1 /********************* */
2 /*! \file theory_engine.h
4 ** Top contributors (to current version):
5 ** Dejan Jovanovic, Andrew Reynolds, Morgan Deters
6 ** This file is part of the CVC4 project.
7 ** Copyright (c) 2009-2020 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 The theory engine
17 #include "cvc4_private.h"
19 #ifndef CVC4__THEORY_ENGINE_H
20 #define CVC4__THEORY_ENGINE_H
25 #include <unordered_map>
29 #include "base/check.h"
30 #include "context/cdhashset.h"
31 #include "expr/node.h"
32 #include "options/options.h"
33 #include "options/smt_options.h"
34 #include "options/theory_options.h"
35 #include "prop/prop_engine.h"
36 #include "smt/command.h"
37 #include "theory/atom_requests.h"
38 #include "theory/engine_output_channel.h"
39 #include "theory/interrupted.h"
40 #include "theory/rewriter.h"
41 #include "theory/sort_inference.h"
42 #include "theory/substitutions.h"
43 #include "theory/term_registration_visitor.h"
44 #include "theory/theory.h"
45 #include "theory/theory_preprocessor.h"
46 #include "theory/uf/equality_engine.h"
47 #include "theory/valuation.h"
48 #include "util/hash.h"
49 #include "util/resource_manager.h"
50 #include "util/statistics_registry.h"
51 #include "util/unsafe_interrupt_exception.h"
55 class ResourceManager
;
56 class TheoryEngineProofGenerator
;
59 * A pair of a theory and a node. This is used to mark the flow of
60 * propagations between theories.
62 struct NodeTheoryPair
{
64 theory::TheoryId d_theory
;
66 NodeTheoryPair(TNode n
, theory::TheoryId t
, size_t ts
= 0)
67 : d_node(n
), d_theory(t
), d_timestamp(ts
)
70 NodeTheoryPair() : d_theory(theory::THEORY_LAST
), d_timestamp() {}
71 // Comparison doesn't take into account the timestamp
72 bool operator == (const NodeTheoryPair
& pair
) const {
73 return d_node
== pair
.d_node
&& d_theory
== pair
.d_theory
;
75 };/* struct NodeTheoryPair */
77 struct NodeTheoryPairHashFunction
{
78 NodeHashFunction hashFunction
;
79 // Hash doesn't take into account the timestamp
80 size_t operator()(const NodeTheoryPair
& pair
) const {
81 uint64_t hash
= fnv1a::fnv1a_64(NodeHashFunction()(pair
.d_node
));
82 return static_cast<size_t>(fnv1a::fnv1a_64(pair
.d_theory
, hash
));
84 };/* struct NodeTheoryPairHashFunction */
87 /* Forward declarations */
90 class CombinationEngine
;
91 class DecisionManager
;
92 class RelevanceManager
;
98 class EntailmentCheckParameters
;
99 class EntailmentCheckSideEffects
;
100 }/* CVC4::theory namespace */
102 class RemoveTermFormulas
;
105 * This is essentially an abstraction for a collection of theories. A
106 * TheoryEngine provides services to a PropEngine, making various
107 * T-solvers look like a single unit to the propositional part of
112 /** Shared terms database can use the internals notify the theories */
113 friend class SharedTermsDatabase
;
114 friend class theory::CombinationEngine
;
115 friend class theory::EngineOutputChannel
;
116 friend class theory::CombinationEngine
;
118 /** Associated PropEngine engine */
119 prop::PropEngine
* d_propEngine
;
122 context::Context
* d_context
;
124 /** Our user context */
125 context::UserContext
* d_userContext
;
128 * A table of from theory IDs to theory pointers. Never use this table
129 * directly, use theoryOf() instead.
131 theory::Theory
* d_theoryTable
[theory::THEORY_LAST
];
134 * A collection of theories that are "active" for the current run.
135 * This set is provided by the user (as a logic string, say, in SMT-LIBv2
136 * format input), or else by default it's all-inclusive. This is important
137 * because we can optimize for single-theory runs (no sharing), can reduce
138 * the cost of walking the DAG on registration, etc.
140 const LogicInfo
& d_logicInfo
;
142 //--------------------------------- new proofs
143 /** Proof node manager used by this theory engine, if proofs are enabled */
144 ProofNodeManager
* d_pnm
;
145 /** The lazy proof object
147 * This stores instructions for how to construct proofs for all theory lemmas.
149 std::shared_ptr
<LazyCDProof
> d_lazyProof
;
150 /** The proof generator */
151 std::shared_ptr
<TheoryEngineProofGenerator
> d_tepg
;
152 //--------------------------------- end new proofs
155 * The database of shared terms.
157 SharedTermsDatabase d_sharedTerms
;
159 /** The combination manager we are using */
160 std::unique_ptr
<theory::CombinationEngine
> d_tc
;
162 * The quantifiers engine
164 theory::QuantifiersEngine
* d_quantEngine
;
166 * The decision manager
168 std::unique_ptr
<theory::DecisionManager
> d_decManager
;
169 /** The relevance manager */
170 std::unique_ptr
<theory::RelevanceManager
> d_relManager
;
172 /** Default visitor for pre-registration */
173 PreRegisterVisitor d_preRegistrationVisitor
;
175 /** Visitor for collecting shared terms */
176 SharedTermsVisitor d_sharedTermsVisitor
;
178 /** are we in eager model building mode? (see setEagerModelBuilding). */
179 bool d_eager_model_building
;
181 typedef std::unordered_map
<Node
, Node
, NodeHashFunction
> NodeMap
;
182 typedef std::unordered_map
<TNode
, Node
, TNodeHashFunction
> TNodeMap
;
185 * Used for "missed-t-propagations" dumping mode only. A set of all
186 * theory-propagable literals.
188 context::CDList
<TNode
> d_possiblePropagations
;
191 * Used for "missed-t-propagations" dumping mode only. A
192 * context-dependent set of those theory-propagable literals that
193 * have been propagated.
195 context::CDHashSet
<Node
, NodeHashFunction
> d_hasPropagated
;
198 * Output channels for individual theories.
200 theory::EngineOutputChannel
* d_theoryOut
[theory::THEORY_LAST
];
203 * Are we in conflict.
205 context::CDO
<bool> d_inConflict
;
208 * Are we in "SAT mode"? In this state, the user can query for the model.
209 * This corresponds to the state in Figure 4.1, page 52 of the SMT-LIB
210 * standard, version 2.6.
215 * Called by the theories to notify of a conflict.
217 * @param conflict The trust node containing the conflict and its proof
218 * generator (if it exists),
219 * @param theoryId The theory that sent the conflict
221 void conflict(theory::TrustNode conflict
, theory::TheoryId theoryId
);
224 * Debugging flag to ensure that shutdown() is called before the
230 * True if a theory has notified us of incompleteness (at this
231 * context level or below).
233 context::CDO
<bool> d_incomplete
;
236 * Called by the theories to notify that the current branch is incomplete.
238 void setIncomplete(theory::TheoryId theory
) {
243 * Mapping of propagations from recievers to senders.
245 typedef context::CDHashMap
<NodeTheoryPair
, NodeTheoryPair
, NodeTheoryPairHashFunction
> PropagationMap
;
246 PropagationMap d_propagationMap
;
249 * Timestamp of propagations
251 context::CDO
<size_t> d_propagationMapTimestamp
;
254 * Literals that are propagated by the theory. Note that these are TNodes.
255 * The theory can only propagate nodes that have an assigned literal in the
256 * SAT solver and are hence referenced in the SAT solver.
258 context::CDList
<TNode
> d_propagatedLiterals
;
261 * The index of the next literal to be propagated by a theory.
263 context::CDO
<unsigned> d_propagatedLiteralsIndex
;
266 * Called by the output channel to propagate literals and facts
267 * @return false if immediate conflict
269 bool propagate(TNode literal
, theory::TheoryId theory
);
272 * Internal method to call the propagation routines and collect the
273 * propagated literals.
275 void propagate(theory::Theory::Effort effort
);
278 * A variable to mark if we added any lemmas.
283 * A variable to mark if the OutputChannel was "used" by any theory
284 * since the start of the last check. If it has been, we require
285 * a FULL_EFFORT check before exiting and reporting SAT.
287 * See the documentation for the needCheck() function, below.
289 bool d_outputChannelUsed
;
291 /** Atom requests from lemmas */
292 AtomRequests d_atomRequests
;
295 * Adds a new lemma, returning its status.
296 * @param node the lemma
297 * @param p the properties of the lemma.
298 * @param atomsTo the theory that atoms of the lemma should be sent to
299 * @param from the theory that sent the lemma
300 * @return a lemma status, containing the lemma and context information
301 * about when it was sent.
303 theory::LemmaStatus
lemma(theory::TrustNode node
,
304 theory::LemmaProperty p
,
305 theory::TheoryId atomsTo
= theory::THEORY_LAST
,
306 theory::TheoryId from
= theory::THEORY_LAST
);
308 /** Enusre that the given atoms are send to the given theory */
309 void ensureLemmaAtoms(const std::vector
<TNode
>& atoms
, theory::TheoryId theory
);
311 /** sort inference module */
312 SortInference d_sortInfer
;
314 /** The theory preprocessor */
315 theory::TheoryPreprocessor d_tpp
;
317 /** Time spent in theory combination */
318 TimerStat d_combineTheoriesTime
;
323 /** Whether we were just interrupted (or not) */
325 ResourceManager
* d_resourceManager
;
328 /** Constructs a theory engine */
329 TheoryEngine(context::Context
* context
,
330 context::UserContext
* userContext
,
332 RemoveTermFormulas
& iteRemover
,
333 const LogicInfo
& logic
);
335 /** Destroys a theory engine */
340 /** "Spend" a resource during a search or preprocessing.*/
341 void spendResource(ResourceManager::Resource r
);
344 * Adds a theory. Only one theory per TheoryId can be present, so if
345 * there is another theory it will be deleted.
347 template <class TheoryClass
>
348 inline void addTheory(theory::TheoryId theoryId
)
350 Assert(d_theoryTable
[theoryId
] == NULL
&& d_theoryOut
[theoryId
] == NULL
);
351 d_theoryOut
[theoryId
] = new theory::EngineOutputChannel(this, theoryId
);
352 d_theoryTable
[theoryId
] = new TheoryClass(d_context
,
354 *d_theoryOut
[theoryId
],
355 theory::Valuation(this),
358 theory::Rewriter::registerTheoryRewriter(
359 theoryId
, d_theoryTable
[theoryId
]->getTheoryRewriter());
362 void setPropEngine(prop::PropEngine
* propEngine
)
364 d_propEngine
= propEngine
;
368 * Called when all initialization of options/logic is done, after theory
369 * objects have been created.
371 * This initializes the quantifiers engine, the "official" equality engines
372 * of each theory as required, and the model and model builder utilities.
377 * Get a pointer to the underlying propositional engine.
379 inline prop::PropEngine
* getPropEngine() const {
384 * Get a pointer to the underlying sat context.
386 context::Context
* getSatContext() const { return d_context
; }
389 * Get a pointer to the underlying user context.
391 context::UserContext
* getUserContext() const { return d_userContext
; }
394 * Get a pointer to the underlying quantifiers engine.
396 theory::QuantifiersEngine
* getQuantifiersEngine() const {
397 return d_quantEngine
;
400 * Get a pointer to the underlying decision manager.
402 theory::DecisionManager
* getDecisionManager() const
404 return d_decManager
.get();
409 * Queue of nodes for pre-registration.
411 std::queue
<TNode
> d_preregisterQueue
;
414 * Boolean flag denoting we are in pre-registration.
416 bool d_inPreregister
;
419 * Did the theories get any new facts since the last time we called
422 context::CDO
<bool> d_factsAsserted
;
425 * Assert the formula to the given theory.
426 * @param assertion the assertion to send (not necesserily normalized)
427 * @param original the assertion as it was sent in from the propagating theory
428 * @param toTheoryId the theory to assert to
429 * @param fromTheoryId the theory that sent it
431 void assertToTheory(TNode assertion
, TNode originalAssertion
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
434 * Marks a theory propagation from a theory to a theory where a
435 * theory could be the THEORY_SAT_SOLVER for literals coming from
436 * or being propagated to the SAT solver. If the receiving theory
437 * already recieved the literal, the method returns false, otherwise
440 * @param assertion the normalized assertion being sent
441 * @param originalAssertion the actual assertion that was sent
442 * @param toTheoryId the theory that is on the receiving end
443 * @param fromTheoryId the theory that sent the assertion
444 * @return true if a new assertion, false if theory already got it
446 bool markPropagation(TNode assertion
, TNode originalAssertions
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
449 * Computes the explanation by traversing the propagation graph and
450 * asking relevant theories to explain the propagations. Initially
451 * the explanation vector should contain only the element (node, theory)
452 * where the node is the one to be explained, and the theory is the
453 * theory that sent the literal.
455 theory::TrustNode
getExplanation(
456 std::vector
<NodeTheoryPair
>& explanationVector
);
458 /** Are proofs enabled? */
459 bool isProofEnabled() const;
463 * Signal the start of a new round of assertion preprocessing
465 void preprocessStart();
468 * Runs theory specific preprocessing on the non-Boolean parts of
469 * the formula. This is only called on input assertions, after ITEs
472 Node
preprocess(TNode node
);
474 /** Notify (preprocessed) assertions. */
475 void notifyPreprocessedAssertions(const std::vector
<Node
>& assertions
);
477 /** Return whether or not we are incomplete (in the current context). */
478 inline bool isIncomplete() const { return d_incomplete
; }
481 * Returns true if we need another round of checking. If this
482 * returns true, check(FULL_EFFORT) _must_ be called by the
483 * propositional layer before reporting SAT.
485 * This is especially necessary for incomplete theories that lazily
486 * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
487 * outputing quantifier instantiations). In such a case, a lemma can
488 * be asserted that is simplified away (perhaps it's already true).
489 * However, we must maintain the invariant that, if a theory uses the
490 * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
491 * be performed before exit, even if no new facts are on its fact queue,
492 * as it might decide to further instantiate some lemmas, precluding
495 inline bool needCheck() const {
496 return d_outputChannelUsed
|| d_lemmasAdded
;
499 * Is the literal lit (possibly) critical for satisfying the input formula in
500 * the current context? This call is applicable only during collectModelInfo
501 * or during LAST_CALL effort.
503 bool isRelevant(Node lit
) const;
505 * This is called at shutdown time by the SmtEngine, just before
506 * destruction. It is important because there are destruction
507 * ordering issues between PropEngine and Theory.
512 * Solve the given literal with a theory that owns it.
514 theory::Theory::PPAssertStatus
solve(TNode literal
,
515 theory::SubstitutionMap
& substitutionOut
);
518 * Preregister a Theory atom with the responsible theory (or
521 void preRegister(TNode preprocessed
);
524 * Assert the formula to the appropriate theory.
525 * @param node the assertion
527 void assertFact(TNode node
);
530 * Check all (currently-active) theories for conflicts.
531 * @param effort the effort level to use
533 void check(theory::Theory::Effort effort
);
536 * Calls ppStaticLearn() on all theories, accumulating their
537 * combined contributions in the "learned" builder.
539 void ppStaticLearn(TNode in
, NodeBuilder
<>& learned
);
542 * Calls presolve() on all theories and returns true
543 * if one of the theories discovers a conflict.
548 * Calls postsolve() on all theories.
553 * Calls notifyRestart() on all active theories.
555 void notifyRestart();
557 void getPropagatedLiterals(std::vector
<TNode
>& literals
) {
558 for (; d_propagatedLiteralsIndex
< d_propagatedLiterals
.size(); d_propagatedLiteralsIndex
= d_propagatedLiteralsIndex
+ 1) {
559 Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals
[d_propagatedLiteralsIndex
] << std::endl
;
560 literals
.push_back(d_propagatedLiterals
[d_propagatedLiteralsIndex
]);
565 * Returns the next decision request, or null if none exist. The next
566 * decision request is a literal that this theory engine prefers the SAT
567 * solver to make as its next decision. Decision requests are managed by
568 * the decision manager d_decManager.
570 Node
getNextDecisionRequest();
572 bool properConflict(TNode conflict
) const;
575 * Returns an explanation of the node propagated to the SAT solver.
577 theory::TrustNode
getExplanation(TNode node
);
580 * Get the pointer to the model object used by this theory engine.
582 theory::TheoryModel
* getModel();
584 * Get the current model for the current set of assertions. This method
585 * should only be called immediately after a satisfiable or unknown
586 * response to a check-sat call, and only if produceModels is true.
588 * If the model is not already built, this will cause this theory engine
589 * to build the model.
591 * If the model is not available (for instance, if the last call to check-sat
592 * was interrupted), then this returns the null pointer.
594 theory::TheoryModel
* getBuiltModel();
596 * This forces the model maintained by the combination engine to be built
597 * if it has not been done so already. This should be called only during a
598 * last call effort check after theory combination is run.
600 * @return true if the model was successfully built (possibly prior to this
604 /** set eager model building
606 * If this method is called, then this TheoryEngine will henceforth build
607 * its model immediately after every satisfiability check that results
608 * in a satisfiable or unknown result. The motivation for this mode is to
609 * accomodate API users that get the model object from the TheoryEngine,
610 * where we want to ensure that this model is always valid.
611 * TODO (#2648): revisit this.
613 void setEagerModelBuilding() { d_eager_model_building
= true; }
615 /** get synth solutions
617 * This method returns true if there is a synthesis solution available. This
618 * is the case if the last call to check satisfiability originated in a
619 * check-synth call, and the synthesis solver successfully found a solution
620 * for all active synthesis conjectures.
622 * This method adds entries to sol_map that map functions-to-synthesize with
623 * their solutions, for all active conjectures. This should be called
624 * immediately after the solver answers unsat for sygus input.
626 * For details on what is added to sol_map, see
627 * SynthConjecture::getSynthSolutions.
629 bool getSynthSolutions(std::map
<Node
, std::map
<Node
, Node
> >& sol_map
);
632 * Get the theory associated to a given Node.
634 * @returns the theory, or NULL if the TNode is
637 inline theory::Theory
* theoryOf(TNode node
) const {
638 return d_theoryTable
[theory::Theory::theoryOf(node
)];
642 * Get the theory associated to a the given theory id.
644 * @returns the theory
646 inline theory::Theory
* theoryOf(theory::TheoryId theoryId
) const {
647 Assert(theoryId
< theory::THEORY_LAST
);
648 return d_theoryTable
[theoryId
];
651 inline bool isTheoryEnabled(theory::TheoryId theoryId
) const {
652 return d_logicInfo
.isTheoryEnabled(theoryId
);
654 /** get the logic info used by this theory engine */
655 const LogicInfo
& getLogicInfo() const;
657 * Returns the equality status of the two terms, from the theory
658 * that owns the domain type. The types of a and b must be the same.
660 theory::EqualityStatus
getEqualityStatus(TNode a
, TNode b
);
663 * Returns the value that a theory that owns the type of var currently
664 * has (or null if none);
666 Node
getModelValue(TNode var
);
669 * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
671 Node
ensureLiteral(TNode n
);
674 * Print all instantiations made by the quantifiers module.
676 void printInstantiations( std::ostream
& out
);
679 * Print solution for synthesis conjectures found by ce_guided_instantiation module
681 void printSynthSolution( std::ostream
& out
);
684 * Get list of quantified formulas that were instantiated
686 void getInstantiatedQuantifiedFormulas( std::vector
< Node
>& qs
);
689 * Get instantiation methods
690 * first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
691 * second inputs forall x.q[x] and returns ( a, ..., z )
692 * third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] )
693 * , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
695 void getInstantiations( Node q
, std::vector
< Node
>& insts
);
696 void getInstantiationTermVectors( Node q
, std::vector
< std::vector
< Node
> >& tvecs
);
697 void getInstantiations( std::map
< Node
, std::vector
< Node
> >& insts
);
698 void getInstantiationTermVectors( std::map
< Node
, std::vector
< std::vector
< Node
> > >& insts
);
701 * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
702 * Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
704 Node
getInstantiatedConjunction( Node q
);
707 * Forwards an entailment check according to the given theoryOfMode.
708 * See theory.h for documentation on entailmentCheck().
710 std::pair
<bool, Node
> entailmentCheck(options::TheoryOfMode mode
, TNode lit
);
714 /** Dump the assertions to the dump */
715 void dumpAssertions(const char* tag
);
717 /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
720 SortInference
* getSortInference() { return &d_sortInfer
; }
722 /** Prints the assertions to the debug stream */
723 void printAssertions(const char* tag
);
727 std::map
< std::string
, std::vector
< theory::Theory
* > > d_attr_handle
;
730 /** Set user attribute.
732 * This function is called when an attribute is set by a user. In SMT-LIBv2
733 * this is done via the syntax (! n :attr)
735 void setUserAttribute(const std::string
& attr
,
737 const std::vector
<Node
>& node_values
,
738 const std::string
& str_value
);
740 /** Handle user attribute.
742 * Associates theory t with the attribute attr. Theory t will be
743 * notified whenever an attribute of name attr is set.
745 void handleUserAttribute(const char* attr
, theory::Theory
* t
);
748 * Check that the theory assertions are satisfied in the model.
749 * This function is called from the smt engine's checkModel routine.
751 void checkTheoryAssertionsWithModel(bool hardFailure
);
754 IntStat d_arithSubstitutionsAdded
;
756 };/* class TheoryEngine */
758 }/* CVC4 namespace */
760 #endif /* CVC4__THEORY_ENGINE_H */