static int
can_convert_eh (tree to, tree from)
{
to = non_reference (to);
from = non_reference (from);
if (TYPE_PTR_P (to) && TYPE_PTR_P (from))
{
to = TREE_TYPE (to);
from = TREE_TYPE (from);
if (! at_least_as_qualified_p (to, from))
return 0;
if (VOID_TYPE_P (to))
return 1;
/* Else fall through. */
}
if (CLASS_TYPE_P (to) && CLASS_TYPE_P (from)
&& publicly_uniquely_derived_p (to, from))
return 1;
return 0;
}
tree
convert_to_reference (tree reftype, tree expr, int convtype,
int flags, tree decl)
{
tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype));
tree intype;
tree rval = NULL_TREE;
tree rval_as_conversion = NULL_TREE;
bool can_convert_intype_to_type;
if (TREE_CODE (type) == FUNCTION_TYPE
&& TREE_TYPE (expr) == unknown_type_node)
expr = instantiate_type (type, expr,
(flags & LOOKUP_COMPLAIN)
? tf_warning_or_error : tf_none);
if (expr == error_mark_node)
return error_mark_node;
intype = TREE_TYPE (expr);
gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE);
gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE);
intype = TYPE_MAIN_VARIANT (intype);
can_convert_intype_to_type = can_convert (type, intype);
if (!can_convert_intype_to_type
&& (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype)
&& ! (flags & LOOKUP_NO_CONVERSION))
{
/* Look for a user-defined conversion to lvalue that we can use. */
rval_as_conversion
= build_type_conversion (reftype, expr);
if (rval_as_conversion && rval_as_conversion != error_mark_node
&& real_lvalue_p (rval_as_conversion))
{
expr = rval_as_conversion;
rval_as_conversion = NULL_TREE;
intype = type;
can_convert_intype_to_type = 1;
}
}
if (((convtype & CONV_STATIC) && can_convert (intype, type))
|| ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type))
{
if (flags & LOOKUP_COMPLAIN)
{
tree ttl = TREE_TYPE (reftype);
tree ttr = lvalue_type (expr);
if (! real_lvalue_p (expr))
warn_ref_binding (reftype, intype, decl);
if (! (convtype & CONV_CONST)
&& !at_least_as_qualified_p (ttl, ttr))
permerror (input_location, "conversion from %qT to %qT discards qualifiers",
ttr, reftype);
}
return build_up_reference (reftype, expr, flags, decl);
}
else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr))
{
/* When casting an lvalue to a reference type, just convert into
a pointer to the new type and deference it. This is allowed
by San Diego WP section 5.2.9 paragraph 12, though perhaps it
should be done directly (jason). (int &)ri ---> *(int*)&ri */
/* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they
meant. */
if (TREE_CODE (intype) == POINTER_TYPE
&& (comptypes (TREE_TYPE (intype), type,
COMPARE_BASE | COMPARE_DERIVED)))
warning (0, "casting %qT to %qT does not dereference pointer",
intype, reftype);
rval = cp_build_unary_op (ADDR_EXPR, expr, 0, tf_warning_or_error);
if (rval != error_mark_node)
rval = convert_force (build_pointer_type (TREE_TYPE (reftype)),
rval, 0);
if (rval != error_mark_node)
rval = build1 (NOP_EXPR, reftype, rval);
}
else
{
rval = convert_for_initialization (NULL_TREE, type, expr, flags,
"converting", 0, 0,
tf_warning_or_error);
if (rval == NULL_TREE || rval == error_mark_node)
return rval;
warn_ref_binding (reftype, intype, decl);
rval = build_up_reference (reftype, rval, flags, decl);
}
if (rval)
{
/* If we found a way to convert earlier, then use it. */
return rval;
}
if (flags & LOOKUP_COMPLAIN)
error ("cannot convert type %qT to type %qT", intype, reftype);
return error_mark_node;
}
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;
}
