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 "base/check.h"
26 #include "context/cdhashmap.h"
27 #include "expr/node.h"
28 #include "options/theory_options.h"
29 #include "theory/atom_requests.h"
30 #include "theory/engine_output_channel.h"
31 #include "theory/interrupted.h"
32 #include "theory/rewriter.h"
33 #include "theory/sort_inference.h"
34 #include "theory/theory.h"
35 #include "theory/theory_preprocessor.h"
36 #include "theory/trust_node.h"
37 #include "theory/trust_substitutions.h"
38 #include "theory/uf/equality_engine.h"
39 #include "theory/valuation.h"
40 #include "util/hash.h"
41 #include "util/statistics_registry.h"
42 #include "util/unsafe_interrupt_exception.h"
46 class ResourceManager
;
48 class TheoryEngineProofGenerator
;
51 * A pair of a theory and a node. This is used to mark the flow of
52 * propagations between theories.
54 struct NodeTheoryPair
{
56 theory::TheoryId d_theory
;
58 NodeTheoryPair(TNode n
, theory::TheoryId t
, size_t ts
= 0)
59 : d_node(n
), d_theory(t
), d_timestamp(ts
)
62 NodeTheoryPair() : d_theory(theory::THEORY_LAST
), d_timestamp() {}
63 // Comparison doesn't take into account the timestamp
64 bool operator == (const NodeTheoryPair
& pair
) const {
65 return d_node
== pair
.d_node
&& d_theory
== pair
.d_theory
;
67 };/* struct NodeTheoryPair */
69 struct NodeTheoryPairHashFunction
{
70 NodeHashFunction hashFunction
;
71 // Hash doesn't take into account the timestamp
72 size_t operator()(const NodeTheoryPair
& pair
) const {
73 uint64_t hash
= fnv1a::fnv1a_64(NodeHashFunction()(pair
.d_node
));
74 return static_cast<size_t>(fnv1a::fnv1a_64(pair
.d_theory
, hash
));
76 };/* struct NodeTheoryPairHashFunction */
79 /* Forward declarations */
82 class CombinationEngine
;
84 class DecisionManager
;
85 class RelevanceManager
;
87 }/* CVC4::theory namespace */
94 * This is essentially an abstraction for a collection of theories. A
95 * TheoryEngine provides services to a PropEngine, making various
96 * T-solvers look like a single unit to the propositional part of
101 /** Shared terms database can use the internals notify the theories */
102 friend class SharedTermsDatabase
;
103 friend class theory::EngineOutputChannel
;
104 friend class theory::CombinationEngine
;
105 friend class theory::SharedSolver
;
107 /** Associated PropEngine engine */
108 prop::PropEngine
* d_propEngine
;
111 context::Context
* d_context
;
113 /** Our user context */
114 context::UserContext
* d_userContext
;
117 * A table of from theory IDs to theory pointers. Never use this table
118 * directly, use theoryOf() instead.
120 theory::Theory
* d_theoryTable
[theory::THEORY_LAST
];
123 * A collection of theories that are "active" for the current run.
124 * This set is provided by the user (as a logic string, say, in SMT-LIBv2
125 * format input), or else by default it's all-inclusive. This is important
126 * because we can optimize for single-theory runs (no sharing), can reduce
127 * the cost of walking the DAG on registration, etc.
129 const LogicInfo
& d_logicInfo
;
130 /** The separation logic location and data types */
131 TypeNode d_sepLocType
;
132 TypeNode d_sepDataType
;
134 /** Reference to the output manager of the smt engine */
135 OutputManager
& d_outMgr
;
137 //--------------------------------- new proofs
138 /** Proof node manager used by this theory engine, if proofs are enabled */
139 ProofNodeManager
* d_pnm
;
140 /** The lazy proof object
142 * This stores instructions for how to construct proofs for all theory lemmas.
144 std::shared_ptr
<LazyCDProof
> d_lazyProof
;
145 /** The proof generator */
146 std::shared_ptr
<TheoryEngineProofGenerator
> d_tepg
;
147 //--------------------------------- end new proofs
148 /** The combination manager we are using */
149 std::unique_ptr
<theory::CombinationEngine
> d_tc
;
150 /** The shared solver of the above combination engine. */
151 theory::SharedSolver
* d_sharedSolver
;
152 /** The quantifiers engine, which is owned by the quantifiers theory */
153 theory::QuantifiersEngine
* d_quantEngine
;
155 * The decision manager
157 std::unique_ptr
<theory::DecisionManager
> d_decManager
;
158 /** The relevance manager */
159 std::unique_ptr
<theory::RelevanceManager
> d_relManager
;
161 /** are we in eager model building mode? (see setEagerModelBuilding). */
162 bool d_eager_model_building
;
165 * Output channels for individual theories.
167 theory::EngineOutputChannel
* d_theoryOut
[theory::THEORY_LAST
];
170 * Are we in conflict.
172 context::CDO
<bool> d_inConflict
;
175 * Are we in "SAT mode"? In this state, the user can query for the model.
176 * This corresponds to the state in Figure 4.1, page 52 of the SMT-LIB
177 * standard, version 2.6.
182 * Called by the theories to notify of a conflict.
184 * @param conflict The trust node containing the conflict and its proof
185 * generator (if it exists),
186 * @param theoryId The theory that sent the conflict
188 void conflict(theory::TrustNode conflict
, theory::TheoryId theoryId
);
191 * Debugging flag to ensure that shutdown() is called before the
197 * True if a theory has notified us of incompleteness (at this
198 * context level or below).
200 context::CDO
<bool> d_incomplete
;
203 * Called by the theories to notify that the current branch is incomplete.
205 void setIncomplete(theory::TheoryId theory
) {
210 * Mapping of propagations from recievers to senders.
212 typedef context::CDHashMap
<NodeTheoryPair
, NodeTheoryPair
, NodeTheoryPairHashFunction
> PropagationMap
;
213 PropagationMap d_propagationMap
;
216 * Timestamp of propagations
218 context::CDO
<size_t> d_propagationMapTimestamp
;
221 * Literals that are propagated by the theory. Note that these are TNodes.
222 * The theory can only propagate nodes that have an assigned literal in the
223 * SAT solver and are hence referenced in the SAT solver.
225 context::CDList
<TNode
> d_propagatedLiterals
;
228 * The index of the next literal to be propagated by a theory.
230 context::CDO
<unsigned> d_propagatedLiteralsIndex
;
233 * Called by the output channel to propagate literals and facts
234 * @return false if immediate conflict
236 bool propagate(TNode literal
, theory::TheoryId theory
);
239 * Internal method to call the propagation routines and collect the
240 * propagated literals.
242 void propagate(theory::Theory::Effort effort
);
245 * A variable to mark if we added any lemmas.
250 * A variable to mark if the OutputChannel was "used" by any theory
251 * since the start of the last check. If it has been, we require
252 * a FULL_EFFORT check before exiting and reporting SAT.
254 * See the documentation for the needCheck() function, below.
256 bool d_outputChannelUsed
;
258 /** Atom requests from lemmas */
259 AtomRequests d_atomRequests
;
262 * Adds a new lemma, returning its status.
263 * @param node the lemma
264 * @param p the properties of the lemma.
265 * @param atomsTo the theory that atoms of the lemma should be sent to
266 * @param from the theory that sent the lemma
268 void lemma(theory::TrustNode node
,
269 theory::LemmaProperty p
,
270 theory::TheoryId atomsTo
= theory::THEORY_LAST
,
271 theory::TheoryId from
= theory::THEORY_LAST
);
273 /** Enusre that the given atoms are send to the given theory */
274 void ensureLemmaAtoms(const std::vector
<TNode
>& atoms
, theory::TheoryId theory
);
276 /** sort inference module */
277 SortInference d_sortInfer
;
279 /** Time spent in theory combination */
280 TimerStat d_combineTheoriesTime
;
285 /** Whether we were just interrupted (or not) */
287 ResourceManager
* d_resourceManager
;
290 /** Constructs a theory engine */
291 TheoryEngine(context::Context
* context
,
292 context::UserContext
* userContext
,
294 const LogicInfo
& logic
,
295 OutputManager
& outMgr
,
296 ProofNodeManager
* pnm
);
298 /** Destroys a theory engine */
303 /** "Spend" a resource during a search or preprocessing.*/
304 void spendResource(ResourceManager::Resource r
);
307 * Adds a theory. Only one theory per TheoryId can be present, so if
308 * there is another theory it will be deleted.
310 template <class TheoryClass
>
311 inline void addTheory(theory::TheoryId theoryId
)
313 Assert(d_theoryTable
[theoryId
] == NULL
&& d_theoryOut
[theoryId
] == NULL
);
314 d_theoryOut
[theoryId
] = new theory::EngineOutputChannel(this, theoryId
);
315 d_theoryTable
[theoryId
] = new TheoryClass(d_context
,
317 *d_theoryOut
[theoryId
],
318 theory::Valuation(this),
321 theory::Rewriter::registerTheoryRewriter(
322 theoryId
, d_theoryTable
[theoryId
]->getTheoryRewriter());
325 void setPropEngine(prop::PropEngine
* propEngine
)
327 d_propEngine
= propEngine
;
331 * Called when all initialization of options/logic is done, after theory
332 * objects have been created.
334 * This initializes the quantifiers engine, the "official" equality engines
335 * of each theory as required, and the model and model builder utilities.
340 * Get a pointer to the underlying propositional engine.
342 inline prop::PropEngine
* getPropEngine() const {
346 /** Get the proof node manager */
347 ProofNodeManager
* getProofNodeManager() const;
350 * Get a pointer to the underlying sat context.
352 context::Context
* getSatContext() const { return d_context
; }
355 * Get a pointer to the underlying user context.
357 context::UserContext
* getUserContext() const { return d_userContext
; }
360 * Get a pointer to the underlying quantifiers engine.
362 theory::QuantifiersEngine
* getQuantifiersEngine() const {
363 return d_quantEngine
;
366 * Get a pointer to the underlying decision manager.
368 theory::DecisionManager
* getDecisionManager() const
370 return d_decManager
.get();
375 * Queue of nodes for pre-registration.
377 std::queue
<TNode
> d_preregisterQueue
;
380 * Boolean flag denoting we are in pre-registration.
382 bool d_inPreregister
;
385 * Did the theories get any new facts since the last time we called
388 context::CDO
<bool> d_factsAsserted
;
391 * Assert the formula to the given theory.
392 * @param assertion the assertion to send (not necesserily normalized)
393 * @param original the assertion as it was sent in from the propagating theory
394 * @param toTheoryId the theory to assert to
395 * @param fromTheoryId the theory that sent it
397 void assertToTheory(TNode assertion
, TNode originalAssertion
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
400 * Marks a theory propagation from a theory to a theory where a
401 * theory could be the THEORY_SAT_SOLVER for literals coming from
402 * or being propagated to the SAT solver. If the receiving theory
403 * already recieved the literal, the method returns false, otherwise
406 * @param assertion the normalized assertion being sent
407 * @param originalAssertion the actual assertion that was sent
408 * @param toTheoryId the theory that is on the receiving end
409 * @param fromTheoryId the theory that sent the assertion
410 * @return true if a new assertion, false if theory already got it
412 bool markPropagation(TNode assertion
, TNode originalAssertions
, theory::TheoryId toTheoryId
, theory::TheoryId fromTheoryId
);
415 * Computes the explanation by traversing the propagation graph and
416 * asking relevant theories to explain the propagations. Initially
417 * the explanation vector should contain only the element (node, theory)
418 * where the node is the one to be explained, and the theory is the
419 * theory that sent the literal.
421 theory::TrustNode
getExplanation(
422 std::vector
<NodeTheoryPair
>& explanationVector
);
424 /** Are proofs enabled? */
425 bool isProofEnabled() const;
429 * Preprocess rewrite equality, called by the preprocessor to rewrite
430 * equalities appearing in the input.
432 theory::TrustNode
ppRewriteEquality(TNode eq
);
433 /** Notify (preprocessed) assertions. */
434 void notifyPreprocessedAssertions(const std::vector
<Node
>& assertions
);
436 /** Return whether or not we are incomplete (in the current context). */
437 inline bool isIncomplete() const { return d_incomplete
; }
440 * Returns true if we need another round of checking. If this
441 * returns true, check(FULL_EFFORT) _must_ be called by the
442 * propositional layer before reporting SAT.
444 * This is especially necessary for incomplete theories that lazily
445 * output some lemmas on FULL_EFFORT check (e.g. quantifier reasoning
446 * outputing quantifier instantiations). In such a case, a lemma can
447 * be asserted that is simplified away (perhaps it's already true).
448 * However, we must maintain the invariant that, if a theory uses the
449 * OutputChannel, it implicitly requests that another check(FULL_EFFORT)
450 * be performed before exit, even if no new facts are on its fact queue,
451 * as it might decide to further instantiate some lemmas, precluding
454 inline bool needCheck() const {
455 return d_outputChannelUsed
|| d_lemmasAdded
;
458 * Is the literal lit (possibly) critical for satisfying the input formula in
459 * the current context? This call is applicable only during collectModelInfo
460 * or during LAST_CALL effort.
462 bool isRelevant(Node lit
) const;
464 * This is called at shutdown time by the SmtEngine, just before
465 * destruction. It is important because there are destruction
466 * ordering issues between PropEngine and Theory.
471 * Solve the given literal with a theory that owns it. The proof of tliteral
472 * is carried in the trust node. The proof added to substitutionOut should
473 * take this proof into account (when proofs are enabled).
475 theory::Theory::PPAssertStatus
solve(
476 theory::TrustNode tliteral
,
477 theory::TrustSubstitutionMap
& substitutionOut
);
480 * Preregister a Theory atom with the responsible theory (or
483 void preRegister(TNode preprocessed
);
486 * Assert the formula to the appropriate theory.
487 * @param node the assertion
489 void assertFact(TNode node
);
492 * Check all (currently-active) theories for conflicts.
493 * @param effort the effort level to use
495 void check(theory::Theory::Effort effort
);
498 * Calls ppStaticLearn() on all theories, accumulating their
499 * combined contributions in the "learned" builder.
501 void ppStaticLearn(TNode in
, NodeBuilder
<>& learned
);
504 * Calls presolve() on all theories and returns true
505 * if one of the theories discovers a conflict.
510 * Calls postsolve() on all theories.
515 * Calls notifyRestart() on all active theories.
517 void notifyRestart();
519 void getPropagatedLiterals(std::vector
<TNode
>& literals
) {
520 for (; d_propagatedLiteralsIndex
< d_propagatedLiterals
.size(); d_propagatedLiteralsIndex
= d_propagatedLiteralsIndex
+ 1) {
521 Debug("getPropagatedLiterals") << "TheoryEngine::getPropagatedLiterals: propagating: " << d_propagatedLiterals
[d_propagatedLiteralsIndex
] << std::endl
;
522 literals
.push_back(d_propagatedLiterals
[d_propagatedLiteralsIndex
]);
527 * Returns the next decision request, or null if none exist. The next
528 * decision request is a literal that this theory engine prefers the SAT
529 * solver to make as its next decision. Decision requests are managed by
530 * the decision manager d_decManager.
532 Node
getNextDecisionRequest();
534 bool properConflict(TNode conflict
) const;
537 * Returns an explanation of the node propagated to the SAT solver.
539 theory::TrustNode
getExplanation(TNode node
);
542 * Get the pointer to the model object used by this theory engine.
544 theory::TheoryModel
* getModel();
546 * Get the current model for the current set of assertions. This method
547 * should only be called immediately after a satisfiable or unknown
548 * response to a check-sat call, and only if produceModels is true.
550 * If the model is not already built, this will cause this theory engine
551 * to build the model.
553 * If the model is not available (for instance, if the last call to check-sat
554 * was interrupted), then this returns the null pointer.
556 theory::TheoryModel
* getBuiltModel();
558 * This forces the model maintained by the combination engine to be built
559 * if it has not been done so already. This should be called only during a
560 * last call effort check after theory combination is run.
562 * @return true if the model was successfully built (possibly prior to this
566 /** set eager model building
568 * If this method is called, then this TheoryEngine will henceforth build
569 * its model immediately after every satisfiability check that results
570 * in a satisfiable or unknown result. The motivation for this mode is to
571 * accomodate API users that get the model object from the TheoryEngine,
572 * where we want to ensure that this model is always valid.
573 * TODO (#2648): revisit this.
575 void setEagerModelBuilding() { d_eager_model_building
= true; }
578 * Get the theory associated to a given Node.
580 * @returns the theory, or NULL if the TNode is
583 inline theory::Theory
* theoryOf(TNode node
) const {
584 return d_theoryTable
[theory::Theory::theoryOf(node
)];
588 * Get the theory associated to a the given theory id.
590 * @returns the theory
592 inline theory::Theory
* theoryOf(theory::TheoryId theoryId
) const {
593 Assert(theoryId
< theory::THEORY_LAST
);
594 return d_theoryTable
[theoryId
];
597 inline bool isTheoryEnabled(theory::TheoryId theoryId
) const {
598 return d_logicInfo
.isTheoryEnabled(theoryId
);
600 /** get the logic info used by this theory engine */
601 const LogicInfo
& getLogicInfo() const;
602 /** get the separation logic heap types */
603 bool getSepHeapTypes(TypeNode
& locType
, TypeNode
& dataType
) const;
606 * Declare heap. This is used for separation logics to set the location
607 * and data types. It should be called only once, and before any separation
608 * logic constraints are asserted to this theory engine.
610 void declareSepHeap(TypeNode locT
, TypeNode dataT
);
613 * Returns the equality status of the two terms, from the theory
614 * that owns the domain type. The types of a and b must be the same.
616 theory::EqualityStatus
getEqualityStatus(TNode a
, TNode b
);
619 * Returns the value that a theory that owns the type of var currently
620 * has (or null if none);
622 Node
getModelValue(TNode var
);
625 * Forwards an entailment check according to the given theoryOfMode.
626 * See theory.h for documentation on entailmentCheck().
628 std::pair
<bool, Node
> entailmentCheck(options::TheoryOfMode mode
, TNode lit
);
632 /** Dump the assertions to the dump */
633 void dumpAssertions(const char* tag
);
635 /** For preprocessing pass lifting bit-vectors of size 1 to booleans */
638 SortInference
* getSortInference() { return &d_sortInfer
; }
640 /** Prints the assertions to the debug stream */
641 void printAssertions(const char* tag
);
645 std::map
< std::string
, std::vector
< theory::Theory
* > > d_attr_handle
;
648 /** Set user attribute.
650 * This function is called when an attribute is set by a user. In SMT-LIBv2
651 * this is done via the syntax (! n :attr)
653 void setUserAttribute(const std::string
& attr
,
655 const std::vector
<Node
>& node_values
,
656 const std::string
& str_value
);
658 /** Handle user attribute.
660 * Associates theory t with the attribute attr. Theory t will be
661 * notified whenever an attribute of name attr is set.
663 void handleUserAttribute(const char* attr
, theory::Theory
* t
);
666 * Check that the theory assertions are satisfied in the model.
667 * This function is called from the smt engine's checkModel routine.
669 void checkTheoryAssertionsWithModel(bool hardFailure
);
670 };/* class TheoryEngine */
672 }/* CVC4 namespace */
674 #endif /* CVC4__THEORY_ENGINE_H */