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Diffstat (limited to 'src/theory/bv/bv_sat.cpp')
-rw-r--r-- | src/theory/bv/bv_sat.cpp | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/src/theory/bv/bv_sat.cpp b/src/theory/bv/bv_sat.cpp new file mode 100644 index 000000000..22a679693 --- /dev/null +++ b/src/theory/bv/bv_sat.cpp @@ -0,0 +1,300 @@ +/********************* */ +/*! \file bv_sat.cpp + ** \verbatim + ** Original author: lianah + ** Major contributors: none + ** Minor contributors (to current version): none + ** This file is part of the CVC4 prototype. + ** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys) + ** Courant Institute of Mathematical Sciences + ** New York University + ** See the file COPYING in the top-level source directory for licensing + ** information.\endverbatim + ** + ** \brief [[ Add one-line brief description here ]] + ** + ** [[ Add lengthier description here ]] + ** + **/ + +#include "bv_sat.h" +#include "theory_bv_utils.h" +#include "theory/rewriter.h" +#include "prop/cnf_stream.h" +#include "prop/sat_module.h" + +using namespace std; + +using namespace CVC4::theory::bv::utils; +using namespace CVC4::context; +using namespace CVC4::prop; + +namespace CVC4 { +namespace theory { +namespace bv{ + + +std::string toString(Bits& bits) { + ostringstream os; + for (int i = bits.size() - 1; i >= 0; --i) { + TNode bit = bits[i]; + if (bit.getKind() == kind::CONST_BOOLEAN) { + os << (bit.getConst<bool>() ? "1" : "0"); + } else { + os << bit<< " "; + } + } + os <<"\n"; + + return os.str(); +} +/////// Bitblaster + +Bitblaster::Bitblaster(context::Context* c) : + d_termCache(), + d_bitblastedAtoms(), + d_assertedAtoms(c), + d_statistics() + { + d_satSolver = prop::SatSolverFactory::createMinisat(); + d_cnfStream = new TseitinCnfStream(d_satSolver, new NullRegistrar()); + + // initializing the bit-blasting strategies + initAtomBBStrategies(); + initTermBBStrategies(); + } + + +/** + * Bitblasts the atom, assigns it a marker literal, adding it to the SAT solver + * NOTE: duplicate clauses are not detected because of marker literal + * @param node the atom to be bitblasted + * + */ +void Bitblaster::bbAtom(TNode node) { + if (hasBBAtom(node)) { + return; + } + + // the bitblasted definition of the atom + Node atom_bb = d_atomBBStrategies[node.getKind()](node, this); + // asserting that the atom is true iff the definition holds + Node atom_definition = mkNode(kind::IFF, node, atom_bb); + // do boolean simplifications if possible + Node rewritten = Rewriter::rewrite(atom_definition); + d_cnfStream->convertAndAssert(rewritten, true, false); + d_bitblastedAtoms.insert(node); +} + + +void Bitblaster::bbTerm(TNode node, Bits& bits) { + if (hasBBTerm(node)) { + getBBTerm(node, bits); + return; + } + + d_termBBStrategies[node.getKind()] (node, bits,this); + + Assert (bits.size() == utils::getSize(node)); + cacheTermDef(node, bits); +} + +/// Public methods + +/** + * Called from preregistration bitblasts the node + * + * @param node + * + * @return + */ +void Bitblaster::bitblast(TNode node) { + TimerStat::CodeTimer codeTimer(d_statistics.d_bitblastTimer); + + /// strip the not + if (node.getKind() == kind::NOT) { + node = node[0]; + } + + if (node.getKind() == kind::EQUAL || + node.getKind() == kind::BITVECTOR_ULT || + node.getKind() == kind::BITVECTOR_SLT || + node.getKind() == kind::BITVECTOR_ULE || + node.getKind() == kind::BITVECTOR_SLE ) + { + bbAtom(node); + } + else if (node.getKind() == kind::BITVECTOR_UGT || + node.getKind() == kind::BITVECTOR_UGE || + node.getKind() == kind::BITVECTOR_SGT || + node.getKind() == kind::BITVECTOR_SGE ) + { + Unhandled(node.getKind()); + } + else + { + Bits bits; + bbTerm(node, bits); + } +} + +/** + * Asserts the clauses corresponding to the atom to the Sat Solver + * by turning on the marker literal (i.e. setting it to false) + * @param node the atom to be aserted + * + */ + +void Bitblaster::assertToSat(TNode lit) { + // strip the not + TNode atom; + if (lit.getKind() == kind::NOT) { + atom = lit[0]; + } else { + atom = lit; + } + + Assert (hasBBAtom(atom)); + SatLiteral markerLit = d_cnfStream->getLiteral(atom); + + if(lit.getKind() == kind::NOT) { + markerLit = ~markerLit; + } + + Debug("bitvector-bb") << "TheoryBV::Bitblaster::assertToSat asserting node: " << atom <<"\n"; + Debug("bitvector-bb") << "TheoryBV::Bitblaster::assertToSat with literal: " << markerLit << "\n"; + + d_assertedAtoms.push_back(markerLit); +} + +/** + * Calls the solve method for the Sat Solver. + * passing it the marker literals to be asserted + * + * @return true for sat, and false for unsat + */ + +bool Bitblaster::solve() { + return SatValTrue == d_satSolver->solve(d_assertedAtoms); +} + +void Bitblaster::getConflict(std::vector<TNode>& conflict) { + SatClause conflictClause; + d_satSolver->getUnsatCore(conflictClause); + + for (unsigned i = 0; i < conflictClause.size(); i++) { + SatLiteral lit = conflictClause[i]; + TNode atom = d_cnfStream->getNode(lit); + Node not_atom; + if (atom.getKind() == kind::NOT) { + not_atom = atom[0]; + } else { + not_atom = NodeManager::currentNM()->mkNode(kind::NOT, atom); + } + conflict.push_back(not_atom); + } +} + + +/// Helper methods + + +void Bitblaster::initAtomBBStrategies() { + for (int i = 0 ; i < kind::LAST_KIND; ++i ) { + d_atomBBStrategies[i] = UndefinedAtomBBStrategy; + } + + /// setting default bb strategies for atoms + d_atomBBStrategies [ kind::EQUAL ] = DefaultEqBB; + d_atomBBStrategies [ kind::BITVECTOR_ULT ] = DefaultUltBB; + d_atomBBStrategies [ kind::BITVECTOR_ULE ] = DefaultUleBB; + d_atomBBStrategies [ kind::BITVECTOR_UGT ] = DefaultUgtBB; + d_atomBBStrategies [ kind::BITVECTOR_UGE ] = DefaultUgeBB; + d_atomBBStrategies [ kind::BITVECTOR_SLT ] = DefaultSltBB; + d_atomBBStrategies [ kind::BITVECTOR_SLE ] = DefaultSleBB; + d_atomBBStrategies [ kind::BITVECTOR_SGT ] = DefaultSgtBB; + d_atomBBStrategies [ kind::BITVECTOR_SGE ] = DefaultSgeBB; + +} + +void Bitblaster::initTermBBStrategies() { + for (int i = 0 ; i < kind::LAST_KIND; ++i ) { + d_termBBStrategies[i] = UndefinedTermBBStrategy; + } + + /// setting default bb strategies for terms: + d_termBBStrategies [ kind::VARIABLE ] = DefaultVarBB; + d_termBBStrategies [ kind::CONST_BITVECTOR ] = DefaultConstBB; + d_termBBStrategies [ kind::BITVECTOR_NOT ] = DefaultNotBB; + d_termBBStrategies [ kind::BITVECTOR_CONCAT ] = DefaultConcatBB; + d_termBBStrategies [ kind::BITVECTOR_AND ] = DefaultAndBB; + d_termBBStrategies [ kind::BITVECTOR_OR ] = DefaultOrBB; + d_termBBStrategies [ kind::BITVECTOR_XOR ] = DefaultXorBB; + d_termBBStrategies [ kind::BITVECTOR_XNOR ] = DefaultXnorBB; + d_termBBStrategies [ kind::BITVECTOR_NAND ] = DefaultNandBB ; + d_termBBStrategies [ kind::BITVECTOR_NOR ] = DefaultNorBB; + d_termBBStrategies [ kind::BITVECTOR_COMP ] = DefaultCompBB ; + d_termBBStrategies [ kind::BITVECTOR_MULT ] = DefaultMultBB; + d_termBBStrategies [ kind::BITVECTOR_PLUS ] = DefaultPlusBB; + d_termBBStrategies [ kind::BITVECTOR_SUB ] = DefaultSubBB; + d_termBBStrategies [ kind::BITVECTOR_NEG ] = DefaultNegBB; + d_termBBStrategies [ kind::BITVECTOR_UDIV ] = DefaultUdivBB; + d_termBBStrategies [ kind::BITVECTOR_UREM ] = DefaultUremBB; + d_termBBStrategies [ kind::BITVECTOR_SDIV ] = DefaultSdivBB; + d_termBBStrategies [ kind::BITVECTOR_SREM ] = DefaultSremBB; + d_termBBStrategies [ kind::BITVECTOR_SMOD ] = DefaultSmodBB; + d_termBBStrategies [ kind::BITVECTOR_SHL ] = DefaultShlBB; + d_termBBStrategies [ kind::BITVECTOR_LSHR ] = DefaultLshrBB; + d_termBBStrategies [ kind::BITVECTOR_ASHR ] = DefaultAshrBB; + d_termBBStrategies [ kind::BITVECTOR_EXTRACT ] = DefaultExtractBB; + d_termBBStrategies [ kind::BITVECTOR_REPEAT ] = DefaultRepeatBB; + d_termBBStrategies [ kind::BITVECTOR_ZERO_EXTEND ] = DefaultZeroExtendBB; + d_termBBStrategies [ kind::BITVECTOR_SIGN_EXTEND ] = DefaultSignExtendBB; + d_termBBStrategies [ kind::BITVECTOR_ROTATE_RIGHT ] = DefaultRotateRightBB; + d_termBBStrategies [ kind::BITVECTOR_ROTATE_LEFT ] = DefaultRotateLeftBB; + +} + +bool Bitblaster::hasBBAtom(TNode atom) { + return d_bitblastedAtoms.find(atom) != d_bitblastedAtoms.end(); +} + +void Bitblaster::cacheTermDef(TNode term, Bits def) { + Assert (d_termCache.find(term) == d_termCache.end()); + d_termCache[term] = def; +} + +bool Bitblaster::hasBBTerm(TNode node) { + return d_termCache.find(node) != d_termCache.end(); +} + +void Bitblaster::getBBTerm(TNode node, Bits& bits) { + + Assert (hasBBTerm(node)); + // copy? + bits = d_termCache[node]; +} + +Bitblaster::Statistics::Statistics() : + d_numTermClauses("theory::bv::NumberOfTermSatClauses", 0), + d_numAtomClauses("theory::bv::NumberOfAtomSatClauses", 0), + d_bitblastTimer("theory::bv::BitblastTimer") +{ + StatisticsRegistry::registerStat(&d_numTermClauses); + StatisticsRegistry::registerStat(&d_numAtomClauses); + StatisticsRegistry::registerStat(&d_bitblastTimer); +} + + +Bitblaster::Statistics::~Statistics() { + StatisticsRegistry::unregisterStat(&d_numTermClauses); + StatisticsRegistry::unregisterStat(&d_numAtomClauses); + StatisticsRegistry::unregisterStat(&d_bitblastTimer); +} + + + + +} /*bv namespace */ +} /* theory namespace */ +} /* CVC4 namespace*/ |