Z3 sources

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

lib/shared_occs.cpp

@@ -0,0 +1,140 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    shared_occs.cpp
+
+Abstract:
+
+    Functor for computing the shared subterms in a given
+    term.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-04-01.
+
+Revision History:
+--*/
+#include"shared_occs.h"
+#include"ast_smt2_pp.h"
+#include"ref_util.h"
+
+inline void shared_occs::insert(expr * t) {
+    obj_hashtable<expr>::entry * dummy;
+    if (m_shared.insert_if_not_there_core(t, dummy))
+        m.inc_ref(t);
+}
+
+void shared_occs::reset() { 
+    dec_ref_collection_values(m, m_shared);
+    m_shared.reset(); 
+}
+
+void shared_occs::cleanup() { 
+    reset();
+    m_shared.finalize();
+    m_stack.finalize(); 
+}
+
+shared_occs::~shared_occs() {
+    reset();
+}
+
+inline bool shared_occs::process(expr * t, shared_occs_mark & visited) {
+    switch (t->get_kind()) {
+    case AST_APP: {
+        unsigned num_args = to_app(t)->get_num_args();
+        if (t->get_ref_count() > 1 && (m_track_atomic || num_args > 0)) {
+            if (visited.is_marked(t)) {
+                insert(t);
+                return true;
+            }
+            visited.mark(t);
+        }
+        if (num_args == 0)
+            return true; // done with t
+        m_stack.push_back(frame(t, 0)); // need to create frame if num_args > 0
+        return false; 
+    }
+    case AST_VAR:
+        if (m_track_atomic && t->get_ref_count() > 1) {
+            if (visited.is_marked(t))
+                insert(t);
+            else
+                visited.mark(t);
+        }
+        return true; // done with t
+    case AST_QUANTIFIER:
+        if (t->get_ref_count() > 1) {
+            if (visited.is_marked(t)) {
+                insert(t);
+                return true; // done with t
+            }
+            visited.mark(t);
+        }
+        if (!m_visit_quantifiers)
+            return true; 
+        m_stack.push_back(frame(t, 0));
+        return false; 
+    default:
+        UNREACHABLE();
+        return true;
+    }
+}
+
+void shared_occs::operator()(expr * t, shared_occs_mark & visited) {
+    SASSERT(m_stack.empty());
+    if (process(t, visited)) {
+        return;
+    }
+    SASSERT(!m_stack.empty());
+    while (!m_stack.empty()) {
+    start:
+        frame & fr  = m_stack.back();
+        expr * curr = fr.first;
+        switch (curr->get_kind()) {
+        case AST_APP: {
+            unsigned num_args = to_app(curr)->get_num_args();
+            while (fr.second < num_args) {
+                expr * arg = to_app(curr)->get_arg(fr.second);
+                fr.second++;
+                if (!process(arg, visited))
+                    goto start;
+            }
+            break;
+        }
+        case AST_QUANTIFIER: {
+            SASSERT(m_visit_quantifiers);
+            unsigned num_children = m_visit_patterns ? to_quantifier(curr)->get_num_children() : 1;
+            while (fr.second < num_children) {
+                expr * child = to_quantifier(curr)->get_child(fr.second);
+                fr.second++;
+                if (!process(child, visited))
+                    goto start;
+            }
+            break;
+        }
+        default:
+            UNREACHABLE();
+            break;
+        }
+        m_stack.pop_back();
+    }
+}
+
+
+void shared_occs::operator()(expr * t) {
+    SASSERT(m_stack.empty());
+    shared_occs_mark visited;
+    reset();
+    operator()(t, visited);
+}
+
+void shared_occs::display(std::ostream & out, ast_manager & m) const {
+    iterator it =  begin_shared();
+    iterator end = end_shared();
+    for (; it != end; ++it) {
+        out << mk_ismt2_pp(*it, m) << "\n";
+    }
+}