1 /********************* */
2 /*! \file bv_subtheory_core.cpp
4 ** Top contributors (to current version):
5 ** Liana Hadarean, Andrew Reynolds, Tim King
6 ** This file is part of the CVC4 project.
7 ** Copyright (c) 2009-2017 by the authors listed in the file AUTHORS
8 ** in the top-level source directory) and their institutional affiliations.
9 ** All rights reserved. See the file COPYING in the top-level source
10 ** directory for licensing information.\endverbatim
12 ** \brief Algebraic solver.
17 #include "theory/bv/bv_subtheory_core.h"
19 #include "options/bv_options.h"
20 #include "options/smt_options.h"
21 #include "smt/smt_statistics_registry.h"
22 #include "theory/bv/slicer.h"
23 #include "theory/bv/theory_bv.h"
24 #include "theory/bv/theory_bv_utils.h"
25 #include "theory/theory_model.h"
29 using namespace CVC4::context
;
30 using namespace CVC4::theory
;
31 using namespace CVC4::theory::bv
;
32 using namespace CVC4::theory::bv::utils
;
34 CoreSolver::CoreSolver(context::Context
* c
, TheoryBV
* bv
)
35 : SubtheorySolver(c
, bv
),
37 d_equalityEngine(d_notify
, c
, "theory::bv::TheoryBV", true),
38 d_slicer(new Slicer()),
39 d_isComplete(c
, true),
42 d_preregisterCalled(false),
46 // The kinds we are treating as function application in congruence
47 d_equalityEngine
.addFunctionKind(kind::BITVECTOR_CONCAT
, true);
48 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_AND);
49 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_OR);
50 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_XOR);
51 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_NOT);
52 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_NAND);
53 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_NOR);
54 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_XNOR);
55 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_COMP);
56 d_equalityEngine
.addFunctionKind(kind::BITVECTOR_MULT
, true);
57 d_equalityEngine
.addFunctionKind(kind::BITVECTOR_PLUS
, true);
58 d_equalityEngine
.addFunctionKind(kind::BITVECTOR_EXTRACT
, true);
59 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SUB);
60 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_NEG);
61 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_UDIV);
62 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_UREM);
63 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SDIV);
64 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SREM);
65 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SMOD);
66 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SHL);
67 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_LSHR);
68 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_ASHR);
69 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_ULT);
70 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_ULE);
71 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_UGT);
72 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_UGE);
73 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SLT);
74 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SLE);
75 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SGT);
76 // d_equalityEngine.addFunctionKind(kind::BITVECTOR_SGE);
77 d_equalityEngine
.addFunctionKind(kind::BITVECTOR_TO_NAT
);
78 d_equalityEngine
.addFunctionKind(kind::INT_TO_BITVECTOR
);
81 CoreSolver::~CoreSolver() {
84 void CoreSolver::setMasterEqualityEngine(eq::EqualityEngine
* eq
) {
85 d_equalityEngine
.setMasterEqualityEngine(eq
);
88 void CoreSolver::enableSlicer() {
89 AlwaysAssert (!d_preregisterCalled
);
91 d_statistics
.d_slicerEnabled
.setData(true);
94 void CoreSolver::preRegister(TNode node
) {
95 d_preregisterCalled
= true;
96 if (node
.getKind() == kind::EQUAL
) {
97 d_equalityEngine
.addTriggerEquality(node
);
99 d_slicer
->processEquality(node
);
100 AlwaysAssert(!d_checkCalled
);
103 d_equalityEngine
.addTerm(node
);
108 void CoreSolver::explain(TNode literal
, std::vector
<TNode
>& assumptions
) {
109 bool polarity
= literal
.getKind() != kind::NOT
;
110 TNode atom
= polarity
? literal
: literal
[0];
111 if (atom
.getKind() == kind::EQUAL
) {
112 d_equalityEngine
.explainEquality(atom
[0], atom
[1], polarity
, assumptions
);
114 d_equalityEngine
.explainPredicate(atom
, polarity
, assumptions
);
118 Node
CoreSolver::getBaseDecomposition(TNode a
) {
119 std::vector
<Node
> a_decomp
;
120 d_slicer
->getBaseDecomposition(a
, a_decomp
);
121 Node new_a
= utils::mkConcat(a_decomp
);
122 Debug("bv-slicer") << "CoreSolver::getBaseDecomposition " << a
<<" => " << new_a
<< "\n";
126 bool CoreSolver::decomposeFact(TNode fact
) {
127 Debug("bv-slicer") << "CoreSolver::decomposeFact fact=" << fact
<< endl
;
128 // FIXME: are this the right things to assert?
129 // assert decompositions since the equality engine does not know the semantics of
131 // a == a_1 concat ... concat a_k
132 // b == b_1 concat ... concat b_k
133 TNode eq
= fact
.getKind() == kind::NOT
? fact
[0] : fact
;
137 Node new_a
= getBaseDecomposition(a
);
138 Node new_b
= getBaseDecomposition(b
);
140 Assert (utils::getSize(new_a
) == utils::getSize(new_b
) &&
141 utils::getSize(new_a
) == utils::getSize(a
));
143 NodeManager
* nm
= NodeManager::currentNM();
144 Node a_eq_new_a
= nm
->mkNode(kind::EQUAL
, a
, new_a
);
145 Node b_eq_new_b
= nm
->mkNode(kind::EQUAL
, b
, new_b
);
148 ok
= assertFactToEqualityEngine(a_eq_new_a
, utils::mkTrue());
149 if (!ok
) return false;
150 ok
= assertFactToEqualityEngine(b_eq_new_b
, utils::mkTrue());
151 if (!ok
) return false;
152 ok
= assertFactToEqualityEngine(fact
, fact
);
153 if (!ok
) return false;
155 if (fact
.getKind() == kind::EQUAL
) {
156 // assert the individual equalities as well
158 if (new_a
.getKind() == kind::BITVECTOR_CONCAT
&&
159 new_b
.getKind() == kind::BITVECTOR_CONCAT
) {
161 Assert (new_a
.getNumChildren() == new_b
.getNumChildren());
162 for (unsigned i
= 0; i
< new_a
.getNumChildren(); ++i
) {
163 Node eq_i
= nm
->mkNode(kind::EQUAL
, new_a
[i
], new_b
[i
]);
164 ok
= assertFactToEqualityEngine(eq_i
, fact
);
165 if (!ok
) return false;
172 bool CoreSolver::check(Theory::Effort e
) {
173 Trace("bitvector::core") << "CoreSolver::check \n";
175 d_bv
->spendResource(options::theoryCheckStep());
177 d_checkCalled
= true;
178 Assert (!d_bv
->inConflict());
179 ++(d_statistics
.d_numCallstoCheck
);
181 std::vector
<Node
> core_eqs
;
183 // slicer does not deal with cardinality constraints yet
185 d_isComplete
= false;
189 if (d_isComplete
&& !isCompleteForTerm(fact
, seen
)) {
190 d_isComplete
= false;
193 // only reason about equalities
194 if (fact
.getKind() == kind::EQUAL
|| (fact
.getKind() == kind::NOT
&& fact
[0].getKind() == kind::EQUAL
)) {
196 ok
= decomposeFact(fact
);
198 ok
= assertFactToEqualityEngine(fact
, fact
);
201 ok
= assertFactToEqualityEngine(fact
, fact
);
207 if (Theory::fullEffort(e
) && isComplete()) {
214 void CoreSolver::buildModel() {
215 Debug("bv-core") << "CoreSolver::buildModel() \n";
216 d_modelValues
.clear();
218 TNodeSet constants_in_eq_engine
;
219 // collect constants in equality engine
220 eq::EqClassesIterator eqcs_i
= eq::EqClassesIterator(&d_equalityEngine
);
221 while (!eqcs_i
.isFinished()) {
222 TNode repr
= *eqcs_i
;
223 if (repr
.getKind() == kind::CONST_BITVECTOR
) {
224 // must check if it's just the constant
225 eq::EqClassIterator
it(repr
, &d_equalityEngine
);
226 if (!(++it
).isFinished() || true) {
227 constants
.insert(repr
);
228 constants_in_eq_engine
.insert(repr
);
234 // build repr to value map
236 eqcs_i
= eq::EqClassesIterator(&d_equalityEngine
);
237 while (!eqcs_i
.isFinished()) {
238 TNode repr
= *eqcs_i
;
242 repr
.getKind() != kind::CONST_BITVECTOR
&&
243 !d_bv
->isSharedTerm(repr
)) {
247 TypeNode type
= repr
.getType();
248 if (type
.isBitVector() && repr
.getKind()!= kind::CONST_BITVECTOR
) {
249 Debug("bv-core-model") << " processing " << repr
<<"\n";
250 // we need to assign a value for it
251 TypeEnumerator
te(type
);
256 // Debug("bv-core-model") << " trying value " << val << "\n";
257 // Debug("bv-core-model") << " is in set? " << constants.count(val) << "\n";
258 // Debug("bv-core-model") << " enumerator done? " << te.isFinished() << "\n";
259 } while (constants
.count(val
) != 0 && !(te
.isFinished()));
261 if (te
.isFinished() && constants
.count(val
) != 0) {
262 // if we cannot enumerate anymore values we just return the lemma stating that
263 // at least two of the representatives are equal.
264 std::vector
<TNode
> representatives
;
265 representatives
.push_back(repr
);
267 for (TNodeSet::const_iterator it
= constants_in_eq_engine
.begin();
268 it
!= constants_in_eq_engine
.end(); ++it
) {
269 TNode constant
= *it
;
270 if (utils::getSize(constant
) == utils::getSize(repr
)) {
271 representatives
.push_back(constant
);
274 for (ModelValue::const_iterator it
= d_modelValues
.begin(); it
!= d_modelValues
.end(); ++it
) {
275 representatives
.push_back(it
->first
);
277 std::vector
<Node
> equalities
;
278 for (unsigned i
= 0; i
< representatives
.size(); ++i
) {
279 for (unsigned j
= i
+ 1; j
< representatives
.size(); ++j
) {
280 TNode a
= representatives
[i
];
281 TNode b
= representatives
[j
];
282 if (a
.getKind() == kind::CONST_BITVECTOR
&&
283 b
.getKind() == kind::CONST_BITVECTOR
) {
287 if (utils::getSize(a
) == utils::getSize(b
)) {
288 equalities
.push_back(utils::mkNode(kind::EQUAL
, a
, b
));
292 // better off letting the SAT solver split on values
293 if (equalities
.size() > d_lemmaThreshold
) {
294 d_isComplete
= false;
298 Node lemma
= utils::mkOr(equalities
);
300 Debug("bv-core") << " lemma: " << lemma
<< "\n";
304 Debug("bv-core-model") << " " << repr
<< " => " << val
<<"\n" ;
305 constants
.insert(val
);
306 d_modelValues
[repr
] = val
;
311 bool CoreSolver::assertFactToEqualityEngine(TNode fact
, TNode reason
) {
312 // Notify the equality engine
313 if (!d_bv
->inConflict() && (!d_bv
->wasPropagatedBySubtheory(fact
) || d_bv
->getPropagatingSubtheory(fact
) != SUB_CORE
)) {
314 Debug("bv-slicer-eq") << "CoreSolver::assertFactToEqualityEngine fact=" << fact
<< endl
;
315 // Debug("bv-slicer-eq") << " reason=" << reason << endl;
316 bool negated
= fact
.getKind() == kind::NOT
;
317 TNode predicate
= negated
? fact
[0] : fact
;
318 if (predicate
.getKind() == kind::EQUAL
) {
321 d_equalityEngine
.assertEquality(predicate
, false, reason
);
324 d_equalityEngine
.assertEquality(predicate
, true, reason
);
327 // Adding predicate if the congruence over it is turned on
328 if (d_equalityEngine
.isFunctionKind(predicate
.getKind())) {
329 d_equalityEngine
.assertPredicate(predicate
, !negated
, reason
);
334 // checking for a conflict
335 if (d_bv
->inConflict()) {
341 bool CoreSolver::NotifyClass::eqNotifyTriggerEquality(TNode equality
, bool value
) {
342 Debug("bitvector::core") << "NotifyClass::eqNotifyTriggerEquality(" << equality
<< ", " << (value
? "true" : "false" )<< ")" << std::endl
;
344 return d_solver
.storePropagation(equality
);
346 return d_solver
.storePropagation(equality
.notNode());
350 bool CoreSolver::NotifyClass::eqNotifyTriggerPredicate(TNode predicate
, bool value
) {
351 Debug("bitvector::core") << "NotifyClass::eqNotifyTriggerPredicate(" << predicate
<< ", " << (value
? "true" : "false" ) << ")" << std::endl
;
353 return d_solver
.storePropagation(predicate
);
355 return d_solver
.storePropagation(predicate
.notNode());
359 bool CoreSolver::NotifyClass::eqNotifyTriggerTermEquality(TheoryId tag
, TNode t1
, TNode t2
, bool value
) {
360 Debug("bitvector::core") << "NotifyClass::eqNotifyTriggerTermMerge(" << t1
<< ", " << t2
<< ")" << std::endl
;
362 return d_solver
.storePropagation(t1
.eqNode(t2
));
364 return d_solver
.storePropagation(t1
.eqNode(t2
).notNode());
368 void CoreSolver::NotifyClass::eqNotifyConstantTermMerge(TNode t1
, TNode t2
) {
369 d_solver
.conflict(t1
, t2
);
372 void CoreSolver::NotifyClass::eqNotifyNewClass(TNode t
) {
373 d_solver
.eqNotifyNewClass( t
);
376 bool CoreSolver::storePropagation(TNode literal
) {
377 return d_bv
->storePropagation(literal
, SUB_CORE
);
380 void CoreSolver::conflict(TNode a
, TNode b
) {
381 std::vector
<TNode
> assumptions
;
382 d_equalityEngine
.explainEquality(a
, b
, true, assumptions
);
383 Node conflict
= flattenAnd(assumptions
);
384 d_bv
->setConflict(conflict
);
387 void CoreSolver::eqNotifyNewClass(TNode t
) {
388 Assert( d_bv
->getExtTheory()!=NULL
);
389 d_bv
->getExtTheory()->registerTerm( t
);
392 bool CoreSolver::isCompleteForTerm(TNode term
, TNodeBoolMap
& seen
) {
394 return utils::isCoreTerm(term
, seen
);
396 return utils::isEqualityTerm(term
, seen
);
399 void CoreSolver::collectModelInfo(TheoryModel
* m
, bool fullModel
) {
403 if (Debug
.isOn("bitvector-model")) {
404 context::CDQueue
<Node
>::const_iterator it
= d_assertionQueue
.begin();
405 for (; it
!= d_assertionQueue
.end(); ++it
) {
406 Debug("bitvector-model") << "CoreSolver::collectModelInfo (assert "
411 d_bv
->computeRelevantTerms(termSet
);
412 m
->assertEqualityEngine(&d_equalityEngine
, &termSet
);
414 Debug("bitvector-model") << "CoreSolver::collectModelInfo complete.";
415 for (ModelValue::const_iterator it
= d_modelValues
.begin(); it
!= d_modelValues
.end(); ++it
) {
418 Debug("bitvector-model") << "CoreSolver::collectModelInfo modelValues "
419 << a
<< " => " << b
<<")\n";
420 m
->assertEquality(a
, b
, true);
425 Node
CoreSolver::getModelValue(TNode var
) {
426 // we don't need to evaluate bv expressions and only look at variable values
427 // because this only gets called when the core theory is complete (i.e. no other bv
428 // function symbols are currently asserted)
429 Assert (d_slicer
->isCoreTerm(var
));
431 Debug("bitvector-model") << "CoreSolver::getModelValue (" << var
<<")";
432 Assert (isComplete());
433 TNode repr
= d_equalityEngine
.getRepresentative(var
);
434 Node result
= Node();
435 if (repr
.getKind() == kind::CONST_BITVECTOR
) {
437 } else if (d_modelValues
.find(repr
) == d_modelValues
.end()) {
438 // it may be a shared term that never gets asserted
439 // result is just Null
440 Assert(d_bv
->isSharedTerm(var
));
442 result
= d_modelValues
[repr
];
444 Debug("bitvector-model") << " => " << result
<<"\n";
448 CoreSolver::Statistics::Statistics()
449 : d_numCallstoCheck("theory::bv::CoreSolver::NumCallsToCheck", 0)
450 , d_slicerEnabled("theory::bv::CoreSolver::SlicerEnabled", false)
452 smtStatisticsRegistry()->registerStat(&d_numCallstoCheck
);
453 smtStatisticsRegistry()->registerStat(&d_slicerEnabled
);
455 CoreSolver::Statistics::~Statistics() {
456 smtStatisticsRegistry()->unregisterStat(&d_numCallstoCheck
);
457 smtStatisticsRegistry()->unregisterStat(&d_slicerEnabled
);