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/********************* */
/*! \file bitvector_proof.h
** \verbatim
** Top contributors (to current version):
** Liana Hadarean, Mathias Preiner, Guy Katz
** This file is part of the CVC4 project.
** Copyright (c) 2009-2018 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.\endverbatim
**
** \brief Bitvector proof base class
**
** Contains code (e.g. proof printing code) which is common to all bitvector
*proofs.
**/
#include "cvc4_private.h"
#ifndef __CVC4__BITVECTOR_PROOF_H
#define __CVC4__BITVECTOR_PROOF_H
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "expr/expr.h"
#include "proof/cnf_proof.h"
#include "proof/theory_proof.h"
#include "theory/bv/bitblast/bitblaster.h"
#include "theory/bv/theory_bv.h"
namespace CVC4 {
typedef std::unordered_set<Expr, ExprHashFunction> ExprSet;
typedef std::unordered_map<Expr, ClauseId, ExprHashFunction> ExprToClauseId;
typedef std::unordered_map<Expr, unsigned, ExprHashFunction> ExprToId;
typedef std::unordered_map<Expr, Expr, ExprHashFunction> ExprToExpr;
typedef std::unordered_map<Expr, std::string, ExprHashFunction> ExprToString;
/**
* A bitvector proof is best understood as having
*
* 1. A declaration of a "bitblasted formulas" -- boolean formulas
* that are each translations of a BV-literal (a comparison between BVs).
*
* (and a proof that each "bitblasted formula" is implied by the
* corresponding BV literal)
*
* 2. A declaration of a cnf formula equisatisfiable to the bitblasted
* formula
*
* (and a proof that each clause is implied by some bitblasted formula)
*
* 3. A proof of UNSAT from the clauses.
*
* This class is responsible for 1 & 2. The proof of UNSAT is delegated to a
* subclass.
*/
class BitVectorProof : public TheoryProof
{
protected:
BitVectorProof(theory::bv::TheoryBV* bv, TheoryProofEngine* proofEngine);
virtual ~BitVectorProof(){};
// Set of BV variables in the input. (e.g. "a" in [ a = 000 ] ^ [ a == 001 ])
ExprSet d_declarations;
// terms and formulas that are actually relevant to the proof
ExprSet d_usedBB;
ExprSet d_seenBBTerms; // terms that need to be bit-blasted
std::vector<Expr> d_bbTerms; // order of bit-blasting
/** atoms that need to be bit-blasted,
* BV-literals -> (BV-literals <=> bool formula)
* where a BV literal is a signed or unsigned comparison.
*/
ExprToExpr d_bbAtoms;
// map from Expr representing normalized lemma to ClauseId in SAT solver
ExprToClauseId d_bbConflictMap;
theory::bv::TBitblaster<Node>* d_bitblaster;
/** In an LFSC proof the manifestation of this expression bit-level
* representation will have a string name. This method returns that name.
*/
std::string getBBTermName(Expr expr);
/** A mapping from constant BV terms to identifiers that will refer to them in
* an LFSC proof, if constant-letification is enabled.
*/
std::map<Expr, std::string> d_constantLetMap;
/** Should we introduced identifiers to refer to BV constant terms? It may
* reduce the textual size of a proof!
*/
bool d_useConstantLetification;
/** Temporary storage for the set of nodes in the bitblasted formula which
* correspond to CNF variables eventually used in the proof of unsat on the
* CNF formula
*/
std::set<Node> d_atomsInBitblastingProof;
/**
* Prints out
* (a) a declaration of bit-level interpretations corresponding to bits in
* the input BV terms.
* (b) a proof that the each BV literal entails a boolean formula on
* bitof expressions.
*/
void printBitblasting(std::ostream& os, std::ostream& paren);
/**
* The proof that the bit-blasted SAT formula is correctly converted to CNF
*/
std::unique_ptr<CnfProof> d_cnfProof;
public:
void printOwnedTerm(Expr term,
std::ostream& os,
const ProofLetMap& map) override;
void printOwnedSort(Type type, std::ostream& os) override;
/**
* Populate the d_atomsInBitblastingProof member.
* See its documentation
*/
virtual void calculateAtomsInBitblastingProof() = 0;
/**
* Read the d_atomsInBitblastingProof member.
* See its documentation.
*/
const std::set<Node>* getAtomsInBitblastingProof();
void registerTermBB(Expr term);
/**
* Informs the proof that the `atom` predicate was bitblasted into the
* `atom_bb` term.
*
* The `atom` term must be a comparison of bitvectors, and the `atom_bb` term
* a boolean formula on bitof expressions
*/
void registerAtomBB(Expr atom, Expr atom_bb);
void registerTerm(Expr term) override;
/**
* This must be done before registering any terms or atoms, since the CNF
* proof must reflect the result of bitblasting those
*/
virtual void initCnfProof(prop::CnfStream* cnfStream, context::Context* ctx);
CnfProof* getCnfProof() { return d_cnfProof.get(); }
void setBitblaster(theory::bv::TBitblaster<Node>* bb);
private:
ExprToString d_exprToVariableName;
ExprToString d_assignedAliases;
std::map<std::string, std::string> d_aliasToBindDeclaration;
std::string assignAlias(Expr expr);
bool hasAlias(Expr expr);
// Functions for printing various BV terms. Helpers for BV's `printOwnedTerm`
void printConstant(Expr term, std::ostream& os);
void printOperatorNary(Expr term, std::ostream& os, const ProofLetMap& map);
void printOperatorUnary(Expr term, std::ostream& os, const ProofLetMap& map);
void printPredicate(Expr term, std::ostream& os, const ProofLetMap& map);
void printOperatorParametric(Expr term, std::ostream& os, const ProofLetMap& map);
void printBitOf(Expr term, std::ostream& os, const ProofLetMap& map);
/**
* Prints the LFSC construction of a bblast_term for `term`
*/
void printTermBitblasting(Expr term, std::ostream& os);
/**
* For a given BV-atom (a comparison), prints a proof that that comparison
* holds iff the bitblasted equivalent of it holds.
* Uses a side-condidition to do the bit-blasting.
*/
void printAtomBitblasting(Expr term, std::ostream& os, bool swap);
void printAtomBitblastingToFalse(Expr term, std::ostream& os);
void printSortDeclarations(std::ostream& os, std::ostream& paren) override;
void printTermDeclarations(std::ostream& os, std::ostream& paren) override;
void printDeferredDeclarations(std::ostream& os,
std::ostream& paren) override;
void printAliasingDeclarations(std::ostream& os,
std::ostream& paren,
const ProofLetMap& globalLetMap) override;
void printConstantDisequalityProof(std::ostream& os,
Expr c1,
Expr c2,
const ProofLetMap& globalLetMap) override;
void printRewriteProof(std::ostream& os,
const Node& n1,
const Node& n2) override;
};
}/* CVC4 namespace */
#endif /* __CVC4__BITVECTOR__PROOF_H */
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