void ansi_c_typecheckt::typecheck()
{
  for(ansi_c_parse_treet::itemst::iterator
      it=parse_tree.items.begin();
      it!=parse_tree.items.end();
      it++)
  {
    if(it->id()==ID_declaration)
    {
      symbolt symbol;
      to_ansi_c_declaration(*it).to_symbol(symbol);
      typecheck_symbol(symbol);
    }
    else if(it->id()==ID_initializer)
    {
    }
    else
      assert(false);
  }
}
Example #2
0
void c_typecheck_baset::typecheck_code_type(code_typet &type)
{
  // the return type is still 'subtype()'
  type.return_type()=type.subtype();
  type.remove_subtype();

  code_typet::parameterst &parameters=type.parameters();

  // if we don't have any parameters, we assume it's (...)
  if(parameters.empty())
  {
    type.make_ellipsis();
  }
  else // we do have parameters
  {
    // is the last one ellipsis?
    if(type.parameters().back().id()==ID_ellipsis)
    {
      type.make_ellipsis();
      type.parameters().pop_back();
    }

    parameter_map.clear();

    for(auto &param : type.parameters())
    {
      // turn the declarations into parameters
      if(param.id()==ID_declaration)
      {
        ansi_c_declarationt &declaration=
          to_ansi_c_declaration(param);

        code_typet::parametert parameter;

        // first fix type
        typet &type=parameter.type();
        type=declaration.full_type(declaration.declarator());
        std::list<codet> tmp_clean_code;
        tmp_clean_code.swap(clean_code); // ignore side-effects
        typecheck_type(type);
        tmp_clean_code.swap(clean_code);
        adjust_function_parameter(type);

        // adjust the identifier
        irep_idt identifier=declaration.declarator().get_name();

        // abstract or not?
        if(identifier==irep_idt())
        {
          // abstract
          parameter.add_source_location()=declaration.type().source_location();
        }
        else
        {
          // make visible now, later parameters might use it
          parameter_map[identifier]=type;
          parameter.set_base_name(declaration.declarator().get_base_name());
          parameter.add_source_location()=
            declaration.declarator().source_location();
        }

        // put the parameter in place of the declaration
        param.swap(parameter);
      }
    }

    parameter_map.clear();

    if(parameters.size()==1 &&
       follow(parameters[0].type()).id()==ID_empty)
    {
      // if we just have one parameter of type void, remove it
      parameters.clear();
    }
  }

  typecheck_type(type.return_type());

  // 6.7.6.3:
  // "A function declarator shall not specify a return type that
  // is a function type or an array type."

  const typet &return_type=follow(type.return_type());

  if(return_type.id()==ID_array)
  {
    error().source_location=type.source_location();
    error() << "function must not return array" << eom;
    throw 0;
  }

  if(return_type.id()==ID_code)
  {
    error().source_location=type.source_location();
    error() << "function must not return function type" << eom;
    throw 0;
  }
}
Example #3
0
void c_typecheck_baset::typecheck_compound_body(
  struct_union_typet &type)
{
  struct_union_typet::componentst &components=type.components();

  struct_union_typet::componentst old_components;
  old_components.swap(components);

  // We get these as declarations!
  for(auto &decl : old_components)
  {
    // the arguments are member declarations or static assertions
    assert(decl.id()==ID_declaration);

    ansi_c_declarationt &declaration=
      to_ansi_c_declaration(static_cast<exprt &>(decl));

    if(declaration.get_is_static_assert())
    {
      struct_union_typet::componentt new_component;
      new_component.id(ID_static_assert);
      new_component.add_source_location()=declaration.source_location();
      new_component.operands().swap(declaration.operands());
      assert(new_component.operands().size()==2);
      components.push_back(new_component);
    }
    else
    {
      // do first half of type
      typecheck_type(declaration.type());
      make_already_typechecked(declaration.type());

      for(const auto &declarator : declaration.declarators())
      {
        struct_union_typet::componentt new_component;

        new_component.add_source_location()=
          declarator.source_location();
        new_component.set(ID_name, declarator.get_base_name());
        new_component.set(ID_pretty_name, declarator.get_base_name());
        new_component.type()=declaration.full_type(declarator);

        typecheck_type(new_component.type());

        if(!is_complete_type(new_component.type()) &&
           (new_component.type().id()!=ID_array ||
            !to_array_type(new_component.type()).is_incomplete()))
        {
          error().source_location=new_component.type().source_location();
          error() << "incomplete type not permitted here" << eom;
          throw 0;
        }

        components.push_back(new_component);
      }
    }
  }

  unsigned anon_member_counter=0;

  // scan for anonymous members, and name them
  for(auto &member : components)
  {
    if(member.get_name()!=irep_idt())
      continue;

    member.set_name("$anon"+std::to_string(anon_member_counter++));
    member.set_anonymous(true);
  }

  // scan for duplicate members

  {
    std::unordered_set<irep_idt, irep_id_hash> members;

    for(struct_union_typet::componentst::iterator
        it=components.begin();
        it!=components.end();
        it++)
    {
      if(!members.insert(it->get_name()).second)
      {
        error().source_location=it->source_location();
        error() << "duplicate member '" << it->get_name() << '\'' << eom;
        throw 0;
      }
    }
  }

  // We allow an incomplete (C99) array as _last_ member!
  // Zero-length is allowed everywhere.

  if(type.id()==ID_struct ||
     type.id()==ID_union)
  {
    for(struct_union_typet::componentst::iterator
        it=components.begin();
        it!=components.end();
        it++)
    {
      typet &c_type=it->type();

      if(c_type.id()==ID_array &&
         to_array_type(c_type).is_incomplete())
      {
        // needs to be last member
        if(type.id()==ID_struct && it!=--components.end())
        {
          error().source_location=it->source_location();
          error() << "flexible struct member must be last member" << eom;
          throw 0;
        }

        // make it zero-length
        c_type.id(ID_array);
        c_type.set(ID_size, from_integer(0, index_type()));
      }
    }
  }

  // We may add some minimal padding inside and at
  // the end of structs and
  // as additional member for unions.

  if(type.id()==ID_struct)
    add_padding(to_struct_type(type), *this);
  else if(type.id()==ID_union)
    add_padding(to_union_type(type), *this);

  // Now remove zero-width bit-fields, these are just
  // for adjusting alignment.
  for(struct_typet::componentst::iterator
      it=components.begin();
      it!=components.end();
      ) // blank
  {
    if(it->type().id()==ID_c_bit_field &&
       to_c_bit_field_type(it->type()).get_width()==0)
      it=components.erase(it);
    else
      it++;
  }

  // finally, check _Static_assert inside the compound
  for(struct_union_typet::componentst::iterator
      it=components.begin();
      it!=components.end();
      ) // no it++
  {
    if(it->id()==ID_static_assert)
    {
      assert(it->operands().size()==2);
      exprt &assertion=it->op0();
      typecheck_expr(assertion);
      typecheck_expr(it->op1());
      assertion.make_typecast(bool_typet());
      make_constant(assertion);

      if(assertion.is_false())
      {
        error().source_location=it->source_location();
        error() << "failed _Static_assert" << eom;
        throw 0;
      }
      else if(!assertion.is_true())
      {
        // should warn/complain
      }

      it=components.erase(it);
    }
    else
      it++;
  }
}
Example #4
0
void c_typecheck_baset::typecheck_c_enum_type(typet &type)
{
  // These come with the declarations
  // of the enum constants as operands.

  exprt &as_expr=static_cast<exprt &>(static_cast<irept &>(type));
  source_locationt source_location=type.source_location();

  // We allow empty enums in the grammar to get better
  // error messages.
  if(as_expr.operands().empty())
  {
    error().source_location=source_location;
    error() << "empty enum" << eom;
    throw 0;
  }

  // enums start at zero;
  // we also track min and max to find a nice base type
  mp_integer value=0, min_value=0, max_value=0;

  std::list<c_enum_typet::c_enum_membert> enum_members;

  // We need to determine a width, and a signedness
  // to obtain an 'underlying type'.
  // We just do int, but gcc might pick smaller widths
  // if the type is marked as 'packed'.
  // gcc/clang may also pick a larger width. Visual Studio doesn't.

  for(auto &op : as_expr.operands())
  {
    ansi_c_declarationt &declaration=to_ansi_c_declaration(op);
    exprt &v=declaration.declarator().value();

    if(v.is_not_nil()) // value given?
    {
      exprt tmp_v=v;
      typecheck_expr(tmp_v);
      add_rounding_mode(tmp_v);
      simplify(tmp_v, *this);
      if(tmp_v.is_true())
        value=1;
      else if(tmp_v.is_false())
        value=0;
      else if(!to_integer(tmp_v, value))
      {
      }
      else
      {
        error().source_location=v.source_location();
        error() << "enum is not a constant";
        throw 0;
      }
    }

    if(value<min_value)
      min_value=value;
    if(value>max_value)
      max_value=value;

    typet constant_type=
      enum_constant_type(min_value, max_value);

    v=from_integer(value, constant_type);

    declaration.type()=constant_type;
    typecheck_declaration(declaration);

    irep_idt base_name=
      declaration.declarator().get_base_name();

    irep_idt identifier=
      declaration.declarator().get_name();

    // store
    c_enum_typet::c_enum_membert member;
    member.set_identifier(identifier);
    member.set_base_name(base_name);
    member.set_value(integer2string(value));
    enum_members.push_back(member);

    // produce value for next constant
    ++value;
  }

  // Remove these now; we add them to the
  // c_enum symbol later.
  as_expr.operands().clear();

  bool is_packed=type.get_bool(ID_C_packed);

  // tag?
  if(type.find(ID_tag).is_nil())
  {
    // None, it's anonymous. We generate a tag.
    std::string anon_identifier="#anon_enum";

    for(const auto &member : enum_members)
    {
      anon_identifier+='$';
      anon_identifier+=id2string(member.get_base_name());
      anon_identifier+='=';
      anon_identifier+=id2string(member.get_value());
    }

    if(is_packed)
      anon_identifier+="#packed";

    type.add(ID_tag).set(ID_identifier, anon_identifier);
  }

  irept &tag=type.add(ID_tag);
  irep_idt base_name=tag.get(ID_C_base_name);
  irep_idt identifier=tag.get(ID_identifier);

  // Put into symbol table
  symbolt enum_tag_symbol;

  enum_tag_symbol.is_type=true;
  enum_tag_symbol.type=type;
  enum_tag_symbol.location=source_location;
  enum_tag_symbol.is_file_local=true;
  enum_tag_symbol.base_name=base_name;
  enum_tag_symbol.name=identifier;

  // throw in the enum members as 'body'
  irept::subt &body=enum_tag_symbol.type.add(ID_body).get_sub();

  for(const auto &member : enum_members)
    body.push_back(member);

  // We use a subtype to store the underlying type.
  typet underlying_type=
    enum_underlying_type(min_value, max_value, is_packed);

  enum_tag_symbol.type.subtype()=underlying_type;

  // is it in the symbol table already?
  symbol_tablet::symbolst::iterator s_it=
    symbol_table.symbols.find(identifier);

  if(s_it!=symbol_table.symbols.end())
  {
    // Yes.
    symbolt &symbol=s_it->second;

    if(symbol.type.id()==ID_incomplete_c_enum)
    {
      // Ok, overwrite the type in the symbol table.
      // This gives us the members and the subtype.
      symbol.type=enum_tag_symbol.type;
    }
    else if(symbol.type.id()==ID_c_enum)
    {
      // We might already have the same anonymous enum, and this is
      // simply ok. Note that the C standard treats these as
      // different types.
      if(!base_name.empty())
      {
        error().source_location=type.source_location();
        error() << "redeclaration of enum tag" << eom;
        throw 0;
      }
    }
    else
    {
      error().source_location=source_location;
      error() << "use of tag that does not match previous declaration" << eom;
      throw 0;
    }
  }
  else
  {
    symbolt *new_symbol;
    move_symbol(enum_tag_symbol, new_symbol);
  }

  // We produce a c_enum_tag as the resulting type.
  type.id(ID_c_enum_tag);
  type.remove(ID_tag);
  type.set(ID_identifier, identifier);
}