adding stubs

src/sat/smt/CMakeLists.txt

@@ -37,6 +37,7 @@ z3_add_component(sat_smt
     q_model_fixer.cpp
     q_queue.cpp
     q_solver.cpp
+    recfun_solver.cpp
     sat_dual_solver.cpp
     sat_th.cpp
     user_solver.cpp

src/sat/smt/recfun_solver.cpp

@@ -0,0 +1,116 @@
+/*++
+Copyright (c) 2020 Microsoft Corporation
+
+Module Name:
+
+    recfun_solver.cpp
+
+Abstract:
+
+    Recursive function solver plugin
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-02-09
+
+--*/
+
+#include "sat/smt/recfun_solver.h"
+#include "sat/smt/euf_solver.h"
+
+
+
+namespace recfun {
+
+
+    solver::solver(euf::solver& ctx):
+        th_euf_solver(ctx, symbol("recfun"), ctx.get_manager().mk_family_id("recfun")),
+        m_plugin(*reinterpret_cast<recfun::decl::plugin*>(m.get_plugin(ctx.get_manager().mk_family_id("recfun")))),
+        m_util(m_plugin.u()), 
+        m_disabled_guards(m),
+        m_enabled_guards(m),
+        m_preds(m),
+        m_num_rounds(0),
+        m_q_case_expand(), 
+        m_q_body_expand() {
+        m_num_rounds = 0;
+    }    
+
+    solver::~solver() {
+        reset();
+    }
+
+    void solver::reset() {
+        reset_queues();   
+        m_stats.reset();
+        m_disabled_guards.reset();
+        m_enabled_guards.reset();
+        m_q_guards.reset();
+        for (auto & kv : m_guard2pending) 
+            dealloc(kv.m_value);
+        m_guard2pending.reset();
+    }
+
+    void solver::reset_queues() {
+        for (auto* e : m_q_case_expand) {
+            dealloc(e);
+        }
+        m_q_case_expand.reset();
+        for (auto* e : m_q_body_expand) {
+            dealloc(e);
+        }
+        m_q_body_expand.reset();
+        m_q_clauses.clear();        
+    }
+
+    void solver::get_antecedents(sat::literal l, sat::ext_justification_idx idx, sat::literal_vector& r, bool probing) {
+
+    }
+
+    void solver::asserted(sat::literal l) {
+
+    }
+
+    sat::check_result solver::check() {
+        return sat::check_result::CR_DONE;
+    }
+
+    std::ostream& solver::display(std::ostream& out) const {
+        return out;
+    }
+
+    std::ostream& solver::display_constraint(std::ostream& out, sat::ext_constraint_idx idx) const {
+        return out;
+    }
+
+    void solver::collect_statistics(statistics& st) const {
+
+    }
+
+    euf::th_solver* solver::clone(euf::solver& ctx) {
+        return nullptr;
+    }
+
+    bool solver::unit_propagate() {
+        return false;
+    }
+
+    sat::literal solver::internalize(expr* e, bool sign, bool root, bool learned) {
+        return sat::null_literal;
+    }
+
+    euf::theory_var solver::mk_var(euf::enode* n) {
+        return euf::null_theory_var;
+    }
+
+    void solver::init_search() {
+
+    }
+    
+    void solver::finalize_model(model& mdl) {
+        
+    }
+
+
+    
+}

src/sat/smt/recfun_solver.h

@@ -0,0 +1,166 @@
+/*++
+Copyright (c) 2020 Microsoft Corporation
+
+Module Name:
+
+    recfun_solver.h
+
+Abstract:
+
+    Recursive function solver plugin
+
+Author:
+
+    Simon Cruanes December 2017
+    Nikolaj Bjorner (nbjorner) 2021-02-09
+
+--*/
+#pragma once
+
+#include "ast/recfun_decl_plugin.h"
+#include "ast/ast_trail.h"
+#include "sat/smt/sat_th.h"
+
+
+namespace euf {
+    class solver;
+}
+
+namespace recfun {
+
+    class solver : public euf::th_euf_solver {
+
+        struct stats {
+            unsigned m_case_expansions, m_body_expansions, m_macro_expansions;
+            void reset() { memset(this, 0, sizeof(stats)); }
+            stats() { reset(); }
+        };
+
+        // one case-expansion of `f(t1...tn)`
+        struct case_expansion {
+            app *              m_lhs; // the term to expand
+            recfun::def *       m_def;
+            ptr_vector<expr>    m_args;
+            case_expansion(recfun::util& u, app * n) : 
+            m_lhs(n), m_def(nullptr), m_args()  {
+                SASSERT(u.is_defined(n));
+                func_decl * d = n->get_decl();
+                m_def = &u.get_def(d);
+                m_args.append(n->get_num_args(), n->get_args());
+            }
+            case_expansion(case_expansion const & from)
+                : m_lhs(from.m_lhs),
+                  m_def(from.m_def),
+                  m_args(from.m_args) {}
+            case_expansion(case_expansion && from)
+                : m_lhs(from.m_lhs),
+                  m_def(from.m_def),
+                  m_args(std::move(from.m_args)) {}
+        };
+
+        struct pp_case_expansion {
+            case_expansion & e;
+            ast_manager & m;
+            pp_case_expansion(case_expansion & e, ast_manager & m) : e(e), m(m) {}
+        };
+
+        friend std::ostream& operator<<(std::ostream&, pp_case_expansion const &);
+
+        // one body-expansion of `f(t1...tn)` using a `C_f_i(t1...tn)`
+        struct body_expansion {
+            app*                     m_pred;
+            recfun::case_def const * m_cdef;
+            ptr_vector<expr>         m_args;
+
+            body_expansion(recfun::util& u, app * n) : m_pred(n), m_cdef(nullptr), m_args() {
+                m_cdef = &u.get_case_def(n);
+                m_args.append(n->get_num_args(), n->get_args());
+            }
+            body_expansion(app* pred, recfun::case_def const & d, ptr_vector<expr> & args) : 
+                m_pred(pred), m_cdef(&d), m_args(args) {}
+            body_expansion(body_expansion const & from): 
+                m_pred(from.m_pred), m_cdef(from.m_cdef), m_args(from.m_args) {}
+            body_expansion(body_expansion && from) : 
+                m_pred(from.m_pred), m_cdef(from.m_cdef), m_args(std::move(from.m_args)) {}
+        };
+
+        struct pp_body_expansion {
+            body_expansion & e;
+            ast_manager & m;
+            pp_body_expansion(body_expansion & e, ast_manager & m) : e(e), m(m) {}
+        };
+
+        friend std::ostream& operator<<(std::ostream&, pp_body_expansion const &);
+        
+        recfun::decl::plugin&   m_plugin;
+        recfun::util&           m_util;
+        stats                   m_stats;
+
+        // book-keeping for depth of predicates
+        expr_ref_vector          m_disabled_guards;
+        expr_ref_vector          m_enabled_guards;
+        obj_map<expr, expr_ref_vector*> m_guard2pending;
+        obj_map<expr, unsigned>  m_pred_depth;
+        expr_ref_vector          m_preds;
+        unsigned_vector          m_preds_lim;
+        unsigned                 m_num_rounds;
+
+        ptr_vector<case_expansion>  m_q_case_expand;
+        ptr_vector<body_expansion>  m_q_body_expand;
+        vector<sat::literal_vector> m_q_clauses;
+        ptr_vector<expr>            m_q_guards;
+
+        bool is_enabled_guard(expr* guard) { expr_ref ng(m.mk_not(guard), m); return m_enabled_guards.contains(ng); }
+        bool is_disabled_guard(expr* guard) { return m_disabled_guards.contains(guard); }
+
+        recfun::util & u() const { return m_util; }
+        bool is_defined(expr * f) const { return u().is_defined(f); }
+        bool is_case_pred(expr * f) const { return u().is_case_pred(f); }
+
+        bool is_defined(euf::enode * e) const { return is_defined(e->get_expr()); }
+        bool is_case_pred(euf::enode * e) const { return is_case_pred(e->get_expr()); }
+
+        void activate_guard(expr* guard, expr_ref_vector const& guards);
+
+        void reset_queues();
+        expr_ref apply_args(unsigned depth, recfun::vars const & vars, ptr_vector<expr> const & args, expr * e); //!< substitute variables by args
+        void assert_macro_axiom(case_expansion & e);
+        void assert_case_axioms(case_expansion & e);
+        void assert_body_axiom(body_expansion & e);
+        sat::literal mk_literal(expr* e);
+
+        void add_induction_lemmas(unsigned depth);
+        void disable_guard(expr* guard, expr_ref_vector const& guards);
+        unsigned get_depth(expr* e);
+        void set_depth(unsigned d, expr* e);
+        void set_depth_rec(unsigned d, expr* e);
+        
+        sat::literal mk_eq_lit(expr* l, expr* r);
+        bool is_standard_order(recfun::vars const& vars) const { 
+            return vars.empty() || vars[vars.size()-1]->get_idx() == 0;
+        }
+
+        void reset();
+
+    public:
+
+        solver(euf::solver& ctx);
+        ~solver() override;
+        bool is_external(sat::bool_var v) override { return false; }
+        void get_antecedents(sat::literal l, sat::ext_justification_idx idx, sat::literal_vector& r, bool probing) override;
+        void asserted(sat::literal l) override;
+        sat::check_result check() override;
+        std::ostream& display(std::ostream& out) const override;
+        std::ostream& display_justification(std::ostream& out, sat::ext_justification_idx idx) const override { return display_constraint(out, idx); }
+        std::ostream& display_constraint(std::ostream& out, sat::ext_constraint_idx idx) const override;
+        void collect_statistics(statistics& st) const override;
+        euf::th_solver* clone(euf::solver& ctx) override;
+        bool unit_propagate() override;
+        sat::literal internalize(expr* e, bool sign, bool root, bool learned) override;
+        void internalize(expr* e, bool redundant) override { UNREACHABLE(); }
+        euf::theory_var mk_var(euf::enode* n) override;
+        void init_search() override;
+        void finalize_model(model& mdl) override;
+        bool is_shared(euf::theory_var v) const override { return true; }
+    };
+}