C++: use struct_tag and union_tag type

This implements a change already done in the C front-end in the C++ front end.

 - Previously, struct tags have been indicated using symbol_typet.  These
   are now indicated using struct_tag_typet.

 - Previously, union tags have been indicated using symbol_typet.  These
   are now indicated using union_tag_typet.

Author: Daniel Kroening

src/cpp/cpp_instantiate_template.cpp

@@ -187,10 +187,10 @@ const symbolt &cpp_typecheckt::class_template_symbol(
 void cpp_typecheckt::elaborate_class_template(
   const typet &type)
 {
-  if(type.id() != ID_symbol_type)
+  if(type.id() != ID_struct_tag)
     return;
 
-  const symbolt &symbol = lookup(to_symbol_type(type));
+  const symbolt &symbol = lookup(to_struct_tag_type(type));
 
   // Make a copy, as instantiate will destroy the symbol type!
   const typet t_type=symbol.type;

src/cpp/cpp_typecheck.h

@@ -222,7 +222,7 @@ class cpp_typecheckt:public c_typecheck_baset
 
   void elaborate_class_template(
     const source_locationt &source_location,
-    const symbol_typet &type);
+    const struct_tag_typet &type);
 
   unsigned template_counter;
   unsigned anon_counter;

src/cpp/cpp_typecheck_constructor.cpp

@@ -292,7 +292,7 @@ void cpp_typecheckt::default_assignop(
   std::string arg_name("ref");
 
   cpctor.add(ID_storage_spec).id(ID_cpp_storage_spec);
-  cpctor.type().id(ID_symbol_type);
+  cpctor.type().id(ID_struct_tag);
   cpctor.type().add(ID_identifier).id(symbol.name);
   cpctor.operands().push_back(exprt(ID_cpp_declarator));
   cpctor.add_source_location()=source_location;
@@ -488,7 +488,7 @@ void cpp_typecheckt::check_member_initializers(
       // Maybe it is a parent constructor?
       if(c.get_bool(ID_is_type))
       {
-        if(c.type().id() != ID_symbol_type)
+        if(c.type().id() != ID_struct_tag)
           continue;
 
         const symbolt &symb = lookup(to_symbol_type(c.type()).get_identifier());
@@ -646,7 +646,7 @@ void cpp_typecheckt::full_member_initialization(
 
         typecheck_type(member_type);
 
-        if(member_type.id() != ID_symbol_type)
+        if(member_type.id() != ID_struct_tag)
           break;
 
         if(

src/cpp/cpp_typecheck_expr.cpp

@@ -583,7 +583,7 @@ bool cpp_typecheckt::operator_is_overloaded(exprt &expr)
       // TODO: need to resolve an incomplete struct (template) here
       // go into scope of first operand
       if(
-        expr.op0().type().id() == ID_symbol_type &&
+        expr.op0().type().id() == ID_struct_tag &&
         follow(expr.op0().type()).id() == ID_struct)
       {
         const irep_idt &struct_identifier=

src/cpp/cpp_typecheck_resolve.cpp

@@ -337,9 +337,13 @@ exprt cpp_typecheck_resolvet::convert_identifier(
       {
         e.type()=c_enum_tag_typet(symbol.name);
       }
-      else // will need to do struct, union
+      else if(symbol.type.id() == ID_struct)
       {
-        e.type()=symbol_typet(symbol.name);
+        e.type() = struct_tag_typet(symbol.name);
+      }
+      else if(symbol.type.id() == ID_union)
+      {
+        e.type() = union_tag_typet(symbol.name);
       }
     }
     else if(symbol.is_macro)
@@ -908,7 +912,7 @@ cpp_scopet &cpp_typecheck_resolvet::resolve_scope(
         cpp_typecheck.cpp_scopes.current_scope().print(std::cout);
         std::cout << "X: " << id_set.size() << '\n';
 #endif
-        symbol_typet instance=
+        struct_tag_typet instance =
           disambiguate_template_classes(final_base_name, id_set, template_args);
 
         instance.add_source_location()=source_location;
@@ -954,7 +958,7 @@ cpp_scopet &cpp_typecheck_resolvet::resolve_scope(
         // the "::" triggers template elaboration
         if(!cpp_typecheck.cpp_scopes.current_scope().class_identifier.empty())
         {
-          symbol_typet instance(
+          struct_tag_typet instance(
             cpp_typecheck.cpp_scopes.current_scope().class_identifier);
           cpp_typecheck.elaborate_class_template(instance);
         }
@@ -996,7 +1000,7 @@ cpp_scopet &cpp_typecheck_resolvet::resolve_scope(
 }
 
 /// disambiguate partial specialization
-symbol_typet cpp_typecheck_resolvet::disambiguate_template_classes(
+struct_tag_typet cpp_typecheck_resolvet::disambiguate_template_classes(
   const irep_idt &base_name,
   const cpp_scopest::id_sett &id_set,
   const cpp_template_args_non_tct &full_template_args)
@@ -1192,7 +1196,7 @@ symbol_typet cpp_typecheck_resolvet::disambiguate_template_classes(
     throw 0;
   }
 
-  symbol_typet result(instance.name);
+  struct_tag_typet result(instance.name);
   result.add_source_location()=source_location;
 
   return result;
@@ -1206,7 +1210,7 @@ symbol_typet cpp_typecheck_resolvet::disambiguate_template_classes(
       match.specialization_args,
       match.full_args);
 
-  symbol_typet result(instance.name);
+  struct_tag_typet result(instance.name);
   result.add_source_location()=source_location;
 
   return result;
@@ -2072,7 +2076,7 @@ void cpp_typecheck_resolvet::apply_template_args(
         template_args_tc,
         template_args_tc);
 
-    expr=exprt(ID_type, symbol_typet(new_symbol.name));
+    expr = type_exprt(struct_tag_typet(new_symbol.name));
     expr.add_source_location()=source_location;
   }
   else
@@ -2217,11 +2221,7 @@ void cpp_typecheck_resolvet::filter_for_named_scopes(
         assert(pcomp.get_bool(ID_is_type));
         const typet &type=pcomp.type();
         assert(type.id()!=ID_struct);
-
-        if(type.id() == ID_symbol_type)
-          identifier = to_symbol_type(type).get_identifier();
-        else
-          continue;
+        continue;
       }
 
       while(true)
@@ -2240,8 +2240,6 @@ void cpp_typecheck_resolvet::filter_for_named_scopes(
           new_set.insert(&class_id);
           break;
         }
-        else if(symbol.type.id() == ID_symbol_type)
-          identifier = to_symbol_type(symbol.type).get_identifier();
         else
           break;
       }

src/cpp/cpp_typecheck_resolve.h

@@ -71,7 +71,7 @@ class cpp_typecheck_resolvet
     resolve_identifierst &identifiers,
     const wantt want);
 
-  symbol_typet disambiguate_template_classes(
+  struct_tag_typet disambiguate_template_classes(
     const irep_idt &base_name,
     const cpp_scopest::id_sett &id_set,
     const cpp_template_args_non_tct &template_args);