagate(" << literal << ", " << theory << ")" << std::endl;
d_propEngine->checkTime();
if(Dump.isOn("t-propagations")) {
Dump("t-propagations") << CommentCommand("negation of theory propagation: expect valid")
<< QueryCommand(literal.toExpr());
}
if(Dump.isOn("missed-t-propagations")) {
d_hasPropagated.insert(literal);
}
// 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, /* to */ THEORY_SAT_SOLVER, /* from */ theory);
}
if (theory != THEORY_BUILTIN) {
// Assert to the shared terms database
assertToTheory(literal, /* to */ THEORY_BUILTIN, /* from */ theory);
}
} else {
// Just send off to the SAT solver
Assert(d_propEngine->isSatLiteral(literal));
assertToTheory(literal, /* to */ THEORY_SAT_SOLVER, /* from */ theory);
}
return !d_inConflict;
}
void TheoryEngine::propagateAsDecision(TNode literal, theory::TheoryId theory) {
Debug("theory") << "EngineOutputChannel::propagateAsDecision(" << literal << ", " << theory << ")" << std::endl;
d_propEngine->checkTime();
Assert(d_propEngine->isSatLiteral(literal.getKind() == kind::NOT ? literal[0] : literal), "OutputChannel::propagateAsDecision() requires a SAT literal (or negation of one)");
d_decisionRequests.push_back(literal);
}
theory::EqualityStatus TheoryEngine::getEqualityStatus(TNode a, TNode b) {
Assert(a.getType().isComparableTo(b.getType()));
if (d_sharedTerms.isShared(a) && d_sharedTerms.isShared(b)) {
if (d_sharedTerms.areEqual(a,b)) {
return EQUALITY_TRUE_AND_PROPAGATED;
}
else if (d_sharedTerms.areDisequal(a,b)) {
return EQUALITY_FALSE_AND_PROPAGATED;
}
}
return theoryOf(Theory::theoryOf(a.getType()))->getEqualityStatus(a, b);
}
static Node mkExplanation(const std::vector<NodeTheoryPair>& explanation) {
std::set<TNode> all;
for (unsigned i = 0; i < explanation.size(); ++ i) {
Assert(explanation[i].theory == THEORY_SAT_SOLVER);
all.insert(explanation[i].node);
}
if (all.size() == 0) {
// Normalize to true
return NodeManager::currentNM()->mkConst<bool>(true);
}
if (all.size() == 1) {
// All the same, or just one
return explanation[0].node;
}
NodeBuilder<> conjunction(kind::AND);
std::set<TNode>::const_iterator it = all.begin();
std::set<TNode>::const_iterator it_end = all.end();
while (it != it_end) {
conjunction << *it;
++ it;
}
return conjunction;
}
Node TheoryEngine::getExplanation(TNode node) {
Debug("theory::explain") << "TheoryEngine::getExplanation(" << node << "): current propagation index = " << d_propagationMapTimestamp << std::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()) {
Node explanation = theoryOf(atom)->explain(node);
Debug("theory::explain") << "TheoryEngine::getExplanation(" << node << ") => " << explanation << std::endl;
return explanation;
}
// Initial thing to explain
NodeTheoryPair toExplain(node, THEORY_SAT_SOLVER, d_propagationMapTimestamp);
Assert(d_propagationMap.find(toExplain) != d_propagationMap.end());
// Create the workplace for explanations
std::vector<NodeTheoryPair> explanationVector;
explanationVector.push_back(d_propagationMap[toExplain]);
// Process the explanation
getExplanation(explanationVector);
Node explanation = mkExplanation(explanationVector);
Debug("theory::explain") << "TheoryEngine::getExplanation(" << node << ") => " << explanation << std::endl;
return explanation;
}
theory::LemmaStatus TheoryEngine::lemma(TNode node, bool negated, bool removable) {
if(Dump.isOn("t-lemmas")) {
Dump("t-lemmas") << CommentCommand("theory lemma: expect valid")
<< QueryCommand(node.toExpr());
}
// Share with other portfolio threads
if(Options::current()->lemmaOutputChannel != NULL) {
Options::current()->lemmaOutputChannel->notifyNewLemma(node.toExpr());
}
// Remove the ITEs
std::vector<Node> additionalLemmas;
IteSkolemMap iteSkolemMap;
additionalLemmas.push_back(node);
RemoveITE::run(additionalLemmas, iteSkolemMap);
additionalLemmas[0] = theory::Rewriter::rewrite(additionalLemmas[0]);
// assert to prop engine
d_propEngine->assertLemma(additionalLemmas[0], negated, removable);
for (unsigned i = 1; i < additionalLemmas.size(); ++ i) {
additionalLemmas[i] = theory::Rewriter::rewrite(additionalLemmas[i]);
d_propEngine->assertLemma(additionalLemmas[i], false, removable);
}
// WARNING: Below this point don't assume additionalLemmas[0] to be not negated.
// WARNING: Below this point don't assume additionalLemmas[0] to be not negated.
if(negated) {
// Can't we just get rid of passing around this 'negated' stuff?
// Is it that hard for the propEngine to figure that out itself?
// (I like the use of triple negation <evil laugh>.) --K
additionalLemmas[0] = additionalLemmas[0].notNode();
negated = false;
}
// WARNING: Below this point don't assume additionalLemmas[0] to be not negated.
// WARNING: Below this point don't assume additionalLemmas[0] to be not negated.
// assert to decision engine
if(!removable) {
d_decisionEngine->addAssertions(additionalLemmas, 1, iteSkolemMap);
}
// Mark that we added some lemmas
d_lemmasAdded = true;
// Lemma analysis isn't online yet; this lemma may only live for this
// user level.
return theory::LemmaStatus(additionalLemmas[0], d_userContext->getLevel());
}
void TheoryEngine::conflict(TNode conflict, TheoryId theoryId) {
Debug("theory::conflict") << "TheoryEngine::conflict(" << conflict << ", " << theoryId << ")" << std::endl;
// Mark that we are in conflict
d_inConflict = true;
if(Dump.isOn("t-conflicts")) {
Dump("t-conflicts") << CommentCommand("theory conflict: expect unsat")
<< CheckSatCommand(conflict.toExpr());
}
// In the multiple-theories case, we need to reconstruct the conflict
if (d_logicInfo.isSharingEnabled()) {
// Create the workplace for explanations
std::vector<NodeTheoryPair> explanationVector;
explanationVector.push_back(NodeTheoryPair(conflict, theoryId, d_propagationMapTimestamp));
// Process the explanation
getExplanation(explanationVector);
Node fullConflict = mkExplanation(explanationVector);
Debug("theory::conflict") << "TheoryEngine::conflict(" << conflict << ", " << theoryId << "): full = " << fullConflict << std::endl;
Assert(properConflict(fullConflict));
lemma(fullConflict, true, true);
} else {
// When only one theory, the conflict should need no processing
Assert(properConflict(conflict));
lemma(conflict, true, true);
}
}
Node TheoryEngine::ppSimpITE(TNode assertion)
{
Node result = d_iteSimplifier.simpITE(assertion);
result = d_iteSimplifier.simplifyWithCare(Rewriter::rewrite(result));
result = Rewriter::rewrite(result);
return result;
}
void TheoryEngine::getExplanation(std::vector<NodeTheoryPair>& explanationVector)
{
Assert(explanationVector.size() > 0);
unsigned i = 0; // Index of the current literal we are processing
unsigned j = 0; // Index of the last literal we are keeping
while (i < explanationVector.size()) {
// Get the current literal to explain
NodeTheoryPair toExplain = explanationVector[i];
Debug("theory::explain") << "TheoryEngine::explain(): processing [" << toExplain.timestamp << "] " << toExplain.node << " sent from " << toExplain.theory << std::endl;
// If a treu constant or a negation of a false constant we can ignore it
if (toExplain.node.isConst() && toExplain.node.getConst<bool>()) {
++ i;
continue;
}
if (toExplain.node.getKind() == kind::NOT && toExplain.node[0].isConst() && !toExplain.node[0].getConst<bool>()) {
++ i;
continue;
}
// If from the SAT solver, keep it
if (toExplain.theory == THEORY_SAT_SOLVER) {
explanationVector[j++] = explanationVector[i++];
continue;
}
// If an and, expand it
if (toExplain.node.getKind() == kind::AND) {
Debug("theory::explain") << "TheoryEngine::explain(): expanding " << toExplain.node << " got from " << toExplain.theory << std::endl;
for (unsigned k = 0; k < toExplain.node.getNumChildren(); ++ k) {
NodeTheoryPair newExplain(toExplain.node[k], toExplain.theory, toExplain.timestamp);
explanationVector.push_back(newExplain);
}
++ 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()) {
// There is some propagation, check if its a timely one
if ((*find).second.timestamp < toExplain.timestamp) {
explanationVector.push_back((*find).second);
++ i;
continue;
}
}
// It was produced by the theory, so ask for an explanation
Node explanation;
if (toExplain.theory == THEORY_BUILTIN) {
explanation = d_sharedTerms.explain(toExplain.node);
} else {
explanation = theoryOf(toExplain.theory)->explain(toExplain.node);
}
Debug("theory::explain") << "TheoryEngine::explain(): got explanation " << explanation << " got from " << toExplain.theory << std::endl;
Assert(explanation != toExplain.node, "wasn't sent to you, so why are you explaining it trivially");
// Mark the explanation
NodeTheoryPair newExplain(explanation, toExplain.theory, toExplain.timestamp);
explanationVector.push_back(newExplain);
++ i;
}
// Keep only the relevant literals
explanationVector.resize(j);
}
void TheoryEngine::ppUnconstrainedSimp(vector<Node>& assertions)
{
d_unconstrainedSimp.processAssertions(assertions);
}
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