goto-symex: use new symbolt constructors

To the extent possible, apply resource-acquisition-is-initialisation.
The constructors ensure that at least the most essential fields (name,
type, mode) are set.

Author: tautschnig

src/goto-symex/auto_objects.cpp

@@ -22,13 +22,11 @@ exprt goto_symext::make_auto_object(const typet &type, statet &state)
   dynamic_counter++;
 
   // produce auto-object symbol
-  symbolt symbol;
+  irep_idt base_name = "auto_object" + std::to_string(dynamic_counter);
+  symbolt symbol{"symex::" + id2string(base_name), type, ID_C};
 
-  symbol.base_name="auto_object"+std::to_string(dynamic_counter);
-  symbol.name="symex::"+id2string(symbol.base_name);
+  symbol.base_name = base_name;
   symbol.is_lvalue=true;
-  symbol.type=type;
-  symbol.mode=ID_C;
 
   state.symbol_table.add(symbol);
 

src/goto-symex/symex_builtin_functions.cpp

@@ -158,14 +158,12 @@ void goto_symext::symex_allocate(
   }
 
   // value
-  symbolt value_symbol;
-
-  value_symbol.base_name="dynamic_object"+std::to_string(dynamic_counter);
-  value_symbol.name = SYMEX_DYNAMIC_PREFIX + id2string(value_symbol.base_name);
+  irep_idt base_name = "dynamic_object" + std::to_string(dynamic_counter);
+  symbolt value_symbol{
+    SYMEX_DYNAMIC_PREFIX + id2string(base_name), *object_type, mode};
+  value_symbol.base_name = base_name;
   value_symbol.is_lvalue=true;
-  value_symbol.type = *object_type;
   value_symbol.type.set(ID_C_dynamic, true);
-  value_symbol.mode = mode;
 
   state.symbol_table.add(value_symbol);