void check_return(expression e)
{
type ret = current_return_type();
if (type_void(ret))
{
if (pedantic || !type_void(e->type))
warning("`return' with a value, in function returning void");
}
else
{
check_assignment(ret, default_conversion_for_assignment(e), e, "return", NULL, NULL, 0);
/* XXX: Missing warning about returning address of local var */
}
}
static void check_dereference(expression result, type dereferenced,
const char *errorstring)
{
if (type_pointer(dereferenced))
{
type t = type_points_to(dereferenced);
result->type = t;
#if 0
if (TYPE_SIZE (t) == 0 && TREE_CODE (t) != ARRAY_TYPE)
{
error ("dereferencing pointer to incomplete type");
return error_mark_node;
}
#endif
if (type_void(t) && unevaluated_expression == 0)
warning("dereferencing `void *' pointer");
result->side_effects |= type_volatile(t) || flag_volatile;
}
else
{
result->type = error_type;
if (dereferenced != error_type)
error("invalid type argument of `%s'", errorstring);
}
result->lvalue = TRUE;
}
void check_void_return(void)
{
type ret = current_return_type();
if (warn_return_type && ret != error_type && !type_void(ret))
warning("`return' with no value, in function returning non-void");
}
static void incomplete_type_error(expression e, type t)
{
/* Avoid duplicate error message. */
if (t == error_type)
return;
if (e && is_identifier(e))
error("`%s' has an incomplete type", CAST(identifier, e)->cstring.data);
else
{
while (type_array(t) && type_array_size(t))
t = type_array_of(t);
if (type_struct(t))
error("invalid use of undefined type `struct %s'", type_tag(t)->name);
else if (type_union(t))
error("invalid use of undefined type `union %s'", type_tag(t)->name);
else if (type_enum(t))
error("invalid use of undefined type `enum %s'", type_tag(t)->name);
else if (type_void(t))
error("invalid use of void expression");
else if (type_array(t))
error("invalid use of array with unspecified bounds");
else
assert(0);
/* XXX: Missing special message for typedef's */
}
}
value type_num(value f)
{
if (f->N == 0)
{
num_free(get_num(f));
return 0;
}
return type_void(f);
}
value type_var(value f)
{
if (f->N == 0)
{
drop(get_var(f));
return 0;
}
return type_void(f);
}
static void ptrconversion_warnings(type ttl, type ttr, expression rhs,
const char *context,
const char *funname, int parmnum,
bool pedantic)
{
if (pedantic
&& ((type_void(ttl) && type_function(ttr)) ||
(type_function(ttl) && type_void(ttr) &&
!(rhs && definite_null(rhs)))))
warn_for_assignment("ANSI forbids %s between function pointer and `void *'",
context, funname, parmnum);
/* Const and volatile mean something different for function
types, so the usual warnings are not appropriate. */
else if (type_function(ttl) && type_function(ttr))
{
/* Because const and volatile on functions are
restrictions that say the function will not do
certain things, it is okay to use a const or volatile
function where an ordinary one is wanted, but not
vice-versa. */
if (type_const(ttl) && !type_const(ttr))
warn_for_assignment("%s makes `const *' function pointer from non-const",
context, funname, parmnum);
if (type_volatile(ttl) && !type_volatile(ttr))
warn_for_assignment("%s makes `volatile *' function pointer from non-volatile",
context, funname, parmnum);
}
else if (!type_function(ttl) && !type_function(ttr))
{
if (!type_const(ttl) && type_const(ttr))
warn_for_assignment("%s discards `const' from pointer target type",
context, funname, parmnum);
if (!type_volatile(ttl) && type_volatile(ttr))
warn_for_assignment("%s discards `volatile' from pointer target type",
context, funname, parmnum);
/* If this is not a case of ignoring a mismatch in signedness,
no warning. */
if (!assignable_pointer_targets(ttl, ttr, FALSE) && pedantic)
warn_for_assignment("pointer targets in %s differ in signedness",
context, funname, parmnum);
}
}
bool valid_compare(type t1, type t2, expression e1)
{
if (type_void(type_points_to(t1)))
{
if (pedantic && type_function(type_points_to(t2)) && !definite_null(e1))
pedwarn("ANSI C forbids comparison of `void *' with function pointer");
return TRUE;
}
return FALSE;
}
static bool voidstar_conditional(type t1, type t2)
{
if (type_void(t1))
{
if (pedantic && type_function(t2))
pedwarn("ANSI C forbids conditional expr between `void *' and function pointer");
return TRUE;
}
return FALSE;
}
type default_conversion(expression e)
{
type from = e->type;
if (type_enum(from))
from = type_tag(from)->reptype;
if (type_smallerthanint(from))
{
/* Traditionally, unsignedness is preserved in default promotions. */
if (flag_traditional && type_unsigned(from))
return unsigned_int_type;
else
return int_type;
}
if (flag_traditional && !flag_allow_single_precision && type_float(from))
return double_type;
if (type_void(from))
{
error("void value not ignored as it ought to be");
return error_type;
}
if (type_function(from))
{
assert(!e->cst);
e->cst = e->static_address;
return make_pointer_type(from);
}
if (type_array(from))
{
if (!e->lvalue)
{
error("invalid use of non-lvalue array");
return error_type;
}
assert(!e->cst);
e->cst = e->static_address;
/* It's being used as a pointer, so is not an lvalue */
e->lvalue = FALSE;
return make_pointer_type(type_array_of(from));
}
return from;
}
void check_sizeof(expression result, type stype)
{
if (type_function(stype))
{
if (pedantic || warn_pointer_arith)
pedwarn("sizeof applied to a function type");
}
else if (type_void(stype))
{
if (pedantic || warn_pointer_arith)
pedwarn("sizeof applied to a void type");
}
else if (type_incomplete(stype))
error("sizeof applied to an incomplete type");
result->type = size_t_type;
result->cst = fold_sizeof(result, stype);
}
type pointer_int_sum(type ptype, type itype)
{
type pointed = type_points_to(ptype);
if (type_void(pointed))
{
if (pedantic || warn_pointer_arith)
pedwarn("pointer of type `void *' used in arithmetic");
}
else if (type_function(pointed))
{
if (pedantic || warn_pointer_arith)
pedwarn("pointer to a function used in arithmetic");
}
else if (type_incomplete(pointed))
error("arithmetic on pointer to an incomplete type");
return ptype;
}
value type_file(value f)
{
if (f->N == 0)
return 0;
return type_void(f);
}
expression make_cast(location loc, asttype t, expression e)
{
expression result = CAST(expression, new_cast(parse_region, loc, e, t));
type castto = t->type;
if (castto == error_type || type_void(castto))
; /* Do nothing */
else if (type_array(castto))
{
error("cast specifies array type");
castto = error_type;
}
else if (type_function(castto))
{
error("cast specifies function type");
castto = error_type;
}
else if (type_equal_unqualified(castto, e->type))
{
if (pedantic && type_aggregate(castto))
pedwarn("ANSI C forbids casting nonscalar to the same type");
}
else
{
type etype = e->type;
/* Convert functions and arrays to pointers,
but don't convert any other types. */
if (type_function(etype) || type_array(etype))
etype = default_conversion(e);
if (type_union(castto))
{
tag_declaration utag = type_tag(castto);
field_declaration ufield;
/* Look for etype as a field of the union */
for (ufield = utag->fieldlist; ufield; ufield = ufield->next)
if (ufield->name && type_equal_unqualified(ufield->type, etype))
{
if (pedantic)
pedwarn("ANSI C forbids casts to union type");
break;
}
if (!ufield)
error("cast to union type from type not present in union");
}
else
{
/* Optionally warn about potentially worrisome casts. */
if (warn_cast_qual && type_pointer(etype) && type_pointer(castto))
{
type ep = type_points_to(etype), cp = type_points_to(castto);
if (type_volatile(ep) && !type_volatile(cp))
pedwarn("cast discards `volatile' from pointer target type");
if (type_const(ep) && !type_const(cp))
pedwarn("cast discards `const' from pointer target type");
}
/* This warning is weird */
if (warn_bad_function_cast && is_function_call(e) &&
!type_equal_unqualified(castto, etype))
warning ("cast does not match function type");
#if 0
/* Warn about possible alignment problems. */
if (STRICT_ALIGNMENT && warn_cast_align
&& TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (otype) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
&& TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
/* Don't warn about opaque types, where the actual alignment
restriction is unknown. */
&& !((TREE_CODE (TREE_TYPE (otype)) == UNION_TYPE
|| TREE_CODE (TREE_TYPE (otype)) == RECORD_TYPE)
&& TYPE_MODE (TREE_TYPE (otype)) == VOIDmode)
&& TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
warning ("cast increases required alignment of target type");
if (TREE_CODE (type) == INTEGER_TYPE
&& TREE_CODE (otype) == POINTER_TYPE
&& TYPE_PRECISION (type) != TYPE_PRECISION (otype)
&& !TREE_CONSTANT (value))
warning ("cast from pointer to integer of different size");
if (TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (otype) == INTEGER_TYPE
&& TYPE_PRECISION (type) != TYPE_PRECISION (otype)
#if 0
/* Don't warn about converting 0 to pointer,
provided the 0 was explicit--not cast or made by folding. */
&& !(TREE_CODE (value) == INTEGER_CST && integer_zerop (value))
#endif
/* Don't warn about converting any constant. */
&& !TREE_CONSTANT (value))
warning ("cast to pointer from integer of different size");
#endif
check_conversion(castto, etype);
}
}
result->lvalue = !pedantic && e->lvalue;
result->isregister = e->isregister;
result->bitfield = e->bitfield;
result->static_address = e->static_address;
result->type = castto;
result->cst = fold_cast(result);
return result;
}
/* Return TRUE if no error and lhstype and rhstype are not error_type */
bool check_assignment(type lhstype, type rhstype, expression rhs,
const char *context, data_declaration fundecl,
const char *funname, int parmnum)
{
bool zerorhs = rhs && definite_zero(rhs);
if (lhstype == error_type || rhstype == error_type)
return FALSE;
if (type_void(rhstype))
{
error("void value not ignored as it ought to be");
return FALSE;
}
if (type_equal_unqualified(lhstype, rhstype))
return TRUE;
if (type_arithmetic(lhstype) && type_arithmetic(rhstype))
{
if (rhs)
constant_overflow_warning(rhs->cst);
return check_conversion(lhstype, rhstype);
}
if (parmnum && (type_qualifiers(lhstype) & transparent_qualifier))
{
/* See if we can match any field of lhstype */
tag_declaration tag = type_tag(lhstype);
field_declaration fields, marginal_field = NULL;
/* I blame gcc for this horrible mess (and it's minor inconsistencies
with the regular rules) */
/* pedantic warnings are skipped in here because we're already
issuing a warning for the use of this construct */
for (fields = tag->fieldlist; fields; fields = fields->next)
{
type ft = fields->type;
if (type_compatible(ft, rhstype))
break;
if (!type_pointer(ft))
continue;
if (type_pointer(rhstype))
{
type ttl = type_points_to(ft), ttr = type_points_to(rhstype);
bool goodmatch = assignable_pointer_targets(ttl, ttr, FALSE);
/* Any non-function converts to a [const][volatile] void *
and vice versa; otherwise, targets must be the same.
Meanwhile, the lhs target must have all the qualifiers of
the rhs. */
if (goodmatch)
{
/* If this type won't generate any warnings, use it. */
if ((type_function(ttr) && type_function(ttl))
? (((!type_const(ttl)) | type_const(ttr))
& ((!type_volatile(ttl)) | type_volatile(ttr)))
: (((type_const(ttl)) | (!type_const(ttr)))
& (type_volatile(ttl) | (!type_volatile(ttr)))))
break;
/* Keep looking for a better type, but remember this one. */
if (!marginal_field)
marginal_field = fields;
}
}
/* Can convert integer zero to any pointer type. */
/* Note that this allows passing *any* null pointer (gcc bug?) */
if (zerorhs)
break;
}
if (fields || marginal_field)
{
if (!fields)
{
/* We have only a marginally acceptable member type;
it needs a warning. */
type ttl = type_points_to(marginal_field->type),
ttr = type_points_to(rhstype);
ptrconversion_warnings(ttl, ttr, rhs, context, funname, parmnum,
FALSE);
}
if (pedantic && !(fundecl && fundecl->in_system_header))
pedwarn("ANSI C prohibits argument conversion to union type");
return TRUE;
}
}
if (type_pointer(lhstype) && type_pointer(rhstype))
{
type ttl = type_points_to(lhstype), ttr = type_points_to(rhstype);
bool goodmatch = assignable_pointer_targets(ttl, ttr, pedantic);
/* Any non-function converts to a [const][volatile] void *
and vice versa; otherwise, targets must be the same.
Meanwhile, the lhs target must have all the qualifiers of the rhs. */
if (goodmatch || (type_equal_unqualified(make_unsigned_type(ttl),
make_unsigned_type(ttr))))
ptrconversion_warnings(ttl, ttr, rhs, context, funname, parmnum,
pedantic);
else
warn_for_assignment("%s from incompatible pointer type",
context, funname, parmnum);
return check_conversion(lhstype, rhstype);
}
/* enum = ptr and ptr = enum counts as an error, so use type_integral */
else if (type_pointer(lhstype) && type_integral(rhstype))
{
if (!zerorhs)
warn_for_assignment("%s makes pointer from integer without a cast",
context, funname, parmnum);
return check_conversion(lhstype, rhstype);
}
else if (type_integral(lhstype) && type_pointer(rhstype))
{
warn_for_assignment("%s makes integer from pointer without a cast",
context, funname, parmnum);
return check_conversion(lhstype, rhstype);
}
if (!context)
if (funname)
error("incompatible type for argument %d of `%s'", parmnum, funname);
else
error("incompatible type for argument %d of indirect function call",
parmnum);
else
error("incompatible types in %s", context);
return FALSE;
}
static bool assignable_pointer_targets(type tt1, type tt2, bool pedantic)
{
return type_void(tt1) || type_void(tt2)
|| compatible_pointer_targets(tt1, tt2, pedantic);
}
bool check_conversion(type to, type from)
{
if (type_equal_unqualified(to, from))
return TRUE;
if (to == error_type || from == error_type)
return FALSE;
if (type_void(from))
{
error("void value not ignored as it ought to be");
return FALSE;
}
if (type_void(to))
return TRUE;
if (type_integer(to))
{
if (!type_scalar(from))
{
error("aggregate value used where an integer was expected");
return FALSE;
}
}
else if (type_pointer(to))
{
if (!(type_integer(from) || type_pointer(from)))
{
error("cannot convert to a pointer type");
return FALSE;
}
}
else if (type_floating(to))
{
if (type_pointer(from))
{
error("pointer value used where a floating point value was expected");
return FALSE;
}
else if (!type_arithmetic(from))
{
error("aggregate value used where a float was expected");
return FALSE;
}
}
else if (type_complex(to))
{
if (type_pointer(from))
{
error("pointer value used where a complex was expected");
return FALSE;
}
else if (!type_arithmetic(from))
{
error("aggregate value used where a complex was expected");
return FALSE;
}
}
else
{
error("conversion to non-scalar type requested");
return FALSE;
}
return TRUE;
}
