1 /********************* */
2 /*! \file theory_engine.h
4 ** Top contributors (to current version):
5 ** Andrew Reynolds, Dejan Jovanovic, 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 "theory/atom_requests.h"
37 #include "theory/engine_output_channel.h"
38 #include "theory/interrupted.h"
39 #include "theory/rewriter.h"
40 #include "theory/sort_inference.h"
41 #include "theory/term_registration_visitor.h"
42 #include "theory/theory.h"
43 #include "theory/theory_preprocessor.h"
44 #include "theory/trust_node.h"
45 #include "theory/trust_substitutions.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
;
92 class DecisionManager
;
93 class RelevanceManager
;
99 class EntailmentCheckParameters
;
100 class EntailmentCheckSideEffects
;
101 }/* CVC4::theory namespace */
103 class RemoveTermFormulas
;
106 * This is essentially an abstraction for a collection of theories. A
107 * TheoryEngine provides services to a PropEngine, making various
108 * T-solvers look like a single unit to the propositional part of
113 /** Shared terms database can use the internals notify the theories */
114 friend class SharedTermsDatabase
;
115 friend class theory::EngineOutputChannel
;
116 friend class theory::CombinationEngine
;
117 friend class theory::SharedSolver
;
119 /** Associated PropEngine engine */
120 prop::PropEngine
* d_propEngine
;
123 context::Context
* d_context
;
125 /** Our user context */
126 context::UserContext
* d_userContext
;
129 * A table of from theory IDs to theory pointers. Never use this table
130 * directly, use theoryOf() instead.
132 theory::Theory
* d_theoryTable
[theory::THEORY_LAST
];
135 * A collection of theories that are "active" for the current run.
136 * This set is provided by the user (as a logic string, say, in SMT-LIBv2
137 * format input), or else by default it's all-inclusive. This is important
138 * because we can optimize for single-theory runs (no sharing), can reduce
139 * the cost of walking the DAG on registration, etc.
141 const LogicInfo
& d_logicInfo
;
143 /** Reference to the output manager of the smt engine */
144 OutputManager
& d_outMgr
;
146 //--------------------------------- new proofs
147 /** Proof node manager used by this theory engine, if proofs are enabled */
148 ProofNodeManager
* d_pnm
;
149 /** The lazy proof object
151 * This stores instructions for how to construct proofs for all theory lemmas.
153 std::shared_ptr
<LazyCDProof
> d_lazyProof
;
154 /** The proof generator */
155 std::shared_ptr
<TheoryEngineProofGenerator
> d_tepg
;
156 //--------------------------------- end new proofs
157 /** The combination manager we are using */
158 std::unique_ptr
<theory::CombinationEngine
> d_tc
;
159 /** The shared solver of the above combination engine. */
160 theory::SharedSolver
* d_sharedSolver
;
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 /** are we in eager model building mode? (see setEagerModelBuilding). */
176 bool d_eager_model_building
;
179 * Output channels for individual theories.
181 theory::EngineOutputChannel
* d_theoryOut
[theory::THEORY_LAST
];
184 * Are we in conflict.
186 context::CDO
<bool> d_inConflict
;
189 * Are we in "SAT mode"? In this state, the user can query for the model.
190 * This corresponds to the state in Figure 4.1, page 52 of the SMT-LIB
191 * standard, version 2.6.
196 * Called by the theories to notify of a conflict.
198 * @param conflict The trust node containing the conflict and its proof
199 * generator (if it exists),
200 * @param theoryId The theory that sent the conflict
202 void conflict(theory::TrustNode conflict
, theory::TheoryId theoryId
);
205 * Debugging flag to ensure that shutdown() is called before the
211 * True if a theory has notified us of incompleteness (at this
212 * context level or below).
214 context::CDO
<bool> d_incomplete
;
217 * Called by the theories to notify that the current branch is incomplete.
219 void setIncomplete(theory::TheoryId theory
) {
224 * Mapping of propagations from recievers to senders.
226 typedef context::CDHashMap
<NodeTheoryPair
, NodeTheoryPair
, NodeTheoryPairHashFunction
> PropagationMap
;
227 PropagationMap d_propagationMap
;
230 * Timestamp of propagations
232 context::CDO
<size_t> d_propagationMapTimestamp
;
235 * Literals that are propagated by the theory. Note that these are TNodes.
236 * The theory can only propagate nodes that have an assigned literal in the
237 * SAT solver and are hence referenced in the SAT solver.
239 context::CDList
<TNode
> d_propagatedLiterals
;
242 * The index of the next literal to be propagated by a theory.
244 context::CDO
<unsigned> d_propagatedLiteralsIndex
;
247 * Called by the output channel to propagate literals and facts
248 * @return false if immediate conflict
250 bool propagate(TNode literal
, theory::TheoryId theory
);
253 * Internal method to call the propagation routines and collect the
254 * propagated literals.
256 void propagate(theory::Theory::Effort effort
);
259 * A variable to mark if we added any lemmas.
264 * A variable to mark if the OutputChannel was "used" by any theory
265 * since the start of the last check. If it has been, we require
266 * a FULL_EFFORT check before exiting and reporting SAT.
268 * See the documentation for the needCheck() function, below.
270 bool d_outputChannelUsed
;
272 /** Atom requests from lemmas */
273 AtomRequests d_atomRequests
;
276 * Adds a new lemma, returning its status.
277 * @param node the lemma
278 * @param p the properties of the lemma.
279 * @param atomsTo the theory that atoms of the lemma should be sent to
280 * @param from the theory that sent the lemma
281 * @return a lemma status, containing the lemma and context information
282 * about when it was sent.
284 theory::LemmaStatus
lemma(theory::TrustNode node
,
285 theory::LemmaProperty p
,
286 theory::TheoryId atomsTo
= theory::THEORY_LAST
,
287 theory::TheoryId from
= theory::THEORY_LAST
);
289 /** Enusre that the given atoms are send to the given theory */
290 void ensureLemmaAtoms(const std::vector
<TNode
>& atoms
, theory::TheoryId theory
);
292 /** sort inference module */
293 SortInference d_sortInfer
;
295 /** The theory preprocessor */
296 theory::TheoryPreprocessor d_tpp
;
298 /** Time spent in theory combination */
299 TimerStat d_combineTheoriesTime
;
304 /** Whether we were just interrupted (or not) */
306 ResourceManager
* d_resourceManager
;
309 /** Constructs a theory engine */
310 TheoryEngine(context::Context
* context
,
311 context::UserContext
* userContext
,
313 RemoveTermFormulas
& iteRemover
,
314 const LogicInfo
& logic
,
315 OutputManager
& outMgr
,
316 ProofNodeManager
* pnm
);
318 /** Destroys a theory engine */
323 /** "Spend" a resource during a search or preprocessing.*/
324 void spendResource(ResourceManager::Resource r
);
327 * Adds a theory. Only one theory per TheoryId can be present, so if
328 * there is another theory it will be deleted.
330 template <class TheoryClass
>
331 inline void addTheory(theory::TheoryId theoryId
)
333 Assert(d_theoryTable
[theoryId
] == NULL
&& d_theoryOut
[theoryId
] == NULL
);
334 d_theoryOut
[theoryId
] = new theory::EngineOutputChannel(this, theoryId
);
335 d_theoryTable
[theoryId
] = new TheoryClass(d_context
,
337 *d_theoryOut
[theoryId
],
338 theory::Valuation(this),
341 theory::Rewriter::registerTheoryRewriter(
342 theoryId
, d_theoryTable
[theoryId
]->getTheoryRewriter());
345 void setPropEngine(prop::PropEngine
* propEngine
)
347 d_propEngine
= propEngine
;
351 * Called when all initialization of options/logic is done, after theory
352 * objects have been created.
354 * This initializes the quantifiers engine, the "official" equality engines
355 * of each theory as required, and the model and model builder utilities.
360 * Get a pointer to the underlying propositional engine.
362 inline prop::PropEngine
* getPropEngine() const {
366 /** Get the proof node manager */
367 ProofNodeManager
* getProofNodeManager() const;
370 * Get a pointer to the underlying sat context.
372 context::Context
* getSatContext() const { return d_context
; }
375 * Get a pointer to the underlying user context.
377 context::UserContext
* getUserContext() const { return d_userContext
; }
380 * Get a pointer to the underlying quantifiers engine.
382 theory::QuantifiersEngine
* getQuantifiersEngine() const {
383 return d_quantEngine
;
386 * Get a pointer to the underlying decision manager.
388 theory::DecisionManager
* getDecisionManager() const
390 return d_decManager
.get();
395 * Queue of nodes for pre-registration.
397 std::queue
<TNode
> d_preregisterQueue
;
400 * Boolean flag denoting we are in pre-registration.
402 bool d_inPreregister
;
405 * Did the theories get any new facts since the last time we called
408 context::CDO
<bool> d_factsAsserted
;
411 * Assert the formula to the given theory.
412 * @param assertion the assertion to send (not necesserily normalized)
413 * @param original the assertion as it was sent in from the propagating theory
414 * @param toTheoryId the theory to assert to
415 * @param fromTheoryId the theory that sent it
417 void assertToTheory(TNode assertion
, TNode originalAssertion
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
420 * Marks a theory propagation from a theory to a theory where a
421 * theory could be the THEORY_SAT_SOLVER for literals coming from
422 * or being propagated to the SAT solver. If the receiving theory
423 * already recieved the literal, the method returns false, otherwise
426 * @param assertion the normalized assertion being sent
427 * @param originalAssertion the actual assertion that was sent
428 * @param toTheoryId the theory that is on the receiving end
429 * @param fromTheoryId the theory that sent the assertion
430 * @return true if a new assertion, false if theory already got it
432 bool markPropagation(TNode assertion
, TNode originalAssertions
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
435 * Computes the explanation by traversing the propagation graph and
436 * asking relevant theories to explain the propagations. Initially
437 * the explanation vector should contain only the element (node, theory)
438 * where the node is the one to be explained, and the theory is the
439 * theory that sent the literal.
441 theory::TrustNode
getExplanation(
442 std::vector
<NodeTheoryPair
>& explanationVector
);
444 /** Are proofs enabled? */
445 bool isProofEnabled() const;
449 * Runs theory specific preprocessing on the non-Boolean parts of
450 * the formula. This is only called on input assertions, after ITEs
453 theory::TrustNode
preprocess(TNode node
);
455 /** Notify (preprocessed) assertions. */
456 void notifyPreprocessedAssertions(const std::vector
<Node
>& assertions
);
458 /** Return whether or not we are incomplete (in the current context). */
459 inline bool isIncomplete() const { return d_incomplete
; }
462 * Returns true if we need another round of checking. If this
463 * returns true, check(FULL_EFFORT) _must_ be called by the
464 * propositional layer before reporting SAT.
466 * This is especially necessary for incomplete theories that lazily
467 * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
468 * outputing quantifier instantiations). In such a case, a lemma can
469 * be asserted that is simplified away (perhaps it's already true).
470 * However, we must maintain the invariant that, if a theory uses the
471 * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
472 * be performed before exit, even if no new facts are on its fact queue,
473 * as it might decide to further instantiate some lemmas, precluding
476 inline bool needCheck() const {
477 return d_outputChannelUsed
|| d_lemmasAdded
;
480 * Is the literal lit (possibly) critical for satisfying the input formula in
481 * the current context? This call is applicable only during collectModelInfo
482 * or during LAST_CALL effort.
484 bool isRelevant(Node lit
) const;
486 * This is called at shutdown time by the SmtEngine, just before
487 * destruction. It is important because there are destruction
488 * ordering issues between PropEngine and Theory.
493 * Solve the given literal with a theory that owns it. The proof of tliteral
494 * is carried in the trust node. The proof added to substitutionOut should
495 * take this proof into account (when proofs are enabled).
497 theory::Theory::PPAssertStatus
solve(
498 theory::TrustNode tliteral
,
499 theory::TrustSubstitutionMap
& substitutionOut
);
502 * Preregister a Theory atom with the responsible theory (or
505 void preRegister(TNode preprocessed
);
508 * Assert the formula to the appropriate theory.
509 * @param node the assertion
511 void assertFact(TNode node
);
514 * Check all (currently-active) theories for conflicts.
515 * @param effort the effort level to use
517 void check(theory::Theory::Effort effort
);
520 * Calls ppStaticLearn() on all theories, accumulating their
521 * combined contributions in the "learned" builder.
523 void ppStaticLearn(TNode in
, NodeBuilder
<>& learned
);
526 * Calls presolve() on all theories and returns true
527 * if one of the theories discovers a conflict.
532 * Calls postsolve() on all theories.
537 * Calls notifyRestart() on all active theories.
539 void notifyRestart();
541 void getPropagatedLiterals(std::vector
<TNode
>& literals
) {
542 for (; d_propagatedLiteralsIndex
< d_propagatedLiterals
.size(); d_propagatedLiteralsIndex
= d_propagatedLiteralsIndex
+ 1) {
543 Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals
[d_propagatedLiteralsIndex
] << std::endl
;
544 literals
.push_back(d_propagatedLiterals
[d_propagatedLiteralsIndex
]);
549 * Returns the next decision request, or null if none exist. The next
550 * decision request is a literal that this theory engine prefers the SAT
551 * solver to make as its next decision. Decision requests are managed by
552 * the decision manager d_decManager.
554 Node
getNextDecisionRequest();
556 bool properConflict(TNode conflict
) const;
559 * Returns an explanation of the node propagated to the SAT solver.
561 theory::TrustNode
getExplanation(TNode node
);
564 * Get the pointer to the model object used by this theory engine.
566 theory::TheoryModel
* getModel();
568 * Get the current model for the current set of assertions. This method
569 * should only be called immediately after a satisfiable or unknown
570 * response to a check-sat call, and only if produceModels is true.
572 * If the model is not already built, this will cause this theory engine
573 * to build the model.
575 * If the model is not available (for instance, if the last call to check-sat
576 * was interrupted), then this returns the null pointer.
578 theory::TheoryModel
* getBuiltModel();
580 * This forces the model maintained by the combination engine to be built
581 * if it has not been done so already. This should be called only during a
582 * last call effort check after theory combination is run.
584 * @return true if the model was successfully built (possibly prior to this
588 /** set eager model building
590 * If this method is called, then this TheoryEngine will henceforth build
591 * its model immediately after every satisfiability check that results
592 * in a satisfiable or unknown result. The motivation for this mode is to
593 * accomodate API users that get the model object from the TheoryEngine,
594 * where we want to ensure that this model is always valid.
595 * TODO (#2648): revisit this.
597 void setEagerModelBuilding() { d_eager_model_building
= true; }
599 /** get synth solutions
601 * This method returns true if there is a synthesis solution available. This
602 * is the case if the last call to check satisfiability originated in a
603 * check-synth call, and the synthesis solver successfully found a solution
604 * for all active synthesis conjectures.
606 * This method adds entries to sol_map that map functions-to-synthesize with
607 * their solutions, for all active conjectures. This should be called
608 * immediately after the solver answers unsat for sygus input.
610 * For details on what is added to sol_map, see
611 * SynthConjecture::getSynthSolutions.
613 bool getSynthSolutions(std::map
<Node
, std::map
<Node
, Node
> >& sol_map
);
616 * Get the theory associated to a given Node.
618 * @returns the theory, or NULL if the TNode is
621 inline theory::Theory
* theoryOf(TNode node
) const {
622 return d_theoryTable
[theory::Theory::theoryOf(node
)];
626 * Get the theory associated to a the given theory id.
628 * @returns the theory
630 inline theory::Theory
* theoryOf(theory::TheoryId theoryId
) const {
631 Assert(theoryId
< theory::THEORY_LAST
);
632 return d_theoryTable
[theoryId
];
635 inline bool isTheoryEnabled(theory::TheoryId theoryId
) const {
636 return d_logicInfo
.isTheoryEnabled(theoryId
);
638 /** get the logic info used by this theory engine */
639 const LogicInfo
& getLogicInfo() const;
641 * Returns the equality status of the two terms, from the theory
642 * that owns the domain type. The types of a and b must be the same.
644 theory::EqualityStatus
getEqualityStatus(TNode a
, TNode b
);
647 * Returns the value that a theory that owns the type of var currently
648 * has (or null if none);
650 Node
getModelValue(TNode var
);
653 * Takes a literal and returns an equivalent literal that is guaranteed to be a SAT literal
655 Node
ensureLiteral(TNode n
);
658 * Print all instantiations made by the quantifiers module.
660 void printInstantiations( std::ostream
& out
);
663 * Print solution for synthesis conjectures found by ce_guided_instantiation module
665 void printSynthSolution( std::ostream
& out
);
668 * Get list of quantified formulas that were instantiated
670 void getInstantiatedQuantifiedFormulas( std::vector
< Node
>& qs
);
673 * Get instantiation methods
674 * first inputs forall x.q[x] and returns ( q[a], ..., q[z] )
675 * second inputs forall x.q[x] and returns ( a, ..., z )
676 * third and fourth return mappings e.g. forall x.q1[x] -> ( q1[a]...q1[z] )
677 * , ... , forall x.qn[x] -> ( qn[a]...qn[z] )
679 void getInstantiations( Node q
, std::vector
< Node
>& insts
);
680 void getInstantiationTermVectors( Node q
, std::vector
< std::vector
< Node
> >& tvecs
);
681 void getInstantiations( std::map
< Node
, std::vector
< Node
> >& insts
);
682 void getInstantiationTermVectors( std::map
< Node
, std::vector
< std::vector
< Node
> > >& insts
);
685 * Get instantiated conjunction, returns q[t1] ^ ... ^ q[tn] where t1...tn are current set of instantiations for q.
686 * Can be used for quantifier elimination when satisfiable and q[t1] ^ ... ^ q[tn] |= q
688 Node
getInstantiatedConjunction( Node q
);
691 * Forwards an entailment check according to the given theoryOfMode.
692 * See theory.h for documentation on entailmentCheck().
694 std::pair
<bool, Node
> entailmentCheck(options::TheoryOfMode mode
, TNode lit
);
698 /** Dump the assertions to the dump */
699 void dumpAssertions(const char* tag
);
701 /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
704 SortInference
* getSortInference() { return &d_sortInfer
; }
706 /** Prints the assertions to the debug stream */
707 void printAssertions(const char* tag
);
711 std::map
< std::string
, std::vector
< theory::Theory
* > > d_attr_handle
;
714 /** Set user attribute.
716 * This function is called when an attribute is set by a user. In SMT-LIBv2
717 * this is done via the syntax (! n :attr)
719 void setUserAttribute(const std::string
& attr
,
721 const std::vector
<Node
>& node_values
,
722 const std::string
& str_value
);
724 /** Handle user attribute.
726 * Associates theory t with the attribute attr. Theory t will be
727 * notified whenever an attribute of name attr is set.
729 void handleUserAttribute(const char* attr
, theory::Theory
* t
);
732 * Check that the theory assertions are satisfied in the model.
733 * This function is called from the smt engine's checkModel routine.
735 void checkTheoryAssertionsWithModel(bool hardFailure
);
738 IntStat d_arithSubstitutionsAdded
;
739 };/* class TheoryEngine */
741 }/* CVC4 namespace */
743 #endif /* CVC4__THEORY_ENGINE_H */