Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/occf_tactic.cpp

@@ -0,0 +1,252 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    occf_tactic.cpp
+
+Abstract:
+
+    Put clauses in the assertion set in
+    OOC (one constraint per clause) form.
+    Constraints occuring in formulas that
+    are not clauses are ignored.
+    The formula can be put into CNF by
+    using mk_sat_preprocessor strategy.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-12-28.
+
+Revision History:
+
+--*/
+#include"tactical.h"
+#include"occf_tactic.h"
+#include"filter_model_converter.h"
+#include"cooperate.h"
+
+class occf_tactic : public tactic {
+    struct     imp {
+        ast_manager &            m;
+        volatile bool            m_cancel;
+        filter_model_converter * m_mc;
+        
+        imp(ast_manager & _m):
+            m(_m) {
+            m_cancel = false;
+        }
+
+        void set_cancel(bool f) {
+            m_cancel = f;
+        }
+
+        void checkpoint() {
+            if (m_cancel)
+                throw tactic_exception(TACTIC_CANCELED_MSG);
+            cooperate("occf");
+        }
+
+        bool is_literal(expr * t) const {
+            expr * atom;
+            return is_uninterp_const(t) || (m.is_not(t, atom) && is_uninterp_const(atom));
+        }
+        
+        bool is_constraint(expr * t) const {
+            return !is_literal(t);
+        }
+        
+        bool is_target(app * cls) {
+            SASSERT(m.is_or(cls));
+            bool found = false;
+            unsigned num = cls->get_num_args();
+            for (unsigned i = 0; i < num; i++) {
+                if (is_constraint(cls->get_arg(i))) {
+                    if (found)
+                        return true;
+                    found = true;
+                }
+            }
+            return false;
+        }
+        
+        struct bvar_info {
+            expr *   m_bvar;
+            unsigned m_gen_pos:1;
+            unsigned m_gen_neg:1;
+            bvar_info():m_bvar(0), m_gen_pos(false), m_gen_neg(false) {}
+            bvar_info(expr * var, bool sign):
+                m_bvar(var),
+                                            m_gen_pos(!sign),
+                m_gen_neg(sign) {
+            }
+        };
+        
+        typedef obj_map<expr, bvar_info> cnstr2bvar;
+        
+        expr * get_aux_lit(cnstr2bvar & c2b, expr * cnstr, goal_ref const & g) {
+            bool sign = false;
+            while (m.is_not(cnstr)) {
+                cnstr = to_app(cnstr)->get_arg(0);
+                sign  = !sign;
+            }
+            
+            cnstr2bvar::obj_map_entry * entry = c2b.find_core(cnstr);
+            if (entry == 0)
+                return 0;
+            bvar_info & info = entry->get_data().m_value;
+            if (sign) {
+                if (!info.m_gen_neg) {
+                    info.m_gen_neg = true;
+                    g->assert_expr(m.mk_or(info.m_bvar, m.mk_not(cnstr)), 0, 0);
+                }
+                return m.mk_not(info.m_bvar);
+            }
+            else {
+                if (!info.m_gen_pos) {
+                    info.m_gen_pos = true;
+                    g->assert_expr(m.mk_or(m.mk_not(info.m_bvar), cnstr), 0, 0);
+                }
+                return info.m_bvar;
+            }
+        }
+
+        expr * mk_aux_lit(cnstr2bvar & c2b, expr * cnstr, bool produce_models, goal_ref const & g) {
+            bool sign = false;
+            while (m.is_not(cnstr)) {
+                cnstr = to_app(cnstr)->get_arg(0);
+                sign  = !sign;
+            }
+            
+            SASSERT(!c2b.contains(cnstr));
+            expr * bvar = m.mk_fresh_const(0, m.mk_bool_sort());
+            if (produce_models)
+                m_mc->insert(to_app(bvar)->get_decl());
+            c2b.insert(cnstr, bvar_info(bvar, sign));
+            if (sign) {
+                g->assert_expr(m.mk_or(bvar, m.mk_not(cnstr)), 0, 0);
+                return m.mk_not(bvar);
+            }
+            else {
+                g->assert_expr(m.mk_or(m.mk_not(bvar), cnstr), 0, 0);
+                return bvar;
+            }
+        }
+        
+        void operator()(goal_ref const & g, 
+                        goal_ref_buffer & result, 
+                        model_converter_ref & mc, 
+                        proof_converter_ref & pc,
+                        expr_dependency_ref & core) {
+            SASSERT(g->is_well_sorted());
+            mc = 0; pc = 0; core = 0;
+
+            fail_if_proof_generation("occf", g);
+
+            bool produce_models = g->models_enabled();
+            tactic_report report("occf", *g);
+            
+            m_mc = 0;
+            
+            ptr_vector<expr> new_lits;
+            
+            cnstr2bvar c2b;
+            
+            unsigned sz = g->size();
+            for (unsigned i = 0; i < sz; i++) {
+                checkpoint();
+                expr * f = g->form(i);
+                expr_dependency * d = g->dep(i);
+                if (!m.is_or(f))
+                    continue;
+                app * cls = to_app(f);
+                if (!is_target(cls))
+                    continue;
+                if (produce_models && !m_mc) {
+                    m_mc = alloc(filter_model_converter, m);
+                    mc = m_mc;
+                }
+                expr * keep = 0;
+                new_lits.reset();
+                unsigned num = cls->get_num_args();
+                for (unsigned j = 0; j < num; j++) {
+                    expr * l = cls->get_arg(j);
+                    if (is_constraint(l)) {
+                        expr * new_l = get_aux_lit(c2b, l, g);
+                        if (new_l != 0) {
+                            new_lits.push_back(new_l);
+                        }
+                        else if (keep == 0) {
+                            keep = l;
+                        }
+                        else {
+                            new_l = mk_aux_lit(c2b, l, produce_models, g);
+                            new_lits.push_back(new_l);
+                        }
+                    }
+                    else {
+                        new_lits.push_back(l);
+                    }
+                }
+                if (keep != 0)
+                    new_lits.push_back(keep);
+                g->update(i, m.mk_or(new_lits.size(), new_lits.c_ptr()), 0, d);
+            }
+            g->inc_depth();
+            result.push_back(g.get());
+            TRACE("occf", g->display(tout););
+            SASSERT(g->is_well_sorted());
+        }
+    };
+    
+    imp *      m_imp;
+public:
+    occf_tactic(ast_manager & m) {
+        m_imp = alloc(imp, m);
+    }
+
+    virtual tactic * translate(ast_manager & m) {
+        return alloc(occf_tactic, m);
+    }
+        
+    virtual ~occf_tactic() {
+        dealloc(m_imp);
+    }
+
+    virtual void updt_params(params_ref const & p) {}
+    virtual void collect_param_descrs(param_descrs & r) {}
+    
+    virtual void operator()(goal_ref const & in, 
+                            goal_ref_buffer & result, 
+                            model_converter_ref & mc, 
+                            proof_converter_ref & pc,
+                            expr_dependency_ref & core) {
+        (*m_imp)(in, result, mc, pc, core);
+    }
+    
+    virtual void cleanup() {
+        ast_manager & m = m_imp->m;
+        imp * d = m_imp;
+        #pragma omp critical (tactic_cancel)
+        {
+            m_imp = 0;
+        }
+        dealloc(d);
+        d = alloc(imp, m);
+        #pragma omp critical (tactic_cancel)
+        {
+            m_imp = d;
+        }
+    }
+    
+protected:
+    virtual void set_cancel(bool f) {
+        if (m_imp)
+            m_imp->set_cancel(f);
+    }
+};
+
+tactic * mk_occf_tactic(ast_manager & m, params_ref const & p) {
+    return clean(alloc(occf_tactic, m));
+}
+