Add basic Sine Qua Non filtering

contrib/cmake/src/tactic/CMakeLists.txt

@@ -12,6 +12,7 @@ z3_add_component(tactic
     probe.cpp
     proof_converter.cpp
     replace_proof_converter.cpp
+    sine_filter.cpp
     tactical.cpp
     tactic.cpp
   COMPONENT_DEPENDENCIES

src/tactic/sine_filter.cpp

@@ -0,0 +1,252 @@
+/*++
+Copyright (c) 2016 Microsoft Corporation
+
+Module Name:
+
+    sine_filter.cpp
+
+Abstract:
+
+    Tactic that performs Sine Qua Non premise selection
+
+Revision History:
+--*/
+
+#include "sine_filter.h"
+#include "tactical.h"
+#include "filter_model_converter.h"
+#include "datatype_decl_plugin.h"
+#include "rewriter_def.h"
+#include "filter_model_converter.h"
+#include "extension_model_converter.h"
+#include "var_subst.h"
+#include "ast_util.h"
+#include "obj_pair_hashtable.h"
+
+#if 0
+TODO documentation here
+#endif
+
+
+class sine_tactic : public tactic {
+
+    ast_manager&  m;
+    params_ref    m_params;
+    datatype_util m_dt;
+    ref<extension_model_converter> m_ext;
+    ref<filter_model_converter>    m_filter;
+    unsigned                       m_num_transformed;
+
+public:
+
+    sine_tactic(ast_manager& m, params_ref const& p): 
+        m(m), m_params(p), m_dt(m) {}
+    
+    virtual tactic * translate(ast_manager & m) {
+        return alloc(sine_tactic, m, m_params);
+    }
+
+    virtual void updt_params(params_ref const & p) {
+    }
+
+    virtual void collect_param_descrs(param_descrs & r) {
+    }
+
+    virtual void operator()(goal_ref const & g,
+                            goal_ref_buffer & result,
+                            model_converter_ref & mc,
+                            proof_converter_ref & pc,
+                            expr_dependency_ref & core) {
+        mc = 0; pc = 0; core = 0;
+
+        TRACE("sine", g->display(tout););
+        TRACE("sine", tout << g->size(););
+        ptr_vector<expr> new_forms;
+        filter_expressions(g, new_forms);
+        TRACE("sine", tout << new_forms.size(););
+        g->reset();
+        for (unsigned i = 0; i < new_forms.size(); i++) {
+          g->assert_expr(new_forms.get(i), 0, 0);
+        }
+        g->inc_depth();
+        g->updt_prec(goal::OVER);
+        result.push_back(g.get());
+        TRACE("sine", result[0]->display(tout););
+        SASSERT(g->is_well_sorted());
+        filter_model_converter * fmc = alloc(filter_model_converter, m);
+        mc = fmc;
+    }
+    
+    virtual void cleanup() {
+    }
+
+private:
+
+  // is this a user-defined symbol name?
+  bool is_name(func_decl * f) {
+    return f->get_family_id() < 0;
+  }
+
+  typedef std::pair<expr*,expr*> t_work_item;
+
+  t_work_item work_item(expr *e, expr *root) {
+    return std::pair<expr*, expr*>(e, root);
+  }
+
+  void find_constants(expr *e, obj_hashtable<func_decl> &consts) {
+    ptr_vector<expr> stack;
+    stack.push_back(e);
+    expr *curr;
+    while (!stack.empty()) {
+      curr = stack.back();
+      stack.pop_back();
+      if (is_app(curr)) {
+        app *a = to_app(curr);
+        func_decl *f = a->get_decl();
+        if (is_name(f) && !consts.contains(f)) {
+          consts.insert(f);
+        }
+      }
+    }
+  }
+
+  bool quantifier_matches(quantifier *q,
+                          obj_hashtable<func_decl> const & consts,
+                          ptr_vector<func_decl> & next_consts) {
+    TRACE("sine", tout << "size of consts is "; tout << consts.size(); tout << "\n";);
+    for (obj_hashtable<func_decl>::iterator constit = consts.begin(), constend = consts.end(); constit != constend; constit++) {
+      TRACE("sine", tout << *constit; tout << "\n";);
+    }
+    bool matched = false;
+    for (int i = 0; i < q->get_num_patterns(); i++) {
+      bool p_matched = true;
+      vector<expr *> stack;
+      expr *curr;
+      // patterns are wrapped with "pattern"
+      stack.push_back(to_app(q->get_pattern(i))->get_arg(0));
+      while (!stack.empty()) {
+        curr = stack.back();
+        stack.pop_back();
+        if (is_app(curr)) {
+          app *a = to_app(curr);
+          func_decl *f = a->get_decl();
+          if (!consts.contains(f)) {
+            TRACE("sine", tout << f; tout << "\n";);
+            p_matched = false;
+            next_consts.push_back(f);
+            break;
+          }
+          for (int j = 0; j < a->get_num_args(); j++) {
+            stack.push_back(a->get_arg(j));
+          }
+        }
+      }
+      if (p_matched) {
+        matched = true;
+        break;
+      }
+    }
+    return matched;
+  }
+  
+  void filter_expressions(goal_ref const & g, ptr_vector<expr> & new_exprs) {
+    obj_map<func_decl, obj_hashtable<expr> > const2exp;
+    obj_map<expr, obj_hashtable<func_decl> > exp2const;
+    obj_map<func_decl, obj_pair_hashtable<expr, expr> > const2quantifier;
+    obj_hashtable<func_decl> consts;
+    vector<t_work_item> stack;
+    for (int i = 0; i < g->size(); i++) {
+      stack.push_back(work_item(g->form(i), g->form(i)));
+    }
+    t_work_item curr;
+    while (!stack.empty()) {
+      curr = stack.back();
+      stack.pop_back();
+      if (is_app(curr.first)) {
+        app *a = to_app(curr.first);
+        func_decl *f = a->get_decl();
+        if (is_name(f)) {
+          if (!consts.contains(f)) {
+            consts.insert(f);
+            if (const2quantifier.contains(f)) {
+              for (obj_pair_hashtable<expr, expr>::iterator it = const2quantifier[f].begin(), end = const2quantifier[f].end(); it != end; it++) {
+                stack.push_back(*it);
+              }
+              const2quantifier.remove(f);
+            }
+          }
+          if (!const2exp.contains(f)) {
+            const2exp.insert(f, obj_hashtable<expr>());
+          }
+          if (!const2exp[f].contains(curr.second)) {
+            const2exp[f].insert(curr.second);
+          }
+          if (!exp2const.contains(curr.second)) {
+            exp2const.insert(curr.second, obj_hashtable<func_decl>());
+          }
+          if (!exp2const[curr.second].contains(f)) {
+            exp2const[curr.second].insert(f);
+          }
+        }
+        for (int i = 0; i < a->get_num_args(); i++) {
+          stack.push_back(work_item(a->get_arg(i), curr.second));
+        }
+      }
+      else if (is_quantifier(curr.first)) {
+        quantifier *q = to_quantifier(curr.first);
+        if (q->is_forall()) {
+          if (q->has_patterns()) {
+            ptr_vector<func_decl> next_consts;
+            if (quantifier_matches(q, consts, next_consts)) {
+              stack.push_back(work_item(q->get_expr(), curr.second));
+            }
+            else {
+              for (unsigned i = 0; i < next_consts.size(); i++) {
+                func_decl *c = next_consts.get(i);
+                if (!const2quantifier.contains(c)) {
+                  const2quantifier.insert(c, obj_pair_hashtable<expr, expr>());
+                }
+                if (!const2quantifier[c].contains(curr)) {
+                  const2quantifier[c].insert(curr);
+                }
+              }
+            }
+          }
+          else {
+            stack.push_back(work_item(q->get_expr(), curr.second));
+          }
+        }
+        else if (q->is_exists()) {
+          stack.push_back(work_item(q->get_expr(), curr.second));
+        }
+      }
+    }
+    // ok, now we just need to find the connected component of the last term
+    
+    obj_hashtable<expr> visited;
+    ptr_vector<expr> to_visit;
+    to_visit.push_back(g->form(g->size() - 1));
+    expr *visiting;
+    while (!to_visit.empty()) {
+      visiting = to_visit.back();
+      to_visit.pop_back();
+      visited.insert(visiting);
+      for (obj_hashtable<func_decl>::iterator constit = exp2const[visiting].begin(), constend = exp2const[visiting].end(); constit != constend; constit++) {
+        for (obj_hashtable<expr>::iterator exprit = const2exp[*constit].begin(), exprend = const2exp[*constit].end(); exprit != exprend; exprit++) {
+          if (!visited.contains(*exprit)) {
+            to_visit.push_back(*exprit);
+          }
+        }
+      }
+    }
+    for (int i = 0; i < g->size(); i++) {
+      if (visited.contains(g->form(i))) {
+        new_exprs.push_back(g->form(i));
+      }
+    }
+  }
+};
+
+tactic * mk_sine_tactic(ast_manager & m, params_ref const & p) {
+    return alloc(sine_tactic, m, p);
+}

src/tactic/sine_filter.h

@@ -0,0 +1,28 @@
+/*++
+Copyright (c) 2016 Microsoft Corporation
+
+Module Name:
+
+    sine_filter.h
+
+Abstract:
+
+    Tactic that performs Sine Qua Non premise selection
+
+Revision History:
+
+--*/
+#ifndef SINE_TACTIC_H_
+#define SINE_TACTIC_H_
+
+#include"params.h"
+class ast_manager;
+class tactic;
+
+tactic * mk_sine_tactic(ast_manager & m, params_ref const & p = params_ref());
+
+/*
+    ADD_TACTIC("sine-filter", "eliminate premises using Sine Qua Non", "mk_sine_tactic(m, p)")
+*/
+
+#endif