Example #1
0
void goto_convertt::read(exprt &expr, goto_programt &dest)
{
  if(expr.is_constant())
    return;

  if(expr.id()=="symbol")
  {
    // see if we already renamed it

  }

  symbolt &new_symbol=new_tmp_symbol(expr.type());

  codet assignment("assign");
  assignment.reserve_operands(2);
  assignment.copy_to_operands(symbol_expr(new_symbol));
  assignment.move_to_operands(expr);

  goto_programt tmp_program;
  convert(assignment, tmp_program);

  dest.destructive_append(tmp_program);

  expr=symbol_expr(new_symbol);
}
Example #2
0
void static_lifetime_init(
  const contextt &context,
  codet &dest)
{
  dest=code_blockt();

  // Do assignments based on "value".
  context.foreach_operand_in_order(
    [&dest] (const symbolt& s)
    {
      if(s.static_lifetime)
        init_variable(dest, s);
    }
  );

  // call designated "initialization" functions
  context.foreach_operand_in_order(
    [&dest] (const symbolt& s)
    {
      if(s.type.initialization() && s.type.is_code())
      {
        code_function_callt function_call;
        function_call.function() = symbol_expr(s);
        dest.move_to_operands(function_call);
      }
    }
  );
}
Example #3
0
void goto_convertt::make_temp_symbol(
  exprt &expr,
  goto_programt &dest)
{
  const locationt location=expr.find_location();

  symbolt &new_symbol=new_tmp_symbol(expr.type());

  code_assignt assignment;
  assignment.lhs()=symbol_expr(new_symbol);
  assignment.rhs()=expr;
  assignment.location()=location;

  convert(assignment, dest);

  expr=symbol_expr(new_symbol);
}
Example #4
0
void invariant_propagationt::get_objects(
  const symbolt &symbol,
  object_listt &dest)
{
  std::list<exprt> object_list;

  get_objects_rec(symbol_expr(symbol), object_list);
  
  for(std::list<exprt>::const_iterator
      it=object_list.begin();
      it!=object_list.end();
      it++)
    dest.push_back(object_store.add(*it));
}
Example #5
0
code_function_callt get_destructor(
  const namespacet &ns,
  const typet &type)
{
  if(type.id()==ID_symbol)
  {
    return get_destructor(ns, ns.follow(type));
  }
  else if(type.id()==ID_struct)
  {
    const struct_typet &struct_type=to_struct_type(type);

    const struct_typet::componentst &components=
      struct_type.components();

    for(struct_typet::componentst::const_iterator
        it=components.begin();
        it!=components.end();
        it++)
    {
      if(it->type().id()==ID_code)
      {
        const code_typet &code_type=to_code_type(it->type());
        
        if(code_type.return_type().id()==ID_destructor &&
           code_type.parameters().size()==1)
        {
          const typet &arg_type=code_type.parameters().front().type();
          
          if(arg_type.id()==ID_pointer &&
             ns.follow(arg_type.subtype())==type)
          {
            exprt symbol_expr(ID_symbol, it->type());
            symbol_expr.set(ID_identifier, it->get(ID_name));      

            code_function_callt function_call;
            function_call.function()=symbol_expr;
            
            return function_call;
          }
        }
      }
    }
  }

  return static_cast<const code_function_callt &>(get_nil_irep());
}
Example #6
0
void termination_baset::replace_nondet_sideeffects(exprt &expr)
{
  if(expr.id()=="sideeffect" &&
     expr.get("statement")=="nondet")
  {
    symbolt symbol;
    symbol.name=std::string("termination::nondet")+i2string(++nondet_counter);
    symbol.base_name=std::string("nondet")+i2string(nondet_counter);
    symbol.type=expr.type();

    expr=symbol_expr(symbol);
    shadow_context.move(symbol);
  }
  else
    Forall_operands(it, expr)
      replace_nondet_sideeffects(*it);
}
Example #7
0
code_function_callt get_destructor(
  const namespacet &ns,
  const typet &type)
{
  if(type.id()==ID_symbol)
  {
    return get_destructor(ns, ns.follow(type));
  }
  else if(type.id()==ID_struct)
  {
    const exprt &methods=static_cast<const exprt&>(type.find(ID_methods));

    forall_operands(it, methods)
    {
      if(it->type().id()==ID_code)
      {
        const code_typet &code_type=to_code_type(it->type());

        if(code_type.return_type().id()==ID_destructor &&
           code_type.parameters().size()==1)
        {
          const typet &arg_type=code_type.parameters().front().type();

          if(arg_type.id()==ID_pointer &&
             ns.follow(arg_type.subtype())==type)
          {
            exprt symbol_expr(ID_symbol, it->type());
            symbol_expr.set(ID_identifier, it->get(ID_name));

            code_function_callt function_call;
            function_call.function()=symbol_expr;

            return function_call;
          }
        }
      }
    }
  }

  return static_cast<const code_function_callt &>(get_nil_irep());
}
codet java_bytecode_convertt::convert_instructions(
  const instructionst &instructions,
  const code_typet &method_type)
{
  // Run a worklist algorithm, assuming that the bytecode has not
  // been tampered with. See "Leroy, X. (2003). Java bytecode
  // verification: algorithms and formalizations. Journal of Automated
  // Reasoning, 30(3-4), 235-269." for a more complete treatment.

  // first pass: get targets and map addresses to instructions
  
  struct converted_instructiont
  {
    converted_instructiont(
      const instructionst::const_iterator &it,
      const codet &_code):source(it), code(_code), done(false)
    {
    }

    instructionst::const_iterator source;
    std::list<unsigned> successors;
    std::set<unsigned> predecessors;
    codet code;
    stackt stack;
    bool done;
  };
  
  typedef std::map<unsigned, converted_instructiont> address_mapt;
  address_mapt address_map;
  std::set<unsigned> targets;

  for(instructionst::const_iterator
      i_it=instructions.begin();
      i_it!=instructions.end();
      i_it++)
  {
    std::pair<address_mapt::iterator, bool> a_entry=
      address_map.insert(std::make_pair(
          i_it->address,
          converted_instructiont(i_it, code_skipt())));
    assert(a_entry.second);
    // addresses are strictly increasing, hence we must have inserted
    // a new maximal key
    assert(a_entry.first==--address_map.end());

    if(i_it->statement!="goto" &&
       i_it->statement!="return" &&
       !(i_it->statement==patternt("?return")) &&
       i_it->statement!="athrow")
    {
      instructionst::const_iterator next=i_it;
      if(++next!=instructions.end())
        a_entry.first->second.successors.push_back(next->address);
    }

    if(i_it->statement=="goto" ||
       i_it->statement==patternt("if_?cmp??") ||
       i_it->statement==patternt("if??") ||
       i_it->statement=="ifnonnull" ||
       i_it->statement=="ifnull")
    {
      assert(!i_it->args.empty());

      const unsigned target=safe_string2unsigned(
        id2string(to_constant_expr(i_it->args[0]).get_value()));
      targets.insert(target);

      a_entry.first->second.successors.push_back(target);
    }
    else if(i_it->statement=="tableswitch" ||
            i_it->statement=="lookupswitch")
    {
      bool is_label=true;
      for(instructiont::argst::const_iterator
          a_it=i_it->args.begin();
          a_it!=i_it->args.end();
          a_it++, is_label=!is_label)
      {
        if(is_label)
        {
          const unsigned target=safe_string2unsigned(
            id2string(to_constant_expr(*a_it).get_value()));
          targets.insert(target);
          a_entry.first->second.successors.push_back(target);
        }
      }
    }
  }

  for(address_mapt::iterator
      it=address_map.begin();
      it!=address_map.end();
      ++it)
  {
    for(unsigned s : it->second.successors)
    {
      address_mapt::iterator a_it=address_map.find(s);
      assert(a_it!=address_map.end());

      a_it->second.predecessors.insert(it->first);
    }
  }

  std::set<unsigned> working_set;
  if(!instructions.empty())
    working_set.insert(instructions.front().address);

  while(!working_set.empty())
  {
    std::set<unsigned>::iterator cur=working_set.begin();
    address_mapt::iterator a_it=address_map.find(*cur);
    assert(a_it!=address_map.end());
    working_set.erase(cur);

    if(a_it->second.done) continue;
    working_set.insert(a_it->second.successors.begin(),
                       a_it->second.successors.end());

    instructionst::const_iterator i_it=a_it->second.source;
    stack.swap(a_it->second.stack);
    a_it->second.stack.clear();
    codet &c=a_it->second.code;

    assert(stack.empty() ||
           a_it->second.predecessors.size()<=1 ||
           has_prefix(stack.front().get_string(ID_C_base_name),
                      "$stack"));

    irep_idt statement=i_it->statement;
    exprt arg0=i_it->args.size()>=1?i_it->args[0]:nil_exprt();
    exprt arg1=i_it->args.size()>=2?i_it->args[1]:nil_exprt();

    const bytecode_infot &bytecode_info=get_bytecode_info(statement);

    // deal with _idx suffixes
    if(statement.size()>=2 &&
       statement[statement.size()-2]=='_' &&
       isdigit(statement[statement.size()-1]))
    {
      arg0=constant_exprt(
        std::string(id2string(statement), statement.size()-1, 1),
        integer_typet());
      statement=std::string(id2string(statement), 0, statement.size()-2);
    }
    
    exprt::operandst op=pop(bytecode_info.pop);
    exprt::operandst results;
    results.resize(bytecode_info.push, nil_exprt());
    
    if(statement=="aconst_null")
    {
      assert(results.size()==1);
      results[0]=gen_zero(java_reference_type(void_typet()));
    }
    else if(statement=="athrow")
    {
      assert(op.size()==1 && results.size()==1);
      side_effect_expr_throwt throw_expr;
      throw_expr.add_source_location()=i_it->source_location;
      throw_expr.copy_to_operands(op[0]);
      c=code_expressiont(throw_expr);
      results[0]=op[0];
    }
    else if(statement=="checkcast")
    {
      // checkcast throws an exception in case a cast of object
      // on stack to given type fails.
      // The stack isn't modified.
      assert(op.size()==1 && results.size()==1);
      results[0]=op[0];
    }
    else if(statement=="invokedynamic")
    {
      // not used in Java
      code_typet &code_type=to_code_type(arg0.type());
      const code_typet::parameterst &parameters(code_type.parameters());

      pop(parameters.size());

      const typet &return_type=code_type.return_type();

      if(return_type.id()!=ID_empty)
      {
        results.resize(1);
        results[0]=nil_exprt();
      }
    }
    else if(statement=="invokeinterface" ||
            statement=="invokespecial" ||
            statement=="invokevirtual" ||
            statement=="invokestatic")
    {
      const bool use_this(statement != "invokestatic");
      const bool is_virtual(
        statement == "invokevirtual" || statement == "invokeinterface");
      
      code_typet &code_type=to_code_type(arg0.type());
      code_typet::parameterst &parameters(code_type.parameters());

      if(use_this)
      {
        if(parameters.empty() || !parameters[0].get_this())
        {
          const empty_typet empty;
          pointer_typet object_ref_type(empty);
          code_typet::parametert this_p(object_ref_type);
          this_p.set_this();
          this_p.set_base_name("this");
          parameters.insert(parameters.begin(), this_p);
        }
      }

      code_function_callt call;
      call.add_source_location()=i_it->source_location;
      call.arguments() = pop(parameters.size());

      // double-check a bit      
      if(use_this)
      {
        const exprt &this_arg=call.arguments().front();
        assert(this_arg.type().id()==ID_pointer);
      }
      
      // do some type adjustment for the arguments,
      // as Java promotes arguments

      for(unsigned i=0; i<parameters.size(); i++)
      {
        const typet &type=parameters[i].type();
        if(type==java_boolean_type() ||
           type==java_char_type() ||
           type==java_byte_type() ||
           type==java_short_type())
        {
          assert(i<call.arguments().size());
          call.arguments()[i].make_typecast(type);
        }
      }
      
      // do some type adjustment for return values

      const typet &return_type=code_type.return_type();

      if(return_type.id()!=ID_empty)
      {
        // return types are promoted in Java
        call.lhs()=tmp_variable("return", return_type);
        exprt promoted=java_bytecode_promotion(call.lhs());
        results.resize(1);
        results[0]=promoted;
      }

      assert(arg0.id()==ID_virtual_function);

      // does the function symbol exist?
      irep_idt id=arg0.get(ID_identifier);

      if(symbol_table.symbols.find(id)==symbol_table.symbols.end())
      {
        // no, create stub
        symbolt symbol;
        symbol.name=id;
        symbol.base_name=arg0.get(ID_C_base_name);
        symbol.type=arg0.type();
        symbol.value.make_nil();
        symbol.mode=ID_java;
        symbol_table.add(symbol);
      }

      if(is_virtual)
      {
        // dynamic binding
        assert(use_this);
        assert(!call.arguments().empty());
        call.function()=arg0;
      }
      else
      {
        // static binding
	/*if(id == "java::java.lang.String.charAt:(I)C")
	  call.function()=symbol_exprt("java::__CPROVER_uninterpreted_char_at", arg0.type());
	  else*/
	  call.function()=symbol_exprt(arg0.get(ID_identifier), arg0.type());

      }

      call.function().add_source_location()=i_it->source_location;
      c = call;
      
    }
    else if(statement=="return")
    {
      assert(op.empty() && results.empty());
      c=code_returnt();
    }
    else if(statement==patternt("?return"))
    {
      // Return types are promoted in java, so this might need
      // conversion.
      assert(op.size()==1 && results.empty());
      exprt r=op[0];
      if(r.type()!=method_return_type) r=typecast_exprt(r, method_return_type);
      c=code_returnt(r);
    }
    else if(statement==patternt("?astore"))
    {
      assert(op.size()==3 && results.empty());
      
      char type_char=statement[0];
      
      exprt pointer=
        typecast_exprt(op[0], java_array_type(type_char));

      const dereference_exprt deref(pointer, pointer.type().subtype());

      const member_exprt data_ptr(
        deref, "data", pointer_typet(java_type_from_char(type_char)));

      plus_exprt data_plus_offset(data_ptr, op[1], data_ptr.type());
      typet element_type=data_ptr.type().subtype();
      const dereference_exprt element(data_plus_offset, element_type);

      c=code_assignt(element, op[2]);
    }
    else if(statement==patternt("?store"))
    {
      // store value into some local variable
      assert(op.size()==1 && results.empty());

      exprt var=variable(arg0, statement[0]);
      
      const bool is_array('a' == statement[0]);
      
      if(is_array)
        var.type()=op[0].type();

      c=code_assignt(var, op[0]);
    }
    else if(statement==patternt("?aload"))
    {
      assert(op.size() == 2 && results.size() == 1);
      
      char type_char=statement[0];

      exprt pointer=
        typecast_exprt(op[0], java_array_type(type_char));

      const dereference_exprt deref(pointer, pointer.type().subtype());

      const member_exprt data_ptr(
        deref, "data", pointer_typet(java_type_from_char(type_char)));

      plus_exprt data_plus_offset(data_ptr, op[1], data_ptr.type());
      typet element_type=data_ptr.type().subtype();
      dereference_exprt element(data_plus_offset, element_type);

      results[0]=java_bytecode_promotion(element);
    }
    else if(statement==patternt("?load"))
    {
      // load a value from a local variable
      results[0]=variable(arg0, statement[0]);
    }
    else if(statement=="ldc" || statement=="ldc_w" ||
            statement=="ldc2" || statement=="ldc2_w")
    {
      assert(op.empty() && results.size()==1);
      
      // 1) Pushing a String causes a reference to a java.lang.String object
      // to be constructed and pushed onto the operand stack.

      // 2) Pushing an int or a float causes a primitive value to be pushed
      // onto the stack.
      
      // 3) Pushing a Class constant causes a reference to a java.lang.Class
      // to be pushed onto the operand stack
      
      if(arg0.id()==ID_java_string_literal)
      {
        // these need to be references to java.lang.String
        results[0]=arg0;
        symbol_typet string_type("java::java.lang.String");
        results[0].type()=pointer_typet(string_type);
      }
      else if(arg0.id()==ID_type)
      {
        irep_idt class_id=arg0.type().get(ID_identifier);
        symbol_typet java_lang_Class("java::java.lang.Class");
        symbol_exprt symbol_expr(id2string(class_id)+"@class_model", java_lang_Class);
        address_of_exprt address_of_expr(symbol_expr);
        results[0]=address_of_expr;
      }
      else if(arg0.id()==ID_constant)
      {
        results[0]=arg0;
      }
      else
      {
        error() << "unexpected ldc argument" << eom;
        throw 0;
      }
      
    }
    else if(statement=="goto" || statement=="goto_w")
    {
      assert(op.empty() && results.empty());
      irep_idt number=to_constant_expr(arg0).get_value();
      code_gotot code_goto(label(number));
      c=code_goto;
    }
    else if(statement=="iconst_m1")
    {
      assert(results.size()==1);
      results[0]=from_integer(-1, java_int_type());
    }
    else if(statement==patternt("?const"))
    {
      assert(results.size() == 1);

      const char type_char=statement[0];
      const bool is_double('d' == type_char);
      const bool is_float('f' == type_char);

      if(is_double || is_float)
      {
        const ieee_float_spect spec(
            is_float ?
                ieee_float_spect::single_precision() :
                ieee_float_spect::double_precision());

        ieee_floatt value(spec);
        const typet &arg_type(arg0.type());
        if(ID_integer == arg_type.id())
          value.from_integer(arg0.get_int(ID_value));
        else
          value.from_expr(to_constant_expr(arg0));

        results[0] = value.to_expr();
      }
      else
      {
        const unsigned int value(arg0.get_unsigned_int(ID_value));
        const typet type=java_type_from_char(statement[0]);
        results[0] = as_number(value, type);
      }
    }
    else if(statement==patternt("?ipush"))
    {
      assert(results.size()==1);
      results[0]=typecast_exprt(arg0, java_int_type());
    }
    else if(statement==patternt("if_?cmp??"))
    {
      irep_idt number=to_constant_expr(arg0).get_value();
      assert(op.size()==2 && results.empty());

      code_ifthenelset code_branch;
      const irep_idt cmp_op=get_if_cmp_operator(statement);
      
      binary_relation_exprt condition(op[0], cmp_op, op[1]);

      cast_if_necessary(condition);
      code_branch.cond()=condition;
      code_branch.then_case()=code_gotot(label(number));
      code_branch.then_case().add_source_location()=i_it->source_location;
      code_branch.add_source_location()=i_it->source_location;
      
      c=code_branch;
    }
    else if(statement==patternt("if??"))
    {
      const irep_idt id=
        statement=="ifeq"?ID_equal:
        statement=="ifne"?ID_notequal:
        statement=="iflt"?ID_lt:
        statement=="ifge"?ID_ge:
        statement=="ifgt"?ID_gt:
        statement=="ifle"?ID_le:
        (assert(false), "");

      irep_idt number=to_constant_expr(arg0).get_value();
      assert(op.size()==1 && results.empty());

      code_ifthenelset code_branch;
      code_branch.cond()=binary_relation_exprt(op[0], id, gen_zero(op[0].type()));
      code_branch.cond().add_source_location()=i_it->source_location;
      code_branch.then_case()=code_gotot(label(number));
      code_branch.then_case().add_source_location()=i_it->source_location;
      code_branch.add_source_location()=i_it->source_location;

      c=code_branch;
    }
    else if(statement==patternt("ifnonnull"))
    {
      irep_idt number=to_constant_expr(arg0).get_value();
      assert(op.size()==1 && results.empty());
      code_ifthenelset code_branch;
      const typecast_exprt lhs(op[0], pointer_typet());
      const exprt rhs(gen_zero(lhs.type()));
      code_branch.cond()=binary_relation_exprt(lhs, ID_notequal, rhs);
      code_branch.then_case()=code_gotot(label(number));
      code_branch.then_case().add_source_location()=i_it->source_location;
      code_branch.add_source_location()=i_it->source_location;

      c=code_branch;
    }
    else if(statement==patternt("ifnull"))
    {
      assert(op.size()==1 && results.empty());
      irep_idt number=to_constant_expr(arg0).get_value();
      code_ifthenelset code_branch;
      const typecast_exprt lhs(op[0], pointer_typet(empty_typet()));
      const exprt rhs(gen_zero(lhs.type()));
      code_branch.cond()=binary_relation_exprt(lhs, ID_equal, rhs);
      code_branch.then_case()=code_gotot(label(number));
      code_branch.then_case().add_source_location()=i_it->source_location;
      code_branch.add_source_location()=i_it->source_location;

      c=code_branch;
    }
    else if(statement=="iinc")
    {
      code_assignt code_assign;
      code_assign.lhs()=variable(arg0, 'i');
      code_assign.rhs()=plus_exprt(
                          variable(arg0, 'i'),
                          typecast_exprt(arg1, java_int_type()));
      c=code_assign;
    }
    else if(statement==patternt("?xor"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=bitxor_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?or"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=bitor_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?and"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=bitand_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?shl"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=shl_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?shr"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=ashr_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?ushr"))
    {
      assert(op.size()==2 && results.size()==1);
      const typet type(java_type_from_char(statement[0]));

      const unsigned int width(type.get_unsigned_int(ID_width));
      typet target=unsigned_long_int_type();
      target.set(ID_width, width);

      const typecast_exprt lhs(op[0], target);
      const typecast_exprt rhs(op[1], target);

      results[0]=lshr_exprt(lhs, rhs);
    }
    else if(statement==patternt("?add"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=plus_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?sub"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=minus_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?div"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=div_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?mul"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=mult_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?neg"))
    {
      assert(op.size()==1 && results.size()==1);
      results[0]=unary_minus_exprt(op[0], op[0].type());
    }
    else if(statement==patternt("?rem"))
    {
      assert(op.size()==2 && results.size()==1);
      if(statement=="frem" || statement=="drem")
        results[0]=rem_exprt(op[0], op[1]);
      else
        results[0]=mod_exprt(op[0], op[1]);
    }
    else if(statement==patternt("?cmp"))
    {
      assert(op.size() == 2 && results.size() == 1);

      // The integer result on the stack is:
      //  0 if op[0] equals op[1]
      // -1 if op[0] is less than op[1]
      //  1 if op[0] is greater than op[1]

      const typet t=java_int_type();

      results[0]=
        if_exprt(binary_relation_exprt(op[0], ID_equal, op[1]), gen_zero(t),
        if_exprt(binary_relation_exprt(op[0], ID_gt, op[1]), from_integer(1, t),
        from_integer(-1, t)));
    }
    else if(statement==patternt("?cmp?"))
    {
      assert(op.size()==2 && results.size()==1);
      const floatbv_typet type(to_floatbv_type(java_type_from_char(statement[0])));
      const ieee_float_spect spec(type);
      const ieee_floatt nan(ieee_floatt::NaN(spec));
      const constant_exprt nan_expr(nan.to_expr());
      const int nan_value(statement[4] == 'l' ? -1 : 1);
      const typet result_type(java_int_type());
      const exprt nan_result(from_integer(nan_value, result_type));

      // (value1 == NaN || value2 == NaN) ? nan_value : value1  < value2 ? -1 : value2 < value1  1 ? 1 : 0;
      // (value1 == NaN || value2 == NaN) ? nan_value : value1 == value2 ? 0  : value1 < value2 -1 ? 1 : 0;

      results[0]=
        if_exprt(or_exprt(ieee_float_equal_exprt(nan_expr, op[0]), ieee_float_equal_exprt(nan_expr, op[1])), nan_result,
        if_exprt(ieee_float_equal_exprt(op[0], op[1]), gen_zero(result_type),
        if_exprt(binary_relation_exprt(op[0], ID_lt, op[1]), from_integer(-1, result_type), from_integer(1, result_type))));
    }
    else if(statement==patternt("?cmpl"))
    {
      assert(op.size()==2 && results.size()==1);
      results[0]=binary_relation_exprt(op[0], ID_lt, op[1]);
    }
    else if(statement=="dup")
    {
      assert(op.size()==1 && results.size()==2);
      results[0]=results[1]=op[0];
    }
    else if(statement=="dup_x1")
    {
      assert(op.size()==2 && results.size()==3);
      results[0]=op[1];
      results[1]=op[0];
      results[2]=op[1];
    }
    else if(statement=="dup_x2")
    {
      assert(op.size()==3 && results.size()==4);
      results[0]=op[2];
      results[1]=op[0];
      results[2]=op[1];
      results[3]=op[2];
    }
    // dup2* behaviour depends on the size of the operands on the
    // stack
    else if(statement=="dup2")
    {
      assert(!stack.empty() && results.empty());

      if(stack.back().type().get_unsigned_int(ID_width)==32)
        op=pop(2);
      else
        op=pop(1);

      results.insert(results.end(), op.begin(), op.end());
      results.insert(results.end(), op.begin(), op.end());
    }
    else if(statement=="dup2_x1")
    {
      assert(!stack.empty() && results.empty());

      if(stack.back().type().get_unsigned_int(ID_width)==32)
        op=pop(3);
      else
        op=pop(2);

      results.insert(results.end(), op.begin()+1, op.end());
      results.insert(results.end(), op.begin(), op.end());
    }
    else if(statement=="dup2_x2")
    {
      assert(!stack.empty() && results.empty());

      if(stack.back().type().get_unsigned_int(ID_width)==32)
        op=pop(2);
      else
        op=pop(1);

      assert(!stack.empty());
      exprt::operandst op2;

      if(stack.back().type().get_unsigned_int(ID_width)==32)
        op2=pop(2);
      else
        op2=pop(1);

      results.insert(results.end(), op.begin(), op.end());
      results.insert(results.end(), op2.begin(), op2.end());
      results.insert(results.end(), op.begin(), op.end());
    }
    else if(statement=="dconst")
    {
      assert(op.empty() && results.size()==1);
    }
    else if(statement=="fconst")
    {
      assert(op.empty() && results.size()==1);
    }
    else if(statement=="getfield")
    {
      assert(op.size()==1 && results.size()==1);
      results[0]=to_member(op[0], arg0);
    }
    else if(statement=="getstatic")
    {
      assert(op.empty() && results.size()==1);
      symbol_exprt symbol_expr(arg0.type());
      symbol_expr.set_identifier(arg0.get_string(ID_class)+"."+arg0.get_string(ID_component_name));
      results[0]=symbol_expr;
    }
    else if(statement=="putfield")
    {
      assert(op.size()==2 && results.size()==0);
      c = code_assignt(to_member(op[0], arg0), op[1]);
    }
    else if(statement=="putstatic")
    {
      assert(op.size()==1 && results.empty());
      symbol_exprt symbol_expr(arg0.type());
      symbol_expr.set_identifier(arg0.get_string(ID_class)+"."+arg0.get_string(ID_component_name));
      c=code_assignt(symbol_expr, op[0]);
    }
    else if(statement==patternt("?2?")) // i2c etc.
    {
      assert(op.size()==1 && results.size()==1);
      results[0]=typecast_exprt(op[0], java_type_from_char(statement[2]));
    }
    else if(statement=="new")
    {
      // use temporary since the stack symbol might get duplicated
      assert(op.empty() && results.size()==1);
      const pointer_typet ref_type(arg0.type());
      exprt java_new_expr=side_effect_exprt(ID_java_new, ref_type);

      if(!i_it->source_location.get_line().empty())
        java_new_expr.add_source_location()=i_it->source_location;

      const exprt tmp=tmp_variable("new", ref_type);
      c=code_assignt(tmp, java_new_expr);
      results[0]=tmp;
    }
    else if(statement=="newarray" ||
            statement=="anewarray")
    {
      // the op is the array size
      assert(op.size()==1 && results.size()==1);

      char element_type;
      
      if(statement=="newarray")
      {
        irep_idt id=arg0.type().id();

        if(id==ID_bool)
          element_type='z';
        else if(id==ID_char)
          element_type='c';
        else if(id==ID_float)
          element_type='f';
        else if(id==ID_double)
          element_type='d';
        else if(id==ID_byte)
          element_type='b';
        else if(id==ID_short)
          element_type='s';
        else if(id==ID_int)
          element_type='i';
        else if(id==ID_long)
          element_type='j';
        else
          element_type='?';
      }
      else
        element_type='a';

      const pointer_typet ref_type=java_array_type(element_type);

      side_effect_exprt java_new_array(ID_java_new_array, ref_type);
      java_new_array.copy_to_operands(op[0]);

      if(!i_it->source_location.get_line().empty())
        java_new_array.add_source_location()=i_it->source_location;

      const exprt tmp=tmp_variable("newarray", ref_type);
      c=code_assignt(tmp, java_new_array);
      results[0]=tmp;
    }
    else if(statement=="multianewarray")
    {
      // The first argument is the type, the second argument is the dimension.
      // The size of each dimension is on the stack.
      irep_idt number=to_constant_expr(arg1).get_value();
      unsigned dimension=safe_c_str2unsigned(number.c_str());

      op=pop(dimension);
      assert(results.size()==1);

      // arg0.type()
      const pointer_typet ref_type=java_array_type('a');

      side_effect_exprt java_new_array(ID_java_new_array, ref_type);
      java_new_array.operands()=op;

      if(!i_it->source_location.get_line().empty())
        java_new_array.add_source_location()=i_it->source_location;

      const exprt tmp=tmp_variable("newarray", ref_type);
      c=code_assignt(tmp, java_new_array);
      results[0]=tmp;
    }
    else if(statement=="arraylength")
    {
      assert(op.size()==1 && results.size()==1);

      exprt pointer=
        typecast_exprt(op[0], java_array_type(statement[0]));

      const dereference_exprt array(pointer, pointer.type().subtype());
      assert(pointer.type().subtype().id()==ID_symbol);

      const member_exprt length(array, "length", java_int_type());

      results[0]=length;
    }
    else if(statement=="tableswitch" ||
            statement=="lookupswitch")
    {
      assert(op.size()==1 && results.size()==0);

      // we turn into switch-case
      code_switcht code_switch;
      code_switch.add_source_location()=i_it->source_location;
      code_switch.value()=op[0];
      code_blockt code_block;
      code_block.add_source_location()=i_it->source_location;

      bool is_label=true;
      for(instructiont::argst::const_iterator
          a_it=i_it->args.begin();
          a_it!=i_it->args.end();
          a_it++, is_label=!is_label)
      {
        if(is_label)
        {
          code_switch_caset code_case;
          code_case.add_source_location()=i_it->source_location;

          irep_idt number=to_constant_expr(*a_it).get_value();
          code_case.code()=code_gotot(label(number));
          code_case.code().add_source_location()=i_it->source_location;
        
          if(a_it==i_it->args.begin())
            code_case.set_default();
          else
          {
            instructiont::argst::const_iterator prev=a_it;
            prev--;
            code_case.case_op()=typecast_exprt(*prev, op[0].type());
            code_case.case_op().add_source_location()=i_it->source_location;
          }
          
          code_block.add(code_case);
        }
      }
      
      code_switch.body()=code_block;
      c=code_switch;
    }
    else if(statement=="pop" || statement=="pop2")
    {
      // these are skips
      c=code_skipt();

      // pop2 removes two single-word items from the stack (e.g. two
      // integers, or an integer and an object reference) or one
      // two-word item (i.e. a double or a long).
      // http://cs.au.dk/~mis/dOvs/jvmspec/ref-pop2.html
      if(statement=="pop2" &&
         op[0].type().get_unsigned_int(ID_width)==32)
        pop(1);
    }
    else if(statement=="instanceof")
    {
      assert(op.size()==1 && results.size()==1);

      results[0]=
        binary_predicate_exprt(op[0], "java_instanceof", arg0);
    }
    else
    {
      c=codet(statement);
      c.operands()=op;
    }
    
    if(!i_it->source_location.get_line().empty())
      c.add_source_location()=i_it->source_location;

    push(results);

    a_it->second.done=true;
    for(std::list<unsigned>::iterator
        it=a_it->second.successors.begin();
        it!=a_it->second.successors.end();
        ++it)
    {
      address_mapt::iterator a_it2=address_map.find(*it);
      assert(a_it2!=address_map.end());

      if(!stack.empty() && a_it2->second.predecessors.size()>1)
      {
        // copy into temporaries
        code_blockt more_code;

        // introduce temporaries when successor is seen for the first
        // time
        if(a_it2->second.stack.empty())
        {
          for(stackt::iterator s_it=stack.begin();
              s_it!=stack.end();
              ++s_it)
          {
            symbol_exprt lhs=tmp_variable("$stack", s_it->type());
            code_assignt a(lhs, *s_it);
            more_code.copy_to_operands(a);

            s_it->swap(lhs);
          }
        }
        else
        {
          assert(a_it2->second.stack.size()==stack.size());
          stackt::const_iterator os_it=a_it2->second.stack.begin();
          for(stackt::iterator s_it=stack.begin();
              s_it!=stack.end();
              ++s_it)
          {
            assert(has_prefix(os_it->get_string(ID_C_base_name),
                              "$stack"));
            symbol_exprt lhs=to_symbol_expr(*os_it);
            code_assignt a(lhs, *s_it);
            more_code.copy_to_operands(a);

            s_it->swap(lhs);
            ++os_it;
          }
        }

        if(results.empty())
        {
          more_code.copy_to_operands(c);
          c.swap(more_code);
        }
        else
        {
          c.make_block();
          forall_operands(o_it, more_code)
            c.copy_to_operands(*o_it);
        }
      }

      a_it2->second.stack=stack;
    }
  }

  // TODO: add exception handlers from exception table
  // review successor computation of athrow!
  code_blockt code;
  
  // temporaries
  for(const auto & var : tmp_vars)
  {
    code.add(code_declt(var));
  }

  for(const auto & it : address_map)
  {
    const unsigned address=it.first;
    assert(it.first==it.second.source->address);
    const codet &c=it.second.code;

    if(targets.find(address)!=targets.end())
      code.add(code_labelt(label(i2string(address)), c));
    else if(c.get_statement()!=ID_skip)
      code.add(c);
  }

  return code;
}
Example #9
0
void goto_inlinet::parameter_assignments(
  const locationt &location,
  const code_typet &code_type,
  const exprt::operandst &arguments,
  goto_programt &dest)
{
  // iterates over the operands
  exprt::operandst::const_iterator it1=arguments.begin();

  goto_programt::local_variablest local_variables;
  
  const code_typet::argumentst &argument_types=
    code_type.arguments();
  
  // iterates over the types of the arguments
  for(code_typet::argumentst::const_iterator
      it2=argument_types.begin();
      it2!=argument_types.end();
      it2++)
  {
    // if you run out of actual arguments there was a mismatch
    if(it1==arguments.end())
    {
      err_location(location);
      throw "function call: not enough arguments";
    }

    const exprt &argument=static_cast<const exprt &>(*it2);

    // this is the type the n-th argument should be
    const typet &arg_type=ns.follow(argument.type());

    const irep_idt &identifier=argument.cmt_identifier();

    if(identifier=="")
    {
      err_location(location);
      throw "no identifier for function argument";
    }

    {
      const symbolt &symbol=ns.lookup(identifier);

      goto_programt::targett decl=dest.add_instruction();
      decl->make_other();
      exprt tmp = code_declt(symbol_expr(symbol));
      migrate_expr(tmp, decl->code);
      decl->location=location;
      decl->function=location.get_function(); 
      decl->local_variables=local_variables;
    }

    local_variables.insert(identifier);
    
    // nil means "don't assign"
    if(it1->is_nil())
    {    
    }
    else
    {
      // this is the actual parameter
      exprt actual(*it1);

      // it should be the same exact type
      type2tc arg_type_2, actual_type_2;
      migrate_type(arg_type, arg_type_2);
      migrate_type(actual.type(), actual_type_2);
      if (!base_type_eq(arg_type_2, actual_type_2, ns))
      {
        const typet &f_argtype = ns.follow(arg_type);
        const typet &f_acttype = ns.follow(actual.type());
        
        // we are willing to do some conversion
        if((f_argtype.id()=="pointer" &&
            f_acttype.id()=="pointer") ||
           (f_argtype.is_array() &&
            f_acttype.id()=="pointer" &&
            f_argtype.subtype()==f_acttype.subtype()))
        {
          actual.make_typecast(arg_type);
        }
        else if((f_argtype.id()=="signedbv" ||
            f_argtype.id()=="unsignedbv" ||
            f_argtype.is_bool()) &&
           (f_acttype.id()=="signedbv" ||
            f_acttype.id()=="unsignedbv" ||
            f_acttype.is_bool()))  
        {
          actual.make_typecast(arg_type);
        }
        else
        {
          err_location(location);

          str << "function call: argument `" << identifier
              << "' type mismatch: got "
              << from_type(ns, identifier, it1->type())
              << ", expected "
              << from_type(ns, identifier, arg_type);
          throw 0;
        }
      }

      // adds an assignment of the actual parameter to the formal parameter
      code_assignt assignment(symbol_exprt(identifier, arg_type), actual);
      assignment.location()=location;

      dest.add_instruction(ASSIGN);
      dest.instructions.back().location=location;
      migrate_expr(assignment, dest.instructions.back().code);
      dest.instructions.back().local_variables=local_variables;
      dest.instructions.back().function=location.get_function();      
    }

    it1++;
  }

  if(it1!=arguments.end())
  {
    // too many arguments -- we just ignore that, no harm done
  }
}
Example #10
0
void c_typecheck_baset::add_argc_argv(const symbolt &main_symbol)
{
  const irept &arguments=
    main_symbol.type.find(ID_arguments);

  if(arguments.get_sub().size()==0)
    return;

  if(arguments.get_sub().size()!=2 &&
     arguments.get_sub().size()!=3)
  {
    err_location(main_symbol.location);
    throw "main expected to have no or two or three arguments";
  }

  symbolt *argc_new_symbol;
  
  const exprt &op0=static_cast<const exprt &>(arguments.get_sub()[0]);
  const exprt &op1=static_cast<const exprt &>(arguments.get_sub()[1]);

  {
    symbolt argc_symbol;

    argc_symbol.base_name="argc";
    argc_symbol.name="c::argc'";
    argc_symbol.type=op0.type();
    argc_symbol.is_static_lifetime=true;
    argc_symbol.is_lvalue=true;

    if(argc_symbol.type.id()!=ID_signedbv &&
       argc_symbol.type.id()!=ID_unsignedbv)
    {
      err_location(main_symbol.location);
      str << "argc argument expected to be integer type, but got `"
          << to_string(argc_symbol.type) << "'";
      throw 0;
    }

    move_symbol(argc_symbol, argc_new_symbol);
  }

  {
    if(op1.type().id()!=ID_pointer ||
       op1.type().subtype().id()!=ID_pointer)
    {
      err_location(main_symbol.location);
      str << "argv argument expected to be pointer-to-pointer type, "
             "but got `"
          << to_string(op1.type()) << "'";
      throw 0;
    }

    // we make the type of this thing an array of pointers
    typet argv_type=array_typet();
    argv_type.subtype()=op1.type().subtype();

    // need to add one to the size -- the array is terminated
    // with NULL
    exprt one_expr=from_integer(1, argc_new_symbol->type);
    
    exprt size_expr(ID_plus, argc_new_symbol->type);
    size_expr.copy_to_operands(symbol_expr(*argc_new_symbol), one_expr);
    argv_type.add(ID_size).swap(size_expr);

    symbolt argv_symbol;

    argv_symbol.base_name="argv'";
    argv_symbol.name="c::argv'";
    argv_symbol.type=argv_type;
    argv_symbol.is_static_lifetime=true;
    argv_symbol.is_lvalue=true;

    symbolt *argv_new_symbol;
    move_symbol(argv_symbol, argv_new_symbol);
  }
  
  if(arguments.get_sub().size()==3)
  {    
    symbolt envp_symbol;    
    envp_symbol.base_name="envp'";
    envp_symbol.name="c::envp'";
    envp_symbol.type=(static_cast<const exprt&>(arguments.get_sub()[2])).type();
    envp_symbol.is_static_lifetime=true;
    
    symbolt envp_size_symbol, *envp_new_size_symbol;
    envp_size_symbol.base_name="envp_size";
    envp_size_symbol.name="c::envp_size'";
    envp_size_symbol.type=op0.type(); // same type as argc!
    envp_size_symbol.is_static_lifetime=true;    
    move_symbol(envp_size_symbol, envp_new_size_symbol);        

    if(envp_symbol.type.id()!=ID_pointer)
    {
      err_location(main_symbol.location);
      str << "envp argument expected to be pointer type, but got `"
          << to_string(envp_symbol.type) << "'";
      throw 0;
    }
    
    exprt size_expr = symbol_expr(*envp_new_size_symbol);

    envp_symbol.type.id(ID_array);
    envp_symbol.type.add(ID_size).swap(size_expr);
    
    symbolt *envp_new_symbol;
    move_symbol(envp_symbol, envp_new_symbol);
  }
}
Example #11
0
void interpretert::execute_function_call()
{
  const code_function_callt &function_call=
    to_code_function_call(PC->code);

  // function to be called
  mp_integer a=evaluate_address(function_call.function());

  if(a==0)
    throw "function call to NULL";
  else if(a>=memory.size())
    throw "out-of-range function call";

  const memory_cellt &cell=memory[integer2long(a)];
  const irep_idt &identifier=cell.identifier;

  const goto_functionst::function_mapt::const_iterator f_it=
    goto_functions.function_map.find(identifier);

  if(f_it==goto_functions.function_map.end())
    throw "failed to find function "+id2string(identifier);
    
  // return value
  mp_integer return_value_address;

  if(function_call.lhs().is_not_nil())
    return_value_address=
      evaluate_address(function_call.lhs());
  else
    return_value_address=0;
    
  // values of the arguments
  std::vector<std::vector<mp_integer> > argument_values;
  
  argument_values.resize(function_call.arguments().size());
  
  for(std::size_t i=0; i<function_call.arguments().size(); i++)
    evaluate(function_call.arguments()[i], argument_values[i]);

  // do the call
      
  if(f_it->second.body_available)
  {
    call_stack.push(stack_framet());
    stack_framet &frame=call_stack.top();
    
    frame.return_PC=next_PC;
    frame.return_function=function;
    frame.old_stack_pointer=stack_pointer;
    frame.return_value_address=return_value_address;
    
    // local variables
    std::set<irep_idt> locals;
    get_local_identifiers(f_it->second, locals);
                    
    for(std::set<irep_idt>::const_iterator
        it=locals.begin();
        it!=locals.end();
        it++)
    {
      const irep_idt &id=*it;      
      const symbolt &symbol=ns.lookup(id);
      unsigned size=get_size(symbol.type);
      
      if(size!=0)
      {
        frame.local_map[id]=stack_pointer;

        for(unsigned i=0; i<stack_pointer; i++)
        {
          unsigned address=stack_pointer+i;
          if(address>=memory.size()) memory.resize(address+1);
          memory[address].value=0;
          memory[address].identifier=id;
          memory[address].offset=i;
        }
        
        stack_pointer+=size;
      }
    }
        
    // assign the arguments
    const code_typet::parameterst &parameters=
      to_code_type(f_it->second.type).parameters();

    if(argument_values.size()<parameters.size())
      throw "not enough arguments";

    for(unsigned i=0; i<parameters.size(); i++)
    {
      const code_typet::parametert &a=parameters[i];
      exprt symbol_expr(ID_symbol, a.type());
      symbol_expr.set(ID_identifier, a.get_identifier());
      assert(i<argument_values.size());
      assign(evaluate_address(symbol_expr), argument_values[i]);
    }

    // set up new PC
    function=f_it;
    next_PC=f_it->second.body.instructions.begin();    
  }
  else
    throw "no body for "+id2string(identifier);
}
Example #12
0
void string_instrumentationt::do_strerror(
  goto_programt &dest,
  goto_programt::targett it,
  code_function_callt &call)
{
  if(call.lhs().is_nil())
  {
    it->make_skip();
    return;
  }

  irep_idt identifier_buf="c::__strerror_buffer";
  irep_idt identifier_size="c::__strerror_buffer_size";

  if(context.symbols.find(identifier_buf)==context.symbols.end())
  {
    symbolt new_symbol_size;
    new_symbol_size.base_name="__strerror_buffer_size";
    new_symbol_size.pretty_name=new_symbol_size.base_name;
    new_symbol_size.name=identifier_size;
    new_symbol_size.mode="C";
    new_symbol_size.type=uint_type();
    new_symbol_size.is_statevar=true;
    new_symbol_size.lvalue=true;
    new_symbol_size.static_lifetime=true;

    array_typet type;
    type.subtype()=char_type();
    type.size()=symbol_expr(new_symbol_size);
    symbolt new_symbol_buf;
    new_symbol_buf.mode="C";
    new_symbol_buf.type=type;
    new_symbol_buf.is_statevar=true;
    new_symbol_buf.lvalue=true;
    new_symbol_buf.static_lifetime=true;
    new_symbol_buf.base_name="__strerror_buffer";
    new_symbol_buf.pretty_name=new_symbol_buf.base_name;
    new_symbol_buf.name="c::"+id2string(new_symbol_buf.base_name);

    context.move(new_symbol_buf);
    context.move(new_symbol_size);
  }

  const symbolt &symbol_size=ns.lookup(identifier_size);
  const symbolt &symbol_buf=ns.lookup(identifier_buf);

  goto_programt tmp;

  {  
    goto_programt::targett assignment1=tmp.add_instruction(ASSIGN);
    exprt nondet_size=side_effect_expr_nondett(uint_type());

    assignment1->code=code_assignt(symbol_expr(symbol_size), nondet_size);
    assignment1->location=it->location;
    
    goto_programt::targett assumption1=tmp.add_instruction();

    assumption1->make_assumption(binary_relation_exprt(
      symbol_expr(symbol_size), "notequal",
      gen_zero(symbol_size.type)));

    assumption1->location=it->location;
  }

  // return a pointer to some magic buffer
  exprt index=exprt("index", char_type());
  index.copy_to_operands(symbol_expr(symbol_buf), gen_zero(uint_type()));

  exprt ptr=exprt("address_of", pointer_typet());
  ptr.type().subtype()=char_type();
  ptr.copy_to_operands(index);

  // make that zero-terminated
  {
    goto_programt::targett assignment2=tmp.add_instruction(ASSIGN);
    assignment2->code=code_assignt(is_zero_string(ptr, true), true_exprt());
    assignment2->location=it->location;
  }

  // assign address
  {
    goto_programt::targett assignment3=tmp.add_instruction(ASSIGN);
    exprt rhs=ptr;
    make_type(rhs, call.lhs().type());
    assignment3->code=code_assignt(call.lhs(), rhs);
    assignment3->location=it->location;
  }

  it->make_skip();
  dest.insert_before_swap(it, tmp);
}
Example #13
0
void string_instrumentationt::invalidate_buffer(
  goto_programt &dest,
  goto_programt::const_targett target,
  const exprt &buffer,
  const typet &buf_type,
  const mp_integer &limit)
{
  irep_idt cntr_id="string_instrumentation::$counter";
  
  if(context.symbols.find(cntr_id)==context.symbols.end())
  {
    symbolt new_symbol;
    new_symbol.base_name="$counter";
    new_symbol.pretty_name=new_symbol.base_name;
    new_symbol.name=cntr_id;
    new_symbol.mode="C";
    new_symbol.type=uint_type();
    new_symbol.is_statevar=true;
    new_symbol.lvalue=true;
    new_symbol.static_lifetime=true;
    
    context.move(new_symbol);
  }
  
  const symbolt &cntr_sym=ns.lookup(cntr_id);
  
  // create a loop that runs over the buffer
  // and invalidates every element
  
  goto_programt::targett init=dest.add_instruction(ASSIGN);
  init->location=target->location;  
  init->code=code_assignt(symbol_expr(cntr_sym), gen_zero(cntr_sym.type));
  
  goto_programt::targett check=dest.add_instruction();
  check->location=target->location;  
  
  goto_programt::targett invalidate=dest.add_instruction(ASSIGN);
  invalidate->location=target->location;  
  
  goto_programt::targett increment=dest.add_instruction(ASSIGN);
  increment->location=target->location;  
  
  exprt plus("+", uint_type());
  plus.copy_to_operands(symbol_expr(cntr_sym));
  plus.copy_to_operands(gen_one(uint_type()));
  
  increment->code=code_assignt(symbol_expr(cntr_sym), plus);
  
  goto_programt::targett back=dest.add_instruction();
  back->location=target->location;  
  back->make_goto(check);
  back->guard=true_exprt();
  
  goto_programt::targett exit=dest.add_instruction();
  exit->location=target->location;  
  exit->make_skip();  
  
  exprt cnt_bs, bufp;
  
  if(buf_type.id()=="pointer")
    bufp = buffer;
  else
  {
    index_exprt index;
    index.array()=buffer;
    index.index()=gen_zero(uint_type());
    index.type()=buf_type.subtype();
    bufp = address_of_exprt(index);
  }
  
  exprt deref("dereference", buf_type.subtype());
  exprt b_plus_i("+", bufp.type());
  b_plus_i.copy_to_operands(bufp);
  b_plus_i.copy_to_operands(symbol_expr(cntr_sym));
  deref.copy_to_operands(b_plus_i);
  
  check->make_goto(exit);
  
  if(limit==0)
    check->guard=
          binary_relation_exprt(symbol_expr(cntr_sym), ">=", 
                                buffer_size(bufp));
  else
    check->guard=
          binary_relation_exprt(symbol_expr(cntr_sym), ">", 
                                from_integer(limit, uint_type()));
  
  exprt nondet=side_effect_expr_nondett(buf_type.subtype());
  invalidate->code=code_assignt(deref, nondet);
}
void cpp_typecheckt::typecheck_compound_declarator(
  const symbolt &symbol,
  const cpp_declarationt &declaration,
  cpp_declaratort &declarator,
  struct_typet::componentst &components,
  const irep_idt &access,
  bool is_static,
  bool is_typedef,
  bool is_mutable)
{
  bool is_cast_operator=
    declaration.type().id()=="cpp-cast-operator";

  if(is_cast_operator)
  {
    assert(declarator.name().get_sub().size()==2 &&
           declarator.name().get_sub().front().id()==ID_operator);

    typet type=static_cast<typet &>(declarator.name().get_sub()[1]);
    declarator.type().subtype()=type;

    irept name(ID_name);
    name.set(ID_identifier, "("+cpp_type2name(type)+")");
    declarator.name().get_sub().back().swap(name);
  }

  typet final_type=
    declarator.merge_type(declaration.type());

  // this triggers template elaboration
  elaborate_class_template(final_type);

  typecheck_type(final_type);
  
  cpp_namet cpp_name;
  cpp_name.swap(declarator.name());
  
  irep_idt base_name;
  
  if(cpp_name.is_nil())
  {
    // Yes, there can be members without name.
    base_name=irep_idt();
  }
  else if(cpp_name.is_simple_name())
  {
    base_name=cpp_name.get_base_name();
  }
  else
  {
    err_location(cpp_name.location());
    str << "declarator in compound needs to be simple name";
    throw 0;
  }


  bool is_method=!is_typedef && final_type.id()==ID_code;
  bool is_constructor=declaration.is_constructor();
  bool is_destructor=declaration.is_destructor();
  bool is_virtual=declaration.member_spec().is_virtual();
  bool is_explicit=declaration.member_spec().is_explicit();
  bool is_inline=declaration.member_spec().is_inline();

  final_type.set(ID_C_member_name, symbol.name);

  // first do some sanity checks

  if(is_virtual && !is_method)
  {
    err_location(cpp_name.location());
    str << "only methods can be virtual";
    throw 0;
  }

  if(is_inline && !is_method)
  {
    err_location(cpp_name.location());
    str << "only methods can be inlined";
    throw 0;
  }

  if(is_virtual && is_static)
  {
    err_location(cpp_name.location());
    str << "static methods cannot be virtual";
    throw 0;
  }

  if(is_cast_operator && is_static)
  {
    err_location(cpp_name.location());
    str << "cast operators cannot be static`";
    throw 0;
  }

  if(is_constructor && is_virtual)
  {
    err_location(cpp_name.location());
    str << "constructors cannot be virtual";
    throw 0;
  }

  if(!is_constructor && is_explicit)
  {
    err_location(cpp_name.location());
    str << "only constructors can be explicit";
    throw 0;
  }

  if(is_constructor &&
     base_name!=id2string(symbol.base_name))
  {
    err_location(cpp_name.location());
    str << "member function must return a value or void";
    throw 0;
  }

  if(is_destructor &&
     base_name!="~"+id2string(symbol.base_name))
  {
    err_location(cpp_name.location());
    str << "destructor with wrong name";
    throw 0;
  }

  // now do actual work

  struct_typet::componentt component;

  irep_idt identifier=
    language_prefix+
    cpp_scopes.current_scope().prefix+
    id2string(base_name);

  component.set(ID_name, identifier);
  component.type()=final_type;
  component.set(ID_access, access);
  component.set(ID_base_name, base_name);
  component.set(ID_pretty_name, base_name);
  component.location()=cpp_name.location();

  if(cpp_name.is_operator())
  {
    component.set("is_operator", true);
    component.type().set("#is_operator", true);
  }

  if(is_cast_operator)
    component.set("is_cast_operator", true);

  if(declaration.member_spec().is_explicit())
    component.set("is_explicit", true);

  typet &method_qualifier=
    (typet &)declarator.add("method_qualifier");

  if(is_static)
  {
    component.set(ID_is_static, true);
    component.type().set("#is_static", true);
  }

  if(is_typedef)
    component.set("is_type", true);

  if(is_mutable)
    component.set("is_mutable", true);

  exprt &value=declarator.value();
  irept &initializers=declarator.member_initializers();

  if(is_method)
  {
    component.set(ID_is_inline, declaration.member_spec().is_inline());

    // the 'virtual' name of the function
    std::string virtual_name=
    component.get_string(ID_base_name)+
      id2string(
        function_identifier(static_cast<const typet &>(component.find(ID_type))));

    if(method_qualifier.id()==ID_const)
      virtual_name += "$const";

    if(component.type().get(ID_return_type) == ID_destructor)
      virtual_name= "@dtor";
    
    // The method may be virtual implicitly.
    std::set<irep_idt> virtual_bases;

    for(struct_typet::componentst::const_iterator
        it=components.begin();
        it!=components.end();
        it++)
    {
      if(it->get_bool("is_virtual"))
      {
        if(it->get("virtual_name")==virtual_name)
        {
          is_virtual=true;
          const code_typet& code_type = to_code_type(it->type());
          assert(code_type.arguments().size()>0);
          const typet& pointer_type = code_type.arguments()[0].type();
          assert(pointer_type.id() == ID_pointer);
          virtual_bases.insert(pointer_type.subtype().get(ID_identifier));
        }
      }
    }

    if(!is_virtual)
    {
      typecheck_member_function(
        symbol.name, component, initializers,
        method_qualifier, value);

      if(!value.is_nil() && !is_static)
      {
        err_location(cpp_name.location());
        str << "no initialization allowed here";
        throw 0;
      }
    }
    else // virtual
    {
      component.type().set("#is_virtual", true);
      component.type().set("#virtual_name",virtual_name);

      // Check if it is a pure virtual method
      if(is_virtual)
      {
        if(value.is_not_nil() && value.id() == ID_constant)
        {
          mp_integer i;
          to_integer(value, i);
          if(i!=0)
          {
            err_location(declarator.name().location());
            str << "expected 0 to mark pure virtual method, got " << i;
          }
          component.set("is_pure_virtual", true);
          value.make_nil();
        }
      }

      typecheck_member_function(
        symbol.name,
        component,
        initializers,
        method_qualifier,
        value);

      // get the virtual-table symbol type
      irep_idt vt_name = "virtual_table::"+symbol.name.as_string();

      contextt::symbolst::iterator vtit =
        context.symbols.find(vt_name);

      if(vtit == context.symbols.end())
      {
        // first time: create a virtual-table symbol type 
        symbolt vt_symb_type;
        vt_symb_type.name= vt_name;
        vt_symb_type.base_name="virtual_table::"+symbol.base_name.as_string();
        vt_symb_type.pretty_name = vt_symb_type.base_name;
        vt_symb_type.mode=ID_cpp;
        vt_symb_type.module=module;
        vt_symb_type.location=symbol.location;
        vt_symb_type.type = struct_typet();
        vt_symb_type.type.set(ID_name, vt_symb_type.name);
        vt_symb_type.is_type = true;

        bool failed = context.move(vt_symb_type);
        assert(!failed);
        vtit = context.symbols.find(vt_name);

        // add a virtual-table pointer 
        struct_typet::componentt compo;
        compo.type() = pointer_typet(symbol_typet(vt_name));
        compo.set_name(symbol.name.as_string() +"::@vtable_pointer");
        compo.set(ID_base_name, "@vtable_pointer");
        compo.set(ID_pretty_name, symbol.base_name.as_string() +"@vtable_pointer");
        compo.set("is_vtptr", true);
        compo.set(ID_access, ID_public);
        components.push_back(compo);
        put_compound_into_scope(compo);
      }
      
      assert(vtit->second.type.id()==ID_struct);

      struct_typet &virtual_table=
        to_struct_type(vtit->second.type);

      component.set("virtual_name", virtual_name);
      component.set("is_virtual", is_virtual);

      // add an entry to the virtual table
      struct_typet::componentt vt_entry;
      vt_entry.type() = pointer_typet(component.type());
      vt_entry.set_name(vtit->first.as_string()+"::"+virtual_name);
      vt_entry.set(ID_base_name, virtual_name);
      vt_entry.set(ID_pretty_name, virtual_name);
      vt_entry.set(ID_access, ID_public);
      vt_entry.location() = symbol.location;
      virtual_table.components().push_back(vt_entry);

      // take care of overloading
      while(!virtual_bases.empty())
      {
        irep_idt virtual_base = *virtual_bases.begin();

        // a new function that does 'late casting' of the 'this' parameter
        symbolt func_symb;
        func_symb.name=component.get_name().as_string() + "::" +virtual_base.as_string();
        func_symb.base_name=component.get(ID_base_name);
        func_symb.pretty_name = component.get(ID_base_name);
        func_symb.mode=ID_cpp;
        func_symb.module=module;
        func_symb.location=component.location();
        func_symb.type=component.type();

        // change the type of the 'this' pointer
        code_typet& code_type = to_code_type(func_symb.type);
        code_typet::argumentt& arg= code_type.arguments().front();
        arg.type().subtype().set(ID_identifier, virtual_base);

        // create symbols for the arguments
        code_typet::argumentst& args =  code_type.arguments();
        for(unsigned i=0; i<args.size(); i++)
        {
          code_typet::argumentt& arg = args[i];
          irep_idt base_name = arg.get_base_name();

          if(base_name==irep_idt())
            base_name="arg"+i2string(i);

          symbolt arg_symb;
          arg_symb.name = func_symb.name.as_string() + "::"+ base_name.as_string();
          arg_symb.base_name = base_name;
          arg_symb.pretty_name = base_name;
          arg_symb.mode=ID_cpp;
          arg_symb.location=func_symb.location;
          arg_symb.type = arg.type();

          arg.set(ID_C_identifier, arg_symb.name);

          // add the argument to the symbol table
          bool failed = context.move(arg_symb);
          assert(!failed);
        }

        // do the body of the function
        typecast_exprt late_cast(to_code_type(component.type()).arguments()[0].type());

        late_cast.op0()=
          symbol_expr(namespacet(context).lookup(
            args[0].get(ID_C_identifier)));
        
        if(code_type.return_type().id()!=ID_empty &&
           code_type.return_type().id()!=ID_destructor)
        {
          side_effect_expr_function_callt expr_call;
          expr_call.function() = symbol_exprt(component.get_name(),component.type());
          expr_call.type() = to_code_type(component.type()).return_type();
          expr_call.arguments().reserve(args.size());
          expr_call.arguments().push_back(late_cast);

          for(unsigned i=1; i < args.size(); i++)
          {
            expr_call.arguments().push_back(
              symbol_expr(namespacet(context).lookup(
                args[i].get(ID_C_identifier))));
          }

          code_returnt code_return;
          code_return.return_value() = expr_call;

          func_symb.value = code_return;
        }
        else
        {
          code_function_callt code_func;
          code_func.function() = symbol_exprt(component.get_name(),component.type());
          code_func.arguments().reserve(args.size());
          code_func.arguments().push_back(late_cast);

          for(unsigned i=1; i < args.size(); i++)
          {
            code_func.arguments().push_back(
              symbol_expr(namespacet(context).lookup(
                args[i].get(ID_C_identifier))));
          }

          func_symb.value = code_func;
        }

        // add this new function to the list of components
        
        struct_typet::componentt new_compo = component;
        new_compo.type() = func_symb.type;
        new_compo.set_name(func_symb.name);
        components.push_back(new_compo);

        // add the function to the symbol table
        {
          bool failed = context.move(func_symb);
          assert(!failed);
        }

        // next base
        virtual_bases.erase(virtual_bases.begin());
      }
    }
  }
  
  if(is_static && !is_method) // static non-method member
  {
    // add as global variable to context
    symbolt static_symbol;
    static_symbol.mode=symbol.mode;
    static_symbol.name=identifier;
    static_symbol.type=component.type();
    static_symbol.base_name=component.get(ID_base_name);
    static_symbol.lvalue=true;
    static_symbol.static_lifetime=true;
    static_symbol.location=cpp_name.location();
    static_symbol.is_extern=true;
    
    // TODO: not sure about this: should be defined separately!
    dynamic_initializations.push_back(static_symbol.name);

    symbolt *new_symbol;
    if(context.move(static_symbol, new_symbol))
    {
      err_location(cpp_name.location());
	str << "redeclaration of static member `" 
	    << static_symbol.base_name.as_string()
	    << "'";
      throw 0;
    }

    if(value.is_not_nil())
    {
      if(cpp_is_pod(new_symbol->type))
      {
        new_symbol->value.swap(value);
        c_typecheck_baset::do_initializer(*new_symbol);

        // these are macros if they are PODs and come with a (constant) value
        if(new_symbol->type.get_bool(ID_C_constant))
        {
          simplify(new_symbol->value, *this);
          new_symbol->is_macro=true;
        }
      }
      else
      {
        symbol_exprt symexpr;
        symexpr.set_identifier(new_symbol->name);

        exprt::operandst ops;
        ops.push_back(value);
        codet defcode =
          cpp_constructor(locationt(), symexpr, ops);

        new_symbol->value.swap(defcode);
      }
    }
  }

  // array members must have fixed size
  check_fixed_size_array(component.type());

  put_compound_into_scope(component);

  components.push_back(component);
}