replace incomplete compound types

Author: Daniel Kroening

src/ansi-c/c_typecast.cpp

@@ -156,7 +156,6 @@ bool check_c_implicit_typecast(
           src_type_id==ID_signedbv ||
           src_type_id==ID_c_enum ||
           src_type_id==ID_c_enum_tag ||
-          src_type_id==ID_incomplete_c_enum ||
           src_type_id==ID_c_bool)
   {
     if(dest_type.id()==ID_unsignedbv ||
@@ -171,7 +170,6 @@ bool check_c_implicit_typecast(
        dest_type.id()==ID_pointer ||
        dest_type.id()==ID_c_enum ||
        dest_type.id()==ID_c_enum_tag ||
-       dest_type.id()==ID_incomplete_c_enum ||
        dest_type.id()==ID_complex)
       return false;
   }
@@ -341,9 +339,7 @@ c_typecastt::c_typet c_typecastt::get_c_type(
   {
     return PTR;
   }
-  else if(type.id()==ID_c_enum ||
-          type.id()==ID_c_enum_tag ||
-          type.id()==ID_incomplete_c_enum)
+  else if(type.id() == ID_c_enum || type.id() == ID_c_enum_tag)
   {
     return INT;
   }

src/ansi-c/c_typecheck_base.cpp

@@ -85,21 +85,15 @@ void c_typecheck_baset::typecheck_symbol(symbolt &symbol)
   }
 
   // set the pretty name
-  if(symbol.is_type &&
-     (final_type.id()==ID_struct ||
-      final_type.id()==ID_incomplete_struct))
+  if(symbol.is_type && final_type.id() == ID_struct)
   {
     symbol.pretty_name="struct "+id2string(symbol.base_name);
   }
-  else if(symbol.is_type &&
-          (final_type.id()==ID_union ||
-           final_type.id()==ID_incomplete_union))
+  else if(symbol.is_type && final_type.id() == ID_union)
   {
     symbol.pretty_name="union "+id2string(symbol.base_name);
   }
-  else if(symbol.is_type &&
-          (final_type.id()==ID_c_enum ||
-           final_type.id()==ID_incomplete_c_enum))
+  else if(symbol.is_type && final_type.id() == ID_c_enum)
   {
     symbol.pretty_name="enum "+id2string(symbol.base_name);
   }
@@ -176,12 +170,21 @@ void c_typecheck_baset::typecheck_redefinition_type(
   const typet &final_new=follow(new_symbol.type);
 
   // see if we had something incomplete before
-  if(final_old.id()==ID_incomplete_struct ||
-     final_old.id()==ID_incomplete_union ||
-     final_old.id()==ID_incomplete_c_enum)
+  if(
+    (final_old.id() == ID_struct &&
+     to_struct_type(final_old).is_incomplete()) ||
+    (final_old.id() == ID_union && to_union_type(final_old).is_incomplete()) ||
+    (final_old.id() == ID_c_enum && to_c_enum_type(final_old).is_incomplete()))
   {
-    // new one complete?
-    if("incomplete_"+final_new.id_string()==final_old.id_string())
+    // is the new one complete?
+    if(
+      final_new.id() == final_old.id() &&
+      ((final_new.id() == ID_struct &&
+        !to_struct_type(final_new).is_incomplete()) ||
+       (final_new.id() == ID_union &&
+        !to_union_type(final_new).is_incomplete()) ||
+       (final_new.id() == ID_c_enum &&
+        !to_c_enum_type(final_new).is_incomplete())))
     {
       // overwrite location
       old_symbol.location=new_symbol.location;
@@ -190,7 +193,7 @@ void c_typecheck_baset::typecheck_redefinition_type(
       old_symbol.type.swap(new_symbol.type);
     }
     else if(new_symbol.type.id()==old_symbol.type.id())
-      return;
+      return; // ignore
     else
     {
       error().source_location=new_symbol.location;
@@ -203,11 +206,15 @@ void c_typecheck_baset::typecheck_redefinition_type(
   else
   {
     // see if new one is just a tag
-    if(final_new.id()==ID_incomplete_struct ||
-       final_new.id()==ID_incomplete_union ||
-       final_new.id()==ID_incomplete_c_enum)
+    if(
+      (final_new.id() == ID_struct &&
+       to_struct_type(final_new).is_incomplete()) ||
+      (final_new.id() == ID_union &&
+       to_union_type(final_new).is_incomplete()) ||
+      (final_new.id() == ID_c_enum &&
+       to_c_enum_type(final_new).is_incomplete()))
     {
-      if("incomplete_"+final_old.id_string()==final_new.id_string())
+      if(final_old.id() == final_new.id())
       {
         // just ignore silently
       }
@@ -418,13 +425,6 @@ void c_typecheck_baset::typecheck_redefinition_non_type(
       PRECONDITION(old_symbol.type.id() != ID_symbol_type);
       old_symbol.type=new_symbol.type;
     }
-    else if((final_old.id()==ID_incomplete_c_enum ||
-             final_old.id()==ID_c_enum) &&
-            (final_new.id()==ID_incomplete_c_enum ||
-             final_new.id()==ID_c_enum))
-    {
-      // this is ok for now
-    }
     else if(final_old.id()==ID_pointer &&
             follow(final_old).subtype().id()==ID_code &&
             to_code_type(follow(final_old).subtype()).has_ellipsis() &&
@@ -477,12 +477,10 @@ void c_typecheck_baset::typecheck_redefinition_non_type(
       }
       else
       {
-        if(new_symbol.is_macro &&
-           (final_new.id()==ID_incomplete_c_enum ||
-            final_new.id()==ID_c_enum) &&
-            old_symbol.value.is_constant() &&
-            new_symbol.value.is_constant() &&
-            old_symbol.value.get(ID_value)==new_symbol.value.get(ID_value))
+        if(
+          new_symbol.is_macro && final_new.id() == ID_c_enum &&
+          old_symbol.value.is_constant() && new_symbol.value.is_constant() &&
+          old_symbol.value.get(ID_value) == new_symbol.value.get(ID_value))
         {
           // ignore
         }

src/ansi-c/c_typecheck_code.cpp

@@ -341,18 +341,20 @@ void c_typecheck_baset::typecheck_decl(codet &code)
 
 bool c_typecheck_baset::is_complete_type(const typet &type) const
 {
-  if(type.id()==ID_incomplete_struct ||
-     type.id()==ID_incomplete_union)
-    return false;
-  else if(type.id()==ID_array)
+  if(type.id() == ID_array)
   {
     if(to_array_type(type).size().is_nil())
       return false;
     return is_complete_type(type.subtype());
   }
   else if(type.id()==ID_struct || type.id()==ID_union)
   {
-    for(const auto &c : to_struct_union_type(type).components())
+    const auto &struct_union_type = to_struct_union_type(type);
+
+    if(struct_union_type.is_incomplete())
+      return false;
+
+    for(const auto &c : struct_union_type.components())
       if(!is_complete_type(c.type()))
         return false;
   }

src/ansi-c/c_typecheck_expr.cpp

@@ -1361,8 +1361,7 @@ void c_typecheck_baset::typecheck_expr_rel(
     if(follow(o_type0)==follow(o_type1))
     {
       const typet &final_type=follow(o_type0);
-      if(final_type.id()!=ID_array &&
-         final_type.id()!=ID_incomplete_struct)
+      if(final_type.id() != ID_array)
       {
         adjust_float_rel(expr);
         return; // no promotion necessary
@@ -1524,22 +1523,6 @@ void c_typecheck_baset::typecheck_expr_member(exprt &expr)
 
   type = follow(type);
 
-  if(type.id()==ID_incomplete_struct)
-  {
-    error().source_location = expr.source_location();
-    error() << "member operator got incomplete struct type "
-               "on left hand side" << eom;
-    throw 0;
-  }
-
-  if(type.id()==ID_incomplete_union)
-  {
-    error().source_location = expr.source_location();
-    error() << "member operator got incomplete union type "
-               "on left hand side" << eom;
-    throw 0;
-  }
-
   if(type.id()!=ID_struct &&
      type.id()!=ID_union)
   {
@@ -1553,6 +1536,14 @@ void c_typecheck_baset::typecheck_expr_member(exprt &expr)
   const struct_union_typet &struct_union_type=
     to_struct_union_type(type);
 
+  if(struct_union_type.is_incomplete())
+  {
+    error().source_location = expr.source_location();
+    error() << "member operator got incomplete " << type.id()
+            << " type on left hand side" << eom;
+    throw 0;
+  }
+
   const irep_idt &component_name=
     expr.get(ID_component_name);
 
@@ -1897,8 +1888,8 @@ void c_typecheck_baset::typecheck_expr_side_effect(side_effect_exprt &expr)
 
     if(final_type0.id()==ID_c_enum_tag)
     {
-      if(follow_tag(to_c_enum_tag_type(final_type0)).id()==
-         ID_incomplete_c_enum)
+      if(to_c_enum_type(follow_tag(to_c_enum_tag_type(final_type0)))
+           .is_incomplete())
       {
         error().source_location = expr.source_location();
         error() << "operator `" << statement
@@ -3166,7 +3157,17 @@ void c_typecheck_baset::typecheck_arithmetic_pointer(const exprt &expr)
 
   typet subtype=type.subtype();
 
-  if(subtype.id()==ID_incomplete_struct)
+  if(
+    subtype.id() == ID_struct_tag &&
+    to_struct_type(follow_tag(to_struct_tag_type(subtype))).is_incomplete())
+  {
+    error().source_location = expr.source_location();
+    error() << "pointer arithmetic with unknown object size" << eom;
+    throw 0;
+  }
+  else if(
+    subtype.id() == ID_union_tag &&
+    to_union_type(follow_tag(to_union_tag_type(subtype))).is_incomplete())
   {
     error().source_location = expr.source_location();
     error() << "pointer arithmetic with unknown object size" << eom;

src/ansi-c/c_typecheck_initializer.cpp

@@ -58,10 +58,12 @@ exprt c_typecheck_baset::do_initializer_rec(
 {
   const typet &full_type=follow(type);
 
-  if(full_type.id()==ID_incomplete_struct)
+  if(
+    (full_type.id() == ID_struct || full_type.id() == ID_union) &&
+    to_struct_union_type(full_type).is_incomplete())
   {
     error().source_location = value.source_location();
-    error() << "type `" << to_string(full_type)
+    error() << "type `" << to_string(type)
             << "' is still incomplete -- cannot initialize" << eom;
     throw 0;
   }

src/ansi-c/c_typecheck_type.cpp

@@ -522,9 +522,11 @@ void c_typecheck_baset::typecheck_array_type(array_typet &type)
   }
 
   // we don't allow incomplete structs or unions as subtype
+  const typet &followed_subtype = follow(type.subtype());
+
   if(
-    follow(type.subtype()).id() == ID_incomplete_struct ||
-    follow(type.subtype()).id() == ID_incomplete_union)
+    (followed_subtype.id() == ID_struct || followed_subtype.id() == ID_union) &&
+    to_struct_union_type(followed_subtype).is_incomplete())
   {
     // ISO/IEC 9899 6.7.5.2
     error().source_location = type.source_location();
@@ -805,12 +807,8 @@ void c_typecheck_baset::typecheck_compound_type(struct_union_typet &type)
 
       typet new_type=compound_symbol.type;
 
-      if(compound_symbol.type.id()==ID_struct)
-        compound_symbol.type.id(ID_incomplete_struct);
-      else if(compound_symbol.type.id()==ID_union)
-        compound_symbol.type.id(ID_incomplete_union);
-      else
-        UNREACHABLE;
+      // mark as incomplete
+      compound_symbol.type.set(ID_incomplete, true);
 
       symbolt *new_symbol;
       move_symbol(compound_symbol, new_symbol);
@@ -825,8 +823,9 @@ void c_typecheck_baset::typecheck_compound_type(struct_union_typet &type)
     else
     {
       // yes, it exists already
-      if(s_it->second.type.id()==ID_incomplete_struct ||
-         s_it->second.type.id()==ID_incomplete_union)
+      if(
+        s_it->second.type.id() == type.id() &&
+        to_struct_union_type(s_it->second.type).is_incomplete())
       {
         // Maybe we got a body now.
         if(have_body)
@@ -851,9 +850,9 @@ void c_typecheck_baset::typecheck_compound_type(struct_union_typet &type)
 
   typet tag_type;
 
-  if(type.id() == ID_union || type.id() == ID_incomplete_union)
+  if(type.id() == ID_union)
     tag_type = union_tag_typet(identifier);
-  else if(type.id() == ID_struct || type.id() == ID_incomplete_struct)
+  else if(type.id() == ID_struct)
     tag_type = struct_tag_typet(identifier);
   else
     UNREACHABLE;
@@ -1277,13 +1276,20 @@ void c_typecheck_baset::typecheck_c_enum_type(typet &type)
     // Yes.
     const symbolt &symbol=s_it->second;
 
-    if(symbol.type.id()==ID_incomplete_c_enum)
+    if(symbol.type.id() != ID_c_enum)
+    {
+      error().source_location = source_location;
+      error() << "use of tag that does not match previous declaration" << eom;
+      throw 0;
+    }
+
+    if(to_c_enum_type(symbol.type).is_incomplete())
     {
       // Ok, overwrite the type in the symbol table.
       // This gives us the members and the subtype.
       symbol_table.get_writeable_ref(symbol.name).type=enum_tag_symbol.type;
     }
-    else if(symbol.type.id()==ID_c_enum)
+    else
     {
       // We might already have the same anonymous enum, and this is
       // simply ok. Note that the C standard treats these as
@@ -1295,12 +1301,6 @@ void c_typecheck_baset::typecheck_c_enum_type(typet &type)
         throw 0;
       }
     }
-    else
-    {
-      error().source_location=source_location;
-      error() << "use of tag that does not match previous declaration" << eom;
-      throw 0;
-    }
   }
   else
   {
@@ -1340,8 +1340,7 @@ void c_typecheck_baset::typecheck_c_enum_tag_type(c_enum_tag_typet &type)
     // Yes.
     const symbolt &symbol=s_it->second;
 
-    if(symbol.type.id()!=ID_c_enum &&
-       symbol.type.id()!=ID_incomplete_c_enum)
+    if(symbol.type.id() != ID_c_enum)
     {
       error().source_location=source_location;
       error() << "use of tag that does not match previous declaration" << eom;
@@ -1351,9 +1350,9 @@ void c_typecheck_baset::typecheck_c_enum_tag_type(c_enum_tag_typet &type)
   else
   {
     // no, add it as an incomplete c_enum
-    typet new_type(ID_incomplete_c_enum);
-    new_type.subtype()=signed_int_type(); // default
+    c_enum_typet new_type(signed_int_type()); // default subtype
     new_type.add(ID_tag)=tag;
+    new_type.make_incomplete();
 
     symbolt enum_tag_symbol;
 
@@ -1423,10 +1422,10 @@ void c_typecheck_baset::typecheck_c_bit_field_type(c_bit_field_typet &type)
     // These point to an enum, which has a sub-subtype,
     // which may be smaller or larger than int, and we thus have
     // to check.
-    const typet &c_enum_type=
-      follow_tag(to_c_enum_tag_type(subtype));
+    const auto &c_enum_type =
+      to_c_enum_type(follow_tag(to_c_enum_tag_type(subtype)));
 
-    if(c_enum_type.id()==ID_incomplete_c_enum)
+    if(c_enum_type.is_incomplete())
     {
       error().source_location=type.source_location();
       error() << "bit field has incomplete enum type" << eom;