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/******************************************************************************
* Top contributors (to current version):
* Andres Noetzli, Andrew Reynolds, Morgan Deters
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
* in the top-level source directory and their institutional affiliations.
* All rights reserved. See the file COPYING in the top-level source
* directory for licensing information.
* ****************************************************************************
*
* AssertionPipeline stores a list of assertions modified by
* preprocessing passes.
*/
#include "cvc4_private.h"
#ifndef CVC5__PREPROCESSING__ASSERTION_PIPELINE_H
#define CVC5__PREPROCESSING__ASSERTION_PIPELINE_H
#include <vector>
#include "expr/node.h"
#include "theory/trust_node.h"
namespace cvc5 {
class ProofGenerator;
namespace smt {
class PreprocessProofGenerator;
}
namespace preprocessing {
using IteSkolemMap = std::unordered_map<size_t, Node>;
/**
* Assertion Pipeline stores a list of assertions modified by preprocessing
* passes. It is assumed that all assertions after d_realAssertionsEnd were
* generated by ITE removal. Hence, d_iteSkolemMap maps into only these.
*/
class AssertionPipeline
{
public:
AssertionPipeline();
size_t size() const { return d_nodes.size(); }
void resize(size_t n) { d_nodes.resize(n); }
/**
* Clear the list of assertions and assumptions.
*/
void clear();
const Node& operator[](size_t i) const { return d_nodes[i]; }
/**
* Adds an assertion/assumption to be preprocessed.
*
* @param n The assertion/assumption
* @param isAssumption If true, records that \p n is an assumption. Note that
* all assumptions have to be added contiguously.
* @param isInput If true, n is an input formula (an assumption in the main
* body of the overall proof).
* @param pg The proof generator who can provide a proof of n. The proof
* generator is not required and is ignored if isInput is true.
*/
void push_back(Node n,
bool isAssumption = false,
bool isInput = false,
ProofGenerator* pg = nullptr);
/** Same as above, with TrustNode */
void pushBackTrusted(theory::TrustNode trn);
/**
* Get the constant reference to the underlying assertions. It is only
* possible to modify these via the replace methods below.
*/
const std::vector<Node>& ref() const { return d_nodes; }
std::vector<Node>::const_iterator begin() const { return d_nodes.cbegin(); }
std::vector<Node>::const_iterator end() const { return d_nodes.cend(); }
/*
* Replaces assertion i with node n and records the dependency between the
* original assertion and its replacement.
*
* @param i The position of the assertion to replace.
* @param n The replacement assertion.
* @param pg The proof generator who can provide a proof of d_nodes[i] == n,
* where d_nodes[i] is the assertion at position i prior to this call.
*/
void replace(size_t i, Node n, ProofGenerator* pg = nullptr);
/**
* Same as above, with TrustNode trn, which is of kind REWRITE and proves
* d_nodes[i] = n for some n.
*/
void replaceTrusted(size_t i, theory::TrustNode trn);
IteSkolemMap& getIteSkolemMap() { return d_iteSkolemMap; }
const IteSkolemMap& getIteSkolemMap() const { return d_iteSkolemMap; }
size_t getRealAssertionsEnd() const { return d_realAssertionsEnd; }
/** @return The index of the first assumption */
size_t getAssumptionsStart() const { return d_assumptionsStart; }
/** @return The number of assumptions */
size_t getNumAssumptions() const { return d_numAssumptions; }
void updateRealAssertionsEnd() { d_realAssertionsEnd = d_nodes.size(); }
/**
* Returns true if substitutions must be stored as assertions. This is for
* example the case when we do incremental solving.
*/
bool storeSubstsInAsserts() { return d_storeSubstsInAsserts; }
/**
* Enables storing substitutions as assertions.
*/
void enableStoreSubstsInAsserts();
/**
* Disables storing substitutions as assertions.
*/
void disableStoreSubstsInAsserts();
/**
* Adds a substitution node of the form (= lhs rhs) to the assertions.
* This conjoins n to assertions at a distinguished index given by
* d_substsIndex.
*
* @param n The substitution node
* @param pg The proof generator that can provide a proof of n.
*/
void addSubstitutionNode(Node n, ProofGenerator* pg = nullptr);
/**
* Conjoin n to the assertion vector at position i. This replaces
* d_nodes[i] with the rewritten form of (AND d_nodes[i] n).
*
* @param i The assertion to replace
* @param n The formula to conjoin at position i
* @param pg The proof generator that can provide a proof of n
*/
void conjoin(size_t i, Node n, ProofGenerator* pg = nullptr);
/**
* Checks whether the assertion at a given index represents substitutions.
*
* @param i The index in question
*/
bool isSubstsIndex(size_t i)
{
return d_storeSubstsInAsserts && i == d_substsIndex;
}
//------------------------------------ for proofs
/** Set proof generator */
void setProofGenerator(smt::PreprocessProofGenerator* pppg);
/** Is proof enabled? */
bool isProofEnabled() const;
//------------------------------------ end for proofs
private:
/** The list of current assertions */
std::vector<Node> d_nodes;
/**
* Map from skolem variables to index in d_assertions containing
* corresponding introduced Boolean ite
*/
IteSkolemMap d_iteSkolemMap;
/** Size of d_nodes when preprocessing starts */
size_t d_realAssertionsEnd;
/**
* If true, we store the substitutions as assertions. This is necessary when
* doing incremental solving because we cannot apply them to existing
* assertions while preprocessing new assertions.
*/
bool d_storeSubstsInAsserts;
/**
* The index of the assertions that holds the substitutions.
*
* TODO(#2473): replace by separate vector of substitution assertions.
*/
size_t d_substsIndex;
/** Index of the first assumption */
size_t d_assumptionsStart;
/** The number of assumptions */
size_t d_numAssumptions;
/** The proof generator, if one is provided */
smt::PreprocessProofGenerator* d_pppg;
}; /* class AssertionPipeline */
} // namespace preprocessing
} // namespace cvc5
#endif /* CVC5__PREPROCESSING__ASSERTION_PIPELINE_H */
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