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
cp_convert_to_pointer (tree type, tree expr)
{
tree intype = TREE_TYPE (expr);
enum tree_code form;
tree rval;
if (intype == error_mark_node)
return error_mark_node;
if (MAYBE_CLASS_TYPE_P (intype))
{
intype = complete_type (intype);
if (!COMPLETE_TYPE_P (intype))
{
error ("can't convert from incomplete type %qT to %qT",
intype, type);
return error_mark_node;
}
rval = build_type_conversion (type, expr);
if (rval)
{
if (rval == error_mark_node)
error ("conversion of %qE from %qT to %qT is ambiguous",
expr, intype, type);
return rval;
}
}
/* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
if (TREE_CODE (type) == POINTER_TYPE
&& (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
|| VOID_TYPE_P (TREE_TYPE (type))))
{
if (TYPE_PTRMEMFUNC_P (intype)
|| TREE_CODE (intype) == METHOD_TYPE)
return convert_member_func_to_ptr (type, expr);
if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
return build_nop (type, expr);
intype = TREE_TYPE (expr);
}
if (expr == error_mark_node)
return error_mark_node;
form = TREE_CODE (intype);
if (POINTER_TYPE_P (intype))
{
intype = TYPE_MAIN_VARIANT (intype);
if (TYPE_MAIN_VARIANT (type) != intype
&& TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
&& MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
&& MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
&& TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
{
enum tree_code code = PLUS_EXPR;
tree binfo;
tree intype_class;
tree type_class;
bool same_p;
intype_class = TREE_TYPE (intype);
type_class = TREE_TYPE (type);
same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
TYPE_MAIN_VARIANT (type_class));
binfo = NULL_TREE;
/* Try derived to base conversion. */
if (!same_p)
binfo = lookup_base (intype_class, type_class, ba_check, NULL);
if (!same_p && !binfo)
{
/* Try base to derived conversion. */
binfo = lookup_base (type_class, intype_class, ba_check, NULL);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (binfo || same_p)
{
if (binfo)
expr = build_base_path (code, expr, binfo, 0);
/* Add any qualifier conversions. */
return build_nop (type, expr);
}
}
if (TYPE_PTRMEMFUNC_P (type))
{
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
return build_nop (type, expr);
}
else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
|| (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
return convert_ptrmem (type, expr, /*allow_inverse_p=*/false,
/*c_cast_p=*/false);
else if (TYPE_PTRMEMFUNC_P (intype))
{
if (!warn_pmf2ptr)
{
if (TREE_CODE (expr) == PTRMEM_CST)
return cp_convert_to_pointer (type,
PTRMEM_CST_MEMBER (expr));
else if (TREE_CODE (expr) == OFFSET_REF)
{
tree object = TREE_OPERAND (expr, 0);
return get_member_function_from_ptrfunc (&object,
TREE_OPERAND (expr, 1));
}
}
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
if (integer_zerop (expr))
{
if (TYPE_PTRMEMFUNC_P (type))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
/*c_cast_p=*/false);
if (TYPE_PTRMEM_P (type))
{
/* A NULL pointer-to-member is represented by -1, not by
zero. */
expr = build_int_cst_type (type, -1);
}
else
expr = build_int_cst (type, 0);
return expr;
}
else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
{
error ("invalid conversion from %qT to %qT", intype, type);
return error_mark_node;
}
if (INTEGRAL_CODE_P (form))
{
if (TYPE_PRECISION (intype) == POINTER_SIZE)
return build1 (CONVERT_EXPR, type, expr);
expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
/* Modes may be different but sizes should be the same. There
is supposed to be some integral type that is the same width
as a pointer. */
gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
== GET_MODE_SIZE (TYPE_MODE (type)));
return convert_to_pointer (type, expr);
}
if (type_unknown_p (expr))
return instantiate_type (type, expr, tf_warning_or_error);
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
static tree
cp_convert_to_pointer (tree type, tree expr, bool force)
{
tree intype = TREE_TYPE (expr);
enum tree_code form;
tree rval;
if (intype == error_mark_node)
return error_mark_node;
if (IS_AGGR_TYPE (intype))
{
intype = complete_type (intype);
if (!COMPLETE_TYPE_P (intype))
{
error ("can't convert from incomplete type `%T' to `%T'",
intype, type);
return error_mark_node;
}
rval = build_type_conversion (type, expr);
if (rval)
{
if (rval == error_mark_node)
error ("conversion of `%E' from `%T' to `%T' is ambiguous",
expr, intype, type);
return rval;
}
}
/* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
if (TREE_CODE (type) == POINTER_TYPE
&& (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
|| VOID_TYPE_P (TREE_TYPE (type))))
{
/* Allow an implicit this pointer for pointer to member
functions. */
if (TYPE_PTRMEMFUNC_P (intype))
{
if (pedantic || warn_pmf2ptr)
pedwarn ("converting from `%T' to `%T'", intype, type);
if (TREE_CODE (expr) == PTRMEM_CST)
expr = build_address (PTRMEM_CST_MEMBER (expr));
else
{
tree decl = maybe_dummy_object (TYPE_PTRMEM_CLASS_TYPE (intype),
0);
decl = build_address (decl);
expr = get_member_function_from_ptrfunc (&decl, expr);
}
}
else if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE)
{
if (pedantic || warn_pmf2ptr)
pedwarn ("converting from `%T' to `%T'", intype, type);
expr = build_addr_func (expr);
}
if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
return build_nop (type, expr);
intype = TREE_TYPE (expr);
}
if (expr == error_mark_node)
return error_mark_node;
form = TREE_CODE (intype);
if (POINTER_TYPE_P (intype))
{
intype = TYPE_MAIN_VARIANT (intype);
if (TYPE_MAIN_VARIANT (type) != intype
&& TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
&& IS_AGGR_TYPE (TREE_TYPE (type))
&& IS_AGGR_TYPE (TREE_TYPE (intype))
&& TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
{
enum tree_code code = PLUS_EXPR;
tree binfo;
tree intype_class;
tree type_class;
bool same_p;
intype_class = TREE_TYPE (intype);
type_class = TREE_TYPE (type);
same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
TYPE_MAIN_VARIANT (type_class));
binfo = NULL_TREE;
/* Try derived to base conversion. */
if (!same_p)
binfo = lookup_base (intype_class, type_class, ba_check, NULL);
if (!same_p && !binfo)
{
/* Try base to derived conversion. */
binfo = lookup_base (type_class, intype_class, ba_check, NULL);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (binfo || same_p)
{
if (binfo)
expr = build_base_path (code, expr, binfo, 0);
/* Add any qualifier conversions. */
return build_nop (type, expr);
}
}
if (TYPE_PTRMEMFUNC_P (type))
{
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
return build_nop (type, expr);
}
else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
{
tree b1;
tree b2;
tree binfo;
enum tree_code code = PLUS_EXPR;
base_kind bk;
b1 = TYPE_PTRMEM_CLASS_TYPE (type);
b2 = TYPE_PTRMEM_CLASS_TYPE (intype);
binfo = lookup_base (b1, b2, ba_check, &bk);
if (!binfo)
{
binfo = lookup_base (b2, b1, ba_check, &bk);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (bk == bk_via_virtual)
{
if (force)
warning ("pointer to member cast from `%T' to `%T' is via virtual base",
intype, type);
else
{
error ("pointer to member cast from `%T' to `%T' is via virtual base",
intype, type);
return error_mark_node;
}
/* This is a reinterpret cast, whose result is unspecified.
We choose to do nothing. */
return build1 (NOP_EXPR, type, expr);
}
if (TREE_CODE (expr) == PTRMEM_CST)
expr = cplus_expand_constant (expr);
if (binfo && !integer_zerop (BINFO_OFFSET (binfo)))
expr = size_binop (code,
build_nop (sizetype, expr),
BINFO_OFFSET (binfo));
return build_nop (type, expr);
}
else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0);
else if (TYPE_PTRMEMFUNC_P (intype))
{
if (!warn_pmf2ptr)
{
if (TREE_CODE (expr) == PTRMEM_CST)
return cp_convert_to_pointer (type,
PTRMEM_CST_MEMBER (expr),
force);
else if (TREE_CODE (expr) == OFFSET_REF)
{
tree object = TREE_OPERAND (expr, 0);
return get_member_function_from_ptrfunc (&object,
TREE_OPERAND (expr, 1));
}
}
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
if (integer_zerop (expr))
{
if (TYPE_PTRMEMFUNC_P (type))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0);
if (TYPE_PTRMEM_P (type))
/* A NULL pointer-to-member is represented by -1, not by
zero. */
expr = build_int_2 (-1, -1);
else
expr = build_int_2 (0, 0);
TREE_TYPE (expr) = type;
/* Fix up the representation of -1 if appropriate. */
force_fit_type (expr, 0);
return expr;
}
else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
{
error ("invalid conversion from '%T' to '%T'", intype, type);
return error_mark_node;
}
if (INTEGRAL_CODE_P (form))
{
if (TYPE_PRECISION (intype) == POINTER_SIZE)
return build1 (CONVERT_EXPR, type, expr);
expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
/* Modes may be different but sizes should be the same. */
if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
!= GET_MODE_SIZE (TYPE_MODE (type)))
/* There is supposed to be some integral type
that is the same width as a pointer. */
abort ();
return convert_to_pointer (type, expr);
}
if (type_unknown_p (expr))
return instantiate_type (type, expr, tf_error | tf_warning);
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
