Пример #1
0
void java_bytecode_convert_classt::convert(
  symbolt &class_symbol,
  const fieldt &f)
{
  typet field_type=java_type_from_string(f.signature);

  // is this a static field?
  if(f.is_static)
  {
    // Create the symbol; we won't add to the struct type.
    symbolt new_symbol;

    new_symbol.is_static_lifetime=true;
    new_symbol.is_lvalue=true;
    new_symbol.is_state_var=true;
    new_symbol.name=id2string(class_symbol.name)+"."+id2string(f.name);
    new_symbol.base_name=f.name;
    new_symbol.type=field_type;
    new_symbol.pretty_name=id2string(class_symbol.pretty_name)+
      "."+id2string(f.name);
    new_symbol.mode=ID_java;
    new_symbol.is_type=false;
    const namespacet ns(symbol_table);
    new_symbol.value=
      zero_initializer(
        field_type,
        class_symbol.location,
        ns,
        get_message_handler());

    // Do we have the static field symbol already?
    const auto s_it=symbol_table.symbols.find(new_symbol.name);
    if(s_it!=symbol_table.symbols.end())
      symbol_table.symbols.erase(s_it); // erase, we stubbed it

    if(symbol_table.add(new_symbol))
      assert(false && "failed to add static field symbol");
  }
  else
  {
    class_typet &class_type=to_class_type(class_symbol.type);

    class_type.components().push_back(class_typet::componentt());
    class_typet::componentt &component=class_type.components().back();

    component.set_name(f.name);
    component.set_base_name(f.name);
    component.set_pretty_name(f.name);
    component.type()=field_type;

    if(f.is_private)
      component.set_access(ID_private);
    else if(f.is_protected)
      component.set_access(ID_protected);
    else if(f.is_public)
      component.set_access(ID_public);
  }
}
Пример #2
0
void c_typecheck_baset::do_initializer(symbolt &symbol)
{
  // this one doesn't need initialization
  if(has_prefix(id2string(symbol.name), CPROVER_PREFIX "constant_infinity"))
    return;

  if(symbol.static_lifetime)
  {
    if(symbol.value.is_nil())
    {
      const typet &final_type=follow(symbol.type);
      
      if(final_type.id()!=ID_incomplete_struct &&
         final_type.id()!=ID_incomplete_array &&
         final_type.id()!=ID_empty)
      {
        // zero initializer
        symbol.value=zero_initializer(symbol.type, symbol.location);
        symbol.value.set("#zero_initializer", true);
      }
    }
    else
    {
      typecheck_expr(symbol.value);
      do_initializer(symbol.value, symbol.type, true);
      
      if(follow(symbol.type).id()==ID_incomplete_array)
        symbol.type=symbol.value.type();
    }
  }
  else if(!symbol.is_type)
  {
    const typet &final_type=follow(symbol.type);
    
    if(final_type.id()==ID_incomplete_c_enum ||
       final_type.id()==ID_c_enum)
    {
      if(symbol.is_macro)
      {
        // these must have a constant value
        assert(symbol.value.is_not_nil());
        typecheck_expr(symbol.value);
        locationt location=symbol.value.location();
        do_initializer(symbol.value, symbol.type, true);
        make_constant(symbol.value);
      }
    }
    else if(symbol.value.is_not_nil())
    {
      typecheck_expr(symbol.value);
      do_initializer(symbol.value, symbol.type, true);
      
      if(follow(symbol.type).id()==ID_incomplete_array)
        symbol.type=symbol.value.type();
    }
  }
}
Пример #3
0
exprt c_typecheck_baset::do_initializer_list(
  const exprt &value,
  const typet &type,
  bool force_constant)
{
  assert(value.id()==ID_initializer_list);

  if(type.id()==ID_symbol)
    return do_initializer_list(
      value, follow(type), force_constant);

  exprt result;
  if(type.id()==ID_struct ||
     type.id()==ID_array ||
     type.id()==ID_union)
  {
    // start with zero everywhere
    result=zero_initializer(type, value.location());
  }
  else if(type.id()==ID_incomplete_array)
  {
    // start with empty array
    result=exprt(ID_array, type);
    result.location()=value.location();
  }
  else
  {
    // The initializer for a scalar shall be a single expression,
    // * optionally enclosed in braces. *

    if(value.operands().size()==1)
      return do_initializer_rec(value.op0(), type, force_constant);
    
    err_location(value);
    str << "cannot initialize `" << to_string(type) << "' with "
           "an initializer list";
    throw 0;
  }

  designatort current_designator;
  
  designator_enter(type, current_designator);
    
  forall_operands(it, value)
  {
    do_designated_initializer(
      result, current_designator, *it, force_constant);

    // increase designator -- might go up    
    increment_designator(current_designator);
  }
Пример #4
0
void c_typecheck_baset::typecheck_return(codet &code)
{
  if(code.operands().empty())
  {
    if(follow(return_type).id()!=ID_empty)
    {
      // gcc doesn't actually complain, it just warns!
      // We'll put a zero here, which is dubious.
      exprt zero=zero_initializer(return_type, code.source_location(), *this, get_message_handler());
      code.copy_to_operands(zero);
    }
  }
  else if(code.operands().size()==1)
  {
    typecheck_expr(code.op0());

    if(follow(return_type).id()==ID_empty)
    {
      // gcc doesn't actually complain, it just warns!
      if(follow(code.op0().type()).id()!=ID_empty)
      {
        warning().source_location=code.source_location();

        warning() << "function has return void ";
        warning() << "but a return statement returning ";
        warning() << to_string(follow(code.op0().type()));
        warning() << eom;

        code.op0().make_typecast(return_type);
      }
    }
    else
      implicit_typecast(code.op0(), return_type);
  }
  else
  {
    err_location(code);
    error() << "return expected to have 0 or 1 operands" << eom;
    throw 0;
  }
}
Пример #5
0
void goto_convertt::do_java_new(
  const exprt &lhs,
  const side_effect_exprt &rhs,
  goto_programt &dest)
{
  if(lhs.is_nil())
    throw "do_java_new without lhs is yet to be implemented";
    
  source_locationt location=rhs.source_location();

  assert(rhs.operands().empty());

  if(rhs.type().id()!=ID_pointer)
    throw "do_java_new returns pointer";

  typet object_type=rhs.type().subtype();
  
  // build size expression
  exprt object_size=size_of_expr(object_type, ns);
  
  if(object_size.is_nil())
    throw "do_java_new got nil object_size";

  // we produce a malloc side-effect, which stays
  side_effect_exprt malloc_expr(ID_malloc);
  malloc_expr.copy_to_operands(object_size);
  malloc_expr.type()=pointer_typet(object_type);

  goto_programt::targett t_n=dest.add_instruction(ASSIGN);
  t_n->code=code_assignt(lhs, malloc_expr);
  t_n->source_location=location;
  
  // zero-initialize the object
  dereference_exprt deref(lhs, object_type);
  exprt zero_object=zero_initializer(object_type, location, ns, get_message_handler());
  set_class_identifier(to_struct_expr(zero_object), ns, to_symbol_type(object_type));
  goto_programt::targett t_i=dest.add_instruction(ASSIGN);
  t_i->code=code_assignt(deref, zero_object);
  t_i->source_location=location;
}
Пример #6
0
void cpp_typecheckt::static_initialization()
{
  code_blockt block_sini; // Static Initialization Block
  code_blockt block_dini; // Dynamic Initialization Block

  disable_access_control = true;

  // first do zero initialization
  context.foreach_operand([this, &block_sini](const symbolt &s) {
    if(!s.static_lifetime || s.mode != current_mode)
      return;

    // it has a non-code initializer already?
    if(s.value.is_not_nil() && s.value.id() != "code")
      return;

    // it's a declaration only
    if(s.is_extern)
      return;

    if(!s.lvalue)
      return;

    zero_initializer(
      cpp_symbol_expr(s), s.type, s.location, block_sini.operands());
  });

  while(!dinis.empty())
  {
    symbolt &symbol = *context.find_symbol(dinis.front());
    dinis.pop_front();

    if(symbol.is_extern)
      continue;

    if(symbol.mode != current_mode)
      continue;

    assert(symbol.static_lifetime);
    assert(!symbol.is_type);
    assert(symbol.type.id() != "code");

    exprt symexpr = cpp_symbol_expr(symbol);

    if(symbol.value.is_not_nil())
    {
      if(!cpp_is_pod(symbol.type))
      {
        block_dini.move_to_operands(symbol.value);
      }
      else
      {
        exprt symbexpr("symbol", symbol.type);
        symbexpr.identifier(symbol.name);

        codet code;
        code.set_statement("assign");
        code.copy_to_operands(symbexpr, symbol.value);
        code.location() = symbol.location;

        if(symbol.value.id() == "constant")
          block_sini.move_to_operands(code);
        else
          block_dini.move_to_operands(code);
      }

      // Make it nil because we do not want
      // global_init to try to initialize the
      // object
      symbol.value.make_nil();
    }
    else
    {
      exprt::operandst ops;

      codet call = cpp_constructor(locationt(), symexpr, ops);

      if(call.is_not_nil())
        block_dini.move_to_operands(call);
    }
  }

  block_sini.move_to_operands(block_dini);

  // Create the initialization procedure
  symbolt init_symbol;

  init_symbol.name = "#ini#" + id2string(module);
  init_symbol.base_name = "#ini#" + id2string(module);
  init_symbol.value.swap(block_sini);
  init_symbol.mode = current_mode;
  init_symbol.module = module;
  init_symbol.type = code_typet();
  init_symbol.type.add("return_type") = typet("empty");
  init_symbol.type.set("initialization", true);
  init_symbol.is_type = false;
  init_symbol.is_macro = false;

  context.move(init_symbol);

  disable_access_control = false;
}
Пример #7
0
bool static_lifetime_init(
  symbol_tablet &symbol_table,
  const source_locationt &source_location,
  message_handlert &message_handler)
{
  namespacet ns(symbol_table);

  symbol_tablet::symbolst::iterator s_it=
    symbol_table.symbols.find(INITIALIZE_FUNCTION);

  if(s_it==symbol_table.symbols.end())
    return false;

  symbolt &init_symbol=s_it->second;

  init_symbol.value=code_blockt();
  init_symbol.value.add_source_location()=source_location;

  code_blockt &dest=to_code_block(to_code(init_symbol.value));

  // add the magic label to hide
  dest.add(code_labelt("__CPROVER_HIDE", code_skipt()));

  // do assignments based on "value"

  // sort alphabetically for reproducible results
  std::set<std::string> symbols;

  forall_symbols(it, symbol_table.symbols)
    symbols.insert(id2string(it->first));

  for(const std::string &id : symbols)
  {
    const symbolt &symbol=ns.lookup(id);

    const irep_idt &identifier=symbol.name;

    if(!symbol.is_static_lifetime)
      continue;

    if(symbol.is_type || symbol.is_macro)
      continue;

    // special values
    if(identifier==CPROVER_PREFIX "constant_infinity_uint" ||
       identifier==CPROVER_PREFIX "memory" ||
       identifier=="__func__" ||
       identifier=="__FUNCTION__" ||
       identifier=="__PRETTY_FUNCTION__" ||
       identifier=="argc'" ||
       identifier=="argv'" ||
       identifier=="envp'" ||
       identifier=="envp_size'")
      continue;

    // just for linking
    if(has_prefix(id, CPROVER_PREFIX "architecture_"))
      continue;

    const typet &type=ns.follow(symbol.type);

    // check type
    if(type.id()==ID_code ||
       type.id()==ID_empty)
      continue;

    // We won't try to initialize any symbols that have
    // remained incomplete.

    if(symbol.value.is_nil() &&
       symbol.is_extern)
      // Compilers would usually complain about these
      // symbols being undefined.
      continue;

    if(type.id()==ID_array &&
       to_array_type(type).size().is_nil())
    {
      // C standard 6.9.2, paragraph 5
      // adjust the type to an array of size 1
      symbol_tablet::symbolst::iterator it=
        symbol_table.symbols.find(identifier);
      assert(it!=symbol_table.symbols.end());

      it->second.type=type;
      it->second.type.set(ID_size, from_integer(1, size_type()));
    }

    if(type.id()==ID_incomplete_struct ||
       type.id()==ID_incomplete_union)
      continue; // do not initialize

    if(symbol.value.id()==ID_nondet)
      continue; // do not initialize

    exprt rhs;

    if(symbol.value.is_nil())
    {
      try
      {
        namespacet ns(symbol_table);
        rhs=zero_initializer(symbol.type, symbol.location, ns, message_handler);
        assert(rhs.is_not_nil());
      }
      catch(...)
      {
        return true;
      }
    }
    else
      rhs=symbol.value;

    code_assignt code(symbol.symbol_expr(), rhs);
    code.add_source_location()=symbol.location;

    dest.move_to_operands(code);
  }

  // call designated "initialization" functions

  for(const std::string &id : symbols)
  {
    const symbolt &symbol=ns.lookup(id);

    if(symbol.type.id()==ID_code &&
       to_code_type(symbol.type).return_type().id()==ID_constructor)
    {
      code_function_callt function_call;
      function_call.function()=symbol.symbol_expr();
      function_call.add_source_location()=source_location;
      dest.move_to_operands(function_call);
    }
  }

  return false;
}
Пример #8
0
exprt c_typecheck_baset::do_initializer_list(
  const exprt &value,
  const typet &type,
  bool force_constant)
{
  assert(value.id()==ID_initializer_list);

  const typet &full_type=follow(type);

  exprt result;
  if(full_type.id()==ID_struct ||
     full_type.id()==ID_union ||
     full_type.id()==ID_vector)
  {
    // start with zero everywhere
    result=
      zero_initializer(
        type, value.source_location(), *this, get_message_handler());
  }
  else if(full_type.id()==ID_array)
  {
    if(to_array_type(full_type).size().is_nil())
    {
      // start with empty array
      result=exprt(ID_array, full_type);
      result.add_source_location()=value.source_location();
    }
    else
    {
      // start with zero everywhere
      result=
        zero_initializer(
          type, value.source_location(), *this, get_message_handler());
    }

    // 6.7.9, 14: An array of character type may be initialized by a character
    // string literal or UTF-8 string literal, optionally enclosed in braces.
    if(value.operands().size()>=1 &&
       value.op0().id()==ID_string_constant &&
       (full_type.subtype().id()==ID_signedbv ||
        full_type.subtype().id()==ID_unsignedbv) &&
       full_type.subtype().get(ID_width)==char_type().get(ID_width))
    {
      if(value.operands().size()>1)
      {
        warning().source_location=value.find_source_location();
        warning() << "ignoring excess initializers" << eom;
      }

      return do_initializer_rec(value.op0(), type, force_constant);
    }
  }
  else
  {
    // The initializer for a scalar shall be a single expression,
    // * optionally enclosed in braces. *

    if(value.operands().size()==1)
      return do_initializer_rec(value.op0(), type, force_constant);

    err_location(value);
    error() << "cannot initialize `" << to_string(full_type)
            << "' with an initializer list" << eom;
    throw 0;
  }

  designatort current_designator;

  designator_enter(type, current_designator);

  forall_operands(it, value)
  {
    do_designated_initializer(
      result, current_designator, *it, force_constant);

    // increase designator -- might go up
    increment_designator(current_designator);
  }
Пример #9
0
exprt c_typecheck_baset::do_initializer_rec(
  const exprt &value,
  const typet &type,
  bool force_constant)
{
  const typet &full_type=follow(type);

  if(full_type.id()==ID_incomplete_struct)
  {
    err_location(value);
    error() << "type `" << to_string(full_type)
            << "' is still incomplete -- cannot initialize" << eom;
    throw 0;
  }

  if(value.id()==ID_initializer_list)
    return do_initializer_list(value, type, force_constant);

  if(value.id()==ID_array &&
     value.get_bool(ID_C_string_constant) &&
     full_type.id()==ID_array &&
     (full_type.subtype().id()==ID_signedbv ||
      full_type.subtype().id()==ID_unsignedbv) &&
      full_type.subtype().get(ID_width)==value.type().subtype().get(ID_width))
  {
    exprt tmp=value;

    // adjust char type
    tmp.type().subtype()=full_type.subtype();

    Forall_operands(it, tmp)
      it->type()=full_type.subtype();

    if(full_type.id()==ID_array &&
       to_array_type(full_type).is_complete())
    {
      // check size
      mp_integer array_size;
      if(to_integer(to_array_type(full_type).size(), array_size))
      {
        err_location(value);
        error() << "array size needs to be constant, got "
                << to_string(to_array_type(full_type).size()) << eom;
        throw 0;
      }

      if(array_size<0)
      {
        err_location(value);
        error() << "array size must not be negative" << eom;
        throw 0;
      }

      if(mp_integer(tmp.operands().size())>array_size)
      {
        // cut off long strings. gcc does a warning for this
        tmp.operands().resize(integer2size_t(array_size));
        tmp.type()=type;
      }
      else if(mp_integer(tmp.operands().size())<array_size)
      {
        // fill up
        tmp.type()=type;
        exprt zero=
          zero_initializer(
            full_type.subtype(),
            value.source_location(),
            *this,
            get_message_handler());
        tmp.operands().resize(integer2size_t(array_size), zero);
      }
    }

    return tmp;
  }

  if(value.id()==ID_string_constant &&
     full_type.id()==ID_array &&
     (full_type.subtype().id()==ID_signedbv ||
      full_type.subtype().id()==ID_unsignedbv) &&
      full_type.subtype().get(ID_width)==char_type().get(ID_width))
  {
    // will go away, to be replaced by the above block

    string_constantt tmp1=to_string_constant(value);
    // adjust char type
    tmp1.type().subtype()=full_type.subtype();

    exprt tmp2=tmp1.to_array_expr();

    if(full_type.id()==ID_array &&
       to_array_type(full_type).is_complete())
    {
      // check size
      mp_integer array_size;
      if(to_integer(to_array_type(full_type).size(), array_size))
      {
        err_location(value);
        error() << "array size needs to be constant, got "
                << to_string(to_array_type(full_type).size()) << eom;
        throw 0;
      }

      if(array_size<0)
      {
        err_location(value);
        error() << "array size must not be negative" << eom;
        throw 0;
      }

      if(mp_integer(tmp2.operands().size())>array_size)
      {
        // cut off long strings. gcc does a warning for this
        tmp2.operands().resize(integer2size_t(array_size));
        tmp2.type()=type;
      }
      else if(mp_integer(tmp2.operands().size())<array_size)
      {
        // fill up
        tmp2.type()=type;
        exprt zero=
          zero_initializer(
            full_type.subtype(),
            value.source_location(),
            *this,
            get_message_handler());
        tmp2.operands().resize(integer2size_t(array_size), zero);
      }
    }

    return tmp2;
  }

  if(full_type.id()==ID_array &&
     to_array_type(full_type).size().is_nil())
  {
    err_location(value);
    error() << "type `" << to_string(full_type)
            << "' cannot be initialized with `" << to_string(value)
            << "'" << eom;
    throw 0;
  }

  if(value.id()==ID_designated_initializer)
  {
    err_location(value);
    error() << "type `" << to_string(full_type)
            << "' cannot be initialized with designated initializer"
            << eom;
    throw 0;
  }

  exprt result=value;
  implicit_typecast(result, type);
  return result;
}
Пример #10
0
void c_typecheck_baset::do_designated_initializer(
  exprt &result,
  designatort &designator,
  const exprt &value,
  bool force_constant)
{
  assert(!designator.empty());

  if(value.id()==ID_designated_initializer)
  {
    assert(value.operands().size()==1);

    designator=
      make_designator(
        designator.front().type,
        static_cast<const exprt &>(value.find(ID_designator)));

    assert(!designator.empty());

    return do_designated_initializer(
      result, designator, value.op0(), force_constant);
  }

  exprt *dest=&result;

  // first phase: follow given designator

  for(size_t i=0; i<designator.size(); i++)
  {
    size_t index=designator[i].index;
    const typet &type=designator[i].type;
    const typet &full_type=follow(type);

    if(full_type.id()==ID_array ||
       full_type.id()==ID_vector)
    {
      if(index>=dest->operands().size())
      {
        if(full_type.id()==ID_array &&
           (to_array_type(full_type).size().is_zero() ||
            to_array_type(full_type).size().is_nil()))
        {
          // we are willing to grow an incomplete or zero-sized array
          exprt zero=
            zero_initializer(
              full_type.subtype(),
              value.source_location(),
              *this,
              get_message_handler());
          dest->operands().resize(integer2size_t(index)+1, zero);

          // todo: adjust type!
        }
        else
        {
          err_location(value);
          error() << "array index designator " << index
                  << " out of bounds (" << dest->operands().size()
                  << ")" << eom;
          throw 0;
        }
      }

      dest=&(dest->operands()[integer2size_t(index)]);
    }
    else if(full_type.id()==ID_struct)
    {
      const struct_typet::componentst &components=
        to_struct_type(full_type).components();

      if(index>=dest->operands().size())
      {
        err_location(value);
        error() << "structure member designator " << index
                << " out of bounds (" << dest->operands().size()
                << ")" << eom;
        throw 0;
      }

      assert(index<components.size());
      assert(components[index].type().id()!=ID_code &&
             !components[index].get_is_padding());

      dest=&(dest->operands()[index]);
    }
    else if(full_type.id()==ID_union)
    {
      const union_typet &union_type=to_union_type(full_type);

      const union_typet::componentst &components=
        union_type.components();

      assert(index<components.size());

      const union_typet::componentt &component=union_type.components()[index];

      if(dest->id()==ID_union &&
         dest->get(ID_component_name)==component.get_name())
      {
        // Already right union component. We can initialize multiple submembers,
        // so do not overwrite this.
      }
      else
      {
        // Note that gcc issues a warning if the union component is switched.
        // Build a union expression from given component.
        union_exprt union_expr(type);
        union_expr.op()=
          zero_initializer(
            component.type(),
            value.source_location(),
            *this,
            get_message_handler());
        union_expr.add_source_location()=value.source_location();
        union_expr.set_component_name(component.get_name());
        *dest=union_expr;
      }

      dest=&(dest->op0());
    }
    else
      assert(false);
  }

  // second phase: assign value
  // for this, we may need to go down, adding to the designator

  while(true)
  {
    // see what type we have to initialize

    const typet &type=designator.back().subtype;
    const typet &full_type=follow(type);
    assert(full_type.id()!=ID_symbol);

    // do we initialize a scalar?
    if(full_type.id()!=ID_struct &&
       full_type.id()!=ID_union &&
       full_type.id()!=ID_array &&
       full_type.id()!=ID_vector)
    {
      // The initializer for a scalar shall be a single expression,
      // * optionally enclosed in braces. *

      if(value.id()==ID_initializer_list &&
         value.operands().size()==1)
        *dest=do_initializer_rec(value.op0(), type, force_constant);
      else
        *dest=do_initializer_rec(value, type, force_constant);

      assert(full_type==follow(dest->type()));

      return; // done
    }

    // union? The component in the zero initializer might
    // not be the first one.
    if(full_type.id()==ID_union)
    {
      const union_typet &union_type=to_union_type(full_type);

      const union_typet::componentst &components=
        union_type.components();

      if(!components.empty())
      {
        const union_typet::componentt &component=
          union_type.components().front();

        union_exprt union_expr(type);
        union_expr.op()=
          zero_initializer(
            component.type(),
            value.source_location(),
            *this,
            get_message_handler());
        union_expr.add_source_location()=value.source_location();
        union_expr.set_component_name(component.get_name());
        *dest=union_expr;
      }
    }

    // see what initializer we are given
    if(value.id()==ID_initializer_list)
    {
      *dest=do_initializer_rec(value, type, force_constant);
      return; // done
    }
    else if(value.id()==ID_string_constant)
    {
      // We stop for initializers that are string-constants,
      // which are like arrays. We only do so if we are to
      // initialize an array of scalars.
      if(full_type.id()==ID_array &&
         (follow(full_type.subtype()).id()==ID_signedbv ||
          follow(full_type.subtype()).id()==ID_unsignedbv))
      {
        *dest=do_initializer_rec(value, type, force_constant);
        return; // done
      }
    }
    else if(follow(value.type())==full_type)
    {
      // a struct/union/vector can be initialized directly with
      // an expression of the right type. This doesn't
      // work with arrays, unfortunately.
      if(full_type.id()==ID_struct ||
         full_type.id()==ID_union ||
         full_type.id()==ID_vector)
      {
        *dest=value;
        return; // done
      }
    }

    assert(full_type.id()==ID_struct ||
           full_type.id()==ID_union ||
           full_type.id()==ID_array ||
           full_type.id()==ID_vector);

    // we are initializing a compound type, and enter it!
    // this may change the type, full_type might not be valid anymore
    const typet dest_type=full_type;
    designator_enter(type, designator);

    if(dest->operands().empty())
    {
      err_location(value);
      error() << "cannot initialize type `"
              << to_string(dest_type) << "' using value `"
              << to_string(value) << "'" << eom;
      throw 0;
    }

    dest=&(dest->op0());

    // we run into another loop iteration
  }
}
Пример #11
0
bool c_typecheck_baset::zero_initializer(exprt &value, const typet &type) const
{
  const std::string &type_id = type.id_string();

  if(type_id == "bool")
  {
    value.make_false();
    return false;
  }
  if(
    type_id == "unsignedbv" || type_id == "signedbv" || type_id == "floatbv" ||
    type_id == "fixedbv" || type_id == "pointer")
  {
    value = gen_zero(type);
    return false;
  }
  else if(type_id == "code")
    return false;
  else if(type_id == "c_enum" || type_id == "incomplete_c_enum")
  {
    value = exprt("constant", type);
    value.value(i2string(0));
    return false;
  }
  else if(type_id == "array")
  {
    const array_typet &array_type = to_array_type(type);

    exprt tmpval;
    if(zero_initializer(tmpval, array_type.subtype()))
      return true;

    const exprt &size_expr = array_type.size();

    if(size_expr.id() == "infinity")
    {
    }
    else
    {
      mp_integer size;

      if(to_integer(size_expr, size))
        return true;

      // Permit GCC zero sized arrays; disallow negative sized arrays.
      // Cringe slightly when doing it though.
      if(size < 0)
        return true;
    }

    value = exprt("array_of", type);
    value.move_to_operands(tmpval);

    return false;
  }
  else if(type_id == "struct")
  {
    const irept::subt &components = type.components().get_sub();

    value = exprt("struct", type);

    forall_irep(it, components)
    {
      exprt tmp;

      if(zero_initializer(tmp, (const typet &)it->type()))
        return true;

      value.move_to_operands(tmp);
    }

    return false;
  }
Пример #12
0
void c_typecheck_baset::do_designated_initializer(
  exprt &result,
  designatort &designator,
  const exprt &value,
  bool force_constant)
{
  assert(!designator.empty());
  
  if(value.id()==ID_designated_initializer)
  {
    assert(value.operands().size()==1);

    designator=    
      make_designator(
        designator.front().type,
        static_cast<const exprt &>(value.find(ID_designator)));
        
    assert(!designator.empty());
  
    return do_designated_initializer(
      result, designator, value.op0(), force_constant);
  }
  
  exprt *dest=&result;

  // first phase: follow given designator

  for(unsigned i=0; i<designator.size(); i++)
  {
    unsigned index=designator[i].index;
    const typet &type=designator[i].type;
    
    assert(type.id()!=ID_symbol);

    if(type.id()==ID_array ||
       type.id()==ID_struct ||
       type.id()==ID_incomplete_array)
    {
      if(index>=dest->operands().size())
      {
        if(type.id()==ID_incomplete_array)
        {
          exprt zero=zero_initializer(type.subtype(), value.location());
          dest->operands().resize(integer2long(index)+1, zero);
        }
        else
        {
          err_location(value);
          str << "index designator " << index
              << " out of bounds (" << dest->operands().size() << ")";
          throw 0;
        }
      }

      dest=&(dest->operands()[integer2long(index)]);
    }
    else if(type.id()==ID_union)
    {
      // union initialization is quite special
      const union_typet &union_type=to_union_type(type);
      const union_typet::componentt &component=union_type.components()[index];

      // build a union expression from the argument
      exprt union_expr(ID_union, type);
      union_expr.operands().resize(1);
      union_expr.op0()=zero_initializer(component.type(), value.location());
      union_expr.location()=value.location();
      union_expr.set(ID_component_name, component.get_name());

      *dest=union_expr;
      dest=&(dest->op0());
    }
    else
      assert(false);
  }
  
  // second phase: assign value
  // for this, we may need to go down, adding to the designator
  
  while(true)
  {
    // see what type we have to initialize

    typet type=follow(designator.back().subtype);
    assert(type.id()!=ID_symbol);

    // do we initialize a scalar?
    if(type.id()!=ID_struct &&
       type.id()!=ID_union &&
       type.id()!=ID_array &&
       type.id()!=ID_incomplete_array)
    {
      // The initializer for a scalar shall be a single expression,
      // * optionally enclosed in braces. *
      
      if(value.id()==ID_initializer_list &&
         value.operands().size()==1)
        *dest=do_initializer_rec(value.op0(), type, force_constant);
      else
        *dest=do_initializer_rec(value, type, force_constant);

      assert(type==follow(dest->type()));
      
      return; // done
    }

    // see what initializer we are given
    if(value.id()==ID_initializer_list)
    {
      *dest=do_initializer_rec(value, type, force_constant);
      return; // done
    }
    else if(value.id()==ID_string_constant)
    {
      // We stop for initializers that are string-constants,
      // which are like arrays. We only do so if we are to
      // initialize an array of scalars.
      if((type.id()==ID_array || type.id()==ID_incomplete_array) &&
         (follow(type.subtype()).id()==ID_signedbv ||
          follow(type.subtype()).id()==ID_unsignedbv))
      {
        *dest=do_initializer_rec(value, type, force_constant);
        return; // done
      }
    }
    else if(follow(value.type())==type)
    {
      // a struct/union can be initialized directly with
      // an expression of the right type. This doesn't
      // work with arrays, unfortunately.
      if(type.id()==ID_struct || type.id()==ID_union)
      {
        *dest=value;
        return; // done
      }
    }
    
    // we are initializing a compound type, and enter it!
    designator_enter(type, designator);
    
    assert(!dest->operands().empty());
    dest=&(dest->op0());

    // we run into another loop iteration
  }
}
Пример #13
0
exprt c_typecheck_baset::zero_initializer(
  const typet &type,
  const locationt &location)
{
  const irep_idt &type_id=type.id();
  
  if(type_id==ID_bool)
  {
    exprt result=false_exprt();
    result.location()=location;
    return result;
  }
  else if(type_id==ID_unsignedbv ||
          type_id==ID_signedbv ||
          type_id==ID_floatbv ||
          type_id==ID_fixedbv ||
          type_id==ID_pointer)
  {
    exprt result=gen_zero(type);
    result.location()=location;
    return result;
  }
  else if(type_id==ID_code)
  {
    err_location(location);
    throw "cannot zero-initialize code-type";
  }
  else if(type_id==ID_c_enum ||
          type_id==ID_incomplete_c_enum)
  {
    constant_exprt value(type);
    value.set_value(ID_0);
    value.location()=location;
    return value;
  }
  else if(type_id==ID_array)
  {
    const array_typet &array_type=to_array_type(type);
    exprt tmpval=zero_initializer(array_type.subtype(), location);

    mp_integer array_size;

    if(array_type.size().id()==ID_infinity)
    {
      exprt value(ID_array_of, type);
      value.copy_to_operands(tmpval);
      value.location()=location;
      return value;
    }
    else if(to_integer(array_type.size(), array_size))
    {
      err_location(location);
      str << "failed to zero-initialize array of non-fixed size `"
          << to_string(array_type.size()) << "'";
      throw 0;
    }
      
    if(array_size<0)
    {
      err_location(location);
      throw "failed to zero-initialize array of with negative size";
    }

    exprt value(ID_array, type);
    value.operands().resize(integer2long(array_size), tmpval);
    value.location()=location;

    return value;
  }
  else if(type_id==ID_incomplete_array)
  {
    // we initialize this with an empty array

    exprt value(ID_array, type);
    value.type().id(ID_array);
    value.type().set(ID_size, gen_zero(size_type()));
    value.location()=location;

    return value;
  }
  else if(type_id==ID_struct)
  {
    const struct_typet::componentst &components=
      to_struct_type(type).components();

    exprt value(ID_struct, type);
    
    value.operands().reserve(components.size());

    for(struct_typet::componentst::const_iterator
        it=components.begin();
        it!=components.end();
        it++)
      value.copy_to_operands(zero_initializer(it->type(), location));

    value.location()=location;

    return value;
  }
  else if(type_id==ID_union)
  {
    const union_typet::componentst &components=
      to_union_type(type).components();

    exprt value(ID_union, type);

    if(components.empty())
      return value; // stupid empty union

    value.set(ID_component_name, components.front().get(ID_name));
    value.copy_to_operands(
      zero_initializer(components.front().type(), location));
    value.location()=location;

    return value;
  }
  else if(type_id==ID_symbol)
    return zero_initializer(follow(type), location);
  else
  {
    err_location(location);
    str << "Failed to zero-initialize `" << to_string(type)
        << "'";
    throw 0;
  }
}