introduce sat-smt-solver

in an iteration of inc-sat-solver introduce sat-smt-solver to allow incremental pre-processing.
The aim is to allow incrementally handling formulas while at the same time retaining the main benefits of global in/pre-processing that change models. Previous incremental solving capabilities have been limited to use pre-processing that does not require model conversion.

src/sat/sat_solver/CMakeLists.txt

@@ -2,6 +2,7 @@ z3_add_component(sat_solver
   SOURCES
     inc_sat_solver.cpp
     sat_smt_preprocess.cpp
+    sat_smt_solver.cpp
   COMPONENT_DEPENDENCIES
     aig_tactic
     arith_tactics

src/sat/sat_solver/sat_smt_solver.cpp

@@ -0,0 +1,774 @@
+/*++
+Copyright (c) 2014 Microsoft Corporation
+
+Module Name:
+
+    sat_smt_solver.cpp
+
+Abstract:
+
+    incremental solver based on SAT core.
+    It uses the ast/simplifiers to allow incremental pre-processing that 
+    produce model converters.    
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2022-11-28
+
+Notes:
+
+ - proper handling of dependencies + pre-processing 
+   - literals used in dependencies should not be eliminated by pre-processing routines
+     This has to be enforced.
+ - add translation for preprocess state.
+   - If the pre-processors are stateful, they need to be properly translated.
+ - add back get_consequences, maybe or just have them handled by inc_sat_solver
+   - could also port the layered solver used by smtfd and used by get_consequences to simplifiers
+
+ - port various pre-processing to simplifiers
+   - qe-lite, fm-elimination, ite-lifting, other from asserted_formulas
+
+--*/
+
+
+#include "util/gparams.h"
+#include "ast/ast_pp.h"
+#include "ast/ast_translation.h"
+#include "ast/ast_util.h"
+#include "solver/solver.h"
+#include "solver/parallel_params.hpp"
+#include "solver/parallel_tactic.h"
+#include "model/model_smt2_pp.h"
+#include "model/model_evaluator.h"
+#include "sat/sat_solver.h"
+#include "sat/sat_solver/sat_smt_preprocess.h"
+#include "sat/sat_params.hpp"
+#include "sat/smt/euf_solver.h"
+#include "sat/tactic/goal2sat.h"
+#include "sat/tactic/sat2goal.h"
+#include "sat/tactic/sat_tactic.h"
+#include "sat/sat_simplifier_params.hpp"
+
+// incremental SAT solver.
+class sat_smt_solver : public solver {
+
+    struct dep_expr_state : public dependent_expr_state {
+        sat_smt_solver& s;
+        model_reconstruction_trail m_reconstruction_trail;
+        dep_expr_state(sat_smt_solver& s):s(s), m_reconstruction_trail(s.m, m_trail) {}
+        ~dep_expr_state() override {}
+        virtual unsigned size() const override { return s.m_fmls.size(); }
+        dependent_expr const& operator[](unsigned i) override { return s.m_fmls[i]; }
+        void update(unsigned i, dependent_expr const& j) override { s.m_fmls[i] = j; }
+        void add(dependent_expr const& j) override { s.m_fmls.push_back(j); }
+        bool inconsistent() override { return s.m_solver.inconsistent(); }
+        model_reconstruction_trail& model_trail() override { return m_reconstruction_trail; }
+        void append(generic_model_converter& mc) { model_trail().append(mc); }
+        void replay(unsigned qhead) { m_reconstruction_trail.replay(qhead, *this); }
+    };
+
+    struct dependency2assumptions {
+        ast_manager&                m;
+        trail_stack&                m_trail;
+        expr_ref_vector             m_refs;
+        obj_map<expr, expr*>        m_dep2orig; // map original dependency to uninterpeted literal
+
+        u_map<expr*>                m_lit2dep;  // map from literal assumption to original expression
+        obj_map<expr, sat::literal> m_dep2lit;  // map uninterpreted literal to sat literal
+        sat::literal_vector         m_literals;
+        uint_set                    m_seen;
+
+        dependency2assumptions(ast_manager& m, trail_stack& t):
+            m(m),
+            m_trail(t),
+            m_refs(m)
+        {}
+
+        void reset() {
+            m_seen.reset();
+            m_literals.reset();
+            m_dep2lit.reset();
+            m_lit2dep.reset();
+        }
+
+        // inserted incrementally
+        void insert(expr* orig, expr* lit) {
+            m_trail.push(restore_vector(m_refs));
+            m_trail.push(insert_obj_map(m_dep2orig, lit));
+            m_refs.push_back(lit);
+            m_refs.push_back(orig);
+            m_dep2orig.insert(lit, orig);
+        }
+
+        // inserted on every check-sat
+        void insert(expr* dep, sat::literal lit) {
+            if (m_seen.contains(lit.index()))
+                return;
+            m_seen.insert(lit.index());
+            m_literals.push_back(lit);
+            m_dep2lit.insert(dep, lit);
+            m_lit2dep.insert(lit.index(), dep);
+        }
+
+        expr* lit2orig(sat::literal lit) {
+            expr* e = m_lit2dep[lit.index()];
+            m_dep2orig.find(e, e);
+            return e;
+        }
+
+        void copy(ast_translation& tr, dependency2assumptions const& src) {
+            for (auto const& [k, v] : src.m_dep2orig)
+                m_dep2orig.insert(tr(k), tr(v));            
+        }
+    };
+    
+    mutable sat::solver         m_solver;
+    params_ref                  m_params;
+    vector<dependent_expr>      m_fmls;
+    dep_expr_state              m_preprocess_state;
+    seq_simplifier              m_preprocess;
+    trail_stack&                m_trail;
+    dependency2assumptions      m_dep;
+    goal2sat                    m_goal2sat;
+    expr_ref_vector             m_assumptions, m_core, m_ors, m_aux_fmls;
+    atom2bool_var               m_map;
+    generic_model_converter_ref m_mc;
+    unsigned                    m_mc_size = 0;
+    mutable model_converter_ref m_cached_mc;
+    mutable ref<sat2goal::mc>   m_sat_mc;
+    std::string                 m_unknown = "no reason given";
+    // access formulas after they have been pre-processed and handled by the sat solver.
+    // this allows to access the internal state of the SAT solver and carry on partial results.
+    bool                        m_internalized_converted = false; // have internalized formulas been converted back
+    expr_ref_vector             m_internalized_fmls;      // formulas in internalized format
+
+    bool is_internalized() const { return m_preprocess.qhead() == m_fmls.size(); }
+    
+public:
+    sat_smt_solver(ast_manager& m, params_ref const& p):
+        solver(m),
+        m_preprocess_state(*this),
+        m_preprocess(m, p, m_preprocess_state),
+        m_trail(m_preprocess_state.m_trail),
+        m_dep(m, m_trail),
+        m_solver(p, m.limit()),
+        m_assumptions(m),
+        m_core(m),
+        m_ors(m),
+        m_aux_fmls(m),
+        m_map(m),
+        m_internalized_fmls(m) {
+        updt_params(p);
+        init_preprocess();
+        m_solver.set_incremental(true);
+        m_mc = alloc(generic_model_converter, m, "sat-smt-solver");
+    }
+
+    solver* translate(ast_manager& dst_m, params_ref const& p) override {
+        if (m_trail.get_num_scopes() > 0)
+            throw default_exception("Cannot translate sat solver at non-base level");
+
+        ast_translation tr(m, dst_m);
+        m_solver.pop_to_base_level();
+        sat_smt_solver* result = alloc(sat_smt_solver, dst_m, p);
+        auto* ext = get_euf();
+        if (ext) {
+            auto& si = result->m_goal2sat.si(dst_m, m_params, result->m_solver, result->m_map, result->m_dep.m_dep2lit, true);
+            euf::solver::scoped_set_translate st(*ext, dst_m, si);  
+            result->m_solver.copy(m_solver);
+        }
+        else {
+            result->m_solver.copy(m_solver);
+        }
+        // TODO: copy preprocess state        
+        for (auto const& [k, v] : m_dep.m_dep2orig) result->m_dep.insert(tr(v), tr(k));
+        for (dependent_expr const& f : m_fmls) result->m_fmls.push_back(dependent_expr(tr, f));
+        for (expr* f : m_assumptions) result->m_assumptions.push_back(tr(f));
+        for (auto & kv : m_map) result->m_map.insert(tr(kv.m_key), kv.m_value);
+        for (expr* f : m_internalized_fmls) result->m_internalized_fmls.push_back(tr(f));
+        if (m_mc) result->m_mc = dynamic_cast<generic_model_converter*>(m_mc->translate(tr));
+        result->m_dep.copy(tr, m_dep);
+        result->m_mc_size = m_mc_size;
+        if (m_sat_mc) result->m_sat_mc = dynamic_cast<sat2goal::mc*>(m_sat_mc->translate(tr));
+        result->m_internalized_converted = m_internalized_converted;
+        return result;
+    }
+
+    void set_progress_callback(progress_callback * callback) override {}
+
+    void init_check_sat() {
+        m_solver.pop_to_base_level();
+        m_core.reset();
+        m_dep.reset();
+        m_cached_mc = nullptr;
+        init_reason_unknown();
+        m_internalized_converted = false;
+    }
+
+    lbool check_sat_core(unsigned sz, expr * const * _assumptions) override {
+        init_check_sat();
+
+        if (m_solver.inconsistent())
+            return l_false;
+
+        expr_ref_vector assumptions(m);
+        for (unsigned i = 0; i < sz; ++i)
+            assumptions.push_back(ensure_literal(_assumptions[i]));
+        TRACE("sat", tout << _assumptions << "\n";);
+        lbool r = internalize_formulas();
+        if (r != l_true)
+            return r;
+
+        internalize_assumptions(assumptions);
+        
+        try {
+            r = m_solver.check(m_dep.m_literals);
+        }
+        catch (z3_exception& ex) {
+            IF_VERBOSE(1, verbose_stream() << "exception: " << ex.msg() << "\n";);
+            if (m.inc()) {
+                set_reason_unknown(std::string("(sat.giveup ") + ex.msg() + ')');
+                return l_undef;
+            }
+            r = l_undef;            
+        }
+        switch (r) {
+        case l_true:
+            check_assumptions();
+            break;
+        case l_false:
+            extract_core();
+            break;
+        default:
+            set_reason_unknown(m_solver.get_reason_unknown());
+            break;
+        }
+        return r;
+    }
+
+    void push() override {
+        try {
+            internalize_formulas();
+        }
+        catch (...) {
+            push_internal();
+            throw;
+        }
+        push_internal();
+    }
+
+    void push_internal() {   
+        m_trail.push_scope();
+        m_solver.user_push();
+        m_goal2sat.user_push();
+        m_map.push();
+        m_preprocess_state.push();
+        m_preprocess.push();
+    }
+
+    void pop(unsigned n) override {
+        if (n > m_trail.get_num_scopes())     // allow inc_sat_solver to
+            n = m_trail.get_num_scopes();     // take over for another solver.       
+
+        m_preprocess.pop(n);
+        m_preprocess_state.pop(n);
+        m_map.pop(n);
+        m_goal2sat.user_pop(n);
+        m_solver.user_pop(n);
+        m_trail.pop_scope(n);
+        m_mc->shrink(m_mc_size);
+    }
+
+    void set_phase(expr* e) override { 
+        bool is_not = m.is_not(e, e);
+        sat::bool_var b = m_map.to_bool_var(e);
+        if (b != sat::null_bool_var)
+            m_solver.set_phase(sat::literal(b, is_not));
+    }
+
+    class sat_phase : public phase, public sat::literal_vector {};
+
+    phase* get_phase() override { 
+        sat_phase* p = alloc(sat_phase);
+        for (unsigned v = m_solver.num_vars(); v-- > 0; ) 
+            p->push_back(sat::literal(v, !m_solver.get_phase(v)));
+        return p;
+    }
+    
+    void set_phase(phase* p) override { 
+        for (auto lit : *static_cast<sat_phase*>(p))
+            m_solver.set_phase(lit);
+    }
+    
+    void move_to_front(expr* e) override { 
+        m.is_not(e, e);
+        sat::bool_var b = m_map.to_bool_var(e);
+        if (b != sat::null_bool_var)
+            m_solver.move_to_front(b);
+    }
+
+    unsigned get_scope_level() const override {
+        return m_trail.get_num_scopes();        
+    }
+
+    bool is_literal(expr* a) const {
+        m.is_not(a, a);
+        return is_uninterp_const(a);
+    }
+
+    /*
+    * Ensure dependencies are literals so that pre-processing can apply to them.
+    */
+    expr* ensure_literal(expr* a) {
+        if (is_literal(a))
+            return a;
+        expr* new_dep = m.mk_fresh_const("dep", m.mk_bool_sort());
+        expr* fml = m.mk_iff(new_dep, a);
+        m_fmls.push_back(dependent_expr(m, fml, nullptr));
+        m_dep.insert(a, new_dep);
+        return new_dep;
+    }
+
+    void assert_expr_core2(expr * t, expr * a) override {
+        a = ensure_literal(a);
+        m_fmls.push_back(dependent_expr(m, t, m.mk_leaf(a)));
+    }
+
+    void assert_expr_core(expr * t) override {
+        m_fmls.push_back(dependent_expr(m, t, nullptr));
+    }
+
+    ast_manager& get_manager() const override { return m; }
+
+    void set_produce_models(bool f) override {}
+    
+    void collect_param_descrs(param_descrs & r) override {
+        solver::collect_param_descrs(r);
+        goal2sat::collect_param_descrs(r);
+        sat::solver::collect_param_descrs(r);
+        m_preprocess.collect_param_descrs(r);
+    }
+    
+    void updt_params(params_ref const & p) override {
+        m_params.append(p);
+        sat_params sp(p);
+        m_params.set_bool("keep_cardinality_constraints", sp.cardinality_solver());
+        m_params.set_sym("pb.solver", sp.pb_solver());
+        m_solver.updt_params(m_params);
+        m_solver.set_incremental(true);
+        m_preprocess.updt_params(m_params);
+        if (sp.euf())
+            ensure_euf();
+    }
+    
+    void collect_statistics(statistics & st) const override {
+        m_preprocess.collect_statistics(st);
+        m_solver.collect_statistics(st);
+    }
+    
+    void get_unsat_core(expr_ref_vector & r) override {
+        r.reset();
+        r.append(m_core.size(), m_core.data());
+    }
+
+    void get_levels(ptr_vector<expr> const& vars, unsigned_vector& depth) override {
+        unsigned sz = vars.size();
+        depth.resize(sz);
+        for (unsigned i = 0; i < sz; ++i) {
+            auto bv = m_map.to_bool_var(vars[i]);
+            depth[i] = bv == sat::null_bool_var ? UINT_MAX : m_solver.lvl(bv);
+        }
+    }
+
+    expr_ref_vector get_trail(unsigned max_level) override {
+        expr_ref_vector result(m), lit2expr(m);
+        unsigned sz = m_solver.trail_size();
+        lit2expr.resize(m_solver.num_vars() * 2);
+        m_map.mk_inv(lit2expr);
+        for (unsigned i = 0; i < sz; ++i) {
+            sat::literal lit = m_solver.trail_literal(i);
+            if (m_solver.lvl(lit) > max_level)
+                continue;
+            expr_ref e(lit2expr.get(lit.index()), m);
+            if (e)
+                result.push_back(e);
+        }
+        return result;
+    }
+
+    proof * get_proof_core() override {
+        return nullptr;
+    }
+
+    expr_ref_vector last_cube(bool is_sat) {
+        expr_ref_vector result(m);
+        result.push_back(is_sat ? m.mk_true() : m.mk_false());
+        return result;
+    }
+
+    expr_ref_vector cube(expr_ref_vector& vs, unsigned backtrack_level) override {
+        if (!is_internalized()) {
+            lbool r = internalize_formulas();
+            if (r != l_true) {
+                IF_VERBOSE(0, verbose_stream() << "internalize produced " << r << "\n");
+                return expr_ref_vector(m);
+            }
+        }
+        convert_internalized();
+        if (m_solver.inconsistent())
+            return last_cube(false);
+        obj_hashtable<expr> _vs;
+        for (expr* v : vs)
+            _vs.insert(v);
+        sat::bool_var_vector vars;
+        for (auto& kv : m_map) 
+            if (_vs.empty() || _vs.contains(kv.m_key))
+                vars.push_back(kv.m_value);
+        sat::literal_vector lits;
+        lbool result = m_solver.cube(vars, lits, backtrack_level);
+        expr_ref_vector fmls(m);
+        expr_ref_vector lit2expr(m);
+        lit2expr.resize(m_solver.num_vars() * 2);
+        m_map.mk_inv(lit2expr);
+        for (sat::literal l : lits) {
+            expr* e = lit2expr.get(l.index());
+            SASSERT(e);
+            fmls.push_back(e);
+        }
+        vs.reset();
+        for (sat::bool_var v : vars) {
+            expr* x = lit2expr[sat::literal(v, false).index()].get();
+            if (x) 
+                vs.push_back(x);
+        }
+        switch (result) {
+        case l_true:
+            return last_cube(true);
+        case l_false: 
+            return last_cube(false);
+        default: 
+            break;
+        }
+        if (lits.empty()) 
+            set_reason_unknown(m_solver.get_reason_unknown());
+        return fmls;
+    }
+    
+
+    lbool find_mutexes(expr_ref_vector const& vars, vector<expr_ref_vector>& mutexes) override {
+        sat::literal_vector ls;
+        u_map<expr*> lit2var;
+        for (expr * e : vars) {
+            expr* atom = e;;
+            bool neg = m.is_not(e, atom);
+            sat::bool_var v = m_map.to_bool_var(atom);
+            if (v != sat::null_bool_var) {
+                sat::literal lit(v, neg);
+                ls.push_back(lit);
+                lit2var.insert(lit.index(), e);
+            }
+        }
+        vector<sat::literal_vector> ls_mutexes;
+        m_solver.find_mutexes(ls, ls_mutexes);
+        for (sat::literal_vector const& ls_mutex : ls_mutexes) {
+            expr_ref_vector mutex(m);
+            for (sat::literal l : ls_mutex) 
+                mutex.push_back(lit2var.find(l.index()));            
+            mutexes.push_back(mutex);
+        }
+        return l_true;
+    }
+
+    void init_reason_unknown() {
+        m_unknown = "no reason given";
+    }
+
+    std::string reason_unknown() const override {
+        return m_unknown;
+    }
+
+    void set_reason_unknown(char const* msg) override {
+        m_unknown = msg;
+    }
+
+    void set_reason_unknown(std::string &&msg) {
+        m_unknown = std::move(msg);
+    }
+
+    void get_labels(svector<symbol> & r) override {
+    }
+
+    unsigned get_num_assertions() const override {
+        const_cast<sat_smt_solver*>(this)->convert_internalized();
+        if (is_internalized() && m_internalized_converted)             
+            return m_internalized_fmls.size();
+        else 
+            return m_fmls.size();
+    }
+
+    expr * get_assertion(unsigned idx) const override {
+        if (is_internalized() && m_internalized_converted) 
+            return m_internalized_fmls[idx];
+        return m_fmls[idx].fml();
+    }
+
+    unsigned get_num_assumptions() const override {
+        return m_assumptions.size();
+    }
+
+    expr * get_assumption(unsigned idx) const override {
+        return m_assumptions[idx];
+    }
+
+    model_converter_ref get_model_converter() const override {
+        const_cast<sat_smt_solver*>(this)->convert_internalized();
+        if (m_cached_mc)
+            return m_cached_mc;
+        if (is_internalized() && m_internalized_converted) {            
+            if (m_sat_mc) m_sat_mc->flush_smc(m_solver, m_map);
+            m_cached_mc = concat(solver::get_model_converter().get(), m_mc.get(), m_sat_mc.get());
+            TRACE("sat", m_cached_mc->display(tout););
+            return m_cached_mc;
+        }
+        else {
+            return solver::get_model_converter();
+        }
+    }
+
+    void convert_internalized() {
+        m_solver.pop_to_base_level();
+        if (!is_internalized() && m_preprocess.qhead() > 0) 
+            internalize_formulas();        
+        if (!is_internalized() || m_internalized_converted) 
+            return;
+        sat2goal s2g;
+        m_cached_mc = nullptr;
+        goal g(m, false, true, false);
+        s2g(m_solver, m_map, m_params, g, m_sat_mc);
+        m_internalized_fmls.reset();
+        g.get_formulas(m_internalized_fmls);
+        TRACE("sat", m_solver.display(tout); tout << m_internalized_fmls << "\n";);
+        m_internalized_converted = true;
+    }
+
+    void init_preprocess() {
+        ::init_preprocess(m, m_params, m_preprocess, m_preprocess_state);
+    }
+
+    euf::solver* get_euf() {
+        return dynamic_cast<euf::solver*>(m_solver.get_extension());
+    }
+
+    void init_goal2sat() {
+        m_goal2sat.init(m, m_params, m_solver, m_map, m_dep.m_dep2lit, true);      
+    }
+
+    euf::solver* ensure_euf() {
+        init_goal2sat();        
+        return m_goal2sat.ensure_euf();
+    }
+
+    void register_on_clause(void* ctx, user_propagator::on_clause_eh_t& on_clause) override {
+        ensure_euf()->register_on_clause(ctx, on_clause);
+    }
+    
+    void user_propagate_init(
+        void*                ctx, 
+        user_propagator::push_eh_t&   push_eh,
+        user_propagator::pop_eh_t&    pop_eh,
+        user_propagator::fresh_eh_t&  fresh_eh) override {
+        ensure_euf()->user_propagate_init(ctx, push_eh, pop_eh, fresh_eh);
+    }
+        
+    void user_propagate_register_fixed(user_propagator::fixed_eh_t& fixed_eh) override {
+        ensure_euf()->user_propagate_register_fixed(fixed_eh);
+    }
+    
+    void user_propagate_register_final(user_propagator::final_eh_t& final_eh) override {
+        ensure_euf()->user_propagate_register_final(final_eh);
+    }
+    
+    void user_propagate_register_eq(user_propagator::eq_eh_t& eq_eh) override {
+        ensure_euf()->user_propagate_register_eq(eq_eh);
+    }
+    
+    void user_propagate_register_diseq(user_propagator::eq_eh_t& diseq_eh) override {
+        ensure_euf()->user_propagate_register_diseq(diseq_eh);
+    }
+    
+    void user_propagate_register_expr(expr* e) override { 
+        ensure_euf()->user_propagate_register_expr(e);
+    }
+
+    void user_propagate_register_created(user_propagator::created_eh_t& r) override {
+        ensure_euf()->user_propagate_register_created(r);
+    }
+
+private:
+
+    void add_assumption(expr* a) {
+        init_goal2sat();
+        m_dep.insert(a, m_goal2sat.internalize(a));
+    }
+
+    void internalize_assumptions(expr_ref_vector const& asms) {     
+        for (expr* a : asms)
+            add_assumption(a);
+        for (expr* a : m_assumptions)
+            add_assumption(a);
+    }
+
+    lbool internalize_formulas() {
+
+        if (is_internalized())
+            return l_true;
+
+        unsigned qhead = m_preprocess.qhead();
+        m_trail.push(restore_vector(m_assumptions));
+        m_trail.push(restore_vector(m_fmls));
+        m_trail.push(value_trail(m_mc_size));
+
+        m_internalized_converted = false;
+
+        m_preprocess_state.replay(qhead);         
+        m_preprocess.reduce();
+        m_preprocess_state.append(*m_mc);
+        m_solver.pop_to_base_level();
+        m_aux_fmls.reset();
+        for (; qhead < m_fmls.size(); ++qhead)
+            add_with_dependency(m_fmls[qhead]);
+        init_goal2sat();
+        m_goal2sat(m_aux_fmls.size(), m_aux_fmls.data());
+        if (!m_sat_mc)
+            m_sat_mc = alloc(sat2goal::mc, m);
+        m_sat_mc->flush_smc(m_solver, m_map);
+        return m.inc() ? l_true : l_undef;
+    }
+
+    ptr_vector<expr> m_deps;    
+    void add_with_dependency(dependent_expr const& de) {
+        if (!de.dep()) {
+            m_aux_fmls.push_back(de.fml());
+            return;
+        }
+        m_deps.reset();
+        m.linearize(de.dep(), m_deps);   
+        m_ors.reset();
+        m_ors.push_back(de.fml());
+        flatten_or(m_ors);
+        for (expr* d : m_deps) {
+            SASSERT(m.is_bool(d));
+            SASSERT(is_literal(d));
+            m_assumptions.push_back(d);
+            m_ors.push_back(mk_not(m, d));                
+        }
+        m_aux_fmls.push_back(mk_or(m_ors));
+    }
+
+    void extract_core() {
+        m_core.reset();
+        if (m_dep.m_literals.empty())
+            return;
+        for (sat::literal c : m_solver.get_core()) 
+            m_core.push_back(m_dep.lit2orig(c));
+        TRACE("sat",
+              tout << "core: " << m_solver.get_core() << "\n";
+              tout << "core: " << m_core << "\n";
+              m_solver.display(tout));
+    }
+
+    void check_assumptions() {
+        sat::model const& ll_m = m_solver.get_model();
+        for (auto const& [k, lit] : m_dep.m_dep2lit) {
+            if (sat::value_at(lit, ll_m) == l_true)
+                continue;
+            IF_VERBOSE(0, verbose_stream() << mk_pp(k, m) << " does not evaluate to true\n";
+            verbose_stream() << m_dep.m_literals << "\n";
+            m_solver.display_assignment(verbose_stream());
+            m_solver.display(verbose_stream()););
+            throw default_exception("bad state");
+        }
+    }
+
+    void get_model_core(model_ref & mdl) override {
+        TRACE("sat", tout << "retrieve model " << (m_solver.model_is_current()?"present":"absent") << "\n";);
+        mdl = nullptr;
+        if (!m_solver.model_is_current()) 
+            return;
+        if (m_fmls.size() > m_preprocess.qhead()) 
+            return;
+        TRACE("sat", m_solver.display_model(tout););
+        CTRACE("sat", m_sat_mc, m_sat_mc->display(tout););
+        sat::model ll_m = m_solver.get_model();
+        mdl = alloc(model, m);
+        if (m_sat_mc) 
+            (*m_sat_mc)(ll_m);
+        expr_ref_vector var2expr(m);
+        m_map.mk_var_inv(var2expr);
+        
+        for (unsigned v = 0; v < var2expr.size(); ++v) {
+            expr * n = var2expr.get(v);
+            if (!n || !is_uninterp_const(n)) {
+                continue;
+            }
+            switch (sat::value_at(v, ll_m)) {
+            case l_true:
+                mdl->register_decl(to_app(n)->get_decl(), m.mk_true());
+                break;
+            case l_false:
+                mdl->register_decl(to_app(n)->get_decl(), m.mk_false());
+                break;
+            default:
+                break;
+            }
+        }
+
+        TRACE("sat", m_solver.display(tout););
+        if (m_sat_mc) 
+            (*m_sat_mc)(mdl);
+        m_goal2sat.update_model(mdl);
+        TRACE("sat", m_mc->display(tout););
+        (*m_mc)(mdl);
+    
+        TRACE("sat", model_smt2_pp(tout, m, *mdl, 0););        
+
+        if (!gparams::get_ref().get_bool("model_validate", false)) {
+            return;
+        }
+        IF_VERBOSE(1, verbose_stream() << "Verifying solution\n";);
+        model_evaluator eval(*mdl);
+        eval.set_model_completion(true);
+        bool all_true = true;
+        for (dependent_expr const& d : m_fmls) {
+            if (has_quantifiers(d.fml()))
+                continue;
+            expr_ref tmp(m);
+            eval(d.fml(), tmp);
+            if (m.limit().is_canceled())
+                return;
+            CTRACE("sat", !m.is_true(tmp),
+                   tout << "Evaluation failed: " << mk_pp(d.fml(), m) << " to " << tmp << "\n";
+                   model_smt2_pp(tout, m, *(mdl.get()), 0););
+            if (m.is_false(tmp)) {
+                IF_VERBOSE(0, verbose_stream() << "failed to verify: " << mk_pp(d.fml(), m) << "\n");
+                IF_VERBOSE(0, verbose_stream() << "evaluated to " << tmp << "\n");
+                all_true = false;
+            }
+        }
+        if (!all_true) {
+            IF_VERBOSE(0, verbose_stream() << m_params << "\n");
+            IF_VERBOSE(0, if (m_mc) m_mc->display(verbose_stream() << "mc0\n"));
+            IF_VERBOSE(0, for (auto const& kv : m_map) verbose_stream() << mk_pp(kv.m_key, m) << " |-> " << kv.m_value << "\n");
+            exit(0);
+        }
+        else {
+            IF_VERBOSE(1, verbose_stream() << "solution verified\n");
+        }
+    }
+};
+
+
+solver* mk_sat_smt_solver(ast_manager& m, params_ref const& p) {
+    return alloc(sat_smt_solver, m, p);
+}
+

src/sat/sat_solver/sat_smt_solver.h

@@ -0,0 +1,25 @@
+/*++
+Copyright (c) 2014 Microsoft Corporation
+
+Module Name:
+
+    sat_smt_solver.h
+
+Abstract:
+
+    incremental solver based on SAT core.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2014-7-30
+
+Notes:
+
+--*/
+
+#pragma once
+
+#include "solver/solver.h"
+
+solver* mk_sat_smt_solver(ast_manager& m, params_ref const& p);
+

src/tactic/portfolio/smt_strategic_solver.cpp

@@ -40,6 +40,7 @@ Notes:
 #include "muz/fp/horn_tactic.h"
 #include "smt/smt_solver.h"
 #include "sat/sat_solver/inc_sat_solver.h"
+#include "sat/sat_solver/sat_smt_solver.h"
 #include "ast/rewriter/bv_rewriter.h"
 #include "solver/solver2tactic.h"
 #include "solver/parallel_tactic.h"