bool check_c_implicit_typecast(
const typet &src_type,
const typet &dest_type)
{
// check qualifiers
if(src_type.id()==ID_pointer && dest_type.id()==ID_pointer &&
src_type.subtype().get_bool(ID_C_constant) &&
!dest_type.subtype().get_bool(ID_C_constant))
return true;
if(src_type==dest_type) return false;
const irep_idt &src_type_id=src_type.id();
if(src_type_id==ID_natural)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_integer)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_real)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_rational)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_bool)
{
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_c_enum) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_unsignedbv ||
src_type_id==ID_signedbv ||
src_type_id==ID_c_enum ||
src_type_id==ID_incomplete_c_enum)
{
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_rational) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_c_enum) return false;
if(dest_type.id()==ID_incomplete_c_enum) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_floatbv ||
src_type_id==ID_fixedbv)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_rational) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_array ||
src_type_id==ID_pointer)
{
if(dest_type.id()==ID_pointer)
{
const irept &dest_subtype=dest_type.subtype();
const irept &src_subtype =src_type.subtype();
if(src_subtype==dest_subtype)
return false;
else if(is_void_pointer(src_type) || // from void to anything
is_void_pointer(dest_type)) // to void from anything
return false;
}
if(dest_type.id()==ID_array &&
src_type.subtype()==dest_type.subtype()) return false;
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
}
else if(src_type_id==ID_vector)
{
if(dest_type.id()==ID_vector)
return false;
}
else if(src_type_id==ID_complex)
{
if(dest_type.id()==ID_complex)
{
// We convert between complex types if we convert between
// their component types.
if(!check_c_implicit_typecast(src_type.subtype(), dest_type.subtype()))
return false;
}
}
return true;
}
void c_typecastt::implicit_typecast_followed(
exprt &expr,
const typet &src_type,
const typet &dest_type)
{
if(dest_type.id()==ID_union)
// do transparent union
if(dest_type.id()==ID_union &&
dest_type.get_bool(ID_C_transparent_union) &&
src_type.id()!=ID_union)
{
// The argument corresponding to a transparent union type can be of any
// type in the union; no explicit cast is required.
// Check union members.
const union_typet &dest_union_type=to_union_type(dest_type);
for(union_typet::componentst::const_iterator
it=dest_union_type.components().begin();
it!=dest_union_type.components().end();
it++)
{
if(!check_c_implicit_typecast(src_type, it->type()))
{
// build union constructor
exprt union_expr(ID_union, dest_union_type);
union_expr.move_to_operands(expr);
union_expr.set(ID_component_name, it->get_name());
expr=union_expr;
return; // ok
}
}
}
if(dest_type.id()==ID_pointer)
{
// special case: 0 == NULL
if(expr.is_zero() && (
src_type.id()==ID_unsignedbv ||
src_type.id()==ID_signedbv ||
src_type.id()==ID_natural ||
src_type.id()==ID_integer))
{
expr=exprt(ID_constant, dest_type);
expr.set(ID_value, ID_NULL);
return; // ok
}
if(src_type.id()==ID_pointer ||
src_type.id()==ID_array)
{
// we are quite generous about pointers
const typet &src_sub=ns.follow(src_type.subtype());
const typet &dest_sub=ns.follow(dest_type.subtype());
if(is_void_pointer(src_type) ||
is_void_pointer(dest_type))
{
// from/to void is always good
}
else if(src_sub.id()==ID_code &&
dest_sub.id()==ID_code)
{
// very generous:
// between any two function pointers it's ok
}
else if(base_type_eq(src_type.subtype(), dest_type.subtype(), ns))
{
// ok
}
else if((is_number(src_sub) || src_sub.id()==ID_c_enum) &&
(is_number(dest_sub) || dest_sub.id()==ID_c_enum))
{
// Also generous: between any to scalar types it's ok.
// We should probably check the size.
}
else
warnings.push_back("incompatible pointer types");
// check qualifiers
/*
if(src_type.subtype().get_bool(ID_C_constant) &&
!dest_type.subtype().get_bool(ID_C_constant))
warnings.push_back("disregarding const");
*/
if(src_type.subtype().get_bool(ID_C_volatile) &&
!dest_type.subtype().get_bool(ID_C_volatile))
warnings.push_back("disregarding volatile");
if(src_type==dest_type)
{
expr.type()=src_type; // because of qualifiers
}
else
do_typecast(expr, dest_type);
return; // ok
}
}
if(check_c_implicit_typecast(src_type, dest_type))
errors.push_back("implicit conversion not permitted");
else if(src_type!=dest_type)
do_typecast(expr, dest_type);
}
bool check_c_implicit_typecast(
const typet &src_type,
const typet &dest_type)
{
// check qualifiers
if(src_type.id()==ID_pointer && dest_type.id()==ID_pointer &&
src_type.subtype().get_bool(ID_C_constant) &&
!dest_type.subtype().get_bool(ID_C_constant))
return true;
if(src_type==dest_type) return false;
const irep_idt &src_type_id=src_type.id();
if(src_type_id==ID_c_bit_field)
return check_c_implicit_typecast(src_type.subtype(), dest_type);
if(dest_type.id()==ID_c_bit_field)
return check_c_implicit_typecast(src_type, dest_type.subtype());
if(src_type_id==ID_natural)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_integer)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_real)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_rational)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_complex) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_bool)
{
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_c_enum) return false;
if(dest_type.id()==ID_c_enum_tag) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_unsignedbv ||
src_type_id==ID_signedbv ||
src_type_id==ID_c_enum ||
src_type_id==ID_c_enum_tag ||
src_type_id==ID_incomplete_c_enum ||
src_type_id==ID_c_bool)
{
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_rational) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_pointer) return false;
if(dest_type.id()==ID_c_enum) return false;
if(dest_type.id()==ID_c_enum_tag) return false;
if(dest_type.id()==ID_incomplete_c_enum) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_floatbv ||
src_type_id==ID_fixedbv)
{
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_integer) return false;
if(dest_type.id()==ID_real) return false;
if(dest_type.id()==ID_rational) return false;
if(dest_type.id()==ID_signedbv) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_floatbv) return false;
if(dest_type.id()==ID_fixedbv) return false;
if(dest_type.id()==ID_complex) return false;
}
else if(src_type_id==ID_complex)
{
if(dest_type.id()==ID_complex)
return check_c_implicit_typecast(src_type.subtype(), dest_type.subtype());
else
{
// 6.3.1.7, par 2:
// When a value of complex type is converted to a real type, the
// imaginary part of the complex value is discarded and the value of the
// real part is converted according to the conversion rules for the
// corresponding real type.
return check_c_implicit_typecast(src_type.subtype(), dest_type);
}
}
else if(src_type_id==ID_array ||
src_type_id==ID_pointer)
{
if(dest_type.id()==ID_pointer)
{
const irept &dest_subtype=dest_type.subtype();
const irept &src_subtype =src_type.subtype();
if(src_subtype==dest_subtype)
return false;
else if(is_void_pointer(src_type) || // from void to anything
is_void_pointer(dest_type)) // to void from anything
return false;
}
if(dest_type.id()==ID_array &&
src_type.subtype()==dest_type.subtype()) return false;
if(dest_type.id()==ID_bool) return false;
if(dest_type.id()==ID_c_bool) return false;
if(dest_type.id()==ID_unsignedbv) return false;
if(dest_type.id()==ID_signedbv) return false;
}
else if(src_type_id==ID_vector)
{
if(dest_type.id()==ID_vector)
return false;
}
else if(src_type_id==ID_complex)
{
if(dest_type.id()==ID_complex)
{
// We convert between complex types if we convert between
// their component types.
if(!check_c_implicit_typecast(src_type.subtype(), dest_type.subtype()))
return false;
}
}
return true;
}
