Merge pull request diffblue#85 from diffblue/mariusmc92/feature/recency_analysis

Added first phase of Recency Analysis behaviour

Author: NathanJPhillips

src/pointer-analysis/local_value_set.cpp

@@ -14,6 +14,8 @@ Author: Chris Smowton, [email protected]
 
 #include <pointer-analysis/dynamic_object_name.h>
 
+#include <boost/range/algorithm.hpp>
+
 void local_value_sett::make_union_adjusting_evs_types(
   object_mapt &dest,
   const object_mapt &src,
@@ -226,6 +228,104 @@ void local_value_sett::get_value_set_rec(
   baset::get_value_set_rec(expr, dest, suffix, original_type, ns);
 }
 
+/*******************************************************************\
+
+Function: local_value_sett::apply_side_effects
+
+  Inputs: rhs:        Right-hand-side of an assignment code
+                      expression.
+          ns:         Namespace.
+
+ Outputs:
+
+ Purpose: Applying side effects needed in Recency Analysis.
+
+\*******************************************************************/
+
+void local_value_sett::apply_side_effects(
+  const exprt &rhs,
+  const namespacet &ns)
+{
+  if(rhs.id()==ID_side_effect &&
+    rhs.get(ID_statement)==ID_malloc)
+  {
+    const typet &dynamic_type=
+      static_cast<const typet &>(rhs.find("#type"));
+
+    // Replace all the current most-recent-allocation dynamic-objects
+    // with the corresponding any-allocation ones
+    for(auto &value : values)
+    {
+      entryt &entry=value.second;
+      object_map_dt &object_map=entry.object_map.write();
+
+      // Look-up for the first appearance of the current
+      // most-recent dynamic-object in the current object-map
+      object_map_dt::iterator it=boost::range::find_if(
+        object_map,
+        [this] (object_map_dt::reference object)
+        {
+          exprt &o=object_numbering[object.first];
+          if(o.id()!=ID_dynamic_object)
+            return false;
+
+          dynamic_object_exprt &dynamic_object=to_dynamic_object_expr(o);
+
+          return dynamic_object.get_instance()==location_number &&
+            dynamic_object.get_recency()==
+              dynamic_object_exprt::recencyt::MOST_RECENT_ALLOCATION;
+        });
+
+      if(it==object_map.end())
+        continue;
+
+      // Delete the most-recent dynamic-object from the current object_map
+      object_map.erase(it);
+
+      int index_dynamic_object_recent=it->first;
+
+      // Create the any-allocation dynamic-object
+      // by copying the existing most-recent one and adjusting the recency flag
+      dynamic_object_exprt dynamic_object_any_allocation=
+        to_dynamic_object_expr(object_numbering[index_dynamic_object_recent]);
+      dynamic_object_any_allocation.set_recency(false);
+
+      // Add the newly created any-allocation dynamic-object
+      // in the current rhs' object_map
+      insert(entry.object_map, dynamic_object_any_allocation, 0);
+    }
+
+    const std::string name_most_recent=
+      prefix_dynamic_object+
+      std::to_string(location_number)+
+      id2string(ID_most_recent_allocation);
+    const std::string name_any_allocation=
+      prefix_dynamic_object+
+      std::to_string(location_number)+
+      id2string(ID_any_allocation);
+
+    // Iterates over the domain's entries and when we find the current
+    // most-recent-allocation dynamic-object, add its object-map
+    // to its correspondent any-allocation dynamic-object's object-map
+    for(auto &value : values)
+    {
+      entryt &entry=value.second;
+
+      if(entry.identifier==name_most_recent)
+      {
+        entryt &entry_any_allocation=get_entry(
+          entryt(name_any_allocation, entry.suffix),
+          dynamic_type,
+          ns);
+
+        // Add into the any-allocation dynamic-object's object_map
+        // the most-recent-allocation dynamic-object's object_map
+        make_union(entry_any_allocation.object_map, entry.object_map);
+      }
+    }
+  }
+}
+
 void local_value_sett::assign(
   const exprt &lhs,
   const exprt &rhs,
@@ -288,6 +388,7 @@ void local_value_sett::assign(
       }
     }
 #endif
+    apply_side_effects(rhs, ns);
 
     assign_rec(lhs, values_rhs, "", ns, add_to_sets);
   }
@@ -334,9 +435,7 @@ void local_value_sett::assign_rec(
     const dynamic_object_exprt &dynamic_object=
       to_dynamic_object_expr(lhs);
 
-    const std::string name=
-      prefix_dynamic_object+
-      std::to_string(dynamic_object.get_instance());
+    std::string name=get_dynamic_object_name(dynamic_object);
 
     typet declared_on_type;
     std::string suffix_without_subtype_ignored;
@@ -346,12 +445,27 @@ void local_value_sett::assign_rec(
       ns,
       declared_on_type,
       suffix_without_subtype_ignored);
-    entryt &e=get_entry(
+
+    entryt &entry=get_entry(
       entryt(name, suffix, declared_on_type),
       lhs.type(),
       ns);
 
-    make_union(e.object_map, values_rhs);
+    if(dynamic_object.get_recency()==
+      dynamic_object_exprt::recencyt::MOST_RECENT_ALLOCATION &&
+      !add_to_sets)
+    {
+      // We have to assign the values from the current rhs to the
+      // current most-recent dynamic-object's object-map
+
+      // Strong-update of the dynamic-object
+      entry.object_map=values_rhs;
+    }
+    else
+    {
+      // Weak-update of the dynamic-object
+      make_union(entry.object_map, values_rhs);
+    }
     return;
   }
   else if(lhs.id()==ID_external_value_set)

src/pointer-analysis/local_value_set.h

@@ -63,6 +63,10 @@ class local_value_sett:public value_sett
   void apply_code(
     const codet &,
     const namespacet &) override;
+
+  void apply_side_effects(
+    const exprt &rhs,
+    const namespacet &ns);
 };
 
 #endif