Use sharing_mapt for abstract environment

Author: martin

src/util/sharing_map.h

@@ -414,6 +414,12 @@ class sharing_mapt
   ///
   /// \param [out] view: Empty view
   void get_view(viewt &view) const;
+  viewt get_view() const
+  {
+    viewt result;
+    get_view(result);
+    return result;
+  }
 
   /// Get a delta view of the elements in the map
   ///

src/util/std_expr.h

@@ -114,6 +114,16 @@ class symbol_exprt : public nullary_exprt
   }
 };
 
+namespace std {
+  template<> struct hash<::symbol_exprt>
+  {
+    size_t operator()(const ::symbol_exprt& sym)
+    {
+      return irep_id_hash()(sym.get_identifier());
+    }
+  };
+}
+
 /// Expression to hold a symbol (variable) with extra accessors to
 /// ID_c_static_lifetime and ID_C_thread_local
 class decorated_symbol_exprt:public symbol_exprt