예제 #1
0
파일: cvt.c 프로젝트: h4ck3rm1k3/gcc
tree
convert_force (tree type, tree expr, int convtype)
{
  tree e = expr;
  enum tree_code code = TREE_CODE (type);

  if (code == REFERENCE_TYPE)
    return (fold_if_not_in_template
	    (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN,
				   NULL_TREE)));

  if (code == POINTER_TYPE)
    return fold_if_not_in_template (convert_to_pointer_force (type, e));

  /* From typeck.c convert_for_assignment */
  if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR
	&& TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE
	&& TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE)
       || integer_zerop (e)
       || TYPE_PTRMEMFUNC_P (TREE_TYPE (e)))
      && TYPE_PTRMEMFUNC_P (type))
    /* compatible pointer to member functions.  */
    return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1,
			     /*c_cast_p=*/1);

  return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL);
}
예제 #2
0
파일: cvt.c 프로젝트: Fokycnuk/gcc
tree
convert_lvalue (tree totype, tree expr)
{
  totype = cp_build_qualified_type (totype, TYPE_QUALS (TREE_TYPE (expr)));
  totype = build_reference_type (totype);
  expr = convert_to_reference (totype, expr, CONV_IMPLICIT, LOOKUP_NORMAL,
			       NULL_TREE);
  return convert_from_reference (expr);
}
예제 #3
0
파일: rtti.c 프로젝트: DJHartley/iphone-dev
static tree
build_dynamic_cast_1 (tree type, tree expr)
{
  enum tree_code tc = TREE_CODE (type);
  tree exprtype = TREE_TYPE (expr);
  tree dcast_fn;
  tree old_expr = expr;
  const char *errstr = NULL;

  /* T shall be a pointer or reference to a complete class type, or
     `pointer to cv void''.  */
  switch (tc)
    {
    case POINTER_TYPE:
      if (TREE_CODE (TREE_TYPE (type)) == VOID_TYPE)
	break;
      /* Fall through.  */
    case REFERENCE_TYPE:
      if (! IS_AGGR_TYPE (TREE_TYPE (type)))
	{
	  errstr = "target is not pointer or reference to class";
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (type))))
	{
	  errstr = "target is not pointer or reference to complete type";
	  goto fail;
	}
      break;

    default:
      errstr = "target is not pointer or reference";
      goto fail;
    }

  if (tc == POINTER_TYPE)
    {
      /* If T is a pointer type, v shall be an rvalue of a pointer to
	 complete class type, and the result is an rvalue of type T.  */

      if (TREE_CODE (exprtype) != POINTER_TYPE)
	{
	  errstr = "source is not a pointer";
	  goto fail;
	}
      if (! IS_AGGR_TYPE (TREE_TYPE (exprtype)))
	{
	  errstr = "source is not a pointer to class";
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
	{
	  errstr = "source is a pointer to incomplete type";
	  goto fail;
	}
    }
  else
    {
      /* Apply trivial conversion T -> T& for dereferenced ptrs.  */
      exprtype = build_reference_type (exprtype);
      expr = convert_to_reference (exprtype, expr, CONV_IMPLICIT,
				   LOOKUP_NORMAL, NULL_TREE);

      /* T is a reference type, v shall be an lvalue of a complete class
	 type, and the result is an lvalue of the type referred to by T.  */

      if (! IS_AGGR_TYPE (TREE_TYPE (exprtype)))
	{
	  errstr = "source is not of class type";
	  goto fail;
	}
      if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (exprtype))))
	{
	  errstr = "source is of incomplete class type";
	  goto fail;
	}
      
    }

  /* The dynamic_cast operator shall not cast away constness.  */
  if (!at_least_as_qualified_p (TREE_TYPE (type),
				TREE_TYPE (exprtype)))
    {
      errstr = "conversion casts away constness";
      goto fail;
    }

  /* If *type is an unambiguous accessible base class of *exprtype,
     convert statically.  */
  {
    tree binfo;

    binfo = lookup_base (TREE_TYPE (exprtype), TREE_TYPE (type),
			 ba_check, NULL);

    if (binfo)
      {
	expr = build_base_path (PLUS_EXPR, convert_from_reference (expr),
				binfo, 0);
	if (TREE_CODE (exprtype) == POINTER_TYPE)
	  expr = non_lvalue (expr);
	return expr;
      }
  }

  /* Otherwise *exprtype must be a polymorphic class (have a vtbl).  */
  if (TYPE_POLYMORPHIC_P (TREE_TYPE (exprtype)))
    {
      tree expr1;
      /* if TYPE is `void *', return pointer to complete object.  */
      if (tc == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (type)))
	{
	  /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b.  */
	  if (TREE_CODE (expr) == ADDR_EXPR
	      && TREE_CODE (TREE_OPERAND (expr, 0)) == VAR_DECL
	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
	    return build1 (NOP_EXPR, type, expr);

	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = build_headof (expr);
	  if (TREE_TYPE (expr1) != type)
	    expr1 = build1 (NOP_EXPR, type, expr1);
	  return ifnonnull (expr, expr1);
	}
      else
	{
	  tree retval;
          tree result, td2, td3, elems;
          tree static_type, target_type, boff;

 	  /* If we got here, we can't convert statically.  Therefore,
	     dynamic_cast<D&>(b) (b an object) cannot succeed.  */
	  if (tc == REFERENCE_TYPE)
	    {
	      if (TREE_CODE (old_expr) == VAR_DECL
		  && TREE_CODE (TREE_TYPE (old_expr)) == RECORD_TYPE)
		{
	          tree expr = throw_bad_cast ();
		  warning ("dynamic_cast of %q#D to %q#T can never succeed",
                           old_expr, type);
	          /* Bash it to the expected type.  */
	          TREE_TYPE (expr) = type;
		  return expr;
		}
	    }
	  /* Ditto for dynamic_cast<D*>(&b).  */
	  else if (TREE_CODE (expr) == ADDR_EXPR)
	    {
	      tree op = TREE_OPERAND (expr, 0);
	      if (TREE_CODE (op) == VAR_DECL
		  && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
		{
		  warning ("dynamic_cast of %q#D to %q#T can never succeed",
                           op, type);
		  retval = build_int_cst (type, 0); 
		  return retval;
		}
	    }

	  target_type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
	  static_type = TYPE_MAIN_VARIANT (TREE_TYPE (exprtype));
	  td2 = get_tinfo_decl (target_type);
	  mark_used (td2);
	  td2 = build_unary_op (ADDR_EXPR, td2, 0);
	  td3 = get_tinfo_decl (static_type);
	  mark_used (td3);
	  td3 = build_unary_op (ADDR_EXPR, td3, 0);

          /* Determine how T and V are related.  */
          boff = dcast_base_hint (static_type, target_type);
          
	  /* Since expr is used twice below, save it.  */
	  expr = save_expr (expr);

	  expr1 = expr;
	  if (tc == REFERENCE_TYPE)
	    expr1 = build_unary_op (ADDR_EXPR, expr1, 0);

	  elems = tree_cons
	    (NULL_TREE, expr1, tree_cons
	     (NULL_TREE, td3, tree_cons
	      (NULL_TREE, td2, tree_cons
	       (NULL_TREE, boff, NULL_TREE))));

	  dcast_fn = dynamic_cast_node;
	  if (!dcast_fn)
	    {
	      tree tmp;
	      tree tinfo_ptr;
	      tree ns = abi_node;
	      const char *name;
	      
	      push_nested_namespace (ns);
	      tinfo_ptr = xref_tag (class_type,
				    get_identifier ("__class_type_info"),
				    /* APPLE LOCAL 4184203 */
				    /*tag_scope=*/ts_global, false);
	      
	      tinfo_ptr = build_pointer_type
		(build_qualified_type
		 (tinfo_ptr, TYPE_QUAL_CONST));
	      name = "__dynamic_cast";
	      tmp = tree_cons
		(NULL_TREE, const_ptr_type_node, tree_cons
		 (NULL_TREE, tinfo_ptr, tree_cons
		  (NULL_TREE, tinfo_ptr, tree_cons
		   (NULL_TREE, ptrdiff_type_node, void_list_node))));
	      tmp = build_function_type (ptr_type_node, tmp);
	      dcast_fn = build_library_fn_ptr (name, tmp);
	      DECL_IS_PURE (dcast_fn) = 1;
              pop_nested_namespace (ns);
              dynamic_cast_node = dcast_fn;
	    }
          result = build_cxx_call (dcast_fn, elems);

	  if (tc == REFERENCE_TYPE)
	    {
	      tree bad = throw_bad_cast ();
	      
	      result = save_expr (result);
	      return build3 (COND_EXPR, type, result, result, bad);
	    }

	  /* Now back to the type we want from a void*.  */
	  result = cp_convert (type, result);
          return ifnonnull (expr, result);
	}
    }
  else
    errstr = "source type is not polymorphic";

 fail:
  error ("cannot dynamic_cast %qE (of type %q#T) to type %q#T (%s)",
         expr, exprtype, type, errstr);
  return error_mark_node;
}