/*
* Check, if the value of a node cannot represent a NULL pointer.
*
* - Sels are skipped
* - A SymConst(entity) is NEVER a NULL pointer
* - Confirms are evaluated
*/
int value_not_null(const ir_node *n, const ir_node **confirm)
{
ir_tarval *tv;
*confirm = NULL;
tv = value_of(n);
if (tarval_is_constant(tv) && ! tarval_is_null(tv))
return 1;
assert(mode_is_reference(get_irn_mode(n)));
/* skip all Sel nodes */
while (is_Sel(n)) {
n = get_Sel_ptr(n);
}
while (1) {
if (is_Proj(n)) { n = get_Proj_pred(n); continue; }
break;
}
if (is_SymConst_addr_ent(n)) {
/* global references are never NULL */
return 1;
} else if (n == get_irg_frame(get_irn_irg(n))) {
/* local references are never NULL */
return 1;
} else if (is_Alloc(n)) {
/* alloc never returns NULL (it throws an exception instead) */
return 1;
} else {
/* check for more Confirms */
for (; is_Confirm(n); n = get_Confirm_value(n)) {
if (get_Confirm_relation(n) == ir_relation_less_greater) {
ir_node *bound = get_Confirm_bound(n);
ir_tarval *tv = value_of(bound);
if (tarval_is_null(tv)) {
*confirm = n;
return 1;
}
}
}
}
return 0;
}
/*
* Transform Sel[method] to SymC[method] if possible.
* (see opt_polymorphy in libfirm)
*/
static ir_node *transform_node_Sel2(ir_node *node)
{
ir_node *new_node;
ir_entity *ent = get_Sel_entity(node);
if (get_irp_phase_state() == phase_building) return node;
if (!get_opt_dyn_meth_dispatch())
return node;
if (!is_Method_type(get_entity_type(ent)))
return node;
ddispatch_binding bind = oo_get_entity_binding(ent);
assert (bind != bind_unknown);
if (bind == bind_static)
return node;
/* If we know the dynamic type, we can replace the Sel by a constant. */
ir_node *ptr = get_Sel_ptr(node); /* The address we select from. */
ir_type *dyn_tp = get_irn_typeinfo_type(ptr);
if (dyn_tp != initial_type) {
ir_entity *called_ent;
/* We know which method will be called, no dispatch necessary. */
called_ent = resolve_ent_polymorphy(dyn_tp, ent);
assert (! oo_get_method_is_abstract(called_ent));
assert (! oo_get_class_is_interface(get_entity_owner(called_ent)));
new_node = copy_const_value(get_irn_dbg_info(node), get_atomic_ent_value(called_ent), get_nodes_block(node));
return new_node;
}
return node;
}
/**
* Lower a Sel node. Do not touch Sels accessing entities on the frame type.
*/
static void lower_sel(ir_node *sel)
{
ir_graph *irg = get_irn_irg(sel);
ir_entity *ent = get_Sel_entity(sel);
ir_type *owner = get_entity_owner(ent);
dbg_info *dbg = get_irn_dbg_info(sel);
ir_mode *mode = get_irn_mode(sel);
ir_node *bl = get_nodes_block(sel);
ir_node *newn;
/* we can only replace Sels when the layout of the owner type is decided. */
if (get_type_state(owner) != layout_fixed)
return;
if (0 < get_Sel_n_indexs(sel)) {
/* an Array access */
ir_type *basetyp = get_entity_type(ent);
ir_mode *basemode;
ir_node *index;
if (is_Primitive_type(basetyp))
basemode = get_type_mode(basetyp);
else
basemode = mode_P_data;
assert(basemode && "no mode for lowering Sel");
assert((get_mode_size_bits(basemode) % 8 == 0) && "can not deal with unorthodox modes");
index = get_Sel_index(sel, 0);
if (is_Array_type(owner)) {
ir_type *arr_ty = owner;
size_t dims = get_array_n_dimensions(arr_ty);
size_t *map = ALLOCAN(size_t, dims);
ir_mode *mode_Int = get_reference_mode_signed_eq(mode);
ir_tarval *tv;
ir_node *last_size;
size_t i;
assert(dims == (size_t)get_Sel_n_indexs(sel)
&& "array dimension must match number of indices of Sel node");
for (i = 0; i < dims; i++) {
size_t order = get_array_order(arr_ty, i);
assert(order < dims &&
"order of a dimension must be smaller than the arrays dim");
map[order] = i;
}
newn = get_Sel_ptr(sel);
/* Size of the array element */
tv = new_tarval_from_long(get_type_size_bytes(basetyp), mode_Int);
last_size = new_rd_Const(dbg, irg, tv);
/*
* We compute the offset part of dimension d_i recursively
* with the the offset part of dimension d_{i-1}
*
* off_0 = sizeof(array_element_type);
* off_i = (u_i - l_i) * off_{i-1} ; i >= 1
*
* whereas u_i is the upper bound of the current dimension
* and l_i the lower bound of the current dimension.
*/
for (i = dims; i > 0;) {
size_t dim = map[--i];
ir_node *lb, *ub, *elms, *n, *ind;
elms = NULL;
lb = get_array_lower_bound(arr_ty, dim);
ub = get_array_upper_bound(arr_ty, dim);
if (! is_Unknown(lb))
lb = new_rd_Conv(dbg, bl, copy_const_value(get_irn_dbg_info(sel), lb, bl), mode_Int);
else
lb = NULL;
if (! is_Unknown(ub))
ub = new_rd_Conv(dbg, bl, copy_const_value(get_irn_dbg_info(sel), ub, bl), mode_Int);
else
ub = NULL;
/*
* If the array has more than one dimension, lower and upper
* bounds have to be set in the non-last dimension.
*/
if (i > 0) {
assert(lb != NULL && "lower bound has to be set in multi-dim array");
assert(ub != NULL && "upper bound has to be set in multi-dim array");
/* Elements in one Dimension */
elms = new_rd_Sub(dbg, bl, ub, lb, mode_Int);
}
ind = new_rd_Conv(dbg, bl, get_Sel_index(sel, dim), mode_Int);
/*
* Normalize index, id lower bound is set, also assume
* lower bound == 0
*/
if (lb != NULL)
ind = new_rd_Sub(dbg, bl, ind, lb, mode_Int);
n = new_rd_Mul(dbg, bl, ind, last_size, mode_Int);
/*
* see comment above.
*/
if (i > 0)
last_size = new_rd_Mul(dbg, bl, last_size, elms, mode_Int);
newn = new_rd_Add(dbg, bl, newn, n, mode);
}
} else {
/* no array type */
ir_mode *idx_mode = get_irn_mode(index);
ir_tarval *tv = new_tarval_from_long(get_mode_size_bytes(basemode), idx_mode);
newn = new_rd_Add(dbg, bl, get_Sel_ptr(sel),
new_rd_Mul(dbg, bl, index,
new_r_Const(irg, tv),
idx_mode),
mode);
}
} else if (is_Method_type(get_entity_type(ent)) && is_Class_type(owner)) {
/* We need an additional load when accessing methods from a dispatch
* table.
* Matze TODO: Is this really still used? At least liboo does its own
* lowering of Method-Sels...
*/
ir_mode *ent_mode = get_type_mode(get_entity_type(ent));
int offset = get_entity_offset(ent);
ir_mode *mode_Int = get_reference_mode_signed_eq(mode);
ir_tarval *tv = new_tarval_from_long(offset, mode_Int);
ir_node *cnst = new_rd_Const(dbg, irg, tv);
ir_node *add = new_rd_Add(dbg, bl, get_Sel_ptr(sel), cnst, mode);
ir_node *mem = get_Sel_mem(sel);
newn = new_rd_Load(dbg, bl, mem, add, ent_mode, cons_none);
newn = new_r_Proj(newn, ent_mode, pn_Load_res);
} else {
int offset = get_entity_offset(ent);
/* replace Sel by add(obj, const(ent.offset)) */
newn = get_Sel_ptr(sel);
if (offset != 0) {
ir_mode *mode_UInt = get_reference_mode_unsigned_eq(mode);
ir_tarval *tv = new_tarval_from_long(offset, mode_UInt);
ir_node *cnst = new_r_Const(irg, tv);
newn = new_rd_Add(dbg, bl, newn, cnst, mode);
}
}
/* run the hooks */
hook_lower(sel);
exchange(sel, newn);
}
